DESC:TECHNICAL FIELD
[001] The embodiments herein generally relate to power transmission unit and more particularly, to a shift fork assembly in power transmission unit of vehicles, industrial machines and the like, which comprises a plurality of rolling elements adapted to restrict wear and tear of shift fork and synchronizer sleeve thereby increasing the life of the shift fork and the synchronizer sleeve.

BACKGROUND
[002] Generally, a power transmission unit (gear box assembly) of a vehicle comprises shift forks, which facilitates selection of corresponding gears thereby obtaining various gear ratios which are required for different driving conditions of the vehicle. The power transmission unit (gear box assembly) used in industrial machines and the like, also comprises shift forks for selection of corresponding gears thereby obtaining various gear ratios which are required for machining operation of the work piece or component. The shift fork is always in contact with a synchronizer sleeve of a synchronizer unit in power transmission unit (gearbox assembly). Further, the synchronizer units and the gears in power transmission unit (gearbox assembly) are rotating during gearshift irrespective of the current running gear. The contact between the shift fork tip and synchronizer sleeve of the synchronizer unit is of a sliding type. The constant sliding movement between the shift fork tip and the rotating synchronizer sleeve results in high friction and heat generation. Hence, the side of the shift fork tip and the synchronizer sleeve gets worn out gradually due to friction or heat generation thereby decreasing the life of the shift forks and the synchronizer sleeve.
[003] The rate of wear and tear in the shift fork is high when the vehicle is going down the gradient with an engine of the vehicle in non-operative condition (switch-off condition). As a result of the aforementioned driving condition of the vehicle, the forced lubrication in the power transmission unit is stopped which leads to loss of lubrication film between the shift fork tip and the rotating synchronizer sleeve. The vehicle engine is turned off while going down the gradient to save the fuel cost by the user. But this increases the wear and tear of all shift forks or the synchronizer sleeve, which is in mechanical contact, as the lubrication film between contact surfaces dry up. Further, the shift fork tips are positioned in such a way that it cannot be submerged in transmission oil.
[004] Conventional solutions to restrict wear and tear of shift fork of the power transmission unit include hardening the tip of the shift fork which is in sliding contact with rotating synchronizer sleeve, inserts of hardened metal to be provided between the shift fork tip and the synchronizer sleeve, usage of inserts made of alloys which have higher wear resistance and providing lubrication at the sliding contact between the shift fork tip and synchronizer sleeve. However, the aforementioned solutions incurs high cost due to the usage of superior metal/alloys and also lubricant oil is not provided in required amount at the sliding contact between the shift fork tip and synchronizer sleeve when the vehicle is going down the gradient with the engine in non-operative condition (switch-off condition).
[005] Therefore, there exists a need for a shift fork assembly for a power transmission unit of at least one of a vehicle, a machine and the like, which obviates the aforementioned drawbacks.

