JPH0717841Y2 - Switching valve for regeneration - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a regeneration switching valve that allows return oil from the sixth-degree chamber of a cylinder to join the bottom-side chamber of the cylinder as needed.

<Prior Art> Conventionally, a switching valve of this type is shown in FIG. 3 (Japanese Patent Laid-Open No. 62-278).
No. 302).

This switching valve is connected to the fitting hole 1a of the valve body 1, the bridge passage 2 connected to the hydraulic power source P, the first load passage 3 connected to the bottom side chamber 6a of the cylinder 6, and the rod side chamber 6b of the cylinder 6. The second load passage 4 and the discharge passage 5 connected to the tank T are opened, and the spool 7 is slidably fitted in the fitting hole 1a. The spool 7 has a first side on one side.
An annular groove 8 for switching and connecting the load passage 3 to either the bridge passage 2 or the discharge passage 5 is provided, and an oil chamber 10 communicating with the discharge passage 5 through a throttle hole 9 therein, and an oil chamber 10
A valve hole (12) connected to the valve seat (11) via a valve seat (11) is provided.
The oil chamber 10 has a first through hole 13 communicating with the first load passage 4.
And a second through hole 14 communicating with the bridge passage 2 when the spool 7 moves rightward in the drawing. In the valve hole 12, a poppet valve 16 which is pressed against the valve seat 11 by a spring 15 is slidably installed. Form a closed pressure receiving chamber 18 behind
The first load passage 3 is communicated with the pressure receiving chamber 18 via an oil passage hole 19.

This switching valve for regeneration starts from the neutral position shown in FIG.
Is moved rightward, the bridge passage 2 and the first load passage 3 are communicated with each other by the annular groove 8, the pressure oil from the hydraulic pressure source P is supplied to the bottom side chamber 6a of the cylinder 6, and the return oil from the rod side chamber 6b is supplied. Is discharged from the discharge passage 5 to the tank T through the second load passage 4, the first through hole 13, the oil chamber 10 and the throttle through hole 9. In this state, if a load acts on the cylinder 6 in the direction of the arrow W, the pressure in the bottom side chamber 6a decreases, and the pressure in the pressure receiving chamber 18 communicating with the first load passage 3 via the oil passage hole 19 increases. descend. The pressure in the pressure receiving chamber 18 is reduced by the throttle through hole 9
When the pressure drops below the pressure of the oil chamber 10 which is boosted by the poppet valve 16, the poppet valve 16 overcomes the force of the spring 15 and separates from the valve seat 11.
The first through hole 13 and the second through hole 14 are communicated with each other, the second load passage 4 and the bridge passage 2 are communicated with each other, and the return oil from the rod side chamber 6b of the cylinder 6 is passed through the bridge passage 2 and the cylinder 6
It joins the bottom side chamber 6a.

<Problems to be Solved by the Invention> In the conventional regeneration switching valve described above, the bottom side chamber 6a of the cylinder 6 is inserted into the pressure receiving chamber 18 behind the poppet valve 16 through the oil passage hole 19.
The pressure of the pressure receiving chamber 18 is detected to open and close the poppet valve 14, and the oil passage hole 19 communicates with the first load passage 3 at the neutral position in FIG. Has become. However, the valve hole 12 that houses the poppet valve 16 is
Since the spool 7 is machined from the end thereof, the cylindricity thereof is inaccurate and a gap is formed between the spool 7 and the poppet valve 16. Therefore, the bottom side chamber 6a is affected by the load acting on the cylinder 6.
Pressure oil flows into the pressure receiving chamber 18 through the oil passage hole 19, and
There is a risk of leakage from 18 through the periphery of the poppet valve 16, and there is a problem that the cylinder 6 cannot be reliably held in the neutral position. Further, since the opening of the valve hole 12 that opens at the end of the spool 7 is closed by the plug plug 17 and the pressure receiving chamber 18 is provided behind the poppet valve 16, the valve hole
The annular groove 8 must be provided in the thickness of the spool 7 less the inner diameter of 12, and the processing of the annular groove 8 is limited. There was also a problem that the area could not be obtained.

