JPH025947B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a hydraulic control device having a solenoid.

(B) Prior Art As a conventional hydraulic control device having a solenoid, there is, for example, an overdrive release valve and an overdrive release solenoid shown in Japanese Utility Model Application Publication No. 59-7954. This hydraulic control device uses an overdrive release solenoid to open and close an opening provided in a signal pressure oil path connected to a line pressure oil path via an orifice-type throttle valve, and the hydraulic pressure of this signal pressure oil path is The overdrive release valve is switched by the .
This allows the overdrive release valve to be switched depending on whether the solenoid is turned on or off.

(c) Problems to be Solved by the Invention However, in the conventional hydraulic control device as described above, even though the solenoid is open, a certain amount of hydraulic pressure is generated at low temperatures, and the valve does not operate as specified. There was a problem that there were cases. In other words, the openings opened and closed by the solenoid are relatively small so that they can be closed even with a small pushing force from a small solenoid, and there is a gap between the line pressure oil path and the signal pressure oil path. Due to the relationship between the throttling effect of the throttle valve provided and the throttling effect of this opening, a certain amount of oil pressure is generated in the signal pressure oil path even in normal conditions, but at low temperatures the viscosity of the oil increases and the oil flows smoothly. Because there is no signal pressure, higher pressure than normal occurs in the signal pressure oil path. If this pressure exceeds the switching pressure of the valve, the valve will switch even though the solenoid has not closed the opening. If such a hydraulic control device is applied to switching control of the lock-up mechanism of the torque converter of an automatic transmission, the lock-up mechanism will always be in operation at low temperatures, making it impossible for the vehicle equipped with the automatic transmission to run. This problem occurs. In order to reduce the oil pressure in the signal pressure oil path, the diameter of the throttle valve provided between the line pressure oil path and the signal pressure oil path can be made smaller to increase the throttling effect. The flow rate of oil passing through the valve decreases, and even if the opening is closed by the solenoid, the oil pressure in the signal pressure oil path does not rise immediately. In other words, the responsiveness of changes in oil pressure in the signal pressure oil path to on/off of the solenoid decreases. This will cause a problem.

The present invention solves the above-mentioned problems and provides a hydraulic control device that does not generate a residual pressure exceeding a predetermined level in the signal pressure oil passage at low temperatures and has sufficient responsiveness at normal operating temperatures. It is an object.

(d) Means for solving the problems The present invention solves the above problems by using a choke valve as the throttle valve. That is, the hydraulic control device having a solenoid according to the present invention is characterized in that the throttle valve that connects the signal pressure oil path to the oil pressure source oil path is a choke-type throttle valve that is longer in length than its cross-sectional area. On the other hand, the throttle valve provided in the opening opened and closed by the solenoid is an orifice type throttle valve.

(e) Effect By adopting the above configuration, the resistance of the choke valve increases as the viscosity of the oil increases at low temperatures, and the flow rate passing through it decreases. Since the flow rate of the throttle valve is not affected by the viscosity of the oil, the residual pressure generated in the signal pressure oil path is extremely small. Therefore, the occurrence of a problem in which the valve to which the oil pressure of the signal pressure oil path acts is switched irrespective of the operating state of the solenoid is prevented. On the other hand, when the oil temperature rises to the temperature during normal use, the resistance of the choke valve decreases as the viscosity of the oil decreases, so sufficient flow is not supplied from the line pressure oil path to the signal pressure oil path. However, since the viscosity of the oil has decreased, residual pressure above a predetermined level will not occur. Moreover, in this case, since a sufficient flow rate is supplied, the responsiveness of the oil pressure of the signal pressure oil path when the solenoid closes its opening is very good.

(f) Embodiment FIG. 2 shows a skeleton diagram of a transmission mechanism section of an automatic transmission with an overdrive to which the present invention is applied. This transmission mechanism section includes a torque converter section 1, an overdrive gear train section 2, and a third speed gear train section 3. The torque converter 4 with a lock-up mechanism of the torque converter section 1 receives torque from an engine (not shown) through a rotating shaft 4a, and outputs the torque to the overdrive gear train section 2 through a rotating shaft 4b. There is. The torque converter 4 with a lock-up mechanism has a lock-up clutch 4c, which allows the rotating shafts 4a and 4b to be mechanically connected. The overdrive gear train section 2 is
It has a planetary gear set 5, a direct clutch 6, and an overdrive brake 7, and the third speed gear train section 3 is a well-known gear train with three forward speeds and one reverse speed, and has two planetary gear sets 9 and 10, two clutches 11 and 12, two brakes 13 and 14,
and a one-way clutch 15, the brakes 7, 13, 14, one-way clutch 1
5 and clutches 6, 11, and 12 in appropriate combinations, four forward speeds and one reverse speed are realized.

FIG. 1 shows an entire hydraulic control system for an automatic transmission including a hydraulic control system according to the present invention. Hereinafter, valves and the like directly related to the present invention will be explained, and detailed explanations of other parts will be omitted. 23, 2-3 shift valve 24, 3-4 shift valve 25, pressure modifier valve 2
6, Throttle valve 27, Throttle backup valve 28, Solenoid downshift valve 29, Second lock valve 30, OD control valve 31, Governor valve 33, Accumulator 34
Regarding the structure and operation of
132062 and JP-A-58-196373.

