CHAIN BELT AND BELT TYPE CONTINUOUSLY VARIABLE TRANSMISSION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese Patent Application

No. 2008-010518, filed January 21, 2008 and Japanese Patent Application No. 2008-271758, filed October 22, 2008, the contents of both are hereby incorporated by reference in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

[0002] The present disclosure relates to a chain belt and a belt-type continuously variable transmission. More particularly, the present disclosure relates to a chain belt which has a plurality of link plates provided with pin engaging portions at both ends, and rocker pins which connect the link plates in an articulated manner, and which is connected by the rocker pins in a continuous manner. Additionally, the present disclosure relates to a belt-type continuously variable transmission using a chain belt.

Description of the Related Art

[0003] In recent years, belt-type continuously variable transmissions in which rotation power is transmitted continuously have become commercially practical. In the belt- type continuously variable transmissions, V-pulleys having circumferential grooves (V-grooves) of V-shaped cross section are disposed on a pair of parallel rotation shafts. A metal belt is wound between the pulleys, and the V-groove widths of both the pulleys are associated with each other on a drive side and a follower side so that gears may be changed continuously.

[0004] One metal belt used in the belt-type continuously variable transmissions of this kind is a conventionally known chain belt in which both ends of rocker pins, which connect a large number of link plates with each other, are brought into contact with V-groove surfaces of the pulley to transmit power (see, Japanese Patent Application National Publication (Laid-Open) No.2005-531734 and Japanese Patent Application Publication (JP-B) No.7-1055).

[0005] In Japanese Patent Application National Publication (Laid-Open) No.2005-

531734, link plates having two kinds of lengths (pitch distances) are arranged in the

chain belt at random, thereby separating frequency peaks in power transmission so that generated noise is reduced.

[0006] In Japanese Patent Application Publication (JP-B) No.7-1055, an intermediate block which comes into contact with a V-groove surface of the pulley is mounted on the link plate, a contact pitch is shortened by three point contact of the rocker pins and the intermediate block, input per one contact with the V-groove surface is reduced, and generated noise is reduced.

[0007] In Japanese Patent Application National Publication (Laid-Open) No.2005-

531734, however, vibration energy caused by a chain may be reduced at a predetermined frequency by randomizing, but a distance between the rocker pins in the chain, i.e., a pitch distance is large. Therefore, the vibration energy itself is large, and there is a problem that noise is increased in a resonance frequency area of a part around the chain.

[0008] If the pitch distance is narrowed to reduce the vibration energy, there is a problem that the number of parts is increased and cost is increased.

[0009] In JP-B No.7-1055, because a pivot shape with respect to the V-groove surface of the intermediate block is largely different from the pivot shape by the rocker pin, a deformation amount caused by contact reaction force against the V-groove surface is different from that of the rocker pin. Thus, a region where three points, i.e., the rocker pins and the intermediate block do not come into contact with each other (or the V-groove surface) at the same time exists, and there is a problem that the reduction of noise is limited to a particular winding radius of the pulley.

SUMMARY OF THE CLAIMED SUBJECT MATTER

[0010] In one aspect, embodiments of the present disclosure relate to a torque transmitting apparatus including at least two pulleys and a chain belt assembly to transfer torque between the at least two pulleys, wherein the chain belt assembly includes a first link plate comprising a first end and a second end, a second link plate comprising a third end aligned with the first end in a first direction, a third link plate having a fourth end aligned with the second end in the first direction, a first rocker pin disposed through the first end and the third end, a second rocker pin disposed through

the second end and the fourth end, and a transfer pin disposed through the first link plate in a location between the first rocker pin and the second rocker pin.

[0011] In another aspect, embodiments of the present disclosure relate to a chain belt of a continuously variable transmission including a first link plate having a first end and a second end, a second link plate having a third end aligned with the first end, a third link plate having a fourth end aligned with the second end, a first rocker pin disposed through the first end and the third end, a second rocker pin disposed through the second end and the fourth end, and a transfer pin disposed through the first link plate in a location between the first and second rocker pins.

[0012] In another aspect, embodiments of the present disclosure relate to a method to transmit torque between two V-pulleys including disposing a chain belt assembly between the two V-pulleys, connecting a first link plate of the chain belt assembly to a second link plate of the chain belt assembly with a first rocker pin, connecting the first link plate of the chain belt assembly to a third link plate of the chain belt assembly with a second rocker pin, connecting the first link plate of the chain belt assembly to a fourth link plate of the chain belt assembly with a transfer pin, and transmitting torque between the chain belt assembly and a V-groove of at least one of the two V-pulleys through friction contact at an end of at least one of the first rocker pin, the second rocker pin, and the transfer pin, wherein the transfer pin is disposed through the first link plate between the first rocker pin and the second rocker pin.

[0013] In another aspect, embodiments of the present disclosure relate to a chain belt to transmit torque between at least two pulleys including a first link plate having a first end and a second end, a second link plate having a third end aligned with the first end, a third link plate having a fourth end aligned with the second end, a first pin means for securing the first end to the third end, a second pin means for securing the second end to the fourth end, and a transfer pin means for transferring torque between the chain belt and the at least two pulleys, wherein the transfer pin means is located between the first and the second pin means and extends through the first link plate in a direction substantially perpendicular to a direction of the chain belt extending between the at least two pulleys.

BRIEF DESCRIPTION OF DRAWINGS

[0014] Features of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings.

[0015] Fig. 1 is a schematic view of a link plate, a rocker pin, and a transfer pin used with a chain belt for a continuously variable transmission in accordance with an exemplary embodiment of the present disclosure.

[0016] Fig. 2 is a partial front view showing a structure of the chain belt of Fig. 1.

[0017] Fig. 3 is a front view showing the chain belt of the embodiment shown in Fig.

1 wound around a pulley.

[0018] Fig. 4 is a sectional schematic view depicting a gear change state of the chain belt as it is wound around the pulley.

