JP2813997B2 - Spool valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a spool valve, and more particularly, to a spool valve capable of shortening a stroke of a spool, thereby achieving a compact apparatus.

(Prior Art) An apparatus using a spool valve is disclosed in, for example,
There is one shown in JP-A-51-51682. This will be described with reference to FIG.

First, there is a fluid pump 101, and pressure oil supplied from the fluid pump 101 is supplied to a flow direction control valve 105 via a main circuit 103, and is supplied to an actuator 107 therefrom.

At this time, the pressure on the load side is fed back to the pressure control valve 111 via the feedback circuit 109. or,
A part of the pressure oil discharged from the fluid pump 101 is returned to a discharge amount variable control unit 115 via a pressure control valve 111 via a branch circuit 113 branched from the main circuit 103.

Then, by adjusting the return amount to the discharge amount variable control unit 115 according to the load pressure fed back, the discharge amount from the fluid pump 101 is appropriately maintained.

(Problem to be Solved by the Invention) According to the above-described conventional configuration, there is a problem that the flow direction control valve 105 becomes large.

To explain this in detail, the flow direction control valve 105 includes:
A spool 117 is slidably disposed. Then, for example, when the spool 117 is slid rightward in the drawing to supply the pressure oil to the actuator 107 via the circuit 119, first, the hole 121 of the feedback circuit 109 communicates with the load side.

When the spool 117 slides further to the right in the drawing, the variable flow control orifice 123 is in communication with the pump port 125.

That is, as the spool 117, in order to supply the pressure oil to the actuator 107, a stroke necessary for opening the hole 121 and a stroke necessary for opening the flow rate adjustment variable orifice 123 are added. Must slide for the stroke.

Since the stroke of the spool 117 is large, the flow direction control valve 105 itself becomes large.

The present invention has been made based on such a point, and an object of the present invention is to provide a spool valve capable of making the entire apparatus compact by shortening the stroke of the spool.

(Means for Solving the Problems) In order to achieve the above object, a spool valve according to the present invention comprises a housing provided with a pump port, a load port, and a load pressure detecting circuit, and an end thereof slidably housed in the housing. A portion of the spool protruding from the housing, a cap fixed to the housing so as to cover the portion of the spool protruding from the housing, and a load port formed on the spool and sliding with the load to communicate with the load pressure detection circuit. A timing notch to be formed, and a substantially same axial position formed on the spool as the timing notch and at a position different in the circumferential direction and substantially the same timing as the communication between the timing notch and the load pressure detecting circuit by sliding of the spool. And a metering notch that connects the load port and the pump port with And a fitting structure for restricting rotation of the spool by a fitting shape with respect to the end of the spool.

(Operation) First, in the case of the spool valve according to the present invention, the rotation of the spool is restricted by the fitting structure, and therefore, even if the spool slides, its circumferential position does not fluctuate. Absent.

A timing notch and a metering notch are formed at substantially the same position in the axial direction of the spool but at different positions in the circumferential direction.

Then, when the spool slides, the load port and the load pressure detection circuit are communicated through the timing notch, and the load pressure is fed back. Also, at substantially the same timing, through the metering notch,
The load port and the pump port communicate with each other, and the pressure oil is supplied to the load side.

In other words, the feedback and the supply of pressure oil to the load side
It will be performed at about the same timing, and that much,
A small stroke of the spool will suffice. Thereby, the size of the entire apparatus is reduced.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. 1 and FIG. FIG. 1 is a sectional view of a spool valve according to the present embodiment, and FIG. 2 is a sectional view taken along line II-II of FIG.

A spool 3 is accommodated in the housing 1 so as to be slidable in the left-right direction in the figure. Both ends of the spool 3 protrude from the housing 1, and caps 5 and 7 are fixed to the housing 1 so as to cover the protruding ends.

In the cap 5, a compression coil spring 9 is provided.
The compression coil spring 9 accommodates the spool 3 in a state held by a pair of support members 11 and 13.
Is held in the neutral position.

The configuration inside the cap 7 will be described later in detail.

A pump port 15 is formed substantially at the center of the housing 1 in the left-right direction in the drawing, and load ports 17 and 19 communicating with an actuator (not shown) are formed on both sides of the pump port 15. I have. Tank ports 21 and 23 communicating with a tank (not shown) are formed on both sides of the load ports 17 and 19, respectively.

The housing 1 is provided with load pressure detection circuits 20 and 22 for feeding back the load pressure.

On the other hand, the spool 3 is provided with reduced diameter portions 25 and 27 at positions corresponding to the load ports 17 and 19, respectively. On the pump port 15 side of the reduced diameter portion 25, at a position of 180 °,
A pair of metering notches 29, 29 are formed (only one is shown in the figure).

Further, a pair of timing notches 31, 31 are formed at substantially the same position in the axial direction and orthogonal to the pair of metering notches 29, 29.

