JP2016031135A - Friction clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction clutch capable of improving torque capacity controllability at a time of switchover between engagement and disengagement.SOLUTION: A plurality of clutch plates 7 and a plurality of clutch discs 9 are disposed to be alternately aligned in a rotation center line direction. A piston 10 is provided on one side in the rotation center line direction with respect to the plurality of clutch plates 7 so that the piston 10 is movable in the rotation center line direction. Movement of this piston 10 causes a first clutch plate 7A to be pressed toward a second clutch plate 7B. The second clutch plate 7B is elastically urged toward the first clutch plate 7A by a spring 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wet multi-plate friction clutch.

  For example, a wet multi-plate friction clutch is used in an automatic transmission for a vehicle.

  In this automatic transmission, a plurality of shift stages are configured by selectively engaging and releasing a plurality of friction clutches. Therefore, when the gear position is changed (during gear shift), the engaged friction clutch may be released and another released friction clutch may be engaged. In order to suppress the shock generated at the time of switching, it is necessary to precisely control the torque capacity of these friction clutches. The torque capacity of the wet multi-plate friction clutch is determined by the hydraulic pressure applied to the piston and the number and diameter of the disks. Since the number and diameter of the disks are predetermined, the torque capacity of the friction clutch is controlled by controlling the hydraulic pressure applied to the piston.

JP 2013-130249 A

  Some automatic transmissions are configured to engage the same friction clutch at different gear positions. The friction clutch shared by the different shift speeds is designed (the number of disks and the diameter are determined) so that a sufficient torque capacity is secured at the low speed shift speed. Therefore, when switching the engagement / disengagement of the friction clutch at the high speed side gear stage, the torque capacity must be precisely controlled within a very small range relative to the maximum torque capacity of the friction clutch.

  However, in such a friction clutch, since the rate of change of the transmission torque capacity with respect to the change of the hydraulic pressure applied to the piston is large, the hydraulic pressure applied to the piston is very fine for precise control of the torque capacity at the time of engagement / release switching. There is a problem that the controllability at the time of switching is poor. Further, even when the hydraulic pressure applied to the piston is controlled very precisely when switching the engagement / release of the friction clutch, there is a risk that a shock may occur due to dimensional error of each part and variation of the friction coefficient.

  An object of the present invention is to provide a friction clutch capable of improving the controllability of torque capacity at the time of switching between engagement / release.

  In order to achieve the above object, a friction clutch according to the present invention includes a plurality of clutch plates arranged side by side in the rotation center line direction, a plurality of clutch disks arranged alternately in the direction of the rotation center line, and the clutch plates. A clutch plate that is provided so as to be movable in the direction of the rotation center line, and is arranged at the extreme end on one side in the direction of the rotation center line (hereinafter, simply referred to as “the extreme clutch plate” in this column) Except for the piston that presses the other side of the rotation center line in the direction of the rotational center line and the clutch plate at the end, and elastically biasing the clutch plate disposed on one side of the at least one clutch disk to one side And an urging member.

  According to this configuration, the plurality of clutch plates and the plurality of clutch disks are alternately arranged in the rotation center line direction. On one side of the rotation center line direction with respect to the plurality of clutch plates, a piston is provided so as to be movable in the rotation center line direction. Due to the movement of the piston to the other side, the outermost clutch plate is pressed to the other side. A clutch plate other than the outermost clutch plate and disposed on one side of at least one clutch disk is elastically biased to one side by a biasing member.

  Thus, until the pressing force applied from the piston to the outermost clutch plate exceeds the urging force of the urging member, the clutch plate on the other side from the urging force of the urging member is pushed by the piston. No pressure is transmitted, and only the clutch plate on one side of the clutch plate being urged by the urging member is pressed against the clutch plate by the pressing force from one side. At this time, the torque capacity (transmission torque capacity) of the friction clutch is arranged on one side of the number of clutch disks with which the clutch plate is pressed, that is, on the one side of the clutch plate on which the biasing member is biased. The size depends on the number of clutch disks. Therefore, the torque capacity of the friction clutch increases relatively gradually with respect to the increase of the pressing force by the piston. Therefore, when the friction clutch is engaged / released, the torque capacity can be precisely controlled by controlling the pressing force, and the occurrence of shock can be suppressed.