[0019] Fig. 5 is an explanatory schematic diagram explaining a contact state between the pulley and the chain belt shown in Fig. 4.

[0020] Fig. 6 is a schematic view showing a comparative example of the chain belt.

[0021] Fig. 7 is a characteristic view showing a variation in transmission driving force in the chain belt of the embodiment together with the comparative example.

[0022] Fig. 8 is a schematic view showing a second exemplary embodiment of a chain belt in accordance with the present disclosure.

[0023] Fig. 9 is a structure diagram showing details of a chain belt for a continuously variable transmission of the second exemplary embodiment in accordance with the present disclosure.

[0024] Fig. 10 is an explanatory diagram for explaining a relation between a transfer pin and a link plate.

[0025] Fig. 11 is an explanatory diagram showing a state of large speed change ratio in a state where it is wound around a driving pulley.

[0026] Fig. 12 is an explanatory diagram showing a state of small speed change ratio in a state where it is wound around the driving pulley.

[0027] Fig. 13 is an explanatory diagram for explaining an application force generated in the link plate.

[0028] Fig. 14 is an explanatory diagram showing the second exemplary embodiment of the chain belt.

DETAILED DESCRIPTION

[0029] A chain belt and a belt-type continuously variable transmissions of the present disclosure will be explained based on embodiments.

[0030] Figs. 1 to 7 depict a first exemplary embodiment of the chain belt and the belt- type continuously variable transmissions to which the present disclosure applied.

[0031] Fig. 1 is a schematic view of a link plate, a rocker pin and a transfer pin used for the chain belt of the embodiment. Fig. 2 is a partial front view showing a structure of the chain belt of the embodiment. Fig. 3 is a front view showing the chain belt of the embodiment in a state where the chain belt is wound around pulleys. Fig. 4 is a sectional view for explaining a gear changing state in a state where the chain belt is wound around the pulleys. Fig. 5 is a diagram for explaining a contact state between the pulleys and the chain belt shown in Fig. 4. Fig. 6 is a schematic view showing a chain belt of a comparative example. Fig. 7 is a characteristic view showing a variation in transmission driving force in the chain belt of the embodiment together with the comparative.

[0032] The chain belt 1 for the continuously variable transmission of the embodiment is wound and used between a driving pulley and a follower pulley (i.e., the pulley driven by driving pulley) in which a fixed sheave and a movable sheave having opposed tapered surfaces constitute a V-groove.

[0033] More specifically, a plurality of link plates 2 (first link plates) may be arranged in a stack direction. Ends of the link plates 2 are superposed on ends of a plurality of link plates 2 (second and third link plates) arranged in the stack direction which are adjacent in a longitudinal direction of the chain belt 1. A pair of rocker pins 3 (i.e., first and second "pairs" of rocker pins) which may move in an articulated manner penetrate and connect corresponding ends of the adjacent link plates, thereby constituting a continuous ring belt. In the following description, each pair of rocker

pins 3 may collectively be called "rocker pins", such that each rocker pin may include an inner pin 3 A and an outer pin 3B.

[0034] Each link plate 2 arranged in the stack direction may hold and include a transfer pin 4 (i.e., a third pin) disposed in parallel to the rocker pins 3 at a central portion of the link plate 2 in the longitudinal direction. The transfer pin 4 may be a rod-like part for transmitting power to the pulleys which is added independently from the rocker pins 3. As shown in Fig. 2, the transfer pin 4 may extend between outer peripheral ends of the adjacent link plates 2 connected by the rocker pins 3 to the link plate 2 which holds the transfer pin 4 and the rocker pins 3.

[0035] The rocker pins 3 and the transfer pin 4 may be formed by cutting an extracted

(e.g., extruded and/or drawn) material which may be created with a forming die of a particular cross-sectional shape. Furthermore, the as-extracted material may be subjected to finishing following extraction. Inclined surfaces are formed on both ends of each of the rocker pins 3 and the transfer pin 4 projecting from the link plate 2, which come into contact with V-groove surface 13 formed into a tapered surface opposed to the fixed sheave 11 and the movable sheave 12 of the pulleys 10 (i.e., 1OA and 10B). The inclined surfaces may be subjected to crowning processing for rounding (i.e., crowning) and projecting its central portion so that it may come into surface-contact with the fixed sheave 11 and movable sheave 12 of the pulley 10. Therefore, even if the pulley 10 is deformed, the contact state is not changed and the pulley 10 may be reduced in thickness. In addition, a winding diameter of the pulley 10 may be reduced.

[0036] When the chain belt 1 is wound around the driving pulleys 1OA and 1OB, both ends of the rocker pin 3 and the transfer pin 4 and the V-groove surface 13 of pulleys 1OA and 1OB come into contact with each other so that the chain belt 1 may transmit a driving force therebetween. As shown with solid lines in Fig. 4, a state in which the movable sheave 12 is brought closer to the fixed sheave 11, a pulley 10 diameter is increased to be a "large diameter." As shown with broken lines, a state in which the movable sheave 12 is (axially) separated from the fixed sheave 11, the pulley diameter is reduced to a "small diameter." If the driving pulley 1OA and the follower pulley 1OB are associated with each other and the pulley diameter of each pulley 1OA

and 1OB is changed, the transmission ratio may be varied continuously in a stepless manner.

[0037] The link plate 2 is formed from a flat plate through a die cutting process by means of fine blanking from which high precision is obtained relatively easily. As shown in Fig. 2, the entire outer shape of link plate 2 has a rectangular and annular shape. The link plate defines an inner peripheral surface in the longitudinal direction, and the inner peripheral surface further defines pin engaging portions 5 at each end of the link plate. A back surface side of the outer pins 3B of each of the rocker pins 3 with respect to the inner pins 3 A engage the respective pin engaging portions 5. As described later, each pin engaging portion 5 has a shape which allows the inner pin 3A to roll and move with respect to the outer pin 3B.

