JPH051755A - Oil pressure control device for continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent hunting of a mode change of an oil pump device against a change of the quantity of oil used on the torque converter side or the like securely in an oil pressure control system having a variable displacement type oil pump device as an oil pressure source. CONSTITUTION:In a variable displacement type oil pump device 40 for supplying the oil to a continuously variable transmission 5, a torque converter 12, a lock up clutch 15 or the like, an initial pressure circuit 58 of a switching solenoid valve 46 for changing the drive to the single mode or the twin mode and a release circuit 79 of the lock up clutch 15 are separated to eliminate the influence to each other. Even if a flow rate of oil used on the torque converter side is changed, hunting of a mode change of the oil pump device 40 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for a vehicle belt type continuously variable transmission provided with an oil pump device having a variable pump capacity, and more specifically, to an oil control system when lockup is OFF. Regarding hunting prevention measures for pump devices.

[0002]

2. Description of the Related Art Generally, in a continuously variable transmission equipped with a lock-up torque converter and a hydraulic forward / reverse switching device, a hydraulic control system of the continuously variable transmission includes a torque converter, a lock-up clutch, a forward / reverse switching device, and Is configured by combining a hydraulic system of a lubrication unit such as a belt. For this reason, the pump flow rate changes depending on the driving and running conditions, and the operating state of each transmission element also changes, resulting in a large change in the oil use flow rate. Therefore, in order to cope with such an oil usage state, there has been proposed one in which the oil pump device of the hydraulic source is configured to have a variable capacity.

[0003] Conventionally, as a variable displacement oil pump device provided in a hydraulic control device for a continuously variable transmission, there is, for example, the prior art of Japanese Patent Application No. 2-332120. Here, in the roller vane type oil pump, the main pump having one set of suction port and discharge port is always in communication with the load operation state, and the sub-pump having another set of suction port and discharge port is loaded or unloaded by the switching valve. Connect to enable load operation. Further, a hydraulic circuit is configured to supply the lubricating pressure regulated by the relief valve to the torque converter, the forward / reverse switching device, etc., and this lubricating pressure is used as a source pressure for the control side solenoid valve such as the switching valve. . Then, by outputting an ON signal to the switching solenoid valve under a predetermined condition and operating the control pressure by acting on the switching valve, the sub-pump is driven in single mode without load, and the switching valve is operated by a spring with an OFF signal. , Driven in twin mode with sub-pump load.

[0004]

By the way, in the above-mentioned prior art, the lubricating pressure supplied to the torque converter or the like is used as the source pressure of the solenoid valve for switching the switching valve in the oil pump device. Since it has become
If the pressure changes depending on the usage state of the lubricating pressure on the torque converter side, it directly affects the switching of the switching valve. That is,
In the state where the control pressure of the switching solenoid valve acts on the switching valve to drive in single mode, when the lockup is OFF, the flow rate used by the torque converter increases and the balance with the pump flow rate is lost, and the lubricating pressure decreases Along with this, the control pressure of the switching solenoid valve also drops. Therefore, the switching valve is switched to the sub pump load side by the spring, and the twin mode is set. Then, due to this twin mode, the pump flow rate increases, the lubricating pressure and the control pressure of the switching solenoid valve also increase, the switching valve switches to the sub-pump no-load side, and the single mode is restored again. There is a problem that it is repeated and hunting. Further, in order to avoid such a problem, it is inevitable that the oil pump device is always driven in the twin mode at a low speed when the pump flow rate is small, and an increase in the driving load adversely affects running performance, fuel consumption, and the like. There is.

The present invention has been made in view of this point, and in an oil pressure control system having a variable capacity oil pump device as a hydraulic pressure source, the oil pump is changed in response to changes in the amount of oil used on the torque converter side or the like. The purpose is to reliably prevent hunting for changing the mode of the device.

[0006]

To achieve the above object, according to the present invention, an oil pump device for supplying oil to a continuously variable transmission and various transmission elements has a variable pump capacity oil pump. In a hydraulic control system in which the oil pump is driven in single mode or twin mode depending on the presence or absence of control pressure of the switching solenoid valve, the source pressure circuit of the switching solenoid valve and the release circuit of the lockup clutch are separated. To do.