  When the pressing force applied from the piston to the outermost clutch plate increases and the pressing force exceeds the biasing force of the biasing member, the clutch plate biased by the biasing member by the pressing force moves to the other side. The clutch plate is pressed against the clutch disk on the other side. As a result, the torque capacity of the friction clutch becomes a magnitude corresponding to the number of all the clutch disks, and increases relatively steeply as the pressing force by the piston increases.

  As described above, when the friction clutch is shared by different gear stages of the automatic transmission, the engagement of the friction clutch at the high speed gear stage can be ensured while ensuring a sufficient torque capacity at the low speed gear stage. At the time of switching / release, it is possible to improve the controllability of torque capacity (pressing force by the piston).

  According to the present invention, it is possible to improve controllability of torque capacity at the time of switching between engagement / release.

It is sectional drawing which cut | disconnected the friction clutch which concerns on one Embodiment of this invention by the plane containing a rotation centerline, and shows the released state of a friction clutch. It is sectional drawing of the friction clutch shown by FIG. 1, and shows the engagement state of a friction clutch. It is a graph which shows the relationship between the hydraulic pressure of an oil chamber, and the torque capacity of a friction clutch.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 are cross-sectional views of the friction clutch 1 according to one embodiment of the present invention cut along a plane including the rotation center line C. FIG. 1 and 2 show only one side of the friction clutch 1 with respect to the rotation center line C. FIG.

  The friction clutch 1 is incorporated in, for example, an automatic transmission or a continuously variable transmission, and rotates the input shaft 2 which is a rotating body to which driving force is input, so that the input shaft 2 and the rotation center line C are shared. Used to transmit / cut off a rotating body (not shown).

  The friction clutch 1 includes a clutch drum 3 fixed to the input shaft 2 and a clutch hub 4 fixed to another rotating body.

  The clutch drum 3 has a direction substantially perpendicular to the rotation center line C, that is, a substantially disk-shaped disk portion 5 extending in the rotation radial direction, and a direction parallel to the rotation center line C on the outer peripheral side of the disk portion 5, that is, A cylindrical portion 6 having a substantially cylindrical shape extending in the rotation center line direction is integrally provided. A plurality of annular plate-like clutch plates 7 are arranged at intervals inside the cylindrical portion 6, and the outer peripheral portion of each clutch plate 7 is spline-fitted to the cylindrical portion 6.

  In this embodiment, as the clutch plate 7, the first clutch plate 7A, the second clutch plate 7B, the third clutch plate 7C, the fourth clutch plate 7D, the fifth clutch plate 7E, and the sixth clutch plate 7F are the disc portion 5. They are arranged in this order from the side. Hereinafter, when they are collectively referred to without distinction, they are simply referred to as “clutch plate 7”.

  The clutch hub 4 has a facing portion 8 that faces the cylindrical portion 6 of the clutch drum 3 in the rotational radial direction. Between the cylindrical portion 6 and the opposed portion 8, a plurality of annular plate-like clutch disks 9 are arranged alternately with the clutch plate 7 in the rotation center line direction. The inner periphery of the disk 9 is spline-fitted.

  In this embodiment, the clutch disk 9 includes a first clutch disk 9A, a second clutch disk 9B, a third clutch disk 9C, a fourth clutch disk 9D, and a fifth clutch disk 9E from the disc portion 5 side of the clutch drum 3. They are arranged in this order. Hereinafter, when they are collectively referred to without distinction, they are simply referred to as “clutch disk 9”.

  A piston 10 is provided inside the clutch drum 3 and at a position closer to the disc portion 5 side of the clutch drum 3 than the clutch plate 7 so as to be movable in the direction of the rotation center line. The piston 10 includes a substantially disc-shaped disc portion 11 extending in the rotational radial direction, a substantially cylindrical outer peripheral cylindrical portion 12 extending from the outer peripheral end of the disc portion 11 toward the clutch plate 7 in the rotational center line direction, and an outer periphery. It integrally has a hook-shaped pressing portion 13 that extends outward from the end of the cylindrical portion 12 on the clutch plate 7 side in the rotational radial direction. The pressing portion 13 faces the clutch plate 7 in the rotation center line direction.

