JPH0453461Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an improvement of a wet hydraulic clutch.

Prior Art Hydraulic clutches are usually provided with a pressing member for pressing the clutch disk, and the stroke of the pressing member driven by the clutch hydraulic pressure and the clutch engagement operation time increase as the clutch disk wears. In order to prevent this, it is desirable to have the pressing member standby at a position close to the clutch disc. On the other hand, a proximity control valve that is switched and activated in the state immediately before the pressing member presses the clutch disk is provided in the pressing member in the clutch case, and the clutch hydraulic pressure acting on the pressing member is discharged by the operation of the proximity control valve. A type of hydraulic clutch has been proposed in which the forward movement of a pressing member is stopped by applying pressure. For example, there is a hydraulic clutch described in Japanese Patent Application No. 1983-78845 filed by the present applicant.

Problems to be Solved by the Invention By the way, the conventional type of hydraulic clutch as described above is provided with a proximity control valve that operates when the clutch disk is approached, and the proximity control valve acts on the pressing member of the clutch. Hydraulic pressure is discharged to the outside through a discharge oil path. This discharge oil passage is formed by, for example, a cylindrical projection protruding from a fixed transmission case, a clutch case fitted to the cylindrical projection so as to be relatively rotatable, and a clutch case fitted slidably within the clutch case. are formed through the respective pressing members. For this reason, in order to configure the discharge oil passage, for example, the width of the discharge oil passage is installed on the outer circumferential surface of the cylindrical projection, and a sealing member is installed to seal this discharge oil passage from other oil passages. The width dimension of the hydraulic clutch is required in the width direction, resulting in an inconvenience that the axial dimension of the hydraulic clutch becomes large. Such an inconvenience may become a serious problem, for example, in a type of vehicle equipped with a transversely mounted engine.

Means for Solving the Problems The present invention was developed against the background of the above circumstances, and its gist is that the clutch case is provided on one side of a pair of rotating shafts that rotate relative to each other, and A clutch disk is provided on the other side of the rotating shaft and housed in a disk chamber of the clutch case, and the clutch disk is slidably fitted in the clutch case to press the clutch disk, and the clutch hydraulic pressure in the hydraulic chamber is A pressure member that is actuated and a lubricating oil passage for supplying lubricating oil into the disc chamber are provided, and the clutch oil pressure that acts on the pressing member to generate thrust is controlled to control the pressure between the pair of rotating shafts. A wet hydraulic clutch that changes the connection state of (a)
A lubricating oil passageway is provided in the clutch case to discharge lubricating oil in the disc chamber to the outside, and when the pressing member is brought close to a pressing position for pressing the clutch disc, communication with the lubricating oil path is substantially cut off. (b) a check valve provided in the pressing member that blocks flow from the hydraulic chamber toward the disk chamber but allows flow in the opposite direction; (c) a control valve that is provided in the passageway and stops the pressing member at a pressing standby position close to the pressing position or advances it to the pressing position by controlling the lubricating oil pressure in the disc chamber when the clutch oil pressure is applied; It is to include.

Function and Effect of the Invention By doing this, when the clutch hydraulic pressure is applied to the pressing member and the lubricating oil pressure is being supplied from the control valve to the disc chamber, the lubricating oil in the disc chamber will be discharged to the atmosphere through the discharge hole. Since the disc chamber is discharged and the pressure in the disc chamber is low, the check valve is closed by the clutch hydraulic pressure acting on the pressing member, and the pressing member is advanced to approach the clutch disc. As a result, the discharge hole for discharging the lubricating oil in the disc chamber is closed and the pressure in the disc chamber is increased, so the forward movement of the pressing member is blocked and at the same time the check valve opens, causing the pressing member to move toward the clutch disc. On the other hand, it is suitably held at the pressing standby position immediately before pressing, and is in a state in which the hydraulic clutch can be engaged immediately. In this state, if the disc chamber is communicated with a drain or the like through the control valve and the pressure inside the disc chamber is lowered, or if the clutch oil pressure is further increased, a thrust is generated in the pressing member and the pressing member is further increased. is brought forward. As a result, the pressing member is advanced to a pressing position where it presses the clutch disk, the hydraulic clutch is engaged, and the pair of rotating shafts are interconnected.

