JPS62127552A - Liquid pressure control device for automatic transmission - Google Patents

Abstract

PURPOSE:To sharply reduce production of shock during transmission, by a method wherein the shifting time of a transmission gear is detected, and a variable orifice mechanism is shifted and controlled according to the running conditions of a vehicle. CONSTITUTION:Outputs from a car speed sensor 201 and a throttle opening sensor 202 are inputted to a computer 200 controlling first, second, and third shift solenoids 42, 44, and 60, and a 3-2 timing valve 48 being a variable orifice mechanism is controlled by the third shift solenoid 60 according to running conditions. Since the fastening or the releasing timing of a friction element B/B determined according to a pass amount of working fluid can be obtained in an optimum state matching a running condition, this constitution enables sharp reduction of transmission shock due to shifting of the friction element B/B.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pressure control device for an automatic transmission, and more particularly to a hydraulic pressure control device for controlling the actuation timing of a friction element for changing gears in a gear train. Conventional technology Generally speaking, automatic transmissions are manufactured using the 198
4th edition maintenance manual “Automatic Transaxle”
As shown in the figure, a multi-disc clutch is used to switch gear trains using planetary gears, etc. This is done through a plurality of friction elements such as brake bands, and these friction elements are engaged and disengaged by hydraulic fluid supplied from a hydraulic pressure control device. For example, as shown in FIG. 7, a band brake a, which is one of the friction elements, is operated by a band servo b. That is, the band servo b is separated into a fastening pressure chamber e and a releasing pressure chamber f by a servo piston d to which a stem C is fixed, and by supplying hydraulic pressure (fastening pressure) to the fastening pressure chamber e, the above-mentioned As the servo piston d rises, the stem C is pressed and the band brake a is engaged. On the other hand, in a state where the engagement pressure is supplied to the engagement pressure chamber e, hydraulic pressure (release pressure) is supplied to the release pressure chamber f, and due to the difference in pressure receiving areas on both sides of the servo piston d, moves toward the engagement pressure chamber e, and the band brake a is released. Note that g is an accumulator chamber. In the conventional automatic transmission described above, engagement pressure is supplied during second gear to engage band brake a, and release pressure is supplied during third gear to release band brake a. There is. Therefore, when shifting down from third speed to second speed, the release pressure is removed from the release pressure chamber f. By the way, in the circuit h from which the release pressure is removed (common with the release pressure supply circuit), first and second orifices i and j are arranged in parallel, as shown in FIG.
By providing a timing valve k that is switched open and closed depending on the vehicle speed (governor pressure), the releasing speed of the release pressure can be changed between low speed and high speed. That is, when downshifting, the engine speed increases in a short time at low speeds, but it takes a certain amount of time for the engine speed to increase at high speeds. In consideration of this, it is desirable to delay the release speed of the release pressure when downshifting at a vehicle speed higher than a specified speed, so that a smooth gear shift can be performed temporarily in a neutral state. Therefore, at low speeds, by opening the timing valve k, the first. The amount of hydraulic fluid passing through the second orifices i and j increases, and the release pressure is quickly removed, and at high speed, the timing valve k is closed, so the amount of hydraulic fluid passing through only the second orifice j is reduced. The release pressure is removed slowly. Problems to be Solved by the Invention However, in such a conventional hydraulic control device,
The speed at which the release pressure is released, that is, the amount of hydraulic fluid passing through, is set either high or low by switching the opening and closing of the timing valve, but in reality, the vehicle speed is variable steplessly. Therefore, when downshifting is performed at a speed intermediate between low speed and high speed, there is a problem in that optimum tuning becomes difficult and a shift shock occurs. Therefore, the present invention does not fix the amount of hydraulic fluid passing at either a large or small amount, but further finely adjusts the amount of hydraulic fluid passing during gear shifting, that is, during friction element switching operation, depending on driving conditions. An object of the present invention is to provide a hydraulic pressure control device for an automatic transmission that optimally tunes the operation timing of a friction element. Means for Solving the Problems In order to achieve the above object, the hydraulic pressure control device for an automatic transmission of the present invention has the following features: An automatic transmission comprising a friction element for switching, a variable orifice mechanism provided in the circuit, and controlling the switching of the variable orifice mechanism to change the amount of hydraulic fluid supplied to the friction element. The present invention is constructed by providing a control means for detecting when the transmission gear is changed and controlling switching of the variable orifice mechanism according to vehicle running conditions. Effects With the above configuration, in the present invention, the variable orifice mechanism is controlled by the control means according to the driving conditions when changing gears, and the friction element that determines the gear shift timing is substantially engaged or released. The amount of hydraulic fluid passing at the instant of is optimally tuned, and the shift timing is controlled more precisely. EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings. That is, FIG. 1 shows an overall circuit showing an embodiment/example of the hydraulic pressure control device of the present invention, and the power transmission train of an automatic transmission controlled by this hydraulic pressure control device may be, for example, the schematic diagram shown in FIG. 2. There is something like the one shown in the figure. That is, this power transmission train includes a torque converter 3 that transmits the rotation of the engine output shaft 1 to the input shaft 2, a first planetary gear set 4, a second planetary gear set 5, an output shaft 6, and various friction elements described below. Consisting of: The torque converter 3 is driven by the engine output shaft 1 and includes a pump impeller 3P that is also used to drive the oil pump O/P, and a turbine that is fluidly driven by the pump impeller via internal working fluid and transmits power to the input shaft 2. The stator 3S is placed on a fixed shaft via a runner 3T and a one-way clutch 7, and increases torque to the turbine runner 3T.
