JPH1113786A - Lubrication device for clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication device to perform cooling during slip control of a wet type friction clutch to generate a friction heat without increasing a pump capacity. SOLUTION: In a lubrication mechanism for a clutch formed such that a wet type friction clutch 1 controlled by an engagement.releaser state is connected to the output port 47 of the solenoid valve 42 to output an oil pressure according to a command value by selectively communicating an output port 47 with an input port 46 and a drain port 48, a lubrication oil passage 45 through which drain oil of the solenoid valve 42 is guided as lubrication oil to the wet friction clutch 1 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for lubricating a wet friction clutch.

[0002]

2. Description of the Related Art As is well known, in a vehicle transmission, a plurality of torque transmission paths are formed by a gear transmission mechanism, and the transmission ratio is changed by switching the torque transmission paths. The reverse gear is set. As the gear transmission mechanism, a planetary gear type transmission mechanism and a selection gear type transmission mechanism are known.

[0003] The planetary gear type speed change mechanism is mainly composed of a plurality of sets of planetary gear mechanisms, and is configured to execute a speed change by changing the connection state of the rotating elements and the fixed elements by means of clutches and brakes. Further, the selection gear type transmission mechanism connects and connects shafts arranged in parallel with each other, a plurality of gear pairs attached to these shafts in a meshing state with each other, and a torque transmission path between the plurality of gear pairs and the shafts. This is a configuration provided with a plurality of speed change clutches or a synchronous coupling device to be disengaged.

Here, in an automatic transmission having a selection gear type transmission mechanism, a wet friction clutch may be used as a clutch arranged on the input side of the transmission mechanism. In such a vehicle, the neutral state is established if the transmission clutch is released.

When the vehicle starts moving, the starting clutch is released and the speed change clutch for setting the first speed is engaged. Thereafter, the starting clutch is engaged through a half-clutch state, and the torque of the engine is transmitted to the gear transmission mechanism. On the other hand, during traveling of the vehicle, control is performed to temporarily slip the starting clutch in response to engagement / disengagement of the shifting clutch, thereby suppressing shifting shock.

Japanese Patent Application Laid-Open No. 7-55154 discloses an example of this type of transmission. Briefly describing this type of transmission, a starting clutch for selectively transmitting torque from an engine includes a plurality of gears. It is provided as input means for a gear transmission having a pair and a shaft. For example, in order to smoothly start the vehicle at the time of starting, slip control of the starting clutch is frequently used, such as gradually engaging the starting clutch from the slip state.

[0007]

As described above, in a transmission using a starting clutch, control for slipping the starting clutch is frequently used at the time of starting or shifting. If the starting clutch is slip-controlled, part of the power will be heat, so it will be necessary to cool the friction material to prevent burnout.In a wet friction clutch, lubricating oil is continuously supplied to the friction surface By doing so, cooling is performed. Such cooling with lubricating oil is generally performed in a wet multi-plate clutch, but since the starting clutch has a considerably larger torque capacity than the clutch for setting the speed, the amount of lubricating oil required during slip control is reduced. More.

[0008] The slip control of the starting clutch is as follows.
This is executed at the time of starting and shifting, and at that time, the hydraulic pressure of the transmission is also consumed for slip control of the starting clutch.

Accordingly, the hydraulic pressure required for slip control of the starting clutch is used for lubrication and control for cooling, and the amount thereof becomes enormous.
If the capacity of the oil pump is increased to satisfy such needs, the oil pump becomes large and consumes a large amount of power to drive the oil pump. However, there is a disadvantage that fuel consumption is hindered and fuel economy is deteriorated. A large amount of lubricating oil is required only when performing slip control,
If lubrication is performed according to the maximum oil amount at that time, a large amount of lubricating oil will intervene on the friction surface with the starting clutch released, and drag torque will be generated via the lubricating oil, As a result, fuel efficiency may be degraded.

