A CLUTCH DISENGAGÉMENT MECHANISM

FIELD OF THE INVENTION

[0001] The present invention relates generally to a clutch disengagement mechanism, and more particularly, but not exclusively, to a clutch disengagement mechanism for a vehicle provided with an engine having automatic transmission.

BACKGROUND OF THE INVENTION

[0002] Straddle type vehicles such as motorcycles generally have a manual transmission system to carry the pówer generated by an internal combustión (IC) engine, in a controllable way, to a wheel of the vehicle. The manual transmission system comprises a system of interlocking gears such that by operating a gear shift lever manually, the driver can choose one of the several ratios of speed between the input shaft and the output shaft. To allow smooth and gradual shifting of gears, a clutch is provided to isolate the engine from the transmission momentarily. When the driver releases the clutch lever manually, the discs in the clutch assembly aré squeezed with eacrT other and thus the transmission is engaged with the engine.

[0003] Off lately, automated manual transmission (AMT) systems have come into use for ease of operation of clutch actuation and gearshift. The ride on such vehicle is less tiring for the vehicle rider. Conventionally, a vehicle fitted with an AMT engine has electrically controlled clutch operation and gearshift operation powered by a battery and controlled by a micro controller. Düe to this, the engine is not equipped to tackle any electrical failure issues. For example, it is probable that in the event of malfunction of the controller or during any other electrical fault, the vehicle would be stuck in the clutch engaged position. On occurrence of mis event, the vehicle wóuld come to a stop and it would not be possible for the driver, due to clutch engagement, to push the vehicle to the nearby service centre for vehicle check-up or mainténance to bring it into operable condition again. In another condition, the battery may be discharged completely thereby halting the electrical operations.

SUMMARY OF THE INVENTION

[0004] It is therefore fruitful to also have a manual control over the AMT engine to ride through any unexpected electrical failuré events. The present invention tries to solve one or more problems and obviate a lacunae in the known art. It is an object of the present invention to provide an IC engine háving an automatic and manually controllable clutch actuation without major design changes in the engine layout. It is an object of the present invention to provide a simple and unsophisticated mechanism by which the automatic clutch of the vehicle can be disengaged manually from the engine.

[0005] The present invention therefore discloses an internal combustion engine comprising an electrically operated clutch, a clutch cover covering said clutch and a clutch disengagement mechanism for disengaging said electrically operated clutch in the event of an electric failure. The clutch disengagement mechanism further comprises an actuator plunger having an engaging portion and a manually operated clutch reléase lever operatively connected with a clutch reléase shaft having an end portion configured to engage with the engaging portion of the actuator plunger. On manual operation of the clutch reléase lever, the end portion of the clutch reléase shaft operates the engaging portion of the actuator plunger which further acts ori the clutch reléase pin and disengages said clutch from the engirie.

[0006] Thus, the present invention discloses for an automatic (or electrically operated) clutch, a lirftp home mode in the form of a clutch disengagement mechanism which can be operated manually for operating the automatic clutch during any undesirable event (including during the failure of automatic transmission system) so as to facilitate the rider to push the vehicle to the nearby service centre.

[0007] According to a feature óf the present invention, the clutch disengagement mechanism further comprises of a guide-cum-holder member which partially covers and supports said end portion and said engaging portion and keeps them guided towards their intended path.

[0008] The foregoing objectives and summary is provided to introduce a selection of concepts in a simplified form, and is not limiting. To fully appreciate these and other objects of the present subject matter as well as the subject matter itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the subject matter and the claims should beread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0009] The above and other features, aspects and advantages of the subject matter will be better understood with regard to the following description, appended claims and accompanying drawings where:

[00010] FIG. 1 shows a side view. of an IC engine with an automatic clutch and a clutch disengagement mechanism according to the present invention.

[00011] FÍG. 2 shows an exploded view of an embodiment of the clutch disengagement mechanism disposed internal to a clutch cover according to the present invention.

[00012] FIG. 3 shows an inner view of the clutch disengagementmechanism of FIG. 2 supported on the clutch cover.

[00013] FIG. 4 shows a sectional view of the clutch disengagement mechanism.

[00014] FIG. 5 shows the exploded view of assembly of clutch disengagement mechanism in the clutch cover.

[00015] FIG. 6 shows a perspéctive view of a guide-cüm-holder member according to an embodiment pf the present invention.

[00016] - FIG. 7 shows an illustrative. rear perspéctive view of the concept of the clutch disengagement mechanism engaged with a clutch.

[00017] FIG. 8 shows a illustrative front perspéctive view. of the concept of the clutch disengagement mechanism along with the guide-cum-holder member.

