JP2878384B2 - Fluid coupling fastening force control device - Google Patents

Description

The present invention relates to a fluid for controlling the operation of a lock-up clutch in a fluid coupling including an input element such as a pump impeller, an output element such as a turbine runner, and a lock-up clutch. The present invention relates to a coupling force control device for a joint.

(Prior Art) A fluid coupling provided in an automatic transmission mounted on a vehicle,
Lock-up for mechanically connecting the pump impeller and the turbine runner in addition to the pump impeller and the turbine runner that form the input element connected to the output shaft of the engine as a so-called fluid torque converter It is known to provide a clutch. In a hydraulic torque converter provided with such a lock-up clutch, the lock-up clutch reduces the energy loss in the torque converter when torque is transmitted from the engine to the wheel drive system via the automatic transmission. In order to reduce the vibration, the input section connected to the pump impeller is frictionally engaged to connect the pump impeller and the turbine runner in a lock-up fastening state. In order to reduce body vibration, the input section connected to the pump impeller is A lock-up release state in which the pump impeller and the turbine runner are not engaged with each other at a separated position, and further, a reduction in energy loss and a body vibration in the torque converter when the vehicle is in a specific driving state. Pump impeller and turbine runner It is assumed to take the slip engagement state of frictional engagement with the input unit connected to the pump impeller so as to cause a rotational speed difference selectively between.

The operation of the lock-up clutch is performed, for example, as described in Japanese Patent Application Laid-Open No. 62-297567, in which the operating oil pressure from the hydraulic circuit portion is supplied to two chambers provided with the lock-up clutch therebetween. By being supplied in a manner, the operation is performed in accordance with a difference in operating oil pressure generated between two chambers sandwiching the lock-up clutch. In the hydraulic circuit for supplying the operating oil pressure to the lock-up clutch, a hydraulic circuit is usually provided with the lock-up clutch interposed.
A shift valve that supplies and discharges hydraulic pressure to each of the two chambers,
A pressure regulating valve is provided in one of the two chambers provided with the lock-up clutch therebetween through a shift valve to adjust the operating oil pressure supplied to the lock-up clutch to bring the lock-up released state. The operating oil pressure supplied to each of the two chambers provided for the lock-up clutch is controlled in accordance with the operation mode in which the oil pressure acting on each of the valve and the pressure regulating valve is changed.

(Problems to be Solved by the Invention) Torque provided with a lock-up clutch whose operation is controlled by operating oil pressure controlled according to the operation mode of the shift valve and the pressure regulating valve provided in the hydraulic circuit section as described above. In the converter, under the running state of the vehicle where the engine load and the vehicle speed satisfy predetermined conditions,
In order to achieve both a reduction in energy loss during transmission of torque from the pump impeller to the turbine runner and a reduction in vehicle body vibration, the lock-up clutch is placed in a slip-engaged state and the rotational speed difference between the pump impeller and the turbine runner is increased. Is performed, but when the engine is shifted to the acceleration state under the execution of the slip control, the lock-up clutch in the torque converter is changed from the slip engagement state to the lock-up engagement state. It is changed to. Then, in the control for shifting the lock-up clutch from the slip engagement state to the lock-up engagement state, the oil pressure acting on the shift valve and the pressure regulating valve is changed, and as a result, the control is provided for the lock-up clutch. The supply and discharge control of the operating hydraulic pressure to the two chambers is performed. At this time, the lock-up clutch is released from the lock-up clutch in one of the two chambers provided with the lock-up clutch interposed therebetween through the shift valve. Hydraulic pressure acting on a pressure regulating valve for adjusting the operating hydraulic pressure supplied to take
The hydraulic pressure acting on the shift valve for controlling the operating hydraulic pressure supplied to the other of the two chambers provided with the lock-up clutch so as to bring the lock-up clutch into the locked-up engagement state is, for example, a solenoid valve or the like. In the process of shifting the lock-up clutch from the slip engagement state to the lock-up engagement state, the lock-up clutch is provided across the lock-up clutch in the torque converter. In this case, the operating oil pressure difference between the two chambers is temporarily reduced to zero, and as a result, the lock-up clutch is temporarily brought into the lock-up releasing state and the engine is brought into the blow-up state. There is a risk that a desired situation is copied.

