JP2002195425A - Hydraulic control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control valve capable of simplifying the structure of a closing member and making an axial hole shallow. SOLUTION: This hydraulic control valve is provided with expanded diameter sections 42 and 43 formed from the opening section side of a spool hole 32, stopper sections 44 and 45 formed by the bottom faces of the expanded diameter sections 42 and 43, regulating step sections 48 and 49 formed on the outer periphery of a spool 33, center springs S and S assembled between the spool 33 and the expanded diameter sections 42 and 43, and spring receiving members 50 and 51 movably provided on the outer periphery of the spool 33. The spring receiving members 50 and 51 are pressed to the stopper sections 44 and 45 and the regulating step sections 48 and 49 by the elastic force of the centering springs S to keep the neutral position of the spool 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control valve using a centering spring for holding a spool at a neutral position.

[0002]

2. Description of the Related Art In a conventional hydraulic control valve shown in FIG. 3, a spool hole 2 is formed in a valve body 1 and a spool 3 is slidably incorporated in the spool hole 2. The spool 3 is formed with axial holes 4 and 5, and one end of each of the axial holes 4 and 5 is opened to an end surface of the spool 3. These axial holes 4, 5
Consists of large-diameter portions 4a and 5a having a large inner diameter and small-diameter portions 4b and 5b having a small inner diameter. Steps 6 and 7 are formed at the boundaries between the large-diameter portions 4a and 5a and the small-diameter portions 4b and 5b, respectively. are doing.

In addition, closing members 8 and 9 are fixed to the valve body 1, and the spool holes 2 are closed by the closing members 8 and 9. Then, the chamber partitioned by these closing members 8 and 9 and the spool 3 is
The pilot rooms 10 and 11 are provided. In addition, centering springs s, s are respectively incorporated in the pilot chambers 10, 11, and one ends thereof are inserted into the large diameter portions 4a, 5a of the axial holes 4, 5 of the spool 3. Note that the centering spring s,
One end of s is inserted into the axial holes 4 and 5 in order to reduce the amount of the centering springs s and s protruding from the valve body 1 to reduce the overall width of the valve.

On the other hand, rod members 8a, 9a are formed on the closing members 8, 9, and these rod members 8a, 9a are formed.
Stopper members 12 and 13 made of bolts are fixed to 9a. These stopper members 12 and 13 are inserted into the axial holes 4 and 5 of the spool 3 together with the rod portions 8a and 9a. The heads 12a, 13a of the stopper members 12, 13 can be inserted into the small diameter portions 4b, 5b.

[0005] Spring receiving members 14 and 15 are slidably provided on the outer periphery of the rod portions 8a and 9a and the stopper members 12 and 13, respectively. As shown in the figure, the spring receiving members 14 and 15 are pressed against both the steps 6 and 7 and the heads 12a and 13a of the stopper members 12 and 13 by the elastic force of the centering springs s and s. ing. By pressing both spring receiving members 14 and 15 against the heads 12a and 13a of the stopper members 12 and 13 in this manner, the spring receiving members 14 and 15 with respect to the valve body 1 can be pressed.
15 positions are determined. And these spring receiving members 1
The position of the spool 3 with respect to the valve body 1 is specified by contacting the steps 4 and 15 with the steps 6 and 7 formed on the spool 3 side. With the position specified in this way, the spool 3 is set to be held at the neutral position.

The proportional solenoids 16 and 17 are fixed to the valve body 1, and the proportional solenoids 16 and 17 control a pressure reducing valve (not shown) incorporated in the valve body 1. And the pilot pressure controlled by this pressure reducing valve is
Each pilot room 1 is connected via pilot passages 18 and 19.
It leads to 0,11. Also, the valve body 1
, The supply oil passage 20, the actuator oil passages 21, 22,
And tank oil passages 23 and 24 are formed.
0 to 24 communicate with the spool holes 2 respectively.

In the above-mentioned conventional hydraulic control valve, as shown, when a pilot pressure is introduced into the pilot chamber 10 from the state where the spool 3 is in the neutral position, a thrust is given to the spool 3 in the right direction in the drawing. When the right thrust of the spool 3 exceeds the elastic force of the centering spring s on the right side of the drawing, the centering spring s
The spool 3 moves rightward in the drawing while bending.
When the spool 3 is moved to the right in this manner, the actuator oil passage 21 and the supply oil passage 20 communicate with each other through the annular groove 27 formed in the spool 3, and the actuator oil passage 21 communicates through the notch 26 and the annular groove 28. Road 22 and tank oil passage 2
4 communicates. Accordingly, pressure oil from a pump (not shown) is supplied to the supply oil passage 20 → the annular groove 27 → the actuator oil passage 21 and the return oil from the actuator is supplied to the actuator oil passage 22 → the annular groove 28 → the notch 26. → It is discharged to the tank via the tank oil passage 24.