OBJECTS

[006] The principal object of an embodiment of this invention is to provide a shift fork assembly for a power transmission unit of at least one of a vehicle, a machine and the like, which comprises a plurality of rolling elements adapted to restrict wear and tear of shift fork and synchronizer sleeve thereby increasing the life of the shift fork and the synchronizer sleeve.
[007] Another object of an embodiment of this invention is to provide a shift fork assembly for a power transmission unit of at least one of a vehicle, a machine and the like, which has less friction and less heat generation between a shift fork and a synchronizer sleeve.
[008] Yet another object of an embodiment of this invention is to provide a shift fork assembly for a power transmission unit of a vehicle, which comprises a plurality of rolling elements adapted to restrict wear and tear of shift fork and synchronizer sleeve when the vehicle is going down the gradient with engine in non-operative condition.
[009] A further another object of an embodiment of this invention is to provide a shift fork assembly for a power transmission unit of a vehicle, which increases the fuel efficiency of the vehicle due to reduced frictional losses in the power transmission unit.
[0010] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0011] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0012] FIG. 1 depicts an exploded view of a shift fork assembly for a power transmission unit, according to a first embodiment of the invention as disclosed herein;
[0013] FIG. 2 depicts a perspective view of the shift fork assembly for the power transmission unit, according to the first embodiment of the invention as disclosed herein;
[0014] FIG. 3 depicts a cross-sectional view of a portion of the shift fork assembly along the line A-A of fig. 2, according to the first embodiment of the invention as disclosed herein;
[0015] FIG. 4 depicts a perspective view of a shift fork of the shift fork assembly, according to the first embodiment of the invention as disclosed herein;
[0016] FIG. 5 depicts a cross-sectional view of a portion of the shift fork of the shift fork assembly, according to the first embodiment of the invention as disclosed herein;
[0017] FIG. 6 depicts a perspective view of a holding element of the shift fork assembly, according to the first embodiment of the invention as disclosed herein;
[0018] FIG. 7 depicts a perspective view of a rolling element of the shift fork assembly, according to the first embodiment of the invention as disclosed herein;
[0019] FIG. 8 depicts a cross-sectional view of a portion of the power transmission unit, according to the first embodiment of the invention as disclosed herein;
[0020] FIG. 9 depicts an exploded view of a shift fork assembly for a power transmission unit, according to a second embodiment of the invention as disclosed herein;
[0021] FIG. 10 depicts a perspective view of the shift fork assembly for the power transmission unit, according to the second embodiment of the invention as disclosed herein;
[0022] FIG. 11 depicts a cross-sectional view of a portion of the shift fork assembly, according to the second embodiment of the invention as disclosed herein;
[0023] FIG. 12 depicts a perspective view of a portion of a shift fork of the shift fork assembly, according to the second embodiment of the invention as disclosed herein;
[0024] FIG. 13 depicts a perspective view of a holding element of the shift fork assembly, according to the second embodiment of the invention as disclosed herein;
[0025] FIG. 14 depicts a perspective view of a portion of a shift fork assembly for a power transmission unit, according to a third embodiment of the invention as disclosed herein; and
[0026] FIG. 15 depicts a cross-sectional view of the portion of the shift fork assembly, according to the third embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0027] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0028] The embodiments herein achieve a shift fork assembly for a power transmission unit of at least one of a vehicle, a machine and the like, which comprises a plurality of rolling elements adapted to restrict wear and tear of shift fork and synchronizer sleeve thereby increasing the life of the shift fork and the synchronizer sleeve. Referring now to the drawings, and more particularly to FIGS. 1 through 15, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0029] FIG. 8 depicts a cross-sectional view of a portion of a power transmission unit 10, according to the first embodiment of the invention as disclosed herein. In the first embodiment, the power transmission unit 10 includes a plurality of shift fork assemblies 100, a plurality of synchronizer assemblies S, a plurality of gears (not shown), a plurality of shafts (not shown), a gear shift lever (not shown) and may include other standard components as present in standard power transmission unit (gear box assembly). For the purpose of this description and ease of understanding, each shift fork assembly 100 in the power transmission unit 10 is explained herein below with reference to power transmission unit 10 of a vehicle. It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in a power transmission unit (gear box assembly) of a machine and the like, or any other systems using power transmission unit (gear box assembly). In an embodiment, the power transmission unit 10 is at least one of a manual transmission unit and an automated manual transmission unit (AMT). It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in any other power transmission unit of the vehicle or any other systems/machines using power transmission unit (gear box assembly).
