JP2000035113A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for automatic transmission, which simplifies the structure of a fail-safe valve for preventing a double engagement. SOLUTION: OD/C2, 2-5/B3, and UD/C4 are friction elements which cause a double engagement when they are engaged with each other simultaneously. Control valves 10, 16, 20 comprise control means for controlling the pressures applied to OD/C2, 2-5/B3, and UD/C4 by indicator pressures of a duty electromagnetic valve (not shown). When the pressure applied to OD/C2 and UD/C4 are both line pressures, a fail-safe valve 14 is moved to the left regardless of the pressure applied to 2-5/B3. At that time, a connecting path 174 is connected to a drain passage 190 to release 2-5/B3. Since only by the pressures applied to UD/C4 and OD/C2 out of OD/C2, 2-5/B3, and UD/C4 which cause the double engagement when they are engaged with each other simultaneously, the fail-safe valve 14 is switched to prevent the double engagement, the configuration of the fail-safe valve 14 becomes simple.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission control device for hydraulically controlling a transmission mechanism of an automatic transmission.

[0002]

2. Description of the Related Art Conventionally, an automatic transmission often used for vehicles and the like has a plurality of friction elements for switching gears by being engaged or disengaged. Shift control is performed by controlling the pressure applied to the elements. The combination of the friction elements to be engaged is determined according to each shift speed, and interlocking (double engagement) of the gear train may occur when the friction elements other than the combination are engaged. For example, C for 4th forward speed
In the case of an R-CR type automatic transmission, an underdrive clutch (UD / C), which is a friction element, and a 2-4 brake (2-
4 / B) and the overdrive clutch (OD / C) are engaged at the same time, a double engagement occurs.

In the hydraulic control apparatus for an automatic transmission disclosed in Japanese Patent Application Laid-Open No. Sho 63-210443, UD / C, 2-4 / B and OD / The pressure applied to C is introduced into a fail-safe valve constituted by a spool valve, and is used as a pressure for switching the fail-safe valve. Further, a specified pressure for pressing the fail-safe valve in a direction opposite to the pressure applied to the three friction elements introduced to the fail-safe valve is introduced to the fail-safe valve.

[0004] UD /
When all the pressures applied to C, 2-4 / B and OD / C become the engagement hydraulic pressure, the fail-safe valve is switched against the specified pressure. The UD /
C, controlling the pressure applied to 2-4 / B and OD / C,
UD / C, 2-4 / B and OD / C are prevented from simultaneously engaging. The total force received by the failsafe valve from the pressure applied to UD / C, 2-4 / B and OD / C is the sum of the product of each pressure and its pressure receiving area. And
The total value of the forces received by the fail-safe valve from the three friction elements when the fail-safe valve is switched to prevent double engagement is the force at which the prescribed pressure presses the fail-safe valve, that is, the prescribed pressure and the prescribed pressure. It is specified by the product of the pressure receiving area. Since the magnitude of the pressure applied to the friction element determines the torque transmitted by the friction element, the specified pressure is determined by UD / C, 2-4 / B and OD /
C defines the total torque. In the fail-safe valve, the pressure receiving surfaces of these four pressures are formed to have different diameters.

UD / C, 2-4 / B and OD / C are 2
When the gear is switched from third gear to third gear and third gear to fourth gear,
The transmission is shifted by adjusting the increase and decrease of the pressure applied to each friction element and transferring torque between the friction elements. If the torque of the entire friction element becomes smaller than a predetermined range during the speed change process, engine idling occurs,
If it exceeds the predetermined range, double engagement occurs. Blowing or double engagement of the engine can cause discomfort and shock to the occupant. If the pressure applied to each friction element is not properly controlled even after the shift is completed, the engine will blow or double engagement will occur. The above-described fail-safe valve is adapted to respond to the three types of pressures introduced into the fail-safe valve in order to accurately grasp fluctuations in the pressure applied to the friction elements during and after shifting and prevent double engagement. Three types of pressure receiving surfaces having different pressure receiving areas are provided.

[0006]

Here, the engagement torque of the entire friction element should be originally defined according to the value of the turbine torque input to the automatic transmission. Since the turbine torque fluctuates according to the engine operation state such as the throttle opening, the smaller the turbine torque, the smaller the torque transmitted by the automatic transmission and the smaller the pressure applied to the engaging friction element. Therefore, it is desirable to adjust the line pressure according to the turbine torque and accurately set the specified pressure. However, accurate measurement and estimation of turbine torque is difficult.