The same configuration is also applied to the reduced diameter portion 27 side,
In the drawings, the same portions are denoted by the same reference numerals, and description thereof will be omitted.

A passage 33 is formed on the reduced diameter portion 25 side of the spool 1, and passages 35 and 37 are formed to communicate the passage 33 with the above-described tank port 21. this is,
This is to release the pressure to the tank side when the load pressure detection circuit 20 is in an abnormally high pressure state.

Also in this case, a similar configuration is provided on the reduced diameter portion 27 side.

Next, the configuration inside the cap 7 will be described. A fitting structure 38 for restricting rotation of the spool 3 is provided in the cap 7.
Is provided. That is, the detent ring 39 is mounted, and the detent ring 39 includes the flange portion 41. As shown in FIG. 2, the flange portion 41 is formed with an opening 43 in which a pair of rectangular sides is formed in an arc shape.

A part of the flange 41 is cut and raised, and
The engaging claw 45 is engaged with a concave portion 47 formed on the cap 7 side. With this engagement structure,
The rotation of the detent ring 39 itself is restricted.

On the other hand, as shown in FIG.
The cross-sectional shape has a pair of rectangular sides formed into an arc shape, and the end 49 is inserted through the opening 43. Therefore, the rotation of the spool 3 is restricted by the rotation preventing ring 39.

 The operation will be described based on the above configuration.

First, it is assumed that the spool 3 is slid rightward in the figure.
By the sliding of the spool 3, the load side and the load pressure detection circuit 20 are communicated via the timing notch 31, and the load pressure is fed back.

At the same time, the metering notch
Since the pump port 15 and the load side are communicated via 29, pressure oil is supplied to the actuator.

Then, pressure oil corresponding to the opening of the metering notch 29 is supplied to the actuator while adjusting the discharge amount of a pump (not shown) based on the load pressure fed back.

By the way, the rotation of the spool 3 of the present embodiment is restricted by the fitting structure 38, so that the circumferential position does not change with the sliding operation.

The reason why the metering notch 29 and the timing notch 31 can be arranged at positions overlapping in the axial direction is that the rotation of the spool 3 is restricted.

As described above, the metering notch 29 and the timing notch 31 are arranged at positions overlapping in the axial direction, so that the communication between the load side and the load pressure detection circuit 20 and the communication between the pump port 15 and the load side have substantially the same timing. To be able to do with
The stroke of the spool 3 is also small.

According to the present embodiment, the spool valve itself can be made compact. This is because the stroke of the spool 3 can be reduced.

That is, the rotation of the spool 3 is restricted, and the metering notch 29 and the timing notch 31 are formed at positions substantially coincident in the axial direction and at different positions in the circumferential direction, so that the pump port 15 and the load side Communication timing,
This is because the timing of communication between the load pressure detection circuit 20 and the load side is substantially the same.

In this embodiment, since the metering notch 29 and the timing notch 31 are arranged symmetrically, there is no problem even if the spool 3 is shifted by 180 ° at the time of assembling, and the assembling work is easy accordingly. become.

Note that the present invention is not limited to the one embodiment.

The structure of the fitting structure 38 for restricting the rotation of the spool is not limited to the one shown in the drawing. For example, the rotation can be made directly by the fitting structure between the cap 7 and the end of the spool 3 without using the detent ring 39. May be restricted, and various shapes of the fitting structure 38 may be considered.

Further, the metering notch 29 and the timing notch 31 do not always need to be provided in a pair, and their positions,
The shape is not particularly limited.

(Effect of the Invention) As described in detail above, according to the spool valve of the present invention, the rotation of the spool is restricted, and the timing notch and the metering notch are located at substantially the same axial position and at different locations in the circumferential direction. Since the timing of communication between the load pressure detection circuit and the load side is substantially the same as the timing of communication between the pump port and the load side,
The stroke of the spool can be reduced, thereby making the device compact.

[Brief description of the drawings]

1 and 2 show an embodiment of the present invention.
FIG. 2 is a sectional view of the spool valve, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 1 ... housing, 3 ... spool, 7 ... cap,
15 ... Pump port, 20,22 ... Load pressure detection circuit, 29 ...
… Metering notch, 31 …… Timing notch, 38…
... Mating structure.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F15B 11/00-11/22 F16K 31/12

Claims (1)

(57) [Claims] 1. A housing having a pump port, a load port, and a load pressure detecting circuit, a spool slidably housed in the housing and having an end protruding from the housing, and protruding from the housing of the spool. A cap fixed to the housing so as to cover the portion, a timing notch formed on the spool and allowing the load port and the load pressure detection circuit to communicate with each other by sliding the spool, and a shaft formed on the spool and substantially the same as the timing notch A metering notch which communicates the load port with the pump port at substantially the same timing as the timing notch and the load pressure detection circuit communicate with each other by sliding the spool at different positions in the circumferential direction at different positions in the circumferential direction; The rotation of the spool is restricted by the fitting shape to the end of the spool Spool valve, characterized by comprising a fitting structure portion.