[0030] FIG. 1 depicts an exploded view of the shift fork assembly 100 for the power transmission unit 10, according to the first embodiment of the invention as disclosed herein. In the first embodiment, each shift fork assembly 100 includes a shift fork 102 (as shown in fig. 1 to fig. 5 and fig. 8), a plurality of holding elements 104 (as shown in fig. 1, fig. 2, fig. 3, fig. 6 and fig. 8), a plurality of rolling elements 106 (as shown in fig. 1, fig. 2, fig. 3, fig 7 and fig. 8) and a plurality of resilient means 108 (as shown in fig. 1, fig. 3 and fig. 8).
[0031] FIG. 4 depicts a perspective view of a shift fork 102 of the shift fork assembly 100, according to the first embodiment of the invention as disclosed herein. FIG. 5 depicts a cross-sectional view of a portion of the shift fork 102 of the shift fork assembly 100, according to the first embodiment of the invention as disclosed herein. The shift fork 102 of each shift fork assembly 100 is used to move corresponding synchronizer sleeve R (as shown in fig. 8) of corresponding synchronizer assembly S to engage or disengage corresponding gear (not shown) in the power transmission unit 10 on engagement of the gear shift lever (not shown). The shift fork 102 of each shift fork assembly 100 includes a plurality of lugs 102a. In the first embodiment, each lug 102a of the shift fork 102 defines a plurality of rolling and resilient member receiving portions 102b. Each rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 defining a first portion 102f adapted to receive a portion of corresponding rolling element 106; a second portion 102s opposite to the first portion 102f, the second portion102s adapted to receive a portion of corresponding another rolling element 106; and an intermediate portion 102i between the first portion 102f and the second portion 102s, the intermediate portion 102i adapted to receive corresponding resilient means 108. Each rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 is at least a longitudinal groove.
[0032] FIG. 6 depicts a perspective view of a holding element 104 of the shift fork assembly 100, according to the first embodiment of the invention as disclosed herein. In the first embodiment, each holding element 104 of each shift fork assembly 100 is used to hold a plurality of corresponding rolling elements 106 of corresponding shift fork assembly 100 in a predetermined position. In the first embodiment, each holding element 104 of each shift fork assembly 100 is connected to corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. In the first embodiment, each holding element 104 of each shift fork assembly 100 includes a plurality of first portions 104a and a plurality of second portions 104. Each first portion 104a of corresponding holding element 104 defining a plurality of rolling member receiving portions 104d. Each rolling member receiving portion 104d of corresponding first portion 104a of each holding element 104 adapted to receive a portion of corresponding rolling element 106 thereby holding corresponding rolling element 106 in a predetermined position. Each rolling member receiving portion 104d of corresponding first portion 104a of each holding element 104 is at least an opening. Each second portion 104b of corresponding holding element 104 is extending between corresponding end of corresponding first portion 104a of corresponding holding element 104, where each first portion 104a and each second portion 104b of corresponding holding element 104 defines a shift fork lug receiving portion 104c adapted to receive corresponding lug 102a of the shift fork 102. The shift fork lug receiving portion 104a of each holding element 104 is at least an opening.
[0033] FIG. 7 depicts a perspective view of a rolling element 106 of the shift fork assembly 100, according to the first embodiment of the invention as disclosed herein. In the first embodiment, each rolling element 106 of each shift fork assembly 100 is adapted to restrict wear and tear of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve R of corresponding synchronizer assembly S. A portion of each rolling element 106 of corresponding shift fork assembly 100 adapted to be engaged to corresponding end of corresponding resilient means 108 of corresponding shift fork assembly 100. Each rolling element 106 of corresponding shift fork assembly 100 is movably connected to corresponding rolling member receiving portion 104d of corresponding first portion 104a of corresponding holding element 104 of corresponding shift fork assembly 100. A portion of each rolling element 106 of corresponding shift fork assembly 100 is disposed external to corresponding first portion 104a of corresponding holding element 104 of corresponding shift fork assembly 100 and engaged to corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S thereby enabling each rolling element 106 of corresponding shift fork assembly 100 to roll on corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S during operation of the power transmission unit 10. Each rolling element 106 of corresponding shift fork assembly 100 defines a ball shape configuration.