In view of the above, the present invention shifts an input element such as a pump impeller, an output element such as a turbine runner, and a lockup clutch in a fluid coupling including a lockup clutch from a slip engagement state to a lockup engagement state. In the process, the lock-up clutch is capable of temporarily avoiding a state in which the lock-up release state is accompanied by an undesired blow-up of the engine to which the fluid coupling is connected. It is an object of the present invention to provide a fastening force control device.

(Means for Solving the Problems) To achieve the above object, a fluid coupling fastening force control device according to the present invention includes an input element and an output element connected to an output shaft of an engine mounted on a vehicle. The lock-up clutch in the fluid coupling having a lock-up clutch capable of taking a slip engagement state in which the input element and the output element are engaged in a relatively rotatable state. In order to perform the operation, the first hydraulic passage for applying the operating oil pressure to the first oil chamber provided for the lock-up clutch, the lock-up clutch, and the input element and the output element are disengaged. An oil having a second hydraulic passage for applying a working oil pressure to a second oil chamber provided for the lock-up clutch, and a first and a second hydraulic passage so as to perform an operation for establishing a state. A pressure circuit portion, a shift valve provided in the hydraulic circuit portion and having first and second spools arranged in series, and a pressure regulating valve connected to the second hydraulic circuit via the shift valve; A first hydraulic pressure acts between the one end of the first spool and the one end of the second spool facing the shift valve, and a second hydraulic pressure acts on the other end of the first spool. Further, the reference hydraulic pressure acts on the other end of the second spool, and the pressure regulating valve has a third spool on which the first hydraulic pressure acts, and an operating hydraulic pressure in the second hydraulic passage. And to adjust the hydraulic pressure
A first hydraulic pressure control means for controlling a first hydraulic pressure in accordance with an operation state of the vehicle, a second hydraulic pressure control means for controlling a second oil pressure in accordance with the operation state of the vehicle, and a hydraulic pressure adjustment for a pressure regulating valve. And a hydraulic pressure transmitting means for transmitting a third hydraulic pressure acting to perform the first hydraulic pressure control. The first hydraulic pressure control means controls the first and second hydraulic pressures controlled by the first and second hydraulic pressure control means, respectively. Takes the position where the supply and discharge of the working oil pressure is performed in the first hydraulic passage, and the second spool of the shift valve takes the position where the supply and discharge of the working oil pressure is performed in the second hydraulic passage, Further, the third pressure in the pressure regulating valve depends on the first oil pressure controlled by the first oil pressure control means and the third oil pressure sent from the oil pressure sending means.
Is configured to adjust the operating oil pressure in the second hydraulic passage.

(Operation) In the fluid coupling engagement force control device according to the present invention configured as described above, the shift valve engages the lock-up clutch in the fluid coupling to engage the input element and the output element with each other. A first spool for supplying operating hydraulic pressure to take the state, and a second spool for supplying and discharging the operating hydraulic pressure for bringing the lock-up clutch into a lock-up releasing state in which the input element and the output element are disengaged. And a third spool for adjusting the operating oil pressure supplied to the second hydraulic passage, and a first spool for the pressure control valve. The first hydraulic pressure acts on the third spool between the one end of the second spool and the one end of the second spool opposed thereto, and the second hydraulic pressure acts on the other end of the first spool. , The second When the reference hydraulic pressure is applied to the other end of the pool, the lockup clutch shifts from the slip engagement state in which the input element and the output element are engaged in a relatively rotatable state to the lockup engagement state. , The first and second oil pressures are controlled by the first and second oil pressure control means, respectively, and the third oil pressure is sent from the oil pressure sending means. Operating hydraulic pressure applied to a first oil chamber provided for the lock-up clutch, and applied to a second oil chamber provided for the lock-up clutch through a second hydraulic passage from a shift valve. The operating oil pressure is directly changed from the state having the mutual difference required for the slip engagement state to the state having the mutual difference required for the larger lock-up engagement state. So that it is possible to reduction.

Accordingly, the transition from the slip engagement state to the lock-up engagement state of the lock-up clutch in the fluid coupling is performed, for example, by temporarily setting the first and second oil chambers provided for the lock-up clutch to the first and second oil chambers, respectively. The difference between the operating oil pressures applied through the second hydraulic passage is substantially reduced to zero, so that the lock-up releasing state is not performed. As a result, the lock-up clutch in the fluid coupling slips. When the engine to which the fluid coupling is connected is accelerated under the fastened state, undesirable blow-up of the engine is avoided.