The lockup control valve 32 is connected to the spool 32.
a and a spring 32b, and can be switched between a state in which the oil passage 68 communicating with the lock-up oil chamber 4d is connected to the oil passage 70 and a state in which it is connected to the drain port 72. Torque converter supply pressure is supplied to the oil passage 70 from the pressure regulator valve 21 . Switching of the lockup control valve 32 is accomplished by a lockup control solenoid 36. The lock-up control solenoid 36 switches the lock-up control valve 32 by controlling the discharge of hydraulic pressure from a signal pressure oil passage 74 branched from the line pressure oil passage 58 (hydraulic source oil passage) via a choke-type throttle valve 72. That is, lockup control solenoid 3
6 is off, the oil in the signal pressure oil passage 74 is discharged from the opening 80 provided with the orifice-type throttle valve, and no oil pressure acts on the port 76 of the lock-up control valve 32.
is in a position that communicates the oil passage 68 with the oil passage 70, and conversely, when the lock-up control solenoid 36 is turned on, the discharge of oil from the opening 80 is stopped, so that line pressure acts on the port 76 of the lock-up control valve 32. However, the lock-up control valve 32 is switched to drain the oil passage 68 from the drain port 72. Lockup control valve 32
In the state in which the oil passage 68 and the oil passage 70 are communicated, the same hydraulic pressure as the torque converter supply pressure acts on the lock-up oil chamber 4d, so the lock-up mechanism is in the released state, and the lock-up control valve 32 is in the oil passage 68. When the lock-up clutch 4c is switched to the lock-up state, the oil pressure in the lock-up oil chamber 4d is drained and the lock-up clutch 4c is engaged. The lockup control solenoid 36 is operated by a signal from a lockup control unit (not shown), for example, a fourth lockup control solenoid.
It is turned on when the vehicle speed is higher than a predetermined vehicle speed (or higher than a predetermined vehicle speed for each gear).

When the solenoid 36 is in the OFF state and the opening 80 of the signal pressure oil passage 74 is open, as described above, the line pressure oil passage 58 is connected to the signal pressure oil passage 74 through the choke valve 72. The oil that has flowed in is discharged through the opening 80. In this case, the oil pressure of the signal pressure oil passage 74 is determined by the flow characteristics of the choke-type throttle valve 72 and the flow rate characteristics of the opening 80, which is an orifice-type throttle valve. Chiyoke type throttle valve 72
The flow rate characteristic of The throttle valve whose flow characteristics are determined in relation to the flow rate is an orifice type throttle valve).

Q = A The flow rate passing through the choke-type throttle valve 72 is significantly reduced. Therefore, the oil pressure in the signal pressure oil passage 74 becomes extremely small. In this way, the lower the oil temperature, the lower the oil pressure in the signal pressure oil passage 74.
The hydraulic pressure acting on 6 becomes very small and the spool 32a is not switched against the force of the spring 32b. In addition, in this state, solenoid 3
6 is turned on and the opening 80 is closed, the oil pressure in the signal pressure oil passage 74 increases, but since the amount of oil supplied through the choke valve 72 is small, there is a slight delay in the increase in oil pressure. be. However, in general, the lock-up mechanism is controlled so as not to operate at a low temperature immediately after starting, so the solenoid 36 is not turned on when the oil temperature is low, and the solenoid 36 is not turned on when the oil temperature is low.
6 is turned on, the time when the oil temperature is low and there is a response delay when the oil pressure rises is not that long, so even if there is a delay in the oil pressure response, it will not actually be a problem. do not have.

On the other hand, when the temperature of the oil increases, the oil pressure in the signal pressure oil passage 74 increases, but this oil pressure is set to be lower than the switching pressure of the lock-up control valve 32. Therefore, even when the oil temperature reaches the normal operating temperature, the lock-up control valve 3 is activated even though the solenoid 36 is not turned on.
2 never switches to the lockup side. When the lock-up control solenoid 36 is turned on in this state, the oil has a small kinematic viscosity coefficient ν and a sufficient flow rate of oil is supplied to the signal pressure oil passage 74 through the choke-type throttle valve 72, so that the oil pressure in the signal pressure oil passage 74 is immediately rises to the same value as the oil pressure in the line hydraulic path 58. That is, the responsiveness of the oil pressure of the signal pressure oil passage 74 to the switching of the solenoid 36 to on is very good. Therefore, even if the choke valve 72 is used at a steady operating temperature, the same hydraulic responsiveness as in the prior art can be obtained.

In this embodiment, the present invention is applied to the case where the switching of the lock-up control valve 32 is controlled by the oil pressure of the signal pressure oil passage 74 controlled by the solenoid 36, but the present invention is applied to the lock-up control valve 32. It is obvious that the present invention can be applied to switching valves other than valves, and it goes without saying that the present invention can also be applied to the case where the duty of a signal pressure oil passage is controlled by a solenoid.

(G) Effects of the Invention As explained above, according to the present invention, since the throttle valve that branches the signal pressure oil path from the oil pressure source oil path is a choke-type throttle valve, the signal pressure oil path remains in the flow at low temperatures. It is possible to lower the pressure and operate valves, etc. controlled by the oil pressure in the signal pressure oil path as specified, and at normal operating temperatures, the response is the same as when using an orifice type throttle valve. You can get sex.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a hydraulic circuit including a hydraulic control device according to the present invention, and FIG. 2 is a skeleton diagram of an automatic transmission. 36...Solenoid, 58...Line pressure oil path (hydraulic source oil path), 72...Chiyoke type throttle valve, 74
...Signal pressure oil line.

Claims (1)

[Claims] 1. The signal pressure oil path is controlled by a solenoid to open and close an opening with an orifice type throttle valve provided in the signal pressure oil path connected to the oil pressure source oil path via the throttle valve. A hydraulic control device having a solenoid that controls hydraulic pressure, wherein the throttle valve between the hydraulic pressure source oil path and the signal pressure oil path is a chiyoke type throttle valve.