[0038] The pin engaging portions 5 on the both ends may be in communication with each other through a through hole formed by a space in the longitudinal direction whose width is reduced. Thus, the inner peripheral surface may be a continual surface that defines each of the pin engaging portions 5 as well as the transfer pin portion (accommodating portion 6), with the transfer pin portion and the pin engaging portions all being open to each other (in communication).

[0039] In a central region of the link plate 2 between the pin engaging portions 5 on both sides, upper and lower edge portions forming the through hole is recessed in inner and outer diameter directions, and an accommodating portion 6 which allows the transfer pin 4 to penetrate and accommodates the transfer pin 4 is formed. Thus, the inner peripheral surface may further define transfer pin retention features within the transfer pin portion (accommodating portion 6) to retain the transfer pin 4 within the transfer pin portion (to keep the transfer pin 4 from entering the pin engaging portions 5).

[0040] In the following description, an outer peripheral side of the chain belt 1 formed into a ring shape is referred to as the "outer diameter side", and an inner peripheral side is referred to as the "inner diameter side".

[0041] As shown in Fig. 1, in the central region of the accommodating portion 6 formed in the link plate 2 between the pin engaging portions 5, the upper and lower edge portions may project inward, and edge portions of the projected regions may be

partially recessed. Thus, the transfer pin retaining features may protrude inward from the inner peripheral surface of the link plate 2 at the accommodating portion 6, and the transfer pin retaining features may include recesses in which the transfer pin may sit to remain within the accommodating portion 6.

[0042] As shown in Fig. 1, the transfer pin 4 may be disposed at an intermediate position at distances c and d from the left and right rocker pins 3, which are spaced from each other at a distance b. As would be understood by those having ordinary skill, the distances c and d may be about equal to each other (i.e., c = d) or may be different from each other (i.e., c ≠ d). Alternatively, the pin engaging portions 5 into which the rocker pins 3 of the link plate 2 are inserted and the accommodating portion 6 in which the transfer pin 4 is accommodated may also be formed as a series of separate through-holes as shown in Fig. 3.

[0043] As described above, rocker pins 3 may comprise a pair of pins 3 A and 3B and may include opposing surfaces for rolling contact with each other. Ends of the adjacent link plates 2 may be superposed on each other in a staggered configuration (e.g., the left side of a first link plate may line up with the right side of a second link plate, and the right side of the first link plate may line up with the left side of a third link plate) and the rocker pins 3 may be inserted into the pin engaging portions 5. The pair of pins 3 A and 3B of each rocker pin 3 may be configured such that the outer pin 3 B of each link plate 2 is integrally engaged with the pin engaging portion 5, and the inner pin 3A of each link plate 2 is spaced apart from the pin engaging portion 5 of the link plate 2.

[0044] Thus, as shown in Fig. 2, the outer pin 3B of the pair of pins 3 A and 3B of the rocker pin 3 inserted into the pin engaging portion 5 of the link plate 2 which is located at a central portion may be integrally engaged with an inner surface on the' side of separated ends of the left and right pin engaging portions 5 of the link plate 2 located at the central position. The inner pin 3 A of the pair of pins 3 A and 3 B may be integrally engaged with the inner surface on the side of the end of the pin engaging portion 5 of the link plate 2 which is connected to the end in the articulated manner.

[0045] Referring to Fig. 2, there are three link plates 2 shown: a left plate (lightly dotted), a right plate (heavily dotted), and a center plate (solid line) superposed on top

of the left and right plates. The rocker pins 3 may be inserted through the pin engaging portions 5 of the center plate in a configuration where outer pin 3 B contacts the pin engaging portion of the center plate, and the inner pin may pass through to the plates below to engage the pin engaging portions of the respective left and right plates. Further, inner pin 3A may engage the inner surface by contacting the outside of the transfer pin engaging features of the first exemplary embodiment (Fig. 2), as well as contacting the pin engaging portion 5 on the side opposite the outer pin 3B in the second exemplary embodiment (Fig. 9, discussed below)

[0046] Thus, when the chain belt 1 is wound around the pulley 10 from the linear state and when the chain belt 1 is separated from the pulley 10 and is brought into the straight state and the chain belt 1 is bent, the outer pin 3B of the pair of pins 3 A and 3 B turns integrally with the link plate 2, and the inner pin 3 A turns integrally with the link plate 2 which is adjacent to the former link plate 2. As a result, the link plates 2 which are connected to each other in the articulated manner in adjacent to each other are connected by the rolling contact of the pair of pins 3 A and 3B of the rocker pins 3 which connects the link plates 2, and the link plates 2 rotate relatively.

[0047] In the chain belt 1 for the continuously variable transmission of the first exemplary embodiment, the transfer pin 4 may be added between the rocker pins 3. By adding the transfer pin 4, the contact pitch distance to the pulley 10 may be reduced by about half without shortening the length of the link plate 2. Fig. 5 shows a contact state between the rocker pin 3 and the transfer pin 4 to the V-groove surface 13 when the chain belt 1 is wound around the pulley 10 in a state where the pulley diameter is increased and in a state where the pulley diameter is reduced in accordance with a speed change ratio (analogous to a gear ratio of a standard "geared" transmission).

[0048] When the chain belt 1 is wound in a state where the pulley diameter is increased in accordance with the speed change ratio, because the radii of curvature of the fixed sheave 11 and the movable sheave 12 constituting the pulley 10 are large, the offset amount X to the outside of the transfer pin 4 with respect to the left and right rocker pins 3 (i.e., the distance between the centers of contact) may become relatively small as shown on the outer side in the radial direction. When the chain belt 1 is wound in a state where the pulley diameter is reduced in accordance with the

speed change ratio, because the radii of curvature of the fixed sheave 11 and the movable sheave 12 constituting the pulley 10 are small, the offset amount X to the outside of the transfer pin 4 with respect to the left and right rocker pins 3 may become relatively large as shown on the inner side in the radial direction.

