JPS62159839A - Engine brake control device for automatic variable transmission - Google Patents

Abstract

PURPOSE:To guarantee the effect of an engine brake in case of any emergency in an electronic control system, by setting a low-speed state holding circuit for leading low-speed stage engine brake range pressure, from a manual valve to a certain shift valve, and holding this shift valve in a specific condition. CONSTITUTION:I-Range pressure output from a low-speed stage holding circuit 131, holds the spool 40b of the second sift valve 40 in the right half part condition. Accordingly, as this shift valve condition can be held certainly by the I-range pressure, even if an electronic control system of the second shift solenoid 44 goes wrong, engine brake at the corresponding speed change stage can be got certainly. In addition, I-range pressure output from a low-speed stage holding circuit 131, holds an over-run clutch control valve 58 in the left half part condition. Accordingly, as this condition can be held certainly by the I-range pressure, for making the over-run clutch OR/C to be operatable, even if the electronic control system of the third shift solenoid 60 goes wrong, engine brake can be secured certainly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine brake control device for an automatic transmission.

(Prior Art) An automatic transmission is configured to automatically change gears by switching a power transmission path by selectively operating various friction elements (clutches, brakes, one-way clutches, etc.). During this power transmission, the one-way clutch functions as a reaction force element for the rotating member, and through its operation, receives the reaction force from the rotating member to enable the power transmission.

Therefore, when reverse drive torque is directed to the rotating member during coasting, the one-way clutch idles and cannot transmit this reverse drive torque to the engine, so although it can eliminate shocks and rattling noises, it does not provide engine braking. make it impossible to do so.

For this reason, it is common practice to provide an engine braking friction element in parallel with the one-way clutch and operate this element as appropriate to effect engine braking.

On the other hand, automatic transmissions today tend to be electronically controlled for the purpose of increasing control precision and simplifying the control system, and the applicant of the present application has previously proposed electronically controlled automatic transmissions as described in Japanese Patent Application No. 199316-1983. Developed a transmission. In this case, in the forward automatic shift range of the manual valve, in a specific state of a shift valve that is electronically controlled, the low gear of 1st or 2nd speed is selected depending on the state of another shift valve that is also electronically controlled. However, in the other states of the above-mentioned shift valves, it is configured to select the third speed or the fourth speed medium/high speed depending on the state of the other shift valves, and also selects the low speed engine brake range of the manual valve. In this, the shift valve is electronically controlled to be in the specific state, and the engine braking friction element is operated by the low gear engine brake range pressure from the manual valve, so that engine braking in the low gear is achieved. I'm trying to get it.

(Problems to be Solved by the Invention) However, in such a configuration, an electronic control system that puts the shift valve in the specific state, which becomes oxidized, in the low speed engine brake range of the manual valve, for example, detects the low speed engine brake range of the manual valve. inhibitor switch,
If the solenoid valve that sets the solenoid shift valve to the specific state or the computer that connects them malfunctions and the solenoid shift valve cannot be brought to the specific state, the low gear is obtained, and the middle and high gears are This causes the engine to brake, resulting in engine play.

(Means for Solving the Problems) The present invention takes measures to ensure that the lower gear is raised by one level even in the event of such a failure, and in the automatic transmission of the above type, the low gear engine brake range pressure is applied from the manual valve. The present invention is characterized by a configuration in which a low gear holding circuit is provided which guides the shift valve to the oxidized shift valve and maintains it in the specific state.

(Function) The state of the above-mentioned oxidizing shift valve is determined by electronic control, and the automatic transmission selects a low gear in that specific state. When engine braking is desired and the manual valve is set to the low gear engine brake range, the above-mentioned shift valve is electronically controlled to the above specified state, and the low gear engine brake range pressure from the manual valve operates the engine brake friction element. .

Therefore, the automatic transmission can apply engine braking in low gears.

On the other hand, the low speed engine brake range pressure from the manual valve also reaches the oxidized shift valve via the low speed holding circuit and maintains it in the specified state. Therefore, even if the electronic control system of this shift valve fails and the shift valve cannot be brought into a specific state, the specific state of this shift valve will be achieved by the low gear engine brake range pressure, and the low speed will be maintained in that range. It is possible to maintain the gear position and ensure engine braking in this low gear position.

(Example) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 2 shows a power transmission train of an automatic transmission to which the engine brake control device of the present invention is applied. This power transmission train includes a torque converter 3 that transmits rotation from an engine output shaft 1 to a human power shaft 2, a first planetary gear It is composed of a set 4, a second planetary gear set 5, an output shaft 6, and various friction elements described below.

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 0/P, and a turbine that is fluidly driven by the pump impeller via internal working fluid and transmits power to the human power shaft 2. It consists of a stator 3s placed on a fixed shaft via a runner 3T and a one-way clutch 7 to increase torque to the turbine runner 3T, and a lock-up clutch 3
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 turbine runner 3T. (in the converged state) torque is transmitted to the human power shaft 2 while increasing, and conversely, the 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 is transmitted as is to the input shaft 2 via this lock-up clutch (in the lock-up state). In the latter open state, the slip of the lock-up torque converter 3 (relative rotation of the pump impeller 3P and the turbine runner 3T) is 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 sun gear 4S and IJ song gear 4R.
.

A normal simple planetary gear set consisting of a pinion 4P meshing with these and a carrier 4C rotatably supporting the pinion 4P is used, and 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 human power 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 human power shaft 2 can be connected to the human power shaft 2 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 as a friction element for engine braking, and is prevented from being reversed (rotation in the opposite direction to the engine) via a row one-way clutch LO/C. Ring gear 4R is carrier 5C
The sun gear 5S is integrally coupled to the output shaft 6, and the sun gear 5S is coupled to the human power 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 FD/C moves ring gear 5R in the reverse direction (
It shall be connected to the carrier 4C in the direction opposite to the rotation of the engine).

High clutch H/C, reverse clutch R/C, low reverse brake R/B, overrun clutch O
The R/C and the forward clutch F/C are each operated by the supply of hydraulic pressure to perform the above-mentioned appropriate coupling and fixing, but the band brake B/B is particularly configured as shown in FIG. 3. That is, the service piston 8 and the piston 9 are slidably fitted into the housing 10 to set the 2nd speed servo apply chamber 2S/A, the 3rd speed servo release chamber 3S/R, and the 4th speed servo apply chamber 43/A. .

A spring 11 is compressed between both pistons 8.9 to restrain them to the farthest position from each other as shown in the figure, and while maintaining this relative position, both pistons 8.9 are urged to the non-operating position by a spring 12. support In this configuration, when the second speed selection pressure P2 is supplied to the second speed servo apply chamber 2S/A, the piston 8 moves to the left in the figure together with the piston 9, and the handbrake B/B is activated by tightening the brake band 13. Operate. In this state, 3 is also placed in the 3rd speed servo release chamber 3S/R.
When the speed selection pressure P3 is supplied, the piston 8 moves to the right in the figure depending on the magnitude of the pressure receiving area, and the band brake B/B becomes inactive due to the relaxation of the brake band 13. Thereafter, when the 4th speed selection pressure P4 is also supplied to the 4th speed servo apply chamber 4S/A, the piston 9 is moved to the left in the figure independently, and the band brake B/B is activated by tightening the brake band 13.

The power transmission train in Figure 2 consists of 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, friction elements FD/C, L
Together with the appropriate operation 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 shaft 60 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 addition, in the following table, the ∆ mark indicates activation (hydraulic inflow), and the ∆ mark indicates the friction element that should be activated when engine braking is required.And, as shown in the △ mark, the overrun clutch OR/C is activated. While this is happening, the forward one-way clutch FD/C placed in parallel with this becomes inactive,
Of course, while the low reverse brake and R/B are in operation, the low one-way clutch and O/C disposed in parallel therewith are inactive.

