JPH08184301A - Hydraulic control device - Google Patents

Abstract

PURPOSE: To provide a hydraulic control device in which pressure loss and leakage are little and assembly is easy, and not only a fixed throttle but also a variable one can therefore be simply set up, and priority pressure can be voluntarily obtained. CONSTITUTION: A hydraulic control device has a pair of actuator ports 2, 3 formed in a main body housing 31; a tandem passage 5; a parallel passage 6; the first and the second communicating passages 7, 8; a main spool 4 slidably provided in the main body housing; and a tandem check part 20 which is directly communicated with the tandem passage 5 and composed of the first poppet 10 to allow only communication from the tandem passage to the first communicating passage, and is moreover equipped with a parallel check part 21 composed of the second poppet 11 to allow only communication from the parallel passage to the second communicating passage; a passage to mutually communicate both the check parts provided on the backs of both the poppets; and a throttle 19 formed in the above passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system having a tandem passage and a parallel passage and using a plurality of actuators for one pump.

[0002]

2. Description of the Related Art The conventional hydraulic control device shown in FIGS. 4 and 5 has already been proposed by the applicant as a device disclosed in Japanese Patent Publication No. 6-12121. In this conventional device, a body housing 31 has a pair of actuator ports 32,
33 is formed, and a spool 34 is slidably provided on the valve body. The tandem passage 35 is opened when the spool 34 is held at the neutral position, and the tandem passage 35 is closed when the spool 34 is switched. The valve structure of the main body housing located upstream of the main body housing 31 shown in the drawing also opens the tandem passage when the spool is in the neutral position and closes it when it is switched. Therefore, the tandem passages are in communication with each other through the tandem passages when all the spools of the valve arrangements of the main body housings are kept in the neutral position.

In the body housing 31 shown in the figure,
A sleeve 39 is provided which directly communicates with the tandem passage 35, and a parallel passage 36 is formed at a predetermined position around the sleeve 39. Further, a communication passage 37 that communicates with one actuator port 32 and a communication passage 38 that communicates with the other actuator port 33 are formed according to the moving position of the spool. The parallel passage 3
6 and the tandem passage 35 are separated by a sleeve 39. Then, the first poppet 4 is attached to the sleeve 39.
0 and the second poppet 41 are fitted together. Further, a fixed aperture 42 is provided in a fitting gap between the sleeve 39 and the main body housing 31.

In the above hydraulic control device, when the spool 34 is switched in the direction of arrow A while the upstream side valve mechanism (not shown) is kept in the neutral position, the discharge oil of the pump is discharged from the neutral passage. Tandem passage 3 via 46
Guided by 5. The pressure oil thus guided to the tandem passage 35 pushes up the first poppet 40, and the second communication passage 3
8 through notch 43, actuator port 3
Outflow to 3. When the valve mechanism on the upstream side is switched from the above state, the pressure oil is not supplied to the neutral passage 46. However, in this case, since the pressure oil is supplied to the parallel passage 36, the pressure oil is supplied to the first or second communication passage 37, 38 via the fixed throttle 42.

In any case, when the pressure oil is supplied from the neutral passage 46, since all the valve mechanisms are connected in tandem, it is impossible to simultaneously operate a plurality of actuators. Therefore, in this case, the tandem passage 35 is directly connected to the first or second communication passage 3
Pressure oil is supplied to 7 or 38. However,
When the valve mechanisms are connected in parallel, the pressure oil is preferentially supplied to the light load actuator. Therefore, in this case, in the illustrated valve mechanism, a fixed orifice 42 is provided in the course of passage through the parallel passage 36 to maintain a circuit pressure above a certain pressure, and the light load actuator connected to this valve mechanism has priority. To prevent pressure oil from being supplied.

[0006]

In the above-mentioned conventional device,
Since the first poppet 40 for tandem load check and the second poppet 41 for parallel load check are fitted to the sleeve 39, a large passage area can be secured due to the sleeve 39 in the passage. However, there was a problem that the pressure loss was large. In addition, there is a problem that oil leaks from the fitting gap between the second poppet 41 and the sleeve 39, the leak amount is large, the structure is complicated, and the assembling property is poor. In addition, there are space restrictions, and parallel passage 3
As a means for generating the preferential pressure at 6, only the fixed throttle 42 can be provided on the sleeve 39. Therefore,
It is an object of the present invention to provide a structure that has less pressure loss and less leakage and is easy to assemble. Further, not only the fixed throttle but also the variable throttle can be easily set so that the priority pressure can be arbitrarily obtained.

