JP3238477B2 - Automatic transmission hydraulic circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for an automatic transmission, and more particularly, to a lock-up clutch for directly connecting an input shaft and an output shaft of a fluid coupling such as a torque converter, and the like. The present invention relates to improvement of a hydraulic circuit having a control function.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic circuit for an automatic transmission of this type, for example, as disclosed in JP-A-1-250667, an engagement-side oil chamber and a release-side oil chamber formed on the left and right sides of a lock-up clutch are disclosed. A lock-up shift valve for selectively supplying oil to the engagement-side oil chamber, and a lock-up shift valve for adjusting oil pressure of the release-side oil chamber in a state where oil is supplied to the engagement-side oil chamber by the lock-up shift valve. And a lock-up control valve for controlling the differential pressure between the hydraulic pressure of the release-side oil chamber and the hydraulic pressure of the release-side oil chamber to control the engagement force of the lock-up clutch, and controlling the operation of the lock-up control valve for controlling the differential pressure. A solenoid valve using a duty control type is known.

[0003]

In the above-described conventional hydraulic circuit, the control of the engagement force of the lock-up clutch is performed by the following method.
For example, it is performed only when the selection lever of the automatic transmission selects the D range, or when the gear is shifted to the fourth forward speed or the third speed in the predetermined range position. On the other hand, the low & reverse brake provided in the speed change mechanism for applying the engine brake is, for example, the second forward movement during the deceleration operation in a state where a range position different from the D range position is selected.
The clutch is engaged in a state where the gear is shifted to the first speed or the first speed, and a dedicated electromagnetic solenoid valve is provided as an electromagnetic solenoid valve for controlling the engagement. When the selection lever is switched from the neutral range to the forward range or the reverse range, the forward clutch or the reverse clutch of the transmission mechanism is engaged. However, a dedicated electromagnetic solenoid valve is also used as an electromagnetic solenoid valve for controlling the engagement. Is provided.

However, in the hydraulic circuit described above, the present inventors have studied the operation timings (including the operation timings) of the various electromagnetic solenoid valves, and found that when the electromagnetic solenoid valves for controlling the engagement force of the lock-up clutch operate. The solenoid valves for controlling the low & reverse brake, the forward clutch or the reverse clutch do not operate. Conversely, when the solenoid valves for controlling the low & reverse brake, etc. operate, the engaging force of the lock-up clutch is controlled. This electromagnetic solenoid valve did not operate, and from this point of view, it was found that the conventional hydraulic circuit was provided with an unnecessarily large number of electromagnetic solenoid valves.

The present invention has been made in view of this point, and an object of the present invention is to provide an electromagnetic solenoid valve for controlling the engagement force of the lock-up clutch, for example , an electromagnetic solenoid valve for controlling the low & reverse brake and the like. An object of the present invention is to reduce the number of electromagnetic solenoid valves to be provided in a hydraulic circuit by being commonly used as a solenoid valve.

At this time, a lock-up clutch and an automatic transmission
A predetermined friction element (for example, low & reverse shake)
When the solenoid valve is shared with the
Simply share a magnetic solenoid valve, and
Lock-up class without any additions or modifications
Tsu engaging force control and control and the Tokoro period of the predetermined friction element Ji
It is configured to ensure good traffic.

[0007]

In order to achieve the above object, a specific solution of the present invention is to provide a lock-up clutch for directly connecting an input shaft and an output shaft of a fluid coupling, A control valve for controlling the engagement force of the up-clutch, and an electromagnetic solenoid valve for controlling the control valve, and a timing different from the control timing of the engagement force of the lock-up clutch based on the operation of the control valve by the electromagnetic solenoid valve and other control valve controlled in, the other
Assuming a hydraulic circuit of an automatic transmission having a predetermined friction element controlled by a control valve , the predetermined friction element is
The lock-up clutch is a lock-up clutch.
At the timing of controlling the fastening force, the hydraulic pressure or oil passage at this point
Formally, the control of the specified friction element by the other control valve is impeded.
Is stopped, and the control valve of the predetermined friction element is controlled by the other control valve.
At the time of imming, the above-mentioned control
Control of lock-up clutch engagement force by valve is blocked
Is when a relationship, controlled by the upper SL solenoid valve the other control valves, the electromagnetic solenoid valve, the
In the oil passages leading to the hydraulic chambers of the control valve and other control valves,
Directly arranged without control valves and other valves other than control valves
And raise the control pressure generated by the solenoid valve.
Control timing of the engagement force of the lock-up clutch;
The control valve is used in both the control timing of the other control valve and the control valve.
In addition, the electromagnetic solenoid valve is made to act on each hydraulic chamber of the other control valve, and the electromagnetic solenoid valve is shared by the control valve and another control valve.

