JP3763185B2 - Switching valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a switching valve used in a fluid pressure circuit such as oil or air.
[0002]
[Prior art]
A switching valve is used for control to switch the circuit configuration of a fluid circuit such as oil or air.
The switching valve includes a valve housing to which a plurality of fluid pipes and passages (hereinafter referred to as fluid passages) are connected, and a valve shaft member fitted in the valve housing so as to be movable in the axial direction. Depending on the relationship between the outer peripheral shape of the member and the inner peripheral shape of the valve housing, by changing the axial position of the valve shaft member relative to the valve housing, the continuity relationship between the plurality of fluid flow paths introduced into the valve housing is changed. This valve shaft member can be operated by operating means (for example, solenoid of solenoid valve, lever or button of man-powered valve, cam or link mechanism of mechanically operated valve, etc., to change the axial position relative to the valve housing. Thus, the switching control of the target circuit configuration is realized.
[0003]
By the way, the “poppet valve type” and the “spool valve type” are known as the basic structure principle of the switching valve that switches the circuit configuration according to the axial position of the valve shaft member.
FIG. 5 shows the structure of a spool valve type 2-position 4-port switching valve.
The spool valve 100 includes a valve housing 110 having four ports 131, 132, 133, and 134 and a spool 150 that slides in a fluid passage 120 in the valve housing 110. The spool 150 includes two land portions 151 and 152, and annular groove portions 153, 154, and 155 disposed on both sides of the land portions 151 and 152. In the state of FIG. 4, the port 131 and the port 134 are communicated, and the port 132 and the port 133 are communicated.
When the spool 150 is moved in the direction of arrow R in the figure, the land 151 closes the inner peripheral portion 122 of the fluid passage 120. By this action, the port 131 and the port 133 are communicated, and the port 132 and the port 134 are communicated.
[0004]
FIG. 6 shows the structure of a poppet type 2-position 3-port switching valve.
The poppet valve 200 includes a housing 210 having three ports 211, 212, and 213 and a spool 250 that slides in a fluid passage 220 in the housing. The spool 250 has a land portion 251, and the land portion 251 selectively abuts against the wall surfaces 221 and 222 defining the fluid passage 220 of the housing 210 to perform sealing.
[0005]
In the state of FIG. 6, the port 211 and the port 213 communicate with each other. In FIG. 5, when the spool 250 is moved in the arrow L direction, the land 251 seals the wall surface 221, and the port 212 and the port 213 are communicated.
In this poppet valve, the contact mechanism between the fluid circuits is applied in addition to the contact between the members in the axial direction by the operation means of the valve shaft member, and in some cases the pressure of the fluid is applied to the contact between the members. Due to the self-sealing effect that strengthens, there is an advantage that an almost complete blocking state can be configured.
This type of poppet valve is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-196471.
[0006]
[Problems to be solved by the invention]
In the above-described “spool valve type” switching valve, the number of ports is not limited, and various fluid flow paths can be connected to each other. For example, in a hydraulic circuit as shown in FIG. The flow path of the hydraulic circuit can be easily controlled by using one 2-position 4-port switching valve illustrated in the figure, which is a typical spool valve type switching valve.
However, in the spool valve type, the fluid circuits are separated from each other by a land fitting area between the inner peripheral surface of the valve housing and the outer peripheral surface of the valve shaft member existing between the annular grooves. The diameter of the part requires a minimum clearance to allow axial sliding of the valve shaft member relative to the valve housing.
[0007]
For this reason, it is impossible to make the continuity relationship between the fluid flow paths completely cut off. Especially when there is a large pressure difference between the adjacent fluid flow paths, There is an inconvenience that the fluid leaks from the high pressure side to the low pressure side through the gap in the fitting area.