[0007] Some conventional hydraulic control devices for automatic transmissions use a line pressure as a source pressure of the hydraulic control device as a specified pressure for specifying a torque at the time of switching a fail-safe valve. For example, it is conceivable to change the value of the line pressure in accordance with the low gear (first and second gears), the high gear (third and fourth gears), and the reverse. Does not switch. That is, regardless of the magnitude of the turbine torque, the specified pressure with an added margin is set at each shift speed. Since a large specified pressure is set even when the turbine torque is small, that is, when the throttle opening is small,
If the plurality of frictional elements that cause double engagement are engaged with hydraulic pressure that does not damage the gear train, the fail-safe valve does not switch.

[0008] Consider a case where a margin is hardly added to the specified pressure. In a hydraulic control device that directly controls the pressure applied to a friction element by a duty solenoid valve, when performing so-called quick filling control in which the engagement speed of the friction element is improved by shortening the time for the clutch piston to move a waste stroke, If a margin is not added to the pressure, the fail-safe valve is switched and the friction element to be released is released before the engagement torque is generated in the friction element to be engaged due to the pressure increase during the rapid filling control. As a result, the torque of the entire friction element is reduced, and engine idling occurs. Further, the engine may be easily blown off even during steady running due to a slight decrease in line pressure or an impact from a road surface.

It is more desirable for the engine to be engaged with a plurality of friction elements that cause double engagement with a hydraulic pressure that does not cause damage to the gear train than to cause the engine to idle, so that a certain margin is added to the specified pressure. I have no choice. As described above, a complicated fail-safe valve having a structure having a different pressure receiving area for each pressure introduced into the fail-safe valve is used to prevent double engagement with high precision corresponding to the pressure applied to each friction element. However, double engagement cannot be prevented with high precision because the specified pressure includes a margin.

An object of the present invention is to provide an automatic transmission control device in which the structure of a fail-safe valve for preventing double engagement is simplified.

[0011]

According to the automatic transmission control apparatus of the present invention, the first friction element and the second friction element which cause double engagement when engaged simultaneously. The switching means is switched by the hydraulic pressure applied to the second friction element among the elements. If the hydraulic pressure applied to the second frictional element is the engagement pressure, the switching means is switched only by the hydraulic pressure applied to the second frictional element, whereby the hydraulic pressure applied to the first frictional element can be reduced to prevent double engagement. . Since the switching means is switched only by the hydraulic pressure applied to the second friction element among the first friction element and the second friction element which are double-engaged, the configuration of the switching means is simplified.

According to the control device for an automatic transmission according to the second aspect of the present invention, the original pressure can be introduced to the switching means so as to press the switching means in a direction opposite to the hydraulic pressure applied to the second friction element. Accordingly, there is no need to generate a new hydraulic pressure as the specified pressure that defines the hydraulic pressure applied to the second friction element when the switching means is switched, so that the configuration of the hydraulic circuit is simplified.

According to a fifth aspect of the present invention, there is provided a control device for an automatic transmission, comprising a biasing means for biasing the switching means in the same direction as the direction in which the hydraulic pressure applied to the second friction element presses the switching means. ing. The biasing force of the biasing means acts in a direction to prevent double engagement. For example, when the hydraulic pressure applied to the switching means is unstable when the engine is started, the urging force of the urging means acts in the direction to prevent double engagement, so that even when the hydraulic pressure is unstable, double engagement is prevented. it can.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. 1 and 2 show an embodiment in which the automatic transmission control device of the present invention is applied to a hydraulic control device for an automatic transmission of five forward speeds. Reverse clutch (R / C) 1, Overdrive clutch (OD / C)
2, 2-5 brake (2-5 / B) 3, underdrive clutch (UD / C) 4, low reverse brake (L
R / B) 5, reduction brake (Red / B) 6,
The direct clutch (D / C) 7 is a friction element that is engaged or released by hydraulic pressure. 2-5 / B3 is a first friction element, and OD / C2 and UD / C4 are second friction elements.

