JPH02304245A - Signal pressure generation device - Google Patents

Abstract

PURPOSE:To prevent an outputted pressure level drop, a vibration, and the malfunction and improper operation of other systems controlled with outputted pressure by connecting the source pressure circuit of a reducing valve to the output circuit thereof with a bypass circuit fitted with a throttle element. CONSTITUTION:A source pressure circuit 29 is connected to an output circuit 27 with a bypass circuit 33 fitted with an orifice 32 as a throttle element. Furthermore, the bypass circuit 33 and the source pressure circuit 29 are connected to each other via the port groove 1e connected with the source pressure circuit 29 of a pilot valve 1. According to the aforesaid construction, a hydraulic fluid in the source pressure circuit 29 is directly supplied to the output circuit 27 at a ratio according to the inner diameter of the orifice 32. As a result, however, even when pilot pressure PP tries to rise, the level thereof is fed back to a chamber 1c, and the output circuit 27 is made open to a drain port 1d. Consequently, the pilot pressure PP does not rise and is maintained at an adjusted value. Also, the bypass circuit 33 does not hinder the pressure adjustment operation of the reducing valve 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a signal pressure generating device used in a hydraulic circuit of an automatic transmission or the like.

(Prior Art) This type of signal pressure generating device was developed by the applicant in 1987.
Among the automatic transmissions described in the "rREJROIA Type Automatic Transmission Maintenance Manual" (A261CO7) published in 2010, there is one that is used for stroke control of shift valves and overrun clutch control valves.

As shown in FIG. 2, this device is equipped with a pilot valve l,
As a result, the line pressure P is reduced to a constant pilot pressure P, and the orifice 3. 5. 7 and head to the signal pressure circuit skin 11.13. The circuit 9°11.13 has a drain port (15.17.19) in the middle, and a normally closed solenoid valve 21.23.25 is installed opposite to this.

When the solenoid valves 21, 23, and 25 are respectively OFF, drain port) 15.17.19 Close the circuit skin 11.13
Signal pressure PSI of the same value as pilot pressure Pp from P
S2. PS3 is generated and output. solenoid valve 2
1.23.25 when ON, corresponding drain port) 15
．． 17.19 is opened to eliminate the signal pressure from circuit 9.11,13. During this time, orifice 3. 5. 7
Therefore, the pilot pressure Pp can maintain the pressure regulated value by the pilot valve 1.

(Problem to be Solved by the Invention) However, in such a conventional signal pressure generating device, especially when there are a plurality of solenoid valves, when all of these solenoid valves are opened, the instant t in FIG.

As will be seen hereafter, the large total drain amount from 15.17.19 caused the pilot valve 1 to increase the pilot pressure P.
, it becomes impossible to maintain the pressure regulation value shown by the solid line in Figure 3, and the level of pilot pressure becomes insufficient as shown by the dotted line in the figure, or other systems that vibrate this pilot pressure and control with the same pilot pressure. have a negative impact on

The reason why the above-mentioned vibration occurs is that when the pilot valve 1 is unable to maintain the pilot pressure Pp at the regulated pressure value as described above, the pilot valve 1 becomes regulated when the opening degree shown by α in Fig. 2 is extremely large. This is because the pressure action is being attempted and this action is unstable.

An object of the present invention is to solve the above-mentioned problem by bypassing the pilot valve (pressure reducing valve) and replenishing the working fluid.

(Means for Solving the Problem) For this purpose, the present invention reduces the source pressure from the source pressure circuit using a pressure reducing valve and outputs it to the output circuit, and when this output pressure is drained downstream of the throttle element, a signal is sent. In the signal pressure generation device, the signal pressure is generated by dissipating the pressure and stopping the drain, the source pressure circuit and the output circuit being connected by a bypass circuit in which a throttle element is inserted. be.

(Function) The pressure reducing valve reduces the source pressure from the source pressure circuit and outputs it to the output circuit, and this output pressure is transmitted downstream through the throttle element. Thus, when draining, the downstream side of the throttle element is left in an unpressurized state, and no signal pressure is generated downstream. When the drain is stopped, a signal pressure having the same value as the output pressure is generated downstream of the throttle element.

By the way, since the source pressure circuit and the output circuit are connected by a bypass circuit in which a throttling element is inserted, there is a situation in which the above-mentioned drain is so large that the pressure reducing valve would normally be unable to maintain the output pressure at the pressure regulation value. However, the excess amount of drain can be compensated for by the additional flow from the bypass circuit, and the pressure reducing valve maintains the output pressure at the regulated value with a stable pressure regulating action, which prevents insufficient output pressure level and vibration. It can be prevented.

Therefore, the operation of other control systems that are directly or indirectly controlled by this output pressure can be prevented from malfunctioning or becoming inaccurate.

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

Figure 1 shows an embodiment of the signal pressure generating device of the present invention.
Similar parts in the figure are designated by the same reference numerals.

The pilot valve l as a pressure reducing valve is provided with a spool 1a,
This is biased to the right in the figure by a spring 1b. The spool 1a is in the right-hand position in the figure, and the output circuit 27 is connected to the source pressure circuit 29.
Line pressure PL as a source pressure is supplied to this source pressure circuit. At the right-hand position of the spool 1a in the figure, the line pressure PL of the circuit 29 generates a pyropressure P in the output circuit 27, and this pilot pressure is passed through the feedback circuit 31 to the chamber 1c.
, the spool la is pushed back to the left in the figure against the spring tb. The pushback amount increases as the pilot pressure P increases, and when the pilot pressure P exceeds the value corresponding to the spring force of the spring 1b, the spool 1a cuts off the output circuit 27 from the source pressure circuit 29, and drains the drain bow) 1d. Switch the connection to drain the excess pilot pressure. Thus, the pilot valve 1 outputs pilot pressure P to the output circuit 27.
P is maintained at a constant pressure adjustment value corresponding to the spring force of spring lb as shown by the solid line in FIG.

