JPH044355A - Engaging force control device for fluid coupling - Google Patents

Abstract

PURPOSE:To avoid undesirable increasing in revolution by employing a shift valve which allows first hydraulic pressure to be applied to a space between one end section of a first spool and one end section of a second spool opposite to the first one, concurrently allows second hydraulic pressure to be applied to the other end section of the first spool, and also allows reference hydraulic pressure to be applied to the other end of the second spool. CONSTITUTION:Working hydraulic pressure which is applied to a lock-up clutch 25 from a shift valve 50 including 2 spools 51 and 52 through a first and second hydraulic passage, is directly changed from a condition keeping the mutual difference required to hold a slip engaging condition over to a condition keeping the mutual difference greater than the aforesaid one required to hold a lock-up engaging condition. By this constitution, the movement of the lock-up clutch 25 from the slip condition to the lock-up engaging condition can thereby be made with no passing made through a lock-up releasing condition. As a result, when an engine to which a fluid coupling is connected with the clutch 25 kept in a slipt engaging condition, is accelerated, an undesirable increase in revolution can be avoided.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a human power element such as a pump impeller, an output element such as a turbine runner, and a fluid that controls the operation of a lock-up clutch in a fluid coupling equipped with a lock-up clutch. The present invention relates to a fastening force control device for a joint.

(Prior Art) A fluid coupling provided in an automatic transmission mounted on a vehicle, as a so-called hydraulic torque converter, includes a pump impeller that constitutes an input element connected to the output shaft of an engine, and a turbine that constitutes an output element. It is known that in addition to the runner, a lock-up clutch is provided to mechanically connect the pump impeller and the turbine runner. In a hydraulic torque converter equipped with such a lock-up clutch, the lock-up clutch acts as a 1-lux converter when torque is transmitted from the engine to the wheel drive system via the automatic transmission. In order to reduce energy loss, the input part connected to the pump impeller is engaged in a lock-up state in which the pump impeller and the turbine runner are directly connected by frictional engagement. A lock-up release state in which the pump impeller and turbine runner are not engaged with each other by being located at a distance from the input part, and furthermore, reduction of energy loss in the l~rconharter even when the vehicle is in a particular driving state. In order to achieve both this and the reduction of vehicle body vibration, the system selectively creates a slip engagement state in which the pump impeller and the turbine runner are frictionally engaged with the input section connected to the pump impeller, creating a rotational speed difference between the pump impeller and the turbine runner. It is considered to be taken.

The operation of such a lock-up clutch is, for example, as shown in Japanese Unexamined Patent Publication No. 62-297567.
By supplying working oil pressure from the hydraulic circuit section in a predetermined manner to the two chambers that sandwich the lock-up clutch, the hydraulic pressure is adjusted according to the difference in working oil pressure that occurs between the two chambers that sandwich the lock-up clutch. It is done as a thing. A hydraulic circuit section that supplies hydraulic pressure to the lock-up clutch usually includes a shift valve 1 to a valve that supplies and discharges hydraulic pressure to each of two chambers provided between the lock-up clutches, and A pressure regulating valve is provided in one of the two chambers sandwiching the lock-up clutch through the shift I valve to adjust the hydraulic pressure supplied to the lock-up clutch in order to release the lock-up state, and the shift valve The hydraulic pressure supplied to each of the two chambers provided for the lock-up clutch is controlled according to the operating mode that the pressure regulating valve takes when the hydraulic pressure that is applied to each of the pressure regulating valves is changed.

