JPH01199048A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To set the changeover timing of a cutback valve freely and prevent excessive speed change shock by providing independent controllability for changing over of a shift valve and a cutback valve by using a single solenoid valve. CONSTITUTION:When a signal from an electronic control device 58 changes over a solenoid valve 56 from No.1 to No.2 oil pressure output condition, only a cutback valve 40 is changed over from the high line pressure position to low line pressure position, while a 1-2 shift valve 10 is held in the low speed position. Thereby first the line pressure is changed over to the low pressure condition, and when No.3 oil pressure is put out, the shift valve 10 is changed over to the high speed position. Thus the same speed change position is attained with No.1, No.2 oil pressures, but the condition of the cutback valve 40 is different, so that the cutback valve 40 can be controlled by the same solenoid valve 56 independently from the shift valve 10. Thus a low oil pressure condition is attained surely during speed change, and thereby excessive speed change shock is prevented.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention is directed to a control device for an automatic transmission.

(b) Conventional technology As a conventional automatic transmission control device, Japanese Patent Application Laid-Open No. 59-1
There is one shown in Publication No. 80149. The automatic transmission control device shown in this figure has a pressure regulator valve, a cutback valve, a shift valve, and a solenoid valve, and when the solenoid valve operates, the line pressure regulated by the pressure regulator valve is brought into a high pressure state. It is configured to switch to a low pressure state. In other words, 1-
When the 2nd shift valve is switched, the No. 15 pressure from the 1-2 shift valve acts on the cutback valve to switch it and change the pressure regulation state of the pressure regulator valve from a high pressure state to a low pressure state. Therefore, the cutback valve will be indirectly controlled by the solenoid valve.

(8) Problems to be Solved by the Invention However, the conventional automatic transmission control device as described above is basically configured so that the cutback valve is switched in conjunction with the operation of the 1-2 shift valve. Therefore, it is not possible to set the switching timing of the cutback valve independently of the 1st-2nd gear shift, and in some cases, the line pressure drop may be delayed, resulting in large shift stains. There is. In other words, if the 1st and 2nd gear shifts are performed relatively quickly, but the switching of the cutback valve and the associated change in the pressure regulator valve's pressure regulation state are delayed, the line pressure may not be sufficient. The 1st or 2nd gear shift may be started before the engine speed drops, causing a large shift stain. The present invention aims to solve these problems in 1.1.

(D) Means for Solving the Problems The present invention independently operates both a shift valve and a cutback valve using one solenoid valve.
By making i11 control possible, the above problem is solved. That is, the automatic transmission control device according to the present invention has the following features:
A solenoid valve (56) that outputs one-sided pressure, an electronic control device (58) that provides an electric signal to the solenoid valve, and a spool that switches between high and low gears of an automatic transmission. at least one shift valve (10) that switches between a corresponding high speed gear position and a low gear position by a switching signal pressure, a pressure regulator valve (70) that adjusts line pressure, and a pressure regulator valve (40). The spool of the cutback valve has a high line pressure position corresponding to a high line pressure state and a low line pressure position corresponding to a low line pressure state. The electronic control device uses the first hydraulic pressure (P, ), which is different in magnitude, as the switching signal pressure by the solenoid valve.
At least 3 of the second hydraulic pressure (P3) and the third hydraulic pressure (P4)
It is possible to output electricity No. 18 to adjust the hydraulic pressure of the stages,
The first hydraulic pressure is set to such a value that when it is output, the spool of the shift valve is placed in the high speed position, and the spool of the cutback valve is placed in the low line pressure position.
The second hydraulic pressure is set to such a level that when it is output, the spool of the shift valve is placed in the low gear position and the spool of the cutback valve is placed in the low line pressure position.
The third hydraulic pressure is set to a magnitude that, when output, causes the spool of the shift valve to be placed in the low gear position and the spool of the cutback valve to be placed in the high line pressure position.

Note that the symbols in parentheses indicate corresponding members in the embodiments described later.

(e) When the solenoid valve is operated by the electrical signal from the operating electronic f, IJ control device and the first hydraulic output state is switched to the second hydraulic output state, only the spool of the cutback valve changes from the high line pressure position to the low line pressure position. The spool of the - direction shift valve is held at the low speed position. As a result, the line pressure is first switched from a high pressure state to a low pressure state, and then when the third hydraulic pressure is output, the shift valve is switched from a low gear position to a high gear position. In this way, the gear position is the same when the first hydraulic pressure is output and when the second hydraulic pressure is output, but what about the state of the cutback valve?
They are very different. This allows the cutback valve to be controlled independently of the shift valve by the same solenoid valve.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3 of the accompanying drawings.