[0034] In the first embodiment, corresponding end of each resilient means 108 of each shift fork assembly 100 is adapted to provide a predefined force to corresponding rolling element 106 of corresponding shift fork assembly 100 to engage corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S. Each resilient means 108 of each shift fork assembly 100 is received by the intermediate portion 102i of corresponding rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. In the first embodiment, each resilient means 108 of each shift fork assembly 100 is at least a spring.
[0035] Each synchronizer assembly S is used for smooth engagement or dis-engagement of corresponding gear (not shown) in the power transmission unit 10. Each synchronizer assembly S includes a synchronizer sleeve R (as shown in fig. 8), a hub and may include other standard components as present in standard synchronizer unit of standard power transmission unit (gear box assembly).
[0036] The plurality of gears (not shown) is used to transmit the torque from an input shaft (not shown) to an output shaft (not shown) of the power transmission unit 10.
[0037] The assembly of each shift fork assembly 100 of the power transmission unit 10 is as follows. Each resilient means 108 of corresponding shift fork assembly 100 is provided to the intermediate portion 102i of corresponding rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. Thereafter, corresponding rolling element 106 is provided to the first portion 102f of corresponding rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100 to engage corresponding end of corresponding resilient means 108 of corresponding shift fork assembly 100. Thereafter, corresponding another rolling element 106 is provided to the second portion 102s of corresponding rolling and resilient member receiving portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100 to engage corresponding end of corresponding resilient means 108 of corresponding shift fork assembly 100. Thereafter, each holding element 104 of corresponding shift fork assembly 100 is connected to corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100.
[0038] The configuration of shift fork assemblies 100 in the power transmission unit 10 restricts wear and tear of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S thereby increasing the life of shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve R of corresponding synchronizer assembly S. Further, the aforementioned configuration of the shift fork assembly 100 in the power transmission unit 10 has less friction and less heat generation between each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S due to rolling of corresponding rolling elements 106 on corresponding portion of the synchronizer sleeve R of corresponding synchronizer assembly S. Therefore, a shift fork assembly 100 for a power transmission unit 10, which restricts wear and tear of each lug 102a of the shift fork 102 and corresponding portion of the synchronizer sleeve R, is provided for at least one of a vehicle, a machine and the like.
[0039] FIG. 9 depicts an exploded view of a shift fork assembly 100 for a power transmission unit, according to a second embodiment of the invention as disclosed herein. FIG. 10 depicts a perspective view of the shift fork assembly 100 for the power transmission unit, according to the second embodiment of the invention as disclosed herein. In the second embodiment, the power transmission unit (not shown) includes a plurality of shift fork assemblies 100, a plurality of synchronizer assemblies (not shown), a plurality of gears (not shown), a plurality of shafts (not shown), a gear shift lever (not shown) and may include other standard components as present in standard power transmission unit (gear box assembly). For the purpose of this description and ease of understanding, each shift fork assembly 100 in the power transmission unit (not shown) is explained herein below with reference to power transmission unit (not shown) of a vehicle. It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in a power transmission unit of a machine and the like, or any other systems using power transmission unit (gear box assembly). In an embodiment, the power transmission unit (not shown) is at least one of a manual transmission unit and an automated manual transmission unit (AMT). It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in any other power transmission unit of the vehicle or any other systems/machines using power transmission unit (gear box assembly).
[0040] In the second embodiment, each shift fork assembly 100 includes a shift fork 102, a plurality of holding elements 104, a plurality of rolling elements 106 and a plurality of locking elements 108.