(Problems to be Solved by the Invention) Torque is provided with a lock-up clutch whose operation is controlled by hydraulic pressure that is controlled according to the operation mode of the shift valve and pressure regulating valve provided in the hydraulic circuit section as described above. The converter is designed to reduce both energy loss and vehicle body vibration when transmitting torque from the pump impeller to the turbine runner under vehicle running conditions that satisfy predetermined conditions such as engine load and vehicle speed. In order to achieve this, slip control is performed in which the lock-up clutch is placed in a slip-engaged state and a difference in rotational speed is created between the pump impeller and the turbine runner. When the engine is to be accelerated, the six lock-up clutches in the 1-lux converter converter are changed from a slip engagement state to a lock-up engagement state. Then, the control for shifting the lock-up clutch from the slip engagement state to the lock-up engagement state is performed by changing the oil pressure that is supposed to act on the shift valve and the pressure regulating valve, and as a result, the two The hydraulic pressure is supplied and discharged to and from the two chambers, and in this case, one of the two chambers, which is provided between the lock-up clutch and the lock-up clutch, is controlled to release the lock-up state through the shift valve. Hydraulic pressure that acts on a pressure regulating valve that adjusts the hydraulic pressure supplied as much as possible;
The other of the two chambers provided between the lock-up clutch is supplied with the hydraulic pressure that acts on the shift valve to control the hydraulic pressure that is supplied to the lock-up clutch to bring it into the lock-up state. The lock-up clutch in the torque converter is provided between the lock-up clutch and the lock-up clutch in the process of shifting the lock-up clutch from the slip engagement state to the lock-up engagement state. A situation occurs in which the working oil pressure difference between the two chambers is temporarily reduced to zero, and as a result, the lock-up clutch is temporarily released from the lock-up state, causing the engine to rev up. There is an IL< that can lead to undesirable situations.

In view of the above, the present invention provides a method for transitioning an input element such as a pump impeller, an output element such as a turbine runner, and a lock-up clutch in a fluid coupling equipped with a lock-up clutch from a slip engagement state to a lock-up engagement state. , in the process, it is possible to avoid a situation in which the lock-up clutch - sometimes assumes a lock-up release state with undesired engine revving of the engine to which the fluid coupling is connected. The object of the present invention is to provide a fastening force control device.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, a fastening force control device for a fluid coupling according to the present invention has an input element, an output element, and a state in which the input element and the output element can be relatively rotated. Hydraulic pressure and input for causing an operation to bring an input element and an output element into a locked state in a fluid coupling having a one-way pull-up clutch that can be engaged in a slip engagement state. a hydraulic circuit section having first and second hydraulic pressure passages for respectively applying hydraulic pressure for disengaging the element and the output element; and a first hydraulic circuit section provided in the hydraulic circuit section;
A shift valve includes a first spool that supplies and discharges working hydraulic pressure to and from a hydraulic passage, and a second spool that supplies and discharges working hydraulic pressure to and from a second hydraulic passage, which are arranged in series; a pressure regulating valve that is connected to a hydraulic passage of the first spool and adjusts the working oil pressure in the second hydraulic passage, and the shift valve is connected to one end of the first spool and a second
A first hydraulic pressure acts on one end of the spool, a second hydraulic pressure acts on the other end of the first spool, and a reference oil pressure acts on the other end of the second spool. a first hydraulic control means for controlling the first hydraulic pressure; a second hydraulic control means for controlling the second hydraulic pressure;
Further, a third hydraulic pressure control means is provided and configured to control the hydraulic pressure that acts on the pressure regulating valve to adjust the hydraulic pressure.

(Function) In the fluid coupling fastening force control device according to the present invention configured as described above, the shift valve brings the input element and the output element into engagement with the lock-up clutch in the fluid coupling. The first spool supplies hydraulic pressure to the lock-up clutch and the human power element and the output element are disengaged so that the lock-up engagement state is achieved! =1 A second spool for supplying and discharging hydraulic pressure in order to release the pull-up state is arranged in series, and between one end of the first spool and one end of the second spool opposing it. The first hydraulic pressure acts on the other end of the first spool, the second hydraulic pressure acts on the other end of the first spool, and the reference oil pressure acts on the other end of the second spool. In transitioning the up clutch from a slip engagement state in which the input element and the output element are engaged in a relatively rotatable state to a lockup engagement state, the first and second hydraulic pressures are controlled by the first and second hydraulic pressure control means, respectively. Under the control, the hydraulic pressure applied from the shift valve to the lock-up clutch through the first and second hydraulic passages, respectively, is changed from a state having a mutual difference required for a sliding engagement state to a state having a mutual difference required for a sliding engagement state to a state greater than that. This means that it is possible to directly change the state having the mutual difference required for the lock-up engaged state.