FIG. 1 shows that the engine brake control device of the present invention is installed in a hydraulic circuit for controlling the speed change of the power transmission train, and this hydraulic circuit includes a pressure regulator valve 20, a pressure modifier valve 22, a duty solenoid 24,
Pilot valve 26, torque converter regulator valve 2
8. Lockup 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 pressure accumulator 46.3-2 timing valve 48.
4-2 relay valve 50.4-2 sea fence valve 52, I
Range pressure reducing valve 54, shuttle valve 56, overrun clutch control valve 58, third shift solenoid 60, overrun clutch pressure reducing valve 62. 2nd speed servo apply pressure accumulation rake 64, servo charger valve 65
．． 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 the aforementioned torque converter 3 and forward clutch F/C.

High clutch H/C, band brake B/B, reverse clutch R/C, low reverse brake LR/B,
Overrun clutch OR/C and oil pump 0/
It is configured by connecting to P as shown in the figure.

The pressure regulator valve 20 includes a spool 20b elastically supported at the left half position in the figure by a spring 20&, and a plug 20c abutting against the lower end surface of the spool in the figure. Basically, the oil pump 0/P is connected to the circuit 71. The oil discharged to the line is regulated to a certain 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 to do. For this purpose, the pressure regulator valve 20 is connected to the circuit 71 via a damping orifice 72.
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 ports 20 to 20h are provided which are opened and closed according to the stroke position of the spool 20b. Port 20e is connected to circuit 71, and is arranged so that as spool 2Qb descends from the left half position in the figure, it communicates with 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 decreases, and at the point when the communication with the port 20g is cut off, the port 20e
Place it so that it begins to communicate with the Then, the port 20f is connected to the capacity control actuator 75 of the oil pump O/P via a circuit 74 having 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 eccentricity is controlled by the actuator 75.
It is assumed that when the pressure toward the capacitor exceeds a certain value, the capacitance is reduced. The plug 20c of the pressure regulator valve 20 receives modifier pressure from a circuit 76 on its lower end surface in the figure, and receives a circuit 77 on its pressure receiving surface 20i.
It is assumed that the spool 20b receives a backward selection pressure from the spool 20b, and applies an upward force in the drawing corresponding to these pressures to the spool 20b.

The pressure regulator valve 20 is normally located on the left side e in the figure.
state, and when oil is discharged from the oil pump 07P, this oil flows into the circuit 71. At the left half position of the spool 20b, 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, causing the spool 20b to
20e to 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 #20 basically makes 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. And, as will be explained later, modifier pressure occurs when the reverse is selected, and increases in proportion to the engine load (engine output torque), so the above line pressure increases when the engine load does not increase when the reverse is selected. The price will increase accordingly.

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 the line pressure remains at the desired constant level when reversing is selected. value. When the rotation speed of the oil pump 0/P reaches a certain number of revolutions or more (the engine speed exceeds a certain number of revolutions), the oil discharge amount that increases accordingly becomes excessive, and the pressure in the circuit 71 becomes higher than 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 2Of 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 the port 20f and the bleed 73, but a feedback pressure is generated within the 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. Thus, the oil pump O/P operates while the rotational speed exceeds a certain value.
The amount of oil discharged is controlled to be constant, and engine power loss is prevented from increasing due to more oil being discharged than necessary.

The line pressure generated in the circuit 71 as described above is supplied to the pilot valve 26, the manual valve 36, and the 3rd speed servo release pressure accumulation rake 66 by the line pressure circuit 78, and is also supplied to the forward clutch pressure accumulator 46 by the circuit 96.

The pilot valve 26 includes a spool 26b elastically supported in the upper half position in the figure by a spring 26a, with the end face of the spool 26b far from the spring 26a facing 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.
6d shall be switched and connected.

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 26c 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 of the figure,
The circuit 79 is cut off from the circuit 78 and at the same time is connected to the drain port 26d. 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 solenoid 24, 34, the lockup control valve 30, 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 communicates with the drain port 24C. This duty sononoid 24 has a coil 24a turned on and off at a constant cycle by a computer (not shown), and an O
The circuit 81 is controlled by the ratio of N time (deity ratio).
A control pressure according to the duty ratio is generated within. 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 capo 22C to which the circuit 76 is connected. A manual port 22d for connecting the pilot pressure circuit 79 and a drain boat 22e are provided, and the circuit 76 is connected to the chamber 22f facing the end face of the spool 22tl that is far from the spring 22&.

Then, at the left half position of the spool 22b in the figure, exactly the boat 2
These ports are arranged so that 2C is isolated from ports 22d and 22e.

The pressure modifier valve 22 receives the spring force from the spring 22a and the force from the control pressure from the circuit 81 downward in the figure on the spool 22b, and the pressure modifier valve 22 receives the spring force from the spring 22a and the force from the control pressure from the circuit 81 downward in the figure.
The force due to the output pressure from 22C is received by the spool 22h upward in the figure, and the spool 22b is stroked to a position where these forces are balanced. 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, port 22C leads to port 22d, and circuit 79
The output pressure is increased by replenishing the pilot pressure from the 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 port 22c communicates with the drain port 22e, and the output pressure is reduced. By repeating this action, the pressure modifier valve 22 regulates the output pressure from the port 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 the modifier pressure in the circuit. Pressure regulator valve 2 from 76
0 plug 20c. 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. The pressure rises as the engine load increases except when reverse is selected, and becomes 0 when reverse is selected.
This enables the above-mentioned line pressure control by the valve 20.

The torque converter regulator valve 28 includes a spool 28b elastically supported in the right half position in the figure by a spring 28a.
Port 28C is connected to port 28d while the spool strokes between the right half position in the figure and the left hand position in the figure, and as the spool 28b rises from the left half position in the figure, port 28C is connected to port 28d. It is assumed that the degree of communication is decreased and the degree of communication is increased for the port 28e. Spring 28 is used to control the stroke of spool 28b.
The chamber 28F facing the spool end face far from a is the spool 28
It communicates with the port 28C through the communication hole 28g provided in b. The port 28C is connected to a predetermined lubricating part via a relief valve 82 and connected to the lock-up control valve 30 via a circuit 83, and the port 28d is connected via a circuit 84 to port 2 of the pressure regulator valve 20.
0h, and 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 port 2gC
is connected to a circuit 83 via an orifice 87, and an oil cooler 89 and a predetermined lubricating section 90 are connected by a circuit 88.
Let me understand. A circuit 10 branching from the circuit 88
3 is also connected to the lock-up control valve 30.

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 pressure regulator valve 20 via the circuit 84, this oil is supplied from the circuit 83 to the torque converter as described later. 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 23b to rise in the figure against the spring 28a. When the spool 28b rises from the left-hand 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 a lubricating section 90. 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.

Lockup control valve 30Lk spool 30a
'' and the plug 30b coaxially abutted against each other, and when the spool 30a is at the limit position shown in the right half, the circuit 83 is connected to the circuit 91 from the torque converter release chamber 3R, and the circuit 103 is connected to the circuit 85, Spool 30
When the spool 3Qa is lowered to the left half position in the figure, the circuit 83 is connected to the circuit 85, and when the spool 3Qa is further lowered, the circuit 91 is connected to the drain port 30C. In order to control the stroke of the spool 30a, the plug 3
The end face of the spool 30a far from 0b faces the chamber 30d, and the pressure of the circuit 91 is led through the orifice 92 to the chamber 30e where the end face of the plug 30b far from the spool 30a faces. Note that the circuit 93 from the torque converter apply chamber 3A is connected to the circuit 85 at a location 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 a downward force in the figure, thereby preventing pulsation of the spool 30a.

