JP6672029B2 - Friction engagement device - Google Patents

Description

  The present invention relates to a friction engagement device that transmits rotation of an input member to an output member by friction engagement.

  Conventionally, as in a multi-plate clutch used in a transmission, an input member, a first plate that rotates integrally with the input member, a second plate that frictionally engages with the first plate, and an integral part of the second plate 2. Description of the Related Art There is known a friction engagement device that includes an output member that rotates automatically, and that transmits rotation of an input member to an output member by frictionally engaging a first plate and a second plate.

  As this kind of friction engagement device, there is a configuration in which plates are brought into contact with each other and frictionally engaged with each other by a pressing force from a piston movable in an axial direction. The position of such a piston is determined by a return spring disposed between the housing of the friction engagement device and the piston, and a hydraulic pressure supplied to an oil chamber formed between the housing and the piston. What is changed is known (for example, refer to Patent Document 1).

JP-A-2005-190526

  By the way, the plate which is a friction engagement member engages by friction. Therefore, if the device is used for a certain period of time, abrasion occurs on the surfaces in contact with each other, and the thickness in the axial direction gradually decreases.

  In this way, when the thickness of the plate in the axial direction is reduced, a return spring for returning the piston to a predetermined position is provided on the housing, as in the friction engagement device described in Patent Document 1. In the case of a configuration in which the piston is fixed, the stroke of the piston required until a pressing force is applied from the piston to the plate increases. As a result, there is a problem that the responsiveness of the friction engagement device is reduced.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a friction engagement device in which responsiveness does not easily decrease even when the friction engagement member is worn.

In order to achieve the above object, a friction engagement device according to the present invention includes an input member (I) that rotates by receiving a driving force from a driving source, and a first friction that rotates integrally with the input member (I). An engagement member (15), a second friction engagement member (16) arranged to overlap the first friction engagement member (15) in the axial direction, and an integral part of the second friction engagement member. An output member (O) that rotates and outputs the rotation, and is movable in the axial direction, and the other member is one of the first friction engagement member (15) and the second friction engagement member (16). A piston (17) for applying a pressing force in a direction approaching the above, an urging member (21) for urging the piston (17) to one side in the axial direction, and a housing (21) in which the piston (17) is disposed. 10), and an oil chamber (20) is provided between the piston (17) and the housing (10). Is formed, and the piston (17) is a friction engagement device (1) that is pressed to the other side in the axial direction according to the hydraulic pressure supplied to the oil chamber (20), and is movable in the axial direction. The piston (17) is disposed between the first frictional engagement member (15) and the second frictional engagement member (16), and applies the pressing force from the piston (17) to the first frictional engagement member. A thrust bearing (18) is added to one of the friction engagement member (15) and the second friction engagement member (16), and the urging member (21) includes the thrust bearing (18) and the piston (17). ) , One end of the urging member (21) is fixed to the piston (17), and the other end of the urging member (21) is fixed to the thrust bearing (18). It is characterized by being.

  As described above, in the friction engagement device of the present invention, since the urging member is disposed between the piston and the thrust bearing, the hydraulic pressure supplied to the oil chamber is more than the urging force of the urging member. In a state where the frictional engagement member is not transmitted to the frictional engagement member, the distance between the piston and the thrust bearing can be increased regardless of the state of wear of the frictional engagement member. It is maintained at a distance corresponding to the natural length of the member.

  Further, in a normal state, since the oil chamber is filled with the working oil, a force is applied to the piston, the urging member and the thrust bearing as a whole in a direction approaching the friction engagement member side. Thus, even when the oil pressure supplied to the oil chamber is sufficiently smaller than the urging force of the urging member, the thrust bearing is kept on the frictional engagement member regardless of the state of wear of the frictional engagement member. The state of almost contact is maintained.

Therefore, in the friction engagement device of the present invention, regardless of the state of wear of the friction engagement member, the piston stroke required until the pressing force is applied from the piston to the friction engagement member is maintained at a constant distance. You.
One end of the biasing member is secured to the piston, the other end of the biasing member, are fixed to the thrust bare-rings, the natural length by remote away distances biasing member between the piston and the thrust bearing Can be prevented.
Therefore, according to the friction engagement device of the present invention, even if the friction engagement member is worn, the responsiveness does not easily decrease.

