JP3523005B2 - Spool position control device for spool valve - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to spool position system GoSo location of the spool valve to improve the operating characteristics.

[0002]

2. Description of the Related Art FIG. 4 shows a typical structure of a conventional pilot operated slide spool valve. The main spool 2 is fitted in the body 1 so as to be slidable in the axial direction, and return springs 5 and 6 are provided in the covers 3 and 4 at both ends thereof. The main spool 2 is supported via 7, 8.

The body 1 is provided with a supply port 11, a pair of output ports 12 and 13, and a pair of tank ports 14 and 15. A land 16 is provided between the annular groove 11a corresponding to the supply port 11 and the annular groove 12a corresponding to the one output port 12, and the land 16 corresponds to the annular groove 11a corresponding to the supply port 11 and the other output port 13. Land 17 between the annular groove 13a
However, there is a land 18 between the annular groove 12a corresponding to the one output port 12 and the annular groove 14a corresponding to the tank port 14,
Lands 19 are provided between the annular groove 13a corresponding to the other output port 13 and the annular groove 15a corresponding to the tank port 15, respectively.

Further, the cover 3 is provided with a pilot port 21, and the cover 4 is provided with a pilot port 22.

Then, for example, the right pilot port 21
When pilot pressure P21 is applied to the main spool 2
When the pressure receiving cross section of A is A2, a leftward force of F2 = A2.P21 acts on the right end of the main spool 2. When the leftward force F2 becomes larger than the initial reaction force of the return spring 6, the main spool 2 moves leftward and moves to a position balanced with the reaction force of the return spring 6.

That is, when the spring constant of the return spring 6 is K6, the preset load (initial resistance) is F6, and the stroke of the main spool 2 is X2, the following equation (1) is established.

[0007] If this relationship is simply graphed, the relationship between the spool stroke X2 and the pilot pressure P21 is a straight line as shown by the solid line in FIG.

[0008]

However, in actuality, the main spool 2 moves to the left and the land 16 and the land
19 open, fluid from supply port 11 to one output port
When flowing toward the tank port 15 from the other output port 13 while flowing toward the main spool 2
To the right (returning direction) of the so-called fluid force, or sliding resistance force due to friction of the outer peripheral portion of the main spool 2 acts, and the movement of the main spool 2 is affected by these returning direction drag forces. As a result, as shown by the broken line in FIG. 5, there is a problem that linearity is lost and smooth movement is hindered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the positional accuracy of the spool by correcting the influence of the return force such as the fluid force acting on the spool in the spool valve. To do.

[0010]

SUMMARY OF THE INVENTION The 請 Motomeko invention described in 1, pilots introduced the axial position of the axially slidably mated main spool in the body to the ends of the main spool A spool position control device for a spool valve that is controlled by pressure is provided with a position feedback mechanism that applies a correction force that acts on the main spool to correct the position error caused by a reaction force in the return direction that acts on the main spool. Is fitted to the end of the main spool on the pilot pressure introduction side so as to be slidable in the axial direction, and when the pilot spool operates to receive the pilot pressure, the pilot pressure is applied to the main spool in the same way as the main spool. It receives and operates but does not receive the reaction force in the return direction, so it functions as a target value setting member for main spool position control. And pool, a spool position controller of the spool valve; and a modified pressure receiving pressure section of the main spool for receiving a controlled modified pressure in accordance with the position error of the main spool to axial position of the sub-spool.

The main spool, which operates by receiving the pilot pressure, receives a reaction force in the return direction, but the sub spool, which also operates by receiving the pilot pressure, does not receive such a reaction force in the return direction. It functions as a target value setting member for position control, and the main spool receives a correction pressure according to the position error with the sub spool in the correction pressure receiving section, and by providing a position feedback mechanism that operates in a direction to eliminate the position error. , The position accuracy of the main spool is improved and smooth movement of the main spool is realized without being affected by the return direction drag force exerted on the main spool represented by fluid force.

According to a second aspect of the present invention, the position feedback mechanism in the spool position control device for the spool valve according to the first aspect is provided at both ends of the main spool.