Therefore, the transition from the slip engagement state to the lock-up engagement state for the lock amplifier clutch in the fluid coupling may occur, for example, when the lock-up clutch is first applied to the lock-up clutch.
The difference between the hydraulic pressure applied through the first and second hydraulic passages is made substantially zero, and the lock-up clutch in the fluid coupling is released without going through a situation where the lock-up release state is taken. When the engine connected to the fluid coupling which is in the slip engagement state is accelerated, it is possible to avoid undesired engine revving.

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

The power plan 1- shown in FIG. 2 consists of an engine 1 and an automatic transmission 2. The engine 1 has, for example, four cylinders, and each of the four cylinders has the following: A mixture formed by intake air from an intake passage 5 in which a throttle valve 4 is disposed and fuel injected from a fuel injection valve disposed in the intake passage 5 is supplied, and the mixture is ignited in each cylinder. It is burned by the operation of the system and discharged into 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 that includes the automatic transmission 2.

The automatic transmission 2 includes a multi-gear type transmission mechanism 9, a fluid type 1-luke converter 10 which is a fluid coupling, a lock-up control solenoid valve 11 that forms and supplies hydraulic pressure used for controlling these components, and Pressure regulating solenoid valve 12
The hydraulic circuit section 15 is equipped with various solenoid valves, shift valves, and the like.

The transmission mechanism 9 is equipped with various frictional engagement elements such as a planetary gear section, a clutch, and a brake to obtain, for example, four forward speeds and one reverse speed. Hydraulic pressure and release oil pressure are selectively supplied as appropriate from the hydraulic circuit section 15 via various control valves or shift valves provided therein. As a result, each frictional engagement element is brought into a engaged state or a released state, and each of the drive range, 2 range, and lunge range, which constitute the parking range, reverse range, neutral range, and forward range, and the forward It is possible to obtain the first to fourth gears in the range.

In FIG. 1, the torque converter 10 is involved in controlling the operation of the torque converter 10 in a hydraulic circuit section 15 that includes an oil pump 30, a constant pressure forming section 31, and a regulator valve 32 connected to the oil pump 30, respectively. As shown in FIG. Pump impeller 17° connected to drive plate 16 and rotating therewith; Turbine runner 18 to which torque generated by engine 1 is transmitted via pump impeller 17 and hydraulic oil. It includes a stator 19 disposed between the pump impeller 17 and the turbine runner 187, and a one-way clutch 2° disposed between the stator 19 and a fixed part of the torque converter 10, and further includes a stator 19 disposed between the pump impeller 17 and the turbine runner 187, and a one-way clutch 2° disposed between the stator 19 and a fixed part of the torque converter 10. A one-to-one shock damper 22 is disposed between the runner 18 and spline-fitted to the turbine hub 21, and a lock-up clutch 25 is connected to the torsion damper 22 via a coil spring 23. be done. The lock-up clutch 25 is arranged so that its entirety approaches and separates from the drive plate 16, and rotates 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 interposed between the drive plate 16 and the turbine runner 18 in the torque converter 10, so that a back pressure chamber 27 and
An internal pressure chamber 28 is formed, and the back pressure chamber 27 is supplied with working hydraulic pressure to press the lock-up clutch 25 in a direction to separate it from the drive plate 16 through an oil passage 35 in the hydraulic circuit section 15. In room 28,
Hydraulic pressure is supplied through the oil passage 36 in the hydraulic circuit section 15 to press the lock-up clutch 25 in a direction toward the drive plate 16. When the working oil pressure in the internal pressure chamber 28 is higher than the working oil pressure in the back pressure chamber 27 by a predetermined value or more, the lock-up clutch 25 is pushed to the right in FIG. A lock-up state is achieved in which the pump impeller 17 and the turbine runner 18 are engaged by friction, and the value of the working oil pressure in the internal pressure chamber 28 is greater than or equal to the value of the working oil pressure in the back pressure chamber 27. However, when the difference is less than a predetermined value, the pump impeller 17 and the turbine runner are pushed to the left in FIG. A lock-up release state is assumed in which the lock-up is disengaged. Furthermore, when the value of the working oil pressure in the internal pressure chamber 28 is greater than or equal to the value of the working oil pressure in the back pressure chamber 27 and the difference is within a predetermined range, the lock-up clutch 25 is activated between the pump impeller 17 and the turbine runner 18. The drive plates 16 and 16 are engaged in a relatively rotatable state, and the slip rate with respect to the drive plates 1 and 16 becomes smaller as the differential pressure increases. is being used. In addition, internal pressure chamber 2
8 is connected to an oil cooler 33 through an oil passage 37 in which a check valve 29 is disposed.

