JPS6263248A - Liquid pressure control device for automatic speed change gear - Google Patents

Abstract

PURPOSE:To always retain control liquid pressure at a target value by correcting the drive duty ratio of a solenoid valve according to the temperature of a control working liquid, which is detected by a fluid temperature sensor. CONSTITUTION:A signal from a throttle opening sensor 205 and a signal from a voltage sensor 207 of a duty solenoid are input to a micro-computer 200. The temperature T of a control working fluid is detected. A signal from a fluid temperature sensor 208 is input to the micro-computer. Thus, a duty solenoid is duty-controlled by driving voltage output according to the operation result of each signal to always obtain a target control liquid pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, and more particularly,
The present invention relates to a hydraulic pressure control device that can obtain control hydraulic pressure by duty-controlling a solenoid valve provided in a hydraulic circuit.

Conventional technology In recent years, automatic transmissions have been designed with various functions aimed at improving performance, such as torque converter slip control performance.

Creep prevention functions, gear shift shock prevention functions, etc. have been added. When various functions are added in this way, it becomes advantageous to control the hydraulic pressure by electronic control. In this electronic control, a solenoid valve is provided in the hydraulic pressure circuit of the control device, and the solenoid valve is duty-controlled to obtain the desired control hydraulic pressure. It is known from Publication No. 59-47552.

By the way, when electronically controlled like this, the duty ratio of the solenoid valve is the engine speed.

It is calculated according to vehicle driving conditions such as throttle opening and gear position.

Problems to be Solved by the Invention However, in such conventional hydraulic pressure control devices for automatic transmissions, the duty ratio of the solenoid valve is determined according to the vehicle driving condition, but the duty ratio is determined depending on the outside temperature, etc. The influence of hydraulic fluid temperature was not taken into account. That is, oil is normally used as the working fluid, but the viscosity of this oil changes significantly with temperature changes. However, there is a problem in that the control pressure varies greatly depending on the temperature of the hydraulic fluid, making it impossible to accurately perform each of the functions originally intended.

Therefore, the present invention provides an automatic transmission that is capable of achieving more accurate duty control pressure and reliably achieving the desired performance by controlling the solenoid valves in a manner that also takes into account the temperature of the control hydraulic fluid. The purpose of the present invention is to provide a hydraulic pressure control device.

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 a solenoid valve (a) provided in the hydraulic circuit as shown in FIG. In an automatic transmission (C) in which a control hydraulic pressure is obtained by duty-controlling the solenoid valve (a) using a drive signal from a control means (b), the temperature of the control hydraulic fluid is A liquid temperature sensor (d) that detects the liquid temperature sensor (d), and a duty correction means (e) that corrects the driving duty ratio of the solenoid valve (a) according to the detected value from the liquid temperature sensor (d). It is.

Effect With the above-described configuration, the hydraulic pressure control device of the present invention adjusts the drive duty ratio of the solenoid valve (a) according to the temperature of the control hydraulic fluid detected by the fluid temperature sensor (d), that is, the viscosity of the hydraulic fluid. is corrected, so the target control fluid pressure can always be obtained regardless of changes in fluid temperature.

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

That is, FIG. 2 shows the entire circuit of a hydraulic pressure control device showing one embodiment of the present invention, and the power transmission train of an automatic transmission controlled by this hydraulic pressure control device is, for example, the schematic diagram of FIG. 3. There is something like this.

That is, this power transmission train includes a torque converter 3 that transmits rotation from the engine output shaft l 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 l, and includes a pump impeller 3P that is also used to drive the oil pump 0/P, and a turbine that is fluidly driven by the pump impeller via internal working fluid and transmits power to the input shaft 2. It consists of a stator 3s that is placed on a fixed shaft via a runner 3T and a one-way clutch 7 and increases the torque to the turbine launch 3T, and a lock-up clutch 3 is connected to the stator 3s.
This is a normal lock-up torque converter with L added. The torque converter 3 is supplied with 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 the turbine launch 3T. (in the converter state) torque is transmitted to the input shaft 2 while increasing, and conversely, working fluid is supplied from the apply chamber 3A, and while the working fluid is removed from the release chamber 3R, the lock-up clutch 3L is engaged and the engine power is increased. is transmitted as is to the input shaft 2 via this lock-up clutch (in the lock-up state). 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 launch 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 also a simple planetary gear set consisting of a sun gear 5S, a ring gear 5R, a pinion 5P, and a carrier 5C. As a group.

