JP3410029B2 - Switching valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching valve, and more particularly, the present invention relates to a sleeve having a supply port in communication with a source of pressurized fluid, a return port in communication with a fluid tank, and a control port in communication with a fluid passage, Also, the present invention relates to a switching valve including a slider slidably provided in the sleeve.

[0002]

2. Description of the Related Art Conventionally, as such a switching valve, for example, one shown in FIG. 3 has been known. In this apparatus, a sleeve 31 is connected through a supply passage 21 to a pressurized fluid source such as a pump P, a supply port 31a, two return ports 31b connected to a fluid tank T through a discharge passage 23, and fluid passages 25 and 26. It has two control ports 31c and 31d communicating with an actuator 35 such as a fluid pressure cylinder. Two control ports 3
1c, 31d have orifices 31ca, 31cb, 31da, 3 having openings substantially equal to the maximum stroke of the slider.
It forms 1 db.

A slider 20 'slides in the sleeve 31 in the axial direction with a predetermined stroke to perform switching. The slider 20 'includes the control ports 31c and 31 described above.
The land portion 20'a is provided at a position corresponding to d,
By moving the slider 20 ', the control ports 31c, 31
Orifices 31ca, 31cb, 31da, 31d of d
The opening of b is adjusted and switched.

[0004]

In the switching valve having the above-described structure, for example, the slider 20 'shown in FIG.
Is moved leftward, the pressurized fluid supplied from the supply port 31a to the left side valve chamber has a flow rate corresponding to the opening of the orifice 31cb of the control port 31c and the land 20'a of the slider 20 '. The fluid flows into the actuator 35 through the supply passage 25 through the orifice 31cb of the control port 31c. Further, the return oil from the actuator 35 returns from the supply passage 26 to the control port 31d, and a fluid having a flow rate according to the opening degree of the orifice 31db of the control port 31d and the land portion 20'b of the slider 20 'is supplied to the control port 31d. Enters the right side valve chamber through the orifice 31db, and is returned from the right side valve chamber to the fluid tank T through the return port 31b.

When the slider 20 'is moved to the right, contrary to the above case, the fluid flows from the supply port 31a to the right valve chamber, the control port 31d, the supply passage 26, the actuator 35, the supply passage 25, The control port 31c, the left valve chamber, the return port 31b, and the fluid tank T flow in this order.

In this case, the pressurized fluid is supplied to the supply port 31a.
To the control port 31c, and from the control port 31d to the return port 31b (when the slider 20 'moves leftward), or from the supply port 31a to the control port 31d.
To and from the control port 31c to the return port 31b (when the slider 20 'moves to the right), the flowing fluid causes an axial force on the slider 20'.
It acts in the direction opposite to the moving direction of the slider 20 ', that is, in the direction of closing the valve.

The force acting in the axial direction is called flow force. Conventionally, in order to reduce such a flow force, for example, as shown in FIG. 3, the slider 20 ′ in the vicinity of the return port 31b has an inclined cross-section and the inlet surface of the return port 31b is also inclined. Measures are taken to minimize the flow force by allowing the pressurized fluid to flow smoothly.

However, in order to reduce the flow force in consideration of such a flow state, it is necessary to perform complicated processing on the slider 20 'and the sleeve 31, which increases the cost of the switching valve. Was becoming. Further, it is actually difficult to reduce the flow force as calculated by such a shape, and it is difficult to control the flow force.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a switching valve which can be easily manufactured and can be reduced in cost.

[0010]

According to the present invention, there is provided a supply port communicating with a pressurized fluid source, a return port communicating with a fluid tank, and a control port communicating with a fluid passage. And a slider provided slidably in the sleeve, the slider has a land portion a corresponding to the supply port, and the supply port and the return port have openings. The above-mentioned problems can be achieved by a switching valve characterized in that the stroke of the slider is two to three times.

The present invention does not seek to eliminate the flow force of the prior art at all, but allows the flow force to exist essentially. However, since the flow force generated in this way does not change its degree of change depending on the opening of the switching valve and is constantly changed in the same direction, the switching valve may rattle during operation. By providing such a switching valve, a switching valve is provided so as to operate smoothly.