DETAILED DESCRIPTION OF THE INVENTION

[00018] The present invention disclosed herein is usable with an engine with an automatic, electrically operated clutch. It is to be noted that "front" and "rear", unless mentioned otherwise, refer to front and rear directions as seen in a state of being seated on a seat of the vehicle carrying the present invention and looking forward. Such vehicle is installed with the engine with. its cylinder head facing towards the front. Further, "left" and "right", unless mentioned otherwise, refer to left and right directions of an onlooker standing in front of the vehicle and looking towards it. A lateral axis refers generally to a side to side, or left to right axis relative to the vehicle. Various other features of the present subject matter here will be discernible from the following further description thereof, set out hereunder.

[00019] FIG. 1 and FIG. 2 respectively show a side view and exploded view of an IC engine 100 having a cylinder head 101 and a transmission system disposed internal to a clutch cover 102. The transmission system has an automatic clutch 139 connected to the engine and covered by the clutch cover 102. The clutch cover 102 has an inner surface 104 facing towards the clutch 139 and an outer surface 103 opposed to the inner surface 104. The clutch actuation system for automatically actuating the operation of clutch engagement and disengagement includes a clutch actuation motor 105, a reduction gear box comprising of a plurality of reduction gears attached to the clutch actuation motor 105, a pówer transmission mechanism which transmits the rotational driving forcé of the clutch actuation motor 105, a clutch position sensor 111 which detects the actüation of the clutch, a thrust bearing 106, a ball bearing 107 and a washer. The clutch actuation motor 105 is mounted and secured to an outer surface of the clutch cover 102 and sealed against ingress of oil. The clutch actuation motor 105 is eíectrically connected to a controller (not shown) which may be programmed to control the direction of rotation of the clutch actuation motor 105 as well as the time duration of its operation.

[00020] As. shown in FIG. 2, the automatic clutch 139 is eíectrically operated through the clutch actuation motor 105 via the power transmission mechanism which comprises of a worm gear 108 operatively meshed with a worm wheel 110. The worm wheel 110 in turn is connected to an actuator plunger 115. In a preferred embodiment, the actuator plunger i 15 is a circular píate structure engaged on its one side with the worm wheel 110 through a ramped ball mechanism, and on its other' side with a clutch reléase pin 137. A plurality of ramped balls 114 are caged in a ball carrying member 113 disposed between the actuator plunger 115 and worm wheel 110. In this way, the actuator plunger 115 takes rotational driving forcé from the worm wheel 110 through the ramped ball mechanism and operates a clutch reléase pin 137 thereby engaging and disengaging the clutch 139 without any manual intervention. The clutch 139 works with the help of a clutch píate assembly 138 through which it is engaged to and disengaged from a primary driven gear 140 takirig its drive from a crankshaft of the engine.

[00021] When the eíectrically operated clutch actuation system for clutch disengagement fails due to any reason and the vehicle is stuck on road, the clutch disengagement mechanism described hérein helps the rider to manually disengage the automatic clutch. FIG. 3 shows an inner view of the clutch disengagement mechanism supported on the clutch cover 102 which has an outer surface 103 and an inner surface 104. The clutch disengagement mechanism comprises the actuator plunger 115 operating the clutch reléase pin 137 and having an engaging portion 116; and a manually operated clutch reléase lever 121 operatively connected with a clutch reléase shaft 125, the clutch reléase shaft 125 having an end portion 126 configured to engage with the engaging portion 116 of the actuator plunger 115. The engaging portion 116 of the actuator plunger 115 is extended centrally from one side of the actuator plunger 115 engaged with the clutch reléase pin. The engaging portion 116 engages with the end portion 126 of the clutch reléase shaft 125. It also operates the clutch reléase pin 137 when the need to manually disengage the clutch arises.

[00022] According to an aspect of the present invention, the actuator plunger 115 and the clutch reléase shaft 125 are operatively engaged through a rack and pinion arrangement as shown in FIG. 4. In an embodiment, the engaging portion 116 of the actuator plunger 115 comprises a rack 117, the end portion 126 of the clutch reléase shaft 125 comprises a pinion 127 having a plurality of grooves that intermesh with the grooves of the rack. In an embodiment, the clutch reléase lever 121 is rotatably connected to the clutch reléase shaft 125. During the operation of the clutch disengagement mechanism, the rotatory motion of the clutch reléase shaft 125 is converted to the axial motion of the actuator plunger 115.

