BLOCK ARRANGEMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Patent Application No. 62/448,427 filed on January 20, 2017. The disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates generally to transmission shift assemblies and more particularly to a transmission shift assembly having a self-contained interlock block arrangement.

BACKGROUND

[0003] Transmission shift assemblies allow a vehicle operator to selectively change gear ratios during vehicle operation. A manual shift assembly can be provided that allows a vehicle operator to determine when a shifting event is to be initiated. Typically many gear ratios are provided to provide a user a varied range of speeds to select during use. A manual transmission typically includes a shift knob that is movable between a plurality of shift positions such as first, second, third, fourth, fifth, sixth, etc. In addition, a reverse position is provided that allows a user to select a reverse gear. It is desirable to inhibit inadvertent selection of reverse gear.

[0004] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0005] A transmission shift assembly for a transmission constructed in accordance to one example of the present disclosure includes an interlock block assembly and a rail assembly. The rail assembly includes a first/second rail that supports a first/second shift yoke and a third/fourth rail that supports a third/fourth shift yoke. The interlock block assembly and the shift rail assembly are assembled as a unit prior to assembling into the transmission.

[0006] According to additional features, the rail assembly further includes a reverse rail that supports a reverse shift yoke. The interlock block assembly can include an interlock block housing that receives a detent ball assembly and an interlock ball assembly. The interlock block housing can define a first bore and a second bore. The first bore can receive the first/second rail. The second bore can receive the third/fourth rail.

[0007] In other features, the interlock block housing can define a transverse bore that extends generally transverse relative to the first and second bores. The transverse bore can receive the interlock ball assembly. The first/second shift rail defines a first interlock groove and a second interlock groove. The first interlock groove selectively receives an interlock ball of the first pair of interlock balls when the third/fourth shift rail is in an in-gear position. The second interlock groove selectively receives an interlock ball of the second pair of interlock balls when the reverse shift rail is in an in-gear position.

[0008] According to other features, the first/second shift rail defines a transverse passage that receives an interlock pin. The interlock pin translates within the transverse passage depending upon the gear selected. The third/fourth shift rail defines an interlock groove that selectively receives an interlock ball of the first pair of interlock balls when the third/fourth shift rail is not in gear. The reverse shift rail defines an interlock groove that selectively receives an interlock ball of the second pair of interlock balls when the reverse shift rail is not in gear. The first/second shift rail defines a neutral detent ball groove that selectively receives a first detent ball of the detent ball assembly when not in gear. The third/fourth shift rail defines a neutral detent ball groove that selectively receives a second detent ball of the detent ball assembly when not in gear.

[0009] In additional features, the reverse shift rail defines a neutral ball groove that selectively receives a third detent ball of the detent ball assembly when not in gear. The transmission shift assembly further includes a first, second and third biasing member. The first biasing member is housed in a first longitudinal extension of the interlock block assembly. The first biasing member biases the first detent ball toward the first/second shift rail. The second biasing member is housed in a second longitudinal extension of the interlock block assembly. The second biasing member biases the second detent ball toward the third/fourth shift rail. The third biasing member is housed in a third longitudinal extension of the interlock block assembly. The third biasing member biases the third detent ball toward the reverse rail. The first, second and third longitudinal extensions each include a groove that receives respective first, second and third snap rings. The first, second and third snap rings capture the first, second and third biasing members within the longitudinal extensions.

[0010] A method of assembling a transmission shift assembly into a transmission according to one example of the present disclosure includes assembling the transmission shift assembly and subsequently assembling the transmission shift assembly relative to the transmission front housing. Assembling the transmission shift assembly includes assembling an interlock block assembly. A rail assembly having a first/second shift rail and a third/fourth shift rail is assembled. A first/second shift yoke is assembled to the first/second shift rail. A third/fourth shift yoke is assembled to the third/fourth shift rail.

[0011] In other features, biasing member associated with longitudinal extensions on the interlock block assembly are compressed. The biasing members are retained in respective bores defined in the longitudinal extensions. The biasing members can be compressed concurrently. Snap rings can be placed within grooves defined in the longitudinal extensions thereby capturing the biasing members within the respective bores.

[0012] A transmission constructed in accordance to one example of the present disclosure includes a gear train and a shift assembly. The gear train has a plurality of traction components. The transmission shift assembly is configured to shift between the gears of the gear train in the transmission. The transmission shift assembly includes an interlock block assembly and a rail assembly. The rail assembly includes a first/second rail that supports a first/second shift yoke and a third/fourth rail that supports a third/fourth shift yoke. The interlock block assembly and the shift rail assembly are assembled as a unit prior to assembling into the transmission. The rail assembly further includes a reverse rail that supports a reverse shift yoke. The interlock block assembly can include an interlock block housing that receives a detent ball assembly and an interlock ball assembly. The interlock block housing can define a first bore and a second bore. The first bore can receive the first/second rail. The second bore can receive the third/fourth rail.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0014] FIG. 1 is perspective view of a transmission shift assembly having a self- contained interlock block arrangement constructed in accordance to one example of the present disclosure;

[0015] FIG. 1 A is a schematic illustration of the transmission shift assembly shown in an exemplary transmission.