Further, according to the present invention, as shown in an embodiment, a pair of cylindrical motor coils arranged side by side in an axial direction in a housing, and provided at an axial position of the cylindrical motor coils so as to be movable in the axial direction. An armature axially moved by a driving force applied by a cylindrical motor coil, and a motor unit composed of a pair of spring members for urging the armature to a neutral position, a casing, and the inside of the casing connected to the armature in the axial direction. A control valve portion comprising a sleeve having a supply port communicating with a source of pressurized fluid, a return port communicating with a fluid tank, and a control port communicating with a fluid passage, and a slider slidably provided in the sleeve. It is preferable to apply to the switching valve including. In this case, the spring member comprises a disc spring having a peripheral portion attached to the housing and a central portion attached to the armature,
A peripheral portion and a central portion of the disc spring are preferably a switching valve connected by a plurality of narrow arms.

The narrow arms are preferably along a spiral path extending from the peripheral portion to the central portion, and the spiral paths drawn by the plurality of arms of the disc spring are in the same direction. More preferably,
Further, it is preferable that the arm of the disc spring is composed of a linear portion and an arc portion, and the plurality of arms draw a spiral path in the same direction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings illustrating an embodiment of the present invention. FIG. 1 shows a sectional view of an embodiment of a valve with a motor using a switching valve according to the present invention.

In this motor-equipped valve, the motor unit 15
Is housed in the housing 10 and the housing 10,
A plurality of (two in the embodiment) cylindrical motor coils 11 and 12 arranged coaxially in series, and the motor coils 11,
One armature 13 which is loosely fitted in the shaft 12 so as to be movable in the axial direction and moves in the axial direction by the driving force applied from the motor coils 11 and 12, and the armature 13.
Pair of spring members 1 for urging the spring toward the neutral position
It consists of 4. The armature 13 of the motor unit 15
The right front end of the is protruding from the housing 10.

A casing 29 of the valve portion 18 is fixed to the right end surface 13a of the housing 10 of the motor portion 15, and a slider 20 fixed to the right end of the armature 13 is slidably accommodated in the casing 29. Has been done.

A fluid source such as a pump P is connected to the valve portion 18 via a supply passage 21, and is connected to a fluid tank T via a discharge passage 23. Further, the fluid passages 25 and 26 are used for the actuator 3 such as a fluid cylinder.
Connected to 5. When the slider 20 of the valve portion 18 moves in the casing 29 due to the axial movement of the armature 13, the fluid from the fluid source P is supplied to the actuator 35, and the piston of the actuator 35 and the like are moved in the axial direction.

In the conventional valve with motor shown in FIG. 3, since the coil spring 14 'is used as the spring member for urging the armature 13, there is a large space in the axial direction for mounting the coil spring 14'. Will be needed. For this reason, the size of the motor-equipped valve becomes large, and it has been impossible to make the motor-equipped valve compact. Furthermore, in the conventional device, in order to hold the armature 13 at the central position of the housing 10 of the motor unit, the armature 13 is supported by the bearing 1.
Had to be supported by 7. For this reason, it has been difficult to reduce the size of the motor unit 15 in the conventional valve with a motor.

Therefore, in the motor-equipped valve of this embodiment, the spring member 14 is a disc spring, and the peripheral portion 14a of the disc spring 14 is fixedly attached to the housing 10 by the nut 16. Further, a hole 14b into which both ends 13a and 13b of the armature 13 described above are fitted is formed at the center of the disc spring 14 and the disc spring 14
Both ends 13 of the armature 13 fitted in the holes 14b of the
The nuts 19 allow the disc springs 14a and 13b to
It is attached to the.

The disc spring 14 according to the present invention has a peripheral portion 14a attached to the housing 10 as described above.
And a central portion 14b attached to the armature 13 are connected by a narrow arm 14c.

As a method of this connection, for example, as shown in FIG.
4a and the center part 14b are connected. In the embodiment shown in FIG. 2, the disc spring 1 having a circular shape is used.
4 has a spiral groove 14d (the hatched portion in FIG. 2 is the spiral groove 14d). In the embodiment shown in FIG. 2, the spiral arm 14c is formed by a combination of two arcuate portions 14c1 extending in the circumferential direction and a linear portion 14c2 connecting between the arcuate portions 14c1. .