In this way, even if a discharge oil passage for discharging the clutch hydraulic pressure is not provided, the pressing member is controlled to the pressing standby position and the pressing position. The width of the discharge oil passage on the outer circumferential surface and the width dimension in the axial direction for installing a seal member to seal this discharge oil passage from other oil passages are no longer required, and the axial dimension of the hydraulic clutch is reduced. The inconvenience of increasing size is eliminated.

Here, the check valve is preferably formed so as to penetrate through the pressing member, and has an inner peripheral cylindrical surface parallel to the rotation axis and a tapered shape that is continuous with the inner peripheral cylindrical surface and inclined with respect to the rotation axis. The valve hole includes a valve hole having a valve seat surface, and a spherical valve element that is accommodated in the valve hole and can be brought into close contact with the valve seat surface.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, power from a vehicle engine 10 is transmitted to drive wheels via a wet hydraulic clutch 12, a stepped transmission, a differential gear device, etc. (not shown). The stepped transmission is, for example, a synchronous mesh type transmission similar to that described in Japanese Patent Application No. 60-254353.

The wet hydraulic clutch 12 transmits or interrupts power between an input shaft 14 that is a clutch shaft of the engine 10 and an output shaft 16 that also serves as an input shaft of a stepped transmission (not shown).
A disk 20 provided on the outer circumference of the ring gear 18 is fixed to the input shaft 14, and a clutch case 22 is fixed to the disk 20. The clutch case 22 includes a disc-shaped first member 24 fixed to the disc 20, a dish-shaped second member 26 fixed in combination with the first member 24, and a second member 26.
It consists of a cylindrical third member 28 fitted into the center of the body and rotatably supported via a bearing 30 by a stationary transmission housing 32. The third clutch case 22
The member 28 is fitted onto the outer peripheral surface of a cylindrical projection 33 formed on the transmission housing 32 in an oil-tight manner and capable of relative rotation, thereby making the clutch case 22 oil-tight. clutch case 22
The outer periphery of a piston 36 functioning as a pressing member is slidably fitted into the cylinder bore 34 formed inside the second member 26, and the inner periphery of the piston 36 is slidably fitted into the third member 28 of the clutch case 22. The inside of the clutch case 22 is divided into a hydraulic chamber 38 and a disk chamber 40 by a piston 36.

The output shaft 16 protruding from the transmission housing 32 passes through the piston 36 and reaches the inside of the disk chamber 40.
A hub 42 that supports a clutch disc 46 via a clutch damper 44 is spline-fitted to the shaft end of the clutch disc 46 . A pair of friction plates 48 are disposed on both sides of the clutch disk 46 and are pressed between the first member 24 and the piston 36 and slid by friction.
is provided. As a result, when the piston 36 advances to the pressing position where it presses the clutch disc 46 or when it advances to the pressing standby position very close to the clutch disc 46, the disc chamber 40 makes friction with the inner peripheral side chamber inside the friction plate 48. It is designed to be separated into an outer peripheral side chamber outside the plate 48. The outer peripheral side chamber is communicated with the atmosphere through a discharge hole 52 formed in the second member 26 to discharge lubricating oil. In addition,
54 is a return spring for urging the piston 36 toward the hydraulic chamber 38 side.

A clutch oil passage 58 and a lubricating oil passage 60, which are independent from each other, are provided between the cylindrical projection 33 projecting from the transmission housing 32 and the cylindrical member 56 fitted inside the projection.
The clutch oil passage 58 includes a through hole 62 and an annular groove 64 formed in the cylindrical projection 33, and the third member 28.
It is communicated with the hydraulic chamber 38 through a through hole 66 formed in the hydraulic chamber 38 . Further, the lubricating oil passage 60 is communicated with the disk chamber 40 through a through hole 68 formed in the cylindrical member 56.