[0016] FIG. 2 is a close up perspective view of an interlock block assembly of the transmission shift assembly of FIG. 1 ;

[0017] FIG. 3 is a perspective view of the transmission shift assembly of FIG. 2 shown with an interlock block housing of the interlock block assembly removed;

[0018] FIG. 4 is a cross-sectional view of the interlock block assembly of the transmission shift assembly taken along lines 4-4 of FIG. 2 and shown with the reverse rail in an in-gear position;

[0019] FIG. 5 is a cross-sectional view of the interlock block assembly of the transmission shift assembly taken along lines 4-4 of FIG. 2 and shown with the first/second rail in an in-gear position; and

[0020] FIG. 6 is a cross-sectional view of the interlock block assembly of the transmission shift assembly taken along lines 4-4 of FIG. 2 and shown with the third/fourth rail in an in-gear position.

DETAILED DESCRIPTION

[0021] With initial reference to FIG. 1 , an exemplary transmission shift assembly constructed in accordance to one example of the present disclosure is shown and generally identified with reference numeral 10. The transmission shift assembly 10 is used in a transmission 12 (FIG. 1A) to shift between a collection of gears or gear train 16 for providing various gear ratios. In general, the transmission 12 includes an outer case that defines an internal cavity that contains components of the transmission 12. The case can be made from one or more castings, forgings, or other parts. As is known, the transmission 12 receives input torque from an engine and delivers output torque to driveline components. The case encloses the gear train 16. The gear train 16 includes a plurality of traction components that are adjustable to vary the ratios of both the speed and the torque of the output relative to the input. For example, the gear train may comprise meshed gears and/or planetary gear sets. The shift assembly 10 according to the present disclosure includes an interlock block assembly 16 and a rail assembly 20.

[0022] The rail assembly 20 includes a first/second shift rail 24, a third/fourth shift rail 26, and a reverse shift rail 32. The first/second shift rail 24 supports a first/second shift yoke 34. The third/fourth shift rail 26 supports a third/fourth shift yoke 36. The reverse shift rail 32 supports a reverse shift yoke 42. It is appreciated that the configuration of the shift assembly 10 shown is merely exemplary and that additional rails may be included such as a fifth/sixth rail. Similarly, the rail assembly 20 may be arranged to have fewer than three shift rails.

[0023] With additional reference now to FIGS. 2-4 additional features of the transmission shift assembly 10 will be further described. The interlock block assembly 16 generally includes an interlock block housing 50 that receives a detent ball assembly 52 and an interlock ball assembly 54. The interlock block housing 50 defines a first bore 60, a second bore 62 and a third bore 64. The first bore 60 partially receives the first/second rail 24. The second bore 62 partially receives the third/fourth rail 26 and the third bore 64 partially receives the reverse rail 32. First, second and third longitudinal extensions 70, 72 and 74 extend from the interlock block housing 50. In the example shown, the first, second and third longitudinal extensions 70, 72 and 74 are integrally formed with the interlock block housing 50.

[0024] The first longitudinal extension 70 defines an extension bore 70A that receives a first detent ball 80 of the detent ball assembly 52. A first biasing member 82 is housed in the extension bore 70A of the first longitudinal extension 70 and biases the first detent ball 80 toward the first/second shift rail 24. The second longitudinal extension 72 defines an extension bore 72A that receives a second detent ball 86 of the detent ball assembly 52. A second biasing member 88 is housed in the extension bore 72A of the second longitudinal extension 72 and biases the second detent ball 86 toward the third/fourth shift rail 26. The third longitudinal extension 74 defines an extension bore 74A that receives a third detent ball 90 of the detent ball assembly 52. A third biasing member 92 is housed in the extension bore 74A of the third longitudinal extension 74 and biases the third detent ball 90 toward the reverse rail 32.

[0025] Grooves 70B, 72B and 74B are further defined in the longitudinal extensions 70, 72 and 74 at the respective bores 70A, 72A and 74A. In some examples, snap rings 94, 96 and 98 can be disposed into the respective grooves 70B, 72B and 74B for retaining the biasing members 82, 88 and 92 within the bores 70A, 72A and 74A. It will be appreciated that additional or alternative configurations may be used to retain the respective biasing members 82, 88 and 92 within the bores 70A, 72A and 74A. In one arrangement, a round plug can additionally be pushed into each of the bores 70A, 72A and 74A and the snap rings 94, 96 and 98 may be positioned above the plugs.

[0026] Other components such as, but not limited to, threaded caps, non-threaded caps, plates or any component suitable to retain the respective biasing members 82, 88 and 92 within the bores 70A, 72A and 74A may be used. In one assembly step, smooth plugs can be concurrently deployed into the respective bores 70A, 72A and 74A such as by a fixture. Snap rings 94, 96 and 98 could then be inserted behind it. Those skilled in the art will appreciate that the transmission shift assembly 10 is self-contained and can be handled during assembly relative to the transmission.

