Claims:We Claim:
1. A parking lock assembly (108) for a vehicle transmission comprising
a resilient member (306); said resilient member (306) is operatively connected to an engaging member (216), said engaging member (216) is configured to engage with an output gear (217) coupled to an input shaft assembly (213);
a cam lock (308), said cam lock (308) is configured to actuate said engaging member (216) in response to a user input;
wherein said resilient member (306) is configured to keep said engaging member (216) in a predetermined position when said vehicle is in predetermined state.

2. The parking lock assembly (108) for a vehicle transmission as claimed in claim 1, wherein said predetermined position includes a disengaged position when the vehicle is in motion.

3. The parking lock assembly (108) for a vehicle transmission as claimed in claim 1, wherein said input shaft assembly (213) is parallel to a countershaft assembly (215).

4. The parking lock assembly (108) for a vehicle transmission as claimed in claim 3, wherein said countershaft assembly (215) is configured to receive said engaging member (216) and a bush member (307), said bush member (307) is configured to have a groove (311) of predetermined dimension adapted to retain said resilient member (307).

5. The parking lock assembly (108) as claimed in claim 1, wherein said engaging member (216) comprising of
a toothed portion configured to engage with said output gear (217),
an opening (309) adapted to receive a portion of a counter shaft (303), and
a predetermined counterweight (216C) at one of its ends adapted to move said engaging member (216) based on user input.

6. The parking lock assembly (108) for a vehicle transmission as claimed in claim 5, wherein said countershaft (303) is configured to have a groove (310) of predetermined dimension adapted to receive a circlip (304) configured to arrest the axial movement of the engaging member (216).

7. The parking lock assembly (108) for a vehicle transmission as claimed in claim 1, wherein said cam lock (308), disposed between said output gear (217) and said engaging member (216), is rotatably mounted and supported by a housing (103).

8. The parking lock assembly (108) for a vehicle transmission as claimed in claim 1, wherein said cam lock (308) is configured to have plurality of legs (308F, 308S) which facilities the engagement and disengagement of the engaging member (216) with the output gear (217).

9. The parking lock assembly (108) for a vehicle transmission as claimed in claim 8, wherein said legs (308F, 308S) comprises of a pair of first and second leg, said first leg (308F) of said cam lock (308) engageable with the primary end (216P) of the engaging member (216) thereby to rotate the engaging member (216) in a predetermined direction to engage it with the output gear (217).

10. The parking lock assembly (108) for a vehicle transmission as claimed in claim 8, wherein said second leg (308S) of said cam lock (308) facilities the disengagement of the engaging member (216) from the output gear (217) based on user inputs.

11. The parking lock assembly (108) for a vehicle transmission as claimed in claim 1, wherein said output gear (217) is configured to have predetermined involute tooth profile adapted to have a larger width as compared to a tooth profile, which ensure a predetermined gap between said toothed portion of engaging member (216) and tooth portion of said output gear (217) to ensure ease of disengagement.

12. A powertrain (101) for a vehicle comprises of:
a housing (103) enclosing a multispeed transmission (201), said housing includes a pair of left and right side cover (103L, 103R), said left side cover (103L) configured to have plurality of sidewalls (104) extending from an outer surface (105) of said left side cover (103L) in the lateral direction (C-C’) of the powertrain (101), an interior surface (106) of said sidewalls (104) and the outer surface (105) of the left side cover (103L) defining an interior volume (V), said interior volume (V) is adapted to receive a parking lock assembly (108) as claimed in any of preceding claims.

13. The powertrain (101) for a vehicle as claimed in claim 12, wherein an end surface (107) of the sidewalls (104) is covered by a cover member (109), said cover member (109) is secured to the end surface (107) of the sidewalls (104) to ensure leak-proof lubrication of the parking lock assembly (108) during all driving conditions.