A hydraulic pump 70 rotationally driven by the engine 10 or an electric motor (not shown) forces the oil returned to the oil tank 76 to the first linear control valve 72 and the second linear control valve 74. The first linear control valve 72 controls the working oil pressure P _p fed from the hydraulic pump 70 to generate clutch oil pressure for moving the piston 36 forward.
At the same time, the clutch oil passage 58 is communicated with the drain oil passage 78 to move the piston 36 backward. The second linear control valve 74 controls the working hydraulic pressure P _p fed from the hydraulic pump 70 to generate lubricating oil pressure and outputs it to the lubricating oil path 60 , while communicating the lubricating oil path 60 to the drain oil path 80 . The oil pressure inside the disk chamber 40 is brought to approximately atmospheric pressure.

Here, in the wet hydraulic clutch 12, as shown in detail in FIGS. 2 and 3, a check valve 84 is used to release the pressure inside the disk chamber 40 to the hydraulic chamber 38 to reduce the thrust of the piston 36. is provided on the piston 36. The check valve 84 is
A through hole 8 formed along one axis parallel to the rotation axis and spaced apart from the rotation axis by a distance R.
6 and a retainer 8 fitted into the through hole 86
8 and a spherical valve 90 housed within the retainer 88.
It is equipped with The through hole 86 has a small diameter hole 9
2, a large-diameter hole 94, and a tapered hole 96 that connects them.
and an inner cylindrical surface 100 having the same shape as the large diameter hole 94.
and an inward flange 102 for preventing the spherical valve element 90 from coming off.

Furthermore, in the wet hydraulic clutch 12,
As shown in detail in FIG. 2, the inner diameter of the hydraulic chamber 38 is set to C, and the outer diameter is set to A, which is larger than C. Therefore, the pressure receiving area S ₁₂ on which the clutch hydraulic pressure of the piston 36 is applied is π(A ² -C) It is ^2/4 .
In addition, when the piston 36 is advanced to the pressing position where it presses the clutch disc 46 or is advanced to the pressing standby position very close to the clutch disc 46, the disc chamber 40
is divided into an outer circumference side chamber and an inner circumference side chamber, so the outer diameter of the pressure receiving surface on which lubricating oil pressure is applied is B and the inner diameter is C, and the pressure receiving area S ₁₃ is π(B ² − C ² )/4 However, since it is set so that B>A slightly, the relationship between the pressure receiving areas is S ₁₃ >S ₁₂ .

The controller 82 is a so-called microcomputer that controls a shift actuator (not shown) based on predetermined relationships such as the operation position of a shift lever (not shown), the actual gear position of the stepped transmission, the throttle valve opening, and the vehicle speed. The motor shifts the gears of the stepped transmission, and also controls the engagement of the wet hydraulic clutch 12 in connection with this shift or in connection with the starting state of the vehicle.

The operation of the wet hydraulic clutch 12 from the released state to the engaged state will be described below.

First, the hydraulic chamber 3 is introduced through the first linear control valve 72.
8 is brought into communication with the drain oil passage 78, the piston 36 is returned by the biasing force F _r of the return spring 54, so that the wet hydraulic clutch 12 is released. At this time, when the inflow of lubricating oil from the second linear control valve 74 is cut off, the disk chamber 4
Since the lubricating oil in 0 is discharged through the discharge hole 52, the drag torque caused by the lubricating oil is reduced. As a result, when shifting from the neutral state to the first gear stage, the drag torque is reduced, the gear shift becomes easier, and the life of the synchronizer is increased.