[0041] FIG. 12 depicts a perspective view of a portion of a shift fork 102 of the shift fork assembly 100, according to the second embodiment of the invention as disclosed herein. The shift fork 102 of each shift fork assembly 100 is used to move corresponding synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) to engage or disengage corresponding gear (not shown) in the power transmission unit (not shown) on engagement of the gear shift lever (not shown). The shift fork 102 of each shift fork assembly 100 includes a plurality of lugs 102a (as shown in fig. 9, fig. 11 and fig. 12). Each lug 102a of the shift fork 102 having a plurality of side portions 102b (as shown in fig. 9 and fig. 12) and a plurality of locking member receiving portion 102c. In the second embodiment, each side portion 102b of corresponding lug 102a of the shift fork 102 defining a plurality of rolling member receiving portion 102d. Each rolling member receiving portion 102d of corresponding side portion 102b of corresponding lug 102a of the shift fork 102 adapted to receive a portion of corresponding rolling element 106. A predefined space is provided between each rolling element 106 and each rolling member receiving portion 102d of corresponding side portion 102b of each lug 102a of shift fork 102 thereby facilitating a rolling movement of corresponding rolling element 106 on corresponding portion of synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Each rolling member receiving portion 102d of corresponding side portion 102b of corresponding lug 102a of the shift fork 102 is at least a half round opening. Each locking member receiving portions 102c of corresponding lug 102a of the shift fork 102 is adapted to receive corresponding locking element 108 therein to engage corresponding holding element 104 to corresponding side portion 102b of each lug 102a of the shift fork 102. Each locking member receiving portion 102c of corresponding lug 102a of the shift fork 102 is at least an opening. Each locking member receiving portion 102c of corresponding lug 102a of the shift fork 102 is disposed transverse to the each side portion 102b of corresponding lug 102a of the shift fork 102.
[0042] FIG. 13 depicts a perspective view of a holding element 104 of the shift fork assembly 100, according to the second embodiment of the invention as disclosed herein. In the second embodiment, each holding element 104 of each shift fork assembly 100 is used to hold a plurality of corresponding rolling elements 106 of corresponding shift fork assembly 100 in a predetermined position. In the second embodiment, each holding element 104 of each shift fork assembly 100 is connected to corresponding side portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. In the second embodiment, each holding element 104 of each shift fork assembly 100 having a plurality of rolling member receiving portions 104a and a plurality of locking member receiving portions (not shown). Each rolling member receiving portion 104a of each holding element 104 of corresponding shift fork assembly 100 is adapted to receive a portion of corresponding rolling element 106 thereby holding corresponding rolling element 106 in a predetermined position. Each rolling member receiving portion 104a of each holding element 104 of corresponding shift fork assembly 100 is at least an opening. Each locking member receiving portion (not shown) of each holding element 104 of corresponding shift fork assembly 100 is adapted to receive corresponding end of corresponding locking element 108. Each locking member receiving portion (not shown) of each holding element 104 of corresponding shift fork assembly 100 is at least an opening.
[0043] In the second embodiment, each rolling element 106 of each shift fork assembly 100 is adapted to restrict wear and tear of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Each rolling element 106 of each shift fork assembly 100 is movably connected to corresponding rolling member receiving portion 104a of corresponding holding element 104 of corresponding shift fork assembly 100. A portion of each rolling element 106 of corresponding shift fork assembly 100 is disposed external to corresponding holding element 104 of corresponding shift fork assembly 100 and engaged to corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) thereby enabling each rolling element 106 to roll on corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) during operation of the power transmission unit (not shown). Each rolling element 106 of each shift fork assembly 100 is a solid cylindrical roller. It is also within the scope of the invention to provide a hollow cylindrical roller to restrict the wear and tear of each lug 102a of the shift fork 102 and the synchronizer sleeve (not shown).
[0044] In the second embodiment, each locking element 108 of each shift fork assembly 100 is used to engage/connect corresponding holding element 104 to corresponding side portion102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. Each locking element 108 of each shift fork assembly 100 is received by the locking member receiving portion 102c of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100. In the second embodiment, each locking element 108 of each shift fork assembly 100 is at least one of a rivet pin and a locking pin. It is also within the scope of the invention to provide any other type of locking means to engage/connect corresponding holding element 104 to corresponding side portion102b of corresponding lug 102a of the shift fork 102.
