JPS6231754A - Hydrauric circuit for controlling automatic transmission gear - Google Patents

Abstract

PURPOSE:To smoothly perform speed change by making a control valve to reduce the servo pressure of a hydraulic servo to the predetermined pressure prior to the release of the hydraulic valve. CONSTITUTION:A control valve 66 is disposed between a shift valve 53 and a hydraulic servo B0 for controlling a frictional engaging element. Further, the control valve 66 is controlled by the signal supplied from a control means S0 and, in case of drain of a hydraulic servo B0 through the shift valve 53, first of all, the control valve 66 is made to reduce the servo pressure of the hydraulic servo B0 to the predetermined pressure. Owing to this constitution, it is possible to smoothly perform speed change.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a hydraulic circuit for controlling an automatic transmission mounted on an automobile, and more particularly to a drain control mechanism for a hydraulic servo for a frictional engagement element.

(B) Prior Art Generally, an automatic transmission includes a torque converter and a planetary speed change gear mechanism, and the speed change gear mechanism includes an overdrive (0/D) planetary gear unit, a front planetary gear unit, and a rear planetary gear unit. The speed change gear mechanism has two solenoid valves and three shift valves, and predetermined elements thereof are engaged or locked by a clutch or brake (frictional engagement element), resulting in four forward speeds and one reverse speed. It has a gear shift.

Furthermore, conventionally, the frictional engagement element is controlled by a hydraulic servo to which hydraulic pressure is supplied or drained based on switching of the shift valve, but the hydraulic servo has an accumulator installed in parallel. Based on the set hydraulic characteristics, the servo pressure of the hydraulic servo and the engagement characteristics of each friction engagement element are determined, and in particular, the drain characteristics of the accumulator are directly influenced when the servo pressure is released.

Problems to be solved by the invention By the way, the above accumulator has predetermined hydraulic characteristics,
Therefore, it is difficult to control the release of the servo pressure depending on the torque, vehicle speed, or the timing of engagement with other frictional engagement elements.

Particularly recently, automatic transmissions have been devised that achieve multi-speed shifting by complexly combining the engagement operations of clutches and brakes.
In such an automatic transmission, the shift lock becomes a major problem due to the drain characteristics of the accumulator consisting of the above-mentioned predetermined hydraulic characteristics.

For example, if the sub-transmission unit is overdrive or directly connected,
A multi-stage automatic transmission device (Japanese Unexamined Patent Application Publication No. 57-37
140) has been devised, but in this case, there are cases where one of the transmission units performs a downshift operation and the other one performs an upshift operation. Specifically, there are cases where the sub-transmission unit downshifts from overdrive to direct connection, and at the same time the main transmission unit upshifts from 1st gear to 2nd gear, resulting in an overall shift from 2nd gear to 3rd gear. In this case, the conventional control device consisting of a shift valve and an accumulator does not take measures to complete both shift operations at the same time, so there is a risk that one of the shift operations will occur first and then the other shift operation. There is. For example, if a downshift is performed first, the speed will be significantly reduced (1st gear) and then significantly increased (3rd gear), and if an upshift is performed first, the speed will be significantly increased (3rd gear). The speed will be increased (to 4th gear) and then decelerated, causing the engine speed to rise and drop, as well as causing a large shift shift.

Therefore, the present invention aims to control the sliding characteristics of the frictional engagement element at the start of sliding, the sliding process, and the end thereof by controlling the release servo pressure of the hydraulic servo, thereby obtaining smooth shifting characteristics. This is the purpose.

(B) Means for Solving the Problem The present invention has been made in view of the above circumstances, and as shown in FIG. 1 or 2, a hydraulic servo B0 that controls the shift valve 53 and the frictional engagement element A control valve 66 is disposed between the two, and the control valve 66 is controlled by a signal from the control means S0 or S0', 41.
When the shift valve 53 drains the hydraulic servo B0, the control valve 66 first reduces the servo pressure of the hydraulic servo B0 to a predetermined pressure.

- For example, as shown in FIG. 1, the control means includes a duty-controlled solenoid valve S, and the solenoid valve S0 is duty-controlled in accordance with torque, vehicle speed, or engagement timing of other frictional engagement elements. A predetermined reduced pressure is applied to the control oil chamber t2 of the control valve 66.