(Embodiment) FIG. 2 shows an example of a fluid coupling fastening force control device according to the present invention, together with a power plant of a vehicle to which the device is applied.

The power plant shown in FIG. 2 includes an engine 1 and an automatic transmission 2, and the engine 1 has, for example, four cylinders, and each of the four cylinders has a throttle valve. An air-fuel mixture formed by intake air from an intake passage 5 provided with fuel and fuel injected from a fuel injection valve provided in the intake passage 5 is supplied to each cylinder. The gas is burned by the operation and discharged to the exhaust passage. Then, the torque generated by the engine 1 obtained by the combustion of the air-fuel mixture is:
The power is transmitted to the wheel drive system via a power transmission path including the automatic transmission 2.

The automatic transmission 2 includes a multi-gear transmission mechanism 9, a hydraulic torque converter 10 as a fluid coupling, a lock-up control solenoid valve 11 for forming and supplying an operating oil pressure used for the control thereof, and a control mechanism. Hydraulic circuit unit equipped with various solenoid valves such as pressure solenoid valve 12 and shift valves
15 is provided.

The speed change mechanism 9 is provided with various types of frictional engagement elements such as a planetary gear unit, a clutch and a brake for obtaining four forward speeds and one reverse speed, for example. The hydraulic pressure and the release hydraulic pressure are selectively supplied as appropriate from the hydraulic circuit unit 15 through various control valves or shift valves provided therein. Thereby, each frictional engagement element is set to be in the engaged state or the released state,
It is possible to obtain a drive range, a second range, and a first range, which constitute a parking range, a reverse range, a neutral range, and a forward range, and first to fourth speeds in the forward range.

In FIG. 1, the torque converter 10 includes an oil pump 30 and a constant pressure forming portion 31 connected to the oil pump 30 respectively.
And a regulator plate 32 provided with a portion related to the operation control of the torque converter 10 in the hydraulic circuit portion 15 as shown with a drive plate coupled to the output portion 1a of the engine 1 and rotationally driven by the engine 1. 16, a pump impeller 17 joined to and rotating with the drive plate 16, a turbine runner 18 in which torque generated by the engine 1 is transmitted via the pump impeller 17 and hydraulic oil, and between the pump impeller 17 and the turbine runner 18. , And a stator 19 disposed in
A torsion damper, which is provided between the drive plate 16 and the turbine runner 18 and is spline-fitted to the turbine hub 21. Coil spring for 22 and torsion damper 22
It is provided with a lock-up clutch 25 which is connected via the. The lock-up clutch 25 is made to approach and separate from the drive plate 16 as a whole, and is configured to rotate together with the turbine runner 18. The portion surrounded by the outer shell of the drive plate 16 and the pump impeller 17 is filled with hydraulic oil.

A lock-up clutch 25 is provided between the drive plate 16 and the turbine runner 18 in the torque converter 10.
The back pressure chamber 27 and the internal pressure chamber 28 are formed by being interposed, and the back pressure chamber 27 is separated from the drive plate 16 in a direction to separate the lock-up clutch 25 from the drive plate 16 through an oil passage 35 in the hydraulic circuit unit 15. A pressing hydraulic pressure is supplied, and the internal pressure chamber 28 is provided with an oil passage in the hydraulic circuit 15.
An operating oil pressure that presses the lock-up clutch 25 in a direction to approach the drive plate 16 is supplied through 36. When the value of the operating oil pressure in the internal pressure chamber 28 is higher than the value of the operating oil pressure in the back pressure chamber 27 by a predetermined value or more, the lock-up clutch 25 is pushed rightward in FIG. The pump impeller 17 and the turbine runner 18 are engaged with each other in a lock-up fastening state, and the value of the working oil pressure in the internal pressure chamber 28 is changed to the value of the working oil pressure in the back pressure chamber 27. As described above, when the difference is less than the predetermined value, the pump impeller 17 and the turbine runner 18 are disengaged from each other by being pushed to the left in FIG. It is assumed that the lock-up release state is set to the engagement state. Further, in the lock-up clutch 25, the value of the operating oil pressure in the internal pressure chamber 28 is equal to or greater than the value of the operating oil pressure in the back pressure chamber 27,
When the difference is within a predetermined range, the pump impeller 17 and the turbine runner 18 are engaged in a relatively rotatable state, and a slip fastening state with respect to the drive plate 16 is assumed. Is larger, the slip ratio with respect to the drive plate 16 is smaller. The internal pressure chamber 28 is connected to an oil cooler 33 through an oil passage 37 in which a check valve 29 is arranged.