Control valve 10 and duty solenoid valve 12, control valve 16 and duty solenoid valve 18, control valve 20 and duty solenoid valve 22, control valve 26 and duty solenoid valve 28, control valve 32 and duty solenoid valve 34 The control means controls the pressure applied to each friction element other than / C1. Only when the driver selects R of the shift lever, the line pressure as a source pressure for hydraulically controlling each friction element is directly applied to the R / C1 via the manual valve 38.

The control valve 16 and the duty solenoid valve 18 constitute a first control means, and the control valve 10 and the duty solenoid valve 12, and the control valve 20 and the duty solenoid valve 22 constitute a second control means. The output pressure of each control valve is controlled by applying the command pressure, which is the output pressure of the duty solenoid valves 12, 18, 22, 28, 34, to the right ends of the control valves 10, 16, 20, 26, 32 in FIG. You.

The fail-safe valves 14, 24, 30 are valves that prevent double engagement of the friction elements. The fail-safe valve 14 constitutes switching means, and includes OD / C2 and UD / C2.
When both pressures applied to / C4 are line pressures,
Fail-safe valve 14 regardless of pressure applied to 5 / B3
Moves to the left side of FIG. The fail-safe valve 14 is constituted by a spool valve, and the communication passages 170, 171, 17
The pressure receiving surfaces receiving the pressures of 2 have different diameters, and one end receiving the pressure of the communication passages 171 and 172 has two stages.

The fail-safe valve 24 includes a communication passage 183,
2 moves to the right side in FIG. 2 only when the drain pressure is 185 and the communication path 187 is the line pressure. The fail-safe valve 30 moves to the left in FIG. 2 only when the communication path 127 is at the line pressure and the communication path 161 is at the drain pressure, and connects the communication path 130 and the communication path 191. It communicates with the drain passage 131.

The high pressure selection valve 29 selects the pressure on the high pressure side and applies it to the LR / B5. The first speed determination valve 36 is a valve for determining whether or not the shift speed is the first speed.
Is moved to the right in FIG. 2 by the urging force of the spring 37 only when both are at the drain pressure. The manual valve 38 is connected to the shift lever via a link, and the range of the shift lever P (parking), R (reverse), N (neutral), D, 1, 2, 3, 4 ( The manual valve 38 is switched in response to the forward movement.

The hydraulic pump 40 has a suction port 41 of an oil pan.
And supplies the hydraulic oil to each friction element and the lock-up clutch 51. The line pressure control valve 42 controls the secondary valve 4 based on the pressure indicated by the duty solenoid valve 44.
3 together with each friction element and lock-up clutch 51
Of working pressure. The pressure reduction control valve 45 is a valve that reduces the line pressure generated by the line pressure control valve 42. The hydraulic pump 40, the line pressure control valve 42, and the duty solenoid valve 44 constitute a source pressure generating means, and generate a line which is a source pressure of the pressure applied to each friction element. The oil cooler 46 is provided for cooling the working oil and exchanging heat.

The lock-up clutch 51 connects or disconnects the output shaft on the engine side and the input shaft on the automatic transmission side, and transmits the power from the engine to the automatic transmission by bypassing the torque converter 50 at the time of connection. . The lock-up on / off solenoid valve 53 is a lock-up relay.
An instruction pressure for switching the valve 52 is controlled. The lockup control valve 54 controls the pressure applied to the lockup clutch 51 based on the command pressure of the duty solenoid valve 55.

The position of the manual valve 38 changes according to the driver's operation of the shift lever, and the position switches between the line pressure communication passage 120 branched from the communication passage 100 and the drain pressure drain passage 121 depending on the position. It controls whether the pressure in the communication passage 122 and the communication passage 123 becomes a line pressure or a drain pressure. The switching position of the manual valve 38 corresponds to “P, R,
N, D, 4, 3, 2, 1 ".
“P, N” and “D, 4, 3, 2, 1” are the same communication patterns. As shown in FIG. 3, a combination of engagement or disengagement of each friction element is determined in advance according to each shift speed, and the ECU (El
The gearshift command is output from the ectric control unit). In FIG. 3, the speed indicated by R corresponds to the R range, and the speed indicated by N corresponds to the P range and the N range. 1s
The gears indicated by t, 2nd, 3rd, 4th, 5th are D, 4,
The range specified by each of the ranges 3, 2, and 1 is different.
In first gear, LR / B5 is engaged or released according to the range selected by the shift lever. For example, the clutch is engaged at the first speed in one range, and is released at the first speed in the D range.

