JPH0527448U - Switching valve - Google Patents

Abstract

(57) [Abstract] [Purpose] In a switching valve, when reducing the radial load applied to the spool by reducing the fluid pressure difference between the port side of the flow passage hole and the opposite side of the port side, Eliminates groove processing and keeps manufacturing costs low. [Structure] While forming a through hole 3 in the housing 2,
A spool 4 is axially slidably disposed inside the through hole 3, and flow paths from the inner peripheral surface of the through hole 3 to the ports 5, 6, 7, 8 and 9 in a direction orthogonal to the axis thereof. Holes 10, 11, 12,
A plurality of 13, 14 are provided, and the connection between the ports 5, 6, 7, 8, 9 is switched by the movement of the spool 4. In the spool-type switching valve 1, the flow to the port around the outside of the spool 4 at the time of port connection. Pressure balancing grooves 40, 41, 42, 43 having a rectangular cross section facing the passage hole are formed in an annular shape, and the diameter of the inner surface of the through hole 3 between the plurality of passage holes 10, 11, 12, 13, 14 is made uniform. And

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a switching valve suitable for switching a hydraulic circuit or the like.

[0002]

[Prior Art]

 As shown in FIG. 4 and FIG. 5, a general spool type switching valve has a cylinder port, a cylinder port, and a cylinder through which a spool g is slidably provided inside a through hole f formed in a housing d. A plurality of ports such as a tank port and a pump port are arranged, an annular groove b is formed in the through hole f of each port A, P, and each port A, P has a flow path through the annular groove b. When the hole C is connected to the through hole f and the port A and the port P are connected via the through hole a in the spool g, the pressure oil from the port P is discharged from the inner peripheral surface of the through hole f. It flows to the flow path hole C side A1 and the opposite side A2 of the annular groove b to the port A formed so as to be orthogonal to the axis.

At this time, if the cross-sectional area of the annular groove b that connects the flow path hole side A1 and the opposite side A2 is small, the pressure flowing from the port P to the flow path hole side A1 of the port A and the opposite side A2 thereof will be reduced. The oil has a load pressure on the flow path hole side A1 near the port A, but has the same pressure as the port P on the opposite side A2, and between the flow path hole side A1 of the port A and the opposite side A2. A pressure difference occurs in the spool g, and the spool g receives a radial load due to this pressure difference.

Therefore, in the conventional spool type switching valve, the sectional area of the annular groove b on the peripheral surface of the through hole f is increased, and the balancing groove e having a v-shaped cross section is formed on the surface of the spool g. The grooves e are filled with the pressure oil evenly so that the oil pressure is in a balanced state so that the axis of the spool g and the axis of the through hole f coincide with each other.

However, it is very difficult to form the annular groove b having a large cross-sectional area on the inner peripheral surface of the through hole f 1 in a small-sized switching valve in which a flow path is formed by milling, and the manufacturing cost is significantly increased. Since the height of the balancing groove e is small and the cross-sectional area of the balancing groove e is small, it was not possible to sufficiently eliminate the above pressure difference only by forming the balancing groove e without forming the annular groove b.

[0006]

[Problems to be solved by the device]

 The purpose of the present invention is to reduce the fluid pressure difference between the port side and the opposite side of the flow passage hole of the port formed by the drilled hole to reduce the radial load applied to the spool, but to the inner wall of the through hole. An object of the present invention is to provide a switching valve that can eliminate troublesome processing and can keep the manufacturing cost low.

[0007]

[Means for Solving the Problems]

 According to the present invention, a through hole is formed in a housing, and a spool is axially slidably disposed inside the through hole, and the spool is slidable in a direction orthogonal to an inner peripheral surface of the through hole. In a spool-type switching valve in which a plurality of port flow passage holes are provided and the connection between the ports is switched by moving the spool, the flow passage hole of the port is exposed on the outer periphery of the spool when the port is connected. The pressure balancing groove having a rectangular cross section is formed in an annular shape, and the diameter of the inner surface of the through hole between the plurality of flow path holes is made uniform.