Therefore, in a system that dislikes leakage flow between the fluid flow paths, this spool valve type cannot be adopted, and it is necessary to use a poppet valve type. That is, when the two-position three-port switching valve illustrated in the figure, which is a typical poppet valve type switching valve, is used, the cutoff state of the continuity relationship between the fluid flow paths is in the axial direction between the valve shaft member and the valve housing. Since it is performed by the contact relationship (at the opening surface of the fluid flow path), a complete blocking state is realized.
[0008]
However, on the principle that the shut-off state is constituted by the axial contact between the valve members, the structure in which two or more contact portions in the axial direction are simultaneously brought into contact simultaneously in both valve members is difficult in the work of the valve member. Even if it is realized, the productivity is poor and the production cost is high. Therefore, the number of ports of the fluid flow path that can be switched by the movement of one valve shaft member is as shown in FIG. The number of ports is limited to 3 ports. If the contact portions at a plurality of locations of both valve members are not completely contacted simultaneously, there is no advantage over the spool valve type.
[0009]
However, if there are 3 ports, for example, as shown in FIG. 5, it is necessary to use two 2-position 3-port switching valves illustrated in FIG. 7 in the hydraulic circuit, the hydraulic circuit itself becomes complicated, and the spool valve type This leads to an increase in production costs and the number of maintenance inspections.
An object of the present invention is to provide a switching valve that eliminates the disadvantages of the spool valve type and the poppet valve type as described above.
[0010]
[Means for Solving the Problems]
The main point of the present invention is that the floating ring member is fitted together with the floating ring member so as to be movable in the axial direction in the valve housing.
That is, the switching valve according to the present invention includes, as basic means, a housing member, a valve shaft member provided inside the housing member and capable of moving in the axial direction within the housing member, and externally fitted to the valve shaft member so as to be movable in the axial direction. A floating ring-shaped member, a first chamber at both ends of the housing which is inside the housing member and partitioned by a valve shaft member, a third chamber and a second chamber at an intermediate portion, a first chamber formed in the housing, and a first chamber A communication passage connecting the three chambers, a pressure fluid supply port formed on the wall surface of the housing member of the first chamber, a first flow port, a second flow port and a discharge port formed on the housing wall surface of the second chamber, A flange portion is provided inside the first flow port and the second flow port and contacts the outer end surface of the floating ring-shaped member.
Then, by the axial movement of the valve shaft member and the floating ring-shaped member, one of the first and second flow ports is switched to a position communicating with the pressure fluid supply port and the other to the discharge port.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a two-position four-port switching valve according to the present invention. The valve housing 1 and the valve shaft member 2 fitted to the valve housing 1 are slidable to the left and right. It is comprised from the floating ring member 3 fitted by.
The valve housing 1 is formed with a valve chamber surrounded by a peripheral wall portion 4 and end wall portions 5 and 5 at both ends, and the valve chamber is formed in the first chamber 7, the second chamber 8, and the third chamber 6 in the axial direction. Formed from.
[0012]
A pressure fluid supply port 14a that communicates from the outside to the outer end side of the first chamber 7 and a discharge port 15 that communicates to the outer end side of the second chamber 8 from the outside pass through the peripheral wall portion 4 respectively. A communication passage 14b that branches from the pressure fluid supply port 14a and communicates with the third chamber 6 passes through the inside.
Further, the first flow port 12 passes through the peripheral wall portion 4 from the inner peripheral surface of the first inner flange portion 28 to the outside, and the second flow port opens from the inner peripheral surface of the second inner flange portion 29 to the outside. 13 penetrates.
[0013]
For example, the pressure fluid supply port 14a is connected to a pipe L1 from a pump P which is a hydraulic oil supply source of the hydraulic circuit shown in FIG. 5, and the discharge port 15 is connected to a pipe L2 to the oil tank T. Yes.
Further, for example, a pipe L3 from one port a of the double acting cylinder A of the hydraulic circuit shown in FIG. 5 is connected to the first flow port 12, and the second flow port 13 is also connected from the other port b. Pipe line L4 is connected.