14. A powertrain for a vehicle comprises of at least three driving mode actuated by an actuating means, said driving modes comprising of:
a forward driving mode, said forward driving mode is activated when a hand lever is in a position D, wherein under said forward driving mode a predetermined force exerted by a resilient member (306) on an engaging member (216) to keep said engaging member (216) at disengaged position such that a primary end (216P) of said engaging member (216) rest on a stopper (401) to restricts the rotational movement of said resilient member (306);
a neutral mode, said neutral mode is activated when said hand lever is in a position N, wherein under said neutral mode with aid of a predetermined counterweight (216C) provided at a secondary end (216S) of said engaging member (216), said engaging member (216) rotates in a predetermined direction such that said secondary end (216S) of said engaging member (216) rests on a cushion member (218) and said primary end (216P) of said engaging member (216) comes in contact with a first leg (308F) of a cam lock (308); and
a parking mode, said parking mode is activated when said hand lever is in a position P, wherein under said parking mode said cam lock (308) rotates said engaging member (216) in said predetermined direction to engage with an output gear (217) such that said first leg (308F) of the cam lock (308) pushes said primary end (216P) of said engaging member (216) in the predetermined direction to engage a tooth portion of said engaging member (216) with an output gear (217) to arrests the rotational movement of said output gear (217) and thereby an input shaft (301). , Description:TECHNICAL FIELD
[0001] The present subject matter relates to a vehicle. More particularly, to a parking lock assembly for a vehicle.

BACKGROUND
[0002] Typically, an automatic transmission is provided with a parking lock mechanism. The parking lock mechanism prevents the unintentional movement of a vehicle. This is achieved by locking a transmission output shaft, which is rotationally connected to the drive wheels.
[0003] The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The present invention is described with reference to an exemplary embodiment of a powertrain with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
[0005] Figure 1 illustrates a perspective view of the powertrain (101) and a localized enlarged view of the powertrain (101) where a cover member (109) is omitted from the figure as per embodiment, in accordance with one example of the present subject matter.
[0006] Figure 2 illustrates a side view and top cut section view across A-A’ plane of the powertrain (101) configured to have a multispeed transmission assembly (201) for the vehicle, in accordance with one example of the present subject matter.
[0007] Figure 3a illustrates a perspective view and a localized exploded view of the powertrain (101) where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter.
[0008] Figure 3b illustrates a localized enlarged top cut view of the powertrain (101) across A-A’ axis where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter.
[0009] Figure 4a illustrates a side view of a parking lock assembly (108) of the powertrain (101) in a disengaged position where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter.
[00010] Figure 4b illustrates a side view of the parking lock assembly (108) of the powertrain (101) in a neutral position where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter.
[00011] Figure 4c illustrates a side view of the parking lock assembly (108) of the powertrain (101) in engaged position and a localized view of an output gear and engaging member in engaged position where few parts are omitted from the figures, in accordance with one example implementation of the present subject matter.

