JP2016102526A - Multi-plate type frictional engagement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation of a pressing force against a stopper C-ring and restrict reduction in yield strength.SOLUTION: This invention comprises an outer drum 47; inner hubs 32R, 32L; outer frictional plates [mo]; inner frictional plates [mi]; a pressing mechanism 60 for adding a pressing force against a group M of laminated frictional plates kept at a state in which each of these frictional plates [mo][mi] is alternatively laminated to keep each of the frictional plates [mo][mi] in frictional engaged state and loosening the pressing force to release the frictional engaged state; a substantial annular pressure receiving plate 61 for receiving the group M of the laminated frictional plates; and a substantial annular stopper C-ring 62 that can be engaged with a peripheral groove 47b formed at any one of the outer drum 47 and the inner hubs 32R, 32L to support the pressure receiving plate 61 at the other side in a laminated direction under a state in which it is engaged with the peripheral groove 47b. The inner diameter and the outer diameter of a surface 61b opposing against the stopper C-ring 62 in the pressure receiving plate 61 are set to the same size over the entire circumference.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a frictional force generated by pressing a plurality of friction plates each having a relative rotation around an axis between an outer drum and an inner hub arranged radially inside and outside on the same axis. The present invention relates to a multi-plate frictional engagement device that can control rotation as a braking force.

  Conventionally, this type of multi-plate frictional engagement device includes an outer drum, an inner hub, and a substantially annular shape that are spline-fitted inside the outer drum. A plurality of outer friction plates, a plurality of substantially annular inner friction plates that are alternately stacked with the outer friction plates and are splined to the outside of the inner hub, the outer friction plates, and the inner friction plates And a frictional engagement state between the outer friction plate and the inner friction plate by applying a pressing force from one side of the lamination direction to the laminated friction plate group in a state where and are laminated alternately, A pressing mechanism that releases the frictional engagement state between the outer friction plate and the inner friction plate by loosening the pressing force; and the other side in the stacking direction of the stacked friction plate group. A substantially annular pressure passive plate that receives a group of friction plates, and a circumferential groove formed in one of the outer drum and the inner hub, and the pressure in a state of being engaged with the circumferential groove. There is a configuration that includes a substantially annular retaining C ring that supports the passive plate on the other side in the stacking direction (see, for example, Patent Document 1).

  Since the outer drum is constituted by a part of the transmission case, the one disclosed in Patent Document 1 has a structure in which only the inner hub rotates around the axis, but the outer drum also rotates around the axis. The same braking function can be exerted even with a structure in which only the outer drum or a structure in which only the outer drum rotates around the axis, and is the subject of the invention.

  In the conventional multi-plate frictional engagement device described above, the pressure passive plate supported by the retaining C ring is formed in a shape that is spline-fitted to the outer drum to which the retaining C ring is engaged. Specifically, the protrusions that are respectively fitted into the plurality of spline grooves formed on the inner peripheral portion of the outer drum are integrally provided on the outer peripheral portion of the pressure passive plate at intervals in the circumferential direction. Further, the inner peripheral portion of the pressure passive plate was formed in a circular shape when viewed in the axial direction.

  The retaining ring C is a C-shaped flat plate whose surface is along the radial direction of the outer drum. The outer peripheral edge is fitted into the inner peripheral groove of the outer drum, and the center of the ring extends from the inner peripheral groove. The portion protruding to the side is configured to receive and support the pressure passive plate. Specifically, both the inner diameter and the outer diameter have the same dimensions over the entire length in the circumferential direction (excluding both ends serving as fitting jig engaging portions) and the width dimension along the radial direction (C The shape flat plate width dimension) was set larger than the depth dimension of the inner peripheral groove of the outer drum.

Further, the friction plate adjacent to the side opposite to the retaining C ring in the pressure passive plate is constituted by an inner friction plate that is spline-fitted to the inner hub, and rotates around the axis together with the inner hub.
Therefore, although the rotational force of the inner friction plate acts on the pressure passive plate that abuts, the pressure passive plate is spline-fitted to the outer drum as described above, so that rotation around the axis is prevented, and There is no turning around.

JP 2008-308017 A (FIGS. 7 to 9)

According to the conventional multi-plate friction engagement device described above, the pressing force of the pressing mechanism on the laminated friction plate group is transmitted to the pressure passive plate via each friction plate, and further, the retaining C that supports the pressure passive plate. Acts on the ring.
Then, the pressing force from the pressure passive plate to the retaining C ring is transmitted through the contact surfaces of both.