According to a second aspect of the present invention, another control valve of the first aspect of the present invention is specified, and a pressure reducing valve for reducing the engagement pressure supplied to the low & reverse brake is provided. The control pressure generated by the solenoid valve for controlling the control valve is applied.

Further, according to the third aspect of the present invention, another control valve of the first aspect of the present invention is specified to be different from the above, and the selection lever is switched from the neutral range to the forward range or the reverse range. A back pressure control valve of an accumulator disposed in an oil passage for supplying hydraulic pressure to a friction element to be fastened, wherein a control pressure generated by an electromagnetic solenoid valve for control valve control is applied to the back pressure control valve. In addition, in the invention described in claim 4, another function is added to the other control valve of the invention described in claim 1, 2, or 3 to control the control pressure generated by the electromagnetic solenoid valve. Thus, a control oil passage for urging the control valve for controlling the engagement force to the fully engaged position of the lock-up clutch is provided.

[0010]

According to the above-mentioned structure, according to the first aspect of the present invention,
At the time of the lock-up clutch of the fastening force control, control valves that are controlled by an electromagnetic solenoid valve. The other hand, the other control valve
During the control of the predetermined friction element , the other control valve is controlled by an electromagnetic solenoid valve.

At this time, the engagement force control of the lock-up clutch is performed.
When controlling the solenoid valve, other control valves
Operates, but controls the predetermined friction element by the other control valve
In the situation where the oil pressure or oil path formation
Control of a predetermined friction element based on the other control valve
Is not done. On the other hand, a predetermined
When controlling the friction element, the operation of the electromagnetic solenoid valve
The control valve also operates, but lock-up
The control of the latching force depends on the hydraulic pressure or oil path formation at this point.
The lock-up based on the operation of the control valve
No engagement control of the clutch is performed.

In particular, according to the second aspect of the present invention, when controlling the engagement force of the lock-up clutch, the control valve is controlled by the electromagnetic solenoid valve, while the other control valves (low & river) are controlled.
Pressure reducing valve that reduces the engagement pressure supplied to the brake
Even if controlled by an electromagnetic solenoid valve , the low & reverse brake does not supply the fastening pressure to the oil passage to this brake.
It is in a released state because it does not get .

On the other hand, at the time of deceleration operation of the engine, that is, at the time of request for engine braking, the other control valves are controlled by the electromagnetic solenoid valve, and the low & reverse brake is activated.
The engagement operation is performed with the reduced engagement pressure , the reverse driving force is transmitted to the engine, and the control of the engagement force of the lock-up clutch is not required.
The oil pressure control oil passage to the clutch of
Because the converter state of the release state, the control valve the solenoid
Lock-up clutch even if controlled by solenoid valve
Is not performed.

Further, according to the third aspect of the present invention, in a state where the forward range is selected by the selection lever, there is a situation in which the engagement force control of the lock-up clutch is required.
In that situation the control valve is controlled by the solenoid valve
You. At this time , a predetermined friction element (selection lever
Was switched from forward range to forward range or reverse range
Located in the oil supply passage of the fastening pressure to the friction element
Back pressure control valve of the accumulator is the electromagnetic solenoid
The valve operates according to the above-mentioned predetermined friction element.
Indicates that the fastening pressure has already been supplied and
The back pressure control valve regulates the back pressure of the accumulator
This has no effect.

On the other hand, when the selection lever is switched from the neutral range to the forward range or the reverse range, the back pressure control valve of the accumulator is controlled by the electromagnetic solenoid valve, and the engagement pressure to a predetermined friction element gradually increases. to, you entered into the friction element is shock less. At this time, the control of the engagement force of the lock-up clutch is not required.
The lock-up clutch is fastened to this clutch
Fully open converter with closed power control oil passage
Control valve is operated by the solenoid valve
Even if it is controlled, lockup clutch engagement force control is performed
It will not be.

