The invention relates generally to clutch assemblies, and, more particularly, to an improved adjustment tab for an adjustment means within a clutch assembly.
Clutch assemblies are used in motor vehicles between an engine and a transmission. A motor vehicle typically includes a single clutch or a dual clutch. In a motor vehicle with a single clutch, the clutch is coupled between the crankshaft and the input shaft of the transmission, thereby transferring torque from the crankshaft to the transmission. In a motor vehicle with a dual clutch, torque is transferred to two transmission input shafts arranged coaxially in relation to the other. Over time, the friction disc in the clutch assembly becomes increasingly worn. In order to compensate for the wear of the friction disc, the clutch assembly includes a means for adjusting the clutch assembly in relation to the amount of wear of the friction disc. The adjusting means includes at least one preloaded adjustment ring and a preloaded sensor ring with ramps provided between a clutch housing and lever arms. The adjustment and sensor rings are preloaded in a circumferential direction with pressure springs such that when the clutch disc becomes increasingly worn, the adjustment ring is forced to move in order to compensate the gap created between the pressure plate and the clutch disc.
The adjusting means is activated by sensor devices, which measure either travel or an actuating force exerted by the lever arms. The sensor devices include a clamp spring and adjustment tabs. The clamp spring is fixedly secured to the housing of the clutch assembly and operatively arranged to engage the adjustment tabs.
As described above, over time, the friction disc of the clutch assembly becomes worn; thus, the distance between the pressure plate and the friction disc increases. This increase in distance causes an increase in required engagement travel on the lever arms necessary to engage the pressure plate with the clutch disc. The adjustment tabs exert a predefined load on a sensor ring and sense the amount of wear or distance between the pressure plate and the friction disc. When the distance between the pressure plate and the friction disc increases, the lever arms engage the adjustment tab, then, the adjustment tab is lifted off, releasing the sensor ring. Since the adjustment tabs are also fixedly secured to the clamp spring, the axial movement of the lever arms causes the adjustment tabs and the clamp spring to undergo a travel or distance equal to the increase in distance between the pressure plate and the worn friction disc.
To compensate for the increased travel or distance between the adjustment tabs and the sensor ring, and thus an increase in the distance necessary for the pressure plate to engage with the friction disc, the sensor ring moves axially to reengage with the adjustment tabs. As the sensor ring reengages with the adjustment tabs, the adjuster ring simultaneously moves axially a distance equal to the distance traveled by the sensor ring. The adjustment means (comprising the adjuster ring, the sensor ring, the clamp spring, the adjustment tabs and the lever arms) moves axially a distance equivalent to that traveled by the adjuster ring and the sensor ring, such that the distance between the pressure plate and the friction disc returns to its initial predetermined equilibrium position.
A typical adjustment tab is disclosed in German Patent Application No. DE 102009053479 (Ruehle) filed Nov. 16, 2009. The clutch assembly disclosed includes an automatic readjusting device between the lever elements and the housing. The readjusting device described includes readjustment pieces which are secured to a sensor ring by rivets. However, due to the mass of the adjustment pieces and the structure of the assembly, unwanted rotation occurs.
Another adjustment tab is disclosed in German Patent Application No. DE 102011102261 (Miguel) filed May 23, 2011. The friction clutch disclosed in this application includes a diaphragm spring for actuating a pressure plate and an adjustment means secured to a clamping spring by a screw. However, due to the mass of the adjustment means and the structure of the assembly, unwanted rotation occurs.
The unwanted rotation described herein is demonstrated in
Typical adjustment tabs 50A, 50B, 50C are secured to clamp spring 51 by screws 52A, 52B, 52C, respectively, and bushings 53A (shown in
When typical adjustment tab 50A and clamp spring 51 are secured together, clamp spring 51 exerts a downward force to the sensor ring 54. As best shown in
Unfortunately, while clutch assembly 40 rotates about axis 41, due to the centrifugal force, each assembled typical adjustment tab 50A, 50B, 50C and clamp spring 51 produce an unwanted outward rotation in the direction of the arrow shown in
Thus, there has been a long-felt need for an improved adjustment tab for a clutch assembly which, when assembled with a clamp spring of the clutch assembly, reduces the amount of unwanted outward rotation.
The invention is a clutch assembly for transferring a torque between a flywheel of an engine and a transmission in a motor vehicle, the clutch assembly comprising a housing, a pressure plate fixedly secured to the housing, the pressure plate operatively arranged to cause a friction clutch disc to engage the flywheel, wherein the pressure plate is arranged for rotation about an axis of rotation, wherein the pressure plate is axially movable relative to the axis of rotation, an adjustment means operatively arranged to adjust travel of the pressure plate and the friction clutch disc, and a plurality of lever arms operatively arranged to provide a force within the clutch assembly, the adjustment means further comprising: an adjustment tab comprising: a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage with the adjustment means of the clutch assembly; a first non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms; and, a second non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms.