  However, as described above, the pressure passive plate is formed with protrusions spaced apart in the circumferential direction, so that the outer diameter of the pressure passive plate is larger than the other portions at the protrusions. Along with this, the width dimension (dimension in the direction along the radial direction of the pressure passive plate) at the contact surface between the pressure passive plate and the retaining C ring is larger than the other portions only at the protrusions. Therefore, the contact area between the pressure passive plate and the retaining C-ring is larger than the other locations at the protrusions, and the pressing force acting on the retaining C-ring from the pressure passive plate is also increased due to the larger contact area. It becomes larger than the part.

  As a result, there is a large variation in the distribution of the pressing force acting on the retaining C-ring from the contact surface, and there is a possibility that a partial stress occurs in the retaining C-ring and stress concentration occurs locally. Since the stress concentration is repeated every time the pressing mechanism presses the laminated friction plate group, there is a possibility that the proof strength of the retaining C-ring is reduced.

  Accordingly, an object of the present invention is to provide a multi-plate friction engagement device that can solve the above-described problems, reduce variations in pressing force with respect to the retaining C-ring, and suppress a decrease in yield strength.

  A feature of the present invention is that an outer drum arranged radially inside and outside on the same axis, an inner hub, a plurality of substantially annular outer friction plates that are spline-fitted inside the outer drum, A state in which a plurality of substantially annular inner friction plates that are alternately stacked with outer friction plates and spline-fitted outside the inner hub, and the outer friction plates and the inner friction plates are alternately stacked. For the laminated friction plate group, the outer friction plate and the inner friction plate are brought into a friction engagement state by applying a pressing force from one side in the stacking direction, and the pressing force is loosened to reduce the pressing force. A pressing mechanism that releases the frictional engagement state between the outer friction plate and the inner friction plate, and a substantially annular shape that receives the laminated friction plate group on the other side in the lamination direction of the laminated friction plate group. The pressure passive plate is freely engageable with a circumferential groove formed in one of the outer passive drum, the outer drum, and the inner hub, and the pressure passive plate is engaged with the circumferential groove in the other direction in the stacking direction. A substantially annular retaining C-ring that is supported by the inner diameter and the outer diameter of the surface of the pressure passive plate facing the retaining C-ring are the same over the entire circumference. It is where it is set.

According to the present invention, since the inner diameter and the outer diameter of the surface facing the retaining C ring of the pressure passive plate are set to the same dimension over the entire circumference, the contact between the pressure passive plate and the retaining C ring is the same. The width dimension of the surface (the dimension in the direction along the radial direction of the pressure passive plate) is less changed over the entire length of the retaining C-ring.
Accordingly, since the contact area between the pressure passive plate and the retaining C ring is almost the same at any position in the circumferential direction, there is little variation in the distribution of the pressing force acting on the retaining C ring from the pressure passive plate. Thus, stress concentration can be prevented from occurring at the local portion of the retaining C ring.

As a result, it is possible to reduce variations in the pressing force with respect to the retaining C-ring and to suppress a decrease in yield strength.
Furthermore, the shape of the pressure passive plate can be simplified, and the cost can be reduced by reducing the manufacturing effort.

  Incidentally, such an effect is formed on the outer peripheral portion of the multi-plate friction engagement device having a structure in which the retaining C-ring is engaged with the peripheral groove formed on the inner peripheral portion of the outer drum or the inner hub. Any of the multi-plate frictional engagement devices structured to be engaged with the circumferential grooves can be similarly exhibited.

  In addition, a multi-plate friction engagement device with a structure in which only the inner hub rotates around the axis, a multi-plate friction engagement device with a structure in which the outer drum also rotates around the axis, and only the outer drum rotates around the axis. In any of the multi-plate frictional engagement devices structured as described above, the above-described effects can be exhibited in the same manner.

  In the present invention, it is preferable that the pressure passive plate is formed in a shape that allows relative rotation around the shaft core in both the outer drum and the inner hub.

As a comparative example, the above-described prior art is because the pressure passive plate prevents the rotation of the pressure passive plate by fitting the protrusion formed on the outer peripheral portion thereof into the spline groove of the outer drum. When a rotational force acts on the pressure passive plate from the inner friction plate adjacent in the axial direction, a blocking force in a direction opposite to the rotational direction acts on the protrusions of the pressure passive plate in a concentrated manner.
That is, stress concentration may occur in the vicinity of the protruding portion of the pressure passive plate, and there is a concern that shear failure or fatigue failure may occur in that portion.