A portion related to the operation control of the torque converter 10 in the hydraulic circuit unit 15 includes a lock-up shift valve 50, a lock-up pressure regulating valve 60, a lock-up control solenoid valve 11, and a pressure regulating solenoid valve 12. The lock-up shift valve 50 has two spools 51 and 52 arranged in series, has ports a to h opened and closed by the spools 51 and 52, and three drain ports. Urged to the spool 52 side. The spools 51 and 52 of the lock-up shift valve 50 are provided with a land 51a and a land 52a, respectively, on one end side thereof facing each other. Further, the spool 51 has a land 51b on the other end side. Is provided, and a land portion 51c is provided between the land portion 51a and the land portion 51b. The pressure receiving area of the land portion 51a is larger than the pressure receiving area of the land portions 51b and 51c. The spool 52 also has a land 52 on the other end.
b is provided, and a land portion 52c is provided between the land portion 52a and the land portion 52b.The pressure receiving area of the land portion 52b is larger than the pressure receiving area of the land portion 51a on the spool 51. The pressure receiving areas of the portions 52a and 52c are equal to the pressure receiving area of the land portion 51a of the spool 51. The port a is located on the other end side of the spool 51, and the port d is
, And 52, and a port h is located on the other end side of the spool 52.

The lock-up pressure regulating valve 60 has a spring 62 disposed at one end thereof, a spool 61 biased toward the other end by the spring 62, and a port j opened and closed by the spool 61.
, And three drain ports, and the spool 61 is provided with land portions 61a, 61b, and 61c.

In the lock-up shift valve 50, the port a passes through the oil passage 38, the port d passes through the oil passage 39 in which the pressure regulating solenoid valve 12 is provided, and
Is an oil passage provided with a lock-up control solenoid valve 11.
The port b is connected to a common oil passage 47 extending from the constant pressure forming section 31 through the oil passage 41, and the port b is locked through the oil passage 41.
60 are connected to ports j and k, port c is connected to the back pressure chamber 27 through an oil passage 35, and port e is connected to an oil passage 48 and an oil passage 36.
And port f is connected to oil cooler 33 through oil passage 42, and port g is connected to common oil passage 49 extending from regulator valve 32 through oil passage 43. on the other hand,
In the lock-up pressure control valve 60, the port 1 is connected to the common oil passage 49 extending from the regulator valve 32 through the oil passage 44, the port m is connected to the common oil passage 49 through the oil passage 45, and the port n is connected to the oil passage
The oil passage 39 is connected to the oil passage 39 downstream of the portion where the pressure regulating solenoid valve 12 is provided. Oil passage 3
An orifice is provided at a predetermined position in each of 6, 38, 39, 40, 41 and 46.

Solenoid valve for lock-up control provided in oil passage 40
The operation of each of the pressure regulating solenoid valve 12 and the pressure regulating solenoid valve 12 provided in the oil passage 39 is controlled by the control unit 70. As shown in FIG. 2, the control unit 70 includes, for example, a throttle opening sensor 55 for detecting the opening of the throttle valve 4, a rotation speed sensor 56 for detecting the engine speed, and a vehicle speed sensor for detecting the running speed of the vehicle. Based on various detection output signals obtained from a sensor group 58 representing 57 and other traveling states of the vehicle,
The drive signal Ca and the drive signal Cb are supplied to the lock-up control solenoid valve 11 and the pressure adjustment solenoid valve 12 provided in the hydraulic circuit unit 15, respectively, and a control valve and a shift valve arranged in relation to the transmission mechanism 9. The drive signal group Cc is supplied to various solenoid valves provided for the control of the solenoid valves to control their operation. Thereby, the operation control of the lock-up clutch 25 and the shift control of the transmission mechanism 9 in the torque converter 10 are performed.

When the operation control of the lock-up clutch 25 is performed by the control unit 70, the control unit 70
As a result, the lock-up clutch 25 is in the lock-up release state based on various detection output signals supplied thereto,
It is determined which of the slip engagement state and the lockup engagement state should be taken.