[0008]

[Action]

 By forming an annular groove for pressure balancing with a rectangular cross section on the outer circumference of the spool, the fluid pressure in the flow passage hole of the port formed by the drill hole is balanced, and the radial load applied to the spool is reduced.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a switching valve 1 according to an embodiment of the present invention. Reference numeral 2 denotes a housing, through holes 3 are formed at both ends thereof, and a spool 4 is provided inside the through hole 3. Are arranged so as to be slidable in the axial direction.

The housing 2 is provided with a first cylinder port 5 and a second cylinder port 6 which are axially spaced from each other, and are provided outside the first cylinder port 5 and the second cylinder port 6. Is provided with a first tank port 7 and a second tank port 8 respectively, and a pump port 9 is provided between the first cylinder port 5 and the second cylinder port 6, and On the inner peripheral surface, the first cylinder port 5, the second cylinder port 6, the first tank port 7, the second tank port 8 and the flow passage holes 10 and 11 formed of drill holes leading to the pump port 9. , 12, 13 and 14 are orthogonal to the axial center of the through hole 3, and the diameter of the inner surface of the through hole 3 between the flow path holes 10, 11, 12, 13, and 14 is uniform. Has been formed.

Further, an annular groove 15 is formed near both ends of the inner peripheral surface of the through hole 3, and an O-ring 16 serving as a packing is fitted in the groove 15, and the first cylinder port is formed. 5, oil passage pipes (not shown) are connected to the other ends of the second cylinder port 6, the first tank port 7, the second tank port 8 and the pump port 9, respectively.

The spool 4 has a first land portion 17, a second land portion 18, a third land portion 19, a fourth land portion 20, and a fifth land portion 21. The first annular groove 22 is provided between the land portion 17 and the second land portion 18 and the second annular groove 23 is provided between the second land portion 18 and the third land portion 19. , A third annular groove 24 is provided between the third land portion 19 and the fourth land portion 20, and a fourth annular groove 24 is provided between the fourth land portion 20 and the fifth land portion 21. Each groove 25 is formed.

A relatively wide first pressure balancing groove 40 is formed in a ring shape outside the first annular groove 22 on the outer peripheral surface of the spool 4, and the first annular groove 22 and the second annular groove 22 are formed. The second pressure balancing groove 41 is provided between the third annular groove 23 and the third annular groove 23, and the third pressure balancing groove 42 is provided between the third annular groove 24 and the fourth annular groove 25. Fourth pressure balancing grooves 43 are similarly formed outside the annular groove 25. The pressure balancing grooves 40, 41, 42 and 43 are, for example, rectangular in cross section having a width larger than the depth.

Further, a through hole 26 formed by drilling is provided inside the spool 4 along the axial direction, and the annular grooves 22, 23, 24 and 25 and the through hole 3 are drilled by drilling. The first cylinder port 5 and the second cylinder port 6 are communicated with each other by holes 27, 28, 29 and 30 formed in the radial direction, and between the holes 28 and 29 inside the through hole 26. An isolating member 31 for isolating the is screwed.

A connecting body 32 connected to an operation lever or the like (not shown) is attached to one end of the spool 4 to close the through hole 26, and the other end of the spool 4 projects from the side surface of the housing 2. A protrusion 33 is formed, and a bolt 34 is screwed to the tip of the protrusion 33. Two stopper rings 35 and 36 are slid on the protrusion 33 between the bolt 34 and the side surface of the housing 2, respectively. A coil spring 37 that movably fits and holds the spool 4 in a neutral position is interposed between the stopper ring 35 and the stopper ring 36. Are covered by a cover 38.

Further, in FIG. 1, the pump port 9 passes through the second annular groove 23, the hole 28, the through hole 26, the hole 27 and the first annular groove 22 and is a flow path hole of the first tank port 7. 12 and further communicates with the flow path hole 13 of the second tank port 8 via another path passing through the third annular groove 24, the hole 29, the through hole 26, the hole 30 and the fourth annular groove 25. The first cylinder port 5 and the second cylinder port 6 are disconnected from the tank ports 7 and 8 and the pump port 9.

