JP2664179B2 - Control device for automatic transmission - Google Patents

Description

The present invention relates to a control device for an automatic transmission.

(B) Conventional technology As a control device for a conventional automatic transmission, Japanese Patent Application Laid-Open No. 59-18014
There is one disclosed in Japanese Patent Publication No. 9 The control device of the automatic transmission shown here is a pressure regulator valve,
It has a cutback valve, a shift valve, and a solenoid valve, and is configured to switch a line pressure regulated by a pressure regulator valve between a high pressure state and a low pressure state by operation of the solenoid valve. That is, when the 1-2 shift valve is switched by the solenoid valve, the signal pressure from the 1-2 shift valve acts on the cutback valve to switch the cutback valve, thereby switching the pressure regulation state of the pressure regulator valve from the high pressure state to the low pressure state. . Therefore, the cutback valve is indirectly controlled by the solenoid valve.

(C) Problems to be Solved by the Invention However, the above-described conventional control device for an automatic transmission is basically configured such that the cutback valve is switched in conjunction with the operation of the 1-2 shift valve. Therefore, the switching timing of the cutback valve cannot be set independently of the 1-2 shift, and in some cases, the reduction of the line pressure is delayed, and a large shift shock may occur. That is, when the 1-2 shift is performed relatively quickly, while the switching of the cut-back valve and the change in the pressure regulation state of the pressure regulator valve associated therewith are delayed, the line pressure is sufficiently reduced. In some cases, the 1-2 shift is started before and a large shift shock is generated. An object of the present invention is to solve such a problem.

(D) Means for Solving the Problems The present invention solves the above-mentioned problems by enabling both the shift valve and the cutback valve to be independently controlled by one solenoid valve. That is, the control device for an automatic transmission according to the present invention includes a solenoid valve (56) that outputs a switching signal pressure in accordance with an applied electric signal, an electronic control device (58) that supplies an electric signal to the solenoid valve, and a spool. At least one shift valve (10) that switches between a high speed position and a low speed position corresponding to a high speed position and a low speed position of the automatic transmission, respectively, by a switching signal pressure; and a pressure regulator valve ( 70) and a cut-back valve (4
0), and the spool of the cut-back valve switches 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 by a switching signal pressure. The electronic control unit is configured to switch at least three stages of a first hydraulic pressure (P ₁ ), a second hydraulic pressure (P ₃ ), and a third hydraulic pressure (P ₄ ) having different magnitudes as switching signal pressures by a solenoid valve. Can output an electric signal for adjusting the hydraulic pressure. The first hydraulic pressure is set to a size such that when this signal is output, the spool of the shift valve is set to the high speed position and the spool of the cutback valve is set to the low line pressure position. When the second hydraulic pressure is output, the second hydraulic pressure is set to a value such that the shift valve spool is set to the low speed position and the cutback valve spool is set to the low line pressure position. The third hydraulic pressure is set to such a value that when the third hydraulic pressure is output, the spool of the shift valve is set to the low speed position and the spool of the cutback valve is set to the high line pressure position. In addition, the code | symbol in a parenthesis shows the corresponding member of the Example mentioned later.

(E) Operation When the solenoid valve is operated by an electric signal from the electric control device and the third hydraulic output state is switched to the second hydraulic output state, only the cut-back valve spool moves from the high line pressure position to the low line pressure position. Switching, while the spool of the shift valve is held in the low gear position. As a result, first, the line is switched from the high pressure state to the low pressure state, and then when the first hydraulic pressure is output, the shift valve is switched from the low speed position to the high speed position. As described above, the same shift stage is obtained when the third hydraulic pressure is output and when the second hydraulic pressure is output, but the state of the cutback valve is different from each other. Thus, the cutback valve can be controlled by the same solenoid valve independently of the shift valve.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a skeleton diagram showing a power transmission mechanism of an automatic transmission having three forward speeds and one reverse speed. This power transmission mechanism includes an input shaft I to which torque from an engine output shaft E is transmitted via a torque converter T / C, an output shaft O to transmit driving force to a final drive device, a first planetary gear set G ₁ , It has a two planetary gear set G ₂ , a high and reverse clutch H & R / C, a forward clutch F / C, a hand brake B, a low and reverse brake L & R / B, and a one-way clutch OWC. The first planetary gear set G ₁ includes a sun gear S ₁ , an internal gear R _1, and a carrier PC ₁ that supports a pinion gear P ₁ that meshes with both gears S ₁ and R ₁ simultaneously. set G ₂ is a sun gear S _2, the internal gear R _2, and a double gear S ₂ and R ₂ simultaneously meshing pinion gear P ₂ the supporting carrier PC ₂ Prefecture. Each component is connected as shown. The power transmission mechanism operates the planetary gear set G ₁ by operating the high and reverse clutch H & R / C, the forward clutch F / C, the band brake B, and the low and reverse brake L & R / B (one-way clutch OWC) in various combinations.
And the rotation state of each element of G ₂ (S ₁ , S ₂ , R ₁ , R ₂ , PC ₁ and PC ₂ ), whereby the rotation speed of the output shaft O with respect to the rotation speed of the input shaft I can be changed. It is possible to obtain three forward speeds and one reverse speed by various changes.