Further, if a special lubrication system is provided for performing lubrication required for slip control, not only the size of the device is increased, but also the control device becomes complicated, which may lead to an increase in cost. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus capable of favorably performing lubrication during slip control of a wet friction clutch without increasing the discharge capacity of an oil pump. It is the purpose.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a wet friction clutch whose engagement / disengagement state is controlled by hydraulic pressure, wherein an output port is connected to an input port and a drain port. In a lubricating device for a clutch connected to the output port in a solenoid valve that outputs a hydraulic pressure according to an instruction value by selectively communicating with the drain port, the drain oil of the solenoid valve is guided as lubricating oil to the wet friction clutch. A lubricating oil passage is provided.

Therefore, in the present invention, by giving a signal of a predetermined command value to the solenoid valve, a hydraulic pressure corresponding to the command value is output from the solenoid valve, and as a result, the wet friction clutch is engaged / disengaged and slipped. Is controlled to either. When the wet friction clutch is controlled to be in the slip state, the output signal pressure of the solenoid valve becomes a pressure intermediate between the maximum pressure and the minimum pressure, so that drain oil is generated. The drain oil is supplied as lubricating oil to the wet friction clutch via the lubricating oil passage. Therefore, in the present invention, the drain oil at the time of the slip control of the solenoid valve can be used as the lubricating oil, so that the amount of the lubricating oil at the time of the slip control of the wet friction clutch is increased, and as a result, the discharge capacity of the oil pump is increased. Therefore, the wet friction clutch can be cooled.

[0014]

Next, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a sectional view showing the structure of a wet friction clutch 1 according to one embodiment of the present invention. In FIG. 1, an engine (not shown) is provided on the right side, and a transmission (not shown) is provided on the left side.

In FIG. 1, an annular plate 3 is fixed to a tip of a clutch casing 2 formed in an annular shape. A clutch shaft 4 is provided inside the casing 2 so as to be oriented in the axial direction and to be rotatable relative to the casing 2. A clutch hub 5 is spline-fitted to the tip of the clutch shaft 4 on the plate 3 side. Have been combined. An annular clutch disk 7 is attached to the outer periphery of the clutch hub 5 via a damper spring 6. An annular friction plate 8 is attached to the front and back of the clutch disk 7.

A pair of pusher plates 9 and 10 each having an annular shape are arranged with the friction plate 8 interposed therebetween, and one pusher plate 9 is attached to the plate 3. The other pusher plate 10 is spline-fitted to the inner peripheral surface of a cylindrical member 11 provided integrally with the casing 2 inside the casing 2. In addition,
The retracted position of the pusher plate 10, that is, the movement limit position in the direction opposite to the friction plate 8 is defined by a snap ring 12 attached to the cylindrical member 11. A passage 13 penetrating in the radial direction is formed at a position corresponding to the outer peripheral side of the clutch disk 7 in the cylindrical member 11.

An end plate 14 is integrally attached to an end (left end in FIG. 1) of the cylindrical member 11. A diaphragm spring 15 is provided between the end plate 14 and the other pusher plate 10.
Is arranged. This diaphragm spring 15
Is a plate-like member which is similar to that acting on a clutch in a conventional manual transmission, is a ring-shaped member as a whole, and is configured to be elastically deformed in the plate thickness direction. . A snap ring 16 for sandwiching the outer peripheral portion of the diaphragm spring 15 between the diaphragm plate 15 and the end plate 14 is attached to the inner peripheral surface of the cylindrical member 11. An intermediate portion in the radial direction of the diaphragm spring 15 is in contact with a projection 10A formed on the back surface of the other pusher plate 10. That is, the diaphragm spring 15 is configured such that its outer peripheral end is a fixed point, the inner peripheral part is elastically deformed with a force point, and the intermediate part functions as an action point, thereby pressing the other pusher plate 10 in its axial direction. Have been.

