Description:FIELD OF INVENTION

The present invention relates to a mechanism for reducing clutch-pedal vibrations in automobiles. In particular, the present invention relates to a spring mechanism for damping vibrations felt in the clutch-cover assembly. More particularly, the present invention relates to a compact spring mechanism for enhancing the driver’s comfort by filtering and dampening the vibrations felt at the clutch-pedal.

BACKGROUND OF THE INVENTION

In manual transmission vehicles, smooth clutch operation is of significant requirement for a comfortable driving experience. However, there are vibrations emanate from the internal combustion engine (ICE) and which are generally caused due to an unbalanced crankshaft and ICE firing impulses. In high powered light weight engine vehicles, engine vibrations are felt on the clutch pedal by the driver leading to discomfort.

An article titled: “Clutch pedal vibration – Investigation and counter measures” by Andreas Anstätt, Carsten Mohr, and Dirk Klünder [LuK GmbH & Co. oHG, Germany], discusses the issues with clutch pedal vibration (Figures 1a-1b).

Due to the engine firing impulses, crankshaft tends to bend resulting in flywheel swashing movement causing axial vibration thereof and the vibration of clutch release bearing via the clutch cover diaphragm spring. Since by depressing the clutch-pedal, a plunger is pushed into the master cylinder bore and the valve disposed at the end of this bore closes the outlet to the hydraulic fluid tank, the aforesaid plunger movement pushes the hydraulic fluid from said fluid tank to the slave cylinder and the piston thereof moves the clutch release bearing for disengaging the clutch. On releasing the clutch-pedal, the slave cylinder piston is reversed due to the cover diaphragm spring preload, and fluid is returned to the master cylinder.

Therefore, this whole process of clutch engagement or disengagement by pushing or releasing the clutch-pedal is the major cause of vibrations felt by the driver during clutch-operation.

Accordingly, the aforesaid axial movement of the flywheel due to the crankshaft bending are transferred through the clutch disc, clutch cover assembly, clutch release system (concentric slave cylinder (CSC), clutch tube/pipes, clutch master cylinder) to the clutch-pedal assembly, which is felt at the vehicle driver’s foot during the clutch-pedal actuation while engaging/disengaging the clutch, and are a constant discomfort to the driver.

These vibrations are usually at 0.5 order of the engine vibrations. Currently, hydraulic dampers are used in the clutch-release system for reducing the intensity of these clutch-pedal vibrations caused in the aforesaid manner.

However, the addition of the hydraulic dampers in the clutch release system increases the loss of travel which results in hard gear shifting caused due to incomplete clutch disengagement. This In turn leads to a reduced load-efficiency of the clutch release system. This results in higher pedal effort and poorer clutch-pedal characteristics experienced by the vehicle driver. The addition of hydraulic dampers also increases the overall weight and cost of the conventional clutch-release system.

Therefore, there is an existing need for filtering and dampening the axial vibrations of the engine by the clutch-cover assembly and eliminating the conventional hydraulic dampers used in the clutch release system, as discussed above, for not only improving the clutch release system efficiency but also reducing the weight and the overall cost thereof.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a clutch-release system with an improved clutch-cover assembly for automobiles.

Another object of the present invention is to provide an improved clutch-cover assembly to successfully filter the axial vibrations in the automotive engines.

Still another object of the present invention is to provide an improved clutch-cover assembly to efficiently dampen axial vibrations in automotive engines.

Yet another object of the present invention is to provide an improved clutch-cover assembly by eliminating the conventional hydraulic dampers used therein.

A further object of the present invention is to provide an improved, light-weight clutch system to filter/dampen axial vibrations in automotive engines.

A still another object of the present invention is to provide an improved clutch-cover assembly to filter and dampen axial vibrations in automotive engines.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE INVENTION

In accordance with the present invention, an improved light-weight, low-cost, clutch system with an efficient clutch cover assembly is provided. This improved clutch system comprises a cushion-spring in the clutch-cover assembly disposed between the cover-housing and the diaphragm thereof. This clutch system for damping axial vibrations emanating from the engine flywheel by its axial movement due to lateral movement of the crankshaft bending because of the engine firing impulses occurring in the engine-cylinders.