[0049] As the chain belt 1 is wound around the pulley 10, end surfaces of the pair of outer pins 3B of the leading rocker pin 3 may come into contact with the V-groove surface 13 of the pulley 10 and then, the end surfaces of the pair of inner pins 3 A may come into contact with the V-groove surface 13 of the pulley 10. The rocker pin 3 is pushed against the V-groove surface 13 from the outer diameter side in the radial direction of the pulley 10 against a compression force which acts to bring the fixed sheave 11 and the movable sheave 12 close to each other. As a result, a friction force in the circumferential direction is generated on the V-groove surface 13 of the pulley 10 and the end surface of the rocker pin 3, power is transmitted from the V-groove surface 13 of the pulley 10 to the rocker pin 3, and is transmitted to the link plate 2. At the same time, the pair of outer pin 3B and inner pin 3A rolls by the winding curvature.

[0050] Next, the end surface of the transfer pin 4 comes into contact with the V- groove surface 13 of the pulley 10. With this, the transfer pin 4 also comes into contact with the V-groove surface 13 of the pulley 10 on the same radius of curvature as that of the rocker pin 3, and transmits power. Thereafter, the trailing rocker pin 3 (inner pin 3A and the outer pin 3B) then comes into contact with the V-groove surface 13 of the pulley 10 on the same radius of curvature, and rolls and transmits power.

[0051] Fig. 7 shows variation of power transmission in the state where the chain belt

1 is wound around the pulley 10 according to the first exemplary embodiment in comparison with power transmission in a chain belt 1 in a comparative example. As shown in Fig. 6, two kinds of link plates 2 which have different length (i.e., a ≠ b) are disposed in one chain belt 1 at random was selected as the chain belt 1 of the comparative example.

[0052] In the chain belt 1 of the comparative example, a state where power transmission curve by the trailing rocker pin 3 in a stage where the power transmission curve by the leading rocker pin 3 sufficiently fell from the peak rises is

repeated, and variation width of the power transmission force is relatively largely generated. This is generated because after the leading rocker pin 3 comes into contact with the V-groove surface 13 of the pulley 10 and the power transmission is deteriorated, the motion in which the trailing rocker pin 3 comes into contact and the power transmission is started is repeated. Thus, the graph shows the process of the leading rocker pin 3 contacting the surface, and the power transfer increasing, reaching a peak, and decreasing. The trailing rocker pin 3 makes contact and follows a similar pattern. Thus, the delay between contact timings of each rocker pin may cause the amount of power transfer to fluctuate greatly. Therefore, the power transmission error (rotation inconsistency) may be large, the vibration energy may be great, and noise is large. Because the contact load between the rocker pin 3 and the V-groove surface 13 becomes large, there is a problem that the wearing of the rocker pin 3 is large and the endurance is deteriorated.

[0053] In the chain belt 1 of the first exemplary embodiment, while the power transmission curve by the leading rocker pin 3 falls from the peak, the power transmission curve by the transfer pin 4 rises, and while the power transmission curve by the transfer pin 4 falls from the peak, the power transmission curve by the reciprocating rocker pin 3 rises, and these operations are alternately repeated. Thus, the variation width of the power transmission force is suppressed to relatively small value. As a result, the vibration energy may be reduced by about half, power transmission error (rotation inconsistency) may be small, and noise may be reduced. Because the noise is proportional to the cube of pitch (i.e., ∞ p ³ ) and because the pitch may be reduced by about half, the noise may be reduced by about 1/8. Further, the contact load between the rocker pin 3, the transfer pin 4 and the V-groove surface 13 may be reduced, the wear resistance of the rocker pin 3 and the transfer pin 4 may be enhanced, and endurance may be enhanced. Further, because the pitch distance of the pin may be reduced by about half without shortening the length of the link plate 2, noise may be reduced without increasing the number of links and thus the relative increase in cost may be minimized.

[0054] As shown in Fig. 1, the transfer pin 4 is disposed at a distance c from the left rocker pin 3 and at a distance d from the right rocker pin 3. Because the distances c and d are not equal (i.e., c ≠ d), the pitches may not be equal. This may easily be

changed by changing the position of the accommodating portion 6 {i.e, the hole) of the transfer pin 4. As a result, the harmonic vibration frequency may further be changed, and the effect for reducing noise may further be enhanced.

[0055] Referring now to Fig. 8, an alternative embodiment of the chain belt 1 of the present disclosure is shown. According to the alternative embodiment, a center of contact between the transfer pin 4 and the V-groove surface 13 of the pulley 10 may be offset (e.g., displaced toward the outer diameter side) from a straight line connecting the centers of the contact points between the left and right rocker pins 3 and the V-groove surface 13 from a winding curvature of the pulley. With this structure, the transfer pin 4 may come into contact with the V-groove surface 13 of the pulley 10 like the rocker pins 3 on the both sides, and the contact load between the transfer pin 4 and the end surface of the rocker pin 3 may further be dispersed. Thus, the wear on the end surface of each pin may be reduced and durability is enhanced.

[0056] Although continuously variable transmissions are typically constructed by winding the chain belt 1 around the V-pulley 10 having a fixed sheave 11 and a movable sheave 12, in this embodiment, the chain belt 1 may be wound between a V- pulley having fixed sheaves on the both sides (not shown).

[0057] In this (alternative) embodiment, the following effects may be exhibited.