Next, generation of hydraulic pressure for controlling the hydraulic circuit according to the present embodiment will be described. Hydraulic pump 40 sucks hydraulic oil from the suction port 41 of the oil pan, and
High pressure is discharged to 0, 101, and 102. The line pressure control valve 42 controls the line pressure by discharging a part of the hydraulic oil sent from the communication passage 101 to the communication passages 103 and 104.

A pressure-reducing control valve 45 is provided on a path branched from the communication path 100 to the communication path 110. The output pressure of the pressure reduction control valve 45 is introduced from the communication path 111 to the right side of the pressure reduction control valve 45 in FIG. Due to the balance between the force received by the pressure reducing control valve 45 from the output pressure and the urging force of the spring 45a, the communication path 11
If the pressure of 1 does not exceed the line pressure, for example, if the line pressure is 1.6 MPa at the maximum, the pressure is controlled to about 0.4 MPa. This pressure is called the modulation pressure. Pressure reducing control valve 45
Is guided to the duty solenoid valve 44 through the throttle 114. The duty solenoid valve 44 is generally duty-controlled by an output signal from an ECU (not shown) so as to set an appropriate line pressure in accordance with a vehicle operating state such as a throttle opening, an engine torque and a turbine torque. Instructed pressure 115
Is output to The communication passage 115 is connected to the left end of the line pressure control valve 42 in FIG. In FIG. 2, the line pressure is introduced into the different-diameter portion on the right side of the line pressure control valve 42 through a communication passage 105 branched from the communication passage 102, which is a line pressure passage. Feedback controlled.

The communication path 142 is a communication path 1 having a modulated pressure.
It branches from 11 and is connected to the duty solenoid valve 34. The communication paths 150, 151, 152, and 153 are branched from the communication path 142, and the modulated pressure is introduced into the duty solenoid valves 12, 18, 22, and 28. The command pressures of the duty solenoid valves 12, 18, 22, and 28 pass through respective communication passages, and the control valves 10, 16, 20, 2, and 2 in FIG.
6 to the right.

The operating principle of the hydraulic circuit of each friction element except for R / C1 is basically the same except for the presence or absence of a fail-safe valve, so the hydraulic circuit for 2-5 / B3 is taken as an example and its operation will be described. Next, a description will be given.

The modulation pressure in the communication passage 142 is
An instruction pressure which is introduced from 51 into the duty solenoid valve 18 and whose duty ratio is controlled in accordance with an instruction from the ECU is introduced from the duty solenoid valve 18 to the right end of the control valve 16 in FIG. The two lands of the control valve 16 have different diameters,
In FIG. 2, the land diameter on the right side is larger than that on the left side.
Therefore, a rightward pressing force is generated in the control valve 16 by the pressure of the communication passage 173. When the pressing force, the force received by the control valve 16 from the instruction pressure of the duty solenoid valve 18 and the urging force of the spring 17 are balanced, the communication path 125
Is the line pressure, the pressure in the communication passage 173 is controlled to an intermediate pressure between the communication passage 125 and the drain passage 154 according to the instruction pressure of the duty solenoid valve 18.

The communication passage 173 or the drain passages 190 and 2
Communication with the communication path 174 connected to −5 / B3 is performed by switching the fail-safe valve 14. Communication paths 171 and 172 connected to OD / C2 and UD / C4, respectively.
Are connected to the fail-safe valve 14, and the communication passage 170 is connected to the fail-safe valve 14 so as to press the fail-safe valve 14 in a direction opposite to the pressure of these communication passages. In the forward range D, 4, 3, 2, 1, the communication path 1
The pressure at 70 is the line pressure. A spring 15 as a biasing means is disposed at one end of the fail-safe valve 14 to which the communication paths 171 and 172 are connected.
The fail-safe valve 14 is urged in the same direction as the pressures of 1,172. The pressure receiving area of the fail-safe valve 14 and the urging force of the spring 15 are set such that the fail-safe valve 14 moves to the left from the position shown in FIG. 2 when both the OD / C2 and the UD / C4 have a line pressure. Have been. When the fail-safe valve 14 moves to the left in FIG. 2, the communication passage 174 and the drain passage 190 communicate with each other, so that the output pressure of the control valve 16, that is, the pressure of the communication passage 173 is 2-5 / B3 regardless of the level of the pressure. The applied pressure becomes the drain pressure. Therefore, OD / C2, 2-5 / B3 and U
D / C4 can be prevented from engaging at the same time. Also,
Since the spring 15 urges the fail-safe valve 14 in the same direction as the pressure in the communication passages 171 and 172, even if the pressure in the communication passages 170, 171 and 172 at the time of starting the engine is unstable, the OD / C2 And 2-5 / B3 and UD / C4 can be prevented from being double-engaged.