In addition, according to the fourth aspect of the present invention, the control valve for controlling the engagement force of the lock-up clutch can be controlled by another control valve, and the lock-up clutch can be controlled to the fully engaged position. , The lock-up clutch can be quickly controlled to the fully engaged state.

[0017]

As described above, according to the hydraulic circuit of the automatic transmission according to the first, second and third aspects of the present invention, the electromagnetic force of the control valve for controlling the engagement force of the lock-up clutch is obtained. The solenoid valve is commonly used as an electromagnetic solenoid valve for controlling a control valve having another operation timing different from that of another operation timing, so that the required number of electromagnetic solenoid valves can be reduced, and the hydraulic circuit configuration can be simplified and the price can be reduced. Moreover, the electromagnetic
Just by sharing the solenoid valve, the lock-up clutch and
Can be operated as intended with a given friction element
In order to share an electromagnetic solenoid valve, a new switching valve, etc.
Need to be added or to modify existing switching valves, etc.
Light weight, space saving and cost reduction
it can.

[0018] In the invention of claim 4, further to the other control valve, so have a function as a control valve for complete engagement control of the lock-up clutch, unnecessary control valve for the complete engagement Thus, the hydraulic circuit configuration can be further simplified and the price can be further reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an automatic transmission having four forward speeds and one reverse speed. In the figure, reference numeral 1 denotes an engine output shaft, and 2 denotes a torque converter as a fluid coupling including a pump 4, a turbine 5, and a stator 6 connected to a case 3 connected to the engine output shaft 1. The stator 6 is provided so as to be fixed to the case 11 via a one-way clutch 7 for preventing the stator 6 from rotating in the opposite direction to the turbine 5. 10 is the torque converter 2
Is a transmission gear device as a transmission mechanism connected to a converter output shaft 8 connected to the turbine 5 of FIG.

The speed change gear device 10 includes a Ravigneaux type planetary gear mechanism 12 therein.
Small diameter sun gear 13 and large diameter sun gear 14 arranged before and after
A short pinion gear 15 that meshes with the small diameter sun gear 13, a long pinion gear 16 that meshes with the large diameter sun gear 14 and the short pinion gear 15, and a ring gear 18 that meshes with the long pinion gear 16. The small-diameter sun gear 13 includes a forward clutch 20 disposed at the rear thereof, a first one-way clutch 22 connected in series to the clutch 20 to prevent reverse driving of the converter output shaft 8, and a coast clutch connected in parallel to these. It is connected to the output shaft 8 of the torque converter 2 via 21. In addition, large-diameter sun gear 1
Reference numeral 4 is connected to the output shaft 8 of the torque converter 1 via a 2-4 brake 23 disposed diagonally rearward and a reverse clutch 24 disposed behind the 2-4 brake 23. The 2-4 brake 23 includes a brake drum 23a and a brake band 23b applied to the outside of the drum 23a. Further, a low & reverse brake 25 for fixing the long pinion gear 11 via a rear carrier 27 to the long pinion gear 16 and an engine output shaft 2 of the long pinion gear 16 are provided.
Second one-way clutch 26 that allows rotation in the same direction as
Are connected in parallel, and the front carrier 17 is connected to the output shaft 8 of the torque converter 2 via a 3-4 clutch 27. Further, the ring gear 18 is connected to an output gear 19 disposed in front of the ring gear 18.

In addition, reference numeral 30 denotes a lock-up clutch which directly connects the engine output shaft 1 as an input shaft of the torque converter 2 and the converter output shaft 8, and 31 denotes an oil driven by the engine output shaft 1 via the intermediate shaft 9. It is a pump.

Table 1 shows the operating states of the clutches and brakes at the respective speeds in the above configuration.

[0024]

[Table 1]

FIG. 2 shows a specific structure around the lock-up clutch 30 and its fastening force control circuit. In the same figure, an engagement-side oil chamber 30a is formed between the lock-up clutch 30 and the front surface of the torque converter 2 and a release-side oil chamber 30b is formed between the lock-up clutch 30 and the case 3 in front of the lock-up clutch 30. .

The engagement force control circuit has a function of performing the engagement and release operations of the lock-up clutch 30 and the control of the engagement force. In the fastening force control circuit,
40 is a lock-up shift valve, 50 is a lock-up control valve as a control valve for controlling the engagement force of the lock-up clutch 30, and 60 is a low reducing valve as another control valve.

