JP4821174B2 - Transmission clutch structure - Google Patents

Description

  The present invention relates to a clutch structure used in a transmission, and belongs to the technical field of a transmission mounted in an automobile.

  In general, an automatic transmission mounted on an automobile is configured to switch a power transmission path of a transmission gear mechanism by a selective operation of a plurality of frictional engagement devices such as a multi-plate clutch to shift to a predetermined gear stage. However, as disclosed in Patent Documents 1 and 2, for example, the clutch is configured as follows.

  That is, as shown in FIG. 13, the clutch 100 includes a drum 101 fixed to an input-side or output-side power transmission element, a hub 102 connected to the other power transmission element among the power transmission elements, A plurality of clutch plates 103... 103 are alternately splined to the drum 101 and the hub 102 one by one. The drum 101 includes a disk-shaped vertical wall 101a, and cylindrical outer peripheral walls 101b and inner peripheral walls 101c extending in the axial direction from the outer peripheral edge and the inner peripheral edge thereof.

  An annular piston 104 slidable in the axial direction is fitted between the outer peripheral wall 101 b and the inner peripheral wall 101 c of the drum 101, and a hydraulic chamber 105 is formed by the drum 101 and the piston 104. ing. The inner peripheral wall 101c is provided with a spring receiving member 107 that supports one end of a return spring 106 that urges the piston 104 to the non-fastening side. Further, in the illustrated example, the spring receiving member 107 and the piston 104 form a centrifugal balance chamber 107 a for canceling the centrifugal hydraulic pressure in the hydraulic chamber 105.

  On the other hand, in order to seal the hydraulic chamber 105, a seal portion 108 a that seals between an inner peripheral surface of the outer peripheral wall 101 b of the drum 101 and an outer peripheral edge of the piston 104 by a seal member 108, and an inner peripheral wall 101 c of the drum 101 A seal portion 109 a that seals between the outer peripheral surface and the inner peripheral edge of the piston 104 by a seal member 109 is provided. Further, in order to seal the centrifugal balance chamber 107 a, a seal portion 110 a is provided that seals between the inner peripheral edge of the piston 104 and the outer peripheral edge of the spring receiving member 107 with a seal member 110.

When the hydraulic pressure is supplied to the hydraulic chamber 105, the piston 104 moves against the return spring 106, and the plate 103 on the drum 101 side and the plate 103 on the hub 102 side are pressed against each other. Then, power is transmitted between the drum 101 and the hub 102.
Japanese Patent Laid-Open No. 2004-251310 Japanese Patent Application Laid-Open No. 2004-211801

  By the way, in recent automatic transmissions, for example, when the vehicle is idling in the D range, the clutch may be controlled to a neutral state, and may be controlled to a so-called neutral idle state that improves fuel efficiency by reducing engine load. Furthermore, if the clutch is completely neutral in this way, there is a problem that an engagement shock occurs at the time of starting. In order to avoid this, the fuel consumption can be reduced by performing slip control to make the clutch in a slightly engaged state. There is a case where both improvement and startability are compatible. In such slip control, delicate control of the clutch engagement force is performed by adjusting the hydraulic pressure supplied to the hydraulic chamber.

  However, in such slip control, the sliding resistance of the seal portion that seals the sliding portion of the piston reduces the control stability and responsiveness of the subtle clutch fastening force, resulting in accurate slip control. There is a problem of being obstructed. To deal with this, it is conceivable to increase the hydraulic pressure supplied to the hydraulic chamber in order to reduce the effect of sliding resistance when performing delicate control of the engagement force. Becomes a problem.

  Therefore, an object of the present invention is to improve the stability and responsiveness of the clutch fastening force in the fine engagement state in the clutch structure of the transmission.

  In order to solve the above problems, the present invention is configured as follows.

First, the invention according to claim 1 of the present application includes a drum disposed on a rotating shaft, a piston slidably accommodated between an outer peripheral wall and an inner peripheral wall of the drum, and the piston. A clutch structure of a transmission having a plurality of clutch plates whose fastening force is controlled by supply control of operating pressure to a hydraulic chamber at the back, wherein a sliding portion is provided on the inner and outer peripheral portions of the piston, The hydraulic chamber is defined by an outer peripheral side hydraulic chamber provided on the outer peripheral side in the radial direction of the piston back portion and an inner peripheral side hydraulic chamber provided on the inner peripheral side. Are formed by an annular concave portion formed on the inner surface of the outer peripheral side and an annular convex portion projecting on the back surface of the piston so as to be fitted into the annular concave portion, and a seal portion is provided on the sliding portion. One of the seal portions includes an inner peripheral portion of the annular convex portion and an inner peripheral surface of the annular concave portion. A seal member provided on the inner peripheral surface of the annular convex portion, and an inner peripheral surface of the annular concave portion formed so that the clutch engagement position side is smaller in diameter than the non-engagement position side in the sliding range of the piston; With this configuration, the sliding contact force is provided so that the engagement position side is smaller than the clutch non-engagement position side in the sliding range of the piston.

  The clutch plate is a lockup clutch that connects the input side and the output side of a fluid transmission device such as a torque converter in addition to a clutch for shifting, and is configured as a multi-plate type.

According to a second aspect of the present invention, in the clutch structure of the transmission according to the first aspect , a hydraulic pressure supply passage for supplying hydraulic pressure to the outer peripheral hydraulic chamber is provided in the vertical wall of the drum. In addition, the drum is characterized in that a portion where the hydraulic pressure supply passage is provided is formed of a member different from other portions.

According to a third aspect of the present invention, in the clutch structure of the transmission according to the first aspect , a centrifugal balance chamber is formed on the clutch plate side of the piston together with the piston to cancel the hydraulic pressure of the hydraulic chamber due to centrifugal force. A plate member is provided, and the piston is provided with a communication hole that communicates the outer peripheral portion of the inner peripheral hydraulic chamber and the centrifugal balance chamber.