The end plate 14 is rotatably fitted to the outer peripheral surface of the clutch shaft 4 while maintaining a liquid-tight state, and is located on the outer peripheral side of the boss portion fitted to the clutch shaft 4. However, it is depressed leftward in FIG. 1, and a cylinder chamber 17 is formed therein. A piston 18 is accommodated in the cylinder chamber 17 so as to be movable back and forth. The inner peripheral side end of the diaphragm spring 15
The diaphragm spring 15 extends to a position facing the outer peripheral portion of the piston 18, so that when the piston 18 advances, the diaphragm spring 15 is elastically deformed and presses the other pusher plate 10.

Here, a mechanism for operating the piston 18 will be described.
An oil passage 31 is formed in the inside of the end plate 14 in the axial direction, and the oil passage 31 is open to the outer peripheral side of the clutch shaft 4 at the boss portion of the end plate 14.
In the boss portion, a through-hole communicating with the oil passage 31 is formed in the radial direction, and the through-hole is formed in the piston 1.
8 is open on the back side. That is, these oil passages 31
And, it is configured to supply / discharge hydraulic pressure to / from the cylinder chamber 17 through the through hole. A retainer 19 is disposed on the front side (right side in FIG. 1) of the piston 18 so as to be fitted to the boss of the end plate 14.
A return spring 20 is arranged between the piston 9 and the piston 18. The portion of the oil passage 31 on the tip side of the clutch shaft 4 is sealed by the plug 21.

The clutch shaft 4 is formed with a lubricating oil passage 32 penetrating in the axial direction. The lubricating oil passage 32 communicates with an oil passage 33 formed in the clutch shaft 4 such that the lubricating oil passage 32 opens at the end of the clutch shaft 4 and opens between the end of the boss of the end plate 14 and the clutch hub 5. ing. Therefore, the lubricating oil is sent to the tip of the clutch shaft 4 and the vicinity of the clutch hub 5. The inside of the casing 2 communicates with a drain portion such as an oil pan (not shown).

In FIG. 1, the wet friction clutch 1
The cross-sectional view above the center axis of the figure indicates that the clutch is in a released state, and the cross-sectional view below shows the clutch in an engaged state or a slip state.

FIG. 2 shows a control system for controlling the above clutch. Since the clutch is controlled to be in a slip state other than the two states of engagement and disengagement, a normally open type duty three-way valve 42 that linearly controls the hydraulic pressure supplied to the cylinder chamber 17 is provided. . The duty three-way valve 42 connects the input port 46 with the output port 47 when the duty ratio is 0%, that is, in the off state, and has a duty ratio of 100%.
In this case, the output port 47 communicates with the drain port 48 in the ON state, and the output pressure changes linearly when the duty ratio changes from 0% to 100%.

An electronic control unit (ECU) 41 for outputting a control signal to the duty three-way valve 42 is provided.
This is due to the central processing unit (CPU) and storage device (RA
M, ROM), and outputs a control signal having a predetermined duty ratio to the duty three-way valve 42 based on a vehicle speed, a throttle opening, a shift signal, or the like.

The input port 46 of the duty three-way valve 42 is connected to a line pressure oil passage 43 for supplying a line pressure, which is the entire source pressure of the transmission, and the output port 47 is connected via a control oil passage 44. The lubricating oil passage 31 is connected to the drain port 48, and the lubricating oil passage 32 is connected to the drain port 48 via a lubricating oil passage 45.

When the wet friction clutch 1 is controlled to the engaged state, the electronic control unit (ECU) 41 outputs a signal having a duty ratio of 0%. That is, the duty three-way valve 42 is turned off, and its input port 46
And the output port 47 are kept in communication. Therefore, the line pressure is supplied from the line pressure oil passage 43 to the cylinder chamber 17 via the control oil passage 44 and the oil passage 31. As a result, the piston 18 moves rightward in FIG. 1 by the hydraulic pressure, and presses the inner peripheral portion of the diaphragm spring 15 rightward in FIG. 1 in the axial direction. Along with this, the other pusher plate 10 is pushed rightward in FIG. 1 via the protrusion 10A, whereby the clutch disc 7 is sandwiched between the pair of pusher plates 9 and 10, and torque between them is reduced. The engagement state where the transmission is performed is established. Therefore, the output torque of the engine is transmitted to the clutch casing 2 and the pusher plates 9 and 10, and transmitted from the clutch disk 7 to the transmission (not shown) via the clutch shaft 4.