The lock-up shift valve 40 is connected to an engagement pressure oil passage 41 communicating with the engagement oil chamber 30a of the lock-up clutch 30 and a release pressure oil passage 42 communicating with the release oil chamber 30b. In addition, the converter pressure oil passage 43 to which the torque converter pressure acts and the fastening force control oil passage 44 connected to the lock-up control valve 50 are connected to each other.
3 has a function of selectively switching the communication between the engagement pressure oil passage 41 and the release pressure oil passage 42.

That is, the lock-up shift valve 40
Has a spool 40a, a spring 40b contracted to the left of the spool 40a in the drawing, and a hydraulic chamber 40c formed to the right of the spring 40a.
Is connected to an oil passage 45, and a lock-up solenoid valve SOL1 composed of an ON-OFF electromagnetic solenoid valve for opening and closing the oil passage 45 is disposed in the oil passage 45. When the solenoid valve SOL1 is OFF (closed), the spool 40a is positioned at the lower position in the figure by the action of the hydraulic pressure on the hydraulic chamber 40c, and the converter pressure oil passage 43 communicates with the release pressure oil passage 42. At the same time, the engagement pressure oil passage 41 is drained to completely release the lock-up clutch 30. On the other hand, when the solenoid valve SOL1 is ON (opened), the spool 40a is positioned at the upper position in the figure, and the converter pressure oil passage is opened. 43 is communicated with the engagement pressure oil passage 41 and the release pressure oil passage 42 is communicated with the engagement force control oil passage 44.

Further, the lock-up control valve 50 is provided in the engagement side oil chamber of the lock-up clutch 30 at a position where the selection lever of the automatic transmission selects the D (automatic shift from the first speed to the fourth speed) range. It has a function of controlling a differential pressure between the fastening pressure of the release oil chamber 30a and the release pressure of the release-side oil chamber 30b. That is, the lock-up control valve 50
Has a spool 50a, to the right of which is a hydraulic chamber 50b.
However, a control chamber 50c is formed on the left side, and a drain port 50d is formed. Further, the spool 5
0a, the oil pressure of the converter pressure oil passage 43 is
, And the oil pressure of the fastening force control oil passage 44 acts rightward via the oil passage 52. In addition, the above-described fastening force control oil passage 44 is communicatively connected to a substantially central portion of the spool 50a, and is arranged along the oil passage 44.
An oil passage 53 communicating with the converter pressure oil passage 43 is connected in communication. The hydraulic chamber 50b on the right side of the spool 50a
An oil passage 55 is connected to the oil passage 55. A duty solenoid valve SOL2 as a duty control type electromagnetic solenoid valve is directly connected to the oil passage 55 without passing through another switching valve.
It is connected to, and configured to control the hydraulic pressure in the hydraulic chamber 50b of the lockup control valve 50 in accordance with the duty ratio of the duty solenoid valve SOL2.

With the above configuration, the lock-up control valve 50 moves the spool 5 in the D range position.
0a, the hydraulic chamber acting in the left direction in the figure, that is, the hydraulic chamber 5 controlled by the duty solenoid valve SOL2.
0b and the total oil pressure of the converter pressure oil passage 43,
In response to the hydraulic pressure acting on the spool 50a in the right direction, that is, the hydraulic pressure of the engagement force control oil passage 44 (the release pressure of the release-side oil chamber 30b of the lock-up clutch 30), the spool 50a
Reciprocates left and right in the figure and when the total pressure is large, the spool 50a is positioned at the lower position in the figure, and the converter pressure oil passage 43 is communicated with the fastening force control oil passage 44 to be released. When the release pressure of the release-side oil chamber 30b is large while the release pressure of the release-side oil chamber 30b is increased, the spool 50a is positioned at the upper position in the drawing, and the fastening force control oil passage 44 is connected to the drain port 50d. By repeatedly decreasing the release pressure of the communication-side oil chamber 30b, the release pressure of the release-side oil chamber 30b is controlled to a hydraulic pressure value corresponding to the duty ratio of the duty solenoid valve SOL2. The differential pressure between the engagement pressure of the engagement-side oil chamber 30a and the release pressure of the release-side oil chamber 30b is determined by the duty solenoid valve SOL2.
, The engagement force of the lock-up clutch 30 is controlled.