Next, the lubricating oil pressure is applied by the second linear control valve 74 to bring the wet hydraulic clutch 12 into the close state.
P ₁₃ (P _p > P ₁₃ > 0) is supplied, and the first
A clutch hydraulic pressure P ₁₂ is supplied into the hydraulic chamber 38 by the linear control valve 72 . Such valve states are referred to as a lubricating oil side proximity control state and a hydraulic chamber side proximity control state. The lubricating oil pressure P ₁₃ is a predetermined value smaller than the discharge pressure P _p of the hydraulic pump 70 and larger than atmospheric pressure. However, since the disk chamber 40 is communicated with the atmosphere through the discharge hole 52, the disk chamber 4
The pressure in 0 is significantly lower than the lubricating oil pressure P ₁₃ . As a result, as shown in equation (1), the clutch hydraulic pressure P ₁₂ acting on the piston 36 and the hydraulic pressure chamber 38
Based on the centrifugal hydraulic pressure P ₁₂ ′ in the cylinder, a thrust force F ₁₂ larger than the biasing force F _r of the return spring 54 is generated,
Piston 36 is advanced. In this state,
Check valve 84 is still closed. That is, if the angle that the line connecting the contact point S with the valve seat surface 98 of the spherical valve element 90 and the spherical center makes with respect to an axis parallel to the rotation axis is θ, then the pressure receiving area of the spherical valve element 90 is πr. ²
sin ² θ, the thrust force F _A in the valve closing direction acting on the spherical valve element 90 is expressed as equation (2). On the other hand, if the angular velocity of rotation of the wet hydraulic clutch 12 is ω, then this thrust force F _A The rotational moment M _A of the spherical valve element 90 about the contact point S based on the action is as shown in equation (3), and the rotational moment M _B acting on the spherical valve element 90 on the valve seat surface 98 due to centrifugal force. becomes as shown in equation (4). In this forward state, the clutch hydraulic pressure is adjusted so that the relationships shown in equations (5) and (6) are maintained.
_P12 , etc. are set, and the piston 36 continues to move forward while the check valve 84 is closed.

F ₁₂ = S ₁₂ × (P ₁₂ + P ₁₂ ′) …(1) F _A = (P ₁₂ + P ₁₂ ′)・πr ² sin ² θ…(2) M _A = F _A × rsin = (P ₁₂ + P ₁₂ ′)・πr ³ sin ³ θ …(3) M _B = (mRω ² cosθ)・r …(4) M _A > M _B …(5) F ₁₂ > F _r …(6) Piston 36 as above When the clutch disk 4 reaches the pressing standby position by advancing, the clutch disk 4
6 is substantially sandwiched between the first member 24 and the piston 36 and is in a state immediately before being pressed, and the space between the inner peripheral side chamber of the disk chamber 40 and the discharge hole 52 is narrowed. As a result, the lubricating oil pressure inside the inner peripheral side chamber of the disk chamber 40
P ₁₃ is increased and centrifugal oil pressure P ₁₃ ' is generated in the disk chamber 40, so the spherical valve 36 has
Based on the lubricating oil pressure P ₁₃ and the centrifugal oil pressure P ₁₃ ′, a thrust force F _C in the opposite direction to the thrust force F _A is generated as shown in equation (7), and based on this thrust force F _C , the moment
A moment M _C in the opposite direction to M _A is generated as shown in equation (8).

F _C = (P ₁₃ + P ₁₃ ′)・πr ² sin ² θ …(7) M _C = (P ₁₃ +P ₁₃ ′)・πr ³ sin ³ θ …(8) As described above, the spherical valve 90 has As a result of the new moment M _C acting, the relationship shown in the following equation (9) is established, so the spherical valve element 90 rolls to the position shown in FIG. 4, and the check valve 84 is opened.