[0007]

Based on the above structure, the oil pump device of the hydraulic source that supplies the hydraulic control system of the continuously variable transmission and various transmission elements is driven in a single mode or a twin mode, for example, depending on the relationship between the working flow rate and the pump flow rate. The capacity is variable, so that oil is always supplied without excess or deficiency. Since the source pressure circuit of the switching solenoid valve of this oil pump device and the release circuit of the lockup clutch are separated, they do not affect each other, and even if the oil flow rate on the torque converter side changes, the oil There is no hunting for changing the mode of the pump device.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, an outline of the drive system of the continuously variable transmission with lock-up torque converter will be described. Reference numeral 1 is an engine, and a crankshaft 2 of the engine 1 is sequentially transmitted to a torque converter device 3, a forward / reverse switching device 4, a continuously variable transmission 5, and a differential device 6.

The torque converter device 3 includes a crankshaft 2
Through the drive plate 10 to the converter cover 11
And a pump impeller 12a of the torque converter 12. Turbine runner 12b of torque converter 12
Is connected to a turbine shaft 13, and the stator 12c is guided by a one-way clutch 14. The lock-up clutch 15 integrated with the turbine runner 12b is installed in the drive plate 10 so as to be engageable with or disengageable from, and transmits the engine power through either the torque converter 12 or the lock-up clutch 15.

The forward / reverse switching device 4 has a double pinion type planetary gear 16, and the turbine shaft 13 is input to the sun gear 16a and output from the carrier 16b to the primary shaft 20. A forward clutch 17 is provided between the sun gear 16a and the carrier 16b, a reverse brake 18 is provided between the ring gear 16c and the case, and the planetary gear 16 is integrated by the engagement of the forward clutch 17 to integrate the turbine shaft 13 and the primary shaft. Connect directly to 20. Further, the reverse brake 18 is engaged to output reversely rotated power to the primary shaft 20, and the forward clutch 17 and the reverse brake 18 are released to free the planetary gear 16.

The continuously variable transmission 5 is provided with a primary pulley 22 having a variable pulley spacing having a hydraulic cylinder 21 on a primary shaft 20 and a secondary pulley 25 having a hydraulic cylinder 24 similarly on a secondary shaft 23. The drive belt 26 is wound around the belt 22 and the secondary pulley 25. Here, the primary cylinder 21 is set to have a larger pressure receiving area, and the primary pressure changes the ratio of the winding diameter of the drive belt 26 to the primary pulley 22 and the secondary pulley 25 for continuously variable transmission.

The differential device 6 includes a secondary shaft 23, a pair of reduction gears 27, and a pair of reduction gears 27.
The drive gear 29 of the output shaft 28 meshes with the final gear 30. The differential gear 31 of the final gear 30 is connected to the left and right wheels 33 via the axle 32. On the other hand, in order to obtain an oil pressure source for continuously variable transmission control, the oil pump 41 is provided adjacent to the torque converter 12.
The oil pump 41 is connected to the converter cover 11 by the pump drive shaft 35 so as to be constantly driven by the engine power.

Next, the hydraulic control system will be described with reference to FIG. First, the oil passage 51 from the oil pump device 40 that communicates with the oil pan 50 communicates with the secondary pressure control valve 52. The secondary pressure control valve 52 is, for example, a proportional electromagnetic relief valve type, and when the solenoid current Is is input from the control unit 100 to the proportional solenoid 52a, the pump discharge pressure is regulated to generate a predetermined secondary pressure Ps. Is constantly supplied to the secondary cylinder 24 by the oil passage 53, and the pulley pressing force according to the transmission torque or the like is applied. This secondary pressure Ps is applied to the oil passage 55.
Through the primary pressure control valve 56. The primary pressure control valve 56 is, for example, a proportional electromagnetic pressure reducing valve type, and when the solenoid current Ip from the control unit 100 is input to the proportional solenoid 56a, the primary pressure Pp acts on the primary cylinder 21 by the oil passage 57, and the primary pressure Pp is applied. The belt 26 is moved by Pp to control the shift.