For example, when the lock-up clutch 25 should take the lock-up release state, the supply of the drive signal Ca to the lock-up control solenoid valve 11 is stopped,
The lock-up control solenoid valve 11 is closed, and the pressure control solenoid valve 12 is supplied with a drive signal Cb formed as a pulse signal having a pulse occupancy of less than a predetermined value, for example, less than 20%. , Pressure regulating solenoid valve 12
Are substantially closed. Accordingly, the oil pressure from the constant pressure forming part 31 connected to the oil pump 30 is supplied to the port h of the lock-up shift valve 50 through the common oil passage 47 and the oil passage 40 as it is or slightly reduced. In addition, the hydraulic pressure from the constant pressure forming unit 31 is applied to the common oil passage 47 and the oil passage 39 to the port d of the lock-up shift valve 50 and the port n of the lock-up pressure regulating valve 60, respectively.
Supplied through. On the other hand, the port a of the lock-up shift valve 50 is constantly supplied with the hydraulic pressure from the constant pressure forming unit 31 through the common oil passage 47 and the oil passage 38.

In the lock-up shift valve 50, since the pressure receiving area of the land portion 52b receiving the action of the hydraulic pressure supplied to the port h is larger than the pressure receiving area of the other lands in the lock-up shift valve 50, the port h The spool 52 is moved toward the spool 51 along with the urging force of the spring 53 of the spool 51 by the hydraulic pressure from the constant pressure forming part 31 supplied to the spool 51. , The port b and the port c are in communication with each other, and the port e and the port f are in communication with each other. Further, in the lock-up pressure regulating valve 60, the hydraulic pressure supplied to the port n causes the spool 61 to move against the urging force of the spring 62, and the spool 61 is moved to the position shown by the solid line in FIG. It is assumed that the port k and the port 1 are in communication with each other. Accordingly, the oil pressure regulated by the regulator valve 32 is transmitted through the common oil passage 49, the oil passage 44, the ports 1 and k of the lock-up pressure regulating valve 60, the oil passage 41, and the ports b and c of the lock-up shift valve 50. 35
And is supplied from the oil passage 35 to the back pressure chamber 27 of the torque converter 10 as working oil pressure, so that the working oil pressure in the back pressure chamber 27 is increased, and the working oil pressure in the inner pressure chamber 28 of the torque converter 10 is increased. The oil passage 36 is guided to the oil passage 42 through the ports e and f of the lock-up shift valve 50, and is discharged from the oil passage 42 to the oil cooler 33 so that the internal pressure chamber
The working oil pressure in the pressure chamber 28 is reduced, as a result
Although the value of the operating oil pressure in the internal pressure chamber 28 is larger than the value of the operating oil pressure in the lock-up clutch 25, the difference becomes less than a predetermined value, and the lock-up clutch 25 takes a position away from the drive plate 16 to lock up. It is in the release state.

Further, when the lock-up clutch 25 in the lock-up release state is to be in the slip engagement state, the drive signal Ca determined to have a predetermined level at the lock-up control solenoid valve 11 is output. The drive is supplied, the lock-up control solenoid valve 11 is opened, and the pressure control solenoid valve 12 is provided with a drive signal formed as a pulse signal within a predetermined range of the pulse occupancy, for example, 20 to 80%. The pulse signal Cb is supplied, and the pressure regulating solenoid valve 12 is opened during a period corresponding to the pulse width of the drive pulse signal Cb. As a result, the hydraulic pressure through the oil passage 40 is reduced by the lock-up control solenoid valve 11.
The hydraulic pressure is reduced from the port h of the lock-up shift valve 50, and the hydraulic pressure through the common oil passage 47 and the oil passage 39 increases the pulse occupancy of the drive signal Cb supplied to the pressure regulating solenoid valve 12. And supplied to the port d of the lock-up shift valve 50 and the port n of the lock-up pressure regulating valve 60, respectively.

