NONSTOP VARIABLE SPEED GEAR DESCRIPTION Technical Field The present invention relates to a nonstop speed change friction apparatus used in automobiles or a variety of industrial transmission gears and more particularly, to a nonstop speed change friction apparatus capable of effectively transmitting a driving force of a driving part to a driven part and exhibiting an extensive speed change range.

Background Art Generally, a speed change apparatus functions to change the driving force (i. e., rotating speed and direction) of a driving part to be transmitted to a driven part in accordance with the load and working state of the driving part, such that a desired load and working state can be transmitted to the driven part.

Examples of the speed change apparatus are a gear speed change apparatus in which a plurality of gears are installed between a driving shaft and a driven shaft and the combination of the gears is thus varied to transmit a driving force; a fluid speed change apparatus in which impellers in a driving shaft side are combined with impellers in a driven shaft side to transmit a driving force by means of a fluid such as oil; a friction pulley apparatus in which a belt is wound on a driving shaft and a driven shaft to transmit a driving force by the formation of the friction therebetween; and a belt pulley apparatus in which two stepped pulleys as integrally formed to each other on which the belt pulleys having different diameters are arranged are installed on a driving shaft and a driven shaft in order to be changed in their directions, thereby transmitting a driving force by means of the

belt pulleys.

Among the above-discussed examples, the gear speed change apparatus, the fluid speed change apparatus and the belt pulley apparatus transmit the driving speed and the driving force in a multistage manner, but the friction pulley apparatus transmits the driving speed and the driving force in a nonstop manner.

Specifically, the friction pulley apparatus installs conical driving shaft and driven shaft to be crossed each other and mounts a belt on the driving shaft and the driven shaft, so that the speed change can be carried out in accordance with the variation of the position of the belt.

In the driving manner, the speed and power of the driving shaft are transmitted to the driven shaft via the belt, that is, the sliding friction force of the belt on the driving shaft and the driven shaft.

The conventional known friction pulley apparatuses, however, fail to effectively transmit the power of the driving shaft to the driven shaft by virtue of only the sliding friction force of the belt. As a result, the conventional friction pulley apparatuses suffer from problems that an accurate rotary speed ratio cannot be obtained and the loss of power is increased during a transmission process.

Therefore, there occur some disadvantages that the overload of the driving shaft may be caused due to the ineffective power transmission and the excessive consumption of the fuel in driving the driving shaft may be accompanied.

Disclosure of Invention It is, therefore, an object of the present invention to provide a nonstop speed change friction apparatus capable of reinforcing a sliding friction force of a belt, to thereby obtain

a rotary speed ratio in an accurate manner and transmitting the power of a driving shaft to a driven shaft in an effective manner, to thereby reduce the loss of power.

To attain this and other objects of the present invention, there is provided a nonstop speed change friction apparatus that variably changes power of a driving friction pulley in a nonstop manner and transmits the resulting power to a driven friction pulley, comprises: a belt transmission part having a plurality of coupling pieces connected to each other, each of the coupling pieces having a friction ring coming in contact with the outer peripheral surfaces of the driving friction pulley and the driven friction pulley and wound several times on the driving and driven friction pulleys to thereby transmit the power of the driving friction pulley to the driven friction pulley by the friction force produced from the friction ring; a guide part for guiding the plurality of coupling pieces to prevent them from being slid on the outer peripheral surfaces inclined of the driving and driven friction pulleys; a guide moving part for moving the guide part on the outer peripheral surfaces of the driving and driven friction pulleys to thereby move the plurality of coupling pieces on the outer peripheral surfaces of the driving and driven friction pulleys by means of the guide part, such that the power of the driving friction pulley is changed at its speed and transmitted to the driven friction pulley; and a control part for controlling the driving of the guide moving part to thereby limit the moving of the guide part on the outer peripheral surfaces of the driving and driven friction pulleys within a predetermined distance.

Brief Description of Drawings Fig. 1 illustrates the construction of a nonstop speed change friction apparatus according to a first embodiment of the present invention; Fig. 2 is a sectional view taken along the line 11-11'in Fig. 1;

Fig. 3 is a partly perspective view illustrating the belt transmission part as a main part in Fig. 1; Fig. 4 is a sectional view taken along the line IV-IV'in Fig. 3; Figs. 5 to 7 illustrate the operation of the guide moving part in Fig. 1; Fig. 8 illustrates the construction of a nonstop speed change friction apparatus according to a second embodiment of the present invention; Fig. 9 illustrates the guide moving part in Fig. 8; and Figs. 10 and 11 illustrate the operation of the guide moving part in Fig. 8.

Best Mode for Carrvinz Out the Invention Now, an explanation of the construction of a nonstop speed change friction apparatus according to a first embodiment of the present invention will be hereinafter discussed with reference to the accompanying drawings.