In this embodiment, two arms 14c are formed between the peripheral portion 14a and the central portion 14b, but the number of arms 14c is equidistantly formed with respect to the center of the disc spring 14. However, the number is not limited to two. In this case, if the number of arms 14c is set to one, it becomes difficult to keep the central portion 14b at the central position of the disc spring 14 at all times, so it is preferable to make a plurality. Further, when the number of arms 14c is excessively increased, it becomes difficult to perform the work, so that it is preferable to use two or three arms 14c.

As described above, the disc spring 14
By holding the peripheral portion 14a and the central portion 14b of
Since the armature 13 is held by the disc spring 14 in the center portion 14b of the housing 10, a special bearing for holding the armature 13 in the center portion 14b can be omitted, and the structure is simplified.

In this embodiment, the disc spring 1
The reason why the arm 14c of No. 4 has a spiral shape is as follows. The peripheral portion 14a is fixed to the housing 10 by using the disc spring 14 of one plate, and the central portion 14b
When is fixed to the armature 13, the spring constant of the disc spring 14 becomes extremely high, so that the spring constant may be too large as a spring member of the motor portion of the valve with motor, which is not preferable.

Therefore, the peripheral part 14a and the central part 14b are connected by the narrow arm 14c so that the spring constant of the disc spring 14 can be set to an appropriate value.

In particular, as shown in the embodiment, the arm 14c is formed into a shape that follows the spiral path.
The length of c can be made sufficiently long, and the spring constant of the arm 14c, that is, the disc spring 14 can be lowered to facilitate setting to a desired value.

In this case, if all the arms 14c are shaped along a simple spiral in an arc shape, the spring constant of the obtained disk spring 14 in the radial direction also decreases at the same time, which is not always preferable. .

In order to prepare for such a case, in order to make the disc spring 14 have a desired spring constant in the axial direction and the radial direction, a combination of an arc shape and a straight line portion is used as shown in FIG.

Further, as described above, the arm 14 between the peripheral portion 14a and the central portion 14b of the disc spring 14 is provided.
By setting the number of c to be plural, the position of the central portion 14b is always held at the central position by the arm 14c, and a special bearing as shown by reference numeral 17 in FIG. 3 becomes unnecessary. .

Next, in the switching valve of the present invention, the sleeve 31 is connected to the fluid supply port 31a and the discharge passage 23 which communicate with the pressurized fluid source P such as a pump through the supply passage 21 as in the conventional switching valve described above. It is provided with two return ports 31b communicating with the tank T and two control ports 31c, 31d communicating with fluid passages 25, 26 communicating with an actuator 35 such as a fluid pressure cylinder.
On the other hand, the slider 20 is provided with three land portions 20a, 20b, 20b spaced apart in the axial direction as shown in FIG. 1, and each of the land portions 20a, 20b, 20b has a supply port 31a and a return port at both ends. It is located corresponding to port 31b. However, in the embodiment of the present invention, no land is formed at the control ports 31c and 31d.

Further, in the above-mentioned conventional apparatus shown in FIG. 3, the openings in the control ports 31c, 31d are small orifices 31ca, 31cb, as shown in FIG.
The orifices 31ca, 31cb, 31da, 31db are formed to have substantially the same size as the maximum stroke of the sleeve 31. On the other hand, in the device of the present invention, the size of the openings of the supply port 31a and the return port 31b is set to be 2 to 3 times the stroke of the slider 20. As an example, the slider 20 has a stroke of 0.5 mm.
In this case, the size of the openings of the supply port 31a and the return port 31b is set to 1.0 to 1.5 mm, which is 2-3 times larger.

In FIG. 1, reference numeral 40 denotes a differential transformer (LVDT), which detects the stroke of the slider 20.

