DESC:MODULAR TRANSMISSION ARRANGEMENT FOR SEQUENTIAL AND H-GATE SHIFT SYSTEMS IN INTEGRAL TRANSMISSION

Field of the invention:

The present invention relates to manual transmission in an internal combustion engine, and more particularly provides a transmission layout having modular design adapted to work with a sequential and an H-gate shift system.

Background of the invention:

An H-pattern manual transmission uses an H type movement of the gear selection lever while a sequential transmission works with upward and downward movement of the lever, to shift between the gears.

In sequential gear box the speed (gear selection) are to be selected in order, and direct access to specific speed (gear selection) is not possible as contrast to that in the H-pattern manual transmission. In case of the H-type gear boxes, gear selection can be done randomly whereas in the sequential gear boxes, the gear selection needs to be done in sequential manner.

Currently, the existing systems require different layouts for both- the H-type and the sequential shift systems. A true sequential transmission will very often use a dog clutch engagement rather than the more usual synchromesh as fitted to a normal H-pattern road vehicle gearbox. To use H-gate shift system, the synchromesh is mandatory. Further, the sequential transmissions don’t allow the driver to select randomly any gear. As an alternative, the driver may only walk through all the gears next-lower or next-higher gear speed. Since, the sequential transmissions require the operation of an extra gear selection travel, and keeping the vehicle in the correct gear at all times, as a result of which they require a bit more concentration, especially in heavy traffic situations.
Therefore, there exists a need to provide a modular transmission arrangement for mounting the H-gate shift system within the same transmission layout of the sequential shift system thereby eliminating the need for the synchromesh. There exists a need to address the aforementioned drawbacks of existing systems by providing a modular transmission arrangement that is cost effective, and having similar construction for assembling both- the sequential and the H gate shift systems thereby providing ease of use and ease of serviceability.

Objects of the invention:

The primary object of present invention is to provide a common transmission layout for assembling H-gate shift system and sequential shift system.

Another object of the present invention is to eliminate the need of using separate synchromesh system for H-gate shift gearbox.

Yet, another object of the present invention is to operate vehicle using the H-gate shift gearbox by dog tooth gears of the sequential shift system without using synchronizers.

Summary of the invention:

The present invention provides a modular transmission arrangement for gear shift system in an integral combustion engine. The modular transmission arrangement comprises of a set of dog tooth gears adapted for assembling and operating the gear shift systems and a shift lever connected with the gear shift system. The gear shift system is selected from any one of H-gate shift system and sequential gear shift system. The dog tooth gears are designed for the gear ratio and are adapted for performing dual duty of power transmission and sliding engagement thereby eliminating need for a separate synchronizer for operating the H-gate shift system.

The H-gate shift system includes at least three H-gate shaft forks, a H-gate common rail assembly, a H-gate shift finger, a synchro sleeve and a H-gate common detent. The at least three H-gate shaft forks includes a H-gate first fork for selecting any one of the first gear and the second gear, a H-gate second fork for selecting any one of the third gear and the fourth gear and a H-gate third fork for selecting any one of the fifth gear and the reverse gear, wherein at least one fork spring is provided in each fork to ensure fork and gear in neutral position and while engaging the one gear other fork and gear to be in neutral condition in a gear box. The H-gate common rail assembly is operably connected with the at least three H-gate shaft forks and adapted for operating in rotary motion and linear motion with an external cable mechanism. The H-gate shift finger is assembled with the H-gate common rail assembly using a pin. The H-gate common detent is assembled on the H-gate common rail assembly to give shift force to the H-gate shift system while engaging and disengaging the gear. The shift lever is operably connected with the H-gate common rail assembly, the at least three shift forks and the synchro sleeve. The H-gate first fork actuates the first gear in response to travelling of the H-gate shift finger to left side and actuates the second gear in response to travelling of the H-gate shift finger to right side. The H-gate second fork actuates the third gear in response to travelling of the H-gate shift finger to the left side and actuates the fourth gear when the H-gate shift finger travels to the right side. The H-gate third fork actuates the fifth gear in response to traveling of the H-gate shift finger to the left side and actuates the reverse gear when the H-gate shift finger travels to the right side. The H-gate common detent of the shift system is pressed within housing with a calculated height of around 17.0 mm with respect to a housing machining face and calculated preload is around 90N at the H-gate common rail assembly for adding the main shift. The pre load force of the fork spring is around 20 N and the stiffness is around 6 N/mm for the H-gate shift system.