Contrary to the above, if the spool 3 is moved to the left in the drawing, the actuator oil passage 22
And the supply oil passage 20 communicate with the notch 25 and the annular groove 2.
The actuator oil passage 21 and the tank oil passage 23 communicate with each other via the line 7. Accordingly, pressure oil from a pump (not shown) is supplied to the supply oil passage 20 → the annular groove 28 → the actuator oil passage 22 and return oil from the actuator is supplied to the actuator oil passage 21 → the annular groove 27 → the notch 25. → It is discharged to the tank via the tank oil passage 23.

[0009]

In the above conventional example, the stopper members 12, 13 for determining the neutral position of the spool 3 are provided.
Are inserted into the axial holes 4 and 5, however, these stopper members 12 and 13 must be fixed to the valve body 1 side. Therefore, the stopper member is fixed to the valve body 1 via the closing members 8 and 9. However, in order to fix the stopper members 12 and 13, the rod portions 12a and 13a must be formed on the closing members 8 and 9, and the structure of the closing members 8 and 9 becomes correspondingly complicated. was there. Also, the axial holes 4,
Since the stopper members 12 and 13 corresponding to the depth of 5 were also required, there was also a problem that the component cost was increased.

On the other hand, when the spool 3 moves from the neutral position, it must be ensured that the tips of the stopper members 12, 13 do not hit the bottoms of the axial holes 4, 5. Therefore, conventionally, the axial holes 4 and 5 were formed deeply. However, when the axial holes 4 and 5 are formed deeply, when a notch or an annular groove or the like is formed, the thickness of the spool 3 at that portion becomes thin, resulting in insufficient strength or communication between the annular groove and the axial hole. There is also a problem that the shape of the notch or the annular groove is limited. SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic control valve which can simplify the structure of a closing member and can make an axial hole shallow.

[0011]

According to the present invention, there is provided a valve body, a spool hole formed in the valve body, a spool slidably incorporated in the spool hole, and a pair of openings respectively opened at both ends of the spool. The axial hole of
A closing member for closing the spool hole, a pilot chamber formed between the closing member and the end of the spool, and a main spring incorporated in the pilot chamber. It is assumed that the hydraulic control valve is inserted in

The first invention is based on the premise of the above-mentioned valve, while forming an enlarged portion formed from the opening side of the spool hole, a stopper formed by the bottom surface of the enlarged portion, and an outer periphery of the spool. A regulating step, a centering spring incorporated between the spool and the enlarged diameter portion, and a spring receiving member movably provided on the outer periphery of the spool,
The elastic force of the centering spring presses the spring receiving member against the stopper portion and the regulating step portion to maintain a neutral position of the spool. In a second aspect based on the first aspect, the main spring maintains a free length when the spool is at the neutral position, one end of which contacts the closing member, and the other end of which contacts the bottom of the axial hole. It is characterized in that it is configured to contact.

[0013]

In the embodiment shown in FIG. 1, a spool hole 32 is formed in a valve body 31 and a spool 33 is slidably incorporated in the spool hole 32. The spool 33 is formed with axial holes 34 and 35, and one end of each of the axial holes 34 and 35 is opened in the end surface of the spool 33. Further, plate-shaped closing members 38 and 39 are fixed to the valve body 31 with bolts B, and the spool holes 32 are closed by these plate-shaped closing members 38 and 39. The plate-shaped closing members 38 and 39 and the spool 33
Are defined as pilot chambers 40 and 41.

The pilot chambers 40 and 41 incorporate main springs 36 and 37, respectively, and one ends thereof are inserted into axial holes 34 and 35 of a spool 33. These main springs 36 and 37 maintain their free length when the spool 33 is at the neutral position as shown in the figure. In addition, in this free length state, the main springs 36, 37 have one ends thereof abutting on the closing members 38, 39 and the other ends thereof have the bottom portions 34a, 35 of the axial holes 34, 35.
a. Therefore, when the spool 33 is at the neutral position, the elastic force of each of the main springs 36, 37 does not act on the spool 33.