The low reducing valve 60
Means that the selection lever of the automatic transmission is L (forward first speed and second speed
A function as a pressure reducing valve for reducing the engagement pressure supplied to the low & reverse brake 25 in the first speed at the position where the range is selected;
(Automatic transmission from first gear to third gear) Range position and D
A function of controlling the lock-up clutch 30 to a completely engaged state in the range position. The low reducing valve 60 has a spool 60a.
A spring 60b is contracted to the left of Oa, a hydraulic chamber 60c is formed to the right, and a drain port 60d is further formed. An oil passage 65 communicates with the hydraulic chamber 60c, and the duty solenoid valve SOL2 communicates with the oil passage 65.
The duty solenoid valve SOL2 is directly connected to and connected to the lock-up control valve 50 and the low reducing valve 60 without passing through another switching valve.
And is shared by

The low reducing valve 60 has an oil passage 61 to which line pressure is supplied at the L range position.
The oil passages 62 communicating with the engagement oil chambers of the low & reverse brake 25 are connected to each other, and the oil pressure in the oil passages 62 acts on the hydraulic chamber 60b. Further, the low reducing valve 60 has an oil passage 63 (supplied to the 3-4 clutch 27) to which line pressure is supplied at each of the third speed and the fourth speed at the S range position and the D range position. And a control oil passage 64 that communicates with the control chamber 50c of the lock-up control valve 50.

The low reducing valve 6
In the L range position, that is, in the range position different from the D and S range positions, which are the operation timings of the lock-up control valve 50, the spool 60a is controlled by the duty control of the duty solenoid valve SOL2. 62 is alternately communicated with a line pressure oil passage 61 and a drain port 60d to reduce the line pressure of the oil passage 61 to a pressure value corresponding to the duty ratio of the duty solenoid valve SOL2, and conclude the reduced oil pressure. Low & reverse brake via oil passage 62 as pressure
(The low reducing valve 6 as another control valve described above)
(Predetermined friction element controlled by 0) 25. Here, the engagement pressure of the low & reverse brake 25 is desirably set to a higher pressure value as the vehicle speed is higher, as shown in FIG. 3, because the reverse drive torque of the engine is larger at higher vehicle speeds. From this point, based on the engagement pressure-duty ratio characteristic shown in FIG. 4, the duty ratio is set to be lower at higher vehicle speeds.

Further, the low reducing valve 60 is
At the D range position or the S range position where there is a time when the engagement force control of the lock-up clutch 30 is performed, the duty solenoid valve SOL2 is turned on at a duty of 100%.
When controlled to the (fully open) state, the spool 60a
Is positioned at the upper position in the figure, and the line pressure of the oil passage 63 is controlled via the oil passage 64.
Of the spool 50a.
Is positioned at an upper position in the drawing, the engagement force control oil passage 44 communicates with the drain port 50d, and the lock-up clutch 30
The release-side oil chamber 30b is completely released, and the lock-up clutch 30 is completely engaged with the engagement pressure of the engagement-side oil chamber 30a.

Therefore, in the above embodiment, the engagement force control of the lock-up clutch 30 is performed only in the S or D range position of the selection lever of the automatic transmission. That is,
The spool 40 of the lock-up shift valve 40 is controlled by the ON (open) control of the lock-up solenoid valve SOL1.
2 is positioned at the upper position in FIG. 2, and while the engagement pressure is supplied to the engagement-side oil chamber 30 a of the lock-up clutch 30, the release-side oil passage 42 communicating with the release-side oil chamber 30 b is connected to the engagement-force control oil passage 44. In this state, the lock-up control valve 50 alternately communicates the engagement force control oil passage 44 with the converter pressure oil passage 43 and the drain port 50d with the duty ratio of the duty solenoid valve SOL2, thereby establishing the engagement force. The hydraulic pressure (release pressure) of the control oil passage 44 is controlled to a hydraulic pressure corresponding to the duty ratio, whereby the differential pressure between the engagement pressure of the engagement-side oil chamber 30a of the lock-up clutch 30 and the release pressure of the release-side oil chamber 30b is reduced. As a value corresponding to the duty ratio, the engagement force of the lock-up clutch 30 is controlled to a desired value according to the engine operating state.