According to this configuration, when a rotational force around the axis acts between the laminated friction plate group and the pressure passive plate, the pressure passive plate can rotate around the axis.
Therefore, it can be avoided that the rotation blocking force acts on the local portion of the pressure passive plate as in the conventional case.
As a result, it is possible to prevent the pressure passive plate from causing shear failure or fatigue failure by preventing excessive rotation as in the prior art.

  In the present invention, among the outer friction plate and the inner friction plate, the friction plate adjacent to the side opposite to the retaining C ring in the pressure passive plate is the outer drum and the inner hub. It is preferable that the friction plate is spline-fitted to the member with which the retaining C-ring is engaged.

According to this configuration, the pressure passive plate is located between the adjacent friction plate and the retaining C ring.
Further, the adjacent friction plate is spline-fitted to a member (corresponding to an outer drum or an inner hub, which is referred to as an attachment target member for convenience) to which a retaining C ring is engaged. In a state in which the pressing force by is applied to the laminated friction plate group, the adjacent friction plate, pressure passive plate, and retaining C-ring press against the axial center direction and are relative to the attachment target member around the axial center. There will be no rotation.

  Therefore, unlike the prior art, it is not necessary to provide the pressure passive plate with a protrusion for preventing relative rotation of the pressure passive plate with respect to the attachment target member, and the pressure passive plate can be formed in a simple shape. Become.

  Further, in the state where the pressing force by the pressing mechanism is applied to the laminated friction plate group, the adjacent friction plates, pressure passive plates, and retaining C-rings do not rotate relative to each other, so that the contact surfaces are rubbed and worn. In fact, the durability of each part can be improved.

It is a longitudinal cross-sectional view of a transmission case and a transmission case. It is a detailed longitudinal cross-sectional view of the transmission shaft provided with the turning clutch. It is a detailed longitudinal cross-sectional view of a turning clutch. It is an arrow view in IV-IV of FIG. It is a disassembled perspective view of a turning clutch. It is a disassembled perspective view of the turning clutch of another embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

The multi-plate friction engagement device can be used as a clutch device or a brake device. Here, for example, in a combine, a transmission clutch (multi-clutch) is transmitted to a transmission case 10 that transmits engine driving force to a crawler travel device. An example incorporated as 49) an example of a plate type frictional engagement device will be described.
The mission case 10 shown in FIG. 1 shows a state viewed from the front to the rear of the combine. The right and left displays described in the embodiment mean the direction on the paper. When looking forward from the combine driver's seat, the right and left do not match.

  The mission case 10 is made of aluminum die cast and has a two-part structure of a right side portion 10R and a left side portion 10L as shown in FIG. A step-shaped recess 10a is formed outside the left portion 10L of the mission case 10, and the recess is formed in the vicinity of the mating portion 10b of the mission case 10 (right and left portions 10R, 10L) (slightly on the left side of the drawing). 10a has entered.

  The continuously variable transmission 11 is arranged so as to enter the recess 10a of the mission case 10 (right side portion 10R), and the port block 11a of the continuously variable transmission 11 is placed in the recess 10a of the mission case 10 (left side portion 10L). It is connected.

  Right and left axle cases 15 are connected to the outside of the lower portion of the mission case 10 (right and left portions 10R and 10L) and extend to the right and left sides. A right or left axle 38 is supported inside each axle case 15 and is configured to be able to transmit driving force to a corresponding crawler traveling device (not shown).

Next, the structure of the transmission system (straight-ahead system) in the mission case 10 (right and left portions 10R, 10L) will be described.
As shown in the figure, an input shaft 22 from the continuously variable transmission 11 is supported on the upper portion of the transmission case 10, and transmission gears 23 and 24 are fixed to the input shaft 22 by a spline structure.

A transmission shaft 27 is supported on the transmission case 10 so as to be adjacent to the lower side of the input shaft 22. A high-speed gear 25 and a low-speed gear 26 are externally fitted to the transmission shaft 27 so as to be rotatable relative to each other. 25, the transmission gear 24 and the low-speed gear 26 are engaged with each other, and a shift member 28 is externally fitted to the transmission shaft 27 by a spline structure so as to be integrally rotatable and slidable.
The transmission gear 23 and the high-speed gear 25, the transmission gear 24 and the low-speed gear 26, and the shift member 28 constitute a sub-transmission device. By engaging the shift member 28 with the high-speed or low-speed gears 25 and 26, the input shaft The power of the gear 22 is shifted in two steps (high and low speed positions) and transmitted to the transmission shaft 27. Normally, the shift member 28 is slid to a position where it engages with the high speed gear 25, and the high speed position is set.