Further, as another example, as shown in FIG. 2, a solenoid valve S is controlled to be turned on and off by a signal from the control means. ' is the oil pressure and the throttle pressure from the throttle valve 41. The oil pressure from the solenoid valve SD acts on the control oil chamber t2 of the control valve 66, and the throttle pressure acts from the oil chamber X on the spool 66a.

Furthermore, a specific example applied to a multi-stage automatic transmission consisting of a main transmission unit and an auxiliary transmission unit is shown in FIG. Specifically, the B0 release control valve 66 that controls the release pressure of the O/D brake hydraulic servo B0 (hereinafter simply referred to as brake B0, and the same applies to other brakes and clutches) is connected to the O/D brake B0 and the third shift. valve 5
3, and the valve 66 is a solenoid valve S.

, the rotation sensor A2 detects the rotational speed of a predetermined component 30 of the main transmission unit 21 (and the sub transmission unit
A rotation sensor A that detects the rotation speed of a predetermined component 23 of
, ), the upshift operation (for example, from 1st gear to 2nd gear) is performed by engaging the brake B2 of the main transmission unit 21, and the auxiliary transmission unit is controlled by the release of the 0/D brake B0. Synchronize the downshift (0/D → direct connection) operation.

(E) Operation: Control the control valve 66 based on the above configuration! 1
Ill Pressure acting on oil chamber t2 or duty solenoid S. (Fig. 1) or on/off solenoid S. 'The control oil chamber t2 is drained,
When the throttle pressure in the oil chamber X acts on the spool 66a (FIG. 2), the hydraulic servo Bo and the accumulator B are activated. Based on the pressure in the main oil chamber y2 communicating with A, the spool 6
6a is moved above a predetermined distance I, and the port y and the drain boat d are communicated with each other by an appropriate throttle amount. As a result, the servo pressure in the hydraulic servo B0 passes through the boat y and the drain boat d to the solenoid valve S. The release is performed according to the duty amount or the throttle opening, and the sliding state of the w1 frictional retaining element is appropriately controlled. And after that, Schiff 1-
When the valve 53 is switched and the bow 1-o communicates with the drain bow 1-d (left half position), the pressure oil in the hydraulic servo B0 is completely drained through the check valve 72.

Further, to explain a specific example applied to a multi-stage automatic transmission consisting of a main transmission unit and a sub-transmission unit, for example, when the entire transmission 1 shifts from 2nd speed to 3rd speed, the main transmission unit 21 applies the brake B. The auxiliary transmission unit 16 also upshifts from 1st gear to 2nd gear.
is released and clutch C0 is engaged to downshift from O/D to direct connection (see Figures 9 and 10). At this time, modulator pressure is supplied through 65 of the S0 modulator valve. The solenoid valve S is duty-controlled or on-controlled by a signal from the control section E, and the B0 release control valve 66 is turned on.

to control the release operation of O/D brake B0. As a result, when the brake B2 of the main transmission unit 21 is engaged, the opening of the 16 brakes B0 is synchronously controlled in the sub-shift.

Note that the above specific example describes an example applied to a multi-stage automatic transmission consisting of a combination of an O/D planetary gear unit and two planetary gear units, but is not limited to this. A multi-stage automatic transmission consisting of a combination of two planetary gear units, and a split-type automatic transmission consisting of two planetary gear units separated by a clutch etc.
automatic transmission (for example, see Japanese Patent Application Laid-Open No. 59-183147), a four-speed automatic transmission consisting of two planetary gear units other than the split type, and a combination of these four-speed automatic transmissions with O/D or U/ It goes without saying that the present invention can be similarly applied to any automatic transmission having a hydraulic servo, such as a multi-speed transmission in combination with a D planetary gear unit, and even a general three-speed automatic transmission in some cases.

(f) Example Embodiments of the present invention will be described below along with the drawings.