This is a normal lock-up torque converter with L added. The torque converter 3 receives working fluid from the release chamber 3R, and while the working fluid is removed from the apply chamber 3A, the lock-up clutch 3L is released and the engine power is transferred through the pump impeller 3P and three turbine launches. Torque is transmitted to the input shaft 2 while increasing (in the converter state), and while the working fluid is supplied from the apply chamber 3A and the working fluid is removed from the release chamber 3R, the lock-up clutch 3L is engaged and the engine is activated. It is assumed that the power is directly transmitted to the input shaft 2 via this lock-up clutch (in a locked-up state). In addition, in the latter lock-up state, the slip of the lock-up torque converter 3 (relative rotation of the pump impeller 3P and the turbine runner 3T) can be arbitrarily controlled (slip control) by reducing the working fluid displacement pressure from the release chamber 3R. can do. The first planetary gear set 4 includes a sun gear 4S and a ring gear 4R. The second planetary gear set 5 is a simple planetary gear set consisting of a sun gear 5S, a ring gear 5R, a binion 5P, and a carrier 5C. As a group. Next, the various friction elements mentioned above will be explained. The carrier 4C can be connected to the input shaft 2 via a high clutch H/C, and the sun gear 4S can be connected to the input shaft 2 by a reverse clutch R/C. Can be combined as appropriate. Further, the carrier 4C can be appropriately fixed by a multi-disc low reverse brake LR/H, and is prevented from being reversed (rotation in the opposite direction to the engine) via a row one-way clutch LO/C. The ring gear 4R is integrally coupled to the carrier 5C and drivingly coupled to the output shaft 6, and the sun gear 5S is coupled to the input shaft 2. The ring gear 5R can be appropriately connected to the carrier 4C via an overrun clutch OR/C, and is also correlated to the carrier 4C via a forward one-way clutch FO/C and a forward clutch F/C. Forward one-way clutch PO/C connects ring gear 5R to carrier 4C in the reverse direction (direction opposite to engine rotation) when forward clutch F/C is engaged. High clutch H/C, reverse clutch R/C, low reverse brake LR/B, overrun clutch OR
/C and forward clutch F/C are respectively operated by hydraulic pressure supply to perform the above-mentioned appropriate coupling and fixing, but band brake B/B is connected to 2nd speed servo apply chamber 2S and 3rd speed servo release chamber. When 3S/R and 4th gear servo apply chamber 4S/A are set and 2nd gear selection pressure P2 is supplied to 2nd gear servo apply chamber 2S/A, band brake B/B is activated, and in this state, 3rd gear When the 3rd speed selection pressure P, 3 is also supplied to the servo release chamber 3S/R, the band brake B/B becomes inactive, and then the 4th speed selection pressure P4 is also supplied to the 4th speed servo apply chamber 4S/A. Then, the band brake B/B is activated. Such a power transmission train includes friction elements B/B, H/C, F/C
. By operating OR/C, LR/B, and R/C in various combinations as shown in the table below, the friction elements FO/C, L
Together with the appropriate differential of the O/C, the rotational state of the elements constituting the planetary gear set 4.5 can be changed, thereby changing the rotational speed of the output side relative to the rotational speed of the human power shaft 2,
As shown in the following table, it is possible to obtain four forward speeds and one reverse speed. In the table below, the ○ mark indicates operation (hydraulic inflow), but the ., :: mark indicates a friction element that should be activated when engine braking is required. Then, while the overrun clutch OR/C is operated, the forward one-way clutch FO/C placed parallel to it is inactive, and the low reverse brake is applied while the R/B is operated. Of course, the row one-way clutch LO/C arranged in parallel becomes inoperative. Table 1 with blank space below By the way, the hydraulic pressure side control device shown in FIG.
, torque converter regulator valve 28, lock-up control valve 30, shuttle valve 32, duty solenoid 34, manual valve 36, first shift valve 38, second shift valve 40, first shift solenoid 42, second shift solenoid 44, Forward clutch control valve 46. 3-2 timing valve 48. 4-2 relay valve 50.
4-2 Sequence valve 52, ■ Range pressure reducing valve 54,
Yattle valve 56, overrun clutch control valve 5
8. Third shift solenoid 60, overrun clutch pressure reducing valve 63. 2nd speed servo apply pressure accumulator 64
．． The main components are a 3-speed servo release pressure accumulator 66, a 4-speed servo apply pressure accumulator 68, and an accumulator control valve 70, which are connected to the torque converter 3, forward clutch F/C,
The high clutch H/C1 band brake B/B, reverse clutch R/C low reverse brake LR/B, overrun clutch OR/C1 and oil pump O/P are connected as shown in the figure. The pressure regulator valve 2o includes a spool 20b elastically supported in the left half position in the figure by a spring 20a, and a plug 20c that abuts against the lower end surface of the spool in the figure. Basically, the oil pump O/P is connected to the circuit 71. The oil discharged to the line is regulated to a pressure determined by the spring force of the spring 20a, but when the upward force in the figure is applied to the spool 20b by the plug 20c, the above pressure is increased by that amount to reach the predetermined line pressure. It is something. For this purpose, the pressure regulator valve 20 is connected to the circuit 71 via a damping orifice 72.
Boats 20e to 20h are provided so that the pressure inside the spool 20b is received by a pressure receiving surface 20d of the spool 20b, thereby urging the spool 20b downward, and the boats 20e to 20h are opened and closed according to the stroke position of the spool 20b. The boat 20e is connected to the circuit 71 and arranged so that as the spool 20b descends from the left half position in the figure, it communicates with the boats 20h and 2Of. As the spool 20b of the boat 2Of descends from the left half position in the figure, communication with the boat 20g, which is used as a drain port, decreases, and at the point when communication with this is cut off, the boat 20
Place it so that it begins to communicate with e. and boat 20f
is connected to the capacity control actuator 75 of the oil pump O/P via a circuit 74 with a bleed 73 in the middle. The oil pump O/P is a variable capacity vane pump driven by the engine as described above, and the eccentric displacement is controlled by the actuator 7.
It is assumed that when the pressure toward 5 exceeds a value, the capacity is reduced. The plug 20c of the pressure regulator valve 20 receives modifier pressure from the circuit 76 on its lower end face in the figure, and receives backward selection pressure from the circuit 77 on its pressure receiving surface 20i, and generates an upward force in the figure corresponding to these pressures. Spool 20b
shall be added to. The pressure regulator valve 20 is normally in the left half state in the figure, and when oil is discharged from the oil pump O/P, this oil flows into the circuit 71. Spool 2
At the left half position of 0b, the oil in the circuit 71 is not drained and the pressure increases. This pressure acts on the pressure receiving surface 20d through the orifice 72, pushes down the spool 20b against the spring 2Qa, and connects the boat 20e to the boat 20h. As a result, the above pressure is partially drained from the boat 20h and lowered, and the spool 20b is pushed back by the spring 20a. By repeating this action, the pressure regulator valve 2o basically sets the pressure within the circuit 71 (hereinafter referred to as line pressure) to a value corresponding to the spring force of the spring 20a-. Incidentally, an upward force due to the modifier pressure from the circuit 76 acts on the plug 20c, causing the plug 20c to come into contact with the spool 20b as shown in the right half of the figure, and this upward force causes the spool 20b to support the spring 20a. as well as,
Furthermore, as described below, the modifier pressure occurs when the reverse is not selected and increases in proportion to the engine load (engine output torque), so the above line pressure increases as the engine load increases except when the reverse is selected. Become. When reversing is selected, an upward force is applied to the plug 20c by the retracting selection pressure (same value as the line pressure) from the circuit 77 instead of the modifier pressure, and this is applied to the spool 20b, so that the line pressure remains at the desired constant level when reversing is selected. value. When the rotational speed of the oil pump 0/P reaches or exceeds the rotational speed of the engine (or higher than the rotational speed of the engine), the oil discharge amount that increases accordingly becomes excessive, and the pressure in the circuit 71 exceeds the pressure regulation value. This pressure lowers the spool 20b further from the pressure regulating position in the right half of the figure, and connects the boat 2Of to the boat 1-20e.