  A transmission shaft 29 is supported in parallel with the lower side of the transmission shaft 27 at the upper and lower intermediate portions of the transmission case 10, and a transmission gear is provided on the right side of the transmission shaft 29 (near the inner surface of the wall portion of the right portion 10R of the transmission case 10). 31 is fixed. The transmission gear 30 is fixed to the right side portion of the transmission shaft 27 (near the inner surface of the wall portion of the right portion 10R of the transmission case 10), and the transmission gears 30 and 31 are engaged.

Right and left output gears (an example of an inner hub) 32R and 32L are externally fitted to the transmission shaft 29 so as to be relatively rotatable, and right and left occlusions are placed on the right and left sides of the right and left output gears 32R and 32L. The portions 33R and 33L are externally fitted to the transmission shaft 29 by a spline structure so as to be integrally rotatable and slidable (the left occlusion portion 33L is disposed in the vicinity of the inner surface of the wall portion of the left portion 10L of the transmission case 10).
A right side clutch 34 is configured between the right output gear 32R and the right occlusion portion 33R, and a left side clutch 34 is configured between the left output gear 32L and the left occlusion portion 33L.

  A transmission gear 36 fixed to the axle 38 inside the transmission case 10 meshes with the right and left output gears 32R and 32L.

  With the above structure, the power of the input shaft 22 is transmitted to the transmission shaft 27, the transmission gears 30 and 31, the transmission shaft 29, the right and left side clutches 34 (the right and left occlusion portions 33R and 33L), and the right and left outputs. It is transmitted to the right and left crawler travel devices (not shown) via the gears 32R, 32L, the transmission gear 36, and the right and left axles 38, and the airframe advances straight.

Next, the right and left side clutches 34 will be described.
As shown in FIG. 2, spline portions 29 a are formed on the outer surfaces of the right and left side portions of the transmission shaft 29, and the right and left occlusal portions 33 </ b> R and 33 </ b> L can rotate and slide integrally with the spline portion 29 a of the transmission shaft 29. The receiving member 40 is externally fitted to the spline portion 29a of the transmission shaft 29 so as to be integrally rotatable.

  A plurality of recesses are disposed in the portions on the receiving member 40 side of the right and left occlusal portions 33R, 33L, and springs 41 are doubled inward and outward in each of the recesses of the right and left occlusal portions 33R, 33L. The right and left occlusion portions 33R and 33L are biased to the occlusal sides of the right and left output gears 32R and 32L by the receiving member 40 and the spring 41. The right and left occlusal portions 33R and 33L are engaged with the right and left output gears 32R and 32L, so that the right and left side clutches 34 are in a transmission state. Is transmitted to the right and left crawler travel devices (not shown) via the side clutch 34.

  A piston 42 is slidably disposed between the right and left output gears 32R, 32L and the transmission shaft 29, and the piston 42 is in contact with the right and left occlusion portions 33R, 33L. A spring pin 43 is inserted across the right and left occlusion portions 33R, 33L and the piston 42 so that the left occlusion portions 33R, 33L rotate as a unit.

  When hydraulic fluid is supplied between the right and left output gears 32R, 32L and the piston 42, the right and left occlusal portions 33R, 33L and the piston 42 resist the spring 41 and the right and left output gears 32R. , 32L is slid to the separation side, and the right and left side clutches 34 are disconnected. When the hydraulic oil between the right and left output gears 32R, 32L and the piston 42 is discharged, the right and left occlusion portions 33R, 33L and the piston 42 are moved by the spring 41 to the right and left output gears 32R, 32L. By sliding to the occlusal side, the right and left side clutches 34 are in a transmission state.

  The right and left occlusal portions 33R and 33L, the piston 42, and the transmission shaft 29 are integrally rotated by the spring pin 43 so as not to rotate relative to each other, and the inner peripheral portions of the right and left output gears 32R and 32L. And a rotational speed difference between the outer peripheral portion of the piston 42. A plurality of circumferential groove portions 42a are formed in portions of the outer peripheral portion of the piston 42 that are in contact with the inner surfaces of the right and left output gears 32R and 32L, and a part of the hydraulic oil is held in the groove portion 42a of the piston 42. Thus, seizure between the outer peripheral portion of the piston 42 and the inner peripheral portions of the right and left output gears 32R and 32L is prevented.

  A central portion between the right and left spline portions 29a of the transmission shaft 29 is configured to have the same diameter without a step, and a turning clutch 49, a piston 42, right and left occlusion portions 33R and 33L, which will be described later, The member 40 can be attached and assembled from either the right or left side of the transmission shaft 29.