On the other hand, when the wet friction clutch 1 is controlled to be in the released state, a control signal having a duty ratio of 100% is output from the electronic control unit 41. In this case, the input port 46 is closed, and the output port 47 and the drain port 48 are kept in communication. Therefore, the pressure is discharged from the cylinder chamber 17 through the oil passage 31, the control oil passage 44, and the lubricating oil passage 45, and the piston 18 is pushed back to the left in FIG. As a result, the load acting on the inner peripheral portion of the diaphragm spring 15 is eliminated, so that the pressing force on the other pusher plate 10 is eliminated, and the clutch 1 is released.

When the vehicle starts or shifts, the wet friction clutch 1, which is the input clutch, needs to be in a slip state in order to smooth the change in driving force and reduce shock. The control of the slip state is performed by setting a command value for the duty three-way valve 42, that is, a duty ratio to be more than 0% and less than 100%. Therefore, the duty three-way valve 42 switches between the on state and the off state in accordance with the duty ratio, and the output port 47 communicates with the drain port 48 as the time ratio of the on state increases, that is, as the duty ratio increases. The time is longer, resulting in a lower output pressure. That is, the load with which the piston 18 presses the diaphragm spring 15 is lower than in the fully engaged state, so that the push force between the pusher plates 9 and 10 reduces the so-called engagement force that clamps the clutch disk 7, and the engagement force with respect to the input torque is reduced. , A slip occurs between the pusher plates 9 and 10 and the clutch disk 7.

On the other hand, in the duty three-way valve 42, part of the hydraulic pressure once sent to the cylinder chamber 17 is discharged from the drain port 48 by connecting the output port 47 to the drain port 48. The drain oil flows to the lubricating oil passages 45 and 32, and
3 scatters in the radial direction of the clutch shaft 4. Then, the drain oil is supplied to the friction surface of the clutch disc 7 by, for example, centrifugal force, and is further sent to the drain portion such as an oil pan through the inside of the casing 2 so that the heat generated by the slip control generates the drain oil. The wet friction clutch 1 is carried away by the oil, that is, the lubricating oil, and the wet friction clutch 1 is cooled well.

More specifically, such a cooling process will be described. In a range where the duty ratio is more than 0% and less than 50%, as the duty ratio increases, the output port 4 is increased.
7 and the drain port 48 communicate with each other, and the amount of drain oil used as lubricating oil also increases. Further, in the wet friction clutch 1, since the engagement hydraulic pressure decreases as the duty ratio increases, the slip state is further promoted, and the amount of heat generated increases. Even if the frictional heat increases in this manner, the amount of drain oil serving as the lubricating oil increases accordingly, so that the lubricating oil does not run short and the wet friction clutch 1 can be cooled efficiently.

When the duty ratio is 50%, that is, when the time ratio at which the input port 46 communicates with the output port 47 and the time ratio at which the output port 47 communicates with the drain port 48 become the same. The amount of drain oil introduced into the wet friction clutch 1 as lubricating oil is maximized. Further, the frictional heat generated in the wet friction clutch 1 becomes maximum.

Then, when the duty ratio exceeds 50% and becomes 1
If it is less than 00%, the proportion of the time between the output port 47 and the drain port 48 becomes longer than the proportion of the time between the input port 46 and the output port 47. Therefore, as the duty ratio increases, the amount of drain oil serving as lubricating oil decreases. Also, a wet friction clutch 1
Is further reduced, so that the generated frictional heat is also reduced. In other words, as the friction heat decreases, the amount of drain oil serving as lubricating oil also decreases, so that there is no excess or shortage of lubricating oil, and the wet friction clutch 1 is cooled sufficiently and sufficiently.

In the disengaged state where the duty ratio is set to 100%, the output port 47 and the drain port 48 communicate with each other, and the amount of drain oil used as lubricating oil becomes zero. Oil is not supplied, and it is possible to effectively prevent the lubricating oil from excessively intervening on the friction surface and the occurrence of drag torque with the lubricating oil.