The improved clutch system configured in accordance with the present invention significantly enhances the driver’s comfort by efficiently dampening the vibrations felt at the clutch-pedal. This clutch system does not require any hydraulic dampers, which obviously increase the weight and cost of the existing clutch- system.

According to the present invention, based on the axial-vibration transfer-path, a compact cushion-spring mechanism is introduced in the clutch cover assembly. This compact cushion-spring mechanism is disposed in between the clutch-cover housing and its diaphragm without affecting the performance of the clutch system, and with minimal change therein.

It was observed that adapting the cushion-spring mechanism at other locations and sub-components of the clutch-cover assembly do not provide the desired result, because the clutch-cover housing is the only sub-component directly mounted on the flywheel and is present in the transfer-path of axial-vibrations leading to the diaphragm and clutch release system.

This way, the hydraulic dampers conventionally added in the existing clutch release system are successfully eliminated, since the axial vibrations are efficiently damped by the new configuration of the clutch-cover assembly with a cushion-spring mechanism discussed above.

SUMMARY OF INVENTION

In accordance with the present invention, there is provided a clutch system with an efficient and improved clutch-cover assembly for dampening of axial vibrations in automobile engines, the clutch cover assembly comprises:

• a clutch cover having a plurality of first holes on the closed end thereof;

• the clutch cover having a plurality of second holes on the closed end thereof;

• a diaphragm supported between the clutch cover and a pressure plate;

• a plurality of first rivets inserted through the plurality of first holes;

• a plurality of second rivets inserted through the plurality of second holes;

• a respective fulcrum wire spring mounted circumferentially outside the plurality of first rivets and disposed on either side of the diaphragm;

• a plurality of cushion springs disposed between the clutch cover and the diaphragm;

wherein the plurality of cushion springs is configured for dampening of axial vibrations transferred from the flywheel mounted on the crankshaft via the clutch and the release system thereof to the clutch-pedal assembly of the automobile.

Typically, the plurality of second holes is disposed circumferentially away from the plurality of first holes.

Typically, the plurality of first rivets have a larger diameter and length than the plurality of second rivets.

Typically, the diaphragm comprises a plurality of holes axially aligned with the plurality of first holes.

Typically, the first end of the plurality of cushion springs is mounted inside the clutch cover by means of the plurality of second rivets.

Typically, the outer circumferential end of the diaphragm is disposed between the second free-end of the plurality of cushion springs and the pressure plate.

Typically, the plurality of cushion springs comprises:

• a first flanged-end having a hole at the center thereof; and

• a second profiled-end connected to the first flanged-end by means of a profiled curvature;

wherein the flanged-end is mounted within the clutch cover by means of the plurality of second rivets inserted through the plurality of second holes in the clutch cover.

Typically, the outer end of the fulcrum wire spring is disposed between the plurality of first rivets and plurality of second rivets.

Typically, the outer diameter of the fulcrum wire spring is smaller than the outer diameter of the diaphragm.

In an embodiment of the present invention, the clutch-cover assembly comprises:

• the plurality of second holes disposed circumferentially away from the plurality of first holes;

• the plurality of first rivets have a larger diameter and length than the plurality of second rivets;

• the diaphragm comprises a plurality of holes axially aligned with the plurality of first holes;

• the plurality of cushion springs mounted with the first end thereof fixed inside the clutch cover by means of the plurality of second rivets;

• the diaphragm disposed with the outer circumferential end thereof pressed between the second free-end of the plurality of cushion springs and the pressure plate;

• a respective fulcrum wire spring mounted circumferentially outside the plurality of first rivets and disposed on either side of the diaphragm;

• each of the plurality of cushion springs have a first flanged-end with a hole at the center thereof, disposed between the clutch cover and the diaphragm, and a second profiled-end connected to the flanged-end by means of a profiled curvature;

• the first flanged-end mounted within the clutch cover by means of the plurality of second rivets inserted through the plurality of second holes in the clutch cover;

• the fulcrum wire spring with the outer end thereof disposed between the plurality of first rivets and plurality of second rivets; and

• the outer diameter of the fulcrum wire spring is smaller than the outer diameter of the diaphragm;

wherein the plurality of cushion springs is configured for dampening of axial vibrations transferred from the flywheel mounted on the crankshaft via the clutch assembly to the clutch-pedal assembly of the automobile.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1 shows the main components of a typical clutch system in an automobile.

