JP2016223470A - Friction clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction clutch capable of shortening response time in engagement, and also capable of reducing variation in response.SOLUTION: A one-way valve 41 is interposed between a clutch oil passage 31 and a lubrication oil passage 32. By action of the one-way valve 41, in a state where a hydraulic pressure in the clutch oil passage 31 is higher than a hydraulic pressure in the lubrication oil passage 32, the clutch oil passage 31 and the lubrication oil passage 32 are cut off. When the hydraulic pressure in the clutch oil passage 31 drops lower than the hydraulic pressure in the lubrication oil passage 32 by a predetermined amount or greater, by the action of the one-way valve 41, the clutch oil passage 31 and the lubrication oil passage 32 communicate with each other, and an oil flows into the clutch oil passage 31 from the lubrication oil passage 32. Thereby, even when the hydraulic pressure in the clutch oil passage 31 drops, it can be suppressed that the inside of the clutch oil passage 31 is substituted with the air, and a state in which the clutch oil passage 31 is filled with the oil can be maintained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a friction clutch used in an automatic transmission or the like.

  For example, a plurality of friction clutches are used in an automatic transmission for a vehicle. In the automatic transmission, a plurality of friction clutches are selectively engaged and disengaged to switch the gear position.

  FIG. 3 is a cross-sectional view showing a configuration of a conventional friction clutch 101.

  The friction clutch 101 is engaged / released for transmission / interruption of rotation between the rotating shaft 102 and the rotating shaft 103 disposed on the same axis as the rotating shaft 102. A clutch drum 104 and a clutch hub 105 are fixed to the rotary shafts 102 and 103, respectively. A plurality of clutch plates 106 and 107 are provided between the clutch drum 104 and the clutch hub 105, respectively. The plurality of clutch plates (clutch plates) 106 are supported by the clutch drum 104 and are arranged at intervals in the rotation axis direction. The plurality of clutch plates (clutch discs) 107 are supported by the clutch hub 105 and are arranged so as to be alternately arranged with the clutch plates 106 in the rotation axis direction.

  A piston 108 is disposed inside the clutch drum 104 so as to be movable in the direction of the rotation axis. An oil chamber 109 is formed between the clutch drum 103 and the piston 108. Oil pressure (hydraulic oil) is supplied to the oil chamber 109 from a clutch oil passage 110 formed in the rotating shaft 102.

  When hydraulic pressure is supplied to the oil chamber 109, the piston 108 moves toward the clutch plates 106 and 107, and the clutch plates 106 and 107 are pressed by the piston 108. By this pressing, the clutch plates 106 and 107 are brought into pressure contact, and the friction clutch 101 is engaged. When the hydraulic pressure (clutch pressure) is released from this engaged state, the piston 108 moves to the side opposite to the clutch plates 106 and 107 due to the urging force of the return spring 111, and the piston 108 presses the clutch plates 106 and 107. Is released. As a result, the pressure contact between the clutch plates 106 and 107 is released, and the friction clutch 101 is released.

JP 2013-130249 A

  When the friction clutch 101 is switched from the engaged state to the released state, the hydraulic oil is released and hydraulic oil is released from the clutch oil passage 110, and the inside of the clutch oil passage 110 is replaced with air. Therefore, when the friction clutch 101 is switched from the released state to the engaged state, air that is a compressible fluid is expelled from the clutch oil passage 110 and the clutch oil passage 110 is filled with hydraulic oil, The oil pressure starts to rise. As a result, the completion of engagement of the friction clutch 101 is delayed by the time required for compression of the air in the clutch oil passage 110 (compression time) and the time required for filling the hydraulic oil in the clutch oil passage 110 (filling time) (response). delay).

  In addition, due to fluctuations in the amount of air present in the clutch oil passage 110, the response delay due to the compression time varies, and the time required from the start of engagement of the friction clutch to the completion of the engagement (response time) varies. There is also.

  An object of the present invention is to provide a friction clutch that can shorten the response time at the time of engagement and can reduce variations in the response.

  In order to achieve the above object, a friction clutch according to the present invention includes a plurality of clutch plates arranged side by side in the rotation axis direction, a piston provided movably in the rotation axis direction, and a clutch plate side with respect to the piston. An oil chamber that is formed on the opposite side of the cylinder and is supplied with hydraulic pressure for pressing the plurality of clutch plates against the piston, and a first oil passage that communicates with the oil chamber and through which the oil for supplying hydraulic pressure circulates. And the second oil passage through which the oil supplied by a system different from the oil flowing through the first oil passage circulates, the first oil passage and the second oil passage, and from the second oil passage A one-way valve that allows oil to flow to the first oil passage and prevents oil from flowing from the first oil passage to the second oil passage.