Next, the various friction elements mentioned above will be explained. The carrier 4C can be appropriately connected to the input shaft 2 via a high clutch H/C, and the sun gear 4S can be appropriately fixed by a band brake B/B, and the input shaft 2 can be connected by a reverse clutch R/C.
It can be combined as appropriate. Further, the carrier 4C can be appropriately fixed by a multi-plate low reverse brake LR/B, and is prevented from being reversed (rotation in the opposite direction to the engine) via a row one-way clutch LO/C. ring gear 4
R is integrally connected to the carrier 5C and drivingly connected to the output shaft 6, and connects the sun gear 5S to the human power shaft 2. Ring gear 5R
can be appropriately coupled to the carrier 4C via the overrun clutch OR/C, and is also correlated to the carrier 4C via the forward one-way clutch FO/C and the forward clutch F/C. It is assumed that the forward one-way clutch I'O/C connects the ring gear 5R to the carrier 4C in the reverse direction (direction opposite to the engine rotation) when the 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 P/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/A 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 P3 is also supplied to the servo release chamber 3s/R, the band brake B/B becomes inactive, and after that, when the 4th speed selection pressure P4 is also supplied to the 4th speed servo apply chamber 4S/A. , band brake B/B is activated.

Such a power transmission train includes friction elements B/B, H/C, F/
C.

OR/C, LR/B, R/C are operated in various combinations as shown in the table below, and friction elements FO/C, L
(Coupled with the appropriate differential of 17C, the rotational state of the elements constituting the planetary gear sets 4 and 5 can be changed, thereby changing the rotational speed of the output side 6 with respect to the rotational speed of the input shaft 2. As shown in the table, it is possible to obtain the following gears: 4 forward speeds and 1 reverse speed. In the table below, the ○ mark indicates operation (hydraulic inflow), but the 2. * mark operates when engine braking is required. Indicates the power friction element.

And, ・:】, ・Overrun clutch OR as shown
While /C is activated, the forward one-way clutch PO/C placed in parallel with it is deactivated, and the low lever =
7--It goes without saying that while the spray brake LR/B is operating, the row one-way clutch LO/C disposed in parallel therewith is inoperative.

Table 1 By the way, the hydraulic pressure side control device shown in FIG. Control valve 30, shuttle valve 32, duty solenoid 34, manual valve 3
6, 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 4
8.4-2 relay valve 50.4-2 sequence valve 52,
■ Range pressure reducing valve 54, shuttle-8 = valve 56, overrun clutch control valve 58, third shift solenoid 60. Overrun clutch pressure reducing valve 63. 2nd speed servo apply pressure accumulator 64. 3rd speed servo release pressure accumulator 66, 4th speed servo apply pressure accumulator 68, which constitutes the main part of the shock reduction device of the present invention, and accumulator control valve 70.
The main components are the torque converter 3, forward clutch F/C, and high clutch H/C.
, band brake B/B.

Reverse clutch R/C, low reverse brake LR/
B.

Overrun clutch OR/C and oil pump O/
It is configured by connecting to P as shown in the figure.

The pressure regulator valve 20 includes a spool 20b elastically supported in the left half position in the figure by a spring 20a, and a plug 20c abutting 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 2o is connected to the circuit 71 via a damping orifice 72.
The pressure inside is received by the pressure receiving surface 20d of the spool 20b, and the spool 211b is biased downward by this,
Ports 20e to 20h are provided which are opened and closed depending on the stroke position of the spool 20b. The port 20e is connected to the circuit 71, and is arranged so that as the spool 20b descends from the left half position in the figure, it communicates with the ports 20h and 2Of.

As the spool 20b descends from the left half position in the figure, the communication between the port 2Of and the drain boat port 20g is reduced, and at the point when the communication with this is cut off, the port 2Of
Arrange it so that it starts communicating with 0e. and port 2O
f is connected to the capacity control actuator 75 of the oil pump O/P via a circuit 74 in which a bleed 73 is present. The oil pump O/P is a variable capacity vane pump driven by the engine as described above, and the eccentricity is reduced when the pressure toward the actuator 75 exceeds a certain value, so that the capacity becomes smaller.