  An inner peripheral portion of the disc portion 11 is bent and extended toward the clutch plate 7 side, and is bent and extended toward the input shaft 2 side. An end portion of the disc portion 11 extends between the disc portion 11 and the input shaft 2. An annular seal 14 for sealing is provided. Further, an annular seal 15 is provided on the outer periphery of the outer cylinder portion 12 to seal between the outer cylinder portion 12 and the clutch drum 3. The seals 14 and 15 are always in contact with the input shaft 2 and the clutch drum 3, respectively, regardless of the position of the piston 10. Thereby, an oil chamber 16 closed by the input shaft 2, the clutch drum 3, the piston 10 and the seals 14 and 15 is formed between the clutch drum 3 and the piston 10. The oil chamber 16 communicates with an oil passage 17 formed in the input shaft 2, and hydraulic pressure is supplied / released to the oil chamber 16 through the oil passage 17.

  A centrifugal hydraulic canceller 18 is disposed on the opposite side of the oil chamber 16 with the piston 10 in between. The centrifugal hydraulic canceller 18 has a substantially disc-shaped spring receiving portion 19 extending in the rotational radial direction, and extends from the outer peripheral end of the spring receiving portion 19 toward the disc portion 11 of the piston 10. It has an outer peripheral portion 21 that is bent outward and extends toward the outer peripheral cylindrical portion 12 of the piston 10.

  A plurality of return springs 22 are interposed between the piston 10 and the centrifugal hydraulic canceller 18 at equiangular intervals around the rotation center line C. The return spring 22 is made of a coil spring, for example. Due to the urging force of the return spring 22, the piston 10 and the centrifugal hydraulic canceller 18 are elastically urged in directions away from each other. By this urging, the centrifugal hydraulic canceller 18 abuts on the snap ring 23 attached to the input shaft 2 and the movement in the rotation center line direction is restricted.

  An annular seal 24 that seals between the outer peripheral portion 21 and the outer peripheral cylindrical portion 12 of the piston 10 is provided on the outer periphery of the outer peripheral portion 21 of the centrifugal hydraulic canceller 18. Accordingly, a canceller chamber 25 closed by the piston 10, the centrifugal hydraulic canceller 18 and the seal 24 is formed between the piston 10 and the centrifugal hydraulic canceller 18. The canceller chamber 25 communicates with an oil passage 26 formed in the input shaft 2, and hydraulic oil is supplied to the canceller chamber 25 through the oil passage 26.

  A pair of spring clamping portions 31 and 32 are provided on the outer periphery of the clutch drum 3. The spring clamping portions 31 and 32 have an annular plate shape surrounding the clutch drum 3 and are opposed to each other in the rotation center line direction. One spring clamping portion 31 passes through the cylindrical portion 6 of the clutch drum 3 and is connected to a sixth clutch plate 7F that is farthest from the disc portion 5 of the clutch drum 3. The other spring clamping portion 32 penetrates the cylindrical portion 6 in a loosely fitted state and is connected to a second clutch plate 7B that is secondly spaced from the disc portion 5. Note that the movable amount of the spring clamping portion 32 is regulated to be constant by the size of the opening through which the spring clamping portion 32 penetrates in the cylindrical portion 6.

  A plurality of springs 33 are interposed between the pair of spring clamping portions 31 and 32 at equiangular intervals around the rotation center line C. Each spring 33 is formed of a coil spring and is disposed in a compressed state between the pair of spring clamping portions 31 and 32. Therefore, the second clutch plate 7B and the sixth clutch plate 7F are always urged in the direction of separating from each other by the elastic force of each spring 33 through the pair of spring clamping portions 31 and 32. On the opposite side of the sixth clutch plate 7F from the second clutch plate 7B, a snap ring 34 is fixedly provided on the cylindrical portion 6 of the clutch drum 3, and the sixth clutch plate 7F is attached to the snap ring 34. It abuts and is further separated from the second clutch plate 7B.

  FIG. 3 is a graph showing the relationship between the oil pressure in the oil chamber 16 and the torque capacity (transmission torque capacity) of the friction clutch 1.

  In a state in which the oil pressure in the oil chamber 16 is released, the piston 10 is located at a position closest to the disc portion 5 of the clutch drum 3 as shown in FIG. At this time, the friction clutch 1 is in a released state where all the clutch plates 7 and the clutch disc 9 are not in pressure contact, and the torque capacity of the friction clutch 1 is 0 as shown in FIG. Further, as shown in FIG. 1, the second clutch plate 7B is separated from the second clutch disk 9B disposed between the third clutch plate 7C by the elastic force (biasing force) of the spring 33. . A canceller chamber 25 between the piston 10 and the centrifugal hydraulic canceller 18 is filled with hydraulic oil supplied through an oil passage 26.