  According to this configuration, the plurality of clutch plates are arranged side by side in the rotation axis direction. A piston is provided on one side of the rotational axis direction with respect to the plurality of clutch plates so as to be movable in the rotational axis direction. An oil chamber is formed on one side in the rotational axis direction with respect to the piston. Oil pressure is supplied to the oil chamber through the first oil passage. The piston receives the hydraulic pressure supplied to the oil chamber, and presses the plurality of clutch plates from one side in the rotation axis direction by the hydraulic pressure. By this pressing, the clutch plates are pressed against each other and the friction clutch is engaged.

  When the hydraulic pressure (clutch pressure) in the oil chamber is released from the engaged state, the pressure on the clutch plate by the piston is released, and the friction clutch is released. As the clutch pressure decreases, the hydraulic pressure in the first oil passage decreases. A one-way valve is interposed between the first oil passage and the second oil passage. By the action of this one-way valve, the first oil passage and the second oil passage are shut off when the oil pressure in the first oil passage is higher than the oil pressure in the second oil passage. When the oil pressure in the first oil passage is lower than the oil pressure in the second oil passage by a predetermined value or more, the first oil passage and the second oil passage communicate with each other by the action of the one-way valve, and the first oil passage passes through the first oil passage. Oil flows into the oil passage. Thereby, even if the oil pressure in the first oil passage is lowered, it is possible to prevent the inside of the first oil passage from being replaced with air, and it is possible to maintain the state where the first oil passage is filled with oil.

  Therefore, when the friction clutch is switched from the released state to the engaged state, it is possible to eliminate the need for air compression in the first oil passage and filling of the oil in the first oil passage. As a result, the time required from the start of engagement of the friction clutch to the completion of engagement, that is, the response time can be shortened, and variations in the response (response time) can be reduced.

  According to the present invention, the response time when the friction clutch is engaged can be shortened, and variations in the response can be reduced.

It is sectional drawing which cut | disconnected the friction clutch which concerns on one Embodiment of this invention by the plane containing a rotating shaft line. On the other hand, it is a figure for demonstrating each part dimension of a valve. It is sectional drawing which shows the structure of the conventional friction clutch.

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

<Friction clutch>

  FIG. 1 is a cross-sectional view of a friction clutch 1 according to an embodiment of the present invention cut along a plane including a rotation axis C. FIG.

  The friction clutch 1 is incorporated in a transmission such as an automatic transmission or a continuously variable transmission, for example, to transmit / block the rotation of another rotating shaft 3 having the rotating shaft 2 and the rotating axis C in common with the rotating shaft 2. To be engaged / released.

  At one end of the rotating shaft 2, a recess 2 </ b> A is formed that is recessed from the end surface in a direction along the rotating axis C (hereinafter simply referred to as “rotating axis direction”). One end of the rotating shaft 3 is inserted into the recess 2A, and is connected to be rotatable relative to the rotating shaft 2 and immovable in the direction of the rotating axis.

  The friction clutch 1 includes a clutch drum 11 and a clutch hub 12.

  The clutch drum 11 includes a disc portion 13 and a cylindrical portion 14. The disc portion 13 is formed integrally with the rotary shaft 2 and has a substantially disc shape extending in a direction orthogonal to the rotary axis C, that is, in the radial direction of the rotation. The outer peripheral part of the disc part 13 is bent and extended to the rotating shaft 3 side (left side in the figure) in the rotating axis direction. The cylindrical portion 14 is connected to the outer peripheral portion of the disc portion 13 and has a substantially cylindrical shape extending from the outer peripheral portion toward the rotational shaft 3 in the rotational axis direction.

  A plurality of annular clutch plates (clutch plates) 15 are arranged at intervals inside the cylindrical portion 14. The outer peripheral portion of each clutch plate 15 is splined to the cylindrical portion 14.

  The clutch hub 12 is disposed on the radially inner side of the cylindrical portion 14 of the clutch drum 11. The clutch hub 12 includes a substantially cylindrical cylindrical portion 16 extending in the rotation axis direction. The cylindrical portion 16 has a smaller diameter than the cylindrical portion 14 of the clutch drum 11, and is opposed to the cylindrical portion 14 in the rotational radial direction with a space therebetween. A plurality of annular clutch plates (clutch discs) 17 are arranged between the cylindrical portions 14 and 16 so as to be arranged alternately with the clutch plates 15 in the rotation axis direction. The inner peripheral portion of each clutch plate 17 is splined to the cylindrical portion 16.