Figure 2 shows a cross-sectional view of the conventional clutch cover assembly with its interface parts

Figure 3 shows a typical engine to clutch-pedal vibration generation and transfer-path in an automobile.

Figure 4 shows a schematic view of the conventional clutch-release assembly fitted with a hydraulic damper between the concentric slave cylinder and the master cylinder as depicted in Figure 3.

Figure 5 shows the improved clutch system with a lightweight, low-cost and efficient clutch cover assembly configured in accordance with the present invention and depicted with a clutch cushion spring positioned between clutch cover housing and diaphragm in which the cushion spring is riveted on the clutch cover housing on one end and at other end it is pre loading the diaphragm
Figure 6 shows a cross section view of improved clutch cover assembly.

Figure 7 shows an enlarged and exploded view of the clutch-cover assembly (Figure 4) configured in accordance with the present invention.

Figure 8 shows a clutch cushion spring for the improved clutch-release system configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following, an improved clutch cover assembly with a light-weight, low-cost, efficient clutch system configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention.

Figure 1 shows the main components of a typical hydraulic clutch-release system in an automobile. It includes a clutch-pedal CP connected to a master cylinder MC supplied with hydraulic fluid stored in a fluid tank FT. The master cylinder MC is also connected via a fluid pipe FP to a concentric slave cylinder CSC. Clutch cover assembly CA has a diaphragm spring DS to move the clutch release bearing forward/backward to engage/disengage the clutch. Now, when the clutch-pedal CP is depressed, a plunger (not shown) is pushed into the bore of master cylinder MC and the valve disposed at the end of this bore closes the outlet to hydraulic fluid tank FT, and this plunger movement pushes hydraulic fluid from fluid tank FT to the concentric slave cylinder CSC and its piston moves the clutch release bearing (not shown) for disengaging the clutch. On the contrary, on releasing the clutch-pedal CP, the concentric slave cylinder CSC piston is reversed due to the diaphragm spring, and hydraulic fluid returns to the master cylinder MC. However, this clutch engagement/disengagement by pushing/releasing the clutch-pedal CP causes substantial vibrations which are felt by the driver.
Figure 2 shows a cross section view of clutch cover assembly with its interface parts in an automotive vehicle. Here, main components of the clutch cover assembly CA are shown, which include a clutch cover CC covering the diaphragm D supported on the pressure plate. A concentric slave cylinder CSC is in contact with the diaphragm D. Flywheel FW is moved due to axial vibrations AV and these vibrations V1 are transferred to the slave cylinder CSC as shown by red arrow V2 therebetween.

Figure 3 shows a typical engine to clutch-pedal vibration generation and transfer-path in an automotive vehicle. Here, a crankshaft CS connected to one of the piston-cylinder PC of an automobile engine is shown in a bent state B due to the engine firing impulses produced therein. As a result of this crankshaft CS bending B, the flywheel FW connected to the crankshaft CS experiences axial vibrations, which are transferred to the concentric slave cylinder CSC and which in turn are transferred VT to reach the clutch-pedal CP via fluid pipe FP and master cylinder MC in the manner described above. The axial vibrations AV of flywheel FW due to the bending B of the crankshaft CS are transferred through the clutch disc, clutch cover assembly, clutch release system (concentric slave cylinder CSC, fluid pipes FP, clutch master cylinder MC) to the clutch-pedal CP assembly, which is felt at the vehicle driver’s foot during the clutch-pedal CP actuation while engaging/disengaging the clutch, and constantly causes driver discomfort.