  According to the first aspect of the present invention, in the slip control, the hydraulic pressure is controlled to be supplied to the hydraulic chamber, and the hydraulic pressure causes the piston to move from the non-engagement position side of the clutch to the engagement position side. The plate is pressed into a fine engagement state. At this time, the at least one seal portion is provided so that the sliding contact force is smaller on the engagement position side than the clutch non-engagement position side in the sliding range of the piston, so that the sliding resistance of the piston in the fine engagement state is reduced. This improves the stability and responsiveness of the fastening force. As a result, drivability at the time of slip control such as neutral idle is improved by an appropriate slip amount. In addition, since the hydraulic pressure supplied to the hydraulic chamber can be reduced by reducing the sliding resistance, fuel consumption can be improved and fastening shock can be prevented. Further, when the piston is on the non-fastening position side, a relatively large sliding contact force is ensured, so that oil leakage is prevented and fuel consumption deterioration due to energy loss of oil leakage is suppressed.

Specifically, the hydraulic chamber is defined by an outer peripheral hydraulic chamber provided on the outer peripheral side in the radial direction of the piston back portion and an inner peripheral hydraulic chamber provided on the inner peripheral side. Is formed by an annular recess formed in the outer peripheral side inner surface portion of the drum vertical wall and an annular projection projecting on the back surface of the piston so as to be fitted in the annular recess. The part is provided between the inner peripheral part of the annular convex part and the inner peripheral surface of the annular concave part . In this seal part, the seal member mounted on the inner peripheral part of the annular convex part is annular in the finely engaged state. It will slide with respect to the inner peripheral surface of the recess. At this time, since the inner peripheral surface of the annular recess is reduced in diameter on the clutch engagement position side than the non-engagement position side in the sliding range of the piston, the sliding contact force on the engagement position side is reduced, and the above-described effects are obtained.

  On the other hand, in a clutch structure in which two hydraulic chambers are provided to control such a piston, the pressure receiving area of the piston is variable, and control is performed by supplying hydraulic pressure to the outer hydraulic chamber during slip control. The hydraulic pressure may be supplied to both hydraulic chambers when fully engaged. In such a case, since the sealing force at the fastening position is reduced as described above, the amount of oil leakage from the outer peripheral side hydraulic chamber to the inner peripheral side hydraulic chamber in the finely engaged state is increased. An increase in the required amount of oil in the inner peripheral hydraulic chamber due to the stroke of the piston when shifting from the engaged state to the engaged state is compensated, and a filling delay in the inner peripheral hydraulic chamber during clutch engagement is prevented.

Incidentally, the drum may be provided with a hydraulic pressure supply passage for supplying hydraulic oil to the inner peripheral hydraulic chamber. In this case, the drum is required to have a material with good machinability in order to process the oil passage. According to the second aspect of the present invention, since the portion where the hydraulic pressure supply passage is provided is made of a member different from the other portions, this member is made of a material having good machinability to facilitate processing. Can be achieved. Furthermore, by configuring with separate members in this way, the degree of freedom of processing is improved, and thus the members and thus the drum can be made compact.

  On the other hand, in order to prevent erroneous fastening due to the centrifugal pressure at the time of non-fastening request, a centrifugal balance chamber is generally provided to cancel the hydraulic pressure. A difference in centrifugal hydraulic pressure due to a difference in the filling state of the balance chamber results in a difference in fastening force, and an influence on driving force due to a difference in fastening timing and clutch transmission force occurs. In particular, when the engine is cold at the beginning of the engine, and when the engine is running at a low speed, the supply of hydraulic fluid to the lubrication unit may not be maintained, and the centrifugal hydraulic pressure in the centrifugal balance chamber distributed from the lubricating oil passage may not be generated. In some cases, the fastening force is excessive.

In addition, as described in the first aspect , when the hydraulic chamber is divided, the oil passage filling situation for the stroke amount may be different, and in this case, the piston is pushed back from the centrifugal hydraulic pressure of the centrifugal balance chamber. The pressing force from the inner peripheral hydraulic chamber that can counteract the force does not occur and the fastening force is insufficient.

On the other hand, according to the third aspect of the present invention, in order to stabilize the clutch engagement force in the fine engagement state in which only the hydraulic pressure to the outer peripheral side hydraulic chamber is used, the inner peripheral side hydraulic chamber is extended in the radial direction. A communication hole is provided on the outer peripheral side of the inner peripheral hydraulic chamber so that the centrifugal pressure in the centrifugal balance chamber and the inner peripheral hydraulic chamber in the range is always the same. The communication holes promote each other's filling state while complementing each other with the filling state, and inevitably the hydraulic pressure on both sides of the communication hole is made uniform so that the force on the piston due to the centrifugal pressure is completely offset.

  As a result, the influence of centrifugal oil pressure is reduced, so that the accuracy of fastening force control is improved, and fastening with an appropriate slip amount and less wasteful oil pressure is realized. This contributes to improving the durability and reliability of the clutch.

  Further, since the lubricating oil supplied to the centrifugal balance chamber side is supplied to the inner peripheral side hydraulic chamber through the communication hole, the oil pressure filling state (pre-charging) of the inner peripheral side hydraulic chamber is improved, so that the fine engagement state This also improves the responsiveness when switching from the engaged state to the engaged state, and also enhances the responsiveness when starting from neutral idle control and the responsiveness at the time of shifting, reducing the lack of start feeling due to response delay and shifting shock Is done.

  As shown in FIG. 1, an automatic transmission 10 for a vehicle according to an embodiment of the present invention includes a torque converter 20 as a main component, and a front and rear (hereinafter referred to as a transmission gear mechanism) driven by the output of the converter 20. The first and second planetary gear mechanisms 30 and 40 disposed adjacent to each other) (the engine side is the front and the non-engine side is the rear), and a clutch for switching the power transmission path formed by these planetary gear mechanisms 30 and 40, It has a plurality of frictional engagement devices 51 to 55 such as a brake and a one-way clutch 56, and thereby, 1-4 speed in the D range, 1-3 speed in the S range, 1-2 speed in the L range, and in the R range The reverse speed can be obtained.