Figs. 1 to 4 illustrate the construction of the nonstop speed change friction apparatus according to the first embodiment of the present invention.

As shown, the nonstop speed change friction apparatus of the present invention is provided with a substantially conical driving friction pulley 11 connected to a driving shaft 10 to which power is transmitted from an engine E as a driving part and a substantially conical driven friction pulley 21 connected to a driven shaft 20 to which a driven part is connected, for driving a wheel W as the driven part with the power of the driving friction pulley 11.

There is also provided a belt transmission part for transmitting the power transmitted to the driving friction pulley 11 from the engine E to the driven friction pulley 21.

As illustrated in Fig. 3, the belt transmission part of a chain belt shape, which is composed of a plurality of coupling pieces 30 fixedly connected to each other by means of a fixing pin 33 and a friction ring 31 fixedly mounted to surround the outer periphery of each coupling piece 30, is wound several times on the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21, whereby the plurality of friction rings 31 come in contact with the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21.

In this way, the connected interval between the coupling pieces 30 should be substantially narrow, so that when the belt transmission part is wound on the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21, the bending of the connected portion between the coupling pieces can be minimized.

As shown in Fig. 4, the friction ring 31 is provided with a friction material 32 having a high friction factor such as asbestos used as a brake lining material, which serves to increase the sliding friction force of the friction ring 31 against the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21, such that the power of the driving friction pulley 11 can be transmitted to the driven friction pulley 21 in a stable manner.

And, referring to Fig. 2, there is provided a tension maintaining roller 33 which is adapted to maintain the tension of the coupling pieces 30 on a rotation moving path of the coupling pieces 30 wound several times on the driving friction pulley 11 and the driven friction pulley 21.

The nonstop speed change friction apparatus of the present invention is further provided with a guide part for carrying out the left and right sliding movements and guiding for the belt transmission part (composed of the coupling pieces 30, the friction ring

31 and the friction material 32) wound several times on the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21 and a guide moving part for moving the guide part, thereby enabling the nonstop speed change.

The guide part includes a' ['-shaped guide cap 40 having a top end 40-1 that is positioned on the top end of the outer peripheral surface of the driving friction pulley 11 and a bottom end 40-2 that is disposed on the bottom end of the outer peripheral surface of the driven friction pulley 21. And, a guide roller 42 is installed by means of a shaft pin 41 on the top end 40-1 and the bottom end 40-2 of the guide cap 40, respectively. The guide roller 42 is adapted to prevent the friction ring 31 from being slid during the rotation of the coupling pieces 30 and to forcedly push the coupling pieces 30 to thereby move them on the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21.

Referring to Figs. 1 and 5, the guide moving part uses a part of the power of the driven friction pulley 21, which fixedly installs a driving spur gear 51 on the driven shaft 20 of the driven friction pulley 21 and a first deceleration gear 52 engaged with the driving spur gear 51 and a second deceleration gear 53 engaged with the first deceleration gear 52, thereby decelerating the rotation of the driving spur gear 51 at a predetermined speed.

There is also provided a driven gear 54 that is selectively engaged with any of the first and second deceleration gears 52 and 53 and connected to a spiral driven shaft 55 moving the guide cap 40 left and right. The spiral driven shaft 55 is slantingly passed through the guide cap 40, as shown in Figs. 1 and 2.

The guide moving part will be in more detail discussed with reference to Fig. 5. As shown, the first and second deceleration gears 52 and 53 are engaged to each other and fixedly installed on the one end of a gear fixing plate 56 rotating left and right at a

predetermined interval on the basis of a fixing hinge 57, with a consequence that they are selectively engaged with the driven gear 54 in accordance with the rotation of the gear fixing plate 56.

In this case, on the one side of the gear fixing plate 56 there are provided a rack gear (which is not shown in the drawing), so that the first and second deceleration gears 52 and 53 are selectively engaged with the driven gear 54 and a driving motor 58 that moves the gear fixing plate 56 by a predetermined distance with a pinion gear shaft (which is not shown in the drawing) engaged with the rack gear.

The driving motor 58 is employed with a servomotor or a stepping motor.

And, the driving motor 58 receives the sensed signal from first and second proximity switches 60 and 61 installed on any one end of the both ends of each of the driving friction pulley 11 and the driven friction pulley 21 and is connected to a controller 70 that receives an operating signal of the driving motor 59 from the outside.

Under the above construction, an operation of the nonstop speed change friction apparatus according to the first embodiment of the present invention will be in detail discussed.

Referring to Fig. 1, if a predetermined power is firstly transmitted from the driving part such as the engine E to the driving shaft 10, the driving friction pulley 11 rotates to enable the plurality of coupling pieces 30 to rotate, whereby the power is transmitted to the driven friction pulley 21 to enable the driven shaft 30 to rotate, thereby driving the driven part such as the wheel W.