FIG. 1 shows only a portion of the hydraulic circuit directly related to the present invention. 1-2 shift valve 10 is spool
The spool 12 connects the oil passage 16 and the oil passage 18 at the lower half position in the drawing, and drains the oil passage 18 at the upper half position in the drawing. The position of the spool 12 is determined by the balance between the force of the oil pressure acting on the port 22 from the oil passage 20 and the force of the spring 14. The line pressure is always supplied to the oil passage 16 from the manual valve 24 during forward movement. Oil passage 16 is a forward clutch
It is also connected to F / C.

The 2-3 shift valve 26 has a spool 28 and a spring 30
When the spool 28 communicates with the oil passage 18 and the oil passage 32 at the upper half position in the drawing, the spool 28 drains the oil passage 32 at the lower half position in the drawing. The position of the spool 28 is determined by the balance between the force of the hydraulic pressure acting on the port 34 from the oil passage 20 and the force of 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 provided with the orifice 31 is connected to the high and reverse clutch H & R / C and the servo release chamber S / R.

The cutback valve 40 includes a spool 42 and a spring 44
The oil passage 33 and the oil passage 38 communicate with each other when the spool 42 is at the lower half position in the drawing, and the oil passage 38 is drained and the oil passage 33 is shut off at the upper half position in the drawing. . spool
The position of 42 is determined by the balance between the force by the hydraulic pressure acting on the port 46 from the oil passage 20 and the force by the sampling 44. The line pressure is always supplied to the oil passage 33 from the pressure regulator valve 70. The oil passage 38 is connected to a pilot pressure port 71 of the pressure regulator valve 70. Pilot pressure port to which this oil passage 38 is connected
Reference numeral 71 denotes a port for reducing the line pressure regulated by the pressure regulator valve 70 when the oil pressure is applied, and increasing the line pressure when the oil pressure is not applied.

The 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 56 that can open and close the opening 54 is provided. The duty ratio of the solenoid valve 56 is controlled by a signal from the electronic control unit 58. Thereby, the oil pressure of the oil passage 20 can be adjusted to a predetermined oil pressure commanded by the electronic control device 58.

Vehicle speed sensor 60 to the electronic control unit 58, an electrical signal from a throttle opening sensor 62 is inputted, the electronic controller 58 P ₁ the hydraulic pressure in the oil passage 20 on the basis of these, P _2,
And it outputs a signal for adjusting the four stages of the P ₃ and P _4. Incidentally, the hydraulic pressure of the size is as _{P 4> P 3> P 2} > P 1. On the other hand, the cut-back valve 40 is a hydraulic port 46 becomes the state of the lower half in the drawing when: P _A, are set so as to be in the state of half the top in the drawing when it becomes greater than P _A. Similarly 1-2 shift valve 10 is also the oil pressure of the port 22 becomes the state of the lower half in the drawing when: P _B, there are set to a state of half the top in the drawing when it becomes greater than P _B . Also, 2-3 shift valve
Hydraulic pressure acting on the port 34 becomes the state of the lower half in the drawing when: P _C also 26, are set to be state of the upper half of the in the figure when it becomes greater than P _C. The magnitudes of these oil pressures are set so that P _A > P _B > P _C. Also, P ₁ , P ₂ ,
And P ₃ and P _4, the hydraulic pressure of the magnitude of the relationship between P _A, P _B and P _C,
P ₄ > P _A > P ₃ > P _B > P ₂ > P _C > P ₁ . This relationship is illustrated in FIG.