[0007]

According to a first aspect of the present invention, a pair of actuator ports formed in a main body housing, a tandem passage, a parallel passage, a pair of communication passages are provided slidably in the main body housing. A main spool, a tandem check unit that directly communicates with the tandem passage and allows only communication from the tandem passage to the first or second communicating passage, and a parallel that allows only communication from the parallel passage to the first or second communicating passage. The hydraulic control device includes a check portion, a passage formed on the back surface of both check portions, which connects the check portions to each other, and a throttle formed in the passage. Second
According to the invention of claim 1, a sub-spool operated by pilot pressure from the outside is installed in a passage communicating with both check parts formed on the back surface of both check parts of the above invention, and a notch formed in the sub-spool is variable throttled. It is characterized by that. A third aspect of the invention is characterized in that a restrictor valve for reducing pressure by an orifice is installed in a pilot passage for introducing pilot pressure.

[0008]

In the first invention, the tandem check unit and the parallel check unit are separately provided, and both check units are
It communicates with the passage formed in the back. When the main spool moves and the oil from the parallel passage passes through the passage and flows to one actuator port, priority pressure is generated in the parallel passage due to the throttle in the passage. As in the second aspect of the invention, when the variable throttle formed of the notched sub-spool that is operated by the external pilot pressure is formed in the passage at the back of both check parts,
The throttle opening changes according to the pilot pressure. The priority pressure can be arbitrarily controlled by the change in the throttle opening. Since the throttle is provided as in the third aspect of the invention, the response delay of the sub spool can be caused, and the shock at the time of starting the actuator can be alleviated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment shown in FIG.
A pair of actuator ports 2 and 3 formed in 1;
A tandem passage 5, a parallel passage 6, and a pair of communication passages 7 and 8 are formed. The main spool 4 slidably provided in the main body housing 31 and the tandem passage 5 are directly communicated with each other from the tandem passage to the first or second tandem passage.
A tandem check unit 20 that allows only communication to the communication passages 7 and 8, and a parallel check unit 2 that allows only communication from the parallel passage 6 to the first or second communication passages 7 and 8.
1 and are provided. In the sub-housing 1 provided on the back surface of both the check parts 20 and 21, both the check parts 20 and
A passage 22 communicating with the passage 21 and a pair of fixed throttles 19 communicating with the passage 22 are provided. The tandem check unit 20 includes a first poppet 10, a first spring 14, and a poppet passage 25. Further, the parallel check portion 21 includes the second poppet 11, the second spring, and the poppet internal passage 26.

If the main spool 4 is switched in the direction of arrow A while the upstream valve mechanism is kept in the neutral position, the oil supplied to the neutral passage 16 will pass through the tandem passage 5 and pass through the first poppet. Push it up, first communication passage 7 →
It flows out from the notch 13 provided on the main spool 4 to the actuator port 2. On the other hand, if the main spool 4 is switched in the direction of arrow A as described above while the upstream valve mechanism is switched, the oil supplied to the parallel passage 6 pushes up the second poppet 11 and Passage 26 → Fixed throttle 19 → Sub-housing passage 2
2 → fixed throttle 19 → first poppet passage 25 → first communication passage 7 → notch 13 provided in the main spool 4 → actuator port 2 By passing through the fixed throttle 19 in this channel,
Priority pressure will be generated. Therefore, the pressure oil is also supplied to the other heavy load actuators connected in parallel.

In the second embodiment shown in FIG. 2, a pilot port 17 for applying a pilot pressure from the outside is formed in the sub-housing 1, a sub-spool 9 operated by this pilot pressure and a third spring for supporting the sub-spool 9. 18 and. An annular groove 9a is formed on the sub-spool 9, and a notch 12 continuous with the annular groove 9a is formed. Therefore, by moving the spool 9 against the spring 18, the opening of the variable throttle formed between the notch 12 and the port 1a of the sub-housing 1 is controlled. Further, the end of the spool 9 on the side opposite to the spring 18 faces the pilot chamber 23, which is connected to the pilot pump PP and the drain port 24 via the restriction valve R. ing.