Shut off from drain boat 20g. This allows boat 2
(A portion of the oil at le is removed from the port 20f and the bleed 73, but a feedback pressure is generated in the circuit 74. This feedback pressure increases as the rotation speed of the oil pump O/P increases, and the actuator 75 Reduce the eccentricity (capacity) of the oil pump O/P through the oil pump O/P.Thus, the oil pump O/P is controlled so that the discharge amount remains constant while the rotational speed exceeds the value that the oil pump O/P requires. The power loss of the engine is prevented from increasing due to the above discharge.The line pressure generated in the circuit 71 as described above is transmitted to the pilot valve 26, manual valve 36, accumulator control valve 70, and 3-speed servo release via the line pressure circuit 78. The pressure is supplied to the pressure accumulator 66. The pilot valve 26 is equipped with a spool 26b elastically supported in the upper half position in the figure by a spring 26a, and the end face of the spool 28b far from the spring 26a faces the chamber 26c. Furthermore, a drain boat 26d is provided, and a pilot pressure circuit 79 having a strainer S/T is maintained.A communication hole 26e is provided in the spool 26b, and the pressure of the pilot pressure circuit 79 is guided to the chamber 26c, and the pressure of the pilot pressure circuit 79 is guided to the right in the figure. As the process progresses, the circuit 79 is connected to the drain boat 26 from the circuit 78.
It shall be switched and connected to d. The pilot valve 26 is normally in the upper half state in the figure, and when it is supplied with line pressure from the circuit 78, it increases the pressure in the circuit 79. The pressure in the circuit 79 reaches the chamber 241C through the communication hole 26e, causing the spool 26b to move to the right in the figure, and when the spool 26b exceeds the pressure regulating position shown in the lower half, the circuit 79 is cut off from the circuit 78, and at the same time the drain boat 26d is moved. Leads to. At this time, the pressure in circuit 79 is reduced,
When the spool 26b is pushed back by the spring 26a due to this pressure drop, the pressure in the circuit 79 increases again. Pilot valve 26 thus directs line pressure from circuit 78 to spring 26a.
The pressure can be reduced to a constant value determined by the spring force and output to the circuit 79 as pilot pressure. This pilot pressure is transmitted through a circuit 79 to the pressure modifier valve 22, the duty node 24, 34, the lockup control valve 30, the forward clutch control valve 46, the shuttle valve 32, the first . Supplies the second and third shift solenoids 42, 44, 60 and shuttle valve 56. The duty solenoid 24 includes a coil 24a, a spring 24d, and a plunger 24b, and has an orifice 80.
The circuit 81 connected to the pilot pressure circuit 79 via
When the coil 24a is turned on (energized), it is communicated with the drain boat 24c. This duty cycle node 24 is operated by a computer (not shown) to turn the coil 24a ON and OFF'F' at a constant period, and also to turn the coil 24a ON and OFF at a certain period.
The time ratio (duty ratio) is controlled to generate a control pressure in the circuit 81 according to the duty ratio. The duty ratio is made smaller as the engine load (for example, engine throttle opening) increases except when the reverse is selected, and thereby the above-mentioned control pressure is made higher as the engine load increases. Further, the duty ratio at the time of reverse selection is set to 100%, and the above-mentioned control pressure is set to 0. The pressure modifier valve 22 includes a spool 22b that is biased downward in the figure by a spring 22a and control pressure from the circuit 81, and the pressure modifier valve 22 further includes an output boat 22c connected to the circuit 76, and a pilot pressure An input boat 22d and a drain boat 22e are provided to which the circuit 79 is connected, and the circuit 76 is connected to the chamber 22f facing the end face of the spool 22b far from the spring 22a. Then, the boat 22 is located at the left half position of the spool 22b in the figure.
The boats 22d and 22e are arranged so that the boat 22c is isolated from the boats 22d and 22e. The pressure modifier valve 22 receives the spring force of the spring 22a and the force of the control pressure from the circuit 81 downward in the figure on the spool 22b, and applies the force due to the output pressure from the boat 22c that has reached the chamber 22f to the spool 22b. Spool 2 is placed in a position where these forces are balanced.
2b is stroked. If the output pressure from the boat 22C is insufficient to compensate for the above-mentioned downward force, the spool 22b descends beyond the pressure regulating position shown in the left half. At this time, the boat 22c communicates with the boat 22d and receives pilot pressure from the circuit 79 to increase its output pressure. Conversely, if this output pressure is too high to match the downward force, the spool 22b will rise toward the right half position in the figure. At this time, the boat 22c communicates with the drain boat 22e, and the output pressure is reduced. By repeating this action, the pressure modifier valve 22 regulates the output pressure from the boat 22c to a value corresponding to the phase of the force due to the spring force of the spring 22a and the control pressure from the circuit 81, and uses this as a modifier pressure in the circuit. 76 to the plug 20c of the pressure regulator valve 20. By the way, as mentioned above, the control pressure increases as the engine load increases except when the reverse is selected, and since it is O when the reverse is selected, the modifier pressure is a value obtained by amplifying this control pressure by the spring force of the spring 22a. It increases as the engine load increases except when reverse is selected, and becomes 0 when reverse is selected, and the pressure regulator valve 2
0 to enable the line pressure control described above. The torque converter regulator valve 28 includes a spool 28b elastically supported in the right half position in the figure by a spring 28a,
While the spool strokes between the right half position and the left half position in the figure, the boat 28c is passed through the boat 28d, and as the spool 28b rises from the left half position in the figure, the boat 28c is moved against the boat 28d. , to reduce the continuity,
It is assumed that the degree of communication with respect to the boat 28e is increased. Spring 2 is used to control the stroke of spool 28b.
The chamber 28r facing the spool end face far from 8a is the spool 2.
A communication hole 28g provided in 8b communicates with the boat 28C. The boat 28c is connected to a predetermined lubricating part via a relief valve 82, and is connected to the lock-up control valve 30 via a circuit 83.The boat 28d is connected to the boat 20h of the pressure regulator valve 20 via a circuit 84. 28e is connected to lockup control valve 30 by circuit 85. The circuit 85 has an orifice 86 in the middle, and the orifice and the port 28
c is connected to the circuit 83 via the orifice 87, and the circuit 88 connects the oil cooler 89 and a predetermined lubricating section 9.
Pass it to 0. The torque converter regulator valve 28 is normally in the right half state in the figure, and when oil is supplied from the boat 20h of the pressure regulator valve 20 via the circuit 84, this oil is transferred from the circuit 83 to the torque converter as described later. Head to 3. When the supply pressure to the torque converter is generated, this torque converter supply pressure reaches the chamber 28f through the communication hole 284 (through the communication hole 284), causing the spool 28b to rise in the figure against the spring 28a. When the spool 28b rises from the left half position in the figure, the boat 28e opens and some of the torque converter supply pressure is removed through the boat 28e and the circuit 88, so that the torque converter supply pressure is controlled by the spring force of the spring 28a. The pressure is regulated to a determined value.The oil removed from the circuit 88 is cooled by an oil cooler 89, and then goes to the lubrication section 90.The torque converter supply pressure is also adjusted to the above value by the pressure regulating action of the torque converter regulator valve 28. If the value exceeds the value, the relief valve 82 opens and releases the excess pressure to the corresponding lubricating part to prevent deformation of the torque converter 3.The lock-up control valve 30 is constructed by coaxially abutting a spool 30a and a plug 30b. Spool 30a
When the spool 30a is at the limit position shown in the right half of the figure, the circuit 83 is connected to the circuit 91 from the torque converter release chamber 3R, and when the spool 30a is lowered to the left half position in the figure, the circuit 83 is connected to the circuit 8.