DETAILED DESCRIPTION
[00012] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder.
[00013] Typically, the vehicles configured to have an automatic transmission provide different gear ratios that are different from one another. Precisely, several driving gears formed as forward gears and at least one driving gear is formed as a reverse gear. The automatic transmission is configured to adjust the gear ratios as a function of a vehicle operating state. The vehicle operating state includes torque, rotational speed, particularly of a prime mover. Generally, the automatic transmission is actuated by a lever. The user of the vehicle can select the engagement by shifting the lever to a certain setting. Generally, the lever can be arranged to a park setting “P”, a reverse setting “R”, a forward driving setting “F or D”, and a neutral setting “N”.
[00014] In order to safely set the vehicle in the park setting of the lever, and to prevent the rolling of the vehicle on incline roads the vehicle is configured with a parking lock mechanism. The parking lock mechanism is fitted into the vehicle with the automatic transmission to lock up a transmission output shaft and drive wheel(s) from rotating.
[00015] The parking lock mechanism assembly includes a parking pawl, plurality of gears, and one or more notched ring. The parking pawl engages with the notched ring that is attached to a transmission output shaft based on user input.
[00016] Generally, the vehicle is provided with both emergency brake and parking lock mechanism. The ideal practice is to actuate the emergency brake first before actuating the parking lock mechanism. However, deviation from ideal practice severely affects the durability of the parking lock mechanism. More specifically, if the vehicle is parked on the incline road, an undue stress is placed on the parking pawl and its associated parts. Because the weight of the vehicle rest on the parking pawl. Overtime, when parking pawl is used in above manner, it wears out and becomes weak leading to premature failure, further leading to frequent service of the vehicle. During service, replacing a broken parking pawl involves removing of the automatic transmission from the vehicle in order to access the parking pawl and replace it.
[00017] Further, parking on the incline road without using emergency brake before actuating the parking pawl mechanism can cause the lever to become stuck in the park position “P”. This is due to the weight of the vehicle being placed on the parking pawl instead of the emergency brake. In other words, the vehicle on the incline road exerts a torque due to its weight on the notched ring, and the torque is transmitted to the parking pawl. The force between the notched ring and the parking pawl can be very high based on the incline road which can make it difficult to disengage. To disengage the parking lock mechanism, the force required should be higher than the friction force between the notched ring and parking pawl. Therefore, the resulting forces can cause excessive noise and vibration, which can panic the occupants of the vehicle. As a result, in order to free the lever, the user need to push the vehicle slightly uphill on the incline road to take the weight off the parking pawl which is practically not feasible. This phenomenon severely affects the driving comfort and leads to customer dissatisfaction.
[00018] Furthermore, even the vehicles with an electric parking brake require either a dedicated failsafe hydraulic or electric park brake which automatically engages the parking lock in the event of a failure of the on-board electrical system. However, the construction of such automatic parking lock assemblies is complex and includes several expensive components to ensure the safety aspect related with the parking function in all conditions. This leads to increase in the number of part count and weight of the vehicle.
[00019] Moreover, it is observed that the parking pawl engaging with notched ring at higher speed is a big concern for the wheel lock and loss of control of the vehicle. This unpredictable stop may cause higher stresses in the parking lock mechanism and other transmission components, and can eventually cause wear, fatigue, and vehicle damage.
[00020] Therefore, there is a need for improved parking lock assembly for a vehicle transmission which overcomes all the above problems and other problems of known art.
[00021] To this end, it is an object of the present invention is to provide a simple, efficient, durable, cost effective and reliable parking lock assembly for the vehicle transmission.
[00022] It is another object of the present invention to provide a parking lock assembly which is easy to operate even on the incline road.
[00023] According to the present subject matter to attain the above-mentioned objectives, a first characteristic of the present invention is a parking lock assembly for a vehicle transmission comprising a resilient member; said resilient member is operatively connected to an engaging member, said engaging member is configured to engage with a output gear; a cam lock, said cam lock is configured to actuate said engaging member in response to a user input; wherein said resilient member is configured to keep said engaging member in a predetermined position when said vehicle is in predetermined state.
[00024] In addition to the first characteristic, a second characteristic of the present invention is the parking lock assembly for a vehicle transmission wherein said predetermined position includes a disengaged position when the vehicle is in motion.
[00025] In addition to the first characteristic, a third characteristic of the present invention is the parking lock assembly for a vehicle transmission wherein said output gear is installed on an input shaft assembly, said input shaft assembly is parallel to a countershaft assembly.
[00026] In addition to the third characteristic, a fourth characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said countershaft assembly is configured to receive said engaging member and a bush member, said bush member is configured to have a groove of predetermined dimension adapted to retain said resilient member.
[00027] In addition to the first characteristic, a fifth characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said engaging member comprising of a toothed portion is configured to engage with said output gear, an opening adapted to receive a portion of a counter shaft, and a predetermined counterweight at one of its ends adapted to move said engaging member based on user input.
[00028] In addition to the fifth characteristic, a sixth characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said countershaft is configured to have a groove of predetermined dimension adapted to receive a circlip configured to arrest the axial movement of the engaging member.
[00029] In addition to the first characteristic, a seventh characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said cam lock disposed between said output gear and said engaging member is rotatably mounted and supported by a housing.