Oil pump 41 of oil pump device 40
Is a roller vane type variable capacity type having a plurality of sets of suction and discharge ports, and a main pump 42 having a set of suction ports 42a and a discharge port 42b in the rotation direction of a rotor 41b provided with vanes 41a has the same structure. Suction port 43a and discharge port 43
A sub-pump 43 having b is formed, and both suction ports 42a and 43a communicate with the oil pan 50 through the oil passage 36. The discharge port 42b of the main pump 42 communicates with the secondary pressure control valve 52 via an oil passage 51 to constantly supply oil. The oil passage 37 and the oil passages 36 and 51 of the discharge port 43b of the sub-pump 43 communicate with the switching valve 44.
Is configured to communicate the discharge side oil passage 37 of the sub oil pump 43 with the suction side oil passage 36 or the oil passage 51. The switching valve 44 is provided with a switching solenoid valve 46 that uses the lubricating pressure PL as the original pressure.

The switching solenoid valve 46 is a normally closed three-way valve. The lubricating oil passage 58 communicates with one of the switching valve 44 and the inlet side of the switching solenoid valve 46,
The control pressure oil passage 38 on the outlet side of the switching solenoid valve 46 communicates with the other spring 44b side of the switching valve 44.

On the other hand, in the control unit 100, the pump flow rate and the oil use flow rate are compared and judged, and when the use flow rate is larger, such as during low speed acceleration, the switching solenoid valve 46.
Outputs an ON signal to the spring 44b of the switching valve 44
The control oil pressure Pc ″ is applied to the side to connect the oil passage 37 and the oil passage 51, and the flow rate thereof is added to the secondary pressure control valve 52 to be supplied to enter the twin mode. If there are more, the switching solenoid valve 46
An OFF signal to switch the switching valve 44 to the suction side,
The discharge flow rate of the sub-pump 43 is returned to the suction side for no-load operation, and the single mode is set.

Next, a hydraulic control system such as a torque converter will be described. Here, the oil pressure in the drain side oil passage 58 of the secondary pressure control valve 52 is relatively high, and can be used not only for lubrication but also for a torque converter, an operating pressure for forward / reverse switching, and a control pressure. Therefore, the drain oil is regulated to generate a lubricating pressure, and the lubricating pressure is supplied to each part. Therefore, the oil passage 58 as the first lubricating pressure circuit
Is configured to communicate with the relief valve 59 and regulate a predetermined lubricating pressure PL. The lubricating oil passage 92 branched from the oil passage 58 has a check valve 83 and an orifice 82, and has a belt lubrication nozzle 93 and a secondary cylinder 2.
4 to the balance chamber 24a. An oil passage 94 branched from the oil passage 92 communicates with the lubrication portion of the double pinion type planetary gear 16 of the forward / reverse switching device 4 for lubrication and oil supply. On the other hand, the oil passage 58 and the oil passage 5 of the secondary pressure Ps
1 communicates with the safety lock valve 60.

The safety lock valve 60 includes oil passages 61 and 62.
The manual valve 63 is connected to the forward clutch 17 and the reverse brake 18 via the oil passages 64 and 65. In the safety lock valve 60, the spring and the lubricating pressure PL by the oil passage 66 both act on one side, and the control pressure oil passage 6 of the solenoid valve 67 whose original pressure is the lubricating pressure PL on the other control side.
8 communicate. Normally, the OFF signal from the control unit 100 causes the oil passages 58 and 51 to move to the oil passage 6 as shown in the figure.
1 and 62 communicate with each other. Further, in the case of an abnormality such as a belt slip or mis-shifting of the forward / reverse traveling during traveling, an ON signal is output to the solenoid valve 67 to switch the safety lock valve 60 to the drain side by the control pressure Pc, and the forward / backward switching device. Force 4 into neutral position.

The manual valve 63 switches the oil passage in accordance with each shift operation, and drains both the oil passages 64 and 65 in the parking (P) and neutral (N) ranges, and the oil passage 61 in the D range. The lubricating pressure PL is supplied to the forward clutch 17 in communication with 64. On the other hand, in the R range, a high secondary pressure Ps is supplied to the reverse brake 18 by the communication between the oil passages 62 and 65 to increase the torque capacity, and the reverse gear 18 is engaged with the reaction force of both the input and output torques acting on the ring gear side. It can be fixed.