Next, the structure of the transmission system (turning system) in the mission case 10 (right and left side portions 10R, 10L) will be described.
As shown in FIG. 1, the transmission shaft 44 is supported over the transmission case 10 (right and left portions 10R, 10L), and on the left side of the transmission shaft 44 (near the inner surface of the wall portion of the left portion 10L of the transmission case 10). A transmission gear 45 externally fitted so as to be relatively rotatable is meshed with the gear portion on the outer periphery of the left occlusion portion 33 </ b> L, and a slow turning clutch 46 is provided between the transmission shaft 44 and the transmission gear 45. . The slow swing clutch 46 is configured as a frictional multi-plate type, and is operated in a transmission state when hydraulic oil is supplied, and is operated in a shut-off state when the hydraulic oil is discharged.

A rotation clutch case (an example of an outer drum) 47 is fitted on the transmission shaft 29 so as to be relatively rotatable, and a transmission gear 48 fixed to the transmission shaft 44 and a transmission gear 47 a on the outer periphery of the rotation clutch case 47 are engaged with each other. ing. The turning clutch case 47 is configured symmetrically, and a right and left turning clutch 49 is formed between the turning clutch case 47 and the right and left output gears 32R and 32L.
The right and left swivel clutches 49 are configured as a frictional multi-plate type. When hydraulic oil is supplied, a plurality of friction plates m are brought into contact with each other to operate in a transmission state, and the hydraulic oil is discharged. The contact state is relaxed and a cut-off state is established.

  The turning clutch 49 will be described in more detail. Since the right and left turning clutches 49 are configured symmetrically, only the turning clutch 49 on one side (right side) will be described here.

  As shown in FIGS. 2 to 5, the swing clutch 49 includes a swing clutch case 47 and an output gear that are disposed so as to be relatively rotatable around the axis X of the transmission shaft 29 in a state of being externally fitted to the transmission shaft 29. 32R, and a plurality of substantially annular outer friction plates mo that are spline-fitted inside the turning clutch case 47 (see FIGS. 3 and 4), and the outer friction plates mo are alternately stacked and output gears. A plurality of substantially annular inner friction plates mi that are spline-fitted on the outer side of 32R.

  Further, the turning clutch 49 receives a pressing force from one side in the stacking direction with respect to the stacked friction plate group M in which the outer friction plate mo and the inner friction plate mi are alternately stacked in the axis X direction. By adding, the outer friction plate mo and the inner friction plate mi are put into a transmission state (friction engagement state), and the outer friction plate mo and the inner friction plate mi are turned off by loosening the pressing force. A piston (an example of a pressing mechanism) 60, a substantially annular pressure plate (corresponding to a pressure passive plate) 61 that receives the laminated friction plate group M on the other side in the lamination direction of the laminated friction plate group M, and a swing clutch case 47 is a substantially annular retaining member that is freely engageable with a circumferential groove 47b formed on the inner peripheral portion of 47 and supports the pressure plate 61 on the other side in the stacking direction while being engaged with the circumferential groove 47b. Is provided with a ring 62, a.

  As shown in FIG. 2, the turning clutch case 47 includes an inner cylindrical portion 47C that is externally fitted to the transmission shaft 29 so as to be relatively rotatable, an outer cylindrical portion 47A that is larger in diameter than the inner cylindrical portion 47C, an outer cylindrical portion 47C, An intermediate wall portion 47B extending from both cylinder portions 47A and 47C at an intermediate portion in the longitudinal direction with respect to the cylinder portion 47A is integrally provided.

The outer cylindrical portion 47A is integrally formed with the transmission gear 47a on the outer peripheral portion of the central portion in the longitudinal direction over the entire periphery. Further, a plurality of spline notches 47d opened at the end portions are provided from the longitudinal central portion of the outer cylinder portion 47A to both ends (see FIGS. 3 to 5).
The spline notches 47d are formed at equal intervals in the cylindrical circumferential direction, and the outer friction plate mo is spline fitted to the outer cylinder portion 47A by engaging the spline convex portion mot of the outer friction plate mo. be able to. That is, by the spline fitting, the outer friction plate mo is allowed to move relative to the outer cylinder portion 47A along the axis X direction, and the relative rotation around the axis X is restricted.
In addition, a circumferential groove 47b that can engage with the retaining C ring 62 is formed in the inner circumferential surface on the end side of the outer cylindrical portion 47A along the cylindrical circumferential direction.

  The middle wall portion 47B forms a hydraulic chamber 63 between the outer cylinder portion 47A and the inner cylinder portion 47C and a friction piston interposed in a sealed state (see FIG. 3).