The plug 20c of the pressure regulator valve 2o receives the modifier pressure from the circuit 76 on its lower end face in the figure, and also receives the backward selection pressure from the circuit 77 on the pressure receiving surface 20i, and generates an upward force in the figure in response to these pressures. Spool 20b
shall be added to.

The pressure regulator valve 2o is normally in the left half state in the figure, and when oil is discharged from the oil pump 0/P, this oil flows into the circuit 71. Spool 2
At the left half position of 0b, no oil in the circuit 71 is 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 20a, and connects the port 20e to the port 20h. As a result, the above pressure is partially drained from the port 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 in the circuit 7I (hereinafter referred to as line pressure) to a value corresponding to the spring force of the spring 2 (la).By the way, the plug 20c has a circuit 76 The plug 20c comes into contact with the spool 20b as shown in the right half of the figure due to the upward force caused by the modifier pressure from the modifier pressure, and this upward force is applied to the spool 20b to assist the spring 20a. Ifia pressure occurs at times other than when reversing is selected as described below,
Since it increases in proportion to the engine load (engine output torque), the above-mentioned line pressure increases as the engine load increases except when reverse is selected.

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, communicates the port 20f with the port 20e, and blocks it from the drain port 20g. This will cause port 20
A portion of the oil e is removed from port 2Of and bleed 73, but a feedback pressure is generated within circuit 74.

This feedback pressure increases as the rotational speed of the oil pump O/P increases, and reduces the eccentricity (capacity) of the oil pump O/P via the actuator 75. In this way, the capacity of the oil pump O/P is controlled so that the discharge amount remains constant while the rotational speed exceeds a certain value, thereby preventing an increase in power loss of the engine due to discharge of more than necessary oil.

The line pressure generated in the circuit 71 as described above is supplied to the pilot valve 26, the manual valve 36, the accumulator control valve 70, and the 3-speed servo release pressure accumulator 66 through the line pressure circuit 78.

The pilot valve 26 includes a spool 26b elastically supported in the upper half position in the figure by a spring 26a, the end face of the spool 26b far from the spring 26a faces the chamber 26c, and the pilot valve 26 is further provided with a drain port 26d. , a pilot pressure circuit 79 with strainer S/T is maintained. A communication hole 26e is provided in the spool 26b to guide the pressure of the pilot pressure circuit 79 to the chamber 26c.
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 rises to the communication hole 26e and reaches the chamber 26c, 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 of the figure,
At the same time as the circuit 79 and the circuit 78 are cut off, it is connected to the drain boat 26d. At this time, the pressure in the circuit 79 is reduced, and when the spool 26b is pushed back by the spring 26a due to this pressure reduction, the pressure in the circuit 79 is increased again. In this way, the pilot valve 26 can reduce the line pressure in the circuit 78 to a constant value determined by the force of the spring 26a, and output it to the circuit 79 as pilot pressure.

This pilot pressure is transmitted through circuit 79 to pressure modifier valve 22, duty node 24, 34, lockup control valve 30. Forward clutch control valve 46, shuttle valve 32, first. 2nd and 3rd shift solenoid 42.44.60. Shuttle valve 56 is supplied.

The duty valve 24 as a solenoid valve consists of a coil 24a, a spring 24d and a plunger 24b, and is connected to a pilot pressure circuit 79 via an orifice 8o.
The circuit 81 connected to the drain port 24c is connected to the drain port 24c when the coil 24a is turned on (energized). The duty node 24 is controlled by a computer (not shown) to turn the coil 24a ON and OFF at a constant cycle, and to control the ratio of the ON time to the constant cycle (duty ratio), so that a circuit 81 is connected to the coil 24a according to the duty ratio. generates control pressure. 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. Also, the duty ratio when selecting reverse is 1o.
.

%, the above 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 a circuit 81, and the pressure modifier valve 22 is further connected to an output boat 22c1 pilot pressure circuit to which the circuit 76 described above is connected. A circuit 76 is connected to a chamber 22f facing the end face of the spool 22b far from the spring 22a.