In order to achieve the above-mentioned object of the present invention, the source pressure circuit 29
and the output circuit 27 through the orifice 3 as a diaphragm element.
2 is connected by a bypass circuit 33 in which a circuit 2 is inserted. In this example, the bypass circuit 33 and the source pressure circuit 29 are connected via the input port groove 1e to which the source pressure circuit 29 of the pilot valve 1 is connected.

As a result, the working fluid in the source pressure circuit 29 is always directly supplied to the output circuit 27 at a rate corresponding to the inner diameter of the orifice 32. However, even if the pilot pressure P is about to rise due to this, this is fed back to the chamber 1c and the output circuit 27 is connected to the drain port 1d, so the pilot pressure P is not increased and is kept at the regulated pressure value. The bypass circuit 33 does not interfere with the pressure regulating action of the pressure reducing valve 1.

The output circuit 27 is branched by the number of valves to be controlled by the signal pressure (three in the illustrated example); 1. An orifice as a throttle element is provided in each branch path; 3. 5. 7 are inserted, and the signal pressure circuit 9°11, 13 is formed downstream of these orifices.

Each signal pressure circuit has a valve (not shown) that should be controlled by signal pressure.
and a drain boat 15.17.19 will be installed on the way. Drain port) 15.17.19 is provided with a first solenoid valve 21, a second solenoid valve 23, and a third solenoid valve 25, respectively, and these valves are normally connected to the spring 21a.
, 23a, 25a urge the valve bodies 21b, 23b, 25b in the valve closing direction to drain the drain boat 15.17.
．． 19 is closed, and when the solenoids 21C, 23c, and 25c are turned on, the corresponding drain boat is opened.

The operation of the above embodiment will be explained next.

The pilot valve 1 lowers the line pressure P of the circuit 29 by the above action.
p is reduced to a constant pilot pressure Pp, circuit 27
It is output to. The first solenoid valve 21 is connected to the solenoid 2
When the IC is closed by turning OFF, a signal pressure PSI having the same value as the pilot pressure Pp is output from the circuit 9, and the solenoid valve 2
1 is opened by turning on the solenoid 21C (and the signal pressure Ps
i is drained by the drain boat 15 and disappears, and the stroke of the corresponding valve can be controlled by the signal pressure PSI. Similarly, turn on solenoid valves 23 and 25,
Signal pressure PS 21 P from circuit 11.13 when OFF
By the way, the source pressure circuit 29 can eliminate or generate s3 and control the stroke of the corresponding valve.
A bypass circuit 33 connecting between the output circuit 27 and the output circuit 27 allows the working fluid flow of the source pressure circuit 290 to directly flow into the output circuit 27 at a rate according to the inner diameter of the orifice 32. For this reason, all solenoid valves 21, 23, 25 are opened (po) 1
5. The total amount of drain from 17.19 has increased, and even though the pilot valve l would normally be unable to maintain the above pressure regulation value, the amount of drain that flows from the bypass circuit 33 has increased. You can make up for it. Therefore,
In this case as well, the pilot valve 1 can continue the pressure regulation action, and the pilot pressure Pp reaches the pressure regulation value as shown by the solid line in the figure without reducing the level or vibrating as shown by the dotted line in the figure. can be maintained. Therefore, the operations of other control systems that are directly or indirectly controlled by the pilot pressure P can be prevented from malfunctioning or becoming inaccurate.

(Effects of the Invention) Thus, as described above, the signal pressure generating device of the present invention includes a bypass circuit in which a throttling element (32) is inserted between the source pressure circuit (29) and the output circuit (27) of the pressure reducing valve (1). (33), this bypass circuit additionally supplies working fluid from the source pressure circuit to the output circuit, so even if the drain amount in the signal pressure circuit (9, 11, 13) increases, the pressure reducing valve It is possible to continue stable pressure regulation, and the output pressure (P
P) can be prevented from decreasing in level or vibrating, and the operation of other systems controlled by this output pressure can be prevented from malfunctioning or becoming inaccurate.

[Brief explanation of drawings]

Fig. 1 is a hydraulic circuit diagram showing an embodiment of the signal pressure generating device of the present invention, Fig. 2 is a hydraulic circuit diagram showing a conventional signal pressure generating device, and Fig. 3 is the pilot pressure when all solenoid valves are open. It is a time chart showing a comparison of changes between the case using the device of the present invention and the case using the conventional device. 1... Pilot valve (pressure reducing valve) 3, 5.7... Orifice (throttling element) 9, 21.1
3... Signal pressure circuit 15, 17.19... Drain boat 21, 23.25... Solenoid valve 27... Output circuit 29... Source pressure circuit 32
...Orifice (aperture element) 33...Bypass circuit. Figure 1 Figure 2

Claims (1)

[Claims] 1. The source pressure from the source pressure circuit is reduced by a pressure reducing valve and outputted to the output circuit, and when this output pressure is drained downstream of the throttle element, the signal pressure disappears, and when the drain is stopped, the signal pressure is generated. A signal pressure generating device characterized in that the source pressure circuit and the output circuit are connected by a bypass circuit in which a throttle element is inserted.