The sequential shift system includes at least three sequential shaft forks, a sequential common rail assembly, a sequential shift drum, a sequential common rail gear and a ratchet mechanism. The at least three sequential shaft forks includes a sequential first fork for selecting any one of the first gear and the second gear, a sequential second fork for selecting any one of the third gear and the fourth gear and a sequential third fork for selecting fifth reverse gear. The sequential common rail assembly is operably connected with the at least three sequential shaft forks. The sequential shift drum is pinned with the sequential common rail assembly. The sequential shift drum has three profiles configured around a circumference thereof for assembling three sequential shaft forks thereon. The sequential common rail gear is assembled with the sequential common rail assembly , wherein the sequential common rail gear is adapted for operating in rotary motion including a clock wise motion for engaging the dog tooth gears from R-N-N-1-2-3-4-5 and an anti-clock wise motion for disengaging the dog tooth gears from 5-4-3-2-1-N-N-R. The ratchet mechanism is connected to the shift lever at one end and connected to the sequential shift drum at other end, wherein the ratchet mechanism converts fore and aft motion of the shift lever into a rotary motion, thereby turning the sequential shift drum for actuating any one of the at least three sequential shaft forks. The sequential common detent is provided with pre load of 90N and actuating on ram profile that is integral on the sequential shift drum to engage the gear and to control rotation of the sequential shift drum as required rotation. The sequential common rail gear is connected to a matting gear that is connected to a shift cable and the shift cable is further connected to shift lever to allow changing gears as per the requirement. The sequential first fork actuates the first gear when the sequential shift drum rotates in the clock wise direction and actuates the second gear when the sequential shift drum rotates further to the clock wise direction. The sequential second fork actuates the third gear when the sequential shift drum rotates in the clock wise direction and actuates the fourth gear when the sequential shift drum rotates further to the clock wise direction. The sequential third fork actuates the fifth gear when the sequential drum rotates clock wise further and actuates the reverse gear when the sequential drum comes back to a neutral position and rotates in anti-clock wise direction.
Brief description of the drawings:

The objectives and advantages of the present invention will be more clearly understood from the following description of the invention taken in conjunction with the accompanying drawings, wherein;

Figure 1 shows a transaxle with H- gate shift mechanism, in accordance with present invention;

Figure 2 shows an H- gate shifting pattern;

Figure 3 shows a transaxle with sequential shift mechanism, in accordance with present invention;

Figure 4 shows a sequential shifting pattern.

Detailed description of the invention:

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with the prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a modular transmission arrangement for sequential shift and H-gate shift systems in integral transmission. The modular transmission arrangement can be assembled either with the H-shift system or with the sequential shift system within the same layout thereby eliminating the need of using a separate synchromesh system for operation of the H-shift system. The H-shift system assembled within the modular transmission arrangement is capable of operating using dog teeth gear that is provided for operation of the sequential shift system.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Manual transmission system in automobiles includes a sequential shift system (80) and a H-gate shift system (40). The sequential shift system (80) also referred as “the drum-type shift system”, often incorporate a synchro-less dog-clutch engagement mechanism instead of synchromesh dog clutch common on H-pattern automotive transmission, thereby requiring different layout for each of the shift system.