[00030] In addition to the first characteristic, an eight characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said cam lock is configured to have plurality of legs which facilities the engagement and disengagement of the engaging member with the output gear.
[00031] In addition to the eight characteristic, an ninth characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said legs comprises of a pair of first and second leg, said first leg of said cam lock is engageable with the primary end of the engaging member thereby causing the engaging member to rotate in a predetermined direction to engage it with the output gear.
[00032] In addition to the eight characteristic, a tenth characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said second leg of said cam lock facilities the disengagement of the engaging member from the output gear based on user inputs.
[00033] In addition to the first characteristic, an eleventh characteristic of the present invention is the parking lock assembly for a vehicle transmission, wherein said output gear is configured to have predetermined involute tooth profile. The involute tooth profile adapted to have a larger width as compared to tooth profile. This ensures a predetermined gap between said toothed portion of engaging member and the gear tooth portion of said output gear to ensure ease of disengagement.
[00034] An twelfth characteristic of the present invention is a powertrain for a vehicle which comprises of a housing enclosing a multispeed transmission, said housing includes a pair of left and right side cover, said left side cover is configured to have plurality of sidewalls extending from an outer surface of said left side cover in the lateral direction of the powertrain, an interior surface of said sidewalls and the outer surface of the left side cover defining an interior volume, said interior volume is adapted to receive a parking lock assembly
[00035] In addition to the twelfth characteristic, a thirteenth characteristic of the present invention is the powertrain for the vehicle, wherein an end surface of the sidewalls is covered by a cover member, said cover member is secured to the end surface of the sidewalls to ensure leak-proof lubrication of the parking lock assembly during all driving conditions.
[00036] A fourteenth characteristic of the present invention is a powertrain for a vehicle comprising of at least three driving mode actuated by an actuating means. The driving modes comprising of a forward driving mode, said forward driving mode is activated when said hand lever is in a position D, wherein under said forward driving mode a predetermined force exerted by a resilient member on an engaging member to keep said engaging member at disengaged position such that a primary end of said engaging member rest on a stopper to restricts the rotational movement of said resilient member; a neutral mode, said neutral mode is activated when said hand lever is in a position N, wherein under said neutral mode with aid of a predetermined counterweight provided at a secondary end of said engaging member, said engaging member rotates in a predetermined direction such that said secondary end of said engaging member rests on a cushion member and said primary end of said engaging member comes in contact with a first leg of a cam lock; and a parking mode, said parking mode is activated when said hand lever is in a position P, wherein under said parking mode said cam lock rotates said engaging member in said predetermined direction to engage with an output gear such that said first leg of the cam lock pushes said primary end of said engaging member in the predetermined direction to engage a tooth portion of said engaging member with an output gear to arrests the rotational movement of said output gear and thereby an input shaft.
[00037] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00038] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[00039] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
[00040] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.
[00041] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.
[00042] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.
[00043] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[00044] Figure 1 illustrates a perspective view of a powertrain (101) and a localized enlarged view of the powertrain (101) where a cover member (109) is omitted from the figure as per embodiment, in accordance with one example of the present subject matter. The powertrain (101) comprises of a prime mover (102). As per one implementation, the prime mover (102) includes an electric machine. The prime mover (102) can be of various capacity in order to characterize and calibrate a vehicle to meet various requirements and needs according to the usage pattern of user and/or market segment application. Further, a housing (103) which is attached to the prime mover (102) comprising of a pair of left and right-side cover (103L, 103R). As per one implementation, the left side cover (103L) is configured to have plurality of sidewalls (104) extending from an outer surface (105) of the left side cover (103L) in a lateral direction (C-C’) of the powertrain (101). An interior surface (106) of the sidewalls (104) and the outer surface (105) of the left side cover (103L) define an interior volume (V). The interior volume (V) is adapted to receive a parking lock assembly (108). An end surface (107) of the sidewalls (104) is covered by a cover member (109). The cover member (109) is configured to have one or more threaded aperture (not shown) aligned with one or more internally threaded aperture (110) in the sidewalls (104). An attachment means (111) is inserted through the threaded aperture (not shown) of the cover member (109), and the internally threaded aperture (110) in the sidewalls (104) which secures attachment of the cover member (109) to the end surface (107) of the sidewalls (104). This architecture of the powertrain (101) ensures leak-proof lubrication of the parking pawl assembly (108) during all driving conditions. As per alternative embodiment, the right-side cover (103R) is configured to have plurality of sidewalls (104) along with the parking pawl assembly 108 extending in lateral direction (C-C’) of the powertrain (101).