On the other hand, at both ends of the spool 33, small-diameter portions 46 and 47 having small outer diameters are formed, and regulating steps 48 and 49 are formed by the bottom surfaces of the small-diameter portions 46 and 47.
Is formed. As shown in FIG. 2, the enlarged diameter portions 42, 4 having a large inner diameter are provided on the opening side of the spool hole 32.
3, and the stopper portions 44, 45 are formed by the bottom surfaces of the enlarged diameter portions 42, 43. And, between the enlarged diameter portions 42 and 43 and the spool 33,
Centering springs S, S are incorporated respectively. These centering springs S, S have smaller spring constants than the main springs 36, 37, and have a predetermined initial elastic force when the spool 33 is at the neutral position.

Further, spring receiving members 50 and 51 are slidably provided on the outer periphery of the spool 33. The spring receiving members 50 and 51 are moved by the elasticity of the centering springs S and S to form the stopper portions 44 and 4.
5 and the regulating steps 48 and 49 are respectively pressed. When the spring receiving members 50 and 51 are pressed against the stopper portions 44 and 45, the positions of the spring receiving members 50 and 51 with respect to the valve body 31 are determined. Then, when the regulating step portions 48 and 49 of the spool 33 are brought into contact with the spring receiving members 50 and 51 whose positions are specified, the position of the spool 33 with respect to the valve body 31 is determined.
With the position specified in this way, the spool 33
Is set to be held at the neutral position. That is,
The neutral position of the spool 33 is maintained only by the initial elastic force of the centering springs S, S.

The proportional solenoids 52 and 53 are fixed to the valve body 31, and the proportional solenoids 52 and 53 control a pressure reducing valve (not shown) incorporated in the valve body 31. The pilot pressure controlled by the pressure reducing valve is guided to the pilot chambers 40 and 41 via the pilot passages 54 and 55. The valve body 31 has a supply oil passage 56, an actuator oil passage 57,
58 and tank oil passages 59 and 60 are formed, and these oil passages 56 to 60 communicate with the spool holes 32, respectively.

Next, the operation of this embodiment will be described. As shown, from the state where the spool 33 is in the neutral position,
When pilot pressure is introduced into the pilot chamber 40, the spool 3
3 is given a thrust in the right direction in the drawing. When the right thrust of the spool 33 exceeds the elastic force of the centering spring S on the right side in the drawing, the spool 33 moves rightward in the drawing while bending the centering spring S. When the spool 33 moves rightward even slightly, the main spring 37 also bends. Therefore, if the spool 33 moves to the right slightly from the neutral position,
The spool 33 moves to a position where the force obtained by adding the elastic force of the main spring 37 to the elastic force of the centering spring S and the thrust given by the pilot pressure balance. When the spool 33 moves to the right as described above, the main spring 3
6 is in a free state.

When the spool 33 moves rightward as described above, the actuator oil passage 57 and the supply oil passage 56 communicate with each other through the annular groove 61 formed in the spool 33,
The actuator oil passage 58 and the tank oil passage 60 communicate with each other via the notch 64 and the annular groove 62. Accordingly, pressure oil from a pump (not shown) is supplied to the supply oil passage 56 → the annular groove 61 → the actuator oil passage 57, and the return oil from the actuator is supplied to the actuator oil passage 58 → the annular groove 62 → the notch 64. → It is discharged to the tank via the tank oil passage 60.

Conversely, when pilot pressure is introduced into the pilot chamber 41, a thrust in the left direction in the drawing is given to the spool 33. When the leftward thrust of the spool 33 exceeds the elastic force of the centering spring S on the left side in the drawing, the spool 33 moves leftward in the drawing while bending the centering spring S. Spool 3
When 3 moves to the left even a little, the main spring 3
6 also deflects. Therefore, if the spool 33 moves to the left from the neutral position even slightly, the spool 33 will be attached to the elastic force of the centering spring S by the main spring 3.
6 moves to a position where the force obtained by adding the elastic force of No. 6 and the thrust given by the pilot pressure balance.

When the spool 33 moves to the left as described above, the actuator oil passage 58 and the supply oil passage 56 communicate with each other through the annular groove 62 formed in the spool 33.
The actuator oil passage 57 and the tank oil passage 59 communicate with each other via the notch 63 and the annular groove 61. Therefore, pressure oil from a pump (not shown) is supplied to the supply oil passage 56 → the annular groove 62 → the actuator oil passage 58, and the return oil from the actuator is supplied to the actuator oil passage 57 → the annular groove 61 → the notch 63. → It is discharged to the tank via the tank oil passage 59.