The inner cylinder portion 47C is externally fitted to the transmission shaft 29 so as to be relatively rotatable around the axis X via a wear-reducing cylinder member.
Further, at a plurality of locations in the circumferential direction, there are formed communication holes 64 that allow the oil passage 29 b provided in the transmission shaft 29 and the hydraulic chamber 63 to communicate with each other.

The friction piston 60 is configured by integrally including a wall portion 60A along the middle wall portion 47B and a cylinder portion 60B along the inner cylinder portion 47C. The inner peripheral surface of the outer cylinder portion 47A and the inner cylinder It arrange | positions in the state closely_contact | adhered to the outer peripheral surface of the part 47C via a seal ring, respectively. By supplying pressure oil to the hydraulic chamber 63 formed between the middle wall portion 47B and the wall portion 60A to increase the internal pressure, the hydraulic chamber 63 slides along the axis X to the side away from the middle wall portion 47B.
The laminated friction plate group M can be pressed by this sliding movement.
When oil is discharged from the hydraulic chamber 63, the friction piston 60 is pushed back in response to the reaction force from the laminated friction plate group M.

As shown in FIG. 2, the output gear 32 </ b> R constitutes the swing clutch 46 with the swing clutch case 47 in addition to the side clutch 34 as described above.
A plurality of spline grooves 32a along the axis X direction are formed in the outer peripheral portion of the output gear 32R on the side of the turning clutch case 47 so as to be adjacent to each other in the circumferential direction (see FIGS. 3 and 4).
By engaging the spline protrusion mi of the inner friction plate mi with the spline groove 32a, the inner friction plate mi can be spline fitted to the output gear 32R. That is, by the spline fitting, the inner friction plate mi is allowed to move relative to the output gear 32R along the axis X direction, and the relative rotation around the axis X is restricted.

  As described above, the friction plate m includes a plurality of types of the outer friction plate mo that is spline fitted to the outer cylindrical portion 47A of the turning clutch case 47 and the inner friction plate mi that is spline fitted to the output gear 32R. (See FIGS. 3 to 5).

All are comprised with the cyclic | annular metal thin plate, and the spline convex part mot is formed in the outer friction board mot in several places of the outer peripheral part. The inner friction plate mi has spline projections mit formed at a plurality of locations on the inner periphery.
The laminated friction plate group M in which the inner friction plates mi and the outer friction plates mo are alternately arranged in the axis X direction is configured to be the outer friction plates mo at both ends in the axis X direction. It is configured.

The pressure plate 61 is set to have a thickness dimension larger than that of each friction plate m, and by having sufficient strength and rigidity, the pressing force applied from the friction piston 60 to the laminated friction plate group M is It is configured to be received stably.
Further, the shape in the axial X direction view is the same shape on both the front and back surfaces, and is set to be the same annular shape as that obtained by removing the spline convex portion mot from the outer friction plate mo. Specifically, the inner circumference and the outer circumference are concentric circles, and the ring width dimension along the radial direction is set to the same dimension over the entire circumference.

Therefore, in the pressure plate 61, the surface 61a facing the laminated friction plate group M is in contact with the adjacent outer friction plate mo on the entire surface, and the surface 61b facing the retaining C ring 62 on the opposite surface is in the circumferential groove 47b. Of the engaged retaining ring C 62, it comes into contact with the inner diameter side portion protruding from the circumferential groove 47 b toward the center of the circle.
Further, in the installed state, they are provided between the outer cylindrical portion 47A and the output gear 32R so that they can rotate relative to each other around the axis X.

As shown in FIGS. 4 and 5, the retaining C ring 62 is formed of a C-shaped metal plate that can be engaged with the circumferential groove 47 b of the outer cylindrical portion 47 </ b> A.
A convex portion 62a that can be engaged with one of a plurality of spline notches 47d formed in the outer cylinder portion 47A is provided at one location on the outer peripheral portion of the retaining C ring 62. Further, both end portions of the retaining C ring 62 are formed to be wide on the inner peripheral side, and a jig (not shown) for performing a diameter reduction operation when attaching / detaching to the circumferential groove 47b is provided in the wide portion 62b. An engagement hole 62c for engagement is formed.

  The retaining C ring 62 has a convex portion 62a engaged with one of the spline cutouts 47d and is engaged with the circumferential groove 47b. Positioning in the direction can be performed. In setting the length dimension of the retaining C ring 62 and the setting position of the convex portion 62a in the circumferential direction, the end of the retaining C ring 62 must be in the circumferential groove 47b in the above-described positioning state. It is carried out so that it may be located.