[0045] Each synchronizer assembly (not shown) is used for smooth engagement or dis-engagement of corresponding gear (not shown) in the power transmission unit (not shown). Each synchronizer assembly (not shown) includes a synchronizer sleeve (not shown), a hub and may include other standard components as present in standard synchronizer unit of standard power transmission unit (gear box assembly).
[0046] The plurality of gears (not shown) is used to transmit the torque from an input shaft (not shown) to an output shaft (not shown) of the power transmission unit (not shown).
[0047] The assembly of each shift fork assembly 100 of the power transmission unit (not shown) is as follows. Each rolling element 106 of each shift fork assembly 100 is provided to corresponding rolling member receiving portion 104a of corresponding holding element 104 of corresponding shift fork assembly 100. Thereafter, each holding element 104 with corresponding rolling element 106 in assembled condition is connected to corresponding side portion 102b of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 through corresponding plurality of locking elements 108 of corresponding shift fork assembly 100.
[0048] The configuration of shift fork assemblies 100 in the power transmission unit (not shown) restricts wear and tear of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) thereby increasing the life of shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Further, the aforementioned configuration of the shift fork assembly 100 in the power transmission unit 10 has less friction and less heat generation between each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) due to rolling of corresponding rolling elements 106 on corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Therefore, a shift fork assembly 100 for a power transmission unit 10, which restricts wear and tear of each lug 102a of the shift fork 102 and corresponding portion of the synchronizer sleeve (not shown), is provided for at least one of a vehicle, a machine and the like.
[0049] FIG. 14 depicts a perspective view of a portion of a shift fork assembly 100 for a power transmission unit, according to a third embodiment of the invention as disclosed herein. In the third embodiment, the power transmission unit (not shown) includes a plurality of shift fork assemblies 100, a plurality of synchronizer assemblies (not shown), a plurality of gears (not shown), a plurality of shafts (not shown), a gear shift lever (not shown) and may include other standard components as present in standard power transmission unit (gear box assembly). For the purpose of this description and ease of understanding, each shift fork assembly 100 in the power transmission unit (not shown) is explained herein below with reference to power transmission unit (not shown) of a vehicle. It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in a power transmission unit of a machine and the like, or any other systems using power transmission unit (gear box assembly). In an embodiment, the power transmission unit (not shown) is at least one of a manual transmission unit and an automated manual transmission unit (AMT). It is also within the scope of the invention to use/implement the components of each shift fork assembly 100 in any other power transmission unit of the vehicle or any other systems/machines using power transmission unit (gear box assembly).
[0050] In the third embodiment, each shift fork assembly 100 includes a shift fork 102 and a plurality of rolling elements 104.
[0051] The shift fork 102 of each shift fork assembly 100 is used to move corresponding synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) to engage or disengage corresponding gear (not shown) in the power transmission unit (not shown) on engagement of the gear shift lever (not shown). The shift fork 102 of each shift fork assembly 100 includes a plurality of lugs 102a (as shown in fig. 14 and fig. 15). Each lug 102a of the shift fork 102 defining a rolling member receiving portion 102b (as shown in fig. 14 and fig. 15) adapted to receive an intermediate portion 104c (as shown in fig. 15) of at least one corresponding rolling element 104. The rolling member receiving portion 102b of each lug 102a of the shift fork 102 is at least an opening.
[0052] In the third embodiment, each rolling element 104 of corresponding shift fork assembly 100 is used to restrict wear and tear of each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Each rolling element 104 of each shift fork assembly 100 having a first portion 104a (as shown in fig. 15), a second portion 104b (as shown in fig. 15) opposite to the first portion 104a and an intermediate portion 104c (as shown in fig. 15) between the first portion 104a and the second portion 104b. Each rolling element 104 of corresponding shift fork assembly 100 is movably connected to the rolling member receiving portion 102b of corresponding lug 102a of the shift fork 102 of corresponding shift fork assembly 100 by swaging process. The first portion 104a and the second portion 104b of each rolling element 104 of corresponding shift fork assembly 100 is disposed external to corresponding lug 102a of said shift fork 102 of corresponding shift fork assembly 100 and engaged to corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) thereby enabling each rolling element 104 to roll on corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) during operation of the power transmission unit (not shown). Each rolling element 104 of each shift fork assembly 100 defines a ball shape configuration. It is also within the scope of the invention to provide each rolling element 104 in any other shape and size.