At this time, the coupling pieces 30 are wound several times and include the friction rings 31 each forming the friction material thereon, such that they can generate a substantially high friction force against the outer peripheral surfaces of the driving friction

pulley 11 and the driven friction pulley 21. As a consequence, due to the generation of the friction force, the sliding of the coupling pieces 30 can be desirably prevented and on the other hand, the sliding friction force can be increased, thereby achieving the power transmission in a stable manner.

In this state, the guide moving part is maintained in the same state as in Fig. 5.

That is, the first and second deceleration gears 52 and 53 are not engaged with any of the driving gear 51 and the driven gear 54.

Hence, the driven gear 54 is not rotated, thus not to spirally rotate the driven shaft 55, such that the guide gap 40 is not moved.

If the power transmitted to the driven shaft 20 is to be decreased and if the rotation speed of the driven shaft 20 is to be increased, the guide cap 40 should be moved in a direction of an arrow A.

To this end, as shown in Fig. 6, the controller 70 drives the driving motor 58, and the driving motor 58 rotates the gear fixing plate 56 on the basis of the fixing hinge 57, while carrying out the rack-pinion gear movement, whereby the first deceleration gear 52 is engaged with the driven gear 54.

Thereafter, the driven gear 54 allows the driven shaft 55 to be spirally advanced in a forward direction, while rotating in the same direction as in the driving gear 51, thereby pulling the guide cap 40 toward the direction of the arrow A and moving it. At this time, the guide roller 42 pushes and moves the coupling pieces 30 in the direction of the arrow A.

Next, if the first proximity switch 60 senses the fact that the guide cap 40 moves to the direction of the arrow A, it sends the sensing signal to the controller 70, and as a result, the controller 70 rotates the driving motor 58 in a reverse direction thereto, with a consequence that the first deceleration gear 52 is separated from the driven gear 54, thus

not to spirally advance the driven shaft 55.

On the other hand, if the power transmitted to the driven shaft 20 is to be increased and if the rotation speed of the driven shaft 20 is to be decreased, the guide cap 40 should be moved in a direction of an arrow B.

To this end, as shown in Fig. 7, the controller 70 drives the driving motor 58, while carrying out the rack-pinion gear movement, whereby the second deceleration gear 53 is engaged with the driven gear 54.

Thereafter, the driven gear 54 allows the driven shaft 55 to be spirally advanced in a reverse direction thereto, while rotating in the different direction from that in the driving gear 51, thereby pulling the guide cap 40 toward the direction of the arrow B and moving it.

At this time, the guide roller 42 of the guide cap 40 pushes and moves the coupling pieces 30 in the direction of the arrow B.

Next, if the second proximity switch 61 senses the fact that the guide cap 40 moves to the direction of the arrow B, it sends the sensing signal to the controller 70, and as a result, the controller 70 rotates the driving motor 58 in a reverse direction thereto, with a consequence that the state as shown in Fig. 5 is formed (i. e., the first and second deceleration gears 52 and 53 are not engaged with the driven shaft 55). As a result, the controller 70 stops the movement of the guide cap 40, which causes the coupling pieces 30 not to be further moved toward the direction of the arrow B.

Of course, the nonstop speed change friction apparatus of the present invention can embody the guide part and the guide moving part in different shapes and ways. Hence, an explanation of the construction of a nonstop speed change friction apparatus according to a second embodiment of the present invention will be hereinafter discussed with reference to Figs. 8 and 9.

In the second embodiment, a guide part has guide caps 80-1 and 80-2 covering predetermined portions of the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21, in place of the' ['-shaped guide cap in the first embodiment and guide rollers 42-1 and 42-2 for closely contacting the coupling pieces 30 in the interior of the guide caps 80-1 and 80-2 to thereby push and move them.

The guide moving part is formed so that a first driving spur gear 91 is fixedly installed on the driven shaft 20, a first deceleration gear 92 engaged with the first driving spur gear 91 and a second deceleration gear 93 engaged with the first deceleration gear 92 are installed on the one side of the gear fixing plate 56, and the gear fixing plate 56 is rack- pinion gear-coupled with the driving motor 58 and moves left and right in accordance with the driving of the diving motor 58.

The operation principle of the gear fixing plate 56 of the second embodiment of the present invention is the same as the first embodiment of the present invention, an explanation of which will be avoided for the brevity of the description.

Additionally, there is provided a mid gear 99 that is engaged with any of the first and second deceleration gears 92 and 93 as the gear fixing plate 56 moves. Further, third and fourth deceleration gears 94 and 95 are installed to be symmetrical relative to the mid gear 99.

The first and second deceleration gears 94 and 95 is respectively connected to a guide cap driving shaft 98 that is passed through the guide caps 80-1 and 80-2, respectively, such that they are engaged correspondingly with first and second driven gears 96 and 97 spirally moving in a forward or backward direction in accordance with the rotation of the third and fourth deceleration gears 94 and 95, thereby moving the guide caps 80-1 and 80-2.