  The torque converter 20 includes a pump 22 fixed in a case 21 connected to the engine output shaft 1, and a turbine 23 that is disposed facing the pump 22 and is driven by the pump 22 via hydraulic oil. And a stator 25 interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque, and between the case 21 and the turbine 23. And a lock-up clutch 26 that directly connects the engine output shaft 1 and the turbine 23 via the case 21. The rotation of the turbine 23 is output to the planetary gear mechanisms 30 and 40 via the turbine shaft 27.

  Here, an oil pump 12 driven by the engine output shaft 1 via a case 21 of the torque converter 20 is disposed behind the torque converter 20.

  On the other hand, each of the first and second planetary gear mechanisms 30, 40 has sun gears 31, 41, a plurality of pinions 32, 32, 42, 42 that mesh with the sun gears 31, 41, and these pinions 32,. The pinion carriers 33 and 43 that support the pins 32, 42, and 42, and ring gears 34 and 44 that mesh with the pinions 32, 32, 42, and 42, respectively.

  A forward clutch 51 is provided between the turbine shaft 27 and the sun gear 31 of the first planetary gear mechanism 30. Similarly, a reverse clutch 52 is provided between the turbine shaft 27 and the sun gear 41 of the second planetary gear mechanism 40. A 3-4 clutch 53 is interposed between the turbine shaft 27 and the pinion carrier 43 of the second planetary gear mechanism 40, and a 2-4 brake 54 for fixing the sun gear 41 of the second planetary gear mechanism 40 is provided. Is provided.

  Further, the ring gear 34 of the first planetary gear mechanism 30 and the pinion carrier 43 of the second planetary gear mechanism 40 are connected, and a low reverse brake 55 and a one-way clutch 56 are connected in parallel between the ring gear 34 and the transmission case 11. The pinion carrier 33 of the first planetary gear mechanism 30 and the ring gear 44 of the second planetary gear mechanism 40 are connected to each other, and the output gear 13 is connected to them.

  The output gear 13 is meshed with a first intermediate gear 62 on an idle shaft 61 that constitutes the intermediate transmission mechanism 60, and the second intermediate gear 63 on the idle shaft 61 and an input of the differential device 70. The gear 71 is engaged with each other, and the rotation of the output gear 13 is input to the differential case 72 of the differential device 70, and the left and right axles 73 and 74 are driven via the differential device 70.

  Here, the relationship between the operating states of the frictional engagement devices 51 to 55 such as the respective clutches and brakes and the one-way clutch 56 and the gear position is summarized as shown in Table 1 below.

  By the way, among the friction fastening devices 51 to 55, at least the clutch used to achieve the forward gear, that is, the forward clutch 51 and the 3-4 clutch 53 are multi-plate clutches, and the structure thereof will be described below. . Since the forward clutch 51 and the 3-4 clutch 53 have similar configurations, only the structure of the forward clutch 51 will be described here, and the description of the structure of the 3-4 clutch 53 will be omitted.

  As shown in FIG. 2, the forward clutch 51 includes a clutch drum 511 fixed to a turbine shaft 27 rotatably supported by a transmission case 11, and a sun gear 31 of the first planetary gear mechanism 30 (see FIG. 1). ), The clutch hub 512 splined to the forward extension 31a, a plurality of drive plates 513a... 513a splined to the hub 512, and the drive plates 513a. In addition, a plurality of driven plates 513b... 513b splined to the drum 511 are accommodated in the drum 511 so as to be slidable in the axial direction. The piston 515 forming the hydraulic chamber 514 b and the turbine shaft 27 are fixed to the piston And a plate member 517 which forms a centrifugal balance chamber 516 with 515.

  The drum 511 has an annular vertical wall 511a, a cylindrical outer peripheral wall 511b, and an inner peripheral wall 511c, and the cross section of the upper and lower half portions divided by the shaft center is substantially U-shaped. An annular recess 511d formed in an annular shape is provided on the outer peripheral side and the inner surface side of the vertical wall 511a.

  The drum 511 is welded mainly by an outer peripheral member 511x constituting the outer peripheral wall 511b and a welded portion 511s at an inner peripheral side end portion of the outer peripheral member 511x, and an intermediate mainly constituting the vertical wall 511a and the inner peripheral wall 511c. The member 511y and the inner peripheral member 511z integrally formed with the turbine shaft 27 are welded at the welded portion 511t at the inner peripheral end of the intermediate member 511y. The material of the outer peripheral member 511x is JIS symbol name, SPC1, the material of the intermediate member 511y is S15C, and the material of the inner member 511z is SCM440H. The intermediate member 511y has a plurality of communication passages 511y ′... 511y ′ (only one communication passage is shown in FIG. 2) for supplying hydraulic pressure to the outer peripheral hydraulic chamber 514a in the circumferential direction and the like. These communication passages 511y ′... 511y ′ are formed in a direction perpendicular to the turbine shaft 27 so as to reach the annular recess 511d from the inner peripheral surface of the drum inner peripheral wall 511c. Further, the intermediate member 511y has a plurality of communication passages 511y ″... 511y ″ (only one communication passage is shown in FIG. 2) for supplying hydraulic pressure to the inner peripheral hydraulic chamber 511b. Evenly distributed.

  An annular convex portion 515 a that protrudes forward is provided on the outer peripheral side of the piston 515, and the annular convex portion 515 a is fitted into the annular concave portion 511 d of the drum 511. A space formed by the annular recess 511d of the drum 511 and the annular protrusion 515a of the piston 515 is defined as an outer peripheral hydraulic chamber 514a, and a space formed on the inner periphery thereof is defined as an inner peripheral hydraulic chamber 514b. Yes.