When the fail-safe valve 14 is at the position shown in FIG. 2, the communication passage 174 and the communication passage 173 communicate with each other.
, Ie, the pressure in the communication passage 173, is applied to 2-5 / B3.

Next, the operation of the hydraulic control device in each range selected by the shift lever will be described. (1) In the P and N ranges, the communication passages 122 and 123 communicate with the drain passage 121, and the communication passages 124, 125 and 126 branched from the communication passage 123 also have a drain pressure. Therefore, the R / C1, OD / C2, and R / C1, which are directly or indirectly connected to the communication paths 122, 124, 125, and 126, respectively.
-5 / B3 and UD / C4 are released and are not engaged by any control command from the ECU.

Since the communication paths 180 and 181 are both drain pressures, the communication path 183 which is the output pressure of the first speed determination valve 36
Is the drain pressure. Further, since both of the communication paths 185 and 187 have a drain pressure, the fail-safe valve 24 moves to the left in FIG. 2 by the urging force of the spring 25, and the communication path 189 and the drain path 192 communicate with each other. Therefore,
LR / B5 is released.

Since the communication passage 140 branched from the communication passage 100 does not pass through the manual valve 38 and is connected to the control valve 32 which is a control means of Red / B6, the communication passage 140 is connected to the control valve 32 regardless of the selected range. Pressure has been introduced. Therefore, the communication passage 161 is set to the line pressure by the duty solenoid valve 34 whose duty ratio is controlled based on a command from the ECU, and Red / B6 is engaged.

The communication passage 127 is branched from the communication passage 140, and the pressure is always the line pressure regardless of the position of the manual valve 38. Further, since the pressure of the communication path 161 is set to the line pressure due to the engagement of the Red / B6, the fail-safe valve 30 moves to the right in FIG. 131
Communicates with Thus, the pressure applied to the D / C 7 becomes the drain pressure, and the D / C 7 is released.

Since the line pressure is introduced to the corresponding control valve, and only the friction element selected by each fail-safe valve can be engaged, the combination of FIG. Engage.

(2) Next, the forward range "D, 4, 3, 2,
"1" will be described using the D range as an example. 4, 3,
The operation of each shift speed in the 2nd and 1st ranges is the same as the corresponding shift speed in the D range, and thus the description is omitted.

In the D range, the communication passage 122 has a drain pressure, and the communication passage 123 has a line pressure. Since R / C1 is connected to communication path 122, R / C1
/ C1 is released. The communication paths 124, 125, 126 branched from the communication path 123 are connected to the control valves 10, 16, 20. Further, as described above, since the communication path 140 connected to the control valve 32 has a line pressure, OD / C2,
2-5 / B3, UD / C4 and Red / B6 are engageable. Further, the communication path 189 and the communication path 188 can communicate with each other by switching the fail-safe valve 24. Further, since the failsafe valve 30 is switched according to the level of the pressure applied to the Red / B6, the communication paths 130 and 19
1, and the communication path 191 and the communication path 188 can communicate with each other. Therefore, LR / B5 and D / C7 can be engaged.

Next, the operation of each shift speed in the D range will be described. (i) UD / C at 1st speed based on the combination of FIG.
4. The duty solenoid valves 22 and 34 are controlled to set Red / B6 to a high pressure, and OD / C2 and 2-5 / B
3 is set to a low pressure so that the duty solenoid valves 12, 18
Control. Therefore, the communication passages 176 and 161 have a high pressure, and the communication passages 175 and 173 have a low pressure.