A portion of the hydraulic circuit section 15 that is involved in controlling the operation of the torque converter 10 includes a lock-up shift valve 50. Lock-up pressure regulating valve 60. A solenoid valve 11 for lock-up control and a solenoid valve 12 for pressure regulation are provided.

The lock-up shift valve 50 is composed of two spools 51 and 52 arranged in series, and has bows 1-a-h that are opened and closed by the spools 51 and 52, and three drain ports. spring 5
3, it is urged toward the spool 52 side. The spools 51 and 52 of the lock amplifier shift valve 50 are provided with a land portion 51a and a land portion 52a, respectively, on one end side facing each other, and further,
The spool 51 is provided with a land portion 51b on the other end side, and a land portion 51c is provided between the land portion 51a and the land portion 51b.
The pressure receiving area of a is larger than the pressure receiving area of the land portions 51b and 51c. Further, the spool 52 is also provided with a land portion 52b on the other end side, and a land portion 52c is provided between the land portion 52a and the land portion 52b, and the pressure receiving area of the land portion 52b is
The pressure receiving area of the land portion 51a in the spool 51 is larger than the pressure receiving area of the land portion 51a in the spool 51, and the pressure receiving area of the land portions 52a and 52c is made equal to the pressure receiving area of the land portion 51a in the spool 51. The port a is located on the other end side of the spool 51, and the port d is located on the spool 51 facing each other.
and 52, and further includes:
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 that is biased toward the other end by a spring 62. It has a boat t-j-n that is opened and closed by a spool 61, and three drain boats, and the spool 61 has a land portion 61a.
, 61b and 61c are provided.

In the lock-up shift valve 50, the ball l
-a passes through the oil passage 38, and port d passes through the oil passage 39 in which the pressure regulating solenoid valve 12 is provided.
The port h is connected to the common oil passage 47 extending from the constant pressure forming part 31 through the oil passage 40 in which the solenoid valve 11 for the lock-up control part is provided, and the port b is connected to the bow 1-j of the lock-up pressure regulating valve 60 through the oil passage 41. and k, port C is connected to the back pressure chamber 27 through the oil passage 35, and e is connected to the back pressure chamber 27 through the oil passage 48 and the 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 regulating valve 60, the port! is connected to the common oil passage 49 extending from the regulator valve 32 through the oil passage 44 and through the port m or oil passage 45, and the port n is connected through the oil passage 46 to the part of the oil passage 39 where the pressure regulating solenoid valve 12 is provided. Connected to the downstream side.

Note that orifices are provided at predetermined positions in each of the oil passages 36, 3B, 39, 40, 41, and 46.

A lock-up control solenoid valve 11 provided in the oil passage 40 and a pressure regulating solenoid valve 12 provided in the oil passage 39
The operation of each of them is controlled by a control unit 70. As shown in FIG. 2, the control unit 70 includes, for example, a throttle opening sensor 5 that detects the opening of the throttle valve 4.
5. A rotation speed sensor 56 that detects the engine rotation speed. Based on various detection output signals obtained from a vehicle speed sensor 57 that detects the running speed of the vehicle and a sensor group 58 that detects other running conditions of the vehicle, the lock-up control solenoid valve 11 and adjustment provided in the hydraulic circuit section 15 are activated. It supplies drive signals Ca and drive signals cb to the pressure solenoid valves 12, respectively, and supplies a drive signal group Cc to various solenoid valves provided for control valves and shift valves arranged in relation to the transmission mechanism 9. control their operations. Thereby,
1 - Operation control of the lock-up clutch 25 in the torque converter 10 and speed change control of the transmission mechanism 9 are performed.