In the switching valve of this embodiment having the above-mentioned structure, the cylindrical motor coils 11 and 12 of the motor section 15 are provided.
Is excited to move the armature 13 in the axial direction, for example, to the right, and the slider 20 connected to the armature 13 also moves to the right in the axial direction. The movement of the slider 20 determines the opening degree of the supply port 31a of the switching valve, and a predetermined amount of pressurized fluid flows into the left valve chamber from the supply port 31a according to the determined opening degree. The pressurized fluid that has flowed in is in the slider 20 after the inflow.
Therefore, the fluid flows to the control port 31c without being obstructed by the control port 31c. Therefore, the flow rate of the fluid from the control port 31c flows to the actuator 35 according to the opening degree of the slider 20 according to the excitation by the motor unit 15. On the other hand, the actuator 35 passes through the control port 26 and returns to the right valve chamber. Depending on the position of the slider 20, the land 20b of the slider 20 and the return port 31b cause the return port 31 to move.
The opening degree of b is determined, and the fluid having a flow rate according to the opening degree flows out from the right valve chamber to the tank T through the return port 31b.

With the above-mentioned structure, the fluid corresponding to the stroke of the slider 20 flows out from the control ports 31c and 31d, and a predetermined switching control can be performed. In addition, when the armature 13 is moved to the left, the flow of the pressurized fluid is opposite to the above.

In the present invention, the reason why the sizes of the openings of the supply port 31a and the return port 31b are set to be two to three times the stroke of the slider 20 will be described below.

Conventionally, since the size of the orifice is designed according to the flow rate of the switching valve, the present inventor has found that the supply port 31a of the present invention has an extremely narrow orifice as in the conventional example shown in FIG. 31ca, 31cb, 31da, 31
A switching valve provided with db was manufactured, and the flow force was measured using the switching valve. The result is shown in FIG.

In FIG. 4, the horizontal axis indicates the stroke of the slider 20, and the vertical axis indicates the flow force. As shown in FIG. 4, the flow force increases with the stroke of the slider 20, and has a peak at a position before the maximum stroke of the slider 20 (about 2/3 of the maximum stroke in FIG. 4). That is, in the state where the peak is exceeded (and before the maximum stroke), the magnitude of the flow force decreases. In addition,
When the slider 20 was moved specifically beyond the maximum stroke, and the slider 20 was further moved in the same direction for measurement, the magnitude of the flow force became zero.

In FIG. 4, the left side of the horizontal axis shows the slider 20 moved in one direction, and the right side shows the slider 20 moved in the opposite direction. Also,
In FIG. 4, when the peak is exceeded, there are two flow forces, which indicates that multiple measurement results were obtained.

The reason why the flow force is generated is as follows. Land 20a of slider 20 is supply port 31a
When the slider 20 is moved slightly to the right in FIG. 1 from the valve closed state in which the supply port 31a is completely closed, the supply port 31a opens slightly to form a throttle portion. The fluid flows into the valve chamber on the left side at a high velocity from the narrow gap of the throttle portion. Since the pressure of this fluid having a high flow rate decreases, as shown in FIG. 5A, the pressure distributions on the left and right wall surfaces of the left valve chamber are different, and the axial force in the closing direction of the slider 20, that is, in the left direction Occurs, this is flow force. A similar situation occurs in the right valve chamber.

As the slider 20 moves, the size of the throttle portion changes and the pressure distribution on the left and right wall surfaces of the valve chamber changes, so that the flow force changes as the slider 20 moves.

By the way, the inventor considers the reason why the peak of the flow force occurs as follows. As shown in FIG. 5B, when the slider 20 is moved beyond the supply port 31a formed of a narrow orifice, the fluid flowing from the supply port 31 into the valve chamber is as shown in FIG. The flow state changes from the flow state shown in Fig. 3 and flows toward the right side wall surface of the valve chamber, so that the flow force has a peak.

Moreover, due to the movement of the slider 20 or the like, the change in the flow direction of the fluid is such that the right wall surface of the valve chamber matches the right wall surface of the supply port 31a.
That is, it is considered to occur before the slider 20 reaches the maximum stroke. Therefore, the present inventors consider that the peak of the flow force occurs before the slider 20 reaches the maximum stroke.

If the flow force uniformly increases with the stroke change of the slider 20 until the slider 20 is changed to the maximum stroke, the slider 20
The operating system can be designed relatively easily. However, as shown in FIG. 4, when there is a peak of flow force before the maximum stroke, the change degree of the force acting before and after this peak changes. For this purpose, the slider 20
When the stroke of reaches the peak position before and after the above-mentioned peak position, the force acting on the cylindrical motor coils 11 and 12 of the motor part 15 changes, and therefore the operation of the armature 13 becomes uncertain, and therefore the slider 20 can be accurately controlled. Absent. If measures are taken against such a situation, the design of the operating system of the slider 20 becomes complicated.