The invention also includes an improved adjustment tab for a self-adjusting clutch comprising a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage an adjustment means of the clutch; a first non-linear member emanating upwardly from the base member and arranged to clasp at least one of a plurality of lever arms; and, a second non-linear member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms.
Furthermore, the invention includes a clutch assembly for transferring a torque between a flywheel of an engine and a transmission in a motor vehicle, the clutch assembly comprising a housing, a pressure plate fixedly secured to the housing, the pressure plate operatively arranged to cause a friction clutch disc to engage the flywheel, wherein the pressure plate is arranged for rotation about an axis of rotation, wherein the pressure plate is axially movable relative to the axis of rotation, an adjustment means operatively arranged to adjust travel of the pressure plate and the friction clutch disc, and a plurality of lever arms operatively arranged to provide a force within the clutch assembly, the adjustment means further comprising an adjustment tab/clamp spring assembly including an adjustment tab coupled to a clamp spring, wherein the clamp spring is operatively arranged to engage the adjustment means of the clutch assembly, and wherein the adjustment tab/clamp spring assembly has a center of mass which is co-planar with the clamp spring.
Additionally, the invention includes an improved adjustment tab for a self-adjusting clutch comprising a base member having an integral engagement means operatively arranged to engage a clamp spring, the clamp spring operatively arranged to engage an adjustment means of the clutch, a first member emanating upwardly from the base member and arranged to clasp at least one of a plurality of lever arms, and, a second member emanating upwardly from the base member and arranged to clasp at least one of the plurality of lever arms.
A general object of the invention is to provide an improved adjustment tab for a clutch assembly which, when the improved adjustment tab is assembled with a clamp spring of the clutch assembly, results in a reduced amount of unwanted outward rotation.
A further object of the invention is to provide an improved adjustment tab which can be integrally secured to a clamp spring of a clutch assembly.
Another object of the invention is to provide an improved adjustment tab which has a reduced mass and, when the improved adjustment tab is coupled to a clamp spring of a clutch assembly, the improved adjustment tab and clamp spring exhibit an improved center of mass.
These and other objects, features and advantages of the present invention will become readily apparent upon a review of the following detailed description of the invention, in view of the drawings and appended claims.
Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. It is to be understood that the invention as claimed is not limited to the disclosed aspects.
Furthermore, it is understood that this patent is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention as claimed.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention.
The term “S”-shaped used herein refers to the general shape of non-linear members 113 and 114 and the term refers generally to the shape of a sigmoid curve. However, the term should not be so limited and non-linear members 113 and 114 can assume a variety of non-linear or linear shapes, for example, stepped shapes.
To clarify the spatial terminology, objects 4, 5, and 6 are used. Surface 7 of object 4 forms an axial plane. For example, axis 1 is congruent with surface 7. Surface 8 of object 5 forms a radial plane. For example, radius 2 is congruent with surface 8. Surface 9 of object 6 forms a circumferential surface. For example, circumference 3 is congruent with surface 9. As a further example, axial movement or disposition is parallel to axis 1; radial movement or disposition is orthogonal to axis 2, and circumferential movement or disposition is parallel to circumference 3. Rotation is described herein with respect to axis 1.
The adverbs “axially,” “radially,” and “circumferentially” are used with respect to an orientation parallel to axis 1, radius 2, or circumference 3, respectively. The adverbs “axially,” “radially,” and “circumferentially” are also used with respect to orientation parallel to respective planes.
In
Due to the “S”-shape of non-linear members 113 and 114, non-linear members 113 and 114 could have a spring-like force when a load is applied to them. This spring-like force could help secure improved adjustment tabs 110A, 110B, and 110C to clamp spring 111. Since base portion 112 has a width that is less than the width of clamp spring 111, non-linear members 113 and 114 apply a force back onto clamp spring 111.
As shown in
Improved adjustment tab 210A is illustrated in
When improved adjustment tab 210A is secured to clamp spring 211 (as shown in
Improved adjustment tab 310A is shown in
The overall mass of improved adjustment tab 310A is approximately 1.94 grams although it should be appreciated that the mass of improved adjustment tab 310A may vary and is not intended to limit the scope of the claims. When improved adjustment tab 310A is secured to clamp spring 311 (as shown in
A clutch assembly incorporating improved adjustment tabs 110A, 210A, 310A can be actuated via electric or hydraulic means.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/954,886, filed Mar. 18, 2014, which application is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61954886 | Mar 2014 | US |