When controlling the operation of the lock-up clutch 25 by the control unit 70, the control unit 70 determines whether the lock-up clutch 25 is in a lock-up release state, a slip engagement state, or a lock-up state based on various detection output signals supplied thereto. It is determined which of the fastened states should be taken.

For example, when the lock-up clutch 25 should be in 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 regulating solenoid valve 11 is closed. A drive signal cb formed as a pulse signal that makes the pulse occupancy less than a predetermined value, for example less than 20%, is supplied to the solenoid valve 12, and the pressure regulating solenoid valve 12 is brought into a substantially closed state. As a result, the oil pressure from the constant pressure forming part 31 connected to the oil pump 30 is applied to the boat h in the lock-up shift valve 50 through the common oil passage 47 and the oil passage 40, or as it is.
The constant pressure forming portion 31 is supplied to the boat d in the lock-up shift valve 50 and the ports 1-n in the lock-up pressure regulating valve 60, respectively.
Hydraulic pressure is supplied from the common oil passage 47 and the oil passage 39. On the other hand, the bow 1 in the lock-up shift valve 50
~a are always supplied with hydraulic pressure from the constant pressure forming section 31 through the common oil passage 47 and the oil passage 38.

In the lock-up shift valve 50, the pressure-receiving area of the land portion 52b that receives the action of the hydraulic pressure supplied to the bow 1-h is larger than the pressure-receiving area of the other land portions in the lock-up shift valve 50. The spring 53 of the spool 51 moves the spool 52 toward the spool 51 by the hydraulic pressure from the constant pressure forming part 31 supplied to the boat h.
The spools 51 and 52 are moved as shown by the solid line in FIG. At the same time, boat C and boat 1-f are brought into communication. Further, in the lock-up pressure regulating valve 60, the spool 61 is moved by the hydraulic pressure supplied to the ports 1-n against the biasing force of the spring 62, and the spool 61 is moved to the position shown by the solid line in FIG. The port 1-ff is placed in communication with the boat. Therefore, the oil pressure regulated by the regulator valve 32 is applied to the common oil path 4.
9. Boat with oil line 44 and lock-up pressure regulating valve 60! and k.

Oil road 41. It is led to the oil passage 35 through the boats b and C of the lock-up shift valve 5'0, and is supplied from the oil passage 35 to the back pressure chamber 27 in the torque converter 10 as working oil pressure, increasing the working oil pressure in the back pressure chamber 27. At the same time, the internal pressure chamber 2B in the torque converter 10
The hydraulic pressure in the oil passage 36. Lock-up shift valve 50
The boats e and [ are guided to the oil passage 42 through the oil passage 42
is discharged to the oil cooler 33 and the working oil pressure in the internal pressure chamber 28 is reduced, and as a result, the working oil pressure in the internal pressure chamber 28 is made larger than the working oil pressure in the back pressure chamber 27. When the difference becomes less than a predetermined value, the lock-up clutch 25 is placed in a lock-up release state in which it assumes a position away from the drive plate 1-16.

In addition, when the lock-up clutch 25 in the lock-up release state is set to a slip-engaged state, the lock-up control solenoid valve 11
A drive signal Ca having a predetermined level is supplied to (1) so that the cock-up control solenoid valve 11 is opened, and the pressure regulating solenoid valve 12 is supplied with a pulse occupancy rate within a predetermined range. For example, the drive pulse signal cb formed as a pulse signal of 20 to 80% is supplied, and the pressure regulating solenoid valve 12 is activated by the drive pulse signal c.
It is in an open state during a period corresponding to the pulse width of b. As a result, the oil pressure passing through the oil passage 40 is reduced through the lock-up control solenoid valve 11, the oil pressure is removed from the port h of the lock-up shift valve 50, and the oil pressure passing through the common oil passage 47 and the oil passage 39 is reduced.
The higher the pulse occupancy rate of the drive signal cb supplied to the pressure regulating solenoid valve 12, the lower the value.
It is supplied to each of the ports 1-d which go to the lock-up shift valve 50 and the port n of the lock-up pressure regulating valve 60.