Referring to figures 1- 4, there is shown a modular transmission arrangement (100) for assembling the H-gate shift system (40) and the sequential shift system (80). The modular transmission arrangement (100) is adapted for assembling both the shift systems (40, 80) thereby eliminating a need for separate synchromesh assembly for operating the H-gate shift system (40). The modular transmission arrangement (100) makes use of only dog tooth gears (not numbered) for operating both- the sequential shift system (80) and the H-gate shift system (40). Particularly, the dog tooth gears are designed for the gear ratio and are adapted for performing dual duty of power transmission and sliding engagement thereby eliminating the need for a separate synchronizer for operating the H-gate shift system (40). In an embodiment, the dog tooth gears are adapted to be operable for performing dual mode shift system. Still further, use of merely dog tooth gears for performing dual mode shifting including the H- gate shifting (40) and the sequential shifting (80) offers an advantage of space since the dog tooth gears are typically smaller in diameter. Also, the dog tooth gears controls selection of gear speed, so absolute speeds of the engaging parts is lower, aiding engagement. The set of dog tooth gears comprises of at least five gears including first gear, second gear, third gear, fourth gear, fifth gear and reverse gear. A shift lever (not numbered) is operably connected with the any one of the gear shift systems (40, 80).

Now, referring to figure 1 and 2, in accordance with the present invention, in a gear box of the H-gate shift system (40) includes at least three H-gate shaft forks (1, 2 ,3), a H-gate common rail assembly (4), a H-gate shift finger (5), a synchro sleeve (not numbered) and a H-gate common detent (not numbered).

The at least three H-gate shaft forks includes a H-gate first fork (1) for selecting any one of the first gear and the second gear, a H-gate second fork (2) for selecting any one of the third gear and the fourth gear and a H-gate third fork (3) for selecting any one of the fifth gear and the reverse gear, wherein at least one fork spring (not shown) is provided in each fork to ensure fork and gear in neutral position and while engaging the one gear other fork and gear to be in neutral condition in the gear box.

The H-gate common rail assembly (4) is operably connected with the at least three H-gate shaft forks (1, 2, 3) and adapted for operating in rotary motion and linear motion with an external cable mechanism (not shown). In an embodiment, rotation movement of the H-gate common rail assembly (4) offers selection of gear plane whereas the linear motion of the H-gate common rail assembly (4) offers shifting of the gear. The H-gate shift finger (5) is assembled with the H-gate common rail assembly (4) using a pin (not shown).

The shift lever is operably connected with the H-gate common rail assembly (4), the at least three shift forks (1, 2, 3) and the synchro sleeve.

The H-gate first fork (1) actuates the first gear in response to travelling of the H-gate shift finger (5) to left side and actuates the second gear in response to travelling of the H-gate shift finger (5) to right side. The H-gate second fork (2) actuates the third gear in response to travelling of the H-gate shift finger (5) to the left side and actuates the fourth gear when the H-gate shift finger (5) travels to the right side. The H-gate third fork (3) actuates the fifth gear in response to traveling of the H-gate shift finger (5) to the left side and actuates the reverse gear when the H-gate shift finger (5) travels to the right side.

The H-gate common detent (not numbered) is assembled on the H-gate common rail assembly (4) to give shift force to the H-gate shift system (40) while engaging and disengaging the gear. In an embodiment, the H-gate common detent is pressed within the housing with a calculated height. In an alternate embodiment, the H-gate common detent is pressed to a height of 17.0 mm with respect to the housing machining face. In another embodiment, the preload calculated is around 90N at the H-gate common rail assembly (4) for adding the main shift force.

Now, referring to figure 3 and 4, in accordance with the present invention, in the gear box of the sequential shift system (80) includes at least three sequential shaft forks (6, 7, 8), a sequential common rail assembly (9), a sequential shift drum (10), a sequential common rail gear (11) and a ratchet mechanism.