In this case, the low & reverse brake 25
Is always in the released state as can be seen from Table 1 above. That is, the line pressure is not supplied to the oil passage 61, so that the hydraulic pressure acts on the hydraulic chamber 60c of the low reducing valve 60 with the duty control of the duty solenoid valve SOL2, and the oil passage 61 communicates with the oil passage 62. Even low &
The engagement pressure does not act on the reverse brake 25,
Low & reverse brake 2 by using the flushing valve 60
The control for reducing the engagement pressure of No. 5 is prohibited.

Further, at the time of controlling the engagement force of the lock-up clutch 30, when it is required to completely engage the lock-up clutch 30, the duty solenoid valve S
OL2 is ON (fully opened) at a duty ratio of 100%. This allows the low reducing valve 6
The hydraulic pressure in the hydraulic chamber 60c of 0 is discharged, the spool 60a is switched to the upper position in FIG. 2, and the line pressure of the oil passage 63 is introduced into the control chamber 50c of the lock-up control valve 50 via the oil passage 64, The spool 50a is forcibly switched to the upper position in FIG.
4 always communicates with the drain port 50d of the lock-up control valve 50, the oil in the release-side oil chamber 30b is quickly discharged, and the lock-up clutch 30
The complete fastening operation immediately follows the hydraulic pressure of 0a.

On the other hand, when the selection lever of the automatic transmission is at the L range position, the line pressure is supplied to the oil passage 61,
In this state, when the duty solenoid valve SOL2 controls the oil pressure of the oil passage 65 at a duty ratio corresponding to the vehicle speed,
The oil pressure in the oil passage 62 is controlled by the low reducing valve 60 to an oil pressure corresponding to the duty ratio, and this oil pressure is supplied to the low & reverse brake 25 as an engagement pressure.
As a result, the low & reverse brake 25 operates with a stronger engaging force as the vehicle speed increases, and the reverse driving torque of the engine is transmitted to the engine through the low & reverse brake 25 satisfactorily, and the engine brake operates properly. I do.

In that case, the duty solenoid valve S
The hydraulic pressure generated in the oil passage 55 by the duty ratio control of the OL 2 is applied to the hydraulic chamber 50 of the lock-up control valve 50.
b, the spool 50a of the lock-up control valve 50 operates, but the lock-up shift valve 40 turns off the lock-up solenoid valve SOL1.
2, the fastening force control oil passage 44 is shut off, the converter pressure oil passage 43 communicates with the release oil passage 42, and a release pressure acts on the release oil chamber 30b. At the same time, the engagement side oil passage 41 is drained and the hydraulic pressure of the engagement side oil chamber is discharged, so that the lockup clutch 30 is controlled to the converter state, and the lockup control is performed.
Of the lock-up clutch 30 by the valve 50
The control is interrupted, and there is no problem in controlling the lock-up clutch 30.

Here, the duty solenoid valve SOL2 for controlling the engagement force of the lock-up clutch 30 is commonly used as the solenoid valve of the low reduction sine valve 60. Simple and inexpensive. Change
When the duty solenoid valve SOL2 is shared
New switching valves, etc., or existing switching valves
Lightweight, space saving and low cost because no modification is required
Is possible.

In addition, since the valve for controlling the lock-up clutch 30 to be in the fully engaged state when controlling the engagement force of the lock-up clutch 30 is also used by the low-reducing valve 60, the valve for controlling the lock-up clutch 30 to be in the fully engaged state is required. This can be eliminated, and the hydraulic circuit configuration can be made simpler and less expensive.

FIG. 5 shows an embodiment of the third aspect of the present invention. In the figure, 40 is a lock-up shift valve,
SOL1 lockup solenoid valve for controlling the lock-up shift valve 40, the lock-up control valve 50, SOL2 is I duty solenoid valve der as an electromagnetic solenoid valve that controls the lock-up control valve 50, other switching Valves etc.
Lock-up controller directly via oil passage 55
Ru is communicated with the hydraulic chamber 50b of the trawl valve 50.