In the lock-up shift valve 50, the oil pressure is reduced in response to an increase in the pulse occupancy rate of the drive signal cb.
d, but the spool 51 is pressed by the reduced hydraulic pressure supplied to the port d against the pressure due to the sum of the hydraulic pressure supplied to the bow 1-a and the biasing force of the spring 53. As shown in FIG.
The pressure receiving area of 1a is made larger than the pressure receiving area of the other runt parts of the spool 51, and thereby,
The spool 51 is assumed to maintain the position shown by the solid line in FIG. It shall assume the position shown. As a result, baud 1-c and baud 1-b remain in communication, but baud 1-e is switched from communicating with port f to communicating with port g. On the other hand, in the lock-up pressure regulating valve 60,
The spool 61 is connected from the regulator valve 32 to the common oil passage 49.
and pressure due to the sum of the hydraulic pressure supplied to the port m through the passage 45 and the biasing force of the spring 62, and the bow 1-n.
It is moved to the port n side by a distance corresponding to the differential pressure between the reduced hydraulic pressure supplied to the port n, and takes a position as shown by the dashed line in FIG. The effective aperture area of is reduced.

Therefore, the pressure is regulated by the regulator valve 32, and the common oil passage 49. Oil road 44. Lockup pressure regulating valve 60 port! and oil passage 41. Port b of lock-up shift valve 50
and C to the oil passage 35 and supplied from the oil passage 35 to the back pressure chamber 27 in the torque converter 10 as working oil pressure, depending on the reduction in the effective opening area of the bow 1-ffi in the lock-up pressure regulating valve 60. As a result, the working oil pressure in the back pressure chamber 27 is reduced, and the oil pressure regulated by the regulator valve 32 continues to flow through the common oil passage 49. Oil road 43. The internal pressure chamber 2 in the torque converter 10 is led to the oil passage 36 through ports g and e of the lock-up shift valve 50, and from the oil passage 36
8 as working oil pressure, and the working oil pressure in the internal pressure chamber 28 is increased. As a result, the value of the working oil pressure in the internal pressure chamber 28 is greater than or equal to the value of the working 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. 18
A slip engagement state is established in which a difference in rotational speed is generated between the hydraulic pressure in the internal pressure chamber 28 and the hydraulic pressure in the back pressure chamber 27 in accordance with the differential pressure.

Note that when the lock-up clutch 25 is placed in the slip engagement state in this way, the torque converter 1
The differential pressure between the working hydraulic pressure in the back pressure chamber 27 and the working hydraulic pressure in the internal pressure chamber 28 at 0 is the drive signal c based on the differential pressure.
Slip control is performed by performing feedback control on the pulse occupancy rate of b.

Further, when the engine 1 is accelerated while the torque converter 10 is under slip control (
, the close-up clutch 2 is in a slip-engaged state.
5 should be in the lock-up clutch engagement state, the drive signal Ca having a predetermined level is continuously supplied to the lock-up control solenoid valve 11, and the lock-up control solenoid valve 11 is While the solenoid valve 11 is maintained in the open state, the pressure regulating solenoid valve 12 has a pulse occupancy rate greater than a predetermined value.
For example, the drive signal cb formed as a pulse signal larger than 80% is supplied, and the pressure regulating solenoid valve 12 is kept open during a period corresponding to the pulse width of the drive pulse signal cb, and is therefore kept fully open. Alternatively, it is set to an open state close to a fully open state. As a result, the hydraulic pressure is removed from the port h of the lock-up shift valve 50 through the lock-up control solenoid valve 11, and the hydraulic pressure flowing through the common oil passage 47 and the oil passage 39 is reduced by the pressure regulating solenoid valve 12, so that the oil pressure becomes extremely low. The output voltage is supplied to ports 1-d of the lock-up shift valve 50 and port n of the lock-up pressure regulating valve 60, respectively.