As shown in FIG. 4, the multi-stage automatic transmission 1 includes a torque converter 2, a planetary transmission gear mechanism 3, and a hydraulic control mechanism 5, each of which includes a converter housing 6, a transmission case 7, an extension housing 9, and It is housed in the valve body 10 and oil pan 11. The torque converter 2 is equipped with a lock-up clutch 12, and the rotation of the input member 13 is directly transmitted to the input shaft 15 of the transmission gear mechanism 3 via the oil flow of the torque converter 2 or by the lock-up clutch 12. The transmission gear mechanism 3 includes a sub-transmission unit 16 comprising an overdrive (0/D) planetary gear unit 17, and a main transmission unit 21 comprising a front planetary gear unit 19 and a rear planetary gear unit 20. The 0/D planetary gear unit 17 includes a planetary gear 22 directly connected to the input shaft 15, a sun gear 23 fitted to the input shaft 15, and a ring gear 25 connected to the input shaft 26 of the main transmission unit 21. An O/D direct clutch C0 and a one-way clutch F0 are interposed between the sun gear 22 and the sun gear 23, and an O/D brake B0 is disposed between the sun gear 23 and the case 7. The front planetary gear unit 19 also includes a planetary gear 29 that is directly connected to the output shaft 27, a sun gear 30a that is fitted onto the output shaft 27 and is integrally configured with the sun gear 30b of the planetary gear unit 20, and an input shaft 26. A direct clutch C2 is interposed between the input shaft 26 and the sun gear 30, and a direct clutch C2 is interposed between the sun gear 30 and the case 7. A brake B1 is interposed, and a brake B2 is further provided between the sun gear 30 and the case 7 via a one-way clutch F1. Further, the rear planetary gear unit 20 includes a planetary gear 31, a sun gear 30b, and a ring gear 32 directly connected to the output shaft 27, and a brake B3 and a one-way clutch F2 are arranged in parallel between the planetary gear 31 and the case 7. It is set up.

In addition, 35 in FIG. 2 is an oil pump.

A rotation sensor A1 consisting of a photoelectric sensor or an electromagnetic sensor is installed in the case 7 of the O/D planetary gear unit 17, and a flange piece 23a connected to the sun gear 23 is cut at equal intervals. Therefore, the rotation sensor A1 detects the rotation speed of the sun gear 23, that is, the shift operation state of the sub-transmission unit 16.A rotation sensor A2 is also provided in the case 7 of the front planetary gear unit 19. are installed, and the clutch connecting piece 30c extending from the sun gear 30 is also formed with notches or holes at equal intervals.

Therefore, the rotation sensor A2 detects the rotation speed of the sun gear 30,
That is, the shift operation state of the main transmission unit 21 is detected.

On the other hand, the hydraulic speed change control mechanism 5, as shown in FIG. 5, includes a large number of valves, an accumulator, an orifice 36, a strainer 37, etc., and the pot valve will be described below.

The manual valve 40 is set to P, R, N by the shift lever.
The ranges D, S, and t are selected, and the oil passages a, b, Q, and e are switched as shown in FIG. 6, respectively. Note that line pressure is supplied to the oil passage I. The throttle valve 41 is accompanied by a downshift plug 42, and a cam rotates in response to depression of the accelerator pedal to obtain a throttle pressure corresponding to the engine output. The cutback valve 43 generates cutback pressure in ranges other than 1st speed, reverse, P, and N ranges, and acts on the throttle valve 41 to reduce the throttle pressure. The primary regulator valve 45 is regulated by the throttle pressure and generates line pressure corresponding to the load. That is, when the load is high, the line pressure is increased to ensure the working pressure of the clutches C, brakes B, etc., and when the load is light, the line pressure is regulated to a lower level. The secondary regulator valve 46 is regulated by the hydraulic pressure from the primary regulator valve 45 and controls the converter hydraulic pressure and the lubricating hydraulic pressure supplied to the converter 2 and each lubricating section 47 .

