JP6306877B2 - Multi-plate brake - Google Patents

Description

  The present invention relates to a multi-plate brake that uses a disc spring as a return spring of a piston.

  For the purpose of braking or torque transmission, a friction engagement device that frictionally engages an alternately provided friction plate and a mating member generally includes a hydraulic piston in order to realize the friction engagement. A configuration is employed in which the piston is operated by hydraulic pressure and the pusher plate of the mating member is pushed in the axial direction by a pressing portion that interlocks with the piston (including the case where the piston is provided). In addition, a spring (return spring) that pushes the piston back to the original position is provided to release the frictional engagement between the friction plate and the counterpart member when the hydraulic pressure is released. The friction engagement device having such a configuration is used as, for example, a clutch or a brake in a transmission of an automobile, and examples thereof include the following.

JP 2007-170442 A

  Patent Document 1 discloses an annular piston having a plurality of arc-shaped pressing portions provided on one surface at intervals in the circumferential direction and a circumferential direction of the piston between the pressing portions. A piston provided with a pin, and an annular spring retainer having substantially the same diameter as the piston, wherein a slit through which the pressing portion can pass is provided at a position corresponding to the pressing portion of the piston, and a position corresponding to the pin of the piston There is disclosed a friction engagement device including a spring retainer provided with a coil spring.

  On the other hand, the multi-plate brake 100 (only the main part in the radial direction is shown) shown in FIG. 4A is a plurality of counterparts that are spline-fitted inside the outer diameter wall part 134 of the case 130. A friction plate 142 attached to the hub 140 so as to be positioned between the member 132 and the mating member 132, and an arcuate pressing portion provided at intervals in the circumferential direction of the side surface facing the mating member 132 116 (see FIG. 4B), and between the piston 114 and the mating member 132, the annular piston 114 fitted in the hydraulic chamber 112, and the outer diameter wall portion 134 of the case 130. The disc spring 120 is secured inside by a snap ring 128. In the disc spring 120, one surface of the inner diameter side piece 126 is in contact with the piston 114 and urges the piston 114 toward the hydraulic chamber 112. As shown in FIG. 4B, the disc spring 120 (half in the radial direction is shown) is provided with a spline 122 on its outer diameter side as a detent, and a plurality of springs on the inner diameter side. The slit 124 is provided, and when the piston 114 moves in the axial direction, the pressing portion 116 provided in the piston 114 can press the pusher plate 132a of the mating member 132 through the slit 124.

  The friction engagement device shown in Patent Document 1 requires a spring retainer, a plurality of coil springs fixed to the spring retainer, pins provided on the piston, and the like, so that the number of parts is relatively large and the structure is complicated. For this reason, there exists a problem that the increase of an assembly man-hour and an increase in manufacturing cost will be caused, and there also exists a problem that the dimension of an axial direction becomes large mainly on the design of a coil spring.

  On the other hand, the multi-plate brake 100 can be made more compact in the axial direction than the coil spring type. However, since the disc spring 120 of the multi-plate brake 100 requires the slit 124, the spring constant is lower than that of the disc spring having no slit. In order to increase the spring constant and sufficiently urge the piston 114, it is conceivable to make the slit 124 as shallow as possible. However, the pressing portion 116 of the piston 114 is a friction surface when the brake is engaged with the pusher plate 132a. Since the surface area, the radial position, etc. must be determined so that the surface pressure distribution is as uniform as possible, this is limited. Under these constraints, in order to realize a load sufficient to urge the piston 114, the axial dimension from the contact point between the disc spring 120 and the snap ring 128 to the contact point between the disc spring 120 and the piston 113 is reduced. Increase the effective radial length R ′ of the disc spring (the dimension from the bottom of the slit 124 to the outer diameter end of the disc spring (excluding the spline 122)), or increase the plate thickness of the disc spring. Measures need to be taken. However, such a measure may be difficult in design and causes a problem that the space inside the disk spring in the radial direction is lost or the manufacturing cost of the disk spring increases.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a multi-plate brake having a small number of parts and compact in both the radial direction and the axial direction.

The present invention includes a cylindrical case and a rotatable hub;
A spline fit inside the outer diameter wall of the case, and a mating member including a pusher plate,
A friction plate attached to the hub and frictionally engaged with the mating member;
A hydraulic chamber provided inside the case;
A piston that is fitted in the hydraulic chamber and operates in the axial direction of the case by supplying hydraulic oil to the hydraulic chamber;
In conjunction with the piston, a pressing portion that presses the pusher plate in the axial direction of the case;
A disc spring which is inside the outer diameter wall portion of the case and is secured by a snap ring between the pusher plate and the piston and biases the piston to a position where the pressing portion and the pusher plate are not in contact with each other. In a multi-plate brake having
The above-mentioned problem has been solved by a multi-plate brake in which the disc spring has a closed through-hole through which the pressing portion penetrates within the range of the radial effective length of the disc spring.