Then, at the left half position of the spool 22b in the figure, it is exactly port 2.
These ports are arranged so that port 2c is isolated from ports 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 transmits the force due to the output pressure from the port 22c reaching 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 port 22c is insufficient to match the downward force, the spool 22b descends beyond the pressure regulating position shown in the left half.

At this time, the port 22c communicates with the port 22d, and receives pilot pressure from the circuit 79 to increase the 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 port 22e, and the output pressure is reduced. By repeating this action, the pressure modifier valve 22 adjusts the output pressure from the port 22c to a value corresponding to the force due to the spring force of the spring 22a and the control pressure from the circuit 81, and uses this as the modifier pressure. The circuit 76 supplies 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 0 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. increases as the engine load increases except when reverse is selected, becomes 0 when reverse is selected, and 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 in the figure and the left half position in the figure, the port 28c is communicated with the port 28d, and as the spool 28b rises from the left half position in the figure, the port 28c is connected to the port 28d. The degree of communication is decreased with respect to the port 28e, and the degree of communication is increased with respect to the port 28e. Spring 2 is used to control the stroke of spool 28b.
The chamber 28f facing the spool end face far from 8a is the spool 2.
A communication hole 28g provided in 8b communicates with the port 28c. The port 28c is connected to a predetermined lubricating part through a relief valve 82, and is connected to the lock-up control valve 30 through a circuit 83. The port 28d is connected to the port 20h of the pressure regulator valve 20 through a circuit 84, and the port 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.
Let's get through to o.

The torque converter regulator valve 28 is normally in the right half state in the figure, and when oil is supplied from the port 20h of the pre-pressure regulator valve 20 via the circuit 84, this oil is supplied from the circuit 83 to the torque converter as described below. Head to converter 3. When supply pressure to the torque converter is generated, this torque converter supply pressure reaches the chamber 28f through the communication hole 28g, 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 due to an increase in the torque converter supply pressure, the port 28e opens and a portion of the torque converter supply pressure is removed through the port 28e and the circuit 88, thereby reducing the torque converter supply pressure. The pressure is adjusted to a value determined by the spring force of the spring 28a. The oil removed from the circuit 88 is cooled by an oil cooler 89 and then directed to the lubricating section 9o. Note that if the torque converter supply pressure exceeds the above value due to the pressure regulating action of the torque converter regulator valve 28, the relief valve 82 opens and releases the excess pressure to the corresponding lubricating part to prevent deformation of the torque converter 3. do.

The lock-up control valve 30 is constructed by coaxially abutting a spool 30a and a plug 30b.
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 shall be connected to the drain port 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 911, 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, and is removed from the circuit 88. Thus torque converter 3
transmits power in the converter state. As the pressure within chamber 30d decreases, spool 30a moves toward orifice 9.
The pressure from 2.94 is lowered in the figure via the plug 30b, 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, the apply chamber 3A, the release chamber 3R, Circuit 91, drain port 30c
The torque converter 3 starts to flow to the chamber 30d.
Power is transmitted under a slip control state in which the slip decreases as the internal pressure decreases. When the pressure inside the chamber 30d is further lowered from this state, the circuit 91 is completely communicated with the drain port 30c due to the further lowering of the spool 30a, and the pressure in the release chamber 3R is reduced to 0, and the torque converter 3 is in a locked-up state to generate power. communicate.

The shuttle valve 32 controls the stroke of the lock-up control valve 30 together with a forward clutch control valve 46 (to be 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 port 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 two-hand state shown 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 speed 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.
%, thereby making the control pressure of circuit 97 the same as the pilot pressure of circuit 79, which is the source pressure. At this time, the control pressure is
At 0d, the spool 30a is held in the right half position in the figure, and the torque converter 3 is kept in the converter state to meet the above requirements. As the requirements for both of the above functions of the torque converter 3 become lower, the duty ratio is increased and the control pressure is lowered, thereby increasing the lock-up control valve 3o.
The torque converter 3 is operated in a slip control state that matches the demand through The torque converter 3 is maintained in the lock-up state as required via the lock-up control valve 3o by setting the pressure to 0.

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 reduce the N→D select shock as described later. Or,
determined to prevent creep.