[00045] Figure 2 illustrates a side view and top cut section view across A-A’ plane of the powertrain (101) configured to have a multispeed transmission assembly (201) for the vehicle, in accordance with one example of the present subject matter. As per one implementation, the multispeed transmission assembly (201) is disposed on a left side (L) of the powertrain (101) extending in the lateral direction (C-C’). Further, as per alternative embodiment the multispeed transmission assembly (201) disposed on the right side (R) of the powertrain (101) extending in the lateral direction (C-C’). The multispeed assembly (201) is operable through a gear shift and select assembly (202). The gear shift and select assembly (202) comprises of at least one actuator (203) coupled with at least one decoupling device (204) through at least one reduction device (205). Further, the gear shift and select assembly (202) comprises at least one gear shift shaft (206). The gear shift shaft (206) is attached to at least one gear shift fork (207). The decoupling device (204) gets the drive from actuator (203) with a reduction of r.p.m (rotation per minute) by the reduction device (205). An output shaft (208) of the decoupling device (204) is configured to have a worm gear profile (209) on at least a portion. The gear shift fork (207) has a rack profile (210) in proximity to an upper end and an hole or opening (not shown) near the upper end through which the gear shift shaft (206) extends. The worm gear profile (209) engages with the rack profile (210) provided on the gear shift fork (207). Hence the worm and rack mechanism makes the gear shift fork (207) to move to and fro which leads to change of system from high torque gearing (211) to low torque gearing (212). The high torque gearing (211) includes high torque input gearing (211I) and high torque output gearing (211O). The high torque input gearing (211I) is engaged with high torque output gearing (211O). The high torque input gearing (211I) is installed on an input shaft assembly (213). The input shaft assembly (213) is adapted to have involute splines (214) at one of its end to fixedly couple with the prime mover (102). The high torque output gearing (211O) is movably installed on a counter shaft assembly (215). The counter shaft assembly (215) is disposed parallel and alongside the input shaft assembly (213). Furthermore, the low torque gearing (212) comprises low torque input gearing (212I) and low torque output gearing (212O). The low torque input gearing (212I) is engaged with low torque output gearing (212O). The low torque input gearing (212I) is installed on the input shaft assembly (213). The low torque output gearing (212O) is movably installed on the counter shaft assembly (215). Further, the powertrain (101) is provided with the parking lock assembly (108). The parking lock assembly (108) comprises of an engaging member (216) and an output gear (217). The engaging member (216) is installed on the countershaft assembly (215). Further, the output gear (217) is installed on the input shaft assembly (213). More specifically, the engaging member (216) is configured to have a primary end (216P) and a secondary end (216S) extending in opposite direction from a pivoted connection P of the engaging member (216) wherein pivot P is coaxial on the countershaft assembly (215). The primary end (216P) is configured to have a toothed portion adapted to engage with a toothed portion of the output gear (217). The secondary end (216S) of the engaging member (216) is configured to have a predetermined counterweight (216C) away from the pivot point. The secondary end (216S) of the engaging member (216) is configured to have predetermined shape. As per one implementation, the secondary end (216S) of the engaging member (216) is gently curved towards a cushion member (218) to ensure smooth disengagement of the engaging member (216) from the output gear (217) when the vehicle is in standstill or at halt condition.
[00046] Figure 3a illustrates a perspective view and a localized exploded view of the powertrain (101) where few parts are omitted from the figure and figure 3b illustrates a localized enlarged top cut view of the powertrain (101) across A-A’ plane in accordance with one example implementation of the present subject matter shown in Fig 2. For sake of brevity both the figure 3a and figure 3b will be discussed together. The output gear (217) is coaxially and securely mounted on the input shaft assembly (213) to rotate therewith. More specifically, the output gear (217) is installed on an input shaft (301). The parking gear (217) is secured to the input shaft (301) using attachment means (302). As per one implementation, the attachment means (302) includes at least one threaded fastener and washer. The input shaft (301) is configured to have an internally threaded aperture (301T). The attachment means (302) is inserted through an opening (217O) of the output gear (217), and the internally threaded aperture (301T) in the input shaft (301) which secures the output gear (217) to the input shaft (301). Further, the engaging member (216) is pivotally or rotatably connected to the counter shaft assembly (215) for engaging and disengaging with the output gear (217). More specifically, the engaging member (216) is configured to have an opening (309) adapted to receive a portion of a counter shaft (303) which is coaxial with countershaft assembly 215. The countershaft (303) is configured to have a groove (310) of predetermined dimension adapted to receive a circlip (304). The circlip (304) is positioned to arrest the axial movement of the engaging member (216). The engaging member (216) provided with an opening (305) adapted to receive one end of a resilient member (306). The resilient member (306) is interference fitted in a groove (311) provided on a bush member (307). The bush member (307) is fixedly secured to a portion of the countershaft (303). Further, between the output gear (217) and engaging member (216), there is arranged a cam lock (308). The cam lock (308) functions to actuate the engaging member (216) in response to the movement of a hand lever (402) (as shown in fig. 4). The cam lock (308) is rotatably mounted and supported by the housing (103) (as shown in figure 1). Further, the cam lock (308) is configured to have plurality of legs (308F, 308S) which facilities the engagement and disengagement of the engaging member (216) with the output gear (217). The legs (308F, 308S) comprises of a pair of first and second leg. The cam lock (308) is contactable with the primary end (216P) of the engaging member (216). The first leg (308F) of cam lock (308) engageable with the primary end (216P) of the engaging member (216) thereby to rotate the engaging member (216) in a predetermined direction to engage it with the output gear (217). However, the second leg (308S) of cam lock (308) facilities the disengagement of the engaging member (216) from the output gear (217) based on user input. Further, the engaging member (216) rotates in predetermined direction based on user inputs. However, when vehicle is stationary or at halt, the secondary end (216S) of the engaging member (216) rests on the cushion member (218).