[00023] According to another aspect of the present invention, the clutch reléase shaft 125. is received in a supporting boss 129a formed integral with the clutch cover 102 as shown in FIG. 5. A corresponding supporting bush 123a súpports the clutch reléase shaft in the said supporting boss 129a. In a prefeíred embodiment, a plurality of supporting bosses 129a, 129b support the clutch reléase shaft 125 with the help of a plurality of corresponding supporting bushes 123a, 123b. The supporting bushes avoid wear and tear of the clutch reléase shaft 125.

[00024] A sealing member 122 provided around a portion of the clutch reléase shaft 125 prevenís the oil leak from thé clutch cover 102. The sealing member 122 may be a circular ring disposed adjacent to the supporting boss 129a closest to the clutch reléase lever 121. The clutch reléase shaft 125 further comprises of a preloaded return spring 124 to bring the clutch reléase shaft 125 to its original position after the withdrawal of manual forcé on the clutch reléase lever 121. One end of the return spring is held on the inner surface 104 of the clutch cover 102.

[00025] The clutch reléase lever 121 is manually operable and is provided external to the clutch cover 102 for ease of access to the rider of the vehicle. The clutch reléase lever 121 is rotatably connected to the clutch reléase shaft 125. However, the extent of rotation of the clutch reléase lever 121 is predetermined. It rotates only to that extent as the axial movement required by the engaging portion 116 of the actuator plungerto opérate the clutch reléase pin 137. In another embodiment, the clutch reléase lever 121 may be operated by the rider of the vehicle through a cable connected to another-lever placed in cióse proximity of the handle bar of the vehicle.

[00026] The working of the clutch disengagement mechanism is now explained with the help.of FIG.7 and FIG. 8. When the rider of the vehicle detects that the automatic clutch actuation system has failed due to ariy reason whatsoever (ineluding electrical failures) and the vehicle comes to a stop with clutch in engaged position with the engine, he may use the present clutch disengagement mechanism to disconnect the drive to the wheel. The rider can manually turn the clutch reléase lever 121 as shown by the arrow. On manual operation of the clutch reléase lever 121, the end portion 126 of the clutch reléase shaft 125 operates the engáging portion 116 of the actuator plunger 115. The rotatory motion of the clutch reléase shaft 125 is converted to the axial motion of engáging portion 116 of the actuator plunger 115. Subsequently, one end óf the engáging portion 116 operates the clutch pin 137 due to which the clutch plates 138 slip and the clutch 139 is disengaged. The preloaded return spring 124 brings the clutch reléase shaft 125 toits original position after the withdrawal of manual forcé on the clutch reléase lever 121.

[00027] For effective working of the clutch disengagement mechanism, it is essential that end portion 126 of the clutch reléase shaft 115 and engáging portion 116 of the actuator plunger 115 remain in contact with each other for transfer of input from the clutch reléase lever 121. However, it is possible that the end portion 126 of the clutch reléase shaft and the engáging portion 116 of the actuator plunger do not move in the intended direction completely and deviate from their intended path due to lack of any guiding support. The mechanism can also be disturbed by engine vibrations. Therefore, the clutch disengagement mechanism further comprises of a guide-cum-holder member is provided which partially covers and supports the end portion 126 and the engaging portion 116, and keeps them guided towards their intended path.

[00028] FIG. 6 shows a perspective view of the guide-cum-holder member 130. According to an embodiment of the present invention, the guide-cum-holder member 130 is a wheel like structure having a plurality of spokes 136. Each spoke 136 has a mounting recess 133 through which the guide-cum-holder member 130 is supported on the inner surface 104 of the clutch cover 102v The spokes 136 converge to define a first central groove 134 to partly receive the engaging portion 116 of the actuator plunger 115. The first central groove 134 is a through groove disposed at the centre of the guide-cum-holder member 130 through which it is supported on the actuator plunger 115. A second groove 135 is a longer groove provided adjacent to the first central groove 134 to receive the end portion 126 of the clutch reléase shaft 125. It spans both sides of the first central groove 134. According to an aspect, the axis of the first central groove 134 and the axis of the second groove 135 are perpendicular to each other. It is to be noted that the first central groove 134 only minimally supports the engaging portion 116 of the actuator plunger 115 so that it moves axially along the clutch pin axis. Meanwhile, the second groove 135 substantially supports the end portion 126 of the clutch reléase shaft 125. The said grooves do not interfere in the engagement of the end portion 126 and the engaging portion 116.

[00029] The guide-cum-holder member 130 maintains the central distance between the rack and pinion arrangement of the clutch reléase shaft and the actuator plunger. It protects the mechanism from misalignment between the rack and pinion arrangement. It guides the plunger to move axially and alsó pro vides rigidity to the system.