[0058] (A) The chain belt 1 for the continuously variable transmission connected in the continuous manner may include a plurality of link plates 2 each provided with the pin engaging portions 5 at both ends, and the rocker pins 3 which are engaged with the engaging portions 5 of the link plates 2 and which are connected to the adjacent link plates 2 in the articulated manner. The accommodating portion 6 of the transfer pin 4 may be provided between the pin engaging portions 5 of the link plates 2. The transfer pin 4 may be disposed through the accommodating portion 6 substantially parallel to the rocker pins 3. Both end surfaces of the rocker pin 3 may be brought into friction contact with the V-pulley 10, constituting first and second contact points between the chain belt and the pulley, and both end surfaces of the transfer pin 4 may be brought into friction contact with the V-pulley 10, constituting a third contact point between the chain belt and the pulley.

[0059] With the above structure, the contact pitch distance to the V-pulley 10, though the addition of transfer pins 4, may be reduced by about half without shortening the length of the link plate 2. Thus, noise may also be reduced without increasing the number of links, thus cost may not be increased.

[0060] (B) As shown in Fig. I ₅ the transfer pin 4 may be deviated to either way in the longitudinal direction of the chain belt 1 from the intermediate position of the left and right rocker pins 3, so that the vibration frequency by contact with the V-groove surface 13 of the pulley 10 may be dispersed, and the effect for reducing the noise may be enhanced.

[0061] (C) The transfer pin 4 may be disposed between the left and right rocker pins

3, the length of the link plate 2 may be shortened, so that the contact pitch distance to the V-groove surface 13 of the pulley 10 constituted by the rocker pin 3 and the transfer pin 4 may be shortened, and the noise may be reduced.

[0062] (D) As shown in Fig. 8, the transfer pin 4 may be offset toward the outer side of the chain belt 1, and the transfer pin 4 may be offset outward by the pulley winding curvature when the chain is wound around the V-groove surface 13 of the pulley 10, so that the transfer pin 4 may come into contact with the rocker pin 3 on the same pitch circumference, the contact load of each pin end surface may be dispersed such that wear of each pin end surface may be dispersed, and lifetime enhanced.

[0063] (Second exemplary embodiment)

[0064] Figs. 9 to 14 show a second exemplary embodiment of the chain belt and the belt-type continuously variable transmissions to which the present disclosure is applied. Fig. 9 is a structure diagram showing details of the chain belt. Fig. 10 is an explanatory diagram for explaining a relation between a transfer pin and a link plate. Figs. 11 and 12 are explanatory diagrams showing a state of the large speed change ratio and small speed change ratio in the winding state of the driving pulley 1OA. Fig. 13 is an explanatory diagram for explaining an application force generated in the link plate. Fig. 14 is an explanatory diagram showing the second exemplary embodiment of the chain belt.

[0065] In this second exemplary embodiment, a structure in which the transfer pin 4 is brought into contact with and engagement with an arc projection (i.e., the contoured

surface of the link plate 2) provided on an end of the link plate 2 may be added to the first exemplary embodiment. Similar devices and parts as those of the first exemplary embodiment are designated with the same symbols, and explanation thereof will be omitted or simplified.

[0066] In Fig. 9, the transfer pin 4 is shown disposed between the left and right rocker pins 3 of the chain belt 1 of this embodiment. The transfer pin 4 is disposed at a distance from the accommodating portion 6 (i.e., the hole) of the link plate 2 which accommodates the transfer pin 4 in the inner and outer diameter directions of the chain belt 1, and the transfer pin 4 may move in the inner and outer diameter directions. Thus, there may be a gap between the top and bottom of the transfer pin 4 and the top and bottom of the accommodating portion 6 so that the transfer pin is given some room to move vertically within the accommodating portion as the adjacent link pins 2 contact and push the transfer pin 4 as the chain belt 1 bends and unbends.

[0067] Engaging grooves 7 may be formed in both surfaces of the transfer pin 4 in the longitudinal direction of the chain belt 1. As shown, engaging grooves 7 are recesses formed having substantially arc-shaped cross sections which may correspond to and engage arc projections on the longitudinal ends of the link plates 2 in the axial direction of the transfer pin 4.

[0068] An end of the link plate 2 disposed so as to be opposed to the engaging groove

7 of the transfer pin 4 may include an arcuate projection 8 which may be configured to engage engaging groove 7 of the transfer pin 4.

[0069] Fig. 10 is an enlarged view of an engaging state between the engaging groove

7 and the arcuate or arc- shaped projection 8. The engaging groove 7 may be formed as a substantially arcuate shape around a rolling contact point of the rocker pin 3 which make the link plate 2 which holds the transfer pin 4 and the link plates 2 disposed adjacent to the link plate 2. A distance between the rocker pin 3 and the rolling contact point may be a radius of the arcuate shape. Thus, the arc-shaped projection 8, and the corresponding engaging groove 1 , may be shaped to correspond to the arc formed by the rolling contact between the inner pins 3A and outer pins 3B of the rolling pin 3 which may, in turn, dictate the degree of bending of the adjacent link plates 2.

[0070] The arc-shaped projection 8 engaged within the engaging groove 7 formed on the end of the link plate 2 may include an arc shapes C2 which intersect a radial direction line Cl, an arc shape B2 which intersects with the radial direction line Bl and an arc shape A2 which intersects with the radial direction line Al.

[0071] The arc shape B2 may be formed into a partial arc of arc shape B around the rolling contact point of the rocker pin 3. A distance between the rolling contact point and the rocker pin 3 having the same radius is a radius of the partial arc.

[0072] The arc shape C2 may be formed into a partial arc of the arc shape C, and this partial arc is formed around a portion of the rocker pin 3 which is offset from the rolling contact point toward the outer diameter side (upper side in the drawing) of the chain.

[0073] The arc shape A2 may be formed into a partial arc of the arc shape A, and this partial arc is formed around a portion of the rocker pin 3 which is offset from the rolling contact point toward the inner diameter side (lower side in the drawing) of the chain.