Under the above construction, an operation of the nonstop speed change friction

apparatus according to the second embodiment of the present invention will be in detail discussed.

Referring to Figs. 8 and 9, a predetermined power is firstly transmitted from the driving part such as the engine E to the driving shaft 10, the driving friction pulley 11 rotates to enable the plurality of coupling pieces 30 to rotate, whereby the power is transmitted to the driven friction pulley 21 to enable the driven shaft 30 to rotate, thereby driving the driven part such as the wheel W.

At this time, the coupling pieces 30 are wound several times and include the friction rings 31 each forming the friction material thereon, such that they can generate a substantially high friction force against the outer peripheral surfaces of the driving friction pulley 11 and the driven friction pulley 21. As a consequence, due to the generation of the friction force, the sliding of the coupling pieces 30 can be desirably prevented and on the other hand, the sliding friction force can be increased, thereby achieving the power transmission in a stable manner.

And, the first and second deceleration gears 92 and 93 are not engaged with the mid gear 99, such that the third and fourth deceleration gears 94 and 95 do not rotate, thereby stopping the operation of the first and second driven gears 96 and 97.

Therefore, the guide cap driving shaft 98 is not spirally moved, so that the guide caps 80-1 and 80-2 are not moved.

If the power transmitted to the driven shaft 20 is to be decreased and if the rotation speed of the driven shaft 20 is to be increased, the guide caps 80-1 and 80-2 should be moved in a direction of an arrow C.

To this end, the driving motor 58 operates to enable the gear fixing plate 56 to carry out the rack-pinion gear movement, such that the first deceleration gear 92 is engaged with

the mid gear 99, which enables the third and fourth deceleration gears 94 and 95 to be rotated in a forward direction. As a result, the first and second driven gears 96 and 97 are rotated in the same direction as in the third and fourth deceleration gears 94 and 95, i. e., in the forward direction (see Fig. 10).

Thereafter, the guide cap driving shaft 98 pulls and moves the guide caps 80-1 and 80-2 in the direction of the arrow C, while spirally moving in the forward direction, and the guide rollers 42-1 and 42-2 of the guide caps 80-1 and 80-2 forcedly move the wound coupling pieces 30.

The movement of the guide caps 80-1 and 80-2 to the direction of the arrow C stops in accordance with the existence and non-existence of the sensing signal of the first proximity switch 60, which adapts the same principle as the forward direction moving stop of the guide cap in the first embodiment of the present invention.

On the other hand, if the power transmitted to the driven shaft 20 is to be increased and if the rotation speed of the driven shaft 20 is to be decreased, the guide caps 80-1 and 80-2 should be moved in a direction of an arrow D.

To this end, the driving motor 58 operates to enable the gear fixing plate 56 to carry out the rack-pinion gear movement, such that the second deceleration gear 93 is engaged with the mid gear 99.

Thereby, the mid gear 99 enables the third and fourth deceleration gears 94 and 95 to be rotated in a reverse direction thereto. As a result, the first and second driven gears 96 and 97 are rotated in the same direction as in the third and fourth deceleration gears 94 and 95, i. e., in the reverse direction thereto (see Fig. 11).

Thereafter, the guide cap driving shaft 98 pulls and moves the guide caps 80-1 and 80-2 in the direction of the arrow D, while spirally moving in the reverse direction, and the

guide rollers 42-1 and 42-2 of the guide caps 80-1 and 80-2 forcedly move the wound coupling pieces 30.

The movement of the guide caps 80-1 and 80-2 to the direction of the arrow D stops in accordance with the existence and non-existence of the sensing signal of the second proximity switch 61, which adapts the same principle as the reverse direction moving stop of the guide cap in the first embodiment of the present invention.

Industrial Applicability As clearly appreciated from the above, a nonstop speed change friction apparatus according to the present invention comprises a belt transmission part where a plurality of coupling pieces are coupled to each other, each coupling piece having a friction ring on which a friction material having a high friction factor such as asbestos is attached, the plurality of coupling pieces coupled being wound several times and rotated on the outer peripheral surfaces of the driving friction pulley and the driven friction pulley, whereby a sliding friction force is increased between the coupling pieces and the outer peripheral surfaces of the driving friction pulley and the driven friction pulley, such that the power that is transmitted from the driving part such as an engine can be effectively transmitted to the driven part such as a wheel.

In addition, the nonstop speed change friction apparatus according to the present invention further comprises a guide cap that is adapted to close and move the coupling pieces wound and rotated on the outer peripheral surfaces of the driving friction pulley and the driven friction pulley and a guide moving part which automatically operates the guide cap by using a part of the power of the driven friction pulley, whereby the speed change efficiency can be improved and the speed change range can be expanded.