The manual valve 36 can be set in the parking (P) range, reverse (R) range, neutral (N) range, or
It is equipped with a spool 36a that is stroked to the forward automatic transmission (D) range, the forward second speed engine brake (n) range, and the forward first speed engine brake (1) range, and the line circuit 78 is connected to the next line according to the selected range of the spool. It is assumed that ports 3[)D, 3611, 36I, and 36R are connected as shown in the table. Note that in this table, ○ marks indicate ports that communicate with the line pressure circuit 78, and no marks indicate ports 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 connects the port 38d to the drain boat 38e when the spool 38b is in the left half position.
Port 38f is connected to port 38g, port 38h is connected to port 38i, and when spool 38b is in the right half position in the figure, port 38d is connected to port 38j, port 38f is connected to port 38k, and port 38h is connected to port 38Q''. It shall be communicated.

The second shift valve 40 includes a spool 40b elastically supported in the left half position in the figure by a spring 40a.
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 port 40e, the port 40f to the port 40g, and the port 40h to the orifice-equipped drain port 40i when the spool 40b is in the left half position in the figure.
When is in the right half position in the figure, port 40d is connected to port 40j, port 40f is connected to drain port 40e, port 40h is connected to
are respectively connected to the port 40k.

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 the orifice 101, and connects the circuit 102 to the chamber 40c.
When the coil 44a is ON (energized), it is cut off from the drain port 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 and OFF states of these soft solenoids 42 and 44, and therefore the states of the shift valves 38 and 40, which are summarized in the table below.

Below is a blank space in Table 3. In this table, the ○ marks indicate the right half of the shift valve in the figure (up), the X marks the left half of the shift valve in the figure (down), and the shift solenoid 42. 44 ON.

OFF is determined by a computer (not shown) that determines a suitable gear position based on the vehicle speed and engine load based on a predetermined gear change pattern, and determines the appropriate gear position.

Forward clutch computer valve 46 is connected to spool 48
A pilot pressure from a circuit 79 guided through an orifice 103 is applied to this spool downward in the figure to prevent pulsation of the spool, and a circuit -27= The operating pressure of the forward clutch F/C in 105 is fed back and applied downward in the figure. The spool 46b absorbs the downward force in the figure due to these pressures and the chamber 4
Stroke to a position where the force due to the pressure inside 6a is balanced. When the spool 46b is in the right half position in the figure, the circuit 10
5 is connected to the drain boat 46C, and in the left half position in the figure, the circuit IQ5 is connected to the circuit 106, and the circuit 105 has a one-way orifice 107 that exerts a throttling effect only on the hydraulic pressure directed to the forward clutch F/C. The circuit 106 is connected to the boat 36D of the manual valve 36.

3-2 The timing valve 48 includes a spool 48b elastically supported at the left half position in the figure by a spring 48a, and at this spool position there is communication between the boat 48c and the boat 48d with the orifice 411f, and the pressure in the chamber 48e is reduced. When the boat 48c is high and the spool 48b is in the right half position in the figure, the boat 48c, 48
d 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 boat 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 range pressure reducing valve 54 includes a spool 54b which is biased toward the right half position in the figure by a spring 54a, and boats 54c and 54d are provided that communicate with each other at this spool position, and the spool 54b is located at the left half position in the figure. A drain port 54e is provided which begins to communicate with the boat 54c when the boat 54d is raised into position and the boat 54d is closed. Spool 5 far from spring 54a
The chamber 54f facing the end face of the tube 4b is connected to the boat 54C via an orifice 108. Thus, the I range pressure reducing valve 54 is normally in the right half state in the figure, and when pressure is supplied to the boat 54d, pressure is output from the boat 54c.

This output pressure acts on the lower end surface of the spool 54b in the figure through the orifice 108, and as the output pressure increases, the spool 54b
4b as shown in the figure. When the spool 54b rises above the left half position in the figure, the port 54c becomes the drain port 54e.
The output pressure from port 54c is reduced. When the spool 54b descends beyond the left half position in the figure due to this decrease in output pressure, the port 54c communicates with the port 54d, increasing the output pressure from the port 54c. By repeating this action, the output pressure from the port 54c is reduced to a constant value determined by the spring force of the spring 54a.