Figure 4 shows a schematic view of the conventional clutch-release assembly fitted with a hydraulic damper HD between the concentric slave cylinder CSC and master cylinder MC as depicted in Figure 3.

Figure 5 shows the positioning of a clutch cushion spring in the improved clutch-release system configured in accordance with the present invention. The main difference from the conventional clutch-release assembly shown in Figure 2 is that a cushion spring 20 is placed between the clutch cover 12 covering the diaphragm 16 supported on the pressure plate 50. A concentric slave cylinder 18 is in contact with this diaphragm 16. When flywheel 10 moves due to axial vibrations AV, these vibrations V1 are damped and filtered by this cushion spring 20 and therefore, the vibrations V3 transferred to slave cylinder 18 are substantially damped. This in turn leads to a significant reduction in the vibrations transferred to the clutch-pedal CP and thus reducing the discomfort of the driver pressing the clutch pedal CP while engaging/disengaging the clutch of the automobile.

Figure 6 shows an improved, lightweight, low-cost and efficient clutch-cover assembly CA configured in accordance with the present invention for clutch system. The clutch-cover assembly CA includes a clutch-cover housing 30 including a plurality of fulcrum wire springs 40 fitted about diaphragm 16 by means of a plurality of first rivets 22 inserted through a respective plurality of first holes 25. The plurality of fulcrum wire springs 40 is disposed between the cover housing 30 and the pressure plate 50. A plurality of cushion springs 20 is fitted within cover housing 30 by means of plurality of second rivets 32 inserted through a respective plurality of second holes 35. The cushion springs 20 are circumferentially disposed away from the first rivets 22 for filtering and dampening the axial vibrations AV transferred from flywheel (Figure 4) to clutch assembly CA.

Figure 7 shows an enlarged and exploded view of the clutch-cover assembly configured in accordance with the present invention (Figure 6). It includes cover housing 30 with plurality of first rivets 22 and pressure plate 50. Diaphragm 16 is disposed between two fulcrum wire springs 40 and assembled between the cover housing 30 and pressure plate 50 by means of a plurality of first rivets 22. A plurality of cushion springs 20 are also fitted with one flanged end 24 thereof supported on the cover housing 30 and the other profiled end 26 thereof supported on the diaphragm 16 for cushioning thereof to filter and dampen the axial vibrations AV transferred from the flywheel FW due to the bending of the crankshaft CS because of the firing impulses occurring in the automotive engine piston-cylinder PC. The shape of cushion springs 20 is described below in more details with reference to Figure 8.

Figure 8 shows a clutch cushion spring 20 (Figure 7) for the improved clutch-cover assembly configured in accordance with the present invention. The cushion spring 20 includes an aperture 23 on the first flanged-end 24 thereof to be fitted on the cover housing 30 by means of plurality of second rivets 32. The cushion ring 20 also includes a second profiled-end 26 for contacting the outer periphery of the diaphragm 16 with a predefined preload thereon. The first and second end 24, 26 of the cushion spring 20 are connected by another profiled curvature 21 for imparting a flexible bending thereof to enable an efficient filtering and dampening of the axial vibrations AV received from the flywheel FW for preventing and/or reducing the discomfort to the driver due to clutch-pedal CP vibrations.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The improved clutch cover assembly in accordance with the present invention offers the following advantages:

• Enhanced driver-comfort due to effective vibration- dampening.

• Improved efficiency of the clutch release system.

• Elimination of the hydraulic dampers.

• Better clutch characteristics and clutch-pedal feel.

• Low clutch system weight by eliminating hydraulic dampers in clutch release system.