In the lock-up shift valve 50, the hydraulic pressure reduced according to the increase of the pulse occupancy of the drive signal Cb is supplied to the port d. The pressure receiving area of the land portion 51a formed thereon is larger than the pressure receiving area of the other land portions of the spool 51 so as to be pressed against the pressure due to the sum of the hydraulic pressure supplied to the a and the biasing force of the spring 53. And the spool 51 is moved to the first position.
The spool 52 is to maintain the position as shown by the solid line in the figure, whereas the spool 52 is pressed by the hydraulic pressure supplied to the port d to assume the position as shown by the dashed line in FIG. It is said. Thereby, the communication state between the port c and the port b is maintained, but the communication state between the port e and the port f is switched from the communication state with the port f to the port g. On the other hand, lock-up pressure regulating valve
In 60, the spool 61 is connected to the port n by the pressure of the sum of the hydraulic pressure supplied to the port m from the regulator valve 32 through the common oil passage 49 and the passage 45 and the urging force of the spring 62.
Is moved to the port n side with a distance corresponding to the reduced pressure between the hydraulic pressure supplied to the port n and takes a position as shown by a dashed line in FIG. The area is reduced.

Therefore, the pressure is regulated by the regulator valve 32 and the common oil passage
49, oil passage 44, ports 1 and k of lock-up pressure regulating valve 60, oil passage
41, the oil pressure guided to the oil passage 35 through the ports b and c of the lock-up shift valve 50 and supplied from the oil passage 35 to the back pressure chamber 27 of the torque converter 10 is applied to the port 1 of the lock-up pressure regulating valve 60. The working oil pressure in the back pressure chamber 27 is reduced, and the oil pressure adjusted by the regulator valve 32 is directly used as the common oil passage 49, the oil passage 43. , Is guided to the oil passage 36 through the ports g and e of the lock-up shift valve 50, and from the oil passage 36 to the internal pressure chamber 28 of the torque converter 10.
Is supplied to the internal pressure chamber 28 to increase the operating oil pressure. As a result, the value of the operating oil pressure in the internal pressure chamber 28 is equal to or greater than the value of the operating oil pressure in the back pressure chamber 27 and the difference is within a predetermined range, and the lock-up clutch 25 is connected to the pump impeller 17 and the turbine runner. Internal pressure chamber between 18
It is in a slip fastening state in which a rotational speed difference corresponding to a pressure difference between the working oil pressure in the back pressure chamber 27 and the working oil pressure in the back pressure chamber 27 is generated.

When the lock-up clutch 25 is in the spring-engaged state in this manner, the torque converter
The differential pressure between the operating oil pressure in the back pressure chamber 27 and the operating oil pressure in the internal pressure chamber 28 in 10 is controlled by performing feedback control on the pulse occupancy of the drive signal Cb based on the differential pressure. Slip control is performed.

Further, as in the case where the engine 1 is accelerated while the slip control in the torque converter 10 is performed, the lock-up clutch placed in the slip engagement state is used.
When the lock-up clutch should be engaged by 25, the lock-up control solenoid valve
A drive signal having a predetermined level for 11
Supply of Ca is continuously performed, while the lock-up control solenoid valve 11 is maintained in the open state, and the pressure occupancy of the pressure regulating solenoid valve 12 is larger than a predetermined value, for example,
Drive signal formed as a pulse signal to be greater than 80%
Cb is supplied, and the pressure regulating solenoid valve 12 is opened in a period corresponding to the pulse width of the drive pulse signal Cb, and is therefore in the fully opened state or an opened state close to the fully opened state. As a result, the port h in the lock-up shift valve 50 through the lock-up control solenoid valve 11
And the oil pressure through the common oil passage 47 and the oil passage 39 is reduced by the pressure regulating solenoid valve 12,
It is extremely low and is supplied to each of the port d of the lock-up shift valve 5 and the port n of the lock-up pressure regulating valve 60.

In the lock-up shift valve 50, when the extremely low hydraulic pressure is supplied to the port d, the spool 51 is moved to the spool 52 side by the urging force of the spring 53, and presses the spool 52. , The spools 51 and 52 are in the positions shown by the dashed lines in FIG. 1, and the communication state between the port e and the port g is maintained, but the communication state between the port c and the port b is maintained. Is switched to the communication state with the drain port. On the other hand, in the lock-up pressure regulating valve 60, when the extremely low hydraulic pressure is supplied to the port n, the spool 61 is moved to the port n side by the urging force of the spring 62, and two points in FIG. Port k is assumed to be in the position shown by the dashed line.
And port l are cut off. Accordingly, the state in which the hydraulic pressure regulated by the regulator valve 32 is supplied to the internal pressure chamber 28 of the torque converter 10 as it is, and the internal pressure chamber is maintained.
The operating oil pressure in the pressure converter 28 is increased, while the back pressure chamber 27 of the torque converter 10 is provided with a regulator valve.
The supply of the regulated hydraulic pressure from 32 is stopped,
The hydraulic pressure in the oil passage 35 connected thereto is released through the port c of the lock-up shift valve 50 and the drain port connected thereto, so that the operating oil pressure in the internal pressure chamber 28 and the operating oil pressure in the back pressure chamber 27 are reduced. , The internal pressure chamber 28 in which the lock-up clutch 25 is in a slip-engaged state.
The operating oil pressure in the internal pressure chamber 28 is changed from the state where the operating oil pressure in the internal pressure chamber 28 is higher than the operating oil pressure in the back pressure chamber 27 by a value within a predetermined range.
Is directly changed to a state higher than the operating oil pressure by a predetermined value, and as a result, the lock-up clutch
25 is frictionally engaged with the drive plate 16 and is in a locked-up fastening state.