  Accordingly, the end of the retaining C ring 62 does not become cantilevered in the spline notch 47d, and is securely supported at both ends of the notch. As a result, for example, even if the pressing force from the friction piston 60 acts on the retaining C-ring 62, the pressure plate 61 can be prevented from slipping in a stable supporting state over the entire length.

  Further, since the contact surface with the pressure plate 61 has the same width over the entire length except for the wide width portion 62 b of the retaining C ring 62, the distribution of the pressing force acting on the retaining C ring 62 via the pressure plate 61. However, it tends to be uniform over the entire length, and stress concentration hardly occurs at the local portion of the retaining C ring 62.

  In addition, the position of the engagement hole 62c in the wide width portion 62b of the retaining C ring 62 is such that the retaining center C ring 62 is engaged with the circumferential groove 47b and the center of the ring further from the inner circumferential portion of the outer cylindrical portion 47A. It is set so as to be separated to the side. According to this, when the pressing force from the friction piston 60 acts on the retaining C-ring 62, even if the supporting reaction force acts on the retaining C-ring 62 from the inner peripheral wall of the circumferential groove 47b, the stress is applied. It is possible to make it difficult to concentrate around the engagement hole 62c, and it is possible to alleviate a decrease in strength of the retaining C ring 62.

The operating state of the turning clutch 49 will be described.
As the pressurized oil is supplied to the hydraulic chamber 63 through the oil passage 29b, the friction piston 60 presses the laminated friction plate group M and is supported by the pressure plate 61 and the retaining C ring 62. In the group M, adjacent friction plates m come into strong contact with each other. The frictional force generated on the contact surface makes it impossible for the adjacent friction plates m to rotate relative to each other around the axis X and the outer friction plate mo is spline-engaged, and the inner friction plate mi is connected to the spline. A transmission state in which the rotational force is transmitted between the combined output gears 32R and 32L is established.

  Further, as the pressure oil is discharged from the hydraulic chamber 63, the contact force between the adjacent friction plates m is loosened, and the adjacent friction plates m can rotate relative to each other around the axis X, and the swing clutch case 47 and the output gears 32R and 32L are in a cut-off state where the rotational force is not transmitted or a semi-transmission state where the rotational force is difficult to be transmitted.

  By switching between the transmission state, the cutoff state, and the semi-transmission state of the swing clutch 49, for example, only one of the right and left crawler traveling devices (not shown) is driven to rotate forward (or reversely driven), and the other is driven. It is possible to make a turn by stopping or reversely driving (or forwardly driving).

According to the swing clutch 49 of the present embodiment, the pressing force by the friction piston 60 can be transmitted from the pressure plate 61 to the retaining C ring 62 with little variation, and the durability of the retaining C ring 62 is improved. Improvements can be made.
Furthermore, the shape of the pressure plate 61 can be simplified, and the cost can be reduced by reducing the manufacturing effort.

  Incidentally, such an effect is formed on the outer peripheral portion of the multi-plate friction engagement device having a structure in which the retaining C-ring is engaged with the peripheral groove formed on the inner peripheral portion of the outer drum or the inner hub. Any of the multi-plate frictional engagement devices structured to be engaged with the circumferential grooves can be similarly exhibited.

  In addition, a multi-plate friction engagement device with a structure in which only the inner hub rotates around the axis, a multi-plate friction engagement device with a structure in which the outer drum also rotates around the axis, and only the outer drum rotates around the axis. In any of the multi-plate frictional engagement devices structured as described above, the above-described effects can be exhibited in the same manner.

According to this configuration, when a rotational force around the axis acts between the laminated friction plate group and the pressure passive plate, the pressure passive plate can rotate around the axis.
Therefore, it can be avoided that the rotation blocking force acts on the local portion of the pressure passive plate as in the conventional case.
As a result, it is possible to prevent the pressure passive plate from causing shear failure or fatigue failure by preventing excessive rotation as in the prior art.

According to this configuration, the pressure passive plate is located between the adjacent friction plate and the retaining C ring.
Further, the adjacent friction plate is spline-fitted to a member (corresponding to an outer drum or an inner hub, which is referred to as an attachment target member for convenience) to which a retaining C ring is engaged. In a state in which the pressing force by is applied to the laminated friction plate group, the adjacent friction plate, pressure passive plate, and retaining C-ring press against the axial center direction and are relative to the attachment target member around the axial center. There will be no rotation.

  Therefore, unlike the prior art, it is not necessary to provide the pressure passive plate with a protrusion for preventing relative rotation of the pressure passive plate with respect to the attachment target member, and the pressure passive plate can be formed in a simple shape. Become.