In the lockup shift I/valve 50, when extremely low oil pressure is supplied to the boat d, the spool 51 is moved toward the spool 52 by the biasing force of the spring 53 and presses the spool 52. As a result, the spools 51 and 52 are assumed to take positions as shown by the dashed lines in FIG.
Although the communication state between port e and ports 1-g is maintained,
Port 1-c is switched from communicating with boat b to communicating with the drain boat. On the other hand, in the lock-up pressure regulating valve 60, by supplying an extremely low hydraulic pressure to the port n, the spool 61 is moved toward the port n side by the biasing force of the spring 62, and as shown in FIG. The boat is assumed to be in the position shown by , and the boat and the boat L are cut off from each other. Therefore, the internal pressure chamber 2 of the torque converter 10
8, the hydraulic pressure regulated by the regulator valve 32 is maintained as it is, and the working hydraulic pressure in the internal pressure chamber 28 is increased. The supply of the regulated hydraulic pressure from the regulator valve 32 is stopped, and the hydraulic pressure in the oil passage 35 connected thereto is removed through the port 1-c of the lock-up shift valve 50 and the drain port communicated therewith. As a result, the working hydraulic pressure in the internal pressure chamber 28 and the working hydraulic pressure in the back pressure chamber 27 are changed so that the lock-up clutch 25 is put into the slipping state. The working oil pressure in the internal pressure chamber 28 is directly changed from a state higher than the working oil pressure by a value within a predetermined range to a state higher than the working oil pressure in the back pressure chamber 27 by a value exceeding the predetermined value, resulting in locking. The up clutch 25 is brought into frictional engagement with the drive plate 16 and placed in a lock-up engaged state.

The above-mentioned lock-up release state, slip engagement state, and lock-up engagement state are controlled by the lock-up clutch 2.
P to the differential pressure 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 which is selectively applied to the pressure P and the pulse signal supplied to the pressure regulating solenoid valve 12. The relationship between the drive signal cb and the pulse occupation rate DY is, for example, as shown in FIG.

When the relationship shown in FIG. 3 is set, when the pulse occupancy rate DY takes a value less than the predetermined value 41, the differential pressure P assumes a value less than the predetermined value 21. Therefore, the value of the working oil pressure in the internal pressure chamber 28 is equal to that in the back pressure chamber 2.
7, but the difference is the predetermined value 21
In such a state, the lock-up clutch 25 is considered to be in the lock-up released state, and the pulse occupation rate DY is equal to or greater than the predetermined value 61 and the predetermined value 42. When the pressure difference ΔP takes a value less than the predetermined value 21 and up to the predetermined value P2, the value of the working hydraulic pressure in the internal pressure chamber 28 is equal to the working pressure in the back pressure chamber 27. The pulse occupancy rate DY is equal to or greater than the value of the oil pressure, and the difference therebetween is from a predetermined value P1 to a predetermined value P2.
In this state, the lock-up clutch 25 is in a slipping engagement state, and furthermore, the pulse occupancy rate DY is a predetermined value of 62 or more. When taking the value, the differential pressure ΔP is assumed to take a predetermined value P3 that is smaller than the predetermined value P2,
Therefore, the value of the working oil pressure in the internal pressure chamber 28 is set to be larger than the value of the working oil pressure in the back pressure chamber 27 by a predetermined value P, and in such a state, the lock-up clutch 25 is engaged in the lock-up state. considered to be in a state of

Under the condition that the relationship between the differential pressure P and the pulse occupation rate DY is as shown in FIG. temporarily,
This prevents a situation in which the differential pressure P takes a value less than the predetermined value P1 and the lock-up clutch 25 assumes the lock-up release state, and therefore the engine 1 causes undesired engine revving. This will be avoided. The relationship between the differential pressure ΔP and the pulse occupation rate DY as shown in FIG.
is connected to the boat d located between the spool 51 and the spool 52 arranged in series in the lock-up shift valve 50, and is connected to the oil passage 38 which constantly supplies hydraulic pressure from the constant pressure forming part 31; An oil passage 4° connected to the port 1-a located on the other end side of the spool 51 in the lock-up shift valve 50 and provided with the lock-up control solenoid valve 11 is connected to the port 1-a located on the other end side of the spool 51 in the lock-up shift valve 50. This is achieved by employing an oil passage configuration that is connected to a port th located at the other end of the spool 52.