Oil passage 64 to the forward clutch 17
In the middle of, the accumulator 72 communicates via an oil passage 71 in which the orifice 69 and the check valve 70 are arranged in parallel, and acts as an accumulator so that the forward clutch 17 gradually engages when oil is supplied. Further, the oil passage 65 to the reverse brake 18 is also connected to an accumulator 74 via an oil passage 73 having a similar orifice 69 and check valve 70, and similarly acts as an accumulator.

The oil passage 58 communicates with a lock-up solenoid valve 75 having the lubricating pressure PL as a source pressure, and this control pressure oil passage 76 is provided.
Have a orifice 77 and a check valve 78 that are arranged in parallel, and communicate with the control side of the relief valve 59. The lock-up solenoid valve 75 applies the control pressure Pc ′ to the relief valve 59 by an ON signal when the lock-up is ON, and adjusts the lubricating pressure PL to a low lubricating pressure PL according to the transmission torque. Also lock up O
At the time of FF, the control pressure Pc 'is cut by the OFF signal, and the relief valve 59 adjusts the lubricating pressure PL to a high level according to the transmission torque. In this case, lock-up is ON to OF
When the F mode is switched, the control pressure Pc 'of the relief valve 59 is
Is immediately drained by the check valve 78, and the lubricating pressure PL is rapidly increased in response to an increase in transmission torque. On the other hand, when the lockup mode is switched from OFF to ON, the control pressure Pc ′ is delayed by the orifice 77 and the relief valve 59 is delayed.
During this period, the lubricating pressure PL is kept high to prevent slipping of the belt or the clutch against fluctuations in the transmission torque when the lockup is ON.

Further, in order to prevent hunting of the oil pump device 40 and always secure the oil cooler flow rate, an oil passage 79 having a release pressure valve 80 as a second lubricating pressure circuit communicates with the drain side of the relief valve 59. . The release pressure valve 80 is generated by adjusting the release pressure Pr lower than the above-mentioned lubricating pressure PL, and the drain side oil passage 81 of this release pressure valve 80 directly returns oil to the suction side oil passage 36 of the oil pump device 40. Communicate as you would. The oil passages 58 and 79 for the lubricating pressure PL and the release pressure Pr communicate with the lockup control valve 85, and the lockup control valve 8
5 communicates with the release chamber 15a of the lockup clutch 15 via an oil passage 86, and communicates with the torque converter 12 and the apply chamber 15b of the lockup clutch 15 via an oil passage 87 having a relief valve 88. Further, the two drain side oil passages 89, 91 from the lockup control valve 85
Is connected to the oil cooler 90.

The lockup control valve 85 is a spool 85.
The spring 85b acts on one side of a and the control pressure Pc 'of the oil passage 76 of the lockup solenoid valve 75 acts on the other side. When the lockup is off, the lockup control valve 85 is operated by the spring force, and the oil passage 79
And 86 and 87 and 91 are connected. Lock-up ON
Sometimes, the control pressure Pc 'of the lockup solenoid valve 75
The lock-up control valve 85 is switched by the
And 87 are communicated with each other, the oil passage 86 is drained, and further the oil passages 79 and 89 are communicated with each other.

Next, the operation of this embodiment will be described. First, the converter cover 11 of the torque converter 12 and the drive shaft 35 are driven by the power during engine operation.
The oil pump 41 of the oil pump device 40 is rotationally driven via the. Therefore, the main pump 42 and the sub-pump 43 of the oil pump 41 act as pumps so as to suck in, pressurize and discharge the oil, and the oil discharged from the main pump 42 is always passed through the oil passage 51 and the secondary pressure control valve 52. Is supplied to. Further, the switching valve 44 on the sub-pump operates in a relationship between the lubricating pressure PL, the control pressure Pc ″ equal to the lubricating pressure PL, and the spring force, and switches when the flow rate used is larger, such as during low-speed acceleration. O to solenoid valve 46
N signal is output. Then, the control pressure Pc ″ is generated by the switching solenoid valve 46, the switching valve 44 operates by the spring force as shown in the figure, and the sub-pump 43 is also operated under load to add and supply the flow rate to the secondary pressure control valve 52. In this way, the pump capacity is increased, and when the pump flow rate becomes larger during steady running at high speed, an OFF signal is output to the switching solenoid valve 46, so that the switching valve 4
4 is switched to the suction side by the lubrication pressure PL, whereby the discharge flow rate of the sub-pump 43 returns to the suction side and the pump capacity is reduced by no load operation. Will be supplied.