FIG. 3 shows the relationship between the engaged / slip / disengaged state of the wet friction clutch 1 and the required amount of lubricating oil. As the duty ratio increases, the control pressure decreases, and the wet friction clutch 1 shifts from the engaged state to the slip state and finally to the released state. Accordingly, the amount of drain oil supplied as lubricating oil for the wet friction clutch 1 also increases. However, when the duty ratio becomes 50%, the drain oil amount becomes maximum, and when it exceeds 50%, the supplied drain oil amount decreases and becomes zero when the wet friction clutch 1 is in the disengaged state. On the other hand, the frictional heat generated between the clutch disk 7 and the pusher plates 9 and 10 is substantially zero in the engaged state and the released state, and a large amount of frictional heat is generated in the slip state.

From the above, an appropriate amount of lubricating oil is supplied from the lubricating oil passage 45 depending on the amount of frictional heat generated in the wet friction clutch 1, and the wet friction clutch 1 It is possible to prevent the drag torque from increasing due to overheating, burning, and excess lubricating oil, and to cool the wet friction clutch 1 efficiently.

In the above-described example, a single-plate clutch for starting has been described as a wet friction clutch.
The present invention is not limited to the above example, and may be, for example, a wet multi-plate clutch for shifting. In other words, engagement
Any wet friction clutch whose release state is controlled by hydraulic pressure may be used.

In the above example, a normally open type three-way duty valve has been exemplified as the solenoid valve.
The solenoid valve of the present invention is not limited to this, and may be any solenoid valve that selectively outputs an output port to an input port and a drain port to output a hydraulic pressure according to a command value.

In the above example, the electronic control unit (ECU) is shown as outputting the command value. However, the means for outputting the command value according to the present invention may be manually operated, for example. Command value output device.

[0038]

As described above, according to the present invention, since the lubricating oil passage for guiding the drain oil of the solenoid valve to the wet friction clutch as lubricating oil is provided, the slip state of the clutch in which a large amount of frictional heat is generated is provided. In this case, the shortage of the lubricating oil is compensated by the drain oil of the solenoid valve, and the generated frictional heat is efficiently transferred, so that the clutch can be prevented from overheating and burning. Therefore, there is no need to provide a new hydraulic system for supplying lubricating oil for cooling during slip control, or to provide a pump or the like for generating the hydraulic pressure, so that it is possible to prevent the transmission or the hydraulic system from increasing in size. It is possible to prevent power loss and deterioration of fuel efficiency due to the power loss.

Further, by providing a lubricating oil passage for guiding the drain oil of the solenoid valve to the wet friction clutch as lubricating oil, an amount of lubricating oil substantially corresponding to the amount of frictional heat generated by the wet friction clutch is supplied. Therefore, it is possible to prevent overheating and burnout of the clutch due to lack of lubricating oil, increase in drag torque due to excess lubricating oil, and deterioration of fuel efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a wet friction clutch according to an embodiment of the present invention.

FIG. 2 is a schematic hydraulic system diagram for explaining a hydraulic system for controlling the wet friction clutch.

FIG. 3 is a diagram showing a relationship between an engaged / slip / disengaged state of the wet friction clutch of FIG. 1 and an amount of lubricating oil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wet friction clutch 7 Clutch disk 9, 10 Pusher plate 31, 32, 33 Oil passage 41 Electronic control unit (ECU) 42 Duty three-way valve 43 Line pressure oil passage 44 Control oil passage 45 Lubricating oil passage 46 Input port 47 Output port 48 Drain port

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Rie Kojima 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (1)

[Claims] An electromagnetic valve that outputs a hydraulic pressure according to a command value by selectively connecting an output port to an input port and a drain port by a wet friction clutch whose engagement / release state is controlled by hydraulic pressure. A lubricating device for a clutch connected to the output port, wherein a lubricating oil passage for guiding drain oil of the electromagnetic valve to the wet friction clutch as lubricating oil is provided.