Lock-up relay valve 49 is solenoid valve SL
is controlled to switch the oil flow leading to the lock-up clutch 12 and oil cooler 50. That is, by turning on the solenoid valve SL, line pressure is applied to the upper end oil chamber e', thereby changing the converter hydraulic oil path f whose pressure is regulated by the secondary regulator valve 46 from the lock-up clutch off oil path g to the on oil path. At the same time, the off oil passage g is guided to the drain circuit. The first shift valve 51 is connected to the first and second gears of the main transmission unit 21 (the transmission 1 as a whole
It is operated by a solenoid valve S1. That is, when the solenoid valve SI is turned off, line pressure is applied to the oil chamber i, and the manual valve 40 is turned off.
Line pressure oil path a in range, S range and L range
and by turning on the solenoid valve Sl, the oil passage a is communicated with the oil passage j, and the line pressure is applied to the brakes B2 and B2.
Supplied to accumulator B2A. Second shift valve 5
2 is for switching between 2nd speed and 3rd speed (3rd speed and 5th speed for the entire transmission) of the main transmission unit 21, and is operated by a solenoid valve S2. That is, solenoid valve S2
When the line pressure is turned off, line pressure is applied to the oil chamber k, and the in-pressure oil passage lt
It communicates with oil passage m to supply line pressure to direct clutch C2 and C2 accumulator C2A, and is closed by turning on solenoid valve S. The third shift valve 53 is for switching the sub-transmission unit 16, and is operated by eight solenoid valves. That is, by turning on the solenoid valve S3, line pressure is applied to the oil chamber n, and the line pressure oil passage 1 is communicated with the oil passage 0, and the line pressure is explained later in B. 0/through the release control valve 66
D brake B0 and B0 accumulator B. A, and by turning off solenoid valve S, line pressure oil passage l is communicated with oil passage q, and line pressure is supplied to O/D direct clutches C0 and C. Communicates with accumulator CA. The first coast modulator knob 55 is in the L range of the manual valve 40 (herein, the second shift valve 52
The line pressure of the oil passage 1 supplied through the brake regulator is regulated to the coast modulator pressure, and the coast modulator pressure is further supplied to the brake B3 via the first shift valve 51.

The second coast modulator valve 56 regulates the line pressure of the oil passage 1 supplied via the first shift valve 51 and the second lift valve 52 to the coast modulator pressure in the S range of the manual valve 40, and Supplies coast modulator pressure to brake B. By supplying throttle pressure to the oil chamber r, the first accumulator controller 1 to the roll valve 57 regulate the hydraulic pressure supplied via the second accumulator control valve 70 (described later) to the accumulator control pressure. Control pressure is B. Accumulator B. Each back pressure chamber 59 of A, C2 accumulator C2A and B2 accumulator B2A
, 60, 61.

Furthermore, each oil pressure is 41!1! In addition to the IPJ, the present hydraulic shift control mechanism 5 includes a So modulator valve 65. B.

Release control valve 66, Bo sequence valve 67, lock-up control valve 69 and second
An accumulator control valve 70 is attached.

As shown in detail in FIG. 3, the S modulator valve 65 is supplied with line pressure from the line pressure boat t via the oil strainer 37, and is further communicated with the upper end oil chamber Sl via the oil passage S. The feedback pressure acting on the oil chamber S1 and the spring 71 are balanced and regulated to a predetermined pressure (for example, 4 kg/c+Ir), and the regulated solenoid module pressure is further supplied to the oil passage t. Furthermore, the oil path is connected to the solenoid valve S via the plug 72 and the oil path t1.

It also communicates with the B0 release control valve 66, which is a solenoid valve S.

Control pressure by on/off control or duty control is supplied to the oil chamber L2, and the control valve 66 is controlled. In addition, solenoid valve S. is rotation sensor A,
Although it is controlled by a signal from the control unit E based on A2,
When the valve S0 is under on/off control, a throttle pressure is supplied to the boat X, and a brake release pressure is set according to the throttle opening. Furthermore, said B. The boat y of the release control valve 66 is connected to the O/D brake Bo and the B0 accumulator B via the oil path y. A, and also communicates with the lower end oil chamber y2 via the orifice 36 as feedback pressure. In addition, the oil path y1
is brake B. and accumulator B. It communicates with the bypass path y5 in the direction of the tip of A, and the bypass path u y
, and communicates with the boat y3 of the hash sequence valve 67, and further communicates with the lower end oil chamber y4 of the valve 67 as feedback pressure. Note that the feedback pressure in the oil chamber 4 is balanced with the spring 80 at the upper end, and the spring 80 is the O/D brake B. The piston initial operating pressure is set at which the brake plates of
Therefore, the sequence valve 67 is in the left half position until the initial operating pressure is reached, and hydraulic pressure is supplied to the O/D brake through the boats Z2 and y3, and when the initial operating pressure is exceeded, the sequence valve 67 is in the left half position. , and boats z2 and y3 are blocked. Further, the boat z of the control valve 66 is connected to the third shift valve 53 via the oil passage Z and the orifice 36.
B via a bypass path Z5.