[00047] Figure 4a illustrates a side view of the parking lock assembly (108) of the powertrain (101) in disengaged position where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter. The powertrain comprises of at least three driving modes. These driving modes are actuated by an actuating means. The driving modes include a forward driving mode, a neutral mode and a parking mode. The forward driving mode can be activated by shifting the hand lever (402) in a position “D”. In this condition, the countershaft (303) rotates along with the bush member (307) and resilient member (306) as a single unit in the predetermined direction. Further, one end of the resilient member (306) is operatively connected to the engaging member (216), at the opening (305), which rotates the engaging member (216) in the same direction. However, the pivotal movement of the engaging member (216) is restricted to a predetermined angular range by a stopper (401). The stopper (401) is provided in the lower half rear end of the left side housing (103L) (as shown in figure 1). Precisely, the primary end (216P) of the engaging member (216) rest on the stopper (401). This phenomenon, restricts the rotational movement of the resilient member (306). Under this condition, the resilient member (306) is held stationary, however the bush member (307) continuously rotates with the countershaft (303). Therefore, a predetermined force exerted by the resilient member (306) on the engaging member (216) keeps the engaging member (216) at disengaged position even if the user unintentionally moves the hand lever (402) in all driving conditions. When vehicle is in motion, the user will not experience any resistance at hand lever (402) because the cam lock (308) is freely rotatable with no contact with the engaging member (216). Therefore, unintentional engagement of the engaging member (216) with the output gear (217) i.e. unintentional activation of parking lock, is assuredly prevented in all driving conditions. Importantly, to ensure efficient thermal management, the parking lock assembly (108) is under continuous lubrication. Further, the resilient member (306) and the bush member (307) are made up of predetermined material to withstand the stress and load experienced during all driving conditions.
[00048] Figure 4b illustrates a side view of the parking lock assembly (108) of the powertrain (101) in a neutral position where few parts are omitted from the figure, in accordance with one example implementation of the present subject matter. The neutral mode is activated when hand lever (402) is shifted to Neutral position “N” by the user. Thereby, the vehicle comes to halt condition. With aid of the predetermined counterweight (216C) provided at secondary end (216S) of the engaging member (216), the engaging member (216) rotates in a predetermined direction. Under this condition i.e. neutral position, the secondary end (216S) of engaging member (216) rests on the cushion member (218) and primary end (216P) of the engaging member (216) comes in contact with the first leg (308F) of the cam lock (308). This thereby enables no engagement of the parking lock assembly in the neutral position N.
[00049] Figure 4c illustrates a side view of the parking lock assembly (108) of the powertrain (101) in engaged position and a localized view of an output gear and engaging member in engaged position where few parts are omitted from the figures, in accordance with one example implementation of the present subject matter. The parking mode is activated when the hand lever (402) is shifted to parking position “P” by the user, thereby the cam lock (308) rotates the engaging member (216) in the predetermined direction to engage with the output gear (217). More specifically, the first leg (308F) of the cam lock (308) pushes primary end (216P) of the engaging member (216) in the predetermined direction. Under this condition, the tooth portion of the engaging member (216) arrests the rotational movement of the output gear (217) and thereby the input shaft (301). The rotation of the engaging member (216) in predetermined direction compresses the cushion member (218) resulting in the energy stored in the cushion member (218). The stored energy facilities the disengagement of the engaging member (216) from the output gear (217) when the hand lever (402) shifts from “P” position to “N” or “D” position. Thereby, reduces the force required to disengage the engaging member (216) when it has to be returned in position D and N. Further, the second leg (308S) of the cam lock (308) facilities the disengagement of the engaging member (216) from the output gear (217) when hand lever return in position D and N. Furthermore, the output gear (217) is configured to have predetermined involute tooth profile. The involute tooth profile adapted to have a larger width as compare to tooth profile. This ensures a predetermined gap between the toothed portion of engaging member (216) and tooth portion of said output gear (217) to ensure ease of disengagement.
[00050] According to above architecture, the primary efficacy of the present invention is that an improved parking lock assembly for use with the vehicle transmission is configured to allow the ease of serviceability. Because the parking lock assembly is configured on the outer surface of the powertrain housing which ensures ease of accessibility while servicing.
[00051] According to above architecture, the primary efficacy of the present invention is that an improved park lock assembly for use with the vehicle transmission, configured to have improved reliability. Because in event of failure of on-board electrical system the user can actuate the improved parking lock assembly and can safely halt the vehicle.
[00052] According to above architecture, the primary efficacy of the present invention is that an improved park lock assembly for use with the vehicle transmission is configured to be simple in construction. More specifically, the improved parking lock assembly eliminates the use of plurality of sensors, actuators and hydraulic systems. This reduces the overall weight and scaling of the powertrain.
[00053] According to above architecture, the primary efficacy of the present invention is that an improved park lock assembly for use with the vehicle transmission is configured to prevent the accidental engagement of the engaging member. The predetermined force exerted by the resilient member keeps the engaging member at disengaged position even if the user unintentionally moves the hand lever in all driving conditions. Under this condition, the user will not experience any resistance at hand lever because the cam lock is freely rotatable with no contact with the engaging member wherein the engaging member rests on the stopper thereby achieving a failsafe solution.
[00054] According to above architecture, the primary efficacy of the present invention is that an improved park lock assembly for use with the vehicle transmission, configured to easily release the engaging member from the parking position even when the vehicle is on inclined road. Because, the predetermined force stored in the cushion member during parking state of the vehicle facilities the disengagement of engaging member from the output gear once user changes selection to N or D mode. Thereby, substantially reducing the force required to disengage the engaging member.
[00055] According to above architecture, the primary efficacy of the present invention is that an improved park lock assembly for use with the vehicle transmission, configured to have the predetermined tooth profile of output gear and engaging member which ensures smoothly and gradual disengagement of engaging member from output gear even when the vehicle is on inclined road condition.
[00056] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. For example, the rotational movement can be arrested by using a dedicated stopper configured in a housing. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