2, the line pressure is introduced to the left end through the communication passage 170, the OD / C pressure is introduced through the communication passage 171 and the UD / C pressure is introduced through the communication passage 172 in FIG. The OD / C pressure is low and the UD / C pressure is high. Since the pressure receiving area of the fail-safe valve 14 that receives the UD / C pressure is smaller than the left end that receives the line pressure, the balance of the force causes the fail-safe valve 14 to move to the right in FIG.
Communicates with the communication passage 173. Since the pressure in the communication passage 173 is low, 2-5 / B3 is released.

Both pressures in the communication passage 180 and the communication passage 181 are introduced to the right of the first speed determination valve 36 in FIG. The position of the first speed determination valve 36 is determined by the balance between the force received from these two pressures and the urging force of the spring 37. In the case of the first speed, since the pressures in the communication passages 180 and 181 are both low, the first speed determination valve 36 moves rightward by the urging force of the spring 37, and the communication passage 182 becomes drain pressure. As a result, the communication passages 183 and 184 also have a drain pressure.

Since the communication passage 122 is at a drain pressure, the communication passage 185 is also at a drain pressure. Accordingly, the pressure on the right side of the fail-safe valve 24 in FIG. 2 is the drain pressure. Since the communication passage 187 has a line pressure, the left side of the failsafe valve 24 has a high pressure. Therefore, the fail-safe valve 24 moves to the right in FIG. 2, and the communication path 188 communicates with the communication path 189. Here, when the first speed in one range is selected, the duty ratio of the duty solenoid valve 28 is controlled and the communication passage 188 is set to a high pressure, thereby engaging the LR / B5.

The failsafe valve 30 moves to the right by the urging force of the spring 31 because the communication passage 127 and the communication passage 161 have a high pressure. Therefore, the communication path 13
0 becomes the drain pressure, and D / C 7 is released.

(Ii) As shown in FIG. 3, when shifting from the first speed to the second speed, 2-5 / B3 is engaged and LR / B5 is released. When the instruction pressure of the duty solenoid valve 18 is gradually set to a high pressure, the communication path 17
The pressure at 3, 174 also increases and 2-5 / B3 engages.

By increasing the pressure of the communication path 174, the communication path 180 is increased.
Therefore, the first-speed determination valve 36 moves to the left in FIG. Then, the communication passage 182 becomes a line pressure, and the fail-safe valve 24 moves to the left accordingly.
The communication passage 189 has a drain pressure regardless of the pressure of the communication passage 188. Since the pressure in the communication passage 200 is the drain pressure outside the R range, the LR / B5 is released. By switching the fail-safe valve 24, 2-5 / B3 and LR / B
The occurrence of double engagement due to the simultaneous engagement of the five is prevented.

(Iii) As shown in FIG. 3, when shifting from the second speed to the third speed, 2-5 / B3 is released and OD / C2 is engaged. As the shift control, the instruction pressure of the duty solenoid valve 18 is reduced, and at the same time, the instruction pressure of the duty solenoid valve 12 is increased to perform the switching control of the friction element. Then, when the pressure of OD / C2 rises to a pressure equal to the line pressure and the sum of the forces received from the pressure applied to the right side of the fail-safe valve 14 exceeds the sum of the forces received from the pressure applied to the left side of the fail-safe valve 14, Moves to the left to communicate the communication passage 174 with the drain passage 190, and takes measures to prevent double engagement in the event of erroneous control of the duty solenoid valve 18.

The shifting process from the second speed to the third speed will be described in detail. In FIG. 4, _Nt indicates the turbine speed, and Pt
_{OD / C} and P2-5 / B indicate the pressure applied to _{OD / C2} and _2-5 / B3, respectively.

In FIG. 4, the area indicated by 2 indicates the state of the second speed. At time t ₀ , the shift command from the second speed to the third speed is E
Instructed by the CU, P _{2-5 / B} is decreased and P _{OD / C} is increased in the area of _の to perform rapid filling control.
At this time, the pressure of UD / C4 is maintained at the line pressure. After the elapse of the holding period, P _{2-5 / B} is gradually decreased and P _{OD / C} is increased for formation of a torque phase.
Upon entering the inertia-phase, lowering the P _{2-5 / B} to drain pressure, N _t controls the P _{OD / C} so that the ideal slope. _{OD / C} is increased to the line pressure by the end of inertia phase determination. When P _{OD / C} rises to the line pressure, the failsafe valve 14 moves to the left, and the communication path 174 and the communication path 173 communicate. Since P _{2-5 / B} is reduced before the fail-safe valve 14 is switched,
Double engagement of D / C2, 2-5 / B3, and UD / C4 can be reliably prevented.