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, and the circuits 93°85 and 103 under pressure regulation by the torque converter regulator valve 28, and is removed from the circuit 88. Thus, the torque converter 3 transmits power in the converter state. As the pressure in the chamber 30d decreases, the spool 30a is lowered in the figure via the plug 30b by the pressure from the orifice 92, 94, and when it has further descended from the left half position in the figure,
Pressure regulating oil from circuit 83 goes to circuit 85.93, apply chamber 3A, release chamber 3R1 circuit 91, drain port 30
C, and the torque converter 3 enters the chamber 30.
Power is transmitted in a slip control state in which the slip decreases as the pressure in d decreases. From this state, room 30d
When the internal pressure is further lowered, the circuit 91 is completely communicated with the drain port 30c due to further lowering of the spool 30a, the pressure in the release chamber 3R is brought to O, and the torque converter 3 transmits power in a lock-up state. In addition, in such a limited slip state and a lock-up state, a part of the oil passes through the orifices 86 and 87 to the oil cooler 89.
This compensates for the cooling of the oil.

The symmetry valve 32 determines the pressure to the chamber 30d that controls the stroke of the lock-up control valve 30.
A spool 32b is elastically supported by a spring 32a at a lower half position in the figure, and this spool is appropriately switched to an upper half position in the figure by the pressure inside a chamber 32c.

And sea? ) When the spool 32b is in the lower half position in the figure, the loop valve 32 connects the circuit 95 from the poem 30d to the pilot pressure circuit 79, and when the spool 32b is in the upper half position in the figure, the circuit 95 is connected to the circuit 97. shall be allowed to do so.

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 3 by a computer (not shown).
4a is controlled to be turned ON and OFF at a constant cycle, and the ratio of the ON time to the constant cycle (duty ratio) is controlled to generate a control pressure in the circuit 97 according to the duty ratio. Shuttle valve 32 is in the upper half state as shown in circuit 97.
When the control pressure 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 increase ability and torque fluctuation absorption function of the torque converter 3 are absolutely necessary, the duty ratio is set to 0%, thereby controlling the control pressure of the circuit 97 to the original pressure. Make it the same as the pilot pressure of a certain circuit 79. At this time, the control pressure maintains the spool 30a in the right half position in the figure in the chamber 30d, and maintains the torque converter 3 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.
0, the torque converter 3 is operated in a slip control state that matches the demand, and the above-mentioned side of the torque converter 3 is operated.

When the engine is under low load and high rotation speed, when the function is not required, the duty ratio is set to 100%, and thereby the control pressure is set to O to maintain the torque converter 3 in the lockup state as required via the lockup control valve 30.

Note that when the shuttle valve 32 is in the lower half state in the figure, the chamber 30d
Pilot pressure is supplied from the circuit 79 to keep the lock-up control valve 30 in the right-hand half state in the figure, so that the torque converter 3 always functions in the converter state.

The manual valve 36 can be set in the parking (P) range, reverse (R) range, neutral (N) range, or
Forward automatic transmission (0) range, forward 2nd gear engine brake (II) range, forward 1st gear engine brake (I)
A spool 36a that is stroked in a range is provided, and the line circuit 78 is configured as shown in the following table according to the selected range of the spool.

36R. Note that in this table, O 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, and this spool is connected to the chamber 3.
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 has a spool 38b.
When the spool 38b is in the left half position, the port 38d is connected to the drain port 38, the port 38f is connected to the port 38g, and the port 38h is connected to the port 38. When the spool 38b is in the right half position in the figure, the port 38d is connected to the port 38J. , port 38
It is assumed that f is connected to port 38k and port 38h is connected to port 38β.

The second shift valve 40 corresponds to a certain shift valve in the present invention, and includes a spool 40b elastically supported at the left half position in the figure by a spring 40a, and this spool is connected to the chamber 4.
When supplying pressure to 0C or the pressure receiving surface 40 of the spool 40b
When applying lunge (low speed engine brake) pressure, which will be described later, to β, it is assumed to be in the right half position in the figure. When the spool 40b is in the left half position in the figure, the second shift valve 40 changes the port 40d to the drain port 40e and the port 40f to the drain port 40e.
are connected to port 40g, port 40h is connected to drain port 401 with orifice, and when spool 40b is in the right half position in the figure, port 40d is connected to port 40J, port 40f is connected to drain port 40e, and port 40h is connected to port 40k. They shall be able to communicate with each other.

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 lenses are controlled electronically by coils 42a, 44a and plunger 42b, respectively.
, 44b and springs 42d and 44d. The first shift solenoid 42 is connected to the pilot pressure circuit 79 via an orifice 99, and the circuit 1 leading to the chamber 38c.
00 from the drain port 42C when the coil 42a is ON (energized) to make the control pressure in the circuit 100 the same value as the pilot pressure, which is the source pressure.
8 is to be switched to the right half state in the figure. Further, the second shift slide/id 44 is connected to the pilot pressure circuit 79 via the orifice 101, and is connected to the pilot pressure circuit 79 through the orifice 101, and is connected to the pilot pressure circuit 79 through the orifice 101.
02 is the drain port when the coil 44a is ON (energized))
44c to make the control pressure in the circuit 102 the same value as the pilot pressure of the source pressure, and thereby the second shift valve 40
is switched to the state shown in the right half of the figure.

These shift solenoids 42. 44 ON, OFF
The first to fourth forward speeds can be obtained by the combination of the above and, therefore, the states of the shift valves 38 and 40, which are summarized in the following table.

In Table 3, the O mark in this table indicates the state of the right half of the shift valve in the figure, and the x mark indicates the state of the left half of the shift valve in the figure, and the ON and OFF states of the shift solenoids 42 and 44 are not shown. A computer determines a suitable gear position from the vehicle speed and engine load based on a predetermined gear change pattern, and determines the appropriate gear position.

The forward clutch pressure accumulator 46 is constructed by pressing a service piston 46a to the right half position in the figure by a spring 46b, and a chamber 46C defined between both ends of the service piston is opened to the atmosphere, and a chamber 46C defined between both ends of the service piston is opened to the atmosphere. The radial end faces face the closed chambers 46d and 46e, respectively. Chamber 46d is connected to circuit 71 by circuit 96, and line pressure is supplied to chamber 46d as accumulation back pressure. Further, the chamber 46e is connected to the forward clutch F/C by a circuit 104.

The forward clutch F/C is connected to the port 360 of the manual valve 36 by a circuit 106, and a one-way orifice 107 is inserted into the circuit 106, which exerts a throttling effect only on the hydraulic pressure directed toward the forward clutch F/C.

3-2 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 the port 4 with a port 48C and an orifice 48f is opened.
8d, the pressure inside the chamber 48e is high, and the spool 4
It is assumed that when port 8b is in the right half position in the figure, ports 48C and 486 are 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 port 50C is connected to the drain port 50d with an orifice, and pressure is supplied into the chamber 50e. When the spool 50b is in the right half position in the figure, connect 50C to port 50f.
This shall lead to the following.

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 port 52C is connected to a drain port with an orifice.
2d, the pressure inside the chamber 52e is high and the spool 52
When b is in the left half position in the figure, port 52C is connected to port 52.
It is assumed that it leads to f.

■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 has ports 54c and 54d that communicate with each other at this spool position, and the spool 54b is biased toward the left half position in the figure. A drain port 54e is provided which begins to communicate with the port 54C when the port 54d is closed. Spool 5 far from spring 54a
The chamber 54f facing the end face of the cylindrical member 4b is connected to the port 54c via the orifice 108. Thus, the range pressure reducing valve 54 is normally in the right half state in the figure, and when pressure is supplied to the port 54d, pressure is output from the port 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 is lowered to more than the left half position in the drawing due to this decrease in output pressure, the port 54C communicates with the port 54d, and the output pressure from the bow 54C is increased. 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 6g, when the upward force in the figure due to the pressure from the port 56c exceeds a certain value, it is stroked to the right half position in the figure. At the left half position in the figure, the port 56d is connected to the circuit 109 of the third shift solenoid 60, and the port 56e is connected to the drain port 56f.
Port 56d is located at the right half position in the figure.
Assume that the port 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 60
It is assumed that the control pressure in the circuit 109 is made to be 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) as described later.