[0074] Each of the arc shapes A2 to C2 may be formed such that they are connected to the arc shape B2 intersecting with the radial direction line Bl while gradually reducing the offset amount from the arc shape C2 intersecting the radial direction line Cl to the outer diameter side of the arc center. Each of the arc shapes A2 to C2 may be formed such that it is connected to the arc shape A2 intersecting with the radial direction line Al while gradually increasing the offset amount from the arc shape B2 intersecting the radial direction line Bl to the inner diameter side of the arc center. That is, the shape of the arc projection 8 may include a contour formed by an envelope connecting these arc shapes A2 to C2. Other structure is the same as that of the first exemplary embodiment.

[0075] The radial direction line Al connecting the arc A shown with the broken lines in Fig. 10 and the center of the arc A shows an arrangement of the arc projection 8 in which the radial direction lines Al become one straight line when the chain belt 1 becomes a straight line, as shown in Fig. 9. The radial direction line Bl connecting the arc B shown with chain lines in Fig. 10 and the center of the arc B shows an arrangement of the arc projection 8 in which the arc regions shown with the radial

direction lines Bl are engaged with the lower region of the engaging groove 7 of the transfer pin 4 when the chain belt 1 is bent to the side of the follower pulley 10 at a predetermined curvature in the OD (over drive) state, as shown in Fig. 12. The radial direction line Cl connecting the arc C shown with phantom lines in Fig. 10 and the center of the arc C shows an arrangement of the arc projection 8 in which the arc regions shown with the radial direction lines Cl are engaged with the lower region of the engaging groove 7 of the transfer pin 4 when the chain belt 1 is bent to the side of the driving pulley 10 at a large curvature in the LOW (low speed drive) state and the chain belt 1 is bent to the side of the follower pulley 10 at a predetermined curvature in the OD (over drive) state, as shown in Fig. 11. The offsets of the arcs A to C and the center positions thereof in the radial directions Al to Cl (inner and outer diameter directions of the chain belt 1) are formed to change the holding position of the transfer pin 4 in the inner and outer diameter directions of the chain belt 1 in accordance with the bending state of the chain belt 1.

[0076] Therefore, in the chain belt 1 of the second exemplary embodiment, the position of the transfer pin 4 in the inner and outer diameter directions of the chain belt 1 may be varied in accordance with a variation (the offset) in relative position in the inner and outer diameter directions (inner and outer diameter directions of the chain belt 1) of the arc projection 8 in accordance with a relative bending angle between the link plate 2 which accommodates the transfer pin 4 and a link plate 2 which is adjacent to the former link plate 2.

[0077] More specifically, in the state where the adjacent link plates 2 become a straight line, as shown in Fig. 9, the adjacent link plates 2 are arranged in the straight line, the center of the arc projection 8 may be located at the innermost diameter side (i.e., the lower side in the drawing). With this, the position of the transfer pin 4 having the engaging groove 7 which is engaged with the arc projection 8 in the inner and outer diameter directions is also located at the innermost side (lower side in the drawing). In this state, because the transfer pin 4 is not in contact with the pulley 10, an external force from the pulley 10 is not applied, and the transfer pin 4 is positioned only by engagement between the arc projection 8 and the engaging groove 7.

[0078] In a state where the adjacent link plates 2 are relatively largely bent, both the adjacent link plates 2 are largely bent and arranged as shown in Fig. 11. If the

transfer pin 4 comes into contact with the pulley 10, an external force for moving the transfer pin 4 in the outer diameter direction of the chain belt 1 may be applied to the transfer pin 4. Therefore, the arc projection 8 is located (offset) at the outermost inner and outer diameter directions (upper side in the drawing), arc regions shown with the radial direction lines Cl are engaged with the lower region of the engaging groove 7 of the transfer pin 4, the inner and outer direction position of the transfer pin 4 is located at the outermost side (upper side in the drawing), and the transfer pin 4 is held against the external force from the pulley 10. In this case, a rotation component of turning movement of a pair of link plates 2 which is disposed on left and right sides in adjacent to each other on both sides of the chain belt 1 in the longitudinal direction around a rolling point of the rocker pin 3 of the arc projection 8 is absorbed by variation of a contact position caused by slip between the arc projection 8 and the engaging groove 7 of the transfer pin 4, and only the offset moving component to the outer side of the arc projection 8 in the inner and outer diameter directions is transmitted to the transfer pin 4, and the transfer pin 4 is moved outward in the inner and outer directions. Similarly, in a state where relative bending of the adjacent link plates 2 becomes relatively small, they are arranged such that the bending of the adjacent link plates 2 becomes small, as shown in Fig.12. In this case also, if the transfer pin 4 comes into contact with the pulley 10, an external force for moving the transfer pin 4 in the outer diameter direction of the chain belt is applied. Thus, the arc projection 8 is located (offset) inward in the inner and outer diameter directions (lower side in the drawing) than the LOW driving state, the arc regions shown with the radial direction lines Bl are engaged with the lower region of the engaging groove 7 of the transfer pin 4, the position of the transfer pin 4 in the inner and outer diameter directions is located inward from the LOW driving state (lower side in the drawing), and the transfer pin 4 is held against the external force from the pulley 10. In this case also, the rotation component of turning movement of a pair of link plates 2 which is disposed on left and right sides in adjacent to each other on both sides of the chain belt 1 in the longitudinal direction around a rolling point of the rocker pin 3 of the arc projection 8 is absorbed by variation of a contact position caused by slip between the arc projection 8 and the engaging groove 7 of the transfer pin 4, and only the offset moving component to the outer side of the arc projection 8 in the radial direction is

transmitted to the transfer pin 4, and the transfer pin 4 is moved outward in the inner and outer directions.