The lock-up release state, the slip engagement state, and the lock-up engagement state as described above are changed to a lock-up clutch.
The differential pressure Δ between the working oil pressure in the back pressure chamber 27 and the working oil pressure in the internal pressure chamber 28 in the torque converter 10 selectively taken by the torque converter 25
The relationship between P and the pulse occupancy DY of the drive signal Cb, which is a pulse signal supplied to the pressure regulating solenoid valve 12, is as shown in FIG. 3, for example. When the relationship shown in FIG. 3 is set, when the pulse occupation ratio DY takes a value less than the predetermined value d1, the differential pressure Δ
P is assumed to be a value less than the predetermined value P1, and therefore, the value of the operating oil pressure in the internal pressure chamber 28 is equal to or greater than the value of the operating oil pressure in the back pressure chamber 27, but the difference is less than the predetermined value P1. In this state, the lock-up clutch 25 is in the lock-up release state, and
When the pulse occupancy DY takes a value equal to or more than the predetermined value d1 and less than the predetermined value d2, the differential pressure ΔP is assumed to take a value equal to or more than the predetermined value P1 and up to the predetermined value P2, and therefore, the internal pressure The value of the operating oil pressure in the chamber 28 is equal to or greater than the value of the operating oil pressure in the back pressure chamber 27, and the difference increases in proportion to the pulse occupancy DY from a predetermined value P1 to a predetermined value P2. In this state, the lock-up clutch 25 is assumed to be in the slip-engaged state. Further, when the pulse occupancy D takes a value equal to or more than the predetermined value d2, the differential pressure ΔP Takes a predetermined value P3 which is larger than the predetermined value P2. Therefore, the state in which the value of the operating oil pressure in the internal pressure chamber 28 is larger than the value of the operating oil pressure in the back pressure chamber 27 by the predetermined value P In this state, the lock-up clutch 25 is in the lock-up engagement state.

If the relationship between the differential pressure ΔP and the pulse occupancy DY is as shown in FIG.
When the lockup clutch 25 is shifted from the slip engagement state to the lockup engagement state, the differential pressure ΔP temporarily assumes a value less than the predetermined value P1 in the process, and the lockup clutch 25 shifts the lockup release state. This is not to be expected, and therefore, the engine 1 is prevented from generating an undesired blow-up. The relationship between the differential pressure ΔP and the pulse occupancy DY as shown in FIG.
An oil passage 39 provided with the pressure regulating solenoid valve 12 is connected to a port d of the lock-up shift valve 50 in which the serially arranged spool 51 is located between the spool 51 and the constant pressure forming section 31. The oil passage 38 that constantly supplies the hydraulic pressure from the
The oil passage 40, which is connected to the port a positioned on the other end of the lock-up shift solenoid valve 11, is located on the other end of the spool 52 in the lock-up shift valve 50. This is obtained by adopting an oil passage configuration connected to the assigned port h.