  A piston 18 is disposed on the radially inner side of the clutch drum 11. The piston 18 is provided so as to be movable in the rotational axis direction on the disc part 13 side of the clutch drum 11 with respect to the clutch plates 15 and 17. The piston 18 is integrally provided with a disc part 19, an inner peripheral part 20 and an outer peripheral part 21. The disc portion 19 has a substantially disc shape extending in the radial direction. The inner peripheral portion 20 extends from the inner peripheral end of the disc portion 19 to the clutch plates 15 and 17 side in the rotational axis direction, bends inward in the rotational radial direction, and its tip is a gap with respect to the outer peripheral surface of the rotational shaft 2. Facing each other. The outer peripheral portion 21 extends from the outer peripheral end of the disc portion 19 toward the clutch plates 15 and 17 in the rotational axis direction, bends outward in the rotational radial direction, and has its tip on the inner peripheral surface of the cylindrical portion 14 of the clutch drum 11. Opposing with a gap.

  A seal 22 is attached to the piston 18 on the surface of the clutch drum 11 on the disc part 13 side. The seal 22 is provided so as to cover the entire surface of the disc portion 19 of the piston 18 and the inner peripheral portion 20 on the disc portion 13 side. Regardless of the position of the piston 18, the inner peripheral portion 23 and the outer peripheral portion 24 of the seal 22 are always in contact with the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the outer peripheral portion of the disc portion 13, respectively. Thereby, between the rotating shaft 2 and the inner peripheral part 20 of the piston 18 and between the disc part 13 of the clutch drum 11 and the disc part 19 of the piston 18, the inner peripheral part 23 and the outer peripheral part of the seal 22, respectively. 24 is liquid-tightly sealed. An oil chamber 25 defined by the rotating shaft 2, the clutch drum 11 and the seal 22 is formed between the clutch drum 11 and the piston 18.

  The seal 22 only needs to be capable of liquid-tightly sealing between the rotary shaft 2 and the inner peripheral portion 20 of the piston 18 and between the disc portion 13 of the clutch drum 11 and the disc portion 19 of the piston 18. For example, for example, a first seal that liquid-tightly seals between the rotating shaft 2 and the inner peripheral portion 20 and a second seal that liquid-tightly seals between the disk portions 13 and 19. You may divide and comprise.

  A canceller 26 is disposed between the rotary shaft 2 and the outer peripheral portion 21 of the piston 18. The canceller 26 is externally fitted on the outer periphery of the rotary shaft 2 and is formed in a substantially annular plate shape with a midway portion in the rotational radial direction bent in a crank shape.

  A return spring 27 is interposed between the piston 18 and the canceller 26. Due to the urging force of the return spring 27, the piston 18 and the canceller 26 are elastically urged in a direction away from each other. By this urging, the canceller 26 abuts on a snap ring 28 attached to the rotation shaft 2 and movement in the rotation axis direction is restricted.

  A seal 29 that seals between the outer peripheral portion of the canceller 26 and the outer peripheral portion 21 of the piston 18 is provided on the outer peripheral portion of the canceller 26. Thus, a canceller chamber 30 defined by the piston 18, the canceller 26 and the seals 22 and 29 is formed between the piston 18 and the canceller 26.

  A clutch oil passage 31 and a lubricating oil passage 32 are formed on the rotary shaft 2. The clutch oil passage 31 and the lubricating oil passage 32 are formed independently of each other at positions away from the rotation axis, and extend in the direction of the rotation axis. Oils (operating oil and lubricating oil) are supplied to the clutch oil passage 31 and the lubricating oil passage 32 by different systems.

  The end of the clutch oil passage 31 on the rotating shaft 3 side is disposed at a position spaced from the bottom surface of the recess 2 </ b> A of the rotating shaft 2. The clutch oil passage 31 has a branch oil passage 33 that branches from the end thereof. The other end of the branch oil passage 33 is opened at the outer peripheral surface of the rotating shaft 2 between the clutch drum 11 and the piston 18. Thereby, the clutch oil passage 31 communicates with the oil chamber 25.