5, and when the spool 30a further descends, the circuit 9
1 is connected to the drain boat 30c. In order to control the stroke of the spool 30a, the end face of the spool 30a far from the plug 30a faces the chamber 30d, and the pressure of the circuit 91 is guided through the orifice 92 to the chamber 30e facing the end face of the plug 30b far from the spool 30a. Make it. In addition, torque converter apply chamber 3A
A circuit 93 from the circuit 93 connects to the circuit 85 at a point closer to the lockup control valve 30 than the orifice 86. In addition, the pilot pressure from the circuit 79 is applied to the plug 30b through the orifice 94 to continue applying downward force in the figure, thereby causing the spool 30a to
to prevent pulsation. The lock-up control valve 30 controls the stroke of the spool 30a by the pressure supplied to the chamber 30d, and as long as this pressure is sufficiently high, the spool 30a maintains the right half position in the figure. At this time, the oil from the circuit 83 flows through the circuit 91, the release chamber 3R, the apply chamber 3A, the circuit 93, and the circuit 85 under pressure regulation by the torque converter regulator valve 28.
It is excluded from circuit 88. Thus, the torque converter 3 transmits power in the converter state. As the pressure within chamber 30d decreases, spool 30a passes through orifice 92.
．． The pressure from the circuit 83 is lowered in the figure through the plug 30b by the pressure from the circuit 83, and when it has further descended from the left half position in the figure, the pressure regulating oil from the circuit 83 is transferred to the circuit 85.93 and the apply chamber 3.
A, the power flows to the release chamber 3R, the circuit 91, and the drain boat 30c, and the torque converter 3 transmits power under a slip control state in which the slip decreases as the pressure in the chamber 30d decreases. When the pressure in the chamber 3Od is further lowered from this state, the circuit 91 is completely communicated with the drain boat 30C due to further lowering of the spool 30a, and the pressure in the release chamber 3R is brought to 0, and the torque converter 3
transmits power in the lock-up state. The clutch valve 32 controls the stroke of the lock-up control valve 30 together with a forward clutch control valve 46 (described later), and includes a spool 32b elastically supported in the lower half position in the figure by a spring 32a. Switch to the upper half position in the figure as appropriate depending on the pressure. When the spool 32b is in the lower half position in the figure, the shuttle valve 32 connects the circuit 95 of the wheel 30d to the pilot pressure circuit 7.
9, and a circuit 96 extending from the chamber 46a of the forward clutch control valve 46 is connected to a circuit 97 from the duty solenoid 34.
When 2b is in the upper half position in the figure, the circuit 95 is connected to the circuit 97, and the circuit 96 is connected to the circuit 79. The duty solenoid 34 includes a coil 34a and a spring 34.
A circuit 97 consisting of a plunger 34b elastically supported in the closed position at d and connected to a pilot pressure circuit 79 via an orifice 98 is connected to the drain boat 34c when the coil 34a is turned on (energized). The duty solenoid 34 is connected to the coil 34 by a computer (not shown).
A is controlled to turn on and off at a constant cycle, and the ratio of ON time to the constant cycle (duty ratio) is controlled to generate a control pressure in the circuit 97 according to the duty ratio. When the shuttle valve 32 is in the upper half state in the figure and the control pressure of the circuit 97 is used to control the stroke of the lock-up control valve 30, the duty ratio of the solenoid 34 is determined as follows. In other words, under high load and low rotation speeds of the engine where the torque increasing function and torque fluctuation absorbing function of the torque converter 3 are absolutely necessary, the duty ratio is set to 0%.
As a result, the control pressure of the circuit 97 is changed to the circuit 7 which is the source pressure.
Make it the same as the pilot pressure in step 9. At this time, the control pressure in the chamber is 30
d, hold the spool 30a in the right half position in the figure,
The torque converter 3 is maintained in a converter state to meet the above requirements. As the demand for both of the above functions of the torque converter 3 becomes lower, the duty ratio is increased and the control pressure is lowered, thereby causing the torque converter 3 to function in a slip control state that matches the demand via the lock-up control valve 30. When the engine is under low load and high engine speed, where both of the above functions of the torque converter 3 are unnecessary, the duty ratio is set to 100%, thereby setting the control pressure to 0 and requesting the torque converter 3 via the lock-up control valve 30. Keep the streets locked up. Note that when the shuttle valve 32 is in the lower half state in the figure and the control pressure of the circuit 97 is used to control the stroke of the forward clutch control valve 46, the duty ratio of the solenoid 34 is set to <N-+D to reduce the select shock as described later. or to prevent creep. The manual valve 36 can be set in the parking (P) range, reverse (R) range, neutral (N) range, or
Forward automatic gear shift (D) range, forward 2nd gear engine brake (II) range, forward 1st gear engine brake (1)
A spool 36a that is stroked in a range is provided, and a line circuit 78 is connected to boats 36D, 36II, 361, and 36R according to the selected range of the spool as shown in the following table. Note that in this table, ○ marks indicate boats that communicate with the line pressure circuit 78, and no marks indicate boats that are drained. The first shift valve 38 includes a spool 38b elastically supported in the left half position in the figure by a spring 38a.
It is assumed that when pressure is supplied to 8c, it is switched to the right half position in the figure. The first shift valve 38 changes the boat 38d to the drain boat 38e when the spool 38b is in the left half position.
The boat 38f is connected to the boat 38g, the boat 38h is connected to the boat Hi, and when the spool 38b is in the right half position in the figure, the port 38d is connected to the boat 38j, and the boat 38 is connected to the boat 38k1.:, the boat 38h is connected to the boat 38. (!l:
Each person shall be allowed to pass. The second soft valve 40 includes a spool 40b elastically supported by a spring 40a at the left-hand position in the figure, and this spool is connected to the chamber 4.
When pressure is supplied to 0c, it is assumed to be in the right half position in the figure. The second shift valve 40 allows the port 40d to communicate with the drain boat 40e, the boat 40f with the boat 40g, and the boat 40h with the orifice-equipped drain boat 40i when the spool 40b is in the left half position in the figure.
] is at the right-hand position in the figure, boat 4t) d becomes boat 40j
, connect the boat 40f to the drain port 40e, and connect the boat 40f to the drain port 40e.
Let h be connected to the boat 40k, respectively. The spool positions of the first and second shift valves 38,40 are the first shift solenoid 42 and the second shift solenoid 4, respectively.
These shift solenoids are controlled by coils 42a, 44a and plungers 42b, respectively.
44b, and springs 42d and 44d. 1st
Shift solenoid 42 is connected to pilot pressure circuit 79 via orifice 99, and circuit 10 leading to chamber 38c.