The oil discharged from the oil pump device 40 is guided to the secondary pressure control valve 52 via the oil passage 51 and is regulated in pressure to generate a predetermined high secondary pressure Ps.
The secondary pressure Ps is always supplied to the secondary cylinder 24, and at the time of starting, the drive belt 26 is moved to the secondary pulley 25 side to be in the low speed stage having the maximum gear ratio. Further, the oil pressure in the drain side oil passage 58 of the secondary pressure control valve 52 is guided to the relief valve 59 to generate a predetermined lubricating pressure PL, and the oil pressure in the drain side oil passage 79 of the relief valve 59 is the release pressure valve 80.
To produce a predetermined release pressure Pr. Lubrication pressure PL
Is a lubrication part such as a belt, and each solenoid valve 46, 67, 7
5 is supplied. The lubrication pressure PL and the secondary pressure Ps are introduced into the manual valve 63 via the safety lock valve 60, and the lubrication pressure PL and the release pressure Pr are introduced into the lockup control valve 85.

Therefore, when shifting to the D range at the time of starting, the lubricating pressure PL of the oil passages 58 and 61 is supplied to the forward clutch 17 via the oil passage 64 while gently controlling the rising of the hydraulic pressure by the accumulator 72 or the like, Therefore, the forward clutch 17 smoothly engages the sun gear 16a and the carrier 16b, and is brought to the forward position. As a result, engine power is transmitted to the torque converter 12 and the turbine shaft 13.
Is input to the primary shaft 20 via the primary pulley 22, the secondary pulley 25, and the belt 26 to output shift power to the secondary shaft 23, which is transmitted to the wheels 33 via the differential device 6 and travels.

At this time, the lockup solenoid valve 75
A lockup OFF signal is input to the lockup control valve 85, so that the release pressure Pr in the oil passage 79 enters the release chamber 15a of the lockup clutch 15 via the oil passage 86 to release the lockup clutch 15. Then
It circulates so as to return to the oil pan 50 via the torque converter 12, the oil passages 87, 91 and the oil cooler 90.
As a result, the torque converter 12 is brought into an operating state and a torque amplification action is performed, and at this time, all the oil from the torque converter 12 flows into the oil cooler 90, and the heat generation in the torque converter 12 is effectively cooled. When the lockup is off, the relief valve 59 adjusts the lubricating pressure PL to a high level to increase the engaging force of the forward clutch 17, and thus the slip is reliably prevented against a large transmission torque during the operation of the converter.

After starting, when the primary pressure Pv is generated by the primary pressure control valve 56 and is supplied to the primary cylinder 21 under each driving and running condition, the belt 26
Shifts toward the primary pulley 22 and undergoes an upshift, and conversely causes a downshift by reducing the primary pressure Pp. Thus, the shift control is performed. Further, in the secondary pressure control valve 52, the secondary pressure Ps is variably controlled by the gear ratio, the engine torque, the torque ratio of the torque converter 12, etc., and always applies the minimum required pulley pressing force according to the transmission torque.

When the torque converter 12 enters the coupling region after the shift is started, an ON signal is input to the lockup solenoid valve 75 to generate a control pressure Pc ', and the lockup control valve 85 is switched. Therefore, this time, the high lubricating pressure PL of the oil passage 58 acts on the apply chamber 15b of the lockup clutch 15 via the torque converter 12, the release chamber 15a is drained, and the lockup clutch 15 is quickly moved by the pressure difference between the two. And it engages firmly. Therefore, in this case, the engine power is the lockup clutch 1.
It will be transmitted efficiently through the 5. At this time, the control pressure Pc 'is supplied to the relief valve 59 after the pressure-holding action by the orifice 77, and the lubricating pressure PL is controlled to decrease according to the transmission torque.