K2 is the forward clutch or reverse clutch (predetermined friction element) shown in FIG. 1, and as can be seen from Table 1, the selection lever is set to N (neutral).
The clutch K2 is a friction element that is engaged when switched from the range to the forward range of D, S or L or the reverse range of R, and thereafter maintains the engaged state.
1, the line pressure is supplied as the fastening pressure, and the fastening operation is performed. Further, an accumulator 72 is disposed in the oil passage 71 for supplying the line pressure. The accumulator 7
Reference numeral 2 denotes a back pressure control valve for adjusting the oil pressure of the back pressure chamber 72b by adjusting the oil pressure of the oil passage 73 so that the oil passage 73 is connected to the back pressure chamber 72b of the piston 72a. The modulator valve 75 is interposed. The modulator valve 75 has a spool 75a, a hydraulic chamber 75b formed on the right side of the spool 75a in the drawing, and a drain port 75c, and a back of the accumulator 72 on the left side of the spool 75a in the drawing. The pressure in the oil passage 73 communicating with the pressure chamber 75b acts via the oil passage 76. The hydraulic chamber 75b of the modulator valve 75 includes:
The duty solenoid valve SOL2 of the lock-up control valve 50 is switched to another mode via the oil passage 77.
They are connected directly without a valve .

With the above configuration, the modulator valve 7
5, when the duty solenoid valve SOL2 generates a control pressure according to the duty ratio, the control pressure acts on the hydraulic chamber 75b, and the accumulator 7 according to the hydraulic pressure.
An oil passage 73 communicating with the second back pressure chamber 72b is communicated with the communication and drain port 75c to adjust the hydraulic pressure acting on the back pressure chamber 72b of the accumulator 72.

In FIG. 5, reference numeral 80 denotes a second lock-up shift valve which controls the lock-up shift valve 40 to control the lock-up clutch 30 to a completely engaged state. 81 is a reducing valve,
The line pressure is reduced, and the reduced line pressure is supplied to the oil passage 71 and the like.

Therefore, in this embodiment, when the selector lever is switched from the N range position to the D, S or L range position, as shown in Table 1, the forward or reverse clutch K2 must be engaged. Therefore, the line pressure is supplied to the forward or reverse clutch K2 via the oil passage 71, and the clutch K2 is engaged.

At this time, the increase in the fastening pressure supplied through the oil passage 71 is adjusted by the back pressure of the back pressure chamber 72b of the accumulator 72. That is, the duty solenoid valve SO
A hydraulic pressure is generated by the duty control of L2, and this hydraulic pressure acts on a hydraulic pressure chamber 75b of the modulator valve 75, whereby the hydraulic pressure of the oil passage 73 communicating with the back pressure chamber 72b of the accumulator 72 is adjusted. The increase in the engagement pressure to the reverse clutch K2 can be appropriately adjusted by the duty ratio of the duty solenoid valve SOL2, and the engagement operation of the forward or reverse clutch K2 can be performed with less shock.

In particular, when the engine is cold, the viscosity of the oil is low, and the responsiveness of the supply of the engagement pressure to the clutch K2 is apt to decrease. Therefore, when the line pressure is controlled to be high, the back pressure chamber of the accumulator 72 is controlled. In the normal structure for supplying the line pressure to the back pressure chamber 72b, the back pressure in the back pressure chamber 72b also increases, and the clutch K2
A large shock is likely to occur in the fastening of. However, in this embodiment, even when the line pressure rise is corrected at a low oil temperature, the back pressure of the back pressure chamber 72b is appropriately adjusted by the duty control of the duty solenoid valve SOL2 separately from the line pressure correction. Therefore, regardless of the level of the oil temperature, the engagement of the forward or reverse clutch K2 can always be performed quickly and with less shock.

At this time, the lock-up control valve 50 operates by the duty control of the duty solenoid valve SOL2.
Operated by the FF (closed) operation, the converter pressure oil passage 43
Hydraulic pressure is applied to the release-side oil chamber 30b via the release-side oil passage 42, the lock-up clutch 30 is fully disengaged, and has a converter state and the lock-up clutch 3
The way the engagement force control oil passage 44 to 0 in the lockup Pushifuto
Locked up by the valve 40
Fastening pressure of fastening force control oil passage 44 by troll valve 50
Control is blocked.

On the other hand, when the engagement force control of the lock-up clutch 30 is performed in the D or S range position, the duty solenoid valve SO
The lock-up clutch 30 is controlled by the duty control of L2.
The differential pressure of the hydraulic pressure between the engagement side oil chamber 30a and the release side oil chamber 30b is adjusted. In this case, the forward or reverse clutch K2 is always engaged by the supply of the engagement pressure from the oil passage 71. since, according to the motor even du regulator valve 75 is pressurized back pressure in the back pressure chamber 72b is adjusted for operation and the accumulator 72, Mo du regulator valve 75 by duty control of the duty solenoid valve SOL2 follower
The control of the engaging force of the ward or reverse clutch K2 is blocked.
It has been, no effect.