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

First, the speed change, the hydraulic pressure of the oil passage 20 becomes P ₄ or P _3, 1-2 shift valve 10 and 2-3 shift valve 26
Are in the upper half of the figure, and the forward clutch F /
Only C is fastened to the first speed state. Next, when the oil pressure of the oil passage 20 to P _1, the state of the 1-2 shift valve 10 and 2-3 lower half of the shift valve 26 both FIG. For this reason,
In addition to the forward clutch F / C, hydraulic pressure is also supplied to the servo apply chamber S / A, the band brake B is engaged, and the automatic transmission enters the second speed state. Next, when the hydraulic pressure in the oil passage 20 to P _2, 1-2 shift valve 10 is in a state of lower half in the drawing, whereas the 2-3 shift valve 26 is switched to a state of half the top in the drawing. For this reason, high and reverse clutch H & R /
Hydraulic pressure is supplied to C and the servo release chamber S / R to enter the third speed state.

The cutback valve 40 operates as follows.
That is, the position of the spool 42 of the cut-back valve 40 is switched in the hydraulic oil pressure in the oil passage 20 and the P ₄ and P _3. That is, hydraulic
P ₄ in the cut-back valve 40 is brought into such a state of the upper half portion, the oil passage 38 becomes the drain state, the oil passage 33 in the hydraulic P ₃ and the oil passage 38 and communicates with the opposite. Since the oil pressure does not act on the pressure reducing pilot pressure port 71 of the pressure regulator valve 70 when the oil passage 38 is drained, the line pressure regulated by the pressure regulator valve 70 is high. When the cutback valve 40 is switched from this state and the oil pressure is supplied to the oil passage 38, the pressure regulator valve 70 is in a state of adjusting a low line pressure. Also oil pressure in the oil passage 20 is a P _4, also be a P _3,
Since the automatic transmission is in the first speed state, the pressure adjustment state of the pressure regulator valve 70 can be changed by switching the cutback valve 40 regardless of the shift. Therefore, when switching the hydraulic pressure P ₄ to the hydraulic P ₃ immediately before the command from the electronic control unit 58 a 1-2 shift is outputted, it is possible to switch the line pressure immediately before the 1-2 shift from a high state to a low state , The required line pressure can be secured, and
When the -2 speed change is performed, the line pressure can be reliably reduced. This prevents an excessive shift shock from occurring.

If the solenoid valve 56 is not energized due to a failure such as a disconnection, the oil pressure in the oil passage 20 becomes the lowest state,
The second speed and the low line pressure state are set. Therefore, even if the solenoid valve 56 suddenly fails during traveling, the second
Since only the speed is increased, the situation that the vehicle cannot be controlled does not occur, and the traveling can be continued for the time being.

(G) Effect of the Invention As described above, according to the present invention, the switching of the shift valve and the cutback valve is controlled by one solenoid valve, and both valves can be controlled independently. Compared to the case where a dedicated solenoid valve is used for each valve, the price is reduced and the device is also downsized. Further, since the shift valve and the cut-back valve can be controlled independently, the switching timing of the cut-back valve can be freely set, a high oil pressure state is maintained just before shifting, and a low oil pressure state is ensured during shifting, An excessive shift shock can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a skeleton 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, 70 ... pressure regulator valve.

Claims (1)

(57) [Claims] 1. A solenoid valve for outputting a switching signal pressure according to an applied electric signal, an electronic control device for supplying an electric signal to the solenoid valve, and a spool corresponding to a high speed stage and a low speed stage of the automatic transmission, respectively. At least one shift valve that switches between a high speed position and a low speed position by a switching signal pressure, a pressure regulator valve that adjusts a line pressure, and a cutback valve that controls a pressure adjustment state of the pressure regulator valve. The cut-back valve spool is configured to switch 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 by a switching signal pressure. The electronic control unit transmits the first hydraulic pressure and the second hydraulic pressure having different magnitudes as the switching signal pressure by the solenoid valve. An electric signal for adjusting at least three levels of hydraulic pressure and a third hydraulic pressure can be output. When the first hydraulic pressure is output, the shift valve spool is set to the high speed position and the cutback valve spool is set to the low line. When the second hydraulic pressure is output, the second hydraulic pressure is set to a value that sets the shift valve spool to the low speed position and sets the cutback valve spool to the low line pressure position. The control device for the automatic transmission, wherein the third hydraulic pressure is set to a size such that when the third hydraulic pressure is output, the shift valve spool is set to the low gear position and the cutback valve spool is set to the high line pressure position.