  When hydraulic pressure is supplied from the oil flow path 17 to the oil chamber 16, the piston 10 moves to the clutch plate 7 side by the hydraulic pressure, and the pressing portion 13 of the piston 10 presses the first clutch plate 7A. By this pressing, the first clutch plate 7A is first pressed against the first clutch disk 9A, and the first clutch disk 9A is pressed against the second clutch plate 7B. At this time, the torque capacity of the friction clutch 1 has a magnitude corresponding to the hydraulic pressure of the first clutch disk 9 </ b> A and the oil chamber 16. Therefore, as shown in FIG. 3, the torque capacity of the friction clutch 1 increases relatively slowly as the oil pressure in the oil chamber 16 increases. Therefore, the torque capacity of the friction clutch 1 can be precisely controlled by controlling the oil pressure in the oil chamber 16, and the occurrence of shock when the friction clutch 1 is engaged can be suppressed.

  As the hydraulic pressure supplied to the oil chamber 16 increases, the pressing force applied from the piston 10 to the first clutch plate 7A increases. When the pressing force exceeds the urging force of the spring 33, the second clutch plate 7B moves. As shown in FIG. 2, the second clutch plate 7B comes into contact with the second clutch disk 9B. The subsequent torque capacity of the friction clutch 1 becomes a magnitude corresponding to the hydraulic pressures of all the clutch disks 9 and the oil chambers 16 as shown in FIG. To increase. When all the clutch plates 7 and the clutch disc 9 are brought into an engaged state, the torque capacity of the friction clutch 1 is maximized.

  In a state where the clutch drum 3 rotates integrally with the input shaft 2, centrifugal force acts on the hydraulic oil in the canceller chamber 25, and centrifugal hydraulic pressure is generated in the canceller chamber 25. The centrifugal oil pressure in the oil chamber 16 can be canceled (cancelled) by this centrifugal oil pressure. Therefore, when the hydraulic pressure in the oil chamber 16 is released from the engaged state, the piston 10 moves smoothly to the clutch drum 3 side mainly by the urging force of the return spring 22. When the hydraulic pressure supplied to the oil chamber 16 is released, the pressing force applied from the piston 10 to the first clutch plate 7A decreases, and when the pressing force falls below the urging force of the spring 33, the second clutch plate 7B. As shown in FIG. 1, the second clutch plate 7B is separated from the second clutch disk 9B. Therefore, the subsequent torque capacity of the friction clutch 1 decreases relatively gradually as the oil pressure in the oil chamber 16 increases as shown in FIG. Therefore, the torque capacity of the friction clutch 1 can be precisely controlled by controlling the oil pressure in the oil chamber 16, and the occurrence of shock when the friction clutch 1 is released can be suppressed.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, the configuration in which the second clutch plate 7B is biased by the spring 33 is taken up. However, the clutch plate 7 biased by the spring 33 is other than the first clutch plate 7A, and is at least Any clutch plate 7 disposed on one side of the one clutch disk 9 may be used. However, in order to effectively suppress the occurrence of shock when the friction clutch 1 is engaged / released, the number of clutch disks 9 arranged on the piston 10 side of the clutch plate 7 biased by the spring 33 is reduced. The number is preferably smaller than the number of clutch disks 9 arranged on the opposite side.

  As an urging member for urging the clutch plate 7, the spring 33 made of a coil spring has been taken up. However, this is merely an example, and the urging member only needs to be able to elastically urge the clutch plate 7. , Rubber or sponge may be used.

  Further, although the spring clamping portion 31 is connected to the sixth clutch plate 7F, the spring clamping portion 31 may be fixedly connected to the clutch drum 3.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 Friction clutch 7 (7A-7F) Clutch plate 9 (9A-9E) Clutch disc 10 Piston 33 Spring C Rotation center line

Claims (1)

A plurality of clutch plates arranged side by side in the rotation center line direction;
A plurality of clutch disks arranged alternately in the direction of the rotation center line with the clutch plate;
A piston that is provided so as to be movable in the direction of the rotation center line, and that moves to push the clutch plate disposed at the outermost end on one side in the direction of the rotation center line toward the other side in the direction of the rotation center line;
Except for the clutch plate disposed at the extreme end on the one side, the clutch plate disposed on the one side with respect to at least one of the clutch disks is elastically biased toward the one side. A friction clutch including a biasing member.

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