List of References:

C-C' Lateral direction
V Volume
R Right
L Left side
P Pivoted connection
101 Powertrain
102 Prime mover
103 Side cover; 103R, 103L -Right side cover, Left side cover
104 Side wall
105 Outer surface of left side cover
106 Interior surface of side wall
107 End surface of sidewall
108 Parking pawl assembly
109 Cover member
110 Internally threaded aperture
111 Attachment means
201 Multispeed assembly
202 Gear shift and select assembly
203 Actuator
204 Decoupling device
205 Reduction device
206 Gear shift shaft
207 Gear shift fork
208 Output shaft
209 Worm gear profile
210 Rack profile
211 High torque gearing
211I High torque input gearing
211ID Drive gear
211O High torque output gearing
211OD Driven gear
212 Low torque gearing
212I Low torque input gearing
212ID Drive gear
212O Low torque output gearing
212OD Driven gear
213 Input shaft assembly
214 Involute splines
215 Counter shaft assembly
216 Engaging member
216P Primary end of the engaging member
216S Secondary end of the engaging member
216C Counterweight
217 Output gear
218 Cushion member
301 Input shaft
301T Threaded portion
302 Attachment means
303 Counter shaft
304 Circlip
305 Opening
306 Resilient member
307 Bush member
308 Cam lock
308F First leg of cam lock
308S Second leg of cam lock
309 Opening in parking pawl
310 Groove in counter shaft
311 Groove in bush member
401 Stopper
402 Hand lever