When this lockup is ON, the lubricating pressure PL
Since a large amount of oil is drained to the oil passage 79 of the relief valve 59 by being sealed in the apply chamber 15b, the oil passage 79 communicates with the oil passage 89 by the lockup control valve 85. Therefore, the release pressure Pr of the oil passage 79 flows to the oil cooler 90 as in the case of the lockup OFF, and the oil cooler flow rate is secured. In addition, the release pressure valve 8
The oil drained from 0 is efficiently returned to the oil pump device 40 via the oil passage 81.

On the other hand, when the above lockup is turned off, the lubricating pressure PL by the relief valve 59 of the oil passage 58 is supplied as the original pressure to the switching solenoid valve 46 and the like of the oil pump device 40, whereas the lockup clutch 15 is supplied. The release pressure Pr of the release pressure valve 80 of the drain side oil passage 79 of the relief valve 59 is supplied to the release side and the oil chamber 15a. Therefore, both are separately supplied with different hydraulic pressures and do not influence each other. Therefore, when the lockup is off, even if the oil flow rate on the torque converter side increases under the condition that the oil pump device 40 is in the twin mode with the control pressure Pc ″ by the switching solenoid valve 46, only the release pressure Pr decreases. Then, the original lubricating pressure PL is maintained at a predetermined high hydraulic pressure. Therefore, the control pressure Pc ″ of the switching solenoid valve 46 also becomes high, and the switching valve 44 is maintained in the twin mode switching state. Is
Hunting is prevented.

Although the embodiment of the present invention has been described above, the present invention is not limited to this.

[0033]

As described above, according to the present invention, a continuously variable transmission, a lockup clutch, a torque converter,
In the system in which a variable pump displacement oil pump device is provided in the hydraulic control system that combines the transmission elements of the hydraulic forward / reverse switching device, the source pressure circuit of the switching solenoid valve of the oil pump device and the release of the lockup clutch are released. Since the circuits are configured separately, it is possible to reliably prevent hunting for changing the mode of the oil pump device with respect to changes in the torque converter usage flow rate. Therefore, the oil pump device can be driven in the single mode even at a low speed, and the running performance, fuel consumption, etc. are improved. The drain pressure of the continuously variable transmission hydraulic system is regulated by the relief valve, and the lubricating pressure is used as the source pressure of the switching solenoid valve.The release pressure of the relief valve is regulated by the release pressure valve. Since it is configured to supply to the release side of the clutch, the hydraulic circuit is less wasted and simplified.
Since the oil pressure of the oil cooler is always ensured by using the release pressure by the lockup control valve, the oil cooling efficiency can be kept high.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a hydraulic control device for a continuously variable transmission according to the present invention.

FIG. 2 is a skeleton diagram showing a drive system of a continuously variable transmission.

[Explanation of symbols]

4 Forward / reverse switching device 5 continuously variable transmission 12 Torque converter 15 Lockup clutch 52 Secondary pressure control valve 56 Primary pressure control valve 58 Oil passage (source pressure circuit) 59 relief valve 79 Oil passage (release circuit) 80 Release pressure valve 85 Lock-up control valve 90 oil cooler

Claims (3)

[Claims] 1. An oil pump device for supplying oil to a continuously variable transmission and various transmission elements has an oil pump of variable pump capacity, and this oil pump is of single mode or not depending on the presence or absence of control pressure of a switching solenoid valve. A hydraulic control system for a continuously variable transmission, characterized in that, in a hydraulic control system configured to be driven in a twin mode, a source pressure circuit of a switching solenoid valve and a release circuit of a lockup clutch are configured separately. 2. The source pressure circuit of the switching solenoid valve is a lubricating pressure obtained by adjusting the drain side oil pressure of a continuously variable transmission hydraulic system by a relief valve, and the drain side oil pressure of the relief valve is adjusted by a release pressure valve. 2. The hydraulic control device for a continuously variable transmission according to claim 1, wherein the release pressure is introduced into the oil cooler on the release side of the lockup clutch via the lockup control valve. 3. The lockup control valve introduces the release pressure from the release side of the lockup clutch to the oil cooler via the torque converter and the second drain oil passage when the lockup is off, and the lubricating pressure is supplied when the lockup is on. Is applied to the apply side of the lock-up clutch, and the release pressure is introduced into the oil cooler via the first drain oil passage.
A hydraulic control device for the continuously variable transmission described.