[0014]
The valve shaft member 2 includes a first valve rod portion 16, a first piston portion 31, a columnar intermediate portion 18, a second piston portion 32, and a second valve rod portion 20. The intermediate portion 18 has an axial direction. A small-diameter portion 33 having an annular groove is formed in the central region, and the first valve rod 16 and the second valve rod 20 penetrate the end wall portions 5 and 5 of the valve housing 1 in a slidable and oil-tight manner and are externally provided. Protruding.
The first valve rod portion 16 or the second valve rod portion 20 is coupled with operating means, for example, a solenoid of a solenoid valve (see FIG. 5), a lever of a manpower operated valve, a cam for mechanical operation, a link mechanism, and the like.
[0015]
The outer peripheral surfaces of the first piston portion 31 and the second piston portion 32 are slidably and oil-tightly fitted in the first chamber 7 and the third chamber 6, and the outer peripheral surface of the intermediate portion 18 is the first inner flange portion. There is an appropriate gap 34 between the two peripheral surfaces having a smaller diameter than the inner peripheral surface of 28 and the second inner flange portion 29. A narrower first annular groove 35 and a second annular groove 36 are formed at both ends of the small diameter portion 33, and the first communication port 24 penetrates from the outer end surface of the first piston portion 31 to the first annular groove 35. In addition, the second communication port 25 passes through the second annular groove 36 from the outer end surface of the second piston portion 32.
A floating ring member 3 shorter than the small diameter portion 33 is slidably and oil-tightly fitted on the outer peripheral surface of the small diameter portion 33, and the length of the floating ring member 3 is located at both end positions of the small diameter portion 33. The length is such that the first annular groove 35 or the second annular groove 36 is not covered.
The floating ring member 3 is appropriately larger in diameter than the inner peripheral surfaces of the first inner flange portion 28 and the second inner flange portion 29 of the valve shaft member 2 and only an appropriate gap 27 from the second chamber 8 of the valve housing 1. Small diameter portions 3c and 3d having a small diameter and substantially the same diameter as the intermediate portion 18 are formed at both ends.
[0017]
Therefore, both end surfaces 3a and 3b of the floating ring member 3 and the inner side surfaces of the first inner flange portion 28 and the second inner flange portion 29 form an appropriate abutting surface so that they can abut against each other. The end surfaces of the small diameter portions 3c, 3d of the floating ring member 3, the end surface 31a of the first piston portion 31 and the end surface 32a of the second piston portion 32 of the valve shaft member 2 form a contact surface so that they can contact each other. It has become.
[0018]
The operation of the two-position four-port switching valve according to the second embodiment will be described. The valve shaft member 2 has the first valve stem portion 16 or the second valve stem portion 20 as operating means, for example, a solenoid of a solenoid valve (see FIG. 5) is switched to the two positions of the position shown in FIG. 3 and the position shown in FIG.
When the valve shaft member 2 moves left to the position shown in FIG. 1, the floating ring member 3 is pressed by the right side step portion of the small diameter portion 33 of the valve shaft member 2 and moves left, and the outer periphery of the left end surface of the floating ring member 3 The region 3 a is in close contact with the inner peripheral region 28 a on the right side surface of the first inner flange portion 28, and the end surface of the small diameter portion 3 d of the floating ring member 3 is in close contact with the left step portion 32 a of the second piston portion 32 of the valve shaft member 2. In addition, the outer peripheral region 3b of the right end surface of the floating ring member 3 is separated from the left side surface of the second inner flange portion 29, and the right step portion 31a of the first piston portion 31 of the valve shaft member 2 is a small diameter portion of the floating ring member 3. It moves away from the end face of 3c.
[0019]
As a result, the first flow port 12 communicates with the first annular groove 35 of the valve shaft member 2, and the second flow port 13 is connected to the first annular groove 35 and the second annular groove of the valve shaft member 2 by the floating ring member 3. 36 and is communicated with the second chamber 8, that is, the discharge port 15.