On the other hand, in the present invention, the supply port 31
Since the opening degree of “a” is set sufficiently large, the flow force continues to change in one direction even when the slider 20 moves, and there is no phenomenon in which the peak is generated. Therefore, regardless of the change in the flow force of the slider 20,
Extremely smooth switching is possible. Further, since the changing direction of the action of the flow force does not change in this way, the load of the disc spring can be reduced in this embodiment, and no special measures are taken to cope with the change of the flow force. Therefore, the maximum current value supplied to the cylindrical coil can be reduced.

[0045]

According to the present invention, the existence of the flow force is allowed and the changing direction of the action of the flow force is not changed by the stroke of the slider, instead of making a difficult design for eliminating the flow force. By this, the force of the spring member of the motor part, particularly the disc spring when the disc spring is used, can be sufficiently weakened, and the maximum current value supplied to the cylindrical coil can be reduced accordingly, and the switching valve The device can be easily manufactured, the cost can be reduced, and the operation is reliable, so that the control is easy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view when a switching valve according to the present invention is configured as a valve with a motor.

FIG. 2 is a front view of a disc spring used in the present invention.

FIG. 3 is a cross-sectional view of a valve with a motor using a conventional switching valve.

FIG. 4 is a measurement diagram for explaining a problem that occurs when the orifice structure of the switching valve having the shape shown in FIG. 3 is used for the switching valve having the structure of the present invention, and the stroke of the slider is plotted on the horizontal axis. , The vertical axis shows the flow force.

FIG. 5 is a diagram illustrating a flow force generation mechanism.

[Explanation of symbols]

10 housing 11, 12 Motor coil 13 Armature 14 Disc spring 14a peripheral part 14b center 14c arm 14c1 arc-shaped part 14c2 Straight part 15 Motor part 16 nuts 18 Valve part 20 sliders 20a, 20b Land part 21 Supply passage 23 Discharge passage 25, 26 fluid passage 29 casing 31 sleeve 31a Supply port 31b Return port 31c, 31d Control port

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-1-105086 (JP, A) JP-A-51-115329 (JP, A) JP-A-60-69303 (JP, A) JP-A-5- 322057 (JP, A) JP-A-2-89883 (JP, A) JP-A-10-214715 (JP, A) JP-A-11-82767 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 11/07 F16K 31/06

Claims (5)

(57) [Claims] 1. A sleeve having a supply port communicating with a source of pressurized fluid, a return port communicating with a fluid tank, and a control port communicating with a fluid passage, and a slider slidably provided in the sleeve. In the switching valve,
The switching valve, wherein the slider has a land portion corresponding to the supply port, and the opening of the supply port and the return port is set to 2 to 3 times the stroke of the slider. 2. A pair of cylindrical motor coils arranged side by side in the housing in the axial direction, and a driving force provided by the cylindrical motor coils movably in the axial position of the cylindrical motor coils. A motor part including an armature axially moved by the armature and a pair of spring members for biasing the armature to a neutral position, a casing, and a supply port connected to the armature and communicating in the casing with a pressurized fluid source in the axial direction. A switching valve including a sleeve having a return port communicating with a fluid tank and a control port communicating with a fluid passage, and a control valve portion made of a slider slidably provided in the sleeve, wherein the slider supplies the supply It has a land portion corresponding to the port, and the openings of the supply port and the return port are 2 to 3 times the stroke of Ida,
The spring member comprises a disc spring having a peripheral portion attached to the housing and a central portion attached to the armature, and the peripheral portion and the central portion of the disc spring are connected by a plurality of narrow arms. A switching valve characterized in that 3. The switching valve according to claim 2, wherein the narrow arm is along a spiral path extending from the peripheral portion to the central portion. 4. The switching valve according to claim 3, wherein spiral paths drawn by a plurality of arms of the disc spring are in the same direction. 5. The switching valve according to claim 3, wherein the arm of the disc spring has a linear portion and an arc portion, and the plurality of arms draw a spiral path in the same direction.