According to the above embodiment, since the centering springs S, S are provided on the outer periphery of the spool 33, the stopper portions 44, 45 can be directly formed on the valve body 31 around the spool 33. Therefore, the closing members 38 and 39 need only be simple plate-like members that close the spool hole 32. Therefore, the closing members 38, 3
9 can reduce the cost of parts. Further, according to this embodiment, the stopper member as in the conventional example can be dispensed with, so that the cost can be reduced accordingly.

Further, since there is no need to insert a stopper member into the axial holes 34 and 35, it is not necessary to make the axial holes deep. Therefore, when a notch, an annular groove, or the like is formed in the spool 33, there is no inconvenience such that the thickness of the portion is reduced or the annular groove communicates with the axial hole. That is, there is no problem that the shape of the notch or the annular groove formed in the spool 33 is limited.

The elasticity of the centering springs S, S need only be strong enough to maintain the neutral position of the spool 33, so that a thin spring with a small spring constant is sufficient. If such a thin spring is used, the space for installing the centering springs S, S, is also small. Therefore, even if the centering springs S, S are incorporated on the outer periphery of the spool 33 as described above, the size of the valve body 31 hardly changes.

Further, in this embodiment, when the spool 33 is at the neutral position, the main springs 36, 37 have a free length. If the main springs 36 and 37 have a free length, the elastic force does not act on the main springs 36 and 37, so that the assembling work of the main springs 36 and 37 becomes easier. However, in the present invention, the initial load may be applied to the main springs 36 and 37 when the spool 33 is in the neutral state. When an initial load is applied to the main springs 36 and 37, the main springs 36 and 37 having a smaller spring constant than the case where the above-mentioned free length is set are used.
37 can be used. This is because the main springs 36 and 37 are bent when the spool 33 is at the neutral position, so that a predetermined spring force required at the time of a full stroke can be obtained even if the spring constant is small. . When the main springs 36 and 37 having a small spring constant are used, the size of the main springs 36 and 37 can be reduced.

If an initial load is applied to the main springs 36, 37, when the spool 33 is switched from the neutral position, one of the main springs 36, 37 does not become free. That is, when the main springs 36 and 37 are in a free state, they rattle and cause noise, but there is no such problem if an initial load is applied.

[0027]

According to the first aspect, since the centering spring is provided on the outer periphery of the spool, the stopper can be directly formed on the valve body side. Therefore, the structure of the closing member can be simplified, and
Parts cost can be reduced. In addition, since the stopper member is not inserted into the axial hole, it is not necessary to make the axial hole particularly deep. For this reason, the axial hole can be made shallow, and when forming a notch or an annular groove in the spool, there is no inconvenience that the thickness of the portion becomes thin or the annular groove communicates with the axial hole. .

According to the second aspect of the present invention, when the spool is at the neutral position, no elastic force is generated by the main spring, so that the assembling work of the main spring is facilitated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment.

FIG. 2 is an enlarged view of a main part of the embodiment.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

 31 Valve Body 32 Spool Hole 33 Spool 34, 35 Axial Hole 34a, 35a Bottom 36, 37 Main Spring 38, 39 Closing Member 40, 41 Pilot Chamber 42, 43 Enlarged Diameter 44, 45 Stopper 46, 47 Small Diameter 48 , 49 Regulatory step 50, 51 Spring receiving member S Centering spring

Claims (2)

[Claims] 1. A valve body, a spool hole formed in the valve body, a spool slidably incorporated in the spool hole, a pair of axial holes opened at both ends of the spool, and the spool A closing member for closing the hole, a pilot chamber formed between the closing member and the end of the spool, and a main spring incorporated in the pilot chamber. One end of the main spring is inserted into an axial hole of the spool. Hydraulic control valve
An enlarged diameter portion formed from the opening side of the spool hole, a stopper portion formed by the bottom surface of the enlarged diameter portion, a regulating step formed on the outer periphery of the spool, and a portion between the spool and the enlarged diameter portion. With a built-in centering spring and a spring receiving member movably provided on the outer periphery of the spool,
A hydraulic control valve, wherein a spring receiving member is pressed against a stopper portion and a regulating step portion by an elastic force of the centering spring to maintain a neutral position of the spool. 2. The main spring, wherein the main spring has a free length when the spool is in the neutral position, one end of which contacts the closing member, and the other end of which contacts the bottom of the axial hole. The hydraulic control valve according to claim 1.