[0080] In the chain belt 1 described in the first exemplary embodiment, the transfer pin 4 may be fixed and held in a state where the transfer pin 4 restrains the movement of the link plate 2 in inner and outer directions by the accommodating portion 6 (hole). Therefore, it is preferable that the transfer pin 4 is offset and disposed outward in the inner and outer direction from the left and right rocker pins 3 so that the transfer pin 4 comes into contact on the same circle as the contact pitch circle to the pulley 10 of the rocker pin 3 as close as possible. However, if the transfer pin 4 is offset and position thereof is set in correspondence with a region where the winding radius of the pitch circle of a specific radius of curvature, the transfer pin 4 is added and three-point contact is established at the time of LOW driving where the winding radius on the side of the driving pulley 1OA is small and at the time of OD driving where the winding radius on the side of the follower pulley 1OB is small, but in other speed change ratio, the contact between the transfer pin 4 and the pulley 10 is not achieved, only the two-point contact is established, and there exists a region where the contact pitch is large and noise is large.

[0081] However, in the chain belt 1 of the embodiment, when the radius of curvature is small, it is positioned (offset) radially outward largely with respect to the left and right rocker pins 3, it comes in contact with the contact points on the same pitch circle as that of the rocker pin 3, and three-point contact with respect to the pulley 10 is secured. As the radius of curvature of the winding around the pulley 10 is increased, the offset amount outward in the inner and outer directions with respect to the left and right rocker pins 3 of the transfer pin 4 is reduced, the transfer pin 4 comes into contact with the contact points on the same pitch circle as that of the rocker pin 3, and the three-point contact with the pulley 10 is maintained.

[0082] Therefore, in the chain belt 1 of the embodiment, the position (offset amount) of the transfer pin 4 in the inner and outer direction disposed between the rocker pins 3 may be controlled in accordance with the winding curvature around the pulley 10 due to a variation of speed change ratio, and the three-point contact may be maintained and secured not only at a specific speed change ratio but also in all speed change ratios. Thus, the transfer pin 4 of the chain belt 1 of the embodiment is outset

to the outermost side at the time of LOW driving, and the offset amount to slightly outside is reduced at the time of OD driving in correspondence with the small winding radius. With this, the three-point contact on the chain pitch circle may be established in any speed change ratio corresponding to the variation of winding radius, and it is possible to maintain the meshing pitch at a small value and to reduce noise.

[0083] In the embodiment, the arc projection 8 formed on the end of the link plate 2 and engaged with the engaging groove 7 includes a contour formed by an envelope in an arc region which intersects with the radial direction lines Al to Cl, but the shape of the arc projection 8 is not limited to this example, and the shape may be another cam shape which establishes the same motion.

[0084] Fig. 13 is an explanatory diagram showing an application force generated when the chain belt 1 of the embodiment is wound around the pulley 10. A reaction force (link tension FO) from the pair of pins (inner pin 3 A and outer pin 3B) of the left and right rocker pins 3 (which come into contact with opposed sheaves of the pulley 10 which is not shown) is applied to each link plate 2. The link tension FO is applied so as to pull the link plate 2 in the longitudinal direction of the link plate 2, and the link tension FO is received by inner and outer ribs 2A in the inner and outer direction of the link plate 2.

[0085] A contact reaction force Fl outward in the inner and outer direction is applied to the transfer pin 4 by the contact of the opposed tapered sheaves 11 and 12 of the pulley 10 (not shown). The contact reaction force Fl is applied to a contact portion between the engaging grooves 7 formed in both side surfaces of the transfer pin 4 and the arc projections 8 of the pair of link plates 2 disposed on the left and right sides in adjacent on both sides of the chain belt 1 in the longitudinal direction. This contact reaction force may be offset by a composite reaction force F3 by the contact reaction force F2 inward in the inner and outer direction, and the inner and outer direction position of the transfer pin 4 is held. At the same time, an application force F4 outward in the inner and outer direction applied to the arc projection 8 of the link plate 2 from the contact portion is applied opposed to the tension FO of the link plate 2, and the application force F4 acts so as to cancel a portion of the tension FO. Therefore, the strength of the link plate 2 is enhanced and the capacity of the chain belt 1 is increased.

[0086] In the chain belt 1 of another example of this embodiment shown in Fig. 14, the transfer pin 4 may be divided into two pieces, and they may be held by the accommodating portions 6 of the link plates 2. The accommodating portions 6 may be independent from each other, and they may be formed as through-holes connected to the pin engaging portions 5 of the rocker pins 3 on both sides. The transfer pins 4 may be engaged with the arc projections 8 of the adjacent link plates 2 on one side of the engaging groove 7. Thus, the transfer pin 4, the link plate 2 may include two independent accommodating portions 6, and two transfer pins 4 inserted into respective accommodating portions 6 to establish a four point contact with the pulleys 10.

[0087] In the chain belt 1 of this example also, like the example shown in Figs. 9 to

12, a position of the transfer pin 4 in the inner and outer direction (offset amount) may be controlled in accordance with the bending angle of the link plates 2 which may be varied by the winding curvature when the chain belt 1 is wound around the pulley 10, and the four-point contact may be maintained and secured not only at a specific speed change ratio but also in all speed change ratios.

[0088] Thus, it is slightly outset to the outermost side at the time of LOW driving to meet the small winding radius, and the offset amount is slightly reduced at the time of OD driving to meet the large winding radius, and the four-point contact on the pitch circle may be established in any speed change ratio. Thus, the meshing pitch may be maintained at a smaller value by the left and right rocker pins 3 and the two transfer pins 4, and noise may further be reduced. Even if the contact pitch is the same as that of the first example, because the length of the link plate 2 is increased, it is possible to reduce the number of link plates 2 and the number of pins.

[0089] Like Fig. 13, the application force Fl outward in the radial direction applied to the transfer pins 4 by the contact with the sheave of the pulley 10 may be applied to the contact portion between the engaging groove 7 and the arc projection 8, this is offset by the composite reaction force F3 inward in the inner and outer direction by the contact reaction force F2, and the position of the transfer pins 4 in the inner and outer direction is held. At the same time, the application force F4 outward in the inner and outer direction applied to the arc projection 8 of the link plate 2 from the contact portion may be applied opposed to the tension FO of the link plate 2, and acts

so as to cancel a portion of the tension FO. Because the canceling force may not be applied between the two transfer pins 4, it may be necessary to increase the strength of the inner and outer ribs 2A of the link plate 2, but the strength of the rib 2A may easily be enhanced by increasing the rib width. Therefore, in this example also, it may be possible to further enhance the strength of the link plate 2 and to increase the capacity of the chain belt 1 and the link plate 2.