The position feedback mechanism provided at both ends of the main spool allows the return force of the return force to be exerted on the main spool, regardless of whether the main spool acts by the pilot pressure at one end or the pilot pressure at the other end. It works while canceling out the influence and improves the positional accuracy of the spool.

According to a third aspect of the present invention, the main spool in the spool position control device of the spool valve according to the first or second aspect is provided with a fluid control section for controlling fluid and a position. It is divided into a position feedback control unit provided with a feedback mechanism.

Then, the fluid control unit and the position feedback control unit are separately processed and formed so as to be incorporated into the body.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiment shown in FIGS. In addition,
The same parts as those of the conventional example shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows an example of a spool valve structure according to the present invention. Position feedback mechanisms 31 and 32 of the same structure are provided at both ends of the body 1 and the main spool 2, respectively.

The main spool 2 is divided into a fluid control unit 2a for controlling fluid and position feedback control units 2b, 2b provided with position feedback mechanisms 31, 32.

These position feedback mechanisms 31, 32
Is for applying a correction force to the main spool 2 in order to eliminate a position error caused by a reaction force in the return direction such as a fluid force acting on the main spool 2, and a shaft provided at both ends of the main spool 2. Sub spool 3 in holes 33 and 34
5 and 36 are slidably fitted to each other, and are formed around these sub spools 35 and 36.

At both ends of the main spool 2, a small diameter portion 37,
38 are formed respectively, and annular correction pressure receiving portions 41, 42 are formed between the main body portion of the main spool 2 and the small diameter portions 37, 38, respectively. The product of the pressure receiving area of these correction pressure receiving portions 41, 42 and the correction pressure acting on these correction pressure receiving portions 41, 42 becomes the correction force.

The sub spools 35 and 36 control the correction pressures acting on the correction pressure receiving portions 41 and 42 of the main spool 2, and the correction pressure supply ports formed in the covers 3 and 4 respectively. While controlling the opening degree of the opening control portions 45 and 46 formed between the correction pressure receiving portions 41 and 42 and the correction pressure receiving portions 41 and 42, and the drain ports 47 and 48 formed in the covers 3 and 4, respectively. The opening degrees of the opening control sections 49 and 50 formed between the correction pressure receiving sections 41 and 42 are controlled in directions opposite to the opening degrees of the opening control sections 45 and 46.

In the spring chambers 51 and 52 in the covers 3 and 4, fixed cylinder portions 53 and 54 are provided integrally with the covers 3 and 4 inside the springs 5 and 6, respectively. The portions 53 and 54 are provided with conduction holes 55 and 56, respectively. Smallest diameter portions 57 and 58 formed at both ends of the main spool 2 are slidably fitted in the fixed cylindrical portions 53 and 54, respectively.

Corresponding to the fixed cylindrical portions 53, 54, the sub spools 35, 36 are provided with small diameter portions 61, 62, respectively, and the small cylindrical portions 53, 54 have a small diameter portion 61, 62, respectively. Spring receiving parts 63, 64 that are locked by
Spring receiving portions 65 and 66 are integrally fitted to the tip end portions of 61 and 62, and springs 67 and 68 are interposed between the spring receiving portions 63 and 64 and the spring receiving portions 65 and 66, respectively. Further, springs 69 and 70 are interposed between the spring receiving portions 65 and 66 and the inner side surfaces of the covers 3 and 4, respectively.

The springs 67 and 68 are respectively the springs 69 and
The preset load (initial load) is set to be sufficiently larger than 70, and even if the springs 69 and 70 are bent, the springs 67 and 68 are set not to be bent by the reaction force.

The return springs 5 and 6, the springs 67 and 68, and the springs 69 and 70 are all compression coil springs, and the spring force of the outer return springs 5 and 6 is transmitted through the spring receiving portions 7 and 8 to the main. Although it acts only on the spool 2, the spring force of the inner springs 69 and 70 passes through the spring receiving portions 65 and 66, the springs 67 and 68, and the spring receiving portions 63 and 64, and the main spool 2
It also acts on both the sub spools 35 and 36.

Therefore, the main spool 2 is held in the neutral position by the reaction force of the springs 5, 6 and the springs 69, 70 via the spring receiving portions 7, 8 and the spring receiving portions 63, 64.