• Low-cost solution for vibration- dampening.
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 distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

Terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. , Claims:We claim:

1. A clutch system with lightweight clutch cover assembly for dampening of axial vibrations in automobile engines, the clutch cover assembly comprises:

• a clutch cover (30) having a plurality of first holes (25) on the closed end thereof;

• said clutch cover (30) having a plurality of second holes (35) on the closed end thereof;

• a diaphragm (16) supported between said clutch cover (30) and a pressure plate (50);

• a plurality of first rivets (22) inserted through said plurality of first holes (25);

• a plurality of second rivets (32) inserted through said plurality of second holes (35);

• a respective fulcrum wire spring (40) mounted circumferentially outside said plurality of first rivets (22) and disposed on either side of said diaphragm (16);

• a plurality of cushion springs (20) disposed between said clutch cover (30) and said diaphragm (16);

wherein said plurality of cushion springs (20) is configured for dampening of axial vibrations transferred from the flywheel mounted on the crankshaft via said clutch and the release system thereof to the clutch-pedal assembly of said automobile.
2. The clutch-cover assembly as claimed in claim 1, wherein said plurality of second holes (35) is disposed circumferentially away from said plurality of first holes (25).

3. The clutch-cover assembly as claimed in claim 1, wherein said plurality of first rivets (22) has a larger diameter and length than said plurality of second rivets (32).

4. The clutch-cover assembly as claimed in claim 1, wherein said diaphragm (16) comprises a plurality of holes (15) axially aligned with said plurality of first holes (25).

5. The clutch-cover assembly as claimed in claim 1, wherein the first end of said plurality of cushion springs (20) is mounted inside said clutch cover (30) by means of said plurality of second rivets (35).

6. The clutch-cover assembly as claimed in claim 1, wherein the outer circumferential end of said diaphragm (16) is disposed between the second free-end of said plurality of cushion springs (20) and said pressure plate (50).

7. The clutch-cover assembly as claimed in claim 1, wherein said plurality of cushion springs (20) comprises:

• a first flanged-end (24) having a hole (23) at the center thereof; and

• a second profiled-end (26) connected to said first flanged-end (24) by means of a profiled curvature (21);

wherein said flanged-end (24) is mounted within said clutch cover (30) by means of said plurality of second rivets (32) inserted through said plurality of second holes (35) in said clutch cover (30).
8. The clutch-cover assembly as claimed in claim 1, wherein the outer end of said fulcrum wire spring (40) is disposed between said plurality of first rivets (22) and plurality of second rivets (32).

9. The clutch-cover assembly as claimed in claim 8, wherein the outer diameter of said fulcrum wire spring (40) is smaller than the outer diameter of said diaphragm (16).

10. The clutch-cover assembly as claimed in claim 1, wherein said clutch-cover assembly comprises:

• said plurality of second holes (35) disposed circumferentially away from said plurality of first holes (25);

• said plurality of first rivets (22) have a larger diameter and length than said plurality of second rivets (32);

• said diaphragm (16) comprises a plurality of holes (15) axially aligned with said plurality of first holes (25);

• said plurality of cushion springs (20) mounted with the first end thereof fixed inside said clutch cover (30) by means of said plurality of second rivets (32);

• said diaphragm (16) disposed with the outer circumferential end thereof pressed between the second free-end of said plurality of cushion springs (20) and said pressure plate (50);

• a respective fulcrum wire spring (40) mounted circumferentially outside said plurality of first rivets (22) and disposed on either side of said diaphragm (16);

• each of said plurality of cushion springs (20) have a first flanged-end (24) with a hole (23) at the center thereof, disposed between said clutch cover (30) and said diaphragm (16), and a second profiled-end (26) connected to said flanged-end (24) by means of a profiled curvature (21);

• said first flanged-end (24) mounted within said clutch cover (30) by means of said plurality of second rivets (32) inserted through said plurality of second holes (35) in said clutch cover (30);

• said fulcrum wire spring (40) with the outer end thereof disposed between said plurality of first rivets (22) and plurality of second rivets (32); and

• the outer diameter of said fulcrum wire spring (40) is smaller than the outer diameter of said diaphragm (40);

wherein said plurality of cushion springs (20) is configured for dampening of axial vibrations transferred from the flywheel mounted on the crankshaft via said clutch assembly to the clutch-pedal assembly of said automobile.

Dated this 31st day of May 2023.

Digitally / e-Signed by:

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043.