The overrun clutch control valve 58 has a spring 58a.
The 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, and when this pressure is relieved, or when the pressure is supplied to the chamber 58c on the opposite side.
When pressure is supplied to 8i, it is assumed to be in the left half position in the figure.

Also, the spool 58b is located at the left half position in the figure, with the port 58d connected to the drain port 58e, and the port 58f connected to the port 58g.
port 58d and port 5 at the right half position in the figure.
8h, and the port 58f is connected to the drain port 58e.

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 62c 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 62e. This output pressure is
[When the spool 62b is fed back to the 1st shift corresponding to the spring force of the spring 62a, the spool 62b is moved to the right half position in the figure.) 62d.

626 and connect port 62e to drain port 6.
2g, and the overrun clutch pressure reducing valve 62 reduces the output pressure from the port 62e to a constant value determined by the spring force of the spring 62a.

The 2-speed servo apply pressure accumulator 64 includes a service piston 64a elastically supported in the left half position in the figure by a spring 64b, and a chamber 6 defined between both ends of the service piston 64a.
4C is opened to the atmosphere, and the small diameter end face and large diameter end face of the service piston are made to face the closed chambers 64d and 64e, respectively.

The servo charger valve 65 includes a spool 65b elastically supported in the right half position in the figure by a spring 65a, and when this spool receives pressure from the port 65c into the chamber 65d, it is in the left half position in the figure. This spool position shall be maintained when pressure is supplied from bow 1-65e as well. Then, bow at the right half position in the figure of the spool 65b) 65
The ports 65f and 65g are cut off, and the ports 65f and 65e are opened at %J in the left half of the figure, and the ports 65f and 65e are interconnected.

The third-speed servo release pressure accumulation rake 66 is constructed by elastically supporting a service piston 66a at the left half position in the figure by a spring 66b, and connects a chamber 66C defined between both ends of the service piston to the line pressure circuit 78. The small diameter end face of the service piston is placed in the drain chamber 66d, and the large diameter end face is placed in the sealed chamber 66e.

The 4-speed servo apply pressure accumulator 68 is constructed by elastically supporting a service piston 68a at the left half position in the figure by a spring 68b, and defines a sealed chamber 68c between both ends of the service piston, and a small-diameter end face of the service piston. and large-diameter end faces facing the sealed chambers 68d and 68e, respectively.

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 port 70e at the left half position in the figure, and when the control pressure to the chamber 70c increases and the spool 70b rises above the right half position in the figure, the boat 70d is connected to the circuit 1.
It is assumed that the circuit 105 is switched and connected to a circuit 105 branched from 06. Then, the output capacitor) 70d is connected to the accumulator chambers 64d and 68C by the circuit 111, and the spring 7
It is also connected to the chamber 70F that accommodates 0a.

Thus, the accumulator control valve 70 appropriately raises the spool 70b to the right half position in the figure or higher by the control pressure applied to the chamber 70c except when the rear A is selected. As a result, if the forward clutch F/C is in operation (while traveling forward as shown in Table 1 above), the forward clutch pressure (
line pressure) is output to the circuit 111, and this circuit 111
When the internal pressure 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.
As the engine output torque (engine output torque) increases, the output torque from the circuit 111 to the chamber 64d of the accumulator 64.
The pressure supplied to 68c 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 360 of the manual valve 36 to the forward clutch F/C is connected halfway to the port 38g of the first shift valve 38 and the port 40g of the second shift valve 40. Along with connecting,
Shuttle valve 5 via circuit 112 branched from circuit 106
It is also connected to port 56C of No. 6 and port 58g of overrun clutch control valve 58.

The port 38f of the first shift valve 38 is connected to the port 50f of the 4-2 relay valve 50 through a circuit 113, and is also connected to the accumulator chamber 64e and the 2-speed servo apply chamber 2S/A via the one-way orifice 114.
50f is also connected to chamber 32C of shuttle valve 32 by circuit 115. Furthermore, port 3 of the first shift valve 38
8h is connected to the chamber 50e of the 4-2 relay valve 50 by the circuit 116.
and connected to port 58h of overrun clutch control valve 58, 4-2 port 50 of relay valve 50.
C is connected to the port 40k of the second shift valve 40 by the circuit 117.
Connect to.

38β is connected to the port 38 of the first shift valve 38, together with the port 40f of the second shift valve 40, to the high clutch [1/C] by a circuit 118, and a pair of one-way orifices 119. 120
Insert. 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 3-2 timing valve 4 by connecting ports 48c and 48d inside.
8 is inserted into this circuit 123. Connect the circuit 124 branched from the circuit 121 between the one-way orifice 122 and the third-speed servo release chamber 3S/R to m52e of the 4-2 sea fence valve 52, and connect the ports 52c and 52f of the 4-2 sea fence valve 52. port 38i of the first shift valve 38 and port 40 of the second shift valve 40, respectively.
Connect to h. Also, the boards 65f and 65g of the servo charger valve 65 are connected to the circuit 113 so as to bypass the one-way orifice 114, and the port 65C is connected to the circuit 118.

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.
d is connected to one artificial boat of the shuttle ball 127 by a circuit 126. The other artificial port of the shuttle ball 127 is connected by a circuit 128 to the port 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. , the exit port of shuttle ball 127 is connected by circuit 130 to low reverse brake LR/B. Second shift valve 40
Port 40 of the range pressure reducing valve 54 is connected to the port 54 of the range pressure reducing valve 54 by the circuit 131 as the low speed stage holding circuit in the present invention.
C and chamber 54, and connect port 54d of range pressure reducing valve 54 to port 3 of manual valve 36 through circuit 132.
Connect to 6I.

Port 56e of Yattle valve 56 is connected to 3 by circuit 133.
-2 Connected to the chamber 48e of the timing valve 48 and connected to the port 56
d is connected to chamber 58C of overrun clutch control valve 58 by circuit 134. Port 58d of overrun clutch control valve 58 is connected by circuit 135 to accumulator chamber 68e and four-speed servo apply chamber 4S/A through one-way orifice 136, and chamber 58j is connected to circuit 132 by circuit 150.

The port 58f of the overrun clutch control valve 58 is connected to the port 62d of the overrun clutch pressure reducing valve 62 by a circuit 137, and the port 62e of the pressure reducing valve 62 is connected to the port 62d of the overrun clutch pressure reducing valve 62 by a circuit 138.
Connected to the R/C, a check valve 139 is provided between circuits 137 and 138. Overrun clutch pressure reducing valve 62 (
The D-hole 62c is connected to the port 36* of the manual valve 36 and the chamber 56g of the shuttle valve 56 by a circuit 140.

The operation of the above hydraulic circuit will be explained next.

The pressure regulator valve 20, the pressure modifier valve 22, and the duty solenoid 24 operate as described above to regulate the oil from the oil pump O/P to a line pressure that increases in proportion to the engine output torque, except when selecting reverse, and when selecting reverse. At the same time, the oil from the oil pump O/P is kept constant and output to the circuit 78°96.