[0090] In this embodiment, as the engaging structure between the transfer pin 4 and the pair of link plates 2 disposed on the left and right sides in adjacent to each other on both sides of the chain belt 1 in the longitudinal direction, the structure in which the arc contact surfaces of the engaging groove 7 and the projection 8 provided on the side of the transfer pin 4 are engaged with each other has been explained. Although not illustrated, one of them may be formed into an arc surface and the other may come into contact with the arc surface. One of the engaging groove 7 and the arc projection 8 is formed with a cam surface, the contact point between the engaging groove 7 and the projection 8 is changed in accordance with variation of the relative bending curvature of the pair of link plates 2 disposed on the left and right sides adjacent to each other on both sides of the link plate 2 in the longitudinal direction, and the position of the transfer pin 4 in the inner and outer direction (radial direction with respect to the pulley) may be positively controlled.

[0091] In this embodiment, the following effect may be obtained in addition to the effects (A) to (C) of the first exemplary embodiment.

[0092] (E) The transfer pin 4 may be restrained from moving to the outer diameter side of the chain belt I ₅ and at least a portion of the biasing force toward the outer diameter side generated in the transfer pin 4 when the chain belt is wound around the pulley 10 may be converted into a compression force of the link plate 2 through the engaging portion. The link tension- may be reduced or offset by the compression force, stress generated in the link plate 2 may be reduced and the lifetime of the link plate 2 may be enhanced. The torque capacity of the chain belt 1 may also be enhanced.

[0093] (F) The engagement between the transfer pin 4 and the end of the link plate 2 may change a position of the transfer pin 4 in the inner and outer diameter directions of the chain belt 1 in accordance with the relative bending curvature of the left and

right link plates 2 which is moved by the left and right rocker pins 3 in the articulated manner. The position in the radial direction where the transfer pin 4 comes into contact with the pulley 10 may follow in accordance with the winding curvature around the pulley 10 which is changed by the speed change ratio between the driving pulley 1OA and the follower pulley 1OB, the three-point contact at which the contact pitch may be reduced by half may be established in addition to the left and right rocker pins 3 not only at a specific speed change ratio but also in all speed change ratios, and it is possible to reliably reduce the chain noise.

[0094] (G) The engagement between the transfer pin 4 and the end of the link plate 2 may change a portion of the turning motion of the arc projection around the rocker pin 3 in the ends of the left and right link plates 2 which are moved in the articulated manner by the left and right rocker pins 3 to a position of the transfer pin 4 in the inner and outer diameter directions of the chain belt 1. With this, it is possible to control the position of the transfer pin 4 in the inner and outer diameter directions of the chain belt 1 without increasing the number of parts, it is possible to enhance the reliability of the driving system of the continuously variable transmission, and this is advantageous to suppress the cost of manufacturing.

[0095] (H) As shown in Fig. 14, two transfer pins 4 may be disposed between the left and right rocker pins 3, and may be engaged with the ends of the corresponding left and right link plates 2, thereby restraining the chain belt 1 from moving toward the outer diameter side, the left and right rocker pins 3 are added and the four-point contact may be established, and even if the contact pitch is the same, because the size of the link plate 2 in the longitudinal direction is increased, the number of link plates 2 and the number of pins 3 and 4 may be reduced.

[0096] Advantageously, embodiments disclosed herein relate to a chain belt suitable to reduce a contact pitch distance with a pulley in belt-type continuously variable transmissions. Embodiments disclosed herein disclose a chain belt including a first link plate in which a plurality of flat plates are laminated (or stacked) in a plate- thickness direction, second and third link plates in which a plurality of flat plates are laminated in the plate-thickness direction on both sides in a longitudinal direction of the first link plate, and ends of the first link plates are superposed on each other, first and second pins which connect the superposed ends of the second and third link plates

and the first link plate with each other such as to penetrate the ends in the plate- thickness direction, and a third pin which penetrates the first link plate in the plate- thickness direction and disposed in parallel to the first pin and the second pin between the second link plate and the third link plate.

[0097] Therefore, in select embodiments of the present disclosure, the chain belt may include a third pin disposed in parallel to the first pin and the second pin connecting the link plates while penetrating the first link plate in the plate-thickness direction between the second link plate and the third link plate disposed on left and right sides of the first link plate in the longitudinal direction. The plurality of link plates may be connected in the longitudinal direction in a continuous manner. Thus, it may be possible to reduce the contact pitch distances of the pins by about half, which may facilitate power transmission without shortening the length of the link plate. Also, the number of link parts may not be increased, therefore keeping costs reduced and suppressing noise.

[0098] While embodiments disclosed herein are described in the context of a continuously variable transmission for an automobile, those having ordinary skill will appreciate that the apparatus and methods disclosed herein may be applied to any apparatus or method to transmit torque between pulleys. For example, no embodiment of the present disclosure should be limited to pulleys having adjustable- width V-grooves as disclosed in that the chain belt apparatus and methods disclosed herein may be applied to constant-width or "non-variable" torque transmission pulleys. Furthermore, embodiments disclosed herein may also be applicable to other torque transmission applications, automotive or other, where torque and/or power is transmitted between at least a pair of pulleys. For example, and engine accessory (e.g., an air conditioner compressor, an alternator, a water pump, etc.) may be driven using chain belts and pulleys as disclosed herein.

[0099] While the present disclosure has been presented with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments may be devised which do not depart from the scope of the present disclosure. Accordingly, the scope of the invention as claimed should be limited only by the attached claims.