Patent Application
20170370423
The present disclosure relates to friction plates for clutches and more particularly to friction plates for friction clutches having interrupted or discontinuous patterns of friction material on the faces of the clutch plates.
The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Friction clutch assemblies are extraordinarily common components of mechanical power transmission devices. Wherever a rotating, torque supplying member must be coupled to an initially non-rotating member a friction clutch will generally be utilized. The friction clutch typically includes one or more plates rotationally coupled to a first member having friction material on both faces which are interleaved with plates such as reaction plates which are rotationally coupled to a second member and which lack such material. The interleaved plates are compressed by a linear actuator and, when compressed, torque is transmitted through the device.
In the prior art, the friction material on the clutch plates takes the form of two bands of equal inside and outside diameters that are secured to opposite faces of the clutch plate, typically by an adhesive. The bands may be fabricated of clutch paper or of a more specialized material that provides certain, desirable frictional characteristics. While simple and inexpensive, this friction material configuration is accompanied by certain shortcomings. First of all, a continuous band of material may interfere with radial flow of cooling and lubricating fluid in a wet clutch. Second of all, because the outside edge of the band of friction material is generally adjacent to the outside edge of the clutch plate, uneven pressure and loading on the plates of the clutch may result. Such uneven loading can result in both reduced torque capacity and service life.
The present invention is directed to improving torque capacity and service life by addressing this problem.
The present invention provides a friction plate having interrupted or discontinuous bands of friction material on its faces. The invention comprehends friction plates, typically fabricated of metal, having friction material that is disposed in concentric bands disposed in interrupted or discontinuous segments or a combination of both. In a first embodiment, the friction material is arranged in two concentric bands on each face, an inner band having a smaller radial width radially spaced from an outer band having a larger radial width. In a second embodiment, the inner band is replaced with a plurality of discontinuous sections or segments wherein their circumferential separation is greater than their circumferential length. A third embodiment is similar to the second embodiment except that the inner, discontinuous segments have a circumferential length greater than their circumferential separation. Friction plates having either inner, female splines or outer, male splines as well as a friction clutch assembly incorporating friction plates incorporating the present invention are also disclosed. Friction plates embodying the present invention provide improved lubrication circulation in wet clutches and thus improved heat dissipation as well as enhanced operation.
Thus it is an aspect of the present invention to provide a friction plate having interrupted or non-continuous bands of friction material on its faces.
It is a further aspect of the present invention to provide a friction plate having multiple, radially spaced apart bands of friction material on its faces.
It is a still further aspect of the present invention to provide a friction plate having circumferentially interrupted or spaced apart segments or section of friction material on its faces.
It is a still further aspect of the present invention to provide a friction plate having a combination of multiple spaced apart bands and discontinuous segments of friction material on its faces.
It is a still further aspect of the present invention to provide a friction clutch assembly incorporating friction plates having interrupted or non-continuous bands of friction material on their faces.
Further aspects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
With reference to
An identical pattern or arrangement of friction material is disposed on both front and back surfaces 18A and 18B and thus only the complete front surface 18A is illustrated and will be described, it being understood that the back side, surface or face 18B is identical to the front side, surface or face 18A. On the front face 18A of the friction plate 10 resides a continuous first or outer band or annulus of friction material 20 having an outer circumferential edge 22 disposed just radially inside and adjacent the minor diameter of the splines or teeth 16 on the periphery of the friction plate 10. Similarly, just inside and adjacent the inner edge 24 of the friction plate 10 resides a continuous second or inner band or annulus of friction material 26. The friction material utilized here and in the other disclosed embodiments may be either what is commonly referred to as friction paper or may be one of numerous other conventional or proprietary materials commonly utilized in friction clutch assemblies which is secured to the front and back surfaces 18A and 18B of the disc or plate 12 by an adhesive.
The width of the first band or annulus of friction material 20 is preferably approximately twice as wide as the width of the second band or annulus of friction material 26. A circular space or region 28 radially separates the inner and outer bands 20 and 26 of friction material. Preferably, the width of the circular space or region 28 between the bands 20 and 26 of friction material is approximately as wide as the width of the second, inner band 26 of friction material. As noted above, the inner and outer diameters of the bands 20 and 26 are the same width and spacing on each face 18A and 18B so that axial forces applied to the friction material 20 and 26 do not distort, i.e., warp, the friction plate 10.
Referring now to
An identical pattern or arrangement of friction material is disposed on both front and back surfaces 48A and 48B and thus only the complete front surface 48A is illustrated and will be described, it being understood that the back side, surface or face 48B is identical with regard to both spacing and arrangement of the friction material to the front side, surface or face 48A. On the front face 48A of the friction plate 40 resides a continuous first or outer band or annulus of friction material 50 having an outer circumferential edge 52 disposed just inside and adjacent the minor diameter of the splines or teeth 46 on the periphery of the friction plate 40. Similarly, just inside and adjacent the inner edge 54 of the friction plate 40 resides an interrupted or discontinuous second or inner band or annulus of friction material comprising a plurality of equally circumferentially spaced apart arcuate segments or sections 56.