FIG. 2 shows a schematic diagram of the power transmission mechanism of an automatic transmission with three forward speeds and one reverse speed. This power transmission mechanism consists of a human power shaft (■) to which the rotational force from the engine output shaft E is transmitted via the torque converter T/C, an output shaft (O) which transmits the driving force to the final drive device, a second planetary gear (G3), and a second planetary gear (G3). It has gear set G2, high and reverse clutch H&R/C, forward clutch F/C, band brake 810-and reverse brake L&R/B, and one-way clutch OWC. The first play E, tkl ill L set G, is composed of a sun gear S1, an internal gear R8, and a carrier PC3 that supports a binion gear Pl that meshes with both gears SI and R at the same time, and a planetary gear set G2 is , Sun Gear S2, and Internal Gear R
2, and a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. Each component is connected as shown. The power transmission mechanism is a high and reverse clutch H&R/C,
Each element (Sl,
S2, R, , R2, PC, and pc,) can be changed, and by this, the rotational speed of output shaft 0 relative to the rotational speed of human power shaft I can be carefully changed to achieve 3rd gear forward speed and 1st reverse speed. Obtainable.

FIG. 1 shows only the parts of the hydraulic circuit that are directly related to the present invention. The 1-2 shift valve 10 is composed of a spool 12 and a spring 14, and when the spool 12 is in the half position in the figure, it communicates the oil passage 16 with the oil passage 18, and when it is in the upper half position in the figure, it communicates with the oil passage 16. Drain 18.

The position of the spool 12 is determined by the balance between the hydraulic force acting on the boat 22 from the oil passage 20 and the force exerted by the spring 14. A manual valve 24 is installed in the oil passage 16.
Line pressure is always supplied when proceeding from 111 to 111. Note that the oil passage 16 is also connected to the forward clutch F/C.

The 2-3 shift valve 26 is composed of a spool 28 and a spring 30, and when the spool 28 is in the upper half position in the figure, it connects the oil passage 18 and the oil passage 32, and when the spool 28 is in the lower half position in the figure, it communicates with the oil passage 32. drain. The position of the spool 28 is determined by the balance between the hydraulic force acting on the boat 34 from the oil passage 20 and the force exerted by the spring 30. The oil passage 18 is connected to a servo apply chamber S/A for engaging the band brake B.

The oil passage 32 in which the orifice 31 is provided is connected to the high and reverse clutch H&R/C and the servo release chamber S/
Connected to R.

The cutback valve 40 is composed of a spool 42 and a spring 44. When the spool 42 is in the lower half position in the figure, the oil passage 33 and the oil passage 38 communicate with each other, and in the upper part position in the figure, the oil passage 38 communicates with the spool 42. It is drained and the oil passage 33 is shut off. The position of the spool 42 is determined by the balance between the hydraulic force acting on the boat 46 from the oil passage 20 and the force exerted by the spring 44. Line pressure is always supplied to the oil passage 33 from a pressure regulator valve 70. The oil passage 38 is connected to a pilot pressure boat 71 of a pressure regulator valve 70. This oil path 3
The pilot pressure boat 71 to which 8 is connected is a boat that lowers the line pressure regulated by the pressure regulator valve 70 when hydraulic pressure is applied, and increases the line pressure when hydraulic pressure is no longer applied. .

The aforementioned oil passage 20 is connected via an orifice 52 to an oil passage 50 to which a constant pressure is always supplied from a pilot pressure valve 48. The oil passage 20 is provided with an opening 54, and a solenoid valve 5 that can open and close this opening 54
6 is provided. The duty ratio of the solenoid valve 56 is controlled by fA from an electronic control device 58. Thereby, the oil pressure in the oil passage 20 can be adjusted to a predetermined oil pressure commanded by the electronic control device 58.

The electronic control device 58 receives electric signals from a vehicle speed sensor 6o, a throttle opening sensor 62, etc.
Based on these, the electronic control unit 58 outputs a signal for adjusting the oil pressure in the oil passage 20 in four stages: P+, P2, P3, and P4. In addition, the magnitude of hydraulic pressure is P 4 > P 3
> P 2 > PI. On the other hand, the cutback valve 40 is set so that when the oil pressure of the boat 46 is below PA, it is in the state shown in the lower half of the figure, and when it is greater than PA, it is in the state shown in the upper half of the figure. Similarly, the 1-2 shift valve IO is set so that when the oil pressure of the boat 22 is P or less, it is in the state shown in the F half of the figure, and when it becomes greater than PB, it is in the state shown in the upper half of the figure. Also, 2-3
The shift valve 26 is also designed to be in the lower half of the figure when the hydraulic pressure acting on the boat 34 is less than PC, and to be in the upper half of the figure when it is greater than Pc. The magnitude of these oil pressures is set so that PA>Pa>Pc. Also, p, , p2, p3 and P4, and PA
, the relationship between pH and hydraulic pressure with PC is P4>
P A > P 3 > P n > P 2 > P
This is done so that c > P t . This relationship is illustrated in FIG. 3.

By setting the hydraulic characteristics as described above, speed change control and cutback valve 40 control can be performed.