  In a state where the oil pressure in the oil chamber 25 is released, the piston 18 is located at a position closest to the disc portion 13 of the clutch drum 11. At this time, the clutch plates 15 and 17 are not in pressure contact with each other, the friction clutch 1 is in a released state, and transmission of rotation between the rotary shafts 2 and 3 is cut off.

  When hydraulic pressure is supplied from the clutch oil passage 31 to the oil chamber 25, the piston 18 moves toward the clutch plates 15 and 17 due to the hydraulic pressure, and the piston 18 presses the clutch plates 15 and 17. By this pressing, the clutch plates 15 and 17 are pressed against each other, the friction clutch 1 is engaged, and rotation is transmitted between the rotating shafts 2 and 3.

  When the rotary shafts 2 and 3 rotate, centrifugal oil pressure is generated in the oil chamber 25, and the piston 18 is urged toward the clutch plates 15 and 17 by this centrifugal oil pressure. A canceller chamber 30 formed on the opposite side of the oil chamber 25 across the piston 18 is filled with oil supplied from the lubricating oil passage 35. Therefore, centrifugal oil pressure is also generated in the canceller chamber 30 when the rotary shafts 2 and 3 are rotated. The centrifugal hydraulic pressure generated in the oil chamber 25 can be canceled (cancelled) by the centrifugal hydraulic pressure generated in the canceller chamber 30.

  When the hydraulic pressure in the oil chamber 25 is released from the engaged state, the urging force of the return spring 27 moves the piston 18 toward the clutch drum 11 side. At this time, the centrifugal oil pressure generated in the canceller chamber 30 cancels the centrifugal oil pressure generated in the oil chamber 25, thereby preventing the centrifugal oil pressure generated in the oil chamber 25 from obstructing the movement of the piston 18. .

  The end of the lubricating oil passage 32 on the rotating shaft 3 side is opened at the bottom surface of the recess 2 </ b> A of the rotating shaft 2. As a result, the lubricating oil passage 32 communicates with the space 34 formed between the bottom surface of the recess 2A of the rotating shaft 2 and the end surface of the rotating shaft 3 inserted into the recessed portion 2A. Filled with oil supplied from 32.

  A one-way valve 41 is interposed between the end of the clutch oil passage 31 on the rotating shaft 3 side and the space 34.

<One-way valve>

  FIG. 2 is a diagram for explaining the dimensions of each part of the one-way valve 41.

  On the other hand, the valve 41 is, for example, a ball check valve, and includes a spherical valve element 43 in the valve box 42. A circular inflow port 44 communicating with the space 34 and a circular outflow port 45 communicating with the clutch oil passage 31 are formed in the valve box 42. The outflow port 45 has an opening area larger than that of the inflow port 44, and the inflow port 44 and the outflow port 45 are connected by a valve seat surface 46 that spreads toward the outflow port 45 side.

  On the other hand, the valve 41 is closed when the valve body 43 is pressed against the inlet 44, and is opened when the valve body 43 is separated from the inlet 44.

  On the other hand, the dimensions of each part of the valve 41 are designed so that the following conditions (1) to (3) are satisfied.

(1) In a state where the friction clutch 1 is released and the rotation shaft 2 is stopped rotating, the open state of the one-way valve 41 is maintained, oil flows into the clutch oil passage 31 from the space 34, and the clutch oil passage 31. When the internal hydraulic pressure (clutch pressure) exceeds the sum of the hydraulic pressure (lubricating pressure) in the space 34 and the force required to move the valve body 43 to the inlet 44 along the valve seat surface 46, The valve 41 is closed and the clutch oil passage 31 and the space 34 are shut off.

(2) In a state where the friction clutch 1 is engaged and the rotary shafts 2 and 3 are rotating, when the clutch pressure exceeds the sum of the lubricating pressure and the centrifugal force generated in the valve body 43, the one-way valve 41 is closed. State is maintained.

(3) When the friction clutch 1 is released and the rotary shaft 2 is rotating, the hydraulic pressure remaining in the clutch oil passage 31 (clutch residual pressure) is lower than the sum of the lubricating pressure and the centrifugal force generated in the valve body 43. At this time, the open state of the one-way valve 41 is maintained.

  Conditions (1) to (3) can be represented by the following formulas (1) to (3), respectively.