  On the other hand, the plate member 517 is a substantially plate-like member fixed to the turbine shaft 27. The piston 515 is provided with an extension portion 515b on the rear side from the outer peripheral portion of the annular convex portion 515a, and the outer peripheral edge of the plate member 517 is configured to be in sliding contact with the inner peripheral surface of the extension portion 515b. A space formed on the rear side of the piston 515 by the plate member 517 is a centrifugal balance chamber 516. The centrifugal balance chamber 516 is supplied with hydraulic oil from an oil passage 27a drilled in the turbine shaft 27 through a communication passage 27b. The piston 515 is provided with a communication hole 515c that communicates the centrifugal balance chamber 516 with the outer peripheral portion of the inner peripheral hydraulic chamber 514b.

  On the other hand, first to fourth seal portions 518a to 518d are provided in four sliding portions that come into contact with other members when the piston 515 slides. An annular first seal member 519a is attached to the front portion of the piston 515, and the first to third seal portions 518a to 518c are provided on the sliding portions of the seal member 519a. An annular second seal member 519b is attached to the outer peripheral edge of the plate member 517, and the fourth seal portion 518d is provided at the sliding portion between the seal member 519b and the piston 515. The first and second seal members 519a and 519b are rubber lip seals having lip-shaped protrusions.

First, as shown in an enlarged view in FIG. 3, the first seal portion 518a is provided between the inner peripheral portion of the piston 515 and the drum inner peripheral wall 511c, and is disposed on the front side on the inner peripheral portion of the first seal member 519a. The first lip portion 519a ₁ is provided so as to protrude from the outer periphery of the drum, and the outer peripheral surface 511c ′ of the drum inner peripheral wall 511c. The outer peripheral surface 511c ′ of the drum inner peripheral wall 511c is formed such that the rear side thereof is reduced in diameter compared to the front side in the sliding range Rs of the piston 515.

4, the second seal portion 518b is provided between the outer peripheral portion of the piston 515 and the drum outer peripheral wall 511b, and the outer peripheral side of the annular convex portion 515a of the first seal member 519a. The second lip portion 519a ₂ provided on the front side from the front and the inner peripheral surface 511b 'of the drum outer peripheral wall 511b. The inner peripheral surface 511b ′ of the drum outer peripheral wall 511b is formed such that the rear side has a larger diameter than the front side in the sliding range Rs of the piston 515.

Further, as shown in an enlarged view in FIG. 5, the third seal portion 518c is provided between the inner peripheral surface of the annular convex portion 515a of the piston 515 and the inner peripheral surface 511d 'of the annular concave portion 511d, and a third lip portion 519a ₃ provided on the front side from the inner peripheral side of the annular convex portion 515a of the sealing member 519a, is constructed out with the inner peripheral surface 511d 'of the annular recess 511d. The inner peripheral surface 511d 'of the annular recess 511d is formed so that the rear side is reduced in diameter compared to the front side.

Further, as shown in an enlarged view in FIG. 6, the fourth seal portion 518d is provided between the inner peripheral surface 515b 'of the extension portion 515b of the piston 515 and the outer peripheral portion of the plate member 517, and the second seal member A fourth lip portion 519b ₄ provided on the front side of 519b and an inner peripheral surface 515b 'of the extension portion 515b. The inner peripheral surface 515b ′ of the extension portion 515b is formed such that the rear side is reduced in diameter compared to the front side in the sliding range Rs of the piston 515.

  As shown in FIG. 2, the outer hydraulic chamber 514 a includes an oil passage 12 a provided in the oil pump housing 12 ′, an oil passage 11 a provided in the transmission case 11, and an intermediate member 511 y of the drum 511. Hydraulic pressure is supplied through communication paths 511y ′... 511y ′ provided to reach the annular recess 511d.

  Further, an oil passage 12b (not shown) provided in the oil pump housing 12 ', an oil passage 11b provided in the transmission case 11, and an intermediate member 511y of the drum 511 are provided in the inner peripheral hydraulic chamber 514b. Then, the hydraulic pressure is supplied through the communication path 511y ″ that reaches the inner peripheral hydraulic chamber 514b.

  When the hydraulic pressure is supplied to the outer peripheral hydraulic chamber 514a and the inner peripheral hydraulic chamber 514b, the piston 515 moves backward against the return spring 517a to drive the drive plates 513a ... 513a and the driven plates 513b ... 513b. And the drum 511 and the hub 512 are coupled to each other.

  The hydraulic control circuit 80 of the automatic transmission 10 includes a linear solenoid valve 81 that controls the hydraulic pressure supplied to the outer peripheral hydraulic chamber 514a and a control valve 82 that controls the hydraulic pressure supplied to the inner hydraulic chamber 514b. And are provided.

  The linear solenoid valve 81 is a known valve that changes the output pressure P1 by moving the spool 81a in the axial direction (right direction in the drawing) by the magnetic force generated in the solenoid coil when energized. The linear solenoid valve 81 is controlled as shown in FIG. In the range where the current is greater than or equal to Ia, the output pressure P1 increases in proportion to the increase in the control current. Further, when the control current is in the range of Ic or higher, the line pressure Pline supplied from the hydraulic pressure source P is output as it is, and when the control current is lower than Ia, the hydraulic pressure is not output at all. .

  In this hydraulic circuit 80, a first input line 83 connected to a hydraulic pressure source P and supplied with line pressure communicates with an input port of the linear solenoid valve 81 through an oil passage 12a to the outer peripheral hydraulic chamber 514a. One output line 84 is connected to the output port of the valve 81. A control pressure line 85 branched from the first output line 84 is connected to the control port of the control valve 82, and a second input line 86 to which the line pressure is supplied is connected to the input port of the valve 82 via the oil passage 12b. A second output line 87 communicating with the inner peripheral hydraulic chamber 514 b is connected to the output port of the valve 82.