When the spool 4 moves to the side of the coupling body 32, the pressure oil flowing in from the pump port 9 passes through the second annular groove 23 and the hole 28, the through hole 26 and the hole 27, and the first annular groove 22. Through the flow passage hole 10 of the first cylinder port 5 and the communication from the pump port 9 to the first tank port 7, the second tank port 8 and the second cylinder port 6 is blocked. To be done.

At this time, as shown in FIG. 3, the second pressure balancing groove 41 having a rectangular cross section faces the flow passage hole 10 to the first cylinder port 5, and the cylinder port 5 side of the flow passage hole 10 side. Since A1 and its opposite A2 are connected, there is almost no pressure difference between the cylinder port 5 side A1 of the flow passage hole 10 and its opposite side A2, and an excessive radial load is not applied to the spool 4.

When the spool 4 moves to the opposite side, the pump port 9 and the flow passage hole 11 of the second cylinder port 6 are made to communicate with each other in the same manner, and the pump port 9 and the first cylinder port 5, The paths communicating with the first tank port 7 and the second tank port 8 are blocked.

At this time, the hydraulic pressure of the flow path hole 11 is balanced by the third pressure balancing groove 42, and the radial load applied to the spool 4 is reduced as in the case described above.

Although the case where the pressure oil flows into the cylinder ports 5 and 6 has been described above, when the pressure oil flows into the other ports, similarly, the pressure applied to the flow passage holes should be balanced. You can

[0023]

[Effect of the device]

 In the switching valve of the present invention, the pressure balancing groove having a rectangular cross section is formed on the outer periphery of the spool so as to face the flow passage hole to the connected inflow port, so that the port and the opposite side are formed by the pressure balancing groove. Even in a small switching valve where the pressure is balanced and the flow path hole is formed only by drilling, a large pressure difference does not occur between the inflow port side of the flow path hole and the opposite side, and the spool is too large. It is possible to prevent a large radial load from being applied.

Therefore, the conventional oil passage groove formed on the inner peripheral surface of the through hole facing the port is not required, so that troublesome machining can be reduced and the manufacturing cost can be significantly reduced. ..

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a switching valve according to an embodiment of the present invention.

2 is a cross-sectional view of the embodiment shown in FIG.

FIG. 3 is a longitudinal sectional view of a main part in a longitudinal direction of the embodiment shown in FIG. 1 in another state.

FIG. 4 is a cross-sectional view of a conventional switching valve.

FIG. 5 is a longitudinal sectional view of a main portion of a conventional switching valve in a longitudinal direction.

[Explanation of symbols]

 1 Switching Valve 2 Housing 3 Through Hole 4 Spool 5 First Cylinder Port 6 Second Cylinder Port 7 First Tank Port 8 Second Tank Port 9 Pump Port 10 Flow Path Hole 11 Flow Path Hole 12 Flow Path Hole 13 Flow path hole 14 Flow path hole 15 Recessed groove 16 O-ring 17 First land portion 18 Second land portion 19 Third land portion 20 Fourth land portion 21 Fifth land portion 22 First annular groove 23 2nd annular groove 24 3rd annular groove 25 4th annular groove 26 through hole 27 hole 28 hole 29 hole 30 hole 31 isolation member 32 connecting body 33 projecting portion 34 bolt 35 stopper ring 36 stopper ring 37 coil spring 38 cover 40 First pressure balancing groove 41 Second pressure balancing groove 42 Third pressure balancing groove 43 Fourth pressure balancing groove

Claims (1)

[Scope of utility model registration request] 1. A housing is provided with a through hole, and
A spool is axially slidably disposed inside the through hole, and a plurality of flow passage holes are provided from an inner peripheral surface of the through hole to a port in a direction orthogonal to the axial center of the through hole. In a spool-type switching valve that switches connection by moving the spool, a pressure balancing groove having a rectangular cross section is formed in an annular shape on the outer periphery of the spool so as to face a flow path hole of the port when the port is connected, and the plurality of flow paths are provided. A switching valve having a uniform inner diameter of the through hole between the holes.