M _A < M _B + M _C (9) When the check valve 84 is opened in this way, the pressure difference between the hydraulic chamber 38 and the disk chamber 40 is eliminated, and the piston 36 is released by the biasing force of the return spring 54. Pushed back by F _r . Further, when the piston 36 is pushed back in this manner and the oil pressure P ₁₃ in the disk chamber 40 decreases, the check valve 84 begins to close. As a result, the piston 36 is maintained at the pressing standby position immediately before pressing the clutch disk 46. That is, if the oil pressure in the disk chamber 40 that has decreased due to the opening of the check valve 84 is P ₁₄ and the centrifugal oil pressure at this time is P ₁₄ ', then the rotational moment M _C ' based on these oil pressures is expressed as in equation (10). (11)
It settles down when the condition of the equation is satisfied.

M _C ′=(P ₁₄ +P ₁₄ ′)・πr ³ sin ³ θ …(10) M _A =M _B +M _C ′ …(11) Next, when engaging the wet hydraulic clutch 12, the second linear control When the flow cross-sectional area between the disk chamber 40 and the drain oil passage 80 is made larger than before through the valve 74 and the pressure P ₁₃ in the inner peripheral side chamber of the disk chamber 40 is further lowered, the oil pressure in the disk chamber 40 is reduced. Based thrust F ₁₃ [= (P ₁₄ × P ₁₄ ′) ×
S ₁₃ ] becomes smaller and the balance of the thrust acting on the piston 36 is lost, so the piston 36 moves forward and the friction plate 48 is compressed between the piston 36 and the first member 24. As a result, the wet hydraulic clutch 12 is engaged, and the power from the engine 10 is transmitted to a transmission (not shown).

As described above, as a result of the piston 36 being positioned at the pressing standby position where it can immediately start engaging regardless of the frictional state of the friction plate 48, etc., as described above,
When the pressure P ₁₃ ' in the disk chamber 40 is lowered by the second linear control valve 74 while the first linear control valve 72 is in the hydraulic chamber side proximity control state by the controller 82, the friction plate 48 immediately moves between the piston 36 and the first member. 24, the wet hydraulic clutch 12 begins to engage, and power transmission begins. Therefore, according to this embodiment, the response time of the wet hydraulic clutch 12 is short and constant regardless of the friction state of the friction plates 48, etc., and variations in engagement control characteristics are eliminated, so that the vehicle can be started easily. This allows the clutch to be engaged smoothly when changing gears or shifting the transmission, eliminating jerky starts of the vehicle and providing a precise shift feel.

Moreover, according to this embodiment, the clutch oil pressure P ₁₂
Since the piston 36 is controlled to the pressing standby position and the pressing position without providing a discharge oil passage for discharging the pressure, for example, a discharge oil passage is formed on the outer peripheral surface of the cylindrical protrusion 33 to constitute the discharge oil passage. Since it is not necessary to secure the width dimension in the axial direction and the width dimension for installing a sealing member to seal this discharge oil passage from other oil passages, etc.,
The effect is that the axial dimensions of the hydraulic clutch are reduced.

Furthermore, in this embodiment, by increasing the oil pressure in the disc chamber 40, the check valve 84 is immediately opened and the thrust of the piston 36 can be canceled, which has the advantage of improving the disengagement performance of the wet hydraulic clutch 12. . For example, when changing the gear stage of the transmission connected to the rear stage of the wet hydraulic clutch 12, the clutch can be released quickly, and the wet hydraulic clutch 12 can be opened properly during sudden braking, and the engine Stopping is eliminated and the driving feeling is improved.

Further, in this embodiment, since there is no need to provide a proximity control valve to the piston 36, the number of parts is reduced, and the construction of the wet hydraulic clutch 12 is simple and inexpensive.

Further, in this embodiment, since the outer diameter A of the hydraulic chamber 38 and the outer diameter B of the inner peripheral side chamber of the disk chamber 40 are made substantially equal, there is an advantage that the influence of centrifugal hydraulic pressure is extremely small.