  On the other hand, when the control current is equal to or less than Ib, the hydraulic pressure P1 is small, so the amount of movement of the spool 82a of the control valve 82 is small, and the second input line 86 and the second output line 87 do not communicate. As a result, the hydraulic pressure P2 supplied to the inner peripheral hydraulic chamber 514b becomes zero.

  When the control current becomes larger than Ib, the hydraulic pressure P1 increases and the spool 82a of the control valve 82 moves further to the right side. As a result, the second input line 86 and the second output line 87 communicate with each other. Thus, the hydraulic pressure P2 is supplied to the inner peripheral hydraulic chamber 514b. In the range where the control current is equal to or greater than Ic, the line pressure Pline supplied from the hydraulic pressure source P is output as it is.

  By the way, when the clutch is not engaged, the control current of the linear solenoid valve 81 is controlled to be smaller than Ia, and the hydraulic pressure is drained from both the outer peripheral side and inner peripheral side hydraulic chambers 514a and 514b. In this state, no hydraulic pressure is applied to the piston, but the hydraulic chambers 514a and 514b are filled with hydraulic oil (precharged state).

  Further, at the time of fine engagement by slip control, the control current of the linear solenoid valve 81 is controlled to a value between Ib and Ia, the hydraulic pressure P1 is supplied to the outer hydraulic chamber 514a, and the hydraulic pressure of the inner hydraulic chamber 514b is Drained and precharged.

  When the clutch is engaged, the control current of the linear solenoid valve 81 is controlled to be larger than Ic, the hydraulic pressure P1 is supplied to the outer hydraulic chamber 514a, and the hydraulic pressure P2 is supplied to the inner hydraulic chamber 514b. .

  On the other hand, when the engagement state of the clutch changes, the sealing force of the first to fourth seal portions 518a to 518d described above changes as follows.

That is, in the first sealing portion 518a, as shown in FIG. 8 (a), in the disengaged state, the first lip portion 519a ₁ of the first seal member 519a is pressed against the outer circumferential surface 511c of the drum wall 511c ' A sealing force F1 is ensured. When the state is switched from this state to the fine engagement state, the hydraulic pressure acting on the piston 515 is increased, and the piston 515 moves forward.

At this time, as shown in FIG. 8B, the outer peripheral surface 511c ′ of the drum inner peripheral wall 511c is reduced in diameter along the moving direction of the piston 515, that is, formed so that the interference is reduced. The pressing force by the 1 lip portion 519a ₁ is reduced, and the sealing force is reduced to a value in the range of FA to FB smaller than F1. Further, in the clutch engagement state, as shown in FIG. 8 (c), pressure P2 acts on the first lip portion 519a _1, the outer peripheral surface 511c of the drum wall 511c of the first lip portion 519a ₁ by the hydraulic P2 ' As a result, the pressing force increases to FC, and the sealing force increases to FC.

In the second sealing portion, in the disengaged state, the sealing force F2 is secured by pressing into the inner peripheral surface 511b of the second lip portion 519a ₂ of the drum outer peripheral wall 511b of the first seal member 519a.

Further, the inner peripheral surface 511 ′ of the drum outer peripheral wall 511b is enlarged along the moving direction of the piston 515, that is, formed so as to reduce the tightening margin, so that the non-fastened state is switched to the finely engaged state. In this case, the pressing force by the second lip portion 519a ₂ is reduced, and the sealing force is reduced to a value in the range of FA to FB smaller than F2. Further, in the clutch engagement state, the hydraulic pressure P1 acts on the second lip portion 519a _2, the pressing force of the inner peripheral surface 511b 'of the drum outer peripheral wall 511b of the second lip portion 519a ₂ is increased, the sealing force is the FC Will increase. Note that the oil pressure P1 acts even in the fine engagement state, but since the oil pressure P1 at this time is a small value, the action of increasing the sealing force is minute.

Further, in the third sealing portion, the disengaged state, the sealing force F3 is secured by pressing into the inner peripheral surface 511d 'of the third annular recess 511d of the lip portion 519a ₃ of the first seal member 519a.

The inner peripheral surface 511d 'of the annular recess 511d is reduced in diameter along the moving direction of the piston 515, that is, formed so as to reduce the tightening allowance, so that the non-fastened state is switched to the finely engaged state. At this time, the pressing force by the third lip portion is reduced, and the sealing force is reduced to a value in the range of FA to FB smaller than F3. Further, in the clutch engagement state, the hydraulic pressure P1 is applied to the third lip portion 519a _3, the pressing force of the inner peripheral surface 511d 'of the annular recess 511d by the third lip portion 519a ₃ increases, increasing the sealing force to the FC Will do. Note that the oil pressure P1 acts even in the fine engagement state, but since the oil pressure P1 at this time is a small value, the action of increasing the sealing force is minute.

In the fourth seal portion 518d, in the disengaged state, the sealing force F4 is ensured by the fourth lip portion 519b ₄ of the second sealing member 519b is pressed against the inner circumferential surface 515b 'of the extension portion 515b of the piston 515 The

Then, the inner peripheral surface 515b 'of the extension 515b is enlarged along the moving direction of the piston 515, that is, formed so as to reduce the tightening margin, so that the non-fastened state is switched to the finely engaged state. At this time, the pressing force by the fourth lip portion 519b ₄ is reduced, and the sealing force is reduced to a value in the range of FA to FB smaller than F4. Furthermore, increased hydraulic pressure in the hydraulic balance chamber 516 with the stroke of the rear of the piston 515, the pressing force of the inner peripheral surface 515b 'of the extension portion 515b of the fourth lip portion 519a ₄ is increased, the sealing force is the FC Will increase.