0, when the coil 42a is ON (energized), the drain boat 42
c, and the control pressure in the circuit 100 is set to the same value as the pilot pressure, which is the source pressure, thereby switching the first shift valve 38 to the right half state in the figure. Further, the second shift solenoid 44 is connected to the pilot pressure circuit 79 via an orifice lot, and the circuit 102 leading to the chamber 40c is
When the coil 44a is turned on (energized), it is cut off from the drain boat 44c to make the control pressure in the circuit 102 the same value as the pilot pressure of the source pressure, thereby switching the second shift valve 40 to the right half state in the figure. do. The first to fourth forward speeds can be obtained by combinations of the ON/OFF states of these shift solenoids 42, 44, and therefore the states of the shift valves 38, 40, which are summarized in the following table. In Table 3, the mark Q in this table indicates the right half of the shift valve in the diagram (ascending), and the mark X indicates the left half of the soft delivery in the diagram (descending). ON. OF'F is determined by the vehicle speed sensor 20 based on a shift pattern predetermined by a computer 200 as a control means shown in FIG.
1 and the throttle opening sensor 202 as the vehicle running conditions and the engine load, a suitable gear position is determined, and a suitable gear position is determined to correspond to this gear position. Forward clutch computer valve 46 is connected to spool 46
11, a pilot pressure from a circuit 79 guided through an orifice 103 acts downward in the figure on this spool to prevent pulsation of the spool, and this spool is further provided with a circuit through an orifice 104.

Feedback the operating pressure of the forward clutch F/C in 05,
Act downward in the figure. The spool 46b is stroked to a position where the downward force in the figure due to these pressures and the force due to the pressure inside the chamber 46a are balanced. Spool 4
61] connects the circuit 105 at the right half position in the figure to the drain boat 46C, and connects the circuit 105 to the circuit 1 at the pressure half position in the figure.
06, the circuit 105 is provided with a one-way orifice 107 that exerts a throttling effect only on the pressure toward the forward clutch F/C, and the circuit 106 is connected to the boat 36D of the manual valve 36. 3-2 The timing valve 48 includes a spool 4gb elastically supported at the left half position in the figure by a spring 48a, and at this spool position, the boat 48c and the boat 4 with an orifice 48f are opened.
8a, the pressure inside the chamber 48e is high, and the spool 4
When 8b is in the right half position in the figure, ports 48c and 48a
The gap shall be cut off. 4-2 The relay valve 50 includes a spool 50b elastically supported at the left half position in the figure by a spring 50a, and at this spool position, the boat 50c is connected to the drain port 50d with an orifice, and pressure is supplied into the chamber 50e. When the spool 50b is at the right half position in the figure, the boat 50c is connected to the boat 50f. 4-2 The sequence valve 52 includes a spool 52b that is elastically supported at the right half position in the figure by a spring 52a, and at this spool position, the boat 52c is connected to the drain boat 52 with an orifice.
d, and when the pressure in the chamber 52e is high and the spool 52b is at the left half position in the figure, the boat 52c is connected to the boat 52f. The Lenz pressure reducing valve 54 has a spool 54b which is biased by a spring 54a in the right half of the figure (towards the device), and boats 54c and 54d that communicate with each other are provided at this spool position, and the spool 54b is on the left side in the figure. A drain boat 54e is provided which begins to communicate with the port 54c when the boat 54d is finished closing after being raised to the half position.The chamber 54f facing the end face of the spool 541+ far from the spring 54a is connected to the boat 54c via the orifice +08. (The range pressure reducing valve 54 is permanently deaf and is in the right half state in the figure, where the boat 54
When pressure is supplied to d, pressure is output from the boat 54c. This output pressure is applied to the spool 5 through the orifice 108.
4b in the figure, and as the output pressure increases, the spool 54b is raised in the figure. When the spool 54b rises above the left half position in the figure, the boat 54c communicates with the drain port 54e, reducing the output pressure from the boat 54c. When the spool 54b is lowered by more than the left half position in the figure due to this decrease in output pressure, the boat 54c communicates with the boat 54d, increasing the output pressure from the boat 54c. By repeating this action, the output pressure from the boat 54C is increased by the spring 54.
The pressure is reduced to a constant value determined by the spring force of a. The spool valve 56 includes a spool 56b elastically supported in the left half position in the figure by a spring 56a, and this spool is connected to the chamber 56.
It is held in this position when there is a pressure supply to g, but chamber 5
While no pressure is supplied to 6g, when the upward force in the figure due to the pressure from the boat 56c exceeds the value, it is stroked to the right half position in the figure. At the left half position in the figure, the boat 56d is connected to the circuit 109 from the third shift solenoid 60, and the boat 56e is connected to the drain port 56f, and at the right half position in the figure, the boat 56d is connected to the pilot pressure circuit 79. 56e is connected to the circuit 109. The third shift solenoid 60 includes a coil 60a, a plunger 60b, and a spring 60d.
circuit 109 connected to pilot pressure circuit 79 via 0
When the coil 60a is ON (energized), the drain port 60c
It is assumed that the control pressure in the circuit 109 becomes the same value as the pilot pressure which is the source pressure. Note that the third shift solenoid 60 is turned on and off by the computer 20.
0 indicates vehicle running conditions, such as vehicle speed. Determined based on engine load. Overrun clutch computer valve 58 is spring 58a
It is assumed that a spool 58b is elastically supported in the left half position in the figure, and this spool is switched to the right half position in the figure when pressure is supplied to the chamber 58c. Also, the spool 58b connects the boat 58d to the drain port 58e and the boat 58f to the boat 58g at the left half position in the figure, and connects the boat 58d to the boat 58h and the boat 58f to the drain port 58e at the right half position in the figure. It is assumed that the The overrun clutch pressure reducing valve 62 includes a spool 62b elastically supported in the left half position in the figure by a spring 62a, and when there is pressure from a boat 62c on this spool, this applies a downward force in the figure. Hold the spool 62b in this position. When pressure is supplied to boat 62d while there is no pressure inflow from boat 62c, this pressure increases the output pressure from boat 62e. This output pressure is in the chamber 62f
When it reaches a value corresponding to the spring force of the spring 62a, the spool 62b is moved to the right half position in the figure to cut off the connection between the boats 62d and 62a, and the overrun clutch pressure reducing valve 62 transfers the output pressure from the boat 62e to the spring force. 62a
Assume that the pressure is reduced to a constant value determined by the spring force. The 2-speed servo apply pressure accumulator 64 is configured by elastically supporting a stepped piston 64a at the left half position in the figure by a spring 64b, and a chamber 6 defined between both ends of the stepped piston 64a.
4c is opened to the atmosphere, and the small diameter end face and large diameter end face of the stepped piston are made to face the closed chambers 64d and 64e, respectively. The 3-speed servo release pressure accumulator 66 includes a stepped piston 66a elastically supported in the left half position in the figure by a spring 66b, and a chamber 66c defined between both ends of the stepped piston is connected to the line pressure circuit 78. The small diameter end face and the large diameter end face of the service piston are respectively connected to a sealed chamber 66d. 66e. 4th speed servo apply pressure apply pressure 68 is applied to stepped piston 6
8a is elastically supported in the left half position in the figure by a spring 68b, and a sealed chamber 68c is defined between both ends of the stepped piston, and a small diameter end face and a large diameter end face of the stepped piston are respectively sealed into the sealed chamber. 68d and 68e. The accumulator control valve 70 includes a spool 70b elastically supported in the left half position in the figure by a spring 70a, and a chamber 70c facing the end face of the spool 70b far from the spring 70a.