FIG. 2 is a cross-sectional view illustrating a configuration of the friction engagement device according to the embodiment. FIG. 2B is an enlarged cross-sectional view illustrating a main part when the friction engagement device of FIG. 1 has not been worn, FIG. 2A illustrates a disengaged state, and FIG. 2B illustrates an engaged state. FIG. 3B is an enlarged cross-sectional view illustrating a main part when the frictional engagement device of FIG. 1 has worn out, in which FIG. 3A shows a disengaged state and FIG.

  Hereinafter, a friction engagement device according to the present embodiment will be described with reference to the drawings. This embodiment is an embodiment in which a friction engagement device is used as a driving force transmission device for a vehicle or the like. However, the friction engagement device of the present invention can be mounted on other mechanisms such as a driving force transmission device for other vehicles such as ships, and for unmanned vehicles.

  First, a configuration of a friction engagement device 1 which is a so-called wet-type multi-plate clutch will be described with reference to FIGS.

  As shown in FIG. 1, the friction engagement device 1 is configured as a cylindrical device. An input shaft I (input member) to which a driving force from a driving source of the vehicle is transmitted is inserted from one end side (right side in FIG. 1) of the opening of the friction engagement device 1. On the other hand, an output shaft O (output member) for transmitting the driving force transmitted via the friction engagement device 1 to the driving wheels of the vehicle is inserted from the other end (the left side in FIG. 1).

  The cylindrical friction engagement device 1 is a case 10 (housing) that forms an outer peripheral surface and an end surface, and is disposed inside the case 10, forms a part of an inner peripheral surface, and is connected to the input shaft I. It has one clutch hub 11 and a second clutch hub 12 which is arranged coaxially with the first clutch hub 11 inside the case 10, forms another part of the inner peripheral surface, and is connected to the output shaft O. .

  The case 10 has a cylindrical outer peripheral side wall 10a, an end surface 10b provided on the other end side of the outer peripheral side wall 10a, an opening provided in the center, and one axial side from the opening of the end surface 10b. And a cylindrical inner peripheral side wall portion 10c that extends.

  The first clutch hub 11 includes a cylindrical first boss 11 a that forms a part of the inner peripheral surface of the friction engagement device 1, and a radially outward side (the outer peripheral side of the case 10) from the first boss 11 a. ), And a first guide portion 11c extending from the end of the first annular portion 11b opposite to the first boss 11a to the other axial end. ing.

  The second clutch hub 12 has a cylindrical second boss portion 12a forming another part of the inner peripheral surface of the friction engagement device 1, and an annular shape extending radially outward from the second boss portion 12a. Of the second annular portion 12b, and a second guide portion 12c extending to one axial side from an end of the second annular portion 12b opposite to the second boss portion 12a.

  The first boss portion 11a of the first clutch hub 11 includes a cylindrical small diameter portion 11a1 and a cylindrical large diameter portion 11a2 which is coaxial with the small diameter portion 11a1 and has a larger diameter than the small diameter portion 11a1. .

  The distal end of the input shaft I is inserted into the cylindrical small diameter portion 11a1 from one end side. The first clutch hub 11 and the input shaft I are spline-connected at a tip end of the input shaft I and a part of the inner peripheral surface of the small diameter portion 11a1.

  The second boss portion 12a of the second clutch hub 12 is inserted into the cylindrical large diameter portion 11a2 from the other end. A first ball bearing 13 is disposed between the inner peripheral surface of the large diameter portion 11a2 of the first clutch hub 11 and one end of the outer peripheral surface of the second boss portion 12a of the second clutch hub 12. . Therefore, the first clutch hub 11 is relatively rotatable integrally with the input shaft I with respect to the second clutch hub 12 (that is, the output shaft O).

  The second boss portion 12a of the second clutch hub 12 is formed in a tubular shape, and the tip of the output shaft O is inserted from the other end. The second clutch hub 12 and the output shaft O are spline-connected at a tip end of the output shaft O and a part of the inner peripheral surface of the second boss 12a.

  A ball bearing 14 is disposed between the other end of the outer peripheral surface of the second boss 12 a of the second clutch hub 12 and the inner peripheral surface of the inner peripheral side wall 10 c of the case 10. Therefore, the second clutch hub 12 can rotate integrally with the output shaft O with respect to the case 10.

  The first guide portion 11c of the first clutch hub 11 is formed in a tubular shape. A plurality of first groove portions 11c1 extending in the axial direction are formed on the inner peripheral surface side of the first guide portion 11c. A plurality of annular outer plates 15 (first friction engagement members) are arranged on the inner peripheral surface side of the first guide portion 11c. The plate at the other end of the outer plate 15 is an end plate 15a that comes into contact with a thrust bearing 18 described later.