  When the characteristics of the first to fourth seal portions 518a to 518d are shown in a graph, the characteristics are as shown in FIG. 9 (setting of the present plan). According to this, relatively high sealing forces F1 to F4 are secured in the non-fastened position, and when the hydraulic pressure is increased to PA from this state, the sealing force decreases to FA, and in the fine engagement state, the hydraulic pressure is PA to PB. The sealing force is a value in the range of FA to FB smaller than F1 to F4. When the hydraulic pressure is greater than or equal to PA, the sealing force increases in proportion to the increase in the hydraulic pressure, and when the hydraulic pressure PC acting on the piston 515 is supplied when both the hydraulic pressures P1 and P2 are line pressures, The clutch is engaged with the sealing force FC.

The turbine shaft 27 corresponds to the rotating shaft in the clutch structure of the transmission according to claim 1, the drive plate 513a and the driven plate 513b also correspond to the clutch plate, and the sealing force shown in FIG. Corresponds to contact force. The first seal member 519a corresponds to the seal member in the clutch structure of transmission according to claim 1, wherein the communication path 511Y 'is equivalent to the hydraulic pressure supply passage in the clutch structure of transmission according to claim 2 To do.

  The effect of the clutch structure of the automatic transmission 10 will be described.

  That is, during the slip control, hydraulic pressure supply control is performed on the outer peripheral side hydraulic chamber 514a, and the piston 515 is moved rearward by this hydraulic pressure, and the drive plates 513a ... 513a and the driven plates 513b ... 513b are pressure-bonded. A fine engagement state is established. At this time, the first to fourth seal portions 518a to 518d are provided such that the seal force is smaller on the clutch engagement position side (rear side) than on the non-engagement position side (front side) in the sliding range Rs of the piston 515. Therefore, the sliding resistance of the piston 515 in the slip control is reduced, and the stability and responsiveness of the fastening force are improved. As a result, drivability at the time of slip control such as neutral idle is improved by an appropriate slip amount.

  Further, since the required oil pressure can be reduced by reducing the sliding resistance, fuel efficiency is improved, and a fastening shock is prevented. That is, as shown in the graph of FIG. 9, in the characteristic in which the sealing force is simply proportional to the conventional hydraulic pressure, variation due to sliding resistance must be taken into consideration, and the necessary sealing force is increased accordingly. However, by reducing the sliding resistance as in the setting of the present plan, it is not necessary to consider variations, so that the required sealing force can be reduced, and the required oil pressure is reduced accordingly. Further, since a linear solenoid instead of a duty solenoid is used for hydraulic control, variation in hydraulic accuracy of the hydraulic pressure P1 due to an increase in the amount of oil leakage in the fine engagement state is suppressed.

  Further, when the piston 515 is in the non-fastened position (front side), a relatively high sealing force is secured as shown in FIG. 9, so that oil leakage is prevented and energy loss due to oil leakage is caused. Deterioration of fuel consumption is suppressed. In the present embodiment, all of the first to fourth seal portions 518a to 518d have such a characteristic that the sealing force in the fine engagement state is reduced. However, at least one seal is selected according to the purpose. What is necessary is just to give such a characteristic to a part.

  Further, when the piston 515 is on the fastening position side, the whole piston 515 tries to move in the direction in which the sealing force is small, so that the inclination of the piston 515 at the time of slip control is suppressed, and the required stroke amount of the piston 515 is reduced. Reduced. Further, since the contact of the piston 515 with one piece is suppressed, the stability of the contact state of the drive plates 513a... 513a and the driven plates 513b. As a result, the response at the time of clutch engagement is improved.

  And since the contact state of the clutch fastening initial stage is stable, there also exists an advantage that the management of the wear characteristic which suppressed judder becomes easy.

  Next, the effects of the first to fourth seal portions 518a to 518d will be described individually. First, in the first seal portion 518a, the first seal member 519a mounted on the piston 515 is a drum in the fine engagement state. It will slide with respect to the inner peripheral wall 511c. At this time, the outer peripheral surface 511c 'of the drum inner peripheral wall 511c is reduced in diameter on the clutch engagement position side from the non-engagement position side in the sliding range of the piston 515. Will be obtained.

  Further, by configuring the first seal portion 518a provided on the inner peripheral side of the piston 515 in this way, there is an advantage that the amount of oil leakage is reduced as compared with the case where the sealing force on the outer peripheral side of the piston 515 is reduced. is there. That is, the amount of oil leakage increases in proportion to the circumference when the shape of the seal member 519a, the tightening allowance, and the supply hydraulic pressure are the same, and therefore the amount of leakage on the inner circumferential side of the piston 515 is larger than that on the outer circumferential side. small. As a result, loss of hydraulic energy due to oil leakage is suppressed, and fuel efficiency is improved. The oil leaked through the first seal portion 518a is supplied from the inner peripheral hydraulic chamber 514b to the centrifugal balance chamber 516, so that this oil can be used for clutch lubrication. The durability of the clutch is improved by promoting the lubrication of the clutch during the slip control.

  In the second seal portion 518b, the first seal member 519a attached to the piston 515 slides with respect to the drum outer peripheral wall 511b in the finely engaged state. At this time, the inner peripheral surface 511b 'of the drum outer peripheral wall 511b has a larger diameter on the clutch engagement position side than the non-engagement position side in the sliding range Rs of the piston 515. An effect is obtained.

  In addition, the sliding resistance of the piston 515 increases in proportion to the circumferential length when the shape, tightening allowance, and hydraulic pressure of the seal member 519a are the same, and thus such a seal portion 518a is provided on the outer periphery of the piston 515. The sliding resistance is effectively reduced, and a remarkable effect is obtained.

  On the other hand, in the third seal portion 518c, the first seal member 519a mounted on the inner peripheral portion of the annular convex portion 515a slides with respect to the inner peripheral surface 511d of the annular concave portion 511d in the finely engaged state. . At this time, since the inner peripheral surface 511d 'of the annular recess 511d is reduced in diameter on the clutch engagement position side from the non-engagement position side in the sliding range of the piston 515, the sealing force on the engagement position side is reduced, and the above-described effects are obtained. Is obtained.