^{Pl · π (Dcosθ) 2/} 4 + mgtanθ <P · π (Dcosθ) 2/4
... (1)
^{Pl · π (Dcosθ) 2/} 4 + mR (2πN / 60) 2 · tanθ
^{<P · π (Dcosθ) 2} /4 ··· (2)
^{Pl · π (Dcosθ) 2/} 4 + mR (2πN / 60) 2 · tanθ
^{> P '· π (Dcosθ)} 2/4 ··· (3)
g: Gravitational acceleration θ: Angle of the valve seat surface 46 with respect to the rotation axis direction (seat angle)
D: Diameter of the valve body 43 m: Mass of the valve body 43 R: Distance in the rotation radial direction between the rotation axis and the center of the valve body 43 N: Number of rotations of the rotation shaft 2 Pl: Lubrication pressure P: Clutch pressure P ′: Clutch residual pressure

<Effect>

  As described above, in the friction clutch 1, the plurality of clutch plates 15 and 17 are arranged side by side in the rotation axis direction. A piston 18 is provided on one side of the rotational axis direction with respect to the plurality of clutch plates 15 and 17 so as to be movable in the rotational axis direction. An oil chamber 25 is formed on one side in the rotational axis direction with respect to the piston 18. Oil pressure is supplied to the oil chamber 25 through the clutch oil passage 31. The piston 18 receives the hydraulic pressure supplied to the oil chamber 25 and presses the plurality of clutch plates 15 and 17 from one side in the rotational axis direction by the hydraulic pressure. By this pressing, the clutch plates 15 and 17 are pressed against each other, and the friction clutch 1 is engaged.

  When the hydraulic pressure (clutch pressure) in the oil chamber 25 is released from the engaged state, the pressure on the clutch plates 15 and 17 by the piston 18 is released, and the friction clutch 1 is released. As the clutch pressure decreases, the hydraulic pressure in the clutch oil passage 31 decreases. A one-way valve 41 is interposed between the clutch oil passage 31 and the lubricating oil passage 32. By the action of the one-way valve 41, the clutch oil passage 31 and the lubricating oil passage 32 are cut off when the hydraulic pressure in the clutch oil passage 31 is higher than the hydraulic pressure in the lubricating oil passage 32. When the hydraulic pressure in the clutch oil passage 31 is lower than the predetermined hydraulic pressure in the lubricating oil passage 32, the clutch oil passage 31 and the lubricating oil passage 32 communicate with each other by the action of the one-way valve 41, and the clutch from the lubricating oil passage 32 to the clutch. Oil flows into the oil passage 31. Thereby, even if the oil pressure in the clutch oil passage 31 is lowered, the inside of the clutch oil passage 31 can be suppressed from being replaced with air, and the state where the clutch oil passage 31 is filled with oil can be maintained.

  Therefore, when the friction clutch 1 is switched from the disengaged state to the engaged state, it is possible to eliminate the need to compress the air in the clutch oil passage 31 and fill the clutch oil passage 31 with oil. As a result, the time required from the start of engagement of the friction clutch 1 to the completion of engagement, that is, the response time can be shortened, and variations in the response (response time) can be reduced.

<Modification>

  While one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

  For example, as the one-way valve 41, a ball check valve including a spherical valve element 43 is taken as an example. However, a swing check valve, in which a valve element is swingably supported by an arm having a pin as a fulcrum, Other types of valves may be employed, such as a poppet valve supported so as to be capable of reciprocating linear movement, and a spring-type safety valve having a valve body and a spring that biases the valve body.

  Further, although the configuration in which the one-way valve 41 is disposed in the recess 2 </ b> A has been taken up, the position of the one-way valve 41 is not particularly limited as long as it is between the clutch oil passage 31 and the lubricating oil passage 32.

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

1 Friction clutch 15 Clutch plate 17 Clutch plate 18 Piston 25 Oil chamber 31 Clutch oil passage (first oil passage)
32 Lubricating oil passage (second oil passage)
33 Branch oil passage (first oil passage)
41 One-way valve C Rotation axis

Claims (1)

A plurality of clutch plates arranged side by side in the rotational axis direction;
A piston provided movably in the rotational axis direction;
An oil chamber that is formed on the side opposite to the clutch plate side with respect to the piston, and is supplied with hydraulic pressure for pressing the plurality of clutch plates against the piston;
A first oil passage communicating with the oil chamber and through which oil for supplying hydraulic pressure to the oil chamber flows;
A second oil passage through which oil supplied by a system different from the oil flowing through the first oil passage flows;
It is interposed between the first oil passage and the second oil passage, allows oil to flow from the second oil passage to the first oil passage, and from the first oil passage to the second oil passage. And a one-way valve for preventing the oil from flowing.

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