First, regarding gear shifting, the oil pressure in the oil passage 20 is 24 or P3.
At this point, both the 1-2 shift valve IO and the 2-3 shift valve 26 are in the state shown in the upper half of the figure, and only the forward clutch F/C is engaged, resulting in the first speed state. Next, when the oil pressure in the oil passage 20 is set to 21, both the 1-2 shift valve 10 and the 2-3 shift valve 26 are in the upper part state in the figure. Therefore, in addition to the forward clutch F/C, hydraulic pressure is also supplied to the servo apply chamber S/A, and the band brake B is engaged, so that the automatic transmission enters the second speed state. Next, when the oil pressure in the oil passage 20 is set to 22, the 1-2 shift valve lO is in the state of the F half in the figure, while the 2-3 shift valve 26 is switched to the state in the upper half of the figure. Therefore, hydraulic pressure is supplied to the high-and-reverse clutch H&R/C and the servo release chamber S/R, resulting in the third speed state.

Further, the cutback valve 40 operates as follows.

That is, the position of the spool 42 of the cutback valve 40 is switched when the oil pressure of the oil passage 20 is P4 and P23. That is, at the oil pressure P4, the cutback valve 40 is in the upper state and the oil passage 38 is in the drain state, and conversely, at the oil pressure P3, the oil passage 33 and the oil passage 38 are in communication. When the oil passage 38 is drained, no oil pressure acts on the pressure reducing pilot pressure boat 71 of the pressure regulator valve 70, so the line pressure regulated by the pressure regulator valve 70 becomes a high oil pressure. When the cutback valve 40 is switched from this state and hydraulic pressure is supplied to the oil passage 38, the pressure regulator valve 70 becomes in a state where it regulates the low line pressure. The oil pressure of the oil passage 20 is P
4 or P3, the automatic transmission is the first
Since the vehicle is in the high speed state, the pressure regulation state of the pressure regulator valve 70 can be changed by switching the cutback valve 40 regardless of the speed change. Therefore, if the oil pressure P4 is switched to the oil pressure P3 immediately after the 1-2 gear shift command is output from the electric control device 58, the line pressure is switched from a high state to a low state just before the 1-2 f speed. It is possible to secure the necessary line pressure, and 1-
When a second gear shift is performed, the line bit can be reliably kept in a low state. This prevents excessive shift stains from occurring.

Note that when the solenoid valve 56 is no longer energized due to a failure such as a wire breakage, the oil pressure in the oil passage 20 becomes the lowest state, and is in the second speed and low in-pressure state. Therefore, even if the solenoid valve 56 suddenly breaks down while the vehicle is running, it will only shift to the second gear, so an iG situation in which the vehicle becomes uncontrollable will not occur, and the vehicle can continue to drive for the time being.

(g) Effects of the Invention As explained above, according to the present invention, switching of the shift valve and cutback valve is controlled by one solenoid valve, and both valves are independently controlled. Compared to the case where dedicated solenoid valves are used for both valves, the cost is reduced and the device is also made smaller. In addition, the shift valve and cutback valve can be controlled independently, so
The switching timing of the cutback valve can be freely set, the oil pressure is kept in a high oil pressure state until straight gear shifting, and the oil pressure is reliably kept in a low oil pressure state at the time of gear shifting, thereby preventing excessive gear shifting.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram of an automatic transmission, and FIG. 3 is a diagram showing hydraulic characteristics of the embodiment. 10...1-2 shift valve, 26...2-3 shift valve, 40...cutback valve, 56...
Solenoid valve, 58...electronic control device. 3rd 2-3 shift valve affix l inclusion pressure t”U)

Claims (1)

[Claims] A solenoid valve that outputs a switching signal pressure in response to an applied electrical signal, an electronic control device that provides an electrical signal to the solenoid valve, and a spool that outputs a switching signal pressure in accordance with an applied electric signal, and a spool that is configured to adjust the high and low gear positions corresponding to the high and low gears of the automatic transmission, respectively. It has at least one shift valve that is switched between the step position and the step position by a switching signal pressure, a pressure regulator valve that adjusts line pressure, and a cutback valve that controls the pressure regulation state of the pressure regulator valve, The spool of the cutback valve is configured to be switched by a switching signal pressure between a high line pressure position corresponding to a high line pressure state and a low line pressure position corresponding to a low line pressure state, and is controlled by an electronic control device. are the first hydraulic pressures of different magnitudes as the switching signal pressures by the solenoid valves,
It is possible to output an electric signal that adjusts the oil pressure in at least three stages of the second oil pressure and the third oil pressure, and when the first oil pressure is output, the spool of the shift valve is placed in the high speed position, and the spool of the cutback valve is set to the high speed position. is set to the low line pressure position, and the second hydraulic pressure is set to a size that, when this is output, sets the shift valve spool to the low gear position and also sets the cutback valve spool to the low line pressure position. The third oil pressure is set to a size that, when output, causes the shift valve spool to be in the low gear position and the cutback valve spool to be in the high line pressure position. Control device.