[0053] Each synchronizer assembly (not shown) is used for smooth engagement/dis-engagement of corresponding gear (not shown) in the power transmission unit (not shown). Each synchronizer assembly (not shown) includes a synchronizer sleeve (not shown), a hub and may include other standard components as present in standard synchronizer unit of standard power transmission unit (gear box assembly).
[0054] The plurality of gears (not shown) is used to transmit the torque from an input shaft (not shown) to an output shaft (not shown) of the power transmission unit (not shown)
[0055] The configuration of shift fork assemblies 100 in the power transmission unit (not shown) restricts wear and tear each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) thereby increasing the life of shift fork 102 of corresponding shift fork assembly 100 and the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Further, the aforementioned configuration of the shift fork assembly 100 in the power transmission unit (not shown) has less friction and less heat generation between each lug 102a of the shift fork 102 of corresponding shift fork assembly 100 and corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown) due to rolling of corresponding rolling elements 104 on corresponding portion of the synchronizer sleeve (not shown) of corresponding synchronizer assembly (not shown). Therefore, a shift fork assembly 100 for a power transmission unit 10, which restricts wear and tear of each lug 102a of the shift fork 102 and corresponding portion of the synchronizer sleeve, is provided for at least one of a vehicle, a machine and the like.
[0056] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:CLAIMS
We claim,
1. A shift fork assembly 100 for a power transmission unit 10 comprising a synchronizer assembly S, said shift fork assembly 100 comprising:
a plurality of resilient means 108;
a plurality of rolling elements 106, a portion of each of said rolling element 106 adapted to be engaged to corresponding end of corresponding said resilient means 108;
a shift fork 102 having a plurality of lugs 102a, each of said lug 102 defining a plurality of rolling and resilient member receiving portions 102b, each of said rolling and resilient member receiving portion 102b of corresponding said lug 102 defining a first portion 102f adapted to receive a portion of corresponding said rolling element 106; a second portion 102s opposite to the first portion 102f, the second portion 102s adapted to receive a portion of corresponding said another rolling element 106; and an intermediate portion 102i between the first portion 102f and the second portion 102s, the intermediate portion 102i adapted to receive corresponding said resilient means 108; and
a plurality of holding elements 104 adapted to be connected to corresponding lug 102a of said shift fork 102, each of said holding element 104 having a plurality of first portions 104a, each of said first portion 104a of corresponding said holding element 104 defining a plurality of rolling member receiving portion 104d, each of said rolling member receiving portion 104d of corresponding said first portion 104a of corresponding said holding element 104 adapted to receive a portion of corresponding said rolling element 106 thereby holding corresponding said rolling element 106 in a predetermined position; and a plurality of second portions 104b extending between corresponding end of corresponding said first portion 104a, where each of said first portion 104a and each of said second portion 104b defines a shift fork lug receiving portion 104c adapted to receive corresponding lug 102a of said shift fork 102,
wherein
each of said rolling element 106 is movably connected to corresponding rolling member receiving portion 104d of corresponding first portion 104a of corresponding said holding element 104;
corresponding end of each of said resilient means 108 is adapted to provide a predefined force to corresponding said rolling element 106 to engage corresponding portion of a synchronizer sleeve R of said synchronizer assembly S; and
a portion of each of said rolling element 106 is disposed external to corresponding first portion 104a of corresponding said holding element 104 and engaged to corresponding portion of the synchronizer sleeve R of said synchronizer assembly S thereby enabling each of said rolling element 106 to roll on corresponding portion of the synchronizer sleeve R of said
synchronizer assembly S during operation of said power transmission unit 10.