<Means for Solving the Problems> The regeneration switching valve of the present invention includes a spool slidably fitted in a fitting hole of a valve body, one of a bridge passage connected to a hydraulic pressure source, and a bottom chamber of a cylinder. An annular groove communicating with the first load passage to be connected is provided, and in this spool, a second load passage connected to the rod side chamber of the cylinder is communicated via the first through hole, and an exhaust passage connected to the tank is provided. An oil chamber communicating with the throttle passage and a valve hole communicating with the other of the bridge passages via the second passage are provided, and in the valve hole,
A poppet valve that is pressed by a spring is installed inside a valve seat provided between the oil chamber and the valve hole, and behind this poppet valve,
In a regeneration switching valve having a pressure receiving chamber communicating with the first load passage via an oil passage hole, the oil passage hole is opened on a peripheral surface of the spool, and the opening portion of the valve main body is at a neutral position of the spool. The spool is closed by a fitting hole, and the spool is divided into a first spool having a valve hole for accommodating a spring and a poppet valve and a second spool having an annular groove. The second spool is screwed to form the pressure receiving chamber in the first spool.

<Operation> According to this means, since the oil passage hole for guiding the pressure in the first load passage to the pressure receiving chamber behind the poppet valve is closed by the fitting hole in the valve body at the neutral position, the pressure oil in the bottom chamber of the cylinder is closed. Does not flow into the pressure receiving chamber through the oil passage and does not leak from the pressure receiving chamber through the periphery of the poppet valve. Further, the spool is divided into a first spool having a valve hole for accommodating a spring and a poppet valve and a second spool having an annular groove. The second spool is screwed onto the first spool. Since the pressure receiving chamber is formed in the first spool, the spool can be provided with the annular groove regardless of the valve hole in which the poppet valve is installed, and the processing of the annular groove is not limited. .

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings. In the description, only the parts different from the prior art (FIG. 3) will be described, and the same components will be denoted by the same reference numerals and the description thereof will be omitted.

1 is different from FIG. 3 in that the spool 7
Firstly provided with a valve hole 12 for accommodating a spring 15 and a poppet valve 16
The spool 7a and the second spool 7b having the annular groove 8 are connected to each other, and the first spool 7a has a second spool.
7b is fixed by a screw portion 20 and is sealed by a seal member 21 such as an O-ring to form a pressure receiving chamber 18 behind the poppet valve 16 in the first spool 7a. Further, the second spool 7b is provided with an oil passage hole 19 communicating with the pressure receiving chamber 18, and the oil passage hole 19 is provided on the spool peripheral surface which is a sliding surface of the spool 7b with respect to the fitting hole 1a. It is open. The opening 19a is closed by the valve body 1 at the neutral position in FIG. 1 and is cut off from the first load passage 3. In the neutral position of FIG. 1, the first through hole 13 communicates with the bridge passage 2 and the throttle through hole 9
Is closed by the valve body 1 and has a connection relationship different from the conventional one, but this connection relationship may be the same as the conventional one.

In the above configuration, the oil passage hole 19 is in the neutral position in FIG.
The opening 19a is opened in the peripheral surface of the second spool 7b closed by the fitting hole 1a of the valve body 1, and is cut off from the first load passage 3. Therefore, the pressure oil in the bottom side chamber 6a of the cylinder 6 does not flow into the pressure receiving chamber 18 through the oil passage hole 19 due to the load acting on the cylinder 6, and the cylinder 6 may be inadvertently moved due to pressure oil leakage. Can be prevented. Next, when the spool 7 is moved rightward to the switching position shown in FIG. 2, the opening 19 of the oil passage hole 19 is opened.
a is removed from the fitting hole 1a of the valve body 1 and communicates with the first load passage 3. Therefore, when the pressure in the bottom side chamber 6a of the cylinder 6 is introduced into the pressure receiving chamber 18 through the oil passage hole 19 and a load acts on the cylinder 6 in the direction of the arrow W, the pressure in the pressure receiving chamber 18 decreases. The pressure in the oil chamber 10 raised by the throttle passage hole 19 becomes lower, and the poppet valve 16 is separated from the valve seat 11 so that the first passage hole 13 and the second passage hole 14 communicate with each other, and The return oil from the rod side chamber 6b merges with the bottom side chamber 6a of the cylinder 6 from the second load passage 4 through the bridge passage 2. At this time, the pressure oil that has merged in the bridge passage 2 is supplied through the annular groove 8 of the spool 7.
Is processed into the second spool 7b that is screwed into the first spool 7a, and therefore has an opening area that allows the entire amount of pressure oil obtained by combining the return oil from the rod side chamber 6b of the cylinder 6 to flow. Therefore, there is no resistance in supplying to the bottom side chamber 6a of the cylinder 6, and the return oil from the rod side chamber 6b can be efficiently merged with the bottom side chamber 6a of the cylinder 6.