The line pressure to the circuit 78 reaches the pilot valve 26, manual valve 36, U and accumulator 66, and the accumulator 66 is in the right half state in the figure. Also, the line pressure to the circuit 96 reaches the accumulator 46, placing it in the right half state in the figure. Accumulator control valve 7
0 supplies accumulator back pressure proportional to the engine output torque to the chambers 64d and 68C of the accumulators 64 and 68 through the circuit 111 due to the aforementioned action during forward gear stage selection when the forward clutch F/C is operated, and controls these accumulators. They are shown in the right half of the figure. Incidentally, when the backward movement is selected, the accumulator control valve 70 sets the accumulator back pressure to 0 as described above, and the accumulator 64.
68 is shown in the left half state in the figure. Also, Kusaku Lotben 2
6 is a circuit 79 that maintains a constant pilot pressure through the above action.
Output to.

If the P or N range driver does not wish to drive and sets the manual valve 36 to the P or N range, the manual valve boat 36D, 3
6 II, 36I, and 36R all serve as drain ports as shown in Table 2 above, and line pressure is not output from these ports, so the forward clutch 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, allowing the power transmission train in FIG. 2 to remain in a neutral state in which no power can be transmitted.

When D range forward travel is desired and the manual valve 36 is set to D range, automatic gear shifting is performed as follows.

(First speed) In the D range, the manual valve 36 outputs the line pressure from the circuit 78 to the port 36D as shown in Table 2 above. The line pressure from port 36D is supplied as D range pressure by circuit 106 to port) 38g of first shift valve 38, port) 40g of second shift valve 40, and forward clutch F/C. It is supplied to port 56G of valve 56 and port 58g of overrun clutch control valve 58.

On the other hand, when the vehicle is stopped in the D range, the computer automatically switches between the first shift solenoid 42 and the second shift solenoid 44.
are both ON, the first shift valve 38 and the second shift valve 11
0 is in the right half state in the figure. Therefore, the high clutch H/C is communicated from the circuit 118 to the drain port 40e via the port 4Of, and becomes inoperative. Also, 2nd speed servo apply chamber 2S/A is connected to port 38f from circuit 113.

38k, circuit 118, connected to drain port 40e via port 40f, and 3rd speed servo release chamber 3S/R connected to circuit 1
21゜118, drain port 40e via port 40f
The band brake B
/B is also inactive. That is, while the engine output torque is above a certain level, the D range pressure (line pressure) from the port 56C, which is proportionally high, causes the shuttle valve 56 to be in the right half state in the diagram, and the overrun clutch control valve 58 is output from the circuit 134. The pilot pressure of the circuit 79 is supplied to the valve 5.
8 to the right half state in the figure. Further, even when the engine output torque is below a certain level and the shuttle valve 56 is in the left half state in the figure, if there is no engine brake request operation, which will be described later, then the circuit 1
The computer turns on the third shift solenoid 60 to set the control pressure flowing from 09 to the overrun clutch control valve 58 through the circuit 134 to the same value as the pilot pressure, and brings the overrun clutch control valve 58 to the right half state in the figure. . Therefore, at this time, the 4th speed servo apply pressure 4S/A is in circuit 135, port 5gd, 5gh
, circuit 116, port 38h, 38β, circuit 118
, Drain port 40e as above via port 1-4Of
This will lead to.

Further, the reverse clutch R/C is drained from the port 36R via the circuit 128 and is in an inoperative state, and the low reverse brake LR/B is also drained as described below and is in an inactive state. That is, one inlet circuit 128 leading to the shuttle ball 127 related to the circuit 130 to the low reverse brake LR/B is drained as described above, and the other circuit 126 is also drained thereto. i, circuit 125, ports 4Qd, 40j, communicated via circuit 131■ Range pressure reducing valve 54 is connected to manual valve port 3
Since it is not receiving pressure supply from 6), it is in the right half state in the figure and is drained from port 361, so the low reverse brake LR/B is in an inoperative state as described above. Next, the overrun clutch OR/C is operated by the check valve 13 from the circuit 138 because the overrun clutch control valve 58 is in the right half state in the figure as described above.
9. It communicates with the drain port 58e through the port 58f and is in an inactive state.

Therefore, as for the friction element, only the forward clutch F/C is operated by the D range pressure from the circuit 106, and as shown in Table 1 above, the forward one-way clutch F/C is operated.
Coupled with the operation of the D/C, the automatic transmission shifts to the first gear selection state. At this time, the torque converter 3 is put into the converter state as shown below, so the selection of the first gear and the stop can be maintained. Also, the forward clutch F/C
The hydraulic pressure is throttled by the one-way orifice 107, and the accumulator piston 46a is moved by the spring 46b.
Since the rear pressure in the chamber 46d is pushed up against the back pressure of the engine, this rise is done slowly, and the progress of the forward clutch F/C operation is gradual, resulting in a shift from the N or P range to the D range. It can alleviate the selection shock when using the microwave.

As mentioned above, since there is no pressure in the circuit 113 heading towards the 2-speed servo apply chambers 2S and /A, the shuttle valve 32 to which the chamber 32G is connected to this circuit via the circuit 115 is in the lower half state in the figure. . Therefore, the shuttle valve 32 supplies the pilot pressure from the circuit 79 to the chamber 30d from the circuit 95, keeps the lock-up control valve 30 in the right half state in the drawing, and puts the torque converter 3 in the converter state. Therefore, the vehicle can be stopped even in the first gear, and the vehicle can be started by increasing the engine output torque by depressing the accelerator pedal.

(Second speed) After that, when the vehicle speed increases and the driving state becomes such that the second speed should be selected, the computer switches the first shift solenoid 42 to OFF as shown in Table 3 above, and the first shift valve 3
8 to the left half state in the figure. This causes the first shift valve 38 to continue draining the circuit 126 by connecting it to the drain port 38e, and draining the circuit 116 to the drain port 38h, 38h.
i and 4-2 Sea fence valve 52 (this valve is currently in the right half state in the figure because no pressure is supplied to the 3rd speed servo release chamber 3S/H) port) 52c to the drain port 5
Continue to drain by passing through 2d. However, first shift valve 38 connects circuit 113 to circuit 106;
The D range pressure is also supplied to the 2nd speed servo apply chamber 2S via the circuit 113, which operates the band brake B/B, maintains the operation of the forward clutch F/C, and operates the forward one-way clutch FO/C. In combination, the automatic transmission enters the second speed selection state, as is clear from Table 1 above.

However, since the servo charger valve 65 is in the right half state in the figure during the first speed, even if the D range pressure is introduced into the circuit 113, this pressure causes the servo charge valve 65 to be in the left half state in the figure. There is no problem with the shift shock mitigation effect described below.

During this upshift from 1st speed to 2nd speed, the hydraulic pressure to the 2nd speed servo apply chamber 2S/A is throttled by the one-way orifice 114, pushing the accumulator piston 64a located at the right half position in the figure as described above. Since the band brake B/B gradually rises while moving, the operation of the band brake B/B proceeds gradually, and the shock at the time of the gear change can be alleviated. Then, the chamber 6 surrounding the accumulator piston 64a
Since the back pressure within 4d is proportional to the engine output torque as described above, the shift shock reducing effect described above can be reliably achieved.

Note that, as is clear from Table 1 above, not only the second speed but also the third and fourth speeds are selected, the second speed servo apply chamber 2S
Since the D range pressure is supplied to /A, the shuttle valve 32, which supplies this pressure to the 32C through the circuit 115, maintains the upper half state in the figure during selection of the second to fourth speeds. As a result, the lock-up control valve 30 is supplied with the control pressure of the circuit 97 to its chamber 30d during the second to fourth speed selection, and this control pressure is determined by the computer via the duty solenoid 34 as described above. The lock-up control valve 30 can put the torque converter 3 into a converter state, a slip control state, or a lock-up state to match the operating conditions by the above operation.