[0027] The interlock block housing 50 defines a transverse bore 100 that extends generally transverse relative to the first, second and third bores 60, 62 and 64. The interlock ball assembly 54 includes a first pair of interlock balls 1 10 and a second pair of interlock balls 1 12. The first pair of interlock balls 1 10 is received in the transverse bore 100 and is positioned between the first/second shift rail 24 and the third/fourth shift rail 26. The second pair of interlock balls 1 12 is received in the transverse bore 100 and is positioned between the first/second shift rail 24 and the reverse shift rail 32.

[0028] The interlock block housing 50 further defines threaded bores 120 and pin bores 122. The threaded bores 120 receive mounting fasteners 126. The pin bores 122 receive mounting pins 128. The mounting fasteners 126 and mounting pins 128 facilitate mounting of the interlock block assembly 16, and the transmission shift assembly 10 as a whole to a front housing of the transmission (not specifically shown).

[0029] With particular reference now to FIGS. 3 and 4, the rail assembly 20 will be further described. The first/second shift rail 24 defines a neutral detent ball groove 130 that selectively receives the first detent ball 80. The third/fourth shift rail 26 defines a neutral detent ball groove 132 that selectively receives the second detent ball 86. The reverse shift rail 32 defines a neutral detent ball groove 134 that selectively receives the third detent ball 90.

[0030] The first/second shift rail 24 defines a first interlock groove 150 and a second interlock groove 152. The first interlock groove 150 selectively receives an interlock ball of the first pair of interlock balls 1 10 when the third/fourth shift rail 26 is in an in-gear position (see FIG. 6). The second interlock groove 152 selectively receives an interlock ball of the second pair of interlock balls 1 12 when the reverse shift rail 32 is in an in-gear position (see FIG. 4).

[0031] A transverse passage 154 is defined through the first/second shift rail 24 that receives an interlock pin 156. The interlock pin 156 translates within the transverse passage 154 depending upon the gear selected. Specifically, the interlock pin 156 translates leftward as viewed in FIG. 6 when the third/fourth shift rail 26 is in an in-gear position. The interlock pin 156 translates rightward as viewed in FIG. 4 when the reverse shift rail 32 is in an in-gear position.

[0032] The third/fourth shift rail 26 defines an interlock groove 160 that selectively receives an interlock ball of the first pair of interlock balls 1 10 when the third/fourth shift rail 26 is not in gear. The reverse shift rail 32 defines an interlock groove 166 that selectively receives an interlock ball of the second pair of interlock balls 1 12 when the reverse shift rail 32 is not in gear.

[0033] As can be appreciated, during shifting, the respective detent balls 80, 86 and 90 of the detent ball assembly 52 are caused to ramp in and out of the respective neutral detent ball grooves 130, 132 and 134. Specifically, when a shift rail is in an in-gear position, the corresponding shift rail translates along its axis such that the respective detent ball ramps out of the neutral detent ball groove. For example, as shown in FIG. 4, the reverse shift rail 32 is in an in-gear position and the detent ball 90 is urged against the biasing member 92 and out of the neutral detent ball groove 134. Similarly, as shown in FIG. 5, the first/second shift rail 24 is in an in-gear position and the detent ball 80 is urged against the biasing member 82 and out of the neutral detent ball groove 130. Likewise, as shown in FIG. 6, the third/fourth shift rail 26 is in an in-gear position and the detent ball 86 is urged against the biasing member 88 and out of the neutral detent ball groove 132.

[0034] In addition to the balls of the detent ball assembly 52 moving during a shifting event, the first and second pairs of interlock balls 1 10, 1 12 of the interlock ball assembly 54 also move. In this regard, when the reverse shift rail 32 moves from an in-gear position (FIG. 4) to an out-of-gear position (FIGS. 5 and 6), the pair of interlock balls 1 12 move from a position engaged with the interlock groove 152 on the first/second shift rail 24 to a position engaged with the interlock groove 166 on the reverse shift rail 32. When the third/fourth shift rail 26 moves from an in-gear position (FIG. 6) to an out-of-gear position (FIGS. 4 and 5), the pair of interlock balls 1 10 move from a position engaged with the interlock groove 150 on the first/second shift rail 24 to a position engaged with the interlock groove 160 on the third/fourth shift rail 26. When the first/second shift rail 26 moves from an in-gear position (FIG. 5) to an out-of-gear position (FIGS. 4 and 6), the first and second pair of interlock balls move from a position engaged with both of the interlock grooves 166 and 160 to a position engaged with one of the interlock grooves 150 (FIG. 6) and 152 (FIG. 4).

[0035] According to an advantage of the instant transmission shift assembly, the interlock block assembly 16 and the rail assembly 20 can be assembled as a unit prior to assembling into the transmission. Explained further, the components of the interlock block assembly 16 including the detent ball assembly 52 and the interlock ball assembly 54 can all be pre-assembled. Similarly, the rail assembly 20 can be coupled relative to the interlock block housing 50 prior to mounting the transmission shift assembly 16 into the transmission front housing. The interlock block assembly 16 together with the rail assembly 20 as a whole can subsequently be mounted to the transmission using the mounting fasteners 126 and mounting pins 128. Assembly efficiencies can be gained. [0036] The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.