The oil passage y6, which is connected to the boat z2 of the sequence valve 67 and branched from the oil passage y, is connected to the check valve 72.
It communicates with oil passage Z via. On the other hand, the upper chamber n of the third shift valve 53 communicates with the solenoid valve S3, the port l communicates with the line pressure, and the port lq communicates with the 0/D via the oil passage q1 and the orifice 36. It communicates with the direct clutch C0 and the C0 accumulator CoA. Note that a check valve 75 is interposed in parallel with the orifice 36 of the oil passage q to allow discharge from the clutch C0. Further, d in the figure is a drain port.

In addition to the conventional control that enables lock-up when the main transmission unit 21 is in 2nd gear or higher, the lock-up control valve 69 also controls the sub-transmission unit 16 to be in the 0/D state even when the main transmission unit 21 is in 1st gear. In other words, when the transmission as a whole is in second gear or higher, control is performed so that lockup is possible. Further, the second accumulator control valve 70 is configured such that the sub-transmission unit 16 is
When the main transmission unit 21 upshifts in the D state, the main transmission brake capacity becomes excessive compared to the case where the auxiliary transmission unit 1G is directly connected. A, C2A, B2A back pressure chambers 59, 60.6
This is to reduce the pressure supplied to 1 and optimize the brake capacity.

Next, the operation of this embodiment will be explained.

Each solenoid valve S of the present multi-stage automatic transmission 1.

s2. s3. sL, so, each clutch C0, C,, C2
, brake B. j Bll B3, and each one-way clutch F0. F,, F2 are each position P, R
,N,D.

The S and L gears are controlled as shown in the operation table shown in FIG. 7, respectively.

That is, in 1st speed in D range or S range, as shown in FIG. 8, O/D direct clutch C0 and one-way clutch F. , F2 and forward clutch C1
are engaged, and the others are in a released state.

Therefore, the sub-transmission unit 16 is connected to the planetary gear unit 1 via the clutch C0 and the one-way clutch F0.
7 are integrated into a directly connected state, and the rotation of the input shaft 15 is directly transmitted to the input shaft 26 of the main transmission unit 21. Further, in the main transmission unit 21, the rotation of the input shaft 26 is transmitted via the clutch C to the ring gear 33 of the front planetary gear unit 19, and further transmitted to the planetary gear 29 and the output shaft 27 integrated with the gear 29. A leftward revolution force is applied to the planetary gear 31 of the rear planetary gear unit 20 through the gear 30, but the revolution is prevented by the one-way clutch F, and the gear 31 rotates to the ring gear 3 integrated with the output shaft 27.
Power is transmitted to 2. That is, the main transmission unit 21 is in the 1st speed state, and together with the directly connected state of the auxiliary transmission unit 16, the entire transmission is in the 1st speed state. At this time, the main transmission unit 21 is branched into two systems, from the front planetary gear unit 19 to the output shaft 27 and from the rear planetary gear unit 20 to the output shaft 27, thereby distributing the load received by the gears. .

Further, in the second speed in the D range or the S range, as shown in FIG. 9, the 0/D brake B0, one-way clutch F2, and forward clutch C8 are engaged, and the others are in a released state. Therefore, in the sub-transmission unit 16, the sun gear 23 is locked by the brake B0, the planetary gear 22 rotates and transmits power to the ring gear 25, and the input shaft 26 of the main transmission unit 21 is rotated at an increased speed (
0/D). Furthermore, the main transmission unit 21 is in the same state as the first speed, so the first speed of the main transmission unit 21 and the speed increase of the sub-transmission unit 16 combine to bring the entire transmission into the second speed state.

At this time, as shown in FIG. 3, the solenoid valve S3 is turned on, and line pressure is supplied to the oil chamber n of the third shift valve 53, so that the third shift valve 53 is switched to the state shown in the left half diagram. Then, the pressure oil in clutch C0 and C0 accumulator C0A is discharged from port q to drain port d, clutch C6 is released, and line pressure port 4 communicates with port 0.

The line pressure from port 0 is the port z2p of the sequence valve 67 until the initial operating pressure of the B0 piston is reached.
It is directly supplied to the 0/D brake B0 via Y3 and oil passage y5, and when the initial operating pressure of the B0 piston is exceeded, the oil chamber y
The valve 67 is switched to the left half position based on the feedback pressure of the B release control valve 66, and then the line pressure from the port 0 is supplied to the port 2 of the B release control valve 66 via the orifice 36 and the oil passage Z. Furthermore, in this state, the control valve 66 is in the left half position, port 2 and y are in communication, and line pressure is applied to the brakes B0 and B via the oil path yl. Accumulator B. supplied to A,
Engage brake B.