(Effects of the Invention) As is clear from the above description, the fluid coupling fastening force control device according to the present invention includes an input element such as a pump impeller, an output element such as a tahin runner, and a lock-up clutch. In order to shift the lock-up clutch in the fluid coupling from the slip engagement state to the lock-up engagement state, the lock-up clutch is operated through the first hydraulic passage in order 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 that supplies hydraulic pressure; and a second spool that supplies hydraulic pressure through a second hydraulic passage to cause the lock amplifier clutch to enter a lock-up release state in which the input element and the output element are disengaged. The spools are arranged in series, and a first hydraulic pressure is applied between one end of the first spool and the opposite end of the second spool, and a second hydraulic pressure is applied to the other end of the first spool. A shift valve is provided on which a reference oil pressure acts on the other end of the second spool, and the first and second oil pressures are applied to the first and second oil pressures, respectively.
The hydraulic pressures applied from the shift valve to the lock-up clutch through the first and second hydraulic passages have a mutual difference required for the slip engagement state. This allows for a direct change from one state to another with the differences required for a greater lock-up engagement 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 caused, for example, by the difference in the working oil pressures that are applied to the lock-up clutch through the first and second hydraulic passages, respectively. As a result, even if the lock-up clutch in the fluid coupling is in the slipping state, the engine connected to the fluid coupling can be Undesirable engine revving can be avoided when the engine is accelerated.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an example of a fluid coupling fastening force control device according to the present invention, and FIG. 2 is a schematic diagram of an example of a fluid coupling fastening force control device according to the present invention, and a power plant to which the same is applied. 3 is a characteristic diagram used to explain the operation in the example shown in FIG. 1. In the figure, 2 is an automatic transmission, 10 is a torque converter, and 11
is a solenoid valve for controlling the lock amplifier, 12 is a solenoid valve for pressure regulation, I5 is a hydraulic circuit section, 16 is a drive plate, 17 is a pump impeller, 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 port/amplifier shift valve 50, 60 is a lock-up pressure regulating valve, and 70 is a control unit 1- , a, d and h are the ports of the lock-up shift valve 50. Patent applicant Mazda Motor Corporation

Claims (1)

[Scope of Claims] The lock-up clutch in a fluid coupling having an input element, an output element, and a lock-up clutch that can take a slip engagement state in which the input element and the output element are engaged in a relatively rotatable state. a first and a first hydraulic pressure system for applying a hydraulic pressure for bringing the input element and the output element into an engaged state, and a working hydraulic pressure for bringing the input element and the output element into a disengaged state, respectively; a hydraulic circuit section having two hydraulic passages; a first spool provided in the hydraulic circuit section for supplying and discharging hydraulic pressure to the first hydraulic passage; and a first spool for supplying and discharging hydraulic pressure to the first hydraulic passage; A second spool for discharging is arranged in series and connects one end of the first spool with the first spool.
A first hydraulic pressure acts between one end of the spool and one end of the second spool opposing the second spool, and a second hydraulic pressure acts on the other end of the first spool, and a shift valve on which a reference hydraulic pressure acts on the other end of the second spool; and the shift valve is connected to the second hydraulic passage through the shift valve, and adjusts the working hydraulic pressure in the second hydraulic passage. a pressure regulating valve, a first hydraulic pressure control means for controlling the first hydraulic pressure, a second hydraulic pressure control means for controlling the second hydraulic pressure, and a hydraulic pressure that acts on the pressure regulating valve to adjust the hydraulic pressure. A fastening force control device for a fluid coupling, comprising: a third hydraulic control means for controlling.