That is, in the position state of the valve shaft member (see FIG. 3), the pressure fluid supply port 14 a is connected to the first flow port through the first chamber 7, the first communication port 24, the first annular groove 35, and the gap 34. 12 and the second circulation port 13 is connected to the discharge port 15 through the gap 34 and the second chamber 8 (gap 27).
[0020]
Thus, the hydraulic fluid supplied from the hydraulic fluid supply source (for example, the pump P in FIG. 5) of the hydraulic circuit via the pipe L1 flows in from the pressure fluid supply port 14a and flows out from the first flow port 12 to the pipe. The hydraulic oil that is supplied to one port a of the double acting cylinder A in the hydraulic circuit via the path L3 and flows out from the port b of the double acting cylinder A flows from the second flow port 13 via the pipe L4. The oil is discharged from the discharge port 15 to the oil tank T through the pipe line L2. Thereby, one operation of the double acting cylinder A is performed.
[0021]
When the valve shaft member 2 moves rightward from the position shown in FIG. 1 to the position shown in FIG. 2, the valve shaft member 2 slides to the right with respect to the floating ring member 3 in a stationary state, and eventually the first of the valve shaft member 2. The right side step portion 31a of the one piston portion 31 contacts the small diameter portion 3c of the floating ring member 3 and presses the floating ring member 3 to the right. Then, the outer peripheral area 31 a of the left end surface of the floating ring member 3 is separated from the inner peripheral area of the right side surface of the first inner flange portion 28, and the outer peripheral area 3 a of the right end surface of the floating ring member 3 is the left side of the second inner flange portion 29. The left side step portion 31a of the first piston portion 31 of the valve shaft member 2 is in close contact with the small-diameter portion 3c of the floating ring member 3, and the right side of the second piston portion 32 of the valve shaft member 2 The step portion 32 a is separated from the small diameter portion 3 d of the floating ring member 3.
[0022]
As a result, the first flow port 12 is blocked from the first annular groove 35 of the valve shaft member 2 by the floating ring member 3, communicates with the second chamber 8, that is, the discharge port 15, and the second flow port 13 floats. The ring member 3 is cut off from the second chamber 8, that is, the discharge port 15, and communicates with the second annular groove 36 of the valve shaft member 2 through the gap 34.
That is, in the position state of the valve shaft member (see FIG. 2), the pressure fluid supply port 14a is connected to the second flow port through the communication passage 14b, the third chamber 6, the second communication port 25, and the second annular groove 36. 13, and the first circulation port 12 is connected to the discharge port 15 via the gap 34 and the second chamber 8 (gap 27).
[0023]
Thus, the hydraulic oil supplied from the pump P, which is the hydraulic oil supply source of the hydraulic circuit, via the pipe L1 flows in from the pressure fluid supply port 14a, flows out from the second circulation port 13, and passes through the pipe L4. The hydraulic fluid that is supplied to the port b of the double acting cylinder A in the hydraulic circuit and flows out from the port a of the double acting cylinder A flows from the first flow port 12 through the conduit L3 and flows from the discharge port 15 to the conduit. It is discharged to the oil tank T through L2. Thereby, the other operation of the double acting cylinder A is performed.
[0024]
FIG. 3 shows another embodiment of the present invention.
The housing 4 a of the switching valve 1 a according to the present embodiment does not include a communication path that communicates the first chamber 7 and the third chamber 6. The valve shaft member 2 a has a communication port 40 in its small diameter portion 33. The first chamber 7 and the third chamber 6 are communicated with each other through the communication ports 40 and 24 and 25 formed in the piston portions 31 and 32.
[0025]
【The invention's effect】
According to the switching valve of the present invention, a poppet valve is formed by fitting together a floating ring member in a valve housing so that the floating ring member can be moved in the axial direction. The advantages inherent to the mold are provided, and the flow path switching in the fluid flow path switching within the valve is performed completely at the axial contact surface, so that there is no leakage between the flow paths and the flow path switching is performed completely.