Therefore, also in the present embodiment, the duty solenoid valve SOL2 for controlling the engagement force of the lock-up clutch 30 is commonly used as the solenoid valve of the modulator valve 75, so that the hydraulic circuit configuration can be made simple and inexpensive. In addition, new or existing switching valves such as switching valves
Lightweight and space-saving can be achieved without the need for modifications such as
It has a certain effect.

In the present embodiment, the second lock-up shift valve 80 is provided so that the lock-up clutch 30 is completely engaged. However, this function can be added to the modulator valve 75. Of course.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of an automatic transmission with four forward speeds.

FIG. 2 is a diagram showing a hydraulic circuit for complete engagement, release, and engagement force control of a lock-up clutch.

FIG. 3 is a diagram showing the engagement pressure characteristics of a low & reverse brake with respect to the vehicle speed.

FIG. 4 is a graph showing the engagement pressure characteristics of a low & reverse brake with respect to the duty ratio of a duty solenoid valve.

FIG. 5 is a diagram corresponding to FIG. 2, showing another embodiment.

[Explanation of symbols]

1 Engine output shaft (input shaft to torque converter) 2 Torque converter (fluid coupling) 8 Converter output shaft (output shaft) 25 Low & reverse brake (predetermined friction
Friction element) 30 lock-up clutch 30a engagement-side oil chamber 30b release-side oil chamber 40 lock-up shift valve 50 lock-up control valve (control valve, pressure reducing valve) 55, 65 oil path 60 low reducing valve (other control valve) 64 Control oil passage SOL2 Duty solenoid valve (Electromagnetic solenoid valve) 72 Accumulator 75 Modulator valve (Back pressure control valve) K2 forward clutch or reverse valve
Latch (predetermined friction element)

Continued on the front page (72) Inventor Junichi Doi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Hidetoshi Kambara 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (56) References JP-A-4-145262 (JP, A) JP-A-62-41466 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61 / 24 F16H 63/40-63/48

Claims (4)

(57) [Claims] A lock-up clutch that directly connects an input shaft and an output shaft of a fluid coupling; a control valve that controls an engagement force of the lock-up clutch; and an electromagnetic solenoid valve that controls the control valve. with the other control valve which is controlled at a timing different from that of the control timing of the engagement force of the lock-up clutch based on the operation of the control valve by the electromagnetic solenoid valve, and a predetermined frictional element is controlled by the other control valve The predetermined friction element and the lock-up clutch are
In the timing of controlling the engagement force of the
Predetermined by the other control valves above at the time of hydraulic or oil path formation
The control of the friction element of the
At the constant friction element control timing, the hydraulic pressure or
Is the lock-up clutch by the above control valve
In a relationship in which the control of the fastening force is blocked, the other control valve is controlled by the electromagnetic solenoid valve, and the electromagnetic solenoid valve is connected to the control valve and the other control valve.
In the oil passage leading to each hydraulic chamber,
The control pressure generated by the solenoid valve is disposed directly without any other outside valve, and the control pressure generated by the solenoid valve is controlled by the solenoid valve.
Control timing of the engagement force of the
The above control valve and the control timing of other control valves
A hydraulic circuit for an automatic transmission , wherein the electromagnetic solenoid valve is shared by the control valve and another control valve by acting on each hydraulic chamber of another control valve. 2. The control valve according to claim 1, wherein the control valve is a pressure reducing valve for reducing a fastening pressure supplied to a low and reverse brake, and a control pressure generated by an electromagnetic solenoid valve for controlling the control valve acts on the pressure reducing valve. The hydraulic circuit for an automatic transmission according to claim 1, wherein: 3. A back pressure control valve of an accumulator disposed in an oil passage for supplying oil pressure to a friction element to be engaged when a selection lever is switched from a neutral range to a forward range or a reverse range. The hydraulic circuit for an automatic transmission according to claim 1, wherein a control pressure generated by an electromagnetic solenoid valve for controlling the control valve acts on the back pressure control valve. 4. The control valve according to claim 1, further comprising a control oil passage for urging the control valve for controlling the engagement force to a fully engaged position of the lock-up clutch by a control pressure generated by the electromagnetic solenoid valve. The hydraulic circuit for an automatic transmission according to any one of claims 1, 2 and 3.