Although one embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, in the embodiment described above, when the piston 36 is advanced from the pressing standby position to the pressing position, the hydraulic pressure in the disk chamber 40 is lowered, but the clutch hydraulic pressure P ₁₂ in the hydraulic chamber 38 is lowered.
This may be done by increasing the amount, or both may be done at the same time.

Furthermore, although the aforementioned check valve 84 was provided with a through hole 86 formed along one axis parallel to the rotation axis of the wet hydraulic clutch 12, this through hole 86 was not parallel to the rotation axis. You can.

Moreover, although the above-mentioned discharge hole 52 was provided in the second member 26, it may be provided in the first member 24. In short, when the piston 36 is placed in the pressing standby position and the inside of the disk chamber 40 is divided into the inner circumferential side chamber and the outer circumferential side chamber, the outer circumferential side chamber may be provided in a position that communicates with the outside.

Further, in the above embodiment, the piston 36 is formed integrally, but it may be divided into a piston body and a pressing plate driven by the piston body.

Further, in the above embodiment, the discharge pressure P _p of the hydraulic pump 70 is used as a common hydraulic source for P ₁₂ and P ₁₃ , but mutually independent hydraulic sources may be used.

Further, in the above embodiment, the outer diameter A of the hydraulic chamber 38
and the outer diameter B of the inner peripheral side chamber of the disk chamber 40 were assumed to have approximately the same dimensions, but even if one is made larger than the other, it can be dealt with simply by changing the clutch oil pressure P ₁₂ or the lubrication oil pressure P ₁₃ . .

Further, in the above-described embodiment, the first linear control valve 72
Although a second linear control valve 74 is used, an on/off type switching valve may be used.

The above-mentioned embodiment is at least one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a wet type hydraulic clutch according to an embodiment of the present invention. FIG. 2 is a sectional view illustrating the dimensional relationship of the wet type hydraulic clutch shown in FIG. 1. 3 and 4 are enlarged cross-sectional views of the check valve of FIG. 1, with FIG. 3 showing the closed operating state and FIG. 4 showing the open operating state, respectively. 12... Wet hydraulic clutch, 14... Input shaft,
16... Output shaft, 22... Clutch case, 36
... Piston (pressing member), 38 ... Hydraulic chamber, 4
0... Disk chamber, 52... Discharge hole, 60... Lubricating oil path, 74... Second linear control valve, 84... Check valve.

Claims (1)

[Claims for Utility Model Registration] (1) A clutch case provided on one of a pair of rotating shafts that rotate relative to each other, and a clutch provided on the other of the pair of rotating shafts and housed in a disc chamber of the clutch case. a disc, a pressing member slidably fitted within the clutch case to press the clutch disc and to which clutch hydraulic pressure in a hydraulic chamber is applied; and lubricating oil for supplying lubricating oil into the disc chamber. A wet hydraulic clutch of the type that changes the state of connection between the pair of rotating shafts by controlling clutch hydraulic pressure that acts on the pressing member and generates thrust therein, the wet hydraulic clutch comprising: a lubrication system in the disc chamber; a discharge hole provided in the clutch case for discharging oil to the outside, and which is substantially disconnected from the lubricating oil passage when the pressing member is brought close to a pressing position for pressing the clutch disk; a check valve provided on the pressing member to prevent flow from the hydraulic pressure chamber toward the disk chamber but allow flow in the opposite direction; and a check valve provided in the lubricating oil passage when the clutch hydraulic pressure is applied. a control valve for stopping the pressing member at a pressing standby position close to the pressing position or advancing it to the pressing position by controlling lubricating oil pressure in the disc chamber; . (2) The check valve has an inner cylindrical surface that extends through the pressing member and is parallel to the rotation axis, and a tapered valve seat surface that is continuous with the inner cylindrical surface and is inclined with respect to the rotation axis. 2. The wet hydraulic clutch according to claim 1, which includes a valve hole having a valve hole and a spherical valve that is accommodated in the valve hole and can be brought into close contact with the valve seat surface.