(Third speed) After that, when the operating state becomes such that the third speed should be selected, the computer turns off the second shift solenoid 44 as shown in Table 3 above, and puts the second shift valve 40 in the left half state in the figure. . As a result, the D range pressure that had reached port 40g passes through port 40f, circuit 118, one-way orifice 120, and then one-way orifice 11.
9 and supplied to the high clutch H/C, which is activated. At this time, the pressure in the circuit 118 is
5d, the servo charger valve 65 is placed in the left half state in the figure, and the ports 65f and 65g, which bypass the one-way orifice 114, are communicated, and this state is called port).
The pressure is maintained at the D range from the circuit 113 via 65f and 65e. On the other hand, this pressure passes directly through the one-way orifice 122 via a circuit 121 branched from the circuit 118, and is also applied to the third-speed servo release chamber 3S/R to deactivate the band brake B/B. As is clear from FIG. 3 when inactive, the piston 8 moves to the right in the figure to reduce the volume of the second-speed servo apply chamber 2S/A, but the oil flow accompanying this can pass through the one-way orifice 114. Furthermore, since the servo charger valve 65 communicates between the ports 5f and 65g as described above, no stress is caused to the operation of the band brake B/B. Pressure cover 4-2'/- for the chamber 52e of the 3rd speed servo release chamber 3S/R, the valve is placed in the left half position in the figure, and the port 52c is communicated with the port 52f.
The second shift valve 40 connects this port 52f to the drain port 4
0i, so circuit 116 continues to drain. Therefore, the high clutch H/C is activated and the band brake B/B is deactivated, and as is clear from Table 1 above, the automatic transmission engages the forward one-way clutch FO/C and is switched to the third position. You can choose the speed.

Note that during this upshift from 2nd speed to 3rd speed, the high clutch H/C and 3rd speed servo release chamber 3S
The pressure to /R is throttled by the one-way orifice 119 and increases while pushing away the accumulator piston 66a, which is in the right half of the figure, against the line pressure in the chamber 66C, so that the shock at the time of gear shifting is reduced. It can be prevented.

(4th speed) After that, when the operating state becomes such that 4th speed should be selected, the computer turns the first shift solenoid 42 to O as shown in Table 3 above.
N, and the first shift valve 38 is switched to the right half state in the figure. As a result, the first shift valve 38 cuts off the circuit 113 to the 2nd speed servo apply chamber 2S/A from the D range pressure circuit 106, but continues to connect to the circuit 118 at the port 38k and continues to the D range pressure circuit 113 to the 2nd speed servo apply chamber 2S/A. While supplying range pressure, the circuit 126 is cut off from the drain port 38e, but it is connected to the circuit 125 at the port 38J,
By passing through this and leading to the drain port 40e, the circuit 1
Continue to drain 26. The first shift valve 38 further communicates the circuit 116 to the circuit 118 via ports 38h, 38β, circuit 118+' 116, ports 58h,
58d, by supplying the D range pressure to the 4-speed servo apply chamber 4S/A via the circuit 135 and the one-way orifice 136, the band brake B/B is switched to the operating state, and the forward clutch F/C and high clutch H/ In order to maintain the operation of C, the automatic transmission is set to the fourth position as shown in Table 1
Can be set to quick selection state.

In this upshift from 3rd speed to 4th speed, the 4th speed selection pressure (highest speed selection pressure) to the 4th speed servo apply chamber 4S/A is throttled by the one-way orifice 136, as described above. Since the accumulator piston 68a in the right half state in the figure gradually rises while being pushed away against the back pressure in the chamber 68c, it is possible to prevent shock during the shift. Since the back pressure in the chamber 68c applied to the accumulator piston 68a is proportional to the engine output torque as described above, the above-mentioned shift shock reducing effect can be reliably achieved.

(4→3 downshift) When the operating state becomes such that 3rd gear should be selected while the 4th gear is being selected, the computer turns off the first shift solenoid 42 and shifts to the 1st shift, as is clear from Table 3 above. The valve 38 is switched to the left half state in the figure. As a result, the state is the same as when the third speed was selected, and the pressure in the fourth speed servo apply chamber 4S/A passes through the one-way orifice 136 and is immediately removed from the drain port 401, causing a downshift to the third speed. can be done.

(4-2 Downshift Shift) During the selection of the 4th speed, when the operating state becomes such that the 2nd speed should be selected, the computer turns off the first shift solenoid 42 and turns the first shift valve 38 off, as is clear from Table 3 above. At the same time as switching to the left half state in the figure, the second shift solenoid?
Turn i4 ONL to switch the second shift valve 40 to the right half state in the figure. By switching the first shift valve 38, the connection of the circuit 113 to the second speed servo apply chamber 2S/8 from the circuit 118 to the circuit 106 is changed, and the pressure is continuously supplied to the second speed servo apply chamber 2S/A.

Further, by switching the second shift valve 40, the circuit 118 is cut off from the D range pressure circuit 106 and communicated with the drain port 40e. Therefore, the operating pressure of the high clutch H/C passes through the one-way orifice 119, is throttled by the one-way orifice 120, and is removed from the drain port 40e through the circuit 118, and is removed from the third-speed servo release chamber 3S.
The pressure in /R is also eliminated through the same route after being throttled by the one-way orifice 122.

By the way, the pressure of 3rd speed servo release chamber 3S/H is connected to circuit 1.
The 4-2 sequence valve 52, which is guided by and responds to the pressure 24, maintains the left half state in the figure until the pressure is released, and connects the port 52C, which communicates with the circuit 116 via ports 1-38i and 38h, to the drain port. 52d and continues to communicate with port 52r. Therefore, the pressure in the 4th speed servo apply chamber 4S/A connected to the circuit 116 is not removed, and the pressure in the 3rd speed servo release chamber 3S/R is maintained until the pressure in the 3rd speed servo release chamber 3S/R is removed. During this time, the pressure in the 4-speed servo apply chamber 4S/A is supplied to the 4-2 relay valve 50 via the circuit 116, and this valve is maintained in the right half state in the figure. Therefore, the pressure in the circuit 113 to the 2-speed servo apply chamber 2S/A is as follows: ports 5Qf, 50C, circuit 117, port HOk,
40h, 52f, 52c, 38i,
38h and circuit 116, ports 513h, 58d
, the pressure inside the 4-speed servo apply chamber 4S/A is maintained via the circuit 135.

When the pressure in 3rd speed servo release chamber 3S/R is released, 4
-2 sequence valve 52 is in the right half state in the figure, and the port 52c is connected to the drain port 52d, and the pressure in the 4-speed servo apply chamber 4S/A connected to the circuit 116 is removed from the drain port 52d. As a result of this removal, the 4-2 relay valve 50 enters the left half state in the figure, and removes the pressure in the circuit 117 from the drain port 50d. Thus, during the shift, the pressure in the 4th gear servo apply chamber 4S/A will be removed after the pressure in the 3rd gear servo release chamber 3S/R and high clutch H/C is released, and the pressure in the former will be eliminated. This prevents the pressure from being released before the latter pressure and shifting from 4 to 3 to 2, making it possible to reliably shift from 4 to 2.

(3→2 downshift shift) When the operating state becomes such that the second speed should be selected in the third speed selection state, the computer turns on the second shift solenoid 44 to shift to the second The valve 40 is switched to the right half state in the figure.

Due to this switching, even if port 40h is connected from drain port 401 to port 40, circuit 116 is connected at third speed.
(4-speed servo apply chamber 4S/A) is 4-2 in an unpressurized state.
Since the relay valve 50 is in the left half state in the figure and the circuit 117 is connected to the drain port 50d, the port 52f becomes the drain port, and the 4-2 sequence valve 52 is connected to the 4-speed servo apply chamber regardless of the state. Keep 4S C in an unpressurized state.

On the other hand, the above-mentioned switching of the second shift valve 40 connects the circuit 118 to the drain port 40e, and the pressure in the high clutch H/C and the 3rd speed servo release chamber 3S/R is changed to the above-mentioned path for the 4-2 shift. Eliminate after a while.