The width of the first band or annulus of friction material 50 is preferably approximately twice as wide as the width of the arcuate segments or sections of friction material 56. While six segments or sections 56 each extending over approximately 10° are illustrated in
The segments or sections 56 are spaced radially inwardly from the first continuous band or annulus of friction material 50. Preferably, the width of the radial spaces 58 between the band or annulus 50 of friction material and the segments or sections 56 of friction material is approximately as wide as the width of the segments or sections 56. As noted above, the width, and inner and outer diameters of the first continuous band 50 of friction material and the number, width, inner and outer diameters and placement of the discontinuous segments or sections 56 are the same on each face 48A and 48B so that axial forces applied to the friction material 50 and 56 do not distort, i.e., warp, the friction plate 40.
Referring now to
An identical pattern or arrangement of friction material is disposed on both front and back surfaces 68A and 68B and thus only the complete front surface 68A is illustrated and will be described, it being understood that the back side, surface or face 68B is identical with regard to both spacing and arrangement of the friction material to the front side, surface or face 68A. On the front face 68A of the friction plate 60 resides a continuous first or outer band or annulus of friction material 70 having an outer circumferential edge 72 disposed just inside and adjacent the minor diameter of the splines or teeth 66 on the periphery of the friction plate 70. Similarly, just inside and adjacent the inner edge 74 of the friction plate 70 resides an interrupted or discontinuous second or inner band or annulus of friction material comprising a plurality of equally circumferentially spaced apart arcuate segments or sections 76.
The width of the first band or annulus of friction material 70 is preferably approximately twice as wide as the radial width of the arcuate segments or sections 76 of friction material. While five segments or sections 76 each extending over approximately 40° are illustrated in
The segments or sections 76 are spaced radially inwardly from the first continuous band or annulus of friction material 70. Preferably, the width of annular spaces 78 between the continuous band or annulus of friction material 70 and the segments or sections 76 of friction material is at least as wide as the width of the segments or sections 76. As noted above, the width and inner and outer diameters of the continuous band 70 and the number, width, inner and outer diameters and placement of the discontinuous segments or sections 76 are the same on each face 68A and 68B of the friction plate 60 so that axial forces applied to the friction material 70 and segments or sections 76 of friction material do not distort, i.e., warp, the friction plate 70.
Referring now to
A typical and exemplary friction pack clutch assembly having the latter configuration and incorporating the present invention is illustrated and generally designated by the reference number 100. The friction pack clutch assembly 100 includes an input hub 102 which is connected to and driven by a source of torque such as a shaft, quill, or clutch or brake component of a transmission, transfer case, differential of other torque carrying member of, for example, a motor vehicle powertrain (not illustrated). The input hub 102 includes axially extending male splines or teeth 104 which are complementary to and engage female splines or teeth 106 on a plurality of first or friction plates 108. The plurality of first or friction plates 108 each includes friction material 110 disposed on both faces which may be arranged according to any of the three embodiments of the present invention 20, 40 and 60 described directly above. The plurality of first or friction plates 108 are interleaved with a plurality of second or reaction plates 112. The reaction plates 112 are preferably fabricated of steel or aluminum and include a plurality of male splines or teeth 114 disposed about their peripheries which engage and drive complementarily configured axially extending female splines or teeth 116 on a clutch housing 120.
The clutch housing 120 may be either rotatable or stationary. On a first end of the interleaved friction clutch plates 108 and reaction plates 112, the clutch housing 120 includes an inwardly extending circular web or stop 122 and an adjacent annular backing plate 124 against which the interleaved plates 108 and 112 are compressed. On a second or opposite end of the interleaved plates 108 and 112 is an apply plate 126 which is acted upon by a piston 128 of a hydraulic, electric or pneumatic operator or actuator 130. Axial force from the operator or actuator 130 is applied across the apply plate 126, compressing the interleaved plates 108 and 112 against the backing plate 124 thereby transmitting torque through the friction pack clutch assembly 100.
Although the term “input hub” has been utilized above and the description, for reasons of clarity and simplicity, has assumed that when the clutch is engaged, torque is transmitted from the input hub 102 to the clutch housing 120, it should be appreciated that (a) not only torque may be as readily transmitted from the housing 120 of the friction pack clutch assembly 100 to the hub 102 (b) but also the assembly 100 may readily function as a brake when, as noted above, the clutch housing 120 is stationary.
It will be appreciated that friction clutch plates 20, 40 and 60 according to the present invention provide improved lubrication flow from the inner diameter of the clutch plates to their outer diameter by virtue of the radial and circumferential spacing of the bands and segments of friction material on the faces or surfaces of the plates. By providing improved lubrication flow, first of all, heat dissipation is improved and, second of all, the repeatability and proportionality of clutch engaging force versus torque transfer and thus the control of delivered torque is also improved.
The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