The control pressure of the circuit 81 is guided to. The spool 70b connects the output port door 0d to the drain boat 70e at the left half position in the figure, and when the control pressure to the chamber 70c becomes high and the spool 70b rises above the right half position in the figure, the boat 70d is connected to the line pressure circuit. 78 shall be switched and connected. Then, the output port door 0d is connected to the accumulator chamber 64d by the circuit 111.
, a chamber 7 connected to 68c and housing a spring 70a.
Also connect to 0f. Thus, the accumulator control valve 70 raises the spool 70b above the right half position in the figure by the control pressure applied to the chamber 70c except when the reverse movement is selected. As a result, the line pressure from the circuit 78 is output to the circuit 111, and when the pressure in the circuit 111 reaches a value corresponding to the control pressure, the spool 70b is elastically supported at the right half position in the figure. Therefore, the pressure in the circuit 111 is regulated to a value corresponding to the control pressure, but
Since the control pressure increases as the engine load (engine output torque) increases except when reverse is selected as described above, circuit 1
11 to chambers 64d, 68 of accumulators 64.68
The pressure supplied to c as accumulator back pressure also increases as the engine output torque increases. Note that when the reverse is selected, the control pressure is O, so no pressure is output to the circuit 111. Next, to provide a supplementary explanation of the hydraulic circuit network, the circuit 106 extending from the boat 36D of the manual valve 36 is connected halfway to the boat 38g of the first soft valve 38 and the boat 40g of the second shift valve 4o. It is also connected to the boat 56c of the shuttle valve 56 and the boat 58g of the overrun clutch control valve 58 via a more branched circuit 112. The boat 38f of the first shift valve 38 is the circuit 11
3 to the boat 50r of the 4-2 relay valve 5o, and also to the accumulator chamber 64e and the 2-speed servo apply chamber 2S/A via the one-way orifice 114, and the boat 50f is connected to the boat 50r by the circuit 115.
It is also connected to the chamber 32c. Furthermore, the boat 38h of the first shift valve 38
7) It is connected to the chamber 50e and the boat 58h of the overrun clutch control valve 58, and the boat 50c of the 4-2 relay valve 50 is connected to the boat 40k of the second shift valve 40 by a circuit 117. A pair of one-way orifices 119 are connected to the boat 38 of the first noft valve 38, together with the boat 40f of the second shift valve 40, to the high clutch 11/C by a circuit 118, and a pair of one-way orifices 119 are arranged in opposite directions. A circuit 121 branched from the circuit 118 between these orifices and the high clutch H/C is connected to the 3-speed servo release chamber 3S/R and the accumulator chamber 66e via the one-way orifice 122.
3-2 by connecting the boats 48c and 48d to the circuit 123 that bypasses the one-way orifice 122.
A timing valve 48 is inserted into this circuit 123. Therefore, when the spool 48b of the 3-2 timing valve 48 is set to the right half position in the figure and the boats 48c and 48d are cut off, only the one-way orifice 122 exists in the circuit 121, and the spool 48b is set at the left half position in the figure, and boats 48c and 48d
When the one-way orifice 12 is in communication, the one-way orifice 12
2 and orifice 48f coexist. For this reason, the 3rd speed servo release chamber 3S/ of the band brake B/B
When releasing pressure is discharged from R, one-way orifice 1
In the case of only 22, the orifice resistance becomes large, and
The one-way orifice 122 and orifice 48f
If these coexist, the orifice resistance becomes smaller. Therefore, in the hydraulic pressure control device of this embodiment, the 3-2 timing valve 48 and the third shift solenoid 60, which is controlled by the computer 200 and controls the control pressure supplied to the chamber 48e of the 3-2 timing valve 48, A variable orifice mechanism is configured. A circuit 124 branched from the circuit 121 between the one-way orifice 122 and the 3-speed servo release chamber 3S/R is connected to the chamber 52e of the 4-2 sequence valve 52, 52f to the boat 38i of the first lift valve 38 and the boat 40 of the second shift valve 40, respectively.
Connect to h. The boat 38j of the first shift valve 38 is connected to the boat 40d of the second shift valve 4G by the circuit 125, and the boat 38d is connected to the boat 40d of the second shift valve 4G.
The circuit 126 connects one person to the shuttle pole 127 [
-1 Connect to boat. The other inlet boat of the shuttle pole 127 is connected by a circuit 128 to the boat 36R of the manual valve 36 along with the circuit 77 on the one hand, and to the reverse clutch R/C and the accumulator chamber 68d via a one-way orifice 129 on the other hand, and the shuttle ball The exit boat 127 goes up to circuit 130 and connects to the low reverse brake LR/B. The boat 40j of the second shift valve 40 is connected to the boat 54c and chamber 54f of the L range pressure reducing valve 54 through a circuit 131, and
The boat 54d of the manual valve 36 is connected to the boat 36I of the manual valve 36 by a circuit 132. The boat 56e of the steering valve 56 is connected to the 3-
2 connected to the chamber 48e of the timing valve 48, and the boat 56d
is connected to chamber 58c of overrun clutch control valve 58 by circuit 134. The boat 58d of the overrun clutch control valve 58 is connected to the accumulator chamber 66d by a circuit 135, and is connected to the accumulator chambers 68e and 4 through a one-way orifice 136.
Connect to the speed servo apply chamber 43/A. Boat 58 of overrun clutch control valve 58 is connected to boat 62d of overrun clutch pressure reducing valve 62 through circuit 1.37, and boat 62e of pressure reducing valve 62 is connected to overrun clutch OR/C through circuit 138. , a check valve 139 is provided between the circuits 137 and 138. The boat 62c of the overrun clutch pressure reducing valve 62 is connected to the boat 36Ii of the manual valve 36 and the chamber 56g of the manual valve 56 through a circuit 140. The above configuration improves the operation of the hydraulic pressure control device of this embodiment as follows. Pretsunoya regulator valve 20. Due to the above-mentioned action, the pre-switching modifier valve 22 and the duty solenoid 24 regulate the oil from the oil pump O/P to a line pressure that increases in proportion to the engine output torque, except when reverse is selected, and when the reverse is selected, the oil pump The oil from 0/P is kept at a constant value, and this is output to the circuit 78. This line pressure is controlled by the pilot valve 26° and the manual valve 36. The accumulator control valve 70 and the accumulator 66 are reached, and the accumulator 66 is placed in the right half state in the figure. The accumulator control valve 70 applies the accumulator back pressure proportional to the engine output torque to the accumulator 64.6 through the circuit 111 by the above operation except when the reverse is selected.