Therefore, a downshift from 3rd speed to 2nd speed is obtained, but at this time, the pressure in the 3rd speed servo release chamber 3S/R is removed at a predetermined timing according to the engine operating condition as shown below. , allowing smooth gear shifting.

That is, when the engine output torque is below a certain level, the corresponding low D range pressure (line pressure) from the port 56c causes the shuttle valve 56 to be in the left half state in the figure, and the chamber 48e of the 3-2 timing valve 48 is Since it communicates with the drain port 56r via the circuit 133 and the port 56e, the 3-2 timing valve 48 is in the left half state in the figure. Therefore, under this low engine output torque, the 3rd speed servo release chamber 3S
The pressure of /R is discharged not only through the one-way orifice 122 but also through the orifice 48f, and the discharge speed is fast.

When the engine output torque is above a certain level, the correspondingly high D range pressure (line pressure) from the port 56C puts the shuttle valve 56 in the right half state in the figure, and the 3-2 timing valve 48 receives the pressure from the circuit 109. The state changes depending on the control pressure.

The computer turns on the third shift solenoid 60 under this engine output torque and at a predetermined vehicle speed or higher.
Set the control pressure to the same value as the pilot pressure, which is the source pressure. Therefore, the 3-2 timing valve 48 is in the right half state in the figure, and the 3-2 timing valve 48 is in the right half state in the figure.
To release the pressure in the speed servo release chamber 3S/R, the speed is set to a low speed using only the one-way orifice 122.

With the exhaust pressure of the 3rd speed servo release chamber 3 S/R, the piston 8 is moved to the left in FIG. 3 by the pressure inside the 2nd speed servo apply chamber 2 S/A. However, during this time, the 2nd speed servo apply chamber 2
As the volume of S/A increases, the oil flow is caused by the state of the left half of the servo charger valve 65 in FIG. 1 (one-way orifice 11).
4), the operation is carried out without stress, and it is possible to prevent the engine from racing due to a delay in the operation of the band brake B/B and slippage of the band brake B/B.

(2→1 downshift shift) When the operating state in which the 1st speed should be selected in the 2nd speed selection state is reached, the computer turns on the first shift solenoid 42 and controls the first shift valve 38 as shown in Table 3 above. Switch to the right half state in the figure. As a result, the circuit 6113 to the 2nd speed servo apply chamber 23/8 is transferred to the D range pressure circuit 106.
38f.

38k to circuit 118. By the way, circuit 118
is connected to the drain port 40e by the second shift valve 40, the pressure in the second speed servo apply chamber 2S/A passes through the one-way orifice 114 and is quickly removed, resulting in a downshift from second speed to first speed. You can get variable speed.

(Overdrive Prohibited) If the driver does not wish to upshift to 4th gear (overdrive) and wishes to drive with engine braking in 3rd gear, he turns on the OD prohibition switch (not shown) in the driver's seat. In response to this signal, the computer turns the first and second shift solenoids 42 and 44 on and off in accordance with the combinations shown in Table 3, depending on the operating state, but so as not to select the fourth gear. Control. Thus, the automatic transmission can shift between the first speed and the third speed using the same function as in the D range.

In the third speed, the computer turns off the third shift solenoid 60 and sets the control pressure to the circuit 109 to zero. Here, the engine output torque is small (a state in which engine braking is required), and the D range pressure (line pressure) from the low port 56C corresponding to this cannot bring the shuttle valve 56 to the right half state in the figure. If it is in the half state, the control pressure of the circuit 109, which is set to 0 as described above, will become the control pressure of the circuit 134.
Even when the overrun clutch control valve 58 is reached, this valve is placed in the left half state in the figure. Therefore, circuit 1
D range pressure from 12 passes through circuit 137 and overrun clutch pressure reducing valve 62 to overrun latch OR/C.
By operating this, as is clear from Table 1 above, it is possible to run with engine braking in the third gear. During this engine braking operation, the overrun clutch pressure reducing valve 62 reduces the working pressure of the overrun clutch OR/[: by the pressure regulating action since no pressure is coming out from the manual valve port) 36I[:, and its capacity is adjusted to the demand. Match this to reduce engine brake shock. Note that when the engine output torque is large and engine braking is not required, the shuttle valve 56 is in the right half state in the figure due to the high D range pressure from the port 56C, and the overrun clutch control valve 58 is activated by the pilot pressure from the circuit 79. In the right half of the figure, the overrun clutch OR/C is not activated and the engine brake is disabled. At this time, the pressure in the overrun clutch OR/C is quickly removed from the drain port 58e via the check valve 139, and there is no delay in its removal.

■If the range driver desires engine braking in 2nd speed and sets the manual valve 36 to ■range, this manual valve will be connected not only to port 36D but also to circuit 7B from port 36H as shown in Table 2 above. Outputs line pressure. Pressure is supplied from port 36D through the same route as in the case of the D range described above, and the computer is supplied with pressure from the first. Second
Set the shift solenoids 42 and 44 to the first position according to Table 3 above.
The automatic transmission can be shifted between the first speed and the second speed by turning the switch ON and OFF so as to obtain the first speed or the second speed.

The pressure from the manual valve port 36 (■) (range pressure) passes through the circuit 140 and reaches the port 62c of the overrun clutch pressure reducing valve 62, placing this valve in the left half state in the figure. The range pressure from the circuit 140 further reaches the chamber 56g of the shuttle valve 56, locking this valve in the left half state in the figure. In this state of the shuttle valve 56, the circuit 110 is connected to the chamber 58c of the overrun clutch control valve 58.
control pressure is supplied, and the computer uses this control pressure as the second
0 through turning off the third shift solenoid 60 during speed selection.
The overrun clutch control valve 58 is in the left half state in the figure. Thus, D from circuit 112
Range pressure is in circuit 137, overrun clutch pressure reducing valve 6
2 and the overrun clutch 0RIC via circuit 138
This means that engine braking in second gear is possible.

At this time, the overrun latch pressure reducing valve 62 does not perform any pressure reducing action because it is in the locked state as described above, and the capacity of the overrun clutch OR/C is increased to meet the demand, and the overrun clutch OR/C is prevented from slipping. This can prevent the engine brake from becoming less effective.

While selecting the first speed, the computer turns the third shift solenoid 60 to [1N] to make the above control pressure the same value as the pilot pressure, which is the original pressure, and puts the overrun clutch control valve 58 in the right half state in the figure. .

As a result, the pressure in the overrun clutch OR/C is reduced by the check valve 139. Drain port 5 via port 58f
8e, and the overrun clutch OR/C becomes inactive, resulting in the same state as in the case of D range 1st speed.

■When the range driver desires engine brake driving in 1st gear (low gear) and sets the manual valve 36 to I range (low gear engine brake range), this manual valve is connected to port 361 as shown in Table 2 above. ).

The line pressure of the circuit 78 is output to 36■ and 36I. Pressure is supplied from port 36D through the same route as in the case of the D range described above, and the computer
Set the shift solenoids 42 and 44 to the first position according to Table 3 above.
The automatic transmission can be shifted between 1st and 2nd speeds by turning I]N and (]FF so that 2nd speed or 2nd speed is obtained. The reason why this is sometimes selected is to prevent over-revving of the engine at high vehicle speeds when the engine is reversely driven from the wheels in the range while driving. Then, first shift to second gear, and then shift to first gear at a vehicle speed that does not cause overspeeding of the engine.

The pressure from the manual valve port 36■ is applied by keeping the shuttle valve 56 and the overrun clutch pressure reducing valve 62 in the left half state in the figure, as in the case of the range ■ described above, and the overrun clutch control valve 58 from the circuit 109. The state is changed by control pressure.