The at least three sequential shaft forks includes a sequential first fork (6) for selecting any one of the first gear and the second gear, a sequential second fork (7) for selecting any one of the third gear and the fourth gear and a sequential third fork (8) for selecting fifth reverse gear.
The sequential common rail assembly (9) is operably connected with the at least three sequential shaft forks (6, 7, 8). The sequential shift drum (10) is pinned with the sequential common rail assembly (9). The sequential shift drum (10) has three profiles (not numbered) configured around a circumference thereof for assembling three sequential shaft forks (6, 7, 8) thereon.

The sequential common rail gear (11) is assembled with the sequential common rail assembly (10). The sequential common rail gear (11) is adapted for operating in rotary motion including a clock wise motion for engaging the dog tooth gears from R-N-N-1-2-3-4-5 and an anti-clock wise motion for disengaging the dog tooth gears from 5-4-3-2-1-N-N-R.

The ratchet mechanism is connected to the shift lever at one end and connected to the sequential shift drum at other end. The ratchet mechanism converts fore and aft motion of the shift lever into a rotary motion, thereby turning the sequential shift drum (10) for actuating any one of the at least three sequential shaft forks (6, 7, 8).

The sequential first fork (6) actuates the first gear when the sequential shift drum (10) rotates in the clock wise direction and actuates the second gear when the sequential shift drum (10) rotates further to the clock wise direction. The sequential second fork (7) actuates the third gear when the sequential shift drum (10) rotates in the clock wise direction and actuates the fourth gear when the sequential shift drum (10) rotates further to the clock wise direction. The sequential third fork (8) actuates the fifth gear when the sequential drum rotates (10) clock wise further and actuates the reverse gear when the sequential drum (10) comes back to a neutral position and rotates in anti-clock wise direction.

Further, the sequential common detent is provided with pre load of 90N and actuating on ram profile that is integral on the sequential shift drum (10) to engage the gear and to control rotation of the sequential shift drum (10) as required rotation.

The sequential common rail gear (11) is connected to a matting gear (not numbered) that is connected to a shift cable (not shown). The shift cable is further connected to shift lever to allow changing gears as per the requirement.

Thus, the present invention provides the modular transmission arrangement (100) for assembling the H-gate shift system (40) and the sequential shift system (80) thereon using a common layout. The modular transmission arrangement (100) uses only dog tooth gear for operation thereby eliminating the need for using the synchronizer system. Particularly, the dog tooth gears are designed for the gear ratio and to do dual duty of power transmission and sliding engagement.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the scope of the invention.
,CLAIMS:We Claim:

1. A modular transmission arrangement (100) for gear shift system in an integral combustion engine comprises of:
a set of dog tooth gears adapted for assembling and operating the gear shift systems, wherein the gear shift system is selected from any one of H-gate shift system (40) and sequential gear shift system (80), wherein the set of dog tooth gears comprises of at least five gears including first gear, second gear, third gear, fourth gear, fifth gear and reverse gear; and
a shift lever operably connected with the gear shift system;
characterized in that, the modular transmission arrangement (100) comprising:
the H-gate shift system (40) having,
• at least three H-gate shaft forks including a H-gate first fork (1) for selecting any one of the first gear and the second gear, a H-gate second fork (2) for selecting any one of the third gear and the fourth gear and a H-gate third fork (3) for selecting any one of the fifth gear and the reverse gear, wherein at least one fork spring is provided in each fork (1, 2, 3) to ensure fork and gear in neutral position and while engaging the one gear other fork and gear to be in neutral condition in a gear box,
• a H-gate common rail assembly (4) operably connected with the at least three H-gate shaft forks (1, 2 ,3) and adapted for operating in rotary motion and linear motion with an external cable mechanism,
• an H-gate shift finger (5) assembled with the H-gate common rail assembly (4) using a pin, and
• a synchro sleeve,
• a H-gate common detent assembled on the H-gate common rail assembly (4) to give shift force to the H-gate shift system while engaging and disengaging the gear,
wherein, the shift lever is operably connected with the H-gate common rail assembly (4), at least three shift forks (1, 2, 3) and the synchro sleeve, and
the sequential shift system (80) having,
• at least three sequential shaft forks including a sequential first fork (6) for selecting any one of the first gear and the second gear, a sequential second fork (7) for selecting any one of the third gear and the fourth gear and a sequential third fork (8) for selecting fifth reverse gear,
• a sequential common rail assembly (9) operably connected with the at least three sequential shaft forks (6, 7, 8)
• a sequential shift drum (10) pinned with the sequential common rail assembly (9), wherein the sequential shift drum (10) has three profiles configured around a circumference thereof for assembling three sequential shaft forks (6, 7, 8) thereon,
• a sequential common rail gear (11) assembled with the sequential common rail assembly (9), wherein the sequential common rail gear (11) adapted for operating in rotary motion including a clock wise motion for engaging the dog tooth gears from R-N-N-1-2-3-4-5 and an anti-clock wise motion for disengaging the dog tooth gears from 5-4-3-2-1-N-N-R,
• a ratchet mechanism connected to the shift lever at one end and connected to the sequential shift drum (10) at other end, wherein the ratchet mechanism converts fore and aft motion of the shift lever into a rotary motion, thereby turning the sequential shift drum (10) for actuating any one of the at least three sequential shaft forks (6, 7, 8) and
• a sequential common detent provided having pre load of 90N and actuating on ram profile that is integral on the sequential shift drum (10) to engage the gear and to control rotation of the sequential shift drum (10) as required,
wherein, the sequential common rail gear (11) is connected to a matting gear that is connected to a shift cable and the shift cable is further connected to shift lever to allow changing gears as per the requirement;
2. The modular transmission arrangement (100) as claimed in claim 1, wherein the H-gate first fork (1) actuates the first gear in response to travelling of the H-gate shift finger (5) to left side and actuates the second gear in response to travelling of the H-gate shift finger (5) to right side.

3. The modular transmission arrangement (100) as claimed in claim 1, wherein the H-gate second fork (2) actuates the third gear in response to travelling of the H-gate shift finger (5) to the left side and actuates the fourth gear when the H-gate shift finger (5) travels to the right side.

4. The modular transmission arrangement (100) as claimed in claim 1, wherein the H-gate third fork (3) actuates the fifth gear in response to traveling of the H-gate shift finger (5) to the left side and actuates the reverse gear when the H-gate shift finger (5) travels to the right side.

5. The modular transmission arrangement (100) as claimed in claim 1, wherein the H-gate common detent of is pressed within housing with a calculated height of around 17.0 mm with respect to a housing machining face and calculated preload is around 90N at the H-gate common rail assembly (4) for adding the main shift force.

6. The modular transmission arrangement (100) as claimed in claim 1, wherein the pre load force of the fork spring is around 20 N and the stiffness is around 6 N/mm for the H-gate shift system.

7. The modular transmission arrangement (100) as claimed in claim 1, wherein the sequential first fork (6) actuates the first gear when the sequential shift drum (10) rotates in the clock wise direction and actuates the second gear when the sequential shift drum (10) rotates further to the clock wise direction.

8. The modular transmission arrangement (100) as claimed in claim 1, wherein the sequential second fork (7) actuates the third gear when the sequential shift drum (10) rotates in the clock wise direction and actuates the fourth gear when the sequential shift drum (10) rotates further to the clock wise direction.

9. The modular transmission arrangement (100) as claimed in claim 1, wherein the wherein the sequential third fork (8) actuates the fifth gear when the sequential drum (10) rotates clock wise further and actuates the reverse gear when the sequential drum (10) comes back to a neutral position and rotates in anti-clock wise direction.

10. The modular transmission arrangement (100) as claimed in claim 1, wherein the dog tooth gears are designed for the gear ratio and are adapted for performing dual duty of power transmission and sliding engagement thereby eliminating need for a separate synchronizer for operating the H-gate shift system (40).

Dated this 01st day of March 2018

Madhavi Vajirakar
(Agent for Applicant)
IN/PA-2337