According to the present invention, the disc spring has a closed through-hole (hereinafter referred to as “through-hole”) through which the pressing portion passes within the radial effective length of the disc spring , and the pressing portion penetrates. Since the mating member is pressed through the hole, there is no need to provide a slit on the inner diameter side of the disc spring, so the effective length in the radial direction (the dimension from the inner diameter end of the disc spring to the outer diameter end (excluding the spline)) Can be lengthened. Therefore, the present invention has a high spring constant and can easily achieve a necessary load as compared with a conventional disk spring of the type having a slit, and the radial length of the disk spring ( Since the radial dimension from the inner diameter end to the outer diameter end (including the spline) of the disc spring can be shortened, as a result, the overall multi-plate brake can be made compact in the radial direction and the axial direction. In addition, when the same outer diameter and spring constant as the disc spring of the type having a slit, the present invention can shorten the radial length of the disc spring, and can secure a large radial inner space. It is possible to improve the degree of freedom in layout design of components and the like disposed within the inner diameter of the disc spring. In addition, the manufacturing cost of the disc spring can be relatively reduced. Needless to say, it has the advantage that it can be made more compact in the axial direction and has fewer parts compared to a multi-plate brake using a return spring of a conventional coil spring.

  In addition, if the piston, the pressing portion, the disc spring, the mating member, and the friction plate are linearly provided along the outer diameter wall portion of the case, a large space is secured on the radially inner side. Therefore, it becomes easy to arrange other parts on the inner diameter side of the case.

  In addition, by providing a plurality of sets of pistons, pressing parts, disc springs, mating members, and friction plates in the axial direction, a multi-plate brake that can realize braking and release for different hubs, the axial direction, A compact layout can be achieved in both radial directions.

The longitudinal cross-sectional view which shows the principal part of the radial direction half of the multi-plate brake of 1st embodiment of this invention. The schematic diagram of the radial direction half which looked at the relation between the disc spring and press part of the multi-plate brake of a first embodiment of the present invention from the axial direction. The longitudinal cross-sectional view which shows the principal part of the radial direction half of the multi-plate brake of 2nd embodiment of this invention. (A) is the longitudinal cross-sectional view which shows the principal part of the radial direction half of the conventional multi-plate brake, (b) is the schematic of the radial direction half which looked at the relationship between the disk spring and the press part from the axial direction.

  An embodiment of the present invention will be described with reference to FIGS. However, the present invention is not limited to this embodiment.

  FIG. 1 is a longitudinal sectional view showing a main part of the radial half of the multi-plate brake according to the first embodiment of the present invention. The multi-plate brake 10 is symmetrical with respect to the rotation axis (not shown) of the hubs 40 and 40 '. In addition, since the other structure of the multi-plate brake 10 which is not shown in the drawing is the same as that of the conventional multi-plate brake, illustration and description are omitted.

  The case 30 of the multi-plate brake 10 has an outer diameter wall portion 34 positioned on the outer diameter side thereof, and a spline is provided on the inner side of the outer diameter wall portion 34, and in order from the piston 14 side, a pusher plate 32 a, An annular mating member 32 comprising an intermediate plate 32b and an end plate 32c is spline-fitted. An annular friction plate 42 attached to the outer peripheral side of the hub 40 is disposed between the mating members 32. Note that a friction material is usually attached to the friction plate 42. A hydraulic cylinder 18 that forms the hydraulic chamber 11 is provided inside the case 30, and the piston 14 is fitted into the hydraulic cylinder 18. The piston 14 is formed with a pressing portion 16 that interlocks therewith. The shape and radial position of the pressing portion 16 are appropriately determined in consideration of the surface pressure distribution of the friction surface when the brake is engaged with the pusher plate 32a. Further, the spline 22 (see FIG. 2) provided on the outer diameter side of the annular disc spring 20 is fitted inside the outer diameter wall portion 34 of the case 30 and is prevented from being removed by the snap ring 28. The disc spring 20 is disposed between the pusher plate 32 a and the piston 14. One surface on the inner diameter side of the disc spring 20 is in contact with a part on the inner diameter side of the piston 14, and the other surface on the outer diameter side is in contact with the snap ring 28. It can be urged in the direction of the chamber 11 (the direction opposite to the counterpart member 32). Here, the spring constant of the disc spring 20 is such that the disc spring 20 urges the piston 14 to a position where the pressing portion 16 and the pusher plate 32a are not in contact with each other, and the non-friction engagement state of the multi-plate brake 10 can be realized. Then, the relative positions of the disc spring 20, the snap ring 28, and the piston 14 are determined.

The disc spring 20 of the multi-plate brake 10 has a through hole 24 through which the pressing portion 16 penetrates within the range of the radial effective length R of the disc spring 20 . The shape of the through hole 24 is determined according to the shape of the pressing portion 16. As shown in FIG. 2, since the disc spring 20 of the present invention has the through hole 24, it is necessary to provide a large slit for passing the pressing portion 16 on the inner diameter side as in the prior art. Absent. Therefore, compared to the disc spring provided with the slit, the radial effective length R (the dimension from the inner diameter end to the outer diameter end (excluding the spline 22) of the disc spring) can be made relatively long. Since a large load can be easily realized, the radial length S of the disc spring (the radial dimension from the inner diameter end to the outer diameter end of the disc spring) can be reduced to reduce the plate thickness. . For this reason, since the radial and axial compactness can be achieved as compared with a disc spring having a slit on the inner diameter side, the multi-plate brake as a whole can be compact in the radial and axial directions.