  On the other hand, as described above, in the clutch structure in which the two hydraulic chambers 514a and 514b are provided to control the piston 515, the pressure receiving area of the piston 515 is variable, and the hydraulic pressure is supplied to the outer peripheral hydraulic chamber 514a during the slip control. If the hydraulic pressure is supplied to both hydraulic chambers 514a and 514b at the time of complete fastening, the sealing force at the fastening position is reduced as described above. The amount of oil leakage from the outer peripheral side hydraulic chamber 514a to the inner peripheral side hydraulic chamber 514b in the engaged state increases, and thereby the inner peripheral side hydraulic chamber due to the stroke of the piston 515 when shifting from the finely engaged state to the engaged state. The increase in the required amount of oil in 514b is compensated, and a delay in filling the inner peripheral hydraulic chamber 514b is prevented.

  In the fourth seal portion 514d, the second seal member 519b attached to the plate member 517 slides with respect to the inner peripheral surface 515b ′ of the extension portion 515b of the piston 515 in the finely engaged state. At this time, the inner peripheral surface 515b 'of the extension portion 515b is enlarged in diameter on the clutch engagement position side with respect to the non-engagement position side in the sliding range Rs of the second seal member 519b. It becomes small and the above-mentioned effect is obtained.

  On the other hand, the action of the centrifugal pressure generated in the centrifugal balance chamber 516 is necessary to prevent the unfastened drive plates 513a... 513a and the driven plates 513b. Therefore, at the time of fine engagement or fastening, there is no problem if the presence or absence of the centrifugal pressure in the centrifugal balance chamber 516 can be managed, and there is no problem even if the sealing force at the fourth seal portion 514d is made smaller at the fastening position than at the non-fastening position. Absent.

  Incidentally, the drum 511 is provided with oil passages 511y ′... 511y ′ for supplying hydraulic oil to the outer peripheral side hydraulic chamber 514a and the inner peripheral side hydraulic chamber 514b. Since the intermediate member 511y provided with the oil passages 511y ′... 511y ′ is a separate member, the intermediate member 511y can be made of a material having good cutting properties such as S15C, thereby facilitating the processing. The oil passage 511y ′ is provided from the inner peripheral surface of the vertical wall 511a to the outer peripheral side, and is a relatively long oil passage. On the other hand, since the intermediate member 511y is configured as a separate member, the degree of freedom of processing is improved, and a compact oil passage can be formed without using a special processing method, and the vertical wall 511a and the drum 511 can be formed. Compactness can be achieved.

  The oil passages 511y ′... 511y ′ and the oil passages 511 ″... 511y ″ are equally distributed in the circumferential direction, so that the hydraulic fluid force acting on the piston 515 when hydraulic pressure is supplied. And the inclination of the piston 515 is prevented.

  On the other hand, since the drum outer peripheral wall 511b is generally formed by press working or the like, a material having good formability such as rollability is preferable, and the portion connected to the turbine shaft 27 or the shaft 27 is a shaft. A material obtained by heat-treating a high-carbon material with high strength is preferable in order to prevent breakage due to torsion of the portion and sag of the joint. On the other hand, since the outer peripheral member 511x is SPC1 with good moldability and the inner peripheral member 511z is SCM440H, the drum 511 that satisfies all the above requirements is configured. Moreover, when joining each said member 511x-511z by beam welding etc., since the carbon amount which match | combined the members to join is not so high, it can weld favorably.

  On the other hand, the centrifugal balance chamber 516 is provided in order to prevent erroneous fastening due to the centrifugal pressure at the time of non-fastening request. However, when the fastening request including fine engagement is requested, the centrifugal balance chamber 516 is centrifuged due to a difference in the filling state of the centrifugal balance chamber 516. The difference in hydraulic pressure results in a difference in fastening force, and an influence on driving force due to a difference in fastening timing and clutch transmission force occurs. In particular, when the engine is cold at the beginning of the start, and when the engine speed is low, the supply of hydraulic oil to the lubrication unit may not be maintained, and the centrifugal hydraulic pressure in the centrifugal balance chamber 516 distributed from the lubricating oil passage 27a may not be generated. In that case, the fastening force is excessive.

  In addition, when the hydraulic chamber for controlling the piston 515 is divided as in the present embodiment, the oil passage filling state for the stroke amount of the piston 515 may be different. In that case, the centrifugal balance chamber 516 A pressing force from the inner peripheral hydraulic chamber 514b that can counter the force of pushing back the piston 515 from the centrifugal hydraulic pressure is not generated, and the fastening force is insufficient.

  On the other hand, as shown in FIG. 10, in order to stabilize the clutch engagement force in the fine engagement state using only the hydraulic pressure to the outer peripheral side hydraulic chamber 514a, the range to the inner peripheral side hydraulic chamber 514b in the radial direction is used. A communication hole 515c is provided on the outer peripheral side of the inner peripheral hydraulic chamber 514b so that the centrifugal pressure in the centrifugal balance chamber 516 and the inner peripheral hydraulic chamber 514b are always the same. The communication hole 515c complements the filling state with each other and promotes the filling state, and inevitably the hydraulic pressure on both sides of the communication hole 515c is made uniform to completely cancel the force applied to the piston 515 due to the centrifugal pressure. .

  As a result, the influence of centrifugal oil pressure is reduced, so that the accuracy of fastening force control is improved, and it is possible to engage with neutral slip and low waste hydraulic pressure, thereby reducing drivability and fuel consumption during neutral idle and slip control. This makes it possible to realize the action and contributes to improving the durability and reliability of the clutch.