<Effects of Device> As is apparent from the above description, according to the regeneration switching valve of the present invention, the oil passage that guides the pressure in the first load passage to the pressure receiving chamber behind the poppet valve is provided at the neutral position. Since it is configured to be closed by the fitting hole of the main body, the pressure oil in the bottom chamber of the cylinder does not flow into the pressure receiving chamber via the oil passage hole.
Therefore, it is possible to prevent an inadvertent movement of the cylinder due to leakage of pressure oil, and it is possible to allow a margin for the processing accuracy of the valve hole in the spool.

Further, the spool has a structure in which the second spool having an annular groove formed in the opening of the valve hole of the first spool is screwed to form the pressure receiving chamber in the first spool. Without being limited by the above, an opening area for merging all the return oil from the rod side chamber of the cylinder can be obtained, and efficient merging can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing the neutral position of an embodiment of the present invention, FIG. 2 is a sectional view showing the switching position of the embodiment, and FIG. 3 is an example of a conventional regeneration switching valve. FIG. 1 ... Valve body, 1a ... Fitting hole, 2 ... Bridge passage, 3
...... First load passage, 4 ... Second load passage, 5 ... Discharge passage, 7 ... Spool, 7a ... First spool, 7b ... Second
Spool, 8 ... annular groove, 9 ... throttle through hole, 10 ... oil chamber, 11 ... valve seat, 12 ... valve hole, 13 ... first through hole, 14 ...
2nd through hole, 15 ...... spring, 16 ... poppet valve, 18 ... pressure receiving chamber, 19 ... oil hole.

Claims (2)

[Scope of utility model registration request] 1. A spool, which is slidably fitted in a fitting hole of a valve body, is provided with an annular groove for communicating one of a bridge passage connected to a hydraulic pressure source and a first load passage connected to a bottom side chamber of a cylinder. In the spool, the second load passage connected to the rod side chamber of the cylinder is communicated with the second load passage through the first through hole.
An oil chamber communicating with the discharge passage connected to the tank via the throttle passage and a valve hole communicating with the other one of the bridge passages via the second passage are provided in the valve passage. A valve seat provided between the valve seat and the valve hole is internally provided with a poppet valve that is pressed by a spring, and a pressure receiving chamber that communicates with the first load passage through an oil passage hole is provided behind the poppet valve. A switching valve for regeneration, characterized in that the oil passage hole is opened on the circumferential surface of the spool, and the opening portion is closed by a fitting hole of the valve body at a neutral position of the spool. 2. A spool, which is slidably fitted in a fitting hole of a valve body, has an annular groove for communicating one of a bridge passage connected to a hydraulic power source and a first load passage connected to a bottom side chamber of a cylinder. In the spool, the second load passage connected to the rod side chamber of the cylinder is communicated with the second load passage through the first through hole.
An oil chamber communicating with the discharge passage connected to the tank via the throttle passage and a valve hole communicating with the other one of the bridge passages via the second passage are provided in the valve passage. A valve seat provided between the valve seat and the valve hole is internally provided with a poppet valve that is pressed by a spring, and a pressure receiving chamber that communicates with the first load passage through an oil passage hole is provided behind the poppet valve. In the switching valve for a vehicle, the spool is divided into a first spool having a valve hole that internally houses a spring and a poppet valve, and a second spool having an annular groove, and the second spool is screwed to the first spool. And the pressure receiving chamber is formed in the first spool.