The restrictor valve R has a fixed orifice 28 formed in its poppet 27, and the poppet 27 is acted by a spring 28 so that the seat portion 2 is actuated.
It is configured to be pressed against 9. Also, the poppet 27
The back pressure chamber 30 is connected to the drain port 24. The drain port 24 communicates with the tank T when the main spool 4 is in the neutral position shown in the drawing, and when the main spool 4 moves in the direction of the arrow A, the tank The communication with T is cut off. Therefore, when the main spool 4 is switched in the direction of arrow A, the pressure oil of the pilot pump PP is guided to the pilot chamber 23 through the fixed orifice 28 of the restriction valve R. When the pressure oil is introduced into the pilot chamber 23, the sub spool 9 moves against the spring 18 and controls the opening of the variable throttle including the notch 12.

In the above state, while switching the valve mechanism on the upstream side and moving the main spool 4 of the illustrated valve mechanism in the direction of arrow A, the pressure oil supplied to the parallel passage 6 causes the parallel check portion 21 to move. It is pushed open and once comes out to the second communication passage 8, and then passes through the second in-poppet passage 26 and the variable throttle. Then, the pressure oil that has passed through the variable throttle passes through the second poppet internal passage 25 and flows out from the first communication passage 7 to the actuator port. Although the priority pressure is generated in the parallel passage 6 by the passage of the fluid through the variable throttle, the priority pressure also changes as the throttle opening changes. The reason why the restrictor valve R is provided as described above to delay its responsiveness is
This is to reduce the shock of the actuator.

Further, the sub spool 9 is the main spool 4
If it operates sensitively to the movement of the notch 12, the notch 12 forming the variable diaphragm must be made minute. However, although there is a limit to that, there is an advantage that the notch 12 does not need to be made very small by reducing the response as in this embodiment. In addition, when the upstream valve mechanism is not switched, the oil supplied to the neutral passage 16 causes the tandem passage 5 (by pushing up the first poppet).
-> First communication passage 7-> Actuator port 2 flows out. In the third embodiment shown in FIG. 3, the sub housing and the main body housing 31 are integrated, and the main body housing 31 is provided with the passage 2.
2 is the same as that of the first embodiment except that the fixed throttle 19 is formed on the plug, and its operation is also the same.

[0015]

According to the present invention, unlike the conventional example, since the housing and the sleeve and the sleeve and the poppet are not fitted to each other, the number of oil leaks is reduced and the leak amount is reduced. Further, since the flow path obstruction by the sleeve is eliminated, the pressure loss is reduced, and the structure is simplified, so that the assemblability and workability are improved. By placing the tandem check section and the parallel check section separately, the degree of freedom of the form and installation position of the throttle is increased, and the throttle can also be a variable throttle. Can be controlled arbitrarily.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a third embodiment.

FIG. 4 is a sectional view of a conventional example.

FIG. 5 is a partially enlarged view of FIG.

[Explanation of symbols]

 31 Main body housing 1 Sub housing 2, 3 Actuator port 4 Main spool 5 Tandem passage 6 Parallel passage 7 First communicating passage 8 Second communicating passage 9 Sub spool 10 First poppet 11 Second poppet 12 Notch 19 Fixed throttle 20 Tandem check section 21 Parallel Check Section 22 Passage

Claims (3)

[Claims] 1. A pair of actuator ports formed in a main body housing, a tandem passage, and a parallel passage,
From the first and second communication passages, the main spool slidably provided in the main body housing, and the first poppet for directly communicating with the tandem passage and allowing only the communication from the tandem passage to the first communication passage. Tandem check part and second that allows only the communication from the parallel passage to the second communication passage
A hydraulic control device comprising: a parallel check part made of poppets; a passage communicating with both check parts provided on the backs of both poppets; and a throttle formed in the passage. 2. A sub-spool that operates by pilot pressure from the outside is installed in a passage that connects the tandem check section and the back section of the parallel check section, and the notch formed in the sub-spool is a variable throttle. The hydraulic control device described in. 3. The hydraulic control device according to claim 2, wherein a restrictor valve for reducing the pressure by an orifice is installed in the pilot passage for introducing the pilot pressure.