In the shifting process from the third speed to the second speed, P
_{OD / C} is reduced from the line pressure to the pressure just before release, and P _{2-5 / B} is rapidly charged. When P _{OD / C} is lowered, the fail-safe valve 14 moves to the right, and 2-5 /
After B3 is connected to the control valve 16, quick filling control of 2-5 / B3 is performed.

(Iv) Since the fail-safe valve 24 moves to the left in the state of the third speed, the communication path 188
It communicates with 1. In 1st, 2nd and 3rd speed, Red /
Since the pressure of B6 is high, the fail-safe valve 30 is moving rightward. Therefore, since the communication path 130 and the drain path 131 communicate with each other, the D / C 7 is released. As shown in FIG. 3, when shifting from third speed to fourth speed, Red / B6 is released and D / C 7 is engaged.

Here, the duty ratio of the duty solenoid valve 34 is controlled, and the output pressure of the control valve 32 is slightly reduced within a range where the torque of Red / B6 does not fall below the transmission torque.
Then, the pressure of the communication passage 161 which is the output pressure of the control valve 32 also decreases, and the fail-safe valve 30 moves to the left. Then, the communication passage 191 communicates with the communication passage 130, and the pressure applied to the D / C 7 can be controlled by the duty solenoid valve 28. Therefore, the pressure applied to the D / C 7 is increased, and Red is increased.
The gear shift control is performed by lowering the pressure of / B6 to shift to the fourth speed.

(V) As shown in FIG. 3, when shifting from the fourth speed to the fifth speed, UD / C4 is released and 2-5 / B3 is engaged. When the duty ratio of the duty solenoid valve 22 is controlled and the output pressure of the control valve 20 is slightly reduced within a range where the torque of UD / C4 does not fall below the transmission torque, the fail-safe valve 14 moves to the right. Then, the communication passage 173 is communicated with the communication passage 174, and the duty solenoid valve 18 controls 2-5 / B
3 can be controlled again, so that 2-5 / B
And the pressure of the UD / C4 is decreased, and the transmission is shifted to the fifth speed. The basic shift method in the D range has been described above, but the same shift control is performed in the 4, 3, 2, and 1 ranges.

(3) Next, the R range will be described. When the manual valve 38 is set to the position of the R range, the communication passage 120 communicates with the communication passage 122, and the communication passage 123 communicates with the drain passage 121.
Communicate with When the communication path 122 has a high pressure, R /
The pressure applied to C1 becomes high, and R / C1 is engaged.
Further, the communication passage 185 branched from the communication passage 122 also becomes high pressure, passes through the communication passage 200 branched therefrom, and is applied with line pressure to the LR / B5 via the high pressure selection valve 29 to cause LR / B
5 is engaged. The R range is achieved by increasing the pressure of Red / B6 with the duty solenoid valve 34.

Next, lock-up control will be described. The pressure in the communication passage 106 is controlled by the secondary valve 43.
The pressure is controlled to a certain constant value by the balance of the force between the spring 43a and the communication path 107.

The communication passage 106 communicates with the communication passage 210, communicates with the communication passage 211 via the lock-up relay valve 52, and moves to the left of the lock-up clutch 51.
Hydraulic oil is supplied by 6, and the hydraulic oil passes through the torque converter 50 and is discharged through the communication path 212, the lock-up relay valve 52, the communication path 213, and the oil cooler 46. This is the lock-up off state. A communication passage 184 is provided at the right end of the lock-up relay valve 52.
Is connected, the lock-up relay valve 52 is driven by the output of the first speed determination valve 36. When the pressure applied to OD / C2 and 2-5 / B3 are both low,
In other words, when the shift speed is not any of the second to fifth speeds, the first speed determination valve 36 moves to the right, and the communication path 184 becomes low pressure,
The lock-up relay valve 52 moves to the right. At this time, the on / off solenoid valve 53 is moved to the right. Thus, the lock-up clutch 51 is configured to be released at the first speed.