  Further, in the case of a disc spring having a slit on the inner diameter side, because of its structure, the pressing portion had to be designed to be positioned on the inner diameter side of the disc spring, that is, the inner diameter side of the case. In addition, if the disc spring 20 is provided with the through hole 24, the pressing portion 16 can be designed to be positioned on the relatively outer diameter side of the case 30. Therefore, the radial dimension T of the piston 14 and the hydraulic cylinder 18 can be reduced, and more space can be secured on the inner diameter side of the case 30.

  Next, the operation of the multi-plate brake 10 will be described. The pusher plate 32a and the intermediate plate 32b are movable in the axial direction, and the multi-plate brake 10 is configured to realize two states of a friction engagement state between the mating member 32 and the friction plate 42 and a non-friction engagement state. Has been. The state shown in FIG. 1 is a state in which the mating member 32 and the friction plate 42 are in a non-frictional engagement state, and when hydraulic oil is supplied to the hydraulic chamber 11 from this state (about the hydraulic oil supply path) The piston 14 moves in the axial direction (leftward in FIG. 1), compresses the disc spring 20, and the pressing portion 16 pushes the pusher plate 32a through the through hole 24 in the axial direction. The pressing force applied to the pusher plate 32a is transmitted to the end plate 32c through the friction plate 42 and the intermediate plate 32b, and the mating member 32 and the friction plate 42 are frictionally engaged. Thus, the friction engagement state of the multi-plate brake 10 is realized, and the rotation of the case 30 or the hubs 40 and 40 'is braked. When the hydraulic oil is released from this state, the disc spring 20 pushes the piston 14 back toward the hydraulic chamber 11 by the elastic force of the disc spring 20, so that the frictional engagement between the counterpart member 32 and the friction plate 42 is released. And return to the non-friction engagement state. Since the multi-plate brake 10 performs such an operation, it is preferable that the through hole 24 has a size that does not interfere with the pressing portion 16 in the entire range from the time when the disc spring 20 is not compressed to the time when it is compressed.

  Here, as shown in FIG. 1, the piston 14, the pressing portion 16, the disc spring 20, the mating member 32, and the friction plate 42 are linearly arranged along the outer diameter wall portion 34 of the case 30. With the configuration, it is possible to secure a maximum space on the inner diameter side of the case 30. This configuration is particularly effective when the present invention is applied as a multi-plate brake in which many parts need to be disposed on the inner diameter side of the case 30 as in the present embodiment.

  As shown in FIG. 1, the piston 14 ', the pressing portion 16', the disc spring 20 ', and the mating member 32' are different from the piston 14, the pressing portion 16, the disc spring 20, the mating member 32, and the friction plate 42. , And a set of friction plates 42 ′ can be provided side by side in the axial direction. In this case, it is possible to provide a multi-plate brake capable of realizing brake / release with respect to the separate hubs 40 and 40 ′ while maintaining the radial compactness. Of course, a piston, a pressing part, a disc spring, a mating member, and a friction plate may be further provided in the axial direction.

  In addition, as shown in FIG. 3, a cushion spring 36 can be provided between the pressing portion 16 and the mating member 32. Thereby, the impact at the time of the press part 16 and the other party member 32 contacting can be relieve | moderated.

  As described above, according to the present invention, it is possible to provide a multi-plate brake that has a small number of parts and is compact in both the radial direction and the axial direction.

DESCRIPTION OF SYMBOLS 10 Multi-plate brake 11 Hydraulic chamber 14 Piston 16 Press part 20 Belleville spring 24 Through-hole 30 Case 32 Counterpart member 32a Pusher plate 34 Outer diameter wall part 40 Hub 42 Friction plate

Claims (3)

A cylindrical case and a rotatable hub;
A spline fit inside the outer diameter wall of the case, and a mating member including a pusher plate,
A friction plate attached to the hub and frictionally engaged with the mating member;
A hydraulic chamber provided inside the case;
A piston that is fitted in the hydraulic chamber and operates in the axial direction of the case by supplying hydraulic oil to the hydraulic chamber;
In conjunction with the piston, a pressing portion that presses the pusher plate in the axial direction of the case;
A disc spring which is inside the outer diameter wall portion of the case and is secured by a snap ring between the pusher plate and the piston and biases the piston to a position where the pressing portion and the pusher plate are not in contact with each other. In a multi-plate brake having
The disc spring has a closed-type through hole through which the pressing portion penetrates within a range of a radial effective length of the disc spring.
Multi-plate brake.   The multi-plate brake according to claim 1, wherein the piston, the pressing portion, the disc spring, the mating member, and the friction plate are arranged linearly along the outer diameter wall portion of the case.   The multi-plate brake according to claim 1 or 2, wherein a plurality of sets of the piston, the pressing portion, the disc spring, the mating member, and the friction plate are provided in the axial direction.

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