  A plurality of claw portions are formed on the outer peripheral side of the outer plate 15 so as to correspond to the first groove portions 11c1. Therefore, each outer plate 15 is movable in the axial direction on the inner peripheral surface side of the first guide portion 11c. On the other hand, the outer plate 15 rotates integrally with the first guide portion 11c (that is, the first clutch hub 11 and the input shaft I) in the circumferential direction.

  The second guide portion 12c of the second clutch hub 12 is formed in a cylindrical shape, and the first guide portion 11c of the first clutch hub 11 and the outer plate 15 disposed on the inner peripheral side of the first guide portion 11c. It is arranged on the inner peripheral side. A plurality of second groove portions 12c1 extending in the axial direction are formed on the outer peripheral surface side of the second guide portion 12c. A plurality of annular inner plates 16 (second friction engagement members) are arranged on the outer peripheral surface side of the second guide portion 12c.

  A plurality of claw portions are formed on the inner peripheral side of the inner plate 16 so as to correspond to the second groove portions 12c1. Therefore, each inner plate 16 is movable in the axial direction on the outer peripheral surface side of the second guide portion 12c. On the other hand, the inner plate 16 rotates integrally with the second guide portion 12c (that is, the second clutch hub 12 and the output shaft O) in the circumferential direction.

  The plurality of outer plates 15 and the plurality of inner plates 16 are arranged so as to alternately overlap in the axial direction. The outer plate 15 and the inner plate 16 frictionally engage with each other when pressed by the piston 17 toward one axial side. In the frictionally engaged state, since the outer plate 15 and the inner plate 16 rotate integrally, the rotation of the input shaft I causes the rotation of the first clutch hub 11, the outer plate 15, the inner plate 16, and the second clutch hub. The output 12 is transmitted to the output shaft O.

  In the friction engagement device 1, the outermost plate 15 (end plate 15a) on the other end side is disposed closer to the piston 17 than the innermost plate 16 on the other end side. However, the inner plate 16 at the other end may be disposed closer to the piston 17 than the outer plate 15 at the other end. In that case, the inner plate 16 at the other end that contacts the thrust bearing 18 may be configured as an end plate.

  Further, the friction engagement device 1 has an annular piston 17 disposed on the other end side of the outer plate 15 and the inner plate 16 inside the case 10, and is disposed between the piston 17 and the outer plate 15 and the inner plate 16. And a thrust bearing 18 provided.

  The outer peripheral surface of the piston 17 is slidable with the inner peripheral surface of the outer peripheral side wall portion 10a of the case 10. On the other hand, the inner peripheral surface of the piston 17 is slidable with the outer peripheral surface of the inner peripheral side wall portion 10c of the case 10. A groove 17a provided on the outer peripheral surface and the inner peripheral surface of the piston 17 has a liquid-tight seal O between the piston 17 and the outer peripheral side wall portion 10a or between the piston 17 and the inner peripheral side wall portion 10c. The ring 19 is arranged; Thereby, an oil chamber 20 is formed between the piston 17 and the case 10.

  Hydraulic oil is supplied to the oil chamber 20 from an oil pressure control circuit HC including an oil pump and a plurality of valves via an oil passage. The oil pressure of the working oil supplied from the oil pressure control circuit HC is detected by an oil pressure sensor HS. The piston 17 moves to one end in the axial direction as the volume of the oil chamber 20 increases.

  A protrusion 17 b is provided on a surface on one end side of the piston 17. The protrusion 17b contacts a protrusion receiving portion (not shown) provided on the inner peripheral side wall portion 10c of the case 10. Thereby, rotation of the piston 17 around the axis is suppressed.

  A bearing support 17c is provided at a position on one end of the piston 17 facing the end plate 15a. A thrust bearing 18 is arranged between the bearing support 17c and the end plate 15a so as to be movable in the axial direction.

  A plurality of thrust bearings 18 are disposed between the first race 18a, the second race 18b disposed opposite to the first race 18a, and the first race 18a and the second race 18b. It is composed of a cylindrical roller 18c and a retainer 18d for maintaining the interval between the rollers 18c.

  The first race 18a is in contact with the bearing support 17c of the piston 17 on the surface opposite to the roller 18c (the surface on the other end). The second race 18b is in contact with an end plate 15a disposed on the other end side of the outer plate 15 on the surface (one end surface) opposite to the roller 18c.

  Therefore, when the piston 17 moves to one end side, the pressing force from the piston 17 to the end plate 15a is transmitted via the thrust bearing 18.