The shuttle 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 port 6g, when the upward force in the figure due to the pressure from port 56c exceeds the value, it is stroked to the right half position in the figure. Port 56d is connected to the circuit 109 from the third shift solenoid 60 at the left half position in the figure, port 56e is connected to the drain boat 56f, and port 56d is connected to the pilot pressure circuit 79 at the right half position in the figure. 56e is connected to the circuit 109.

The third shift solenoid 60 is composed of a coil 60a, a plunger 60b, and a spring 6od.
circuit 109 connected to pilot pressure circuit 79 via 0
When the coil 60a is ON (energized), the drain boat 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 whether the third shift solenoid 60 is turned on or off is determined by a computer (not shown).

Overrun clutch computer valve 58 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. Further, the spool 58b connects the port 58d to the drain boat 58e and the port 58f to the port 58g at the left half position in the figure, and the port 58d to the port 58h and the port 58f to the drain boat 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 at the left half position in the figure by a spring 62a, and when there is pressure from a port 82c on this spool, this applies a downward force in the figure. Hold the spool 62b in this position. When pressure is supplied to port 62d while there is no pressure inflow from port 62c, this pressure increases the output pressure from port 62e. This output pressure is in the chamber 62f
When the value corresponding to the spring force of the spring 62a is reached, the spool 62b is moved to the right half position in the figure to cut off the connection between the ports 82d and 62a, and the overrun clutch pressure reducing valve 62 transfers the output pressure from the port 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 constructed by elastically supporting a service 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 3rd speed servo release pressure accumulator 66 is a stepped screw.
A chamber 66c is defined between both ends of the stepped piston.
is connected to the line pressure circuit 78, and the small diameter end face and large diameter end face of the stepped = 32-piston are respectively placed in 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 connected to a sealed chamber 68d. , 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 port 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.
The chamber connected to 68c and housing the spring 70a? O
Also connect to f.

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. In addition, since the control pressure is 0 when the reverse movement is selected, 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 port 36D of the manual valve 36 is connected to the port 38g of the first shift valve 38 and the port 40g of the second shift valve 40, and the circuit 106 extends from the port 36D of the manual valve 36. It is also connected to port 56c of shuttle valve 56 and port 58g of overrun clutch control valve 58 via a more branched circuit 112. The port 38f of the first shift valve 38 is connected to the circuit 11
3 to the port 50f of the 4-2 relay valve 5o, and is also connected to the accumulator chamber 64e and the 2-speed servo apply chamber 2S/A via the one-way orifice 114, and the port 50f is connected to the shuttle valve 32 by the circuit 115.
It is also connected to the chamber 32c. Furthermore, the port 38h of the first shift valve 38, the circuit 116, the 4-2 relay valve 5o, the chamber 50e, and the overrun clutch control valve 58.
Port 58h +: Connected to 4-2 relay valve 50 port 50c and second shift valve 4o by circuit 117
Connect to port 40k of 3812 to the port 38 of the first shift valve 38, and the port 40f of the second shift valve 40.
and connected to the high clutch H/C by circuit 118,
A pair of one-way orifices 119 and 120 arranged in opposite directions are inserted in the middle. 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, and a circuit 123 that bypasses the one-way orifice 122 A 3-2 timing valve 48 is inserted into this circuit 123 by connecting ports 48c and 48d therein. One-way orifice = 35- A circuit 124 branched from the circuit 121 between the chair 122 and the 3rd speed servo release chamber 38/R is connected to the chamber 52e of the 4-2 sequence valve 52, and the port 52c of the 4-2 sequence valve 52 is connected. 52f are connected to the port 38i of the first shift valve 38 and the port 40h of the second shift valve 40, respectively.

The port 38j of the first shift valve 38 is connected to the port 40d of the second shift valve 40 by the circuit 125, and the port 38j is connected to the port 40d of the second shift valve 40.
is connected by circuit 126 to one inlet boat of shuttle ball 127. The other inlet port of the shuttle ball 127 is connected by a circuit 128 on the one hand to the port 36R of the manual valve 36 together with said circuit 77 and on the other hand to the reverse clutch R/
The exit boat of the shuttle ball 127 goes up to the circuit 130 and is connected to the low reverse brake LR/H. A port 40j of the second shift valve 40 is connected to a port 54c and a chamber 54f of the range pressure reducing valve 54 through a circuit 131, and a port 54d of the range pressure reducing valve 54 is connected to a port 361 of the manual valve 36 through a circuit 132.