In addition, when in the D range and the third speed, as shown in Fig. 10, the 0/D clutch C8, one-way clutch F0, forward clutch C11, one-way clutch F1, and brake B2 are engaged, and the others are in the released state. . Therefore, the sub-transmission unit 16 is in the above-mentioned direct connection state, and the rotation of the input shaft 15 is directly transmitted to the input shaft 26 of the main transmission unit 21.
transmitted to.

Further, in the main transmission unit 21, the rotation of the input shaft 26 is transmitted to the ring gear 31 of the front gear unit 31 via the clutch C, and the rotation of the input shaft 26 is transmitted to the ring gear 31 of the front gear unit 31 via the planetary gear 29.
However, the sun gear 30 is prevented from rotating in this direction by the one-way clutch F when the brake B2 is engaged, and therefore the planetary gear 29 revolves while rotating, and the front gear unit The second speed rotation is transmitted to the output shaft 27 only via 29. As a result, the direct connection state of the sub-transmission unit I-16 and the direct connection state of the sub-transmission unit I-16 and the
Together with the second speed state of 21, the third speed can be obtained for the transmission 1 as a whole.

At this time, the solenoid valve S is turned on and the first shift valve 51 is switched to the left half position in FIG.
is communicated with port J to supply line pressure to brake B2 and accumulator B2A.

The resulting shift state of the main transmission unit 21, that is, the rotational change of the sun gear 30, is monitored by the rotation sensor A2, and upon receiving an electric signal from the control unit E accompanying the start of the rotational change, the B0 release controller and roll solenoid valve S . is duty-controlled to reduce the modulator pressure in the oil passage t. That is, the So modulator valve 65 regulates the line pressure of the line boat L using the spring 71 and the feedback pressure of the main oil chamber S and supplies it to the oil passage t, but the modulator pressure controls the duty of the solenoid valve S0. B, which is depressurized by and communicates with the oil passage t. The pressure in the main oil chamber t2 of the release control valve 66 is also reduced. Therefore, the control valve 66 has its main oil chamber y
, brake B. The brake B0 and accumulator B move to the left half position in Figure 1 while receiving feedback pressure from the brake B0 and accumulator B. Hydraulic pressure from A is discharged to drain port d via oil path y□ and port y. As a result, the main transmission unit 21 detects the deceleration state of the sun gear 30 due to the engagement of the brake B2 using the rotation sensor A, and at the same time, the sub-transmission unit 16 detects the speed increase state due to the release of the brake B0 using the rotation sensor A. These re-rotation sensors A
The release pressure of the O/D brake B is controlled by duty-controlling the solenoid valve S according to a signal from the control unit E based on 1°A. The releasing operation of brake B2 corresponds to the engaging operation of brake B2. That is, as shown in FIG. 15, when the rotation of the sun gear 30 in the main transmission unit 21 decelerates due to the start of engagement of the brake B2, the deceleration state is monitored by the rotation sensor A2, and at the same time, the rotation of the sun gear 30 in the main transmission unit 21 is decelerated. Solenoid S is monitored while rotating the speed increase state of sun gear 23 using rotation sensor A. O/D brake B by controlling the duty. At the point when the main transmission brake B2 is fully engaged and the rotation of the sun gear 30 stops (at L-, the auxiliary transmission brake B0 is controlled to be fully released, and the auxiliary transmission brake B2 is The speed changes of the speed change units 16 and 21 are made to match.At this time, the rotation sensor A2 detects the completion of the speed change of the main speed change unit 21, that is, the rotation of the sun gear 30 has stopped, and the five solenoid valves are turned off by an electric signal from the control unit E. Then, the third shift valve 53 is switched to the left half position in FIG. Pressure is sent, the clutch C6 is engaged, and the port 0
communicates with the drain boat d, and transfers the oil pressure of the 0/D brake B0 to the oil path y6. Check valve 72 and oil path Z.

Then, the drain port 1-d is immediately and completely drained through port 0, and the shift of the sub-transmission unit 16 is completed. In this way, the main transmission unit 21 and the auxiliary transmission unit 16 are synchronized and smoothly shifted.