When either OD / C or 2-5 / B satisfies any of the conditions of 2nd to 5th speed at high pressure, lockup is turned on. The on / off solenoid valve 53 is moved to the left to reduce the pressure in the communication passage 214. Then
The lock-up relay valve 52 moves to the left and the communication passage 21
5 and the communication path 216, and the communication path 212 and the communication path 210 communicate with each other. Here, since the pressure on the left side of the lock-up clutch 51 can be controlled by controlling the command pressure of the duty solenoid valve 55, lock-up slip control and complete lock-up can be realized.

FIG. 5 shows a comparative example of this embodiment. Components that are substantially the same as those of the present embodiment are denoted by the same reference numerals. OD
/ C2, 2-5 / B3, and UD / C4, the fail-safe valve 300 controls the OD /
The pressure applied to C2, 2-5 / B3, and UD / C4 is introduced as the switching pressure. Therefore, the pressure of the communication passage 170 is applied to the failsafe valve 300 to form four different diameter portions, and the structure is more complicated than that of the failsafe valve 14 of the present embodiment.

In the above-described embodiments of the present invention described above, the OD / C2 which generates double engagement when engaged simultaneously,
2-5 / B3 and OD / C4
Only the pressure applied to C2 and UD / C4 is used for switching the fail-safe valve 14. Therefore, 2-5 /
Since it is not necessary to form the pressure receiving surface of the pressure applied to B3 on the fail-safe valve 14, the configuration of the fail-safe valve 14 is simplified, the manufacturing cost is reduced, and the fail-safe valve 14 is easily assembled.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a double engagement prevention circuit according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the automatic transmission according to the embodiment.

FIG. 3 is an explanatory diagram showing engagement or disengagement of a friction element at each shift speed of the embodiment.

FIG. 4 is a time chart showing a shift process from a second speed to a third speed.

FIG. 5 is a hydraulic circuit diagram showing a double engagement prevention circuit according to a comparative example of the present embodiment.

[Explanation of symbols]

 1 R / C 2 OD / C (second friction element) 3 2-5 / B (first friction element) 4 UD / C (second friction element) 5 LR / B 6 Red / B 7 D / C 10 Control Valve (second control means) 12 Duty solenoid valve (second control means) 14 Fail safe valve (switching means) 15 Spring (biasing means) 16 Control valve (first control means) 18 Duty solenoid valve (first control means) 20) Control valve (second control means) 22 Duty solenoid valve (second control means) 40 Hydraulic pump (source pressure generation means) 42 Line pressure control valve (source pressure generation means) 44 Duty solenoid valve (source pressure generation means) 45 pressure reducing control valve (source pressure generating means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masashi Honda 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Sou Yokoyama 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Co., Ltd. Inside DENSO

Claims (5)

[Claims] 1. An automatic transmission control device for shifting gears by engaging or disengaging a plurality of friction elements having at least a first friction element and a second friction element by a hydraulic pressure of a working fluid, wherein the first friction element includes: An element and the second friction element comprising at least one friction element are simultaneously engaged to form a double engagement, and a source pressure generating means for generating a source pressure of a working fluid; A first control unit that controls a hydraulic pressure to be engaged or released; a second control unit that controls a hydraulic pressure to be engaged or released by the second friction element; the original pressure generation unit; and the first friction element. Switching means disposed in a fluid passage connecting the first friction element and a fluid passage connected to the first friction element, wherein a liquid applied to the second friction element of the first friction element and the second friction element is provided. Switching the switching means by pressure Automatic transmission control apparatus according to claim Rukoto. 2. The automatic transmission according to claim 1, wherein the original pressure can be introduced to the switching means so as to press the switching means in a direction opposite to a hydraulic pressure applied to the second friction element. Machine control device. 3. The automatic transmission control according to claim 1, wherein the switching means is a spool valve, and a hydraulic pressure applied to the second friction element is applied to one end of the spool valve. apparatus. 4. The automatic transmission control according to claim 3, wherein there are a plurality of said second friction elements, and one end of said spool valve is formed to have at least two steps of different diameters. apparatus. 5. The apparatus according to claim 2, further comprising an urging means for urging said switching means in a direction in which a hydraulic pressure applied to said second friction element presses said switching means. The automatic transmission control device according to claim 1.