The port 56e of the shuttle valve 56 is connected to the 3-
2, connected to the chamber 48e of the timing valve 48, and connected to the port 56d.
is connected to chamber 58c of overrun clutch control valve 58 by circuit 134. Port 58d of overrun clutch control valve 58 is connected to accumulator chamber 66d by circuit 135 and is connected to accumulator chambers 68e and 4 through one-way orifice 136.
Connect to speed servo apply chamber 4S/A. Port 58f of overrun clutch control valve 58 is connected to port 62d of overrun clutch pressure reducing valve 62 by circuit 137, port 62e of pressure reducing valve 62 is connected to overrun clutch OR/C by circuit 138,
A check valve 139 is provided between circuits 137 and 138. Port 62c of overrun clutch pressure reducing valve 62 is connected to port 38m of manual valve 36 and chamber 56g of shuttle valve 56 through circuit 140.

By the way, the duty solenoid 24 used in the hydraulic pressure control device is driven by a microcomputer 200 as a control means shown in FIG.

This microcomputer 200 has a central processing unit (
It consists of a CPU (CPU) 201, a memory 202, and an input/output interface circuit (Ilo) 203. and,
The microcomputer 200 controls the engine rotation speed (N
e) A signal from the engine speed sensor 204 that detects.

A signal from the throttle opening sensor 205 that detects the engine throttle opening (TH), a signal from the gear position sensor 206 that detects the selected gear position (G) of the automatic transmission, and the duty sensor that generates the duty control pressure. Voltage sensor 207 that detects the driving voltage (V) of the solenoid 24
Furthermore, in this embodiment, in addition to the above-mentioned signals, the temperature (T) of the control hydraulic fluid, that is, the hydraulic oil, is input.
A signal from an oil temperature sensor 208 as a liquid temperature sensor is input. The duty solenoid 24 is duty-controlled by the drive voltage that is output based on the calculation results of these signals.

For this purpose, the microcomputer 200 executes the control program shown in FIG. 5, for example. That is, in this flowchart, first, in step I, the engine speed (N
e), engine throttle opening (TH) and gear position (G) are read, and then in step ■, these three pieces of information Ne,
The target duty control pressure is calculated based on TH and G. Then, in the next step (2), the reference duty (d) for the target duty control pressure is looked up from the table data corresponding to FIG. 6. After that, in step 2 and step 2, the solenoid drive voltage (V) and oil temperature (T) are read, and in step 2, the duty correction coefficient α- is calculated from these voltage (V), oil temperature (T), and constants β and γ. Calculate β・■・T+γ. In the next step (2), a duty correction is performed by multiplying this correction coefficient (α) by the reference duty (d) to obtain a correction duty D−α・d, and this duty (D
) is output to the duty solenoid 24 in the next step (3). In this embodiment, by inputting not only the oil temperature (T) but also the drive voltage (V) as a correction signal, it is possible to improve the responsiveness of the duty solenoid 24 to voltage fluctuations.

Therefore, in the hydraulic pressure control device of this embodiment, the duty solenoid 24 is duty-controlled in consideration of the oil temperature (T), so that the circuit as shown in FIG. 78 line pressure is regulated via the pilot valve 26, and when this regulated pilot pressure is supplied to the duty solenoid 24 via the circuit 79, the control pressure downstream of the orifice 80 changes due to the oil temperature change. The pressure is controlled to the target pressure regardless of the pressure. This appropriately controlled duty control pressure is supplied as a control pressure to the upper end of the pressure modifier valve 22 in the drawing, and is also supplied to the lower end of the accumulator control valve 7.9' in the drawing. Therefore, the pressure modifier valve 22 is operated properly by the control pressure supplied to the pressure modifier valve 22, and the signal pressure output to the pressure regulator valve 20 via the circuit 76 is set as the oil temperature in consideration of the oil temperature. The pressure regulator valve 2
Operate 0. Therefore, the line pressure regulated by the pressure regulator valve 20 can also be set to an appropriate pressure depending on the oil temperature. It is possible to prevent a large shift shock from occurring due to excessive line pressure. In this embodiment, it has been described that the duty ratio of the duty solenoid 24 is corrected according to the oil temperature (T), but when the oil temperature is extremely low, for example -4
When the temperature is below 0°C, the duty ratio is set to 0%, the drain amount of the circuit 79 is set to 0, and the pressure regulator valve 20 is
The line pressure is set to the maximum value so that each friction element is securely engaged.