  Further, in the state where the pressing force by the pressing mechanism is applied to the laminated friction plate group, the adjacent friction plates, pressure passive plates, and retaining C-rings do not rotate relative to each other, so that the contact surfaces are rubbed and worn. There is also nothing and it can prevent that the durability of each component falls.

[Another embodiment]
Other embodiments will be described below.

<1> The multi-plate friction engagement device is not limited to the swing clutch 49 described in the previous embodiment, and may be configured as, for example, another clutch device or a brake device.
Further, the retaining C ring 62 is formed on the outer peripheral portions of the inner hubs 32R and 32L, in addition to the multi-plate frictional engagement device structured to engage with the circumferential groove 47b formed on the inner peripheral portion of the outer drum 47. It may be a multi-plate friction engagement device structured to engage with the circumferential groove.

Further, in addition to the multi-plate friction engagement device in which both the inner hubs 32R and 32L and the outer drum 47 rotate around the axis X, only the inner hubs 32R and 32L rotate around the axis X. A plate-type friction engagement device or a multi-plate friction engagement device having a structure in which only the outer drum 47 rotates around the axis X may be used.
The right and left multi-plate frictional engagement devices are not limited to those provided integrally, but may be configured as a single multi-plate frictional engagement device.
In addition, the shape and quantity of each component can be changed.

<2> The pressure passive plate 61 is not limited to the one described in the previous embodiment. For example, as shown in FIG. 6, a plurality of convex portions 61c for spline fitting to the outer peripheral portion (or inner peripheral portion). May be provided at intervals in the circumferential direction.
In the case of this embodiment, the convex portion 61c has a surface 61d positioned on the retaining C-ring 62 side of the pressure passive plate 61, the surface 61b facing the retaining C-ring 62 on the laminated friction plate group M side. Retired to be provided. Accordingly, the convex portion 61c and the retaining C ring 62 do not come into contact with each other, and as described in the previous embodiment, the distribution of the pressing force with respect to the retaining C ring 62 can be made uniform.

  Furthermore, since the convex portion 61c is spline-fitted, the pressure passive plate 61 can be prevented from rotating. In this case, the friction plate m adjacent to the pressure passive plate 61 is not limited to the outer friction plate mo but may be the inner friction plate mi.

  In short, the pressure passive plate 61 should just set the surface 61b which opposes the retaining C ring 62 among the pressure passive plates 61 so that an inner diameter and an outer diameter may become the same dimension over a perimeter.

  In addition, as mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry. In addition, it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

  The multi-plate frictional engagement device can be used for other agricultural machines instead of the combine.

32R output gear (an example of an inner hub)
32L output gear (example of inner hub)
47b Circumferential groove 60 Friction piston (an example of a pressing mechanism)
61 Pressure plate (equivalent to pressure passive plate)
61 b Surface facing the retaining C ring 62 retaining C ring M Laminated friction plate group m Friction plate mo Outer friction plate mi Inner friction plate X Axis core

Claims (3)

An outer drum disposed inside and outside in the radial direction on the same axis, an inner hub,
A plurality of substantially annular outer friction plates that are spline-fitted inside the outer drum;
A plurality of substantially annular inner friction plates that are alternately stacked with the outer friction plates and are spline-fitted outside the inner hub,
The outer friction plate and the inner friction plate are applied by applying a pressing force from one side in the stacking direction to the stacked friction plate group in which the outer friction plate and the inner friction plate are alternately stacked. A pressing mechanism that releases the frictional engagement state between the outer friction plate and the inner friction plate by releasing the pressing force.
A substantially annular pressure passive plate that receives the laminated friction plate group on the other side in the laminating direction of the laminated friction plate group;
A substantially circular shape that is freely engageable with a circumferential groove formed in one of the outer drum and the inner hub, and that supports the pressure passive plate on the other side in the stacking direction while being engaged with the circumferential groove. An annular retaining C-ring, and
The multi-plate type frictional engagement device in which the inner diameter and the outer diameter of the surface facing the retaining C-ring of the pressure passive plate are set to the same dimension over the entire circumference.   2. The multi-plate friction engagement device according to claim 1, wherein the pressure passive plate is formed in a shape that allows relative rotation around the shaft core in both the outer drum and the inner hub.   Of the outer friction plate and the inner friction plate, the friction plate adjacent to the side opposite to the retaining C ring in the pressure passive plate is the retaining C ring of the outer drum and the inner hub. The multi-plate friction engagement device according to claim 2, wherein the friction plate is a friction plate that is spline-fitted to a member that is engaged with each other.

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