By the way, the computer sets this control pressure to 0 by turning off the third shift solenoid 60 in the range 1, and operates the overrun clutch OR/C by keeping the overrun clutch control valve 58 in the left half state in the figure. continue.

The pressure from the manual valve port 36I (low speed engine brake range pressure) passes through the circuit 132 and reaches the range pressure reducing valve 54. This valve reduces the pressure from the circuit 132 to a constant value by the above action and outputs it to the circuit 131. do. By the way, the second shift valve 40 is electronically controlled to be in the right half state in the figure as shown in Table 3, regardless of whether it is in the first or second gear.
The pressure in circuit 131 is output to circuit 125. On the other hand, the first
At the second speed, the shift valve 38 is in the left half state in the figure as shown in Table 3 above, and cuts the pressure in the circuit 125 and also cuts the pressure in the circuit 1.
26 to the drain port 38e. Thus, the circuit 130 to the low reverse brake LR/B is connected to the drain port 38e via the shuttle ball 125 and the circuit 125, and the low reverse brake LR/B is inactive. Therefore, operation of the overrun clutch OR/C enables engine braking running in the second speed.

As mentioned above, when the vehicle speed reaches a point where the engine does not overspeed even in 1st gear, it becomes 1st gear.
The shift valve 38 is in the right half state in the figure, and the circuit 125 is connected to the circuit 126, and the pressure that reaches the circuit 125 is transferred to the circuit 1.
°26. The shuttle ball 1271 is supplied to the low reverse brake LR/B via the circuit 130 to operate it. Thus, as described above, in conjunction with the fact that the overrun clutch OR/C is activated, it is possible to run with engine braking in the first gear.

Note that during engine braking in 1st and 2nd speeds, the overrun clutch pressure reducing valve 62 is locked in the left half state in the figure as described above, so it does not perform any pressure reducing action and the overrun clutch OR/ The operating pressure (capacity) of C is kept high to meet the demand, and the overrun clutch OR/C is
This prevents engine braking from becoming less effective due to slippage. Also, during running with engine braking in the first gear, the pressure toward the low reverse brake LR/B is reduced to a predetermined value by the pressure reducing action of the Lunge pressure reducing valve 54, so that the capacity of the low reverse brake is adjusted to meet the demand. This can prevent engine brake shock from occurring.

By the way, the I range pressure from the circuit 131 acts on the spool pressure receiving surface 4H of the second shift valve 40, and the spool 40tl
The function is to maintain the state in the right half of the figure. Therefore, even if the electronic control system of the second shift valve 40, that is, the electronic control system of the second shift solenoid 44 fails and the shift valve 40 cannot be brought into the right half state in the figure, the shift valve state is changed to the I range. This can be ensured by pressure, and the above-mentioned action makes it possible to reliably obtain engine braking at the corresponding gear.

Further, the lunge pressure of the circuit 131 reaches the chamber 58i via the circuit 150, and serves to maintain the overrun clutch control valve 58 in the left half state in the figure. Therefore, even if the electronic control system of this valve 58, that is, the electronic control system of the third shift solenoid 60, fails and the valve 58 cannot be placed in the left half state in the figure, this state can be ensured by the lunge pressure and overrun occurs. Clutch OR/C is enabled to operate, and the above action ensures engine braking at the corresponding gear.

R range When the driver desires to drive in reverse and sets the manual valve 36 to the R range, this manual valve outputs the line pressure of the circuit 78 only to the port 36R as shown in Table 2 above. The pressure from port 36R (reverse selection pressure) passes through circuit 128, is throttled by one-way orifice 129, and is then supplied to reverse clutch R/C to actuate it.
It also reaches the chamber 68d of the accumulator 68. On the other hand, the pressure output to the circuit 128 is supplied to the low reverse brake LR/B through the circuit 130 while pushing the shuttle ball 127, and also operates the low reverse brake LR/B. Thus, the automatic transmission can select the reverse gear, as is clear from Table 1 above.

At this time, after the pressure to the reverse clutch R/C is throttled by the one-way orifice 129, the working piston 68a of the accumulator 68 is moved to the left half position in the figure at the same time as the manual valve 36 is set to the R range. Since the reverse clutch R/C can be operated at a predetermined speed, the reverse clutch R/C can be operated at a predetermined speed, and when switching from P or N range to R range, Select shock can be reduced.

When the manual valve 36 is switched from the R range to another range to stop backward travel, the port 36R becomes a drain port and the pressure of the reverse clutch R/C is removed. The low reverse braking is performed quickly by passing through the one-way orifice 129, and there is no delay in R/B non-operation.

(Effects of the Invention) Thus, as described above, the engine brake control device of the present invention is capable of shifting to a low speed gear (the right half state in FIG. 1) of a certain electronically controlled shift valve (second shift valve 40). 1st speed or 2nd speed) can be selected, and in the low engine brake range of the manual valve (36) (1st speed engine brake range in the illustrated example), the shift valve is electronically controlled to the specific state. At the same time, the friction element for the engine brake (lower hearth brake LR/B) receives the low speed engine brake range pressure (from the manual valve (36)).
■In automatic transmissions that are operated by the range pressure) to provide engine braking in low gears, the low gear engine brake range pressure is guided to the above-mentioned shift valve to bring it into the specific state mentioned above. Low speed stage holding circuit (1
31), even if the electronic control system of the shift valve breaks down and cannot be brought into the specified state (low gear cannot be selected), this specific state will be maintained at the low gear. This can be obtained by the low speed engine brake range pressure guided by the circuit, and even in the event of the failure, the low speed can be selected reliably, and the engine brake in the low speed can be compensated.

[Brief explanation of drawings]

Fig. 1 is a shift control hydraulic circuit diagram of an automatic transmission equipped with the engine brake control device of the present invention, Fig. 2 is a schematic diagram showing the power transmission train of the automatic transmission, and Fig. 3 is a band diagram of this power transmission train. FIG. 3 is a sectional view of the brake. 1... Engine output shaft 2... Input shaft 3... Torque converter 4... First planetary gear set 5... Second
Planetary gear set 6...Output shaft H/C...High clutch B/B...Band brake R/C...Reverse clutch R/B...Low reverse brake (friction element for engine brake) LO/C... Row one way clutch OR/C...
Overrun clutch F/C...Forward clutch FD/C...Forward one-way clutch 0/P.
...Oil pump 20...Pressure regulator valve 22...Pressure modifier valve 24, 34...
・Duty solenoid 26...Pilot valve 28...Torque converter regulator valve 30...
Lock-up control valve 32...Nyatle valve 36
...Manual valve 361, I range pressure (
Low speed engine brake range pressure) output port 38...First shift valve 40...Second shift valve (a certain shift valve) 42...First shift solenoid 44...Second shift solenoid 46...・Forward clutch pressure akinimulator 48・
...3-2 timing valve 50...4-2 relay valve 5
2...4-2 Sequence valve 54...■ Range pressure reducing valve 56...Shuttle valve 5
8...Overrun clutch control valve 60...
・Third shift solenoid 62... Overrun clutch pressure reducing valve 64... 2nd speed servo apply pressure accumulator 65 servo charger valve 66... 3rd speed servo release pressure accumulator 68.
... 4-speed servo apply pressure accumulator 70 ... Akinimulator control valve 131 Low speed stage holding circuit

Claims (1)

[Scope of Claims] 1. A low gear can be selected in a specific state of a certain electronically controlled shift valve, and in a low gear engine brake range of a manual valve, the certain shift valve is electronically controlled in the specific state. In the automatic transmission, the engine braking friction element is actuated by the low gear engine brake range pressure from the manual valve to provide engine braking in the low gear. An engine brake control device for an automatic transmission, comprising a low gear holding circuit that guides range pressure to the certain shift valve and maintains the shift valve in the specific state.