  In the thrust bearing 18, a bearing-side receiving portion 18e extends from the first race 18a toward the radially inward side. A piston-side receiving portion 17d is formed at a position on the one end side of the piston 17 radially inward of the bearing supporting portion 17c so as to face the bearing-side receiving portion 18e. A return spring 21 (biasing member) is arranged between the bearing-side receiving portion 18e and the piston-side receiving portion 17d.

  The piston 17 is urged by the return spring 21 in the direction of reducing the volume of the oil chamber 20 (that is, the other end in the axial direction).

  Therefore, the piston 17 moves in the axial direction according to the hydraulic pressure supplied to the oil chamber 20 and the urging force of the return spring 21.

  In the friction engagement device 1, a coil spring is used as an urging member for urging the piston 17. However, the biasing member is not limited to the coil spring. For example, rubber or the like may be used in addition to a disc spring or a wave spring.

  In addition, in the friction engagement device 1, one end of the return spring 21 is connected to the bearing-side receiving portion to prevent the distance between the piston 17 and the thrust bearing 18 from being larger than the natural length of the return spring 21. 18e, and the other end is fixed to a piston side receiving portion 17d. However, the return spring 21 does not necessarily have to be fixed to the bearing-side receiving portion 18e or the piston-side receiving portion 17d.

  Next, the frictional engagement between the outer plate 15 and the inner plate 16 will be described with reference to FIGS.

  As shown in FIG. 2A, a state in which sufficient hydraulic oil is not supplied from the hydraulic control circuit HC to the oil chamber 20 (that is, the hydraulic pressure supplied to the oil chamber 20 is sufficiently smaller than the urging force of the return spring 21). In the state (state), the piston 17 returns to a position where the urging force of the return spring 21 and the hydraulic pressure supplied to the oil chamber 20 are balanced.

  As a result, the pressing force is not applied to the outer plate 15 and the inner plate 16, so that the outer plate 15 and the inner plate 16 are separated from each other (disengaged state). As a result, the rotation of the input shaft I is not transmitted to the inner plate 16, the second clutch hub 12, and the output shaft O via the first clutch hub 11 and the outer plate 15.

  On the other hand, as shown in FIG. 2B, a state where sufficient hydraulic oil is supplied from the hydraulic control circuit HC to the oil chamber 20 (that is, the hydraulic pressure supplied to the oil chamber 20 is more than the urging force of the return spring 21) In this state, the piston 17 moves to one end side against the urging force of the return spring 21.

  As a result, the pressing force is applied to the outer plate 15 and the inner plate 16, so that the outer plate 15 and the inner plate 16 frictionally engage with each other (engagement state). As a result, the rotation of the input shaft I is transmitted to the inner plate 16, the second clutch hub 12, and the output shaft O via the first clutch hub 11 and the outer plate 15.

  By the way, the outer plate 15 and the inner plate 16 are engaged by friction. Therefore, if the device is used for a certain period of time, abrasion occurs on the surfaces in contact with each other, and the thickness in the axial direction gradually decreases.

  In this way, when the thickness of the outer plate 15 or the inner plate 16 in the axial direction is reduced, a return spring 21 for returning the piston to a predetermined position is provided on the case 10 as in a conventional friction engagement device. In the case of a configuration in which the piston 17 is fixed, the stroke of the piston 17 required until the pressing force is applied from the piston 17 to the outer plate 15 and the inner plate 16 increases. As a result, the conventional frictional engagement device has a problem in that the response is reduced.

  Therefore, the friction engagement device 1 is movable in the axial direction, is disposed between the piston 17 and the outer plate 15, and applies a pressing force from the piston 17 to the outer plate 15 (specifically, a plurality of outer plates 15). The thrust bearing 18 is provided between the thrust bearing 18 and the piston 17.

  Therefore, as shown in FIG. 3A, in the friction engagement device 1, even if the outer plate 15 and the inner plate 16 are worn, the hydraulic pressure supplied to the oil chamber 20 is more than the urging force of the return spring 21. In a small state (that is, a disengaged state), the distance between the piston 17 and the thrust bearing 18 is maintained at a distance corresponding to the natural length of the return spring 21.

  Specifically, in a state in which abrasion has occurred (the state in FIG. 3) and a state in which abrasion has not occurred (the state in FIG. 2), one end of the end face portion 10b of the case 10 from the other end of the piston 17 Comparing the distances to the surface (x1 in FIG. 2A and x3 in FIG. 3A), the distance in the state where the wear has occurred (the distance x3 in FIG. 3A) is the distance in the state where the wear has not occurred (the distance in FIG. x1).