2. The shift fork assembly 100 as claimed in claim 1, wherein each of said resilient means 108 is at least a spring.

3. The shift fork assembly 100 as claimed in claim 1, wherein each of said rolling element 106 defines a ball shape configuration.

4. The shift fork assembly 100 as claimed in claim 1, wherein each of said rolling and resilient member receiving portion 102b of each of said lug 102a of said shift fork 102 is at least a longitudinal groove.

5. The shift fork assembly 100 as claimed in claim 1, wherein the shift fork lug receiving portion 104a of each of said holding element 104 is at least an opening.

6. The shift fork assembly 100 as claimed in claim 4, wherein each of said rolling member receiving portion 104d of corresponding first portion 104a of each of said holding element 104 is at least an opening.

7. The shift fork assembly 100 as claimed in claim 1 is configured to be provided to said power transmission unit 10 of at least one of a vehicle and a machine.

8. A shift fork assembly 100 for a power transmission unit comprising a synchronizer assembly, said shift fork assembly 100 comprising:
a plurality of rolling elements 106;
a plurality of locking elements 108;
a plurality of holding elements 104, each of said holding element 104 defining a plurality of rolling member receiving portions 104a, each of said rolling member receiving portion 104a of corresponding said holding element 104 adapted to receive a portion of corresponding said rolling element 106 thereby holding corresponding said rolling element 106 in a predetermined position; and a plurality of locking member receiving portions, each of said locking member receiving portion of corresponding said holding element 104 adapted to receive corresponding end of corresponding said locking element 108; and
a shift fork 102 having a plurality of lugs 102a, each of said lug 102a having a plurality of side portions 102b, each of said side portion 102b of corresponding said lug 102a defining a plurality of rolling member receiving portion 102d, each of said rolling member receiving portion 102d of corresponding said side portion 102b of corresponding lug 102a adapted to receive a portion of corresponding said rolling element 106; and a plurality of locking member receiving portions 102c, each of said locking member receiving portion 102c of corresponding said side portion 102b of corresponding lug 102a adapted to receive corresponding said locking element 108 therein to engage corresponding said holding element 104 to corresponding side portion 102b of corresponding said lug 102a,
wherein
each of said holding element 104 is connected to corresponding side portion 102b of each of said lug 102a of said shift fork 102;
each of said rolling element 106 is movably connected to corresponding rolling member receiving portion 104a of corresponding said holding element 104;
a portion of each of said rolling element 106 is disposed external to corresponding said holding element 104 and engaged to corresponding portion of a synchronizer sleeve of said synchronizer assembly thereby enabling each of said rolling element 106 to roll on corresponding portion of the synchronizer sleeve of said synchronizer assembly during operation of said power transmission unit; and
a predefined space is provided between each of said rolling element 106 and each of said rolling member receiving portion 102d of corresponding side portion 102b of each of said lug 102a of said shift fork 102 thereby facilitating a rolling movement of corresponding said rolling element 106 on corresponding portion of synchronizer sleeve of said synchronizer assembly.

9. The shift fork assembly 100 as claimed in claim 8, wherein each of said rolling element 106 is at least a solid cylindrical roller.

10. The shift fork assembly 100 as claimed in claim 8, wherein each of said locking element 108 is at least one of a rivet pin and a locking pin.

11. The shift fork assembly 100 as claimed in claim 8, wherein each of said rolling member receiving portion 104a of each of said holding element 104 is at least an opening.

12. The shift fork assembly 100 as claimed in claim 8, wherein each of said locking member receiving portion of each of said holding element 104 is at least an opening.

13. The shift fork assembly 100 as claimed in claim 8, wherein each of said rolling member receiving portion 102d of corresponding side portion 102b of each of said lug 102a of said shift fork 102 is at least a half round opening.
14. The shift fork assembly 100 as claimed in claim 8, wherein each of said locking member receiving portion 102c of each of said lug 102a of said shift fork 102 is at an opening.

15. The shift fork assembly 100 as claimed in claim 8 is configured to be provided to said power transmission unit of at least one of a vehicle and a machine.

16. A shift fork assembly 100 for a power transmission unit comprising a synchronizer assembly, said shift fork assembly comprising:
a plurality of rolling elements 104, each of said rolling element 104 having a first portion 104a, a second portion 104b opposite to the first portion 104a and an intermediate portion 104c between the first portion 104a and the second portion 104b; and
a shift fork 102 having a plurality of lugs 102a, each of said lug 102a defining a rolling member receiving portion 102b adapted to receive the intermediate portion 104c of at least one corresponding said rolling element 104,
wherein
each of said rolling element 104 is movably connected to the rolling member receiving portion 102b of corresponding lug 102a of said shift fork 102; and
the first portion 104a and the second portion 104b of each of said rolling element 104 is disposed external to corresponding lug 102a of said shift fork 102 and engaged to corresponding portion of a synchronizer sleeve of said synchronizer assembly thereby enabling each of said rolling element 104 to roll on corresponding portion of the synchronizer sleeve of said synchronizer assembly during operation of said power transmission unit.

17. The shift fork assembly 100 as claimed in claim 16, wherein each of said rolling element 104 is movably connected to the rolling member receiving portion 102b of corresponding lug 102a of said shift fork 102 by swaging process.

18. The shift fork assembly 100 as claimed in claim 16, wherein the rolling member receiving portion 102b of each lug 102a of said shift fork 102 is at least an opening.

19. The shift fork assembly 100 as claimed in claim 16, wherein each of said rolling element 104 defines a ball shape configuration.