(Effects of the Invention) As is apparent from the above description, according to the fluid coupling fastening force control device of the present invention, an input element such as a pump impeller, an output element such as a turbine runner, and a lock-up clutch are provided. In shifting the lock-up clutch in the fluid coupling from the slip engagement state to the lock-up engagement state, the first hydraulic passage is used to cause the lock-up clutch to assume the lock-up engagement state in which the input element and the output element are engaged. A first spool for supplying the hydraulic pressure, and a second spool for supplying the hydraulic pressure through the second hydraulic passage to cause the lock-up clutch to assume a lock-up release state in which the input element and the output element are disengaged. Two spools are arranged in series, and one end of a first spool and one end of a second spool opposed thereto. A shift valve in which the first hydraulic pressure acts on the other end, the second hydraulic pressure acts on the other end of the first spool, and the reference hydraulic pressure acts on the other end of the second spool. And a pressure regulating valve having a third spool that adjusts the operating oil pressure in the second oil pressure passage by the first and third oil pressures, and the first and second oil pressures are respectively set to the first and second oil pressures. The third hydraulic pressure is transmitted from the hydraulic pressure transmitting means while being controlled by the second hydraulic pressure control means, so that the shift valve acts on the lock-up clutch through the first and second hydraulic passages, respectively. Operating pressure can be directly changed from a state having a mutual difference required for the slip fastening state to a state having a mutual difference required for the larger lock-up fastening state. Therefore, the transition from the slip engagement state to the lock-up engagement state of the lock-up clutch in the fluid coupling is performed, for example, once in the first and second oil chambers provided for the lock-up clutch, respectively. In this case, the difference between the operating hydraulic pressures applied through the second hydraulic passage is substantially reduced to zero, so that the lock-up release state can be achieved without going through the lock-up release state. When the engine to which the fluid coupling is connected is accelerated under the state, undesired blowing of the engine can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of a fastening force control device of a fluid coupling according to the present invention, and FIG. 2 shows an example of a fastening force control device of a fluid coupling according to the present invention together with a power plant to which it is applied. FIG. 3 and FIG. 3 are characteristic diagrams used to explain the operation in the example shown in FIG. In the figure, 2 is an automatic transmission, 10 is a torque converter, 11 is a solenoid valve for lock-up control, 12 is a solenoid valve for pressure regulation, 15 is a hydraulic circuit, 16 is a drive plate, 17 is a pump impeller, and 18 is a turbine runner. , 25 is a lock-up clutch, 27 is a back pressure chamber, 28 is an internal pressure chamber, 50 is a lock-up shift valve, 51 and 52 are spools of the lock-up shift valve 50, 60 is a lock-up pressure regulating valve, 70 is a control unit, a ,
d and h are ports of the lock-up shift valve 50.

Claims (1)

(57) [Claims] 1. A slip fastening state in which, in addition to an input element and an output element connected to an output shaft of an engine mounted on a vehicle, the input element and the output element are engaged in a relatively rotatable state. In order to cause the lock-up clutch in the fluid coupling having a lock-up clutch to perform an operation of bringing the input element and the output element into an engaged state, a first oil chamber provided for the lock-up clutch is provided. A first hydraulic passage for applying a hydraulic pressure, and a second hydraulic passage provided to the lock-up clutch so as to cause the lock-up clutch to perform an operation of disengaging the input element and the output element. A second hydraulic passage for applying an operating hydraulic pressure to the oil chamber, a hydraulic circuit portion having the first and second hydraulic passages, and a first hydraulic circuit provided in the hydraulic circuit portion and arranged in series. The second
And a first hydraulic pressure acts between one end of the first spool and one end of the second spool facing the one end of the first spool. A second hydraulic pressure acting on the other end of the first spool, and a reference hydraulic pressure acting on the other end of the second spool; and a second valve via the shift valve. A third spool that is connected to the first hydraulic pressure and that is acted on by the first hydraulic pressure, and that adjusts a hydraulic pressure that adjusts a working hydraulic pressure in the second hydraulic pressure passage; A first oil pressure control means for controlling the first oil pressure, a second oil pressure control means for controlling the second oil pressure in accordance with an operation state of the vehicle, and performing the oil pressure adjustment on the pressure regulating valve Third to act
And a hydraulic pressure transmitting means for transmitting the hydraulic pressure of the first hydraulic pump. The first spool is configured to discharge a working hydraulic pressure from the first hydraulic passage in accordance with the first and second hydraulic pressures. The position where the supply of hydraulic oil to the first hydraulic passage is performed is selectively taken, and the second spool is connected to the position where the supply of hydraulic oil to the second hydraulic passage is performed. And a position at which the operating oil pressure is discharged from the hydraulic passage of the second hydraulic passage. The third spool controls the operating oil pressure in the second hydraulic passage in accordance with the first and third oil pressures. A fastening force control device for a fluid coupling, wherein a position for increasing and a position for decreasing are selectively selected.