[00030] According to another aspect, the guide-cum-holder member 130 is supported on the inner surface 104 of the clutch cover 102 through a plurality of mounting bolts 131 passing through corresponding cylindrical members 132 and securing the guide-cum-holder member 130 to the clutch cover 102. The mounting bolts 131 pass through the mounting reeess 133 and secure the guide-cum-holder member 130 to a plurality of mounting bosses 142 provided on the inner surface 104 of the clutch cover 102. The cylindrical members 132 may be 'dowels' which maintain the position of the guide-cum-holder member 130 with the clutch cover 102. The actuator plunger 115, the clutch reléase shaft 125, the guide-cum-holder member 130 are housed internal to the clutch cover 102.

[00031] Itvwill be appreciated that the present invention and its equivalent thereof offers mahy advantages, including those which have been described forthwith. The present invention provides a fail-safe mechanism to a vehicle having an automatic clutch actuation mechanism. It combines the functionality of an automatic clutch actuation mechanism along with the safety of a manual clutch. disengagement mechanism and helps a rider to push the vehicle to a service centre in the event of automatic clutch actuation system failure. It is extremely simple in construction and function and does not require any complex structures.

[00032] The present subject matter is thus described. The description is not intended to be exhaustive ñor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiments máy be modified in light of the above description. The embodiments described are chosen to proyide an illustration of principies of the invention and its practical application to enable thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modificatipns as are suited to the particular use contemplated. Therefore the forgoing description is -to be considered exemplary, rather than limiting, and the true scope of the invention is that described in the appended claims.

We claim:

1. An intemal combustión engine (100) comprising an electrically operated clutch (139), a clutch cover (102) covering said clutch (139) and a clutch disengagement mechanism for disengaging said electrically operated clutch in the event of an electric failure, the clutch disengagement mechanism further comprising:
an actuator plunger (115) adapted to opérate a clutch reléase pin (137) and having an engaging portion (116);
a manually operated clutch reléase lever (121) operatively connected with a clutch reléase shaft (125), the clutch reléase shaft (125) having an end portion (126) configured to engage with the engaging portion (116) of the actuator plunger (115);
wherein on manual operation of the clutch reléase lever (121), the end portion (126) of the clutch reléase shaft (125) operates the engaging portion (116) of the actuator plunger (115) which further acts on the clutch reléase pin (137) and disengages said clutch (139) from the engine.

2. The intemal combustión engine as claimed in claim 1, wherein the clutch disengagement mechanism includes a guide-cum-holder member (130) adápted to support the engaging portion (116) of the actuator plunger (115) and the end portion (126) of the clutch reléase shaft (125).

3. The intemal combustión engine as claimed in claim 2, wherein the guide-cum-holder member (130) comprises a first central groove (134) to receive the engaging portion (116) of the actuator plunger (115) and a second groove (135) adjacent to the fifst central groove (134) to receive the end portion (126) of the clutch reléase shaft (125).

4. The intemal combustión engine as claimed in claim 3, wherein the axis of the first central groove (134) and the axis of the second groove (135) are perpendicular to each other.

5. The intemal combustión engine as claimed in claim 1, wherein the actuator plunger (115) and the clutch reléase shaft (125) are operatively engaged through a rack and pinion arrangement.

6. The intemal combustión engine as claimed in claim 5, wherein the engaging portion (116) of the actuator plunger (115) includes a rack (117) having a first set of grooves, the end portion (126) of the clutch reléase shaft (125) comprises a pinion (127) having a second set of grooves; the second set of grooves intermeshing with the first set of grooves of the rack.

7. The intemal combustión engine as claimed in claim 1, wherein the clutch reléase shaft (125) further comprises of a preloaded retum spring (124) to bring the clutch reléase shaft (125) to its original position after the withdrawal of manual forcé on the clutch reléase lever (121).

8. The internal combustión engine as claimed in claim 1 or claim 2, wherein the actuator plunger (115), the clutch reléase shaft (125) and the guide-cum-holder member (130) are housed internal to the clutch cover. (102).

9. The internal combustión engine as claimed in claim 1, wherein the clutch reléase shaft (125) is received in one or more supporting bosses (129a, 129b) formed in the clutch cover (102) and the clutch reléase lever (121) is provided external to the clutch cover (102).

10. The clutch disengagement mechanism as claimed in claim 8, wherein the guide-cum-holder member (130) is mounted on an inner surface (104) of the clutch cover (102) through a plurality of mounting bolts (131) passing through corresponding cylindrical members (132) formed in the clutch cover (102) and securing the guide-cum-holder member (130) to the clutch cover (102).