  Further, since the lubricating oil supplied to the centrifugal balance chamber 516 side is supplied to the inner peripheral side hydraulic chamber 514b through the communication hole 515c, the oil pressure filling state (precharging) of the inner peripheral side hydraulic chamber 514b is improved. The responsiveness to the adjustment of the hydraulic pressure in the inner peripheral hydraulic chamber 514b is also improved, and the responsiveness when starting from the neutral idle control and the responsiveness at the time of shifting are also increased. Shock is reduced. In addition, although the influence of the contamination by lubricating oil flowing in into the inner peripheral side hydraulic chamber 514b can be considered, since the inner peripheral side hydraulic chamber 514b is not downstream of the gear or the clutch, there is no problem due to the inflow of contamination. Furthermore, the pressure balance will be lost when the centrifugal balance chamber 516 is not filled with lubricating oil, such as when it is extremely cold, but generally the neutral idle control is stopped when it is extremely cold. The impact of is small.

  In the present embodiment, lip seals are used as the seal members 519a and 519b attached to the piston 515, but ring seals may be used instead. In the first to third seal portions 518a to 518c, the ring seal is obtained by fitting a rubber member having a circular cross section into a concave portion provided annularly on the piston 515, and in the fourth seal portion 518d, a plate A similar rubber member is fitted into a recessed portion provided annularly on the periphery of the member 517.

  For example, as shown in FIG. 11, when the first seal portion 518a is configured using a ring seal 519c, the outer peripheral surface 511c 'of the drum inner peripheral wall 511c is relatively large at the clutch non-engagement position. The crimping action of the ring seal 519c is large, and a large sealing force is ensured. In the finely engaged state, since the outer peripheral surface 511c 'is reduced in diameter, the pressure-bonding action of the ring seal 519c is reduced and the sealing force is reduced.

  Further, at the time of fastening, the increased hydraulic pressure P2 ′ acts from the front of the ring seal 519c, and the hydraulic pressure P2 ′ acts so that the ring seal 519c is deformed. This deformation increases the sealing force to FC ′, and the same characteristics as those of the lip seals 519a and 519b as shown in FIG. 9 are obtained.

  On the other hand, when the automatic transmission 10 is provided with a lock-up clutch (not shown) for connecting the input side and the output side of the torque converter, and the lock-up clutch is a multi-plate type, the above-described seal portion The configuration of 518a to 518d can be applied.

  That is, when performing slip control in the lock-up clutch, control may be performed so that the fastening operation starts from a stopped state where a certain amount of hydraulic pressure is generated. In this case, the frictional state at the hydraulic point is changed from the dynamic friction state to the static friction state. Therefore, the friction coefficient becomes high and the sliding resistance increases. For this reason, the sliding resistance can be reduced by applying the configuration of the seal portion described above, so that a remarkable effect can be obtained.

  The present invention relates to a clutch structure mainly used in an automatic transmission, and is widely suitable for the automobile industry.

1 is a schematic diagram of a transmission according to an embodiment of the present invention. It is sectional drawing and hydraulic circuit diagram of the clutch structure of the transmission. It is an expanded sectional view of the 1st seal part. It is an expanded sectional view of the 2nd seal part. It is an expanded sectional view of the 3rd seal part. It is an expanded sectional view of the 4th seal part. It is a graph which shows the characteristic of the oil pressure with respect to the control current of a linear solenoid valve. It is explanatory drawing of the 1st seal | sticker part according to a clutch fastening state. It is a graph which shows the characteristic of the sealing force with respect to oil_pressure | hydraulic. It is explanatory drawing of the centrifugal hydraulic pressure which acts on a piston. It is explanatory drawing of a ring seal. It is explanatory drawing of the ring seal at the time of clutch fastening. It is explanatory drawing which shows the conventional clutch structure.

Explanation of symbols

10 automatic transmission 51 forward clutch 511 drum 511a vertical wall 511b outer peripheral wall 511b 'inner peripheral surface 511c inner peripheral wall 511c' outer peripheral surface 511d annular recess 511d 'inner peripheral surface 511y', 511y "communication passage 513a drive plate 513b driven outer plate 514a Side hydraulic chamber 514b Inner peripheral hydraulic chamber 515 Piston 515a Annular convex portion 515b Extension portion 515b 'Inner peripheral surface 515c Communication hole 516 Centrifugal balance chamber 517 Plate member 518a-518d First to fourth seal portions 519a, 519b First, first 2 seal members

Claims (3)

Fastened with a drum arranged on the rotating shaft, a piston slidably accommodated between the outer peripheral wall and inner peripheral wall of the drum, and supply control of operating pressure to the hydraulic chamber behind the piston A clutch structure of a transmission having a plurality of clutch plates whose force is controlled, wherein a sliding portion is provided on an inner and outer peripheral portion of the piston,
The hydraulic chamber is defined by an outer peripheral side hydraulic chamber provided on the outer peripheral side in the radial direction of the piston back portion and an inner peripheral side hydraulic chamber provided on the inner peripheral side. And is formed by an annular recess formed on the inner surface of the outer peripheral side, and an annular projection projecting on the back of the piston so as to fit into the annular recess,
A seal portion is provided on the sliding portion ;
One of the seal portions is provided between an inner peripheral portion of the annular convex portion and an inner peripheral surface of the annular concave portion, and a sliding member mounted on the inner peripheral surface of the annular convex portion and a piston slide And the inner surface of the annular recess formed so that the clutch engagement position side is smaller in diameter than the non-engagement position side, so that the sliding contact force is greater than the clutch non-engagement position side in the sliding range of the piston. A clutch structure for a transmission, wherein the side is provided to be small. In the clutch structure of the transmission according to claim 1,
The vertical wall of the drum is provided with a hydraulic pressure supply passage for supplying hydraulic pressure to the outer peripheral hydraulic chamber, and the drum is a member different from the other portions in which the hydraulic pressure supply passage is provided. A clutch structure of a transmission characterized by being configured . In the clutch structure of the transmission according to claim 1,
On the clutch plate side of the piston, a plate member is formed that forms a centrifugal balance chamber together with the piston to cancel the hydraulic pressure of the hydraulic chamber due to centrifugal force,
A clutch structure for a transmission , wherein the piston is provided with a communication hole for communicating an outer peripheral portion of an inner peripheral hydraulic chamber and a centrifugal balance chamber .

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