8 chambers 64d and 68c, and these accumulators are placed in the right half state in the figure. Incidentally, when the backward movement is selected, the accumulator control valve 70 sets the accumulator back pressure to O as described above, and places the accumulators 64 and 68 in the left half state in the figure. Further, the pilot valve 26 always outputs a constant pilot pressure to the circuit 79 due to the above operation. Then, the driver does not wish to drive and turns the manual valve 36 to P.
Or if the N range is set, manual valve boat 36
D, 361, 361 skin 36H all serve as drain ports as shown in Table 2 above, and line pressure is not output from these boats, so the forward clutch is operated using the line pressure from these boats as source pressure. F/C
, high clutch H/C, band brake B/B, reverse clutch R/C, low reverse brake LR/B, and overrun clutch OR/C are all kept inactive, and the power transmission train shown in Figure 2 is used to transmit power. You can leave it in an impossible neutral state. Next, when traveling in the D range, the manual valve 36 outputs the line pressure of the circuit 78 from the boat 36D, as shown in Table 2 above. While driving in this D range, the first. The second shift solenoids 42 and 44 are turned ON and OFF as shown in Table 3 above according to the driving conditions according to the drive signal from the computer 200, and the second shift solenoids 42 and 44 are turned on and off as shown in Table 3 above.
Switch the second shift valves 38 and 40 as shown in the table. Then, each friction element B/B, H/C, F/C, OR/
C, LR/B, and R/C are activated and deactivated as shown in Table 1 above, and each gear stage (1st gear, 2nd gear, 3rd gear,
4th speed) as appropriate. For example, when speed 1 is selected, the forward clutch F/C is the only one engaged among the friction elements, and when 2nd speed is selected, the band brake B/B is engaged together with the forward clutch F/C. That will happen. by the way,
This band brake B/B engagement is performed by introducing engagement pressure into the second speed servo apply chamber 2S/A via the circuit 113. When this fastening pressure is introduced, the fastening pressure is once throttled by the one-way orifice 114, and then the pressure is adjusted by the two-speed servo apply pressure accumulator 64, and the pressure is supplied to the servo apply chamber 2S/A. Therefore, when the second gear is selected, the band brakes B/B are slowly engaged, and the shift shock is significantly reduced. Next, in the third selection, the high clutch 11/C is engaged together with the forward clutch F/C, and the band brake B/B is disengaged. The circuit 118 releases this band brake B/B.
This is done by supplying release pressure to the third speed servo release chamber 3S/R via a circuit 121 branched from the servo release chamber 3S/R. By the way, when shifting from 2nd gear to 3rd gear,
The clutch pressure and release pressure to the high clutch II/C and 3rd speed servo release chamber 3S/R are throttled by the one-way orifice 119, and the accumulator 6
Together with the operation of 6, the shift shock can be reduced. At this time, since the release pressure that passes through the circuit 121 passes through the one-way orifice 122, no orifice resistance occurs in the variable orifice mechanism. Next, when selecting 4th speed, forward clutch F/C. High clutch! (The band brake B/B is further engaged from the engaged state of /C. In other words, this engagement of the band brake B/B at the 4th speed is performed by applying the 4th speed servo of the band servo 10 via the circuit 135. This is done by supplying the 4th gear selection pressure to the chamber 4S/A. By appropriately selecting and switching each friction element engaged at each gear stage, not only upshifts but also downshifts can be performed as desired. By the way, when downshifting like this, especially when there is a soft downshift from 3rd gear to 2nd gear, the high clutch H/C
By discharging the clutch pressure of the 3rd speed servo release chamber 3S/H and the release pressure of the 3rd speed servo release chamber 3S/H, the high clutch It/
When C is released, band brake B/B is engaged. On the other hand, when downshifting from 3rd speed to 2nd speed, as is clear from Table 3 above, the first shift solenoid 42 remains OFF, while the second shift solenoid 44 changes from OFF to ON. This is done by switching. That is, when the second lift solenoid 44 is turned on, the spool 40b of the second lift valve 40 is set to the right half position in the figure, and the circuit 118 is communicated with the drain boat 40e so that the clutch pressure and the release pressure are transferred to the drain boat 40e. It is discharged from the boat 40e. By the way, when the release pressure is discharged from the third-speed servo release chamber 3S/R through the circuit 121, it passes through a variable orifice mechanism using the 3-2 timing valve 48. The 3-2 timing valve 48 is configured to be switched according to vehicle running conditions (vehicle speed, engine load). That is, when the output torque detected from the engine load is below a certain level, a correspondingly low D range pressure (line pressure) acts on the boat 56c, causing the shuttle valve 56 to be in the left half state in the figure, and 3-2. The chamber 48e of the timing valve 48 is connected to the circuit 13
3 and the boat 56e to the drain boat 56f, the 3-2 timing valve 48 is in the left half state in the figure. Therefore, at this low engine output torque, the pressure horn of the third speed servo release chamber 3S/R is discharged not only through the one-way orifice 122 but also through the orifice 48f, and the discharge speed is high. When the engine output torque is above a certain level, correspondingly, the D range pressure (line pressure) from the high port 56c puts the shuttle valve 56 in the right half state in the figure, and the 3-2 timing valve 48 moves from the circuit 109 to the circuit 133.
The state is changed by the control pressure introduced into the This control pressure is controlled by turning on and off the third shift solenoid 60, and by turning on the third noft solenoid 60, the control pressure is made the same as the pilot pressure in the circuit 79, and the third shift solenoid 60 is turned on. By turning off, the control pressure downstream of the orifice 1 is drained and becomes zero. The third shift solenoid 60 is controlled by the computer 200 as described above,
When the control pressure becomes the same pressure as the pilot pressure by turning on the solenoid 60, the 3-2 timing valve 48 moves to the right half position in the figure to shut off the orifice 48f, and when the control pressure is drained by the solenoid 600P, The -2 timing valve 48 is at the left half position in the figure, allowing the orifice and the holder 41B to communicate with each other. FIGS. 4(A) and 4(B) are flowcharts for executing the program of the computer 200 used in the hydraulic pressure control device of this embodiment. First, the main routine in FIG. 4(A) will be explained. In this main routine, first step 10
00, it is determined whether or not the gear is currently being shifted. If the gear is not being shifted (No), the vehicle speed and the throttle opening as the engine load are read in step 1100. Then, the process proceeds to step 1200, where a gear position (Gp→Gp+1) higher than the current gear position (Gp) is mapped to the data, and based on this mapped value, the next step 1300 determines whether the upshift is appropriate. judge whether If the result is valid (Y E S ), the next gear position is upshifted (Gp
+1). Next, if it is determined in step 1300 that the upshift is not appropriate (No), step 1400 is performed to shift to a gear position 1t (Gp - Gp) lower than the current gear position.