Furthermore, at this time, solenoid valve S. causes malfunction,
If the B0 release control valve 66 sticks and is fixed at the position shown in the left half of Figure 3, and the port y does not communicate with the drain port d, the pressure oil in the brake B0 will flow through ports y and 2. gZ, and from the check valve 72 that is opened during draining to the oil path 2. Further, when the solenoid valve S3 is turned off and the third shift valve 53 is in the third right half position, it is discharged from the port o to the drain port d. Therefore, even if the valve malfunctions, the 0/D brake B. Line pressure is supplied to both the clutch C0 and the clutch C0, and the O/D planetary gear unit 17 will not be locked, which is safe.

Furthermore, in the 4th gear in the D range, as shown in FIG. 11, the 0/D brake B0, forward clutch C2, brake B2, and one-way clutch F are applied.

are engaged and the others are in a released state. Therefore, the auxiliary transmission unit 16 is in the above-mentioned speed increase to/D) state, and the main transmission unit 21 is in the 2nd speed state, so that the transmission 1 as a whole can obtain 4th speed.

Furthermore, at 5th speed in D range, as shown in FIG. 12, O/D clutch C0 and one-way clutch F. , forward clutch CI, direct clutch C2, and brake B2 are engaged, and the others are in a released state. Therefore, the auxiliary transmission unit 16 is in the above-mentioned directly connected state, and the main transmission unit 21 is integrated with the front planetary gear unit 19 by engagement of the clutches C, C2.
The rotation of the input shaft 26 is directly transmitted to the output shaft 27.

As a result, the direct connection of the sub-transmission unit 16 and the third speed of the main transmission unit 21 combine to provide a fifth speed in which the input shaft 15 and the output shaft 27 rotate integrally as a whole of the transmission 1.

At this time, similarly to the shift from 2nd speed to 3rd speed described above, the speed change state of the main transmission unit 21, that is, the rotational speed of the sun gear 30, is monitored by the rotation sensor A2, and the control unit based on the sensor A2 By the signal from E, solenoid valve S
0/D brake B by controlling the B0 release control valve 66.

The solenoid valve S controls the release state of the auxiliary transmission unit 16 and synchronizes the speed change of the sub-transmission unit 16 with the speed change of the main transmission unit 21 based on signals from the re-rotation sensors A, .
0 to control the hydraulic pressure of brake B0, and further solenoid valve S. Turn off to complete the gear shift and shift smoothly.

Further, at the 6th speed in the D range, as shown in FIG. 13, the O/D brake B0, forward clutch C1, direct clutch C2, and brake B2 are engaged, and the others are in a released state. Therefore, the sub-transmission unit 16 is in the above-mentioned direct connection state, and the main transmission unit 21 is also in the above-mentioned 3rd speed state, and both transmission units 16, 21
Together, 6 speeds can be obtained as a whole for shift B&1.

Further, at R Reno 2, as shown in FIG. 14, the O/D clutch C8, one-way clutch F0, direct clutch C2, and brake B3 are engaged, and the others are in the released state. Therefore, the auxiliary transmission unit 16 is in a directly coupled state, and the main transmission unit 21 has the rotation of the input shaft 26 directly transmitted to the sun gear 30 by the clutch C2, and the revolution of the rear planetary gear 31 is locked by the brake B3. , the rotation of the sun gear 30 is caused by the planetary gear 31.
The reverse rotation is transmitted to the link gear 32 through the rotation of the rotation axis, and the output shaft 27 is rotated in the reverse direction.

Also, in the 3rd and 4th speeds in the S range or L range, in the 3rd and 4th speeds in the D range (10th
11) and coast brake B are engaged, so rotation of the sun gear 30 is prevented in both directions and engine braking is enabled. At this time, when shifting from 2nd speed to 3rd speed, solenoid valve S is activated as in the D range.

is controlled so that the sub-transmission unit 16 and the main transmission unit 21
are shifted simultaneously.

Also, when in 1st and 2nd speed in L range, in 1st and 2nd speed in D range (see Figures 8 and 9).
, brake B3 is engaged, and therefore the revolution of the rear planetary gear 31 is prevented in both directions, making engine braking possible.