  However, when the distance (x2 in FIG. 2A and x4 in FIG. 3A) between the one end surface of the bearing support portion 17c of the piston 17 and the other end surface of the first race 18a of the thrust bearing 18 is compared, wear occurs. The distance in the retracted state (distance x4 in FIG. 3A) and the distance in the state where no wear occurs (x2 in FIG. 2A) are maintained at a distance corresponding to the natural length of the return spring 21 and become the same distance. I have.

  Therefore, in the friction engagement device 1, the distance until the piston 17 starts transmitting the pressing force to the thrust bearing 18 is constant regardless of the state of wear of the outer plate 15 and the inner plate 16.

  Further, in the friction engagement device 1, the oil chamber is filled with the operating oil in the normal state, so that the piston 17, the return spring 21 and the thrust bearing 18 are disposed on the outer plate 15 and the inner plate 16 side as a whole. A force in the approaching direction is applied.

  Thus, in the friction engagement device 1, even when the outer plate 15 and the inner plate 16 are worn (the state of FIG. 3A), the hydraulic pressure supplied to the oil chamber 20 is more than the urging force of the return spring 21. In a small state (i.e., an engaged state), the thrust bearing 18 is maintained in a state in which it is almost in contact with the end plate 15a, similarly to a state in which wear does not occur (the state in FIG. 2A).

  Therefore, in the friction engagement device 1, the distance until the thrust bearing 18 starts transmitting the pressing force to the end plate 15a is almost “0” regardless of the state of wear of the outer plate 15 and the inner plate 16. Will be maintained.

  Therefore, in the friction engagement device 1, regardless of the state of wear of the outer plate 15 and the inner plate 16, a pressing force is applied from the piston 17 to the outer plate 15 and the inner plate 16 via the thrust bearing 18 and the end plate 15a. The stroke of the piston 17 (moving distance from the state of FIG. 2A to the state of FIG. 2B and moving distance from the state of FIG. 3A to the state of FIG. 3B) required until it is added is a fixed distance. (Distance x2, distance x4).

  Therefore, according to the friction engagement device 1, even if the outer plate 15 and the inner plate 16 are worn, the responsiveness does not easily decrease.

DESCRIPTION OF SYMBOLS 1 ... frictional engagement device, 10 ... case (housing), 10a ... outer peripheral side wall part, 10b ... end surface part, 10c ... inner peripheral side wall part, 11 ... 1st clutch hub, 11a ... 1st boss part, 11a1 ... small diameter Part, 11a2 large diameter part, 11b first annular part, 11c first guide part, 11c1 first groove part, 12 second clutch hub, 12a second boss part, 12b second annular part, 12c ... second guide portion, 12c1 ... second groove portion, 13 ... first ball bearing, 14 ... second ball bearing, 15 ... outer plate (first friction engagement member), 15a ... end plate, 16 ... inner plate (first 17: piston, 17a: groove, 17b: projection, 17c: bearing support, 17d: piston side receiving part, 18: thrust bearing, 18a: first race, 18b: second race 18c: roller, 18d: retainer, 18e: bearing side receiving portion, 19: O-ring, 20: oil chamber, 21: return spring (biasing member), HC: hydraulic control circuit, HS: hydraulic sensor, I: input shaft (input member), O: output shaft (output member).

Claims (1)

An input member to which a driving force from a driving source is transmitted to rotate;
A first friction engagement member that rotates integrally with the input member;
A second frictional engagement member disposed so as to axially overlap the first frictional engagement member;
An output member that rotates integrally with the second friction engagement member and outputs rotation;
A piston that is movable in an axial direction and applies a pressing force to one of the first friction engagement member and the second friction engagement member in a direction approaching the other;
An urging member for urging the piston to one side in the axial direction;
A housing in which the piston is disposed,
An oil chamber is formed between the piston and the housing,
The piston is a friction engagement device that is pressed to the other side in the axial direction according to the hydraulic pressure supplied to the oil chamber,
The piston is freely movable in the axial direction, is disposed between the piston and the first frictional engagement member and the second frictional engagement member, and applies the pressing force from the piston to the first frictional engagement member and the first frictional engagement member. A thrust bearing added to one of the second friction engagement members,
The urging member is disposed between the thrust bearing and the piston ,
One end of the biasing member is secured to the piston, the other end of the biasing member, the frictional engagement device, characterized in that fixed to the thrust bets bearing.