1) is mapped to data, and based on the mapped value, it is determined in step 1500 whether downshifting is appropriate. If the result is valid (Y E
S) sets the next gear position to downshift (Gp-1) in step 1510. Then, step 1
The next gear position set at 310 and 1510 respectively proceeds to step 1600, where a shift timer is set and a shift flag is set. Note that step 100
If it is determined that the gear is being shifted at 0 (YES),
The process is completed by skipping the following steps described above. Next, in the scheduled interrupt subroutine of FIG. 4(B),
First, in step 2000, a shift timer is turned on. At this time, the number of flows of the subroutine is counted, for example, every 1 m5ec, and the number of flows is added. Next, in step 2100, it is determined whether or not the gear is being shifted. If the gear is being shifted (YES), the current gear position (Gp) and the step 131 of the main flow are determined in step 2200.
0 or the next gear position (N
EXT Gp) is used to determine the type of shift, and the 0N-OF'F timer table for each type of shift is created in step 2300.
and compare. This ON-OFF timer table is shown in FIG. 5, for example, when downshifting from 3rd speed to 2nd speed. In addition, in the figure, No. 1. Second noft solenoid 42, 44
and ON-OFF operation of the third shift solenoid 60. After comparing the 0N-OFF timer tables in this way, it is determined in step 2400 whether or not the solenoid timer is ON, and if it is ON (
If YES), the process proceeds to step 241o, where the third shift solenoid 60 is turned on, while the solenoid timer is turned off.
If it is F (NO), the process proceeds to step 2420 and the third shift solenoid 6o is turned off. Steps 2410 and 2420 then proceed to step 2500 to determine whether or not the shift timer has ended. If it has ended (YES), the process returns; and if the shift timer continues (No), the process returns. Proceed to step 2600 and select the first gear position according to the next gear position (NEXT Gp). The second noft solenoid 42, 44 is driven to clear the shift flag, and then the process returns. On the other hand, the step 21
If it is determined that the gear is not being shifted at 00 (No), the gear position Gp is set to the next gear position device (NEX) at step 2700.
T Gp). Therefore, in this embodiment, due to this flow, as shown in FIG. 5, when downshifting from 3rd gear to 2nd gear, the third shift solenoid 60 is turned on before and after the second shift solenoid 44 is switched from OFF to ON. It can be switched by That is, by switching the second shift solenoid 44 from OFF to ON, the second noft valve 40 shifts to the first position.
The release pressure of the third speed servo release chamber 3S/H and the clutch pressure of the high clutch H/C are drained from the left half position to the right half position in the figure, but at this time, the third shift solenoid 60 is turned OFF. By turning on the 3-2 timing valve 48, the 3-2 timing valve 48 is switched from the left half position to the right half position in the figure, and the removal speed of the release pressure can be changed. For example, FIG. 6 shows the change characteristics of the release pressure, and in the period 1+ (determined by the number of flows counted in step 2000) in which the shift timer is activated, the first period t2 is in the third period. When the shift solenoid 60 is turned OFF, the orifices 122 and 48f of the variable orifice mechanism are communicated with each other, the orifice resistance is reduced, and the amount of release hydraulic fluid passing through is increased. Then, in the next section L3, the 37th foot solenoid 60 is turned on, thereby blocking the orifice 48rh, and the orifice resistance increases, so that the amount of hydraulic fluid passing through decreases. Furthermore, in the next section [4], the third soft solenoid 60 is turned off again, so that the amount of hydraulic fluid passing increases. Therefore, the removal speed of the release pressure is obtained as an integral amount in the interval tI of the change characteristic, and the engagement speed of the band brake B/B can be adjusted. Therefore, the length between the sections 13, that is, the third
The length of time the shift solenoid 6o is turned on) is determined by vehicle driving conditions, such as vehicle speed. By changing it according to the throttle opening degree, the amount of hydraulic fluid passing can be switched in multiple stages or steplessly. Therefore, the engagement time of the band brake by eliminating the release pressure can be optimally determined depending on the vehicle driving conditions, and the shift shock when downshifting from 3rd gear to 2nd gear can be prevented or significantly reduced. become. In this example, the throttle opening signal is used to check the engine load, but the invention is not limited to this, and the fuel injection valve type can also be used to check the opening of the injector or the accelerator. The engine load signal may be obtained from pedal depression 1 or the like. Furthermore, although the hydraulic pressure control device of this embodiment discloses a case in which the present invention is applied to control the 3rd-2nd gear downshift, it is possible to apply the present invention to other gears. Not even. Furthermore, in this embodiment, the third lift solenoid 6o is turned ON,
Although shown is a system in which the amount of hydraulic fluid passing through is changed by switching the opening and closing of the 3-2 timing valve 48 by OF'F,
A stepless variable throttle valve is provided in place of the 3-2 timing valve 48 including the orifice 48f, and the third noft solenoid 60 is duty-controlled to steplessly control the control pressure in the circuit 133, so that the control pressure in the circuit 133 is controlled steplessly. The amount of hydraulic fluid passing through the throttle valve may be continuously controlled. Further, the control pressure of the variable throttle valve may be a governor pressure mechanically generated by a governor valve or the like, without using the third shift solenoid 60 controlled by the computer 200. Incidentally, in this embodiment, a case has been described in which the amount of passing hydraulic fluid is controlled in a stepless manner, but the present invention is not limited to this, and good shift timing can be obtained even if the amount is controlled in a multi-step manner. Effects of the Invention As described above, in the hydraulic pressure control device for an automatic transmission of the present invention, the amount of hydraulic fluid passing through the hydraulic fluid supply circuit can be controlled steplessly or continuously depending on the running conditions via the variable orifice mechanism. Since the control is performed in multiple stages, the engagement or release timing of the friction element, which is determined according to the amount of passage of the hydraulic fluid, can be obtained in an optimal state in accordance with the traveling conditions. Therefore, it is possible to prevent or significantly reduce the shock during gear shifting due to switching of the frictional elements, thereby significantly improving vehicle riding comfort. FIG. 2 is an overall circuit diagram showing an embodiment of the hydraulic pressure control device; FIG. 2 is a schematic diagram showing an embodiment of the power transmission train of an automatic transmission to which the hydraulic pressure control device shown in FIG. 1 is applied;
FIG. 4 is a system diagram showing an embodiment of the control means for controlling the variable orifice mechanism used in the present invention.
A). (B) is a flowchart of an embodiment for executing the program of the control means shown in FIG. 3, FIG. 5 is a timer table used in the control means of FIG. 3, and FIG. Fig. 7 is a sectional view showing an example of a band brake as a friction element;
FIG. 8 is a diagram showing the main parts of a conventional hydraulic pressure control device. 48...3-2 timing valve (variable orifice mechanism)
, 48f... Orifice, 60... Third shift solenoid, 122... One-way orifice, 200...
Computer (control means), 201... vehicle speed sensor,
202...Throttle figure 5 change figure 7 figure 8

Claims (1)

[Claims] (1) It is equipped with a friction element that is engaged or unengaged by hydraulic fluid supplied through a circuit to switch gears, and a variable orifice mechanism is provided in the circuit to control switching of this variable orifice mechanism. In the automatic transmission that changes the amount of hydraulic fluid supplied to the friction element, the control means detects when the transmission gear is changed and controls switching of the variable orifice mechanism according to vehicle running conditions. A hydraulic pressure control device for an automatic transmission, characterized by being provided with.