In the above embodiment, as shown in FIG. 16, rotation sensors A, A2 are installed in both the sub-transmission unit 16 and the main transmission unit 21, and the solenoid valve S0 is operated while monitoring the rotation of both units. The solenoid valve S is controlled in accordance with the rotation of the main transmission unit 21, as shown in FIG. It may be configured to control on/off.

Further, in the above embodiment, a longitudinally mounted automatic transmission for rear wheel drive in which the sub-transmission unit 16 is located at the front stage and the main transmission unit 21 is located at the rear stage is described. Of course, the present invention can also be similarly applied to a front-wheel drive horizontal automatic transmission in which the transmission unit 1- is located at the rear stage.

(g) As described in detail, according to the present invention, when the shift valve releases the hydraulic servo, the control valve 66 first reduces the servo pressure of the hydraulic servo to a predetermined pressure, so that the hydraulic servo is released. The pressure can be controlled according to the torque, vehicle speed, or the timing of engagement with other frictional engagement elements without being restricted by the hydraulic characteristics of the yJ16 engagement element, and the slippage of the yJ16 engagement element can be controlled. Smooth gear shifting can be achieved by controlling the slip characteristics at the start, the slip process, and the end.

In addition, the control valve 66 is a solenoid valve S that is duty-controlled. When controlled by hydraulic pressure from
It becomes possible to flexibly set the slip start pressure of the 9-maintenance inspection element and the oil pressure in the excessive state, and fine control can be performed according to the characteristics of the automatic transmission and the driving state.

Furthermore, the control valve 66 is a solenoid valve S that is controlled to turn on and off. When controlled by the oil pressure and throttle pressure from ', the sliding pressure of the frictional engagement element can be set in accordance with the torque while having a simple (and highly reliable) structure.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a hydraulic braking circuit for an automatic transmission as an example of the present invention, FIG. 2 is a similar diagram showing another example, and FIG. It is a figure which shows the specific example applied to the multistage transmission which consists of. and,
Figure 4 is an overall sectional view showing an automatic transmission to which the present invention is applied, Figure 5 is an overall view showing its hydraulic control mechanism, Figure 6 is a diagram showing its manual valve, and Figure 7 is each device at each position. It is a figure showing the operating state of. Further, FIGS. 8 to 14 are diagrams showing the operation of the automatic transmission in different states. Furthermore, FIG. 15 is a diagram showing the shift operation of the sub-transmission unit and the main transmission unit, and FIG.
The figure is a block diagram showing one embodiment of the present invention, and FIG. 17 is a block diagram showing another embodiment. 1... (multi-stage) automatic transmission, 2... torque converter, 3... (planetary) speed change gear mechanism, 5
...Hydraulic control mechanism, 16...Sub-transmission unit, 1
7... Overdrive planetary gear unit, 19
...Front planetary gear unit, 20 Rear planetary gear unit, 21...Main transmission unit
,'51,52,53-...shift valve,
53... (3rd) shift valve, 65... S modulator valve, 66... (B. release) control valve, 66a "spool", A12A2... rotation sensor, Bo. B2. B,... friction member Matching element (brake), Bo・
・・Predetermined frictional engagement element (0/D brake), co, C
1, C2...Friction engagement element (clutch), E...Control unit, s,, s2. s3. sL, s. -Solenoid valve, S... Solenoid valve, zp
'l...po 1'', t2p Y2p ''oil chamber. Applicant: Aisin Warner Co., Ltd. Toyota Motor Corporation

Claims (3)

[Claims] (1) Hydraulic pressure for automatic transmission control, which is equipped with a frictional engagement element that engages or locks a predetermined element of the transmission gear mechanism, and further includes a shift valve that supplies and drains hydraulic pressure to a hydraulic servo that controls the frictional engagement element. In the circuit, a control valve is disposed between the shift valve and the hydraulic servo, and the control valve is controlled by a signal from a control means, so that when the shift valve drains the hydraulic servo, the control valve is first controlled. A hydraulic circuit for controlling an automatic transmission, characterized in that the servo pressure of the hydraulic servo is reduced to a predetermined pressure. (2) The hydraulic circuit for automatic transmission control according to claim 1, wherein the signal from the control means is a hydraulic pressure from a solenoid valve whose duty is controlled. (3) The hydraulic circuit for automatic transmission control according to claim 1, wherein the signal from the control means is a hydraulic pressure from a solenoid valve and a throttle pressure from a throttle valve, which are controlled on and off.