[0026]
At the same time, there is no difficulty in work accuracy due to simultaneous contact at a number of locations, and multi-port switching, which is an advantage unique to the spool valve type, is possible.
That is, according to the present invention, it is possible to obtain a switching valve that has only the advantages of the poppet valve type and the spool valve type and eliminates the disadvantages of both.
[0027]
Particularly in the two-position four-port switching valve according to claim 2, the first hollow is partitioned by the floating ring member in the hollow portion of the valve housing by flowing in from the pressure fluid supply port and discharging from the outlet port. One of the parts is on the high pressure side, and the other hollow area is on the low pressure side, and the differential pressure acts on the contact part of the floating ring member and the valve shaft member to press the floating ring member against the fixed contact part. work.
Accordingly, the pressing force for pressing the floating ring member is the pressing force by the differential pressure added to the pressing force by the operating means, and the close contact between the floating ring member and each contact portion becomes even stronger.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a 2-position 4-port switching valve according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a 2-position 4-port switching valve according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of a 2-position 4-port switching valve according to a second embodiment of the present invention.
FIG. 4 is a hydraulic circuit diagram to which the 2-position 4-port switching valve according to the embodiment of the present invention is applied.
FIG. 5 is a sectional view of a conventional 2-position 4-port switching valve (spool valve type).
FIG. 6 is a cross-sectional view of a 2-position 3-port switching valve (poppet valve type) in the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Valve housing 2 Valve shaft member 3 Floating ring member 4 Peripheral wall part 5 End wall part 6 3rd chamber 7 1st chamber 8 2nd chamber 12 1st flow port 13 2nd flow port 14 Pressure fluid supply port 15 Outflow port 16th 1 valve rod portion 17 first flange portion 19 second flange portion 20 second valve rod portion 24 first communication port 25 second communication port 28 first inner flange portion 29 second inner flange portion 31 first piston portion 32 second Piston portion 33 Small diameter portion 35 First annular groove 36 Second annular groove P Pump T Oil tank A Double acting cylinder (actuator)
a, b Ports L1-4

Claims (2)

A housing member;
A valve shaft member provided inside the housing member and movable in the axial direction within the housing member;
A floating ring-shaped member externally fitted to the valve shaft member so as to be axially movable;
A first chamber at both ends of the housing that is inside the housing member and partitioned by the valve shaft member, a third chamber, and a second chamber at the intermediate portion;
A communication path connecting the first chamber and the third chamber formed in the housing;
A pressure fluid supply port formed in the wall surface of the housing member of the first chamber;
A first flow port, a second flow port and a discharge port formed in the housing wall surface of the second chamber;
A flange portion disposed inside the first flow port and the second flow port and contacting the outer end surface of the floating ring-shaped member;
A two-position four-port characterized in that one of the first and second flow ports is switched to a pressure fluid supply port and the other is connected to a discharge port by the axial movement of the valve shaft member and the floating ring-shaped member. Directional control valve. A housing member;
A valve shaft member provided inside the housing member and movable in the axial direction within the housing member;
A floating ring-shaped member externally fitted to the valve shaft member so as to be axially movable;
A first chamber at both ends of the housing that is inside the housing member and partitioned by the valve shaft member, a third chamber, and a second chamber at the intermediate portion;
A communication path connecting the first chamber and the third chamber formed in the valve shaft member;
A pressure fluid supply port formed in the wall surface of the housing member of the first chamber;
A first flow port, a second flow port and a discharge port formed in the housing wall surface of the second chamber;
A flange portion disposed inside the first flow port and the second flow port and contacting the outer end surface of the floating ring-shaped member;
A two-position four-port characterized in that one of the first and second flow ports is switched to a pressure fluid supply port and the other is connected to a discharge port by the axial movement of the valve shaft member and the floating ring-shaped member. Directional control valve.

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