Incidentally, by supplying the duty control pressure from the duty solenoid 24 to the accumulator control valve 7o, the accumulator back pressure supplied to the accumulators 64 and 68 is also controlled according to the oil temperature (T), and is maintained at an appropriate level. It is possible to obtain accurate shift timing.

FIG. 7 shows another embodiment of the control program executed by the microcomputer 200, and in this embodiment, steps 1. I
The same processing as I and V is performed. And next step ■
In step 2, the table data in FIG. 8 is searched based on the oil temperature (T) read in step (2). That is, this table data includes, for example, data corresponding to T+ in the figure when the oil temperature (T) is 120°C, data for T2 when it is 80°C, data for T3 when it is 60°C, and -30°. In the case of C, the data of T4 is used. Note that when the oil temperature (T) is extremely low, for example, -40° C. or lower, a duty ratio of 0% is used as data, as shown by the data at T5 in the figure. Then, in step XIV, the output duty ratio (D) corresponding to the target duty control pressure is looked up from the retrieved table data, and this duty ratio (D) is output to the duty solenoid 24 in step xv.

In this embodiment as well, the duty solenoid 24 has an oil temperature (T
), the drive duty ratio is corrected by the above-mentioned search of the table data, so that the target duty control pressure can be generated accurately.

In each of the above-mentioned embodiments, an example has been described in which duty control taking oil temperature into consideration is performed using the duty solenoid 24. It goes without saying that the present invention can be applied to the duty solenoid 34 that supplies control pressure to the control valve 46. Furthermore, it goes without saying that the present invention is applicable not only to the type of hydraulic pressure control device shown in FIG. 2 but also to solenoid valves used in other types of hydraulic pressure control devices.

As described in detail, in the automatic transmission hydraulic pressure control device of the present invention, the drive duty ratio of the solenoid valve is corrected according to the temperature and viscosity of the control hydraulic fluid. As a result, the duty-controlled control fluid pressure can always be maintained at the target value regardless of fluid temperature changes, and each function that achieves high performance can be fully utilized through precise control. This has the excellent effect of significantly improving drivability.

[Brief explanation of drawings]

-43= Fig. 1 is a conceptual diagram showing a hydraulic pressure control device for an automatic transmission according to the present invention, Fig. 2 is an overall circuit diagram showing an embodiment of the hydraulic pressure control device according to the present invention, and Fig. 3 is a conceptual diagram showing a hydraulic pressure control device according to the present invention. 4 is a system diagram showing an embodiment of the present invention. FIG. 5 is a flowchart of a control program in the hydraulic control device of the present invention. The figure is a table data characteristic diagram of the standard duty used in the flowchart in Figure 5, Figure 7 is a flowchart showing another example of the control program used in the present invention, and Figure 8 is the output used in the flowchart in Figure 7. FIG. 9 is a table data characteristic diagram of duty, and FIG. 9 is a characteristic diagram of change in duty control pressure depending on oil temperature. 24, 34... Duty solenoid (solenoid valve), 79... Hydraulic pressure circuit, 200... Microcomputer (control means), 208... Oil temperature sensor (liquid temperature sensor), T... Oil temperature (liquid temperature). 2 other people Figure 6 EIJIE% L! II'l Misaki ff1 (kcl/Cm
') Figure 8

Claims (1)

[Claims] (1) In an automatic transmission that has a solenoid valve provided in the hydraulic pressure circuit, control hydraulic pressure can be obtained by controlling the duty of the solenoid valve using a drive signal from a control means. An automatic transmission comprising: a liquid temperature sensor for detecting the temperature of hydraulic fluid; and a duty correction means for correcting the driving duty ratio of the solenoid valve according to the detected value from the liquid temperature sensor. hydraulic control device.