Next, based on FIG. 2, the correction pressure supply port
A path from 43 to the correction pressure receiving section 41 of the main spool 2 and a path from the correction pressure receiving section 41 to the drain port 47 will be described. Since the structure on the opposite side of the main spool 2 is the same, the description is omitted.

The correction pressure supply port 43 is communicated with an annular groove 71 formed on the inner diameter side of the cover 3, and the annular groove 71 passes through a radial hole 72 provided in the small diameter portion 37 of the main spool 2 and the inner diameter side. The annular groove 73 is communicated with the annular groove 73 formed in the outer peripheral surface of the sub spool 35.

The land 75 of the sub-spool 35 provided at a position adjacent to the left side of the annular groove 74 is an annular groove on the inner diameter side which communicates with the correction pressure receiving portion 41 of the main spool 2 through the radial hole 76. The opening control section 45 on the correction pressure supply side facing the opening 77 is opened and closed freely, and the opening degree of the opening control section 45 is controlled by the annular groove 74 and the land 75.

That is, when the opening control portion 45 is opened by moving the sub spool 35 to the left, depending on the opening degree,
The annular groove 73 and the annular groove 77 of the main spool 2 communicate with each other through the annular groove 74 of the sub spool 35.

On the other hand, the correction pressure receiving portion 41 of the main spool 2
The annular groove 77 communicating with the opening control portion 49 on the correction pressure drain side is provided facing the opening control portion 45 on the opposite side.
For this opening control unit 49, the land 75 of the sub spool 35
And an annular groove 81 formed adjacent to the left side of this land 75.
And are openable and closable.

The main spool 2 is provided with an annular groove 82 which communicates with the annular groove 77 by the annular groove 81.
82 communicates with an annular groove 85 via an axial hole 83 and a radial hole 84 provided in the main spool 2, and the annular groove 85 further includes a hole 86 provided in the body 1 and a cover 3.
Is communicated with the drain port 47 through a hole 87 provided in the.

Further, in order to prevent the variable pilot pressure supplied from the pilot port 21 and the constant correction source pressure supplied from the correction pressure supply port 43 from affecting each other, the cover 3 and the main spool 2 An annular groove 88 communicated with the drain port 47 and an annular groove 90 communicated with the annular groove 88 via a radial hole 89 with respect to a boundary surface where the small diameter portion 37 and the sub spool 35 slide with each other. Is provided.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described.

(Basic Operation) When pilot pressure is applied to the right pilot port 21 or the left pilot port 22, the main spool 2
Moves to the left or to the right in the same manner as in the conventional example to perform the switching operation. For example, when the main spool 2 moves to the left, the fluid flows from the supply port 11 to one output port 12, and When the main spool 2 moves to the right from the other output port 13 toward the tank port 15, the fluid flows from the supply port 11 to the output port.
It flows toward the tank port 14 from the output port 12 while flowing toward the tank port 14.

(Main Spool Neutral State) A fixed correction source pressure is supplied to the correction pressure supply ports 43 and 44, but in the state shown in FIG. 2, for example, the opening control section 45 on the correction pressure supply side. Is closed and the opening control section 49 on the correction pressure drain side communicates with the drain port 47, so that the correction pressure receiving section 41 of the main spool 2 has a drain pressure. Correction pressure receiving portion 42 on the opposite side of the main spool 2
Also has a drain pressure.

Further, the pilot ports 21 and 22 both communicate with the drain line of the pilot pressure control valve (not shown) at the time of neutral, and therefore the spring chambers 51 and 52 are connected.
Is the drain pressure, and therefore the drain pressure acts on the end faces of the small diameter portions 37, 38 of the main spool 2 together.

Therefore, the main spool 2 is held in the neutral position by the reaction force of the springs 5, 6 and the springs 69, 70 via the spring receiving portions 7, 8 and the spring receiving portions 65, 66.

(Main Spool Switching State) Now, a case will be described in which the pilot pressure P21 is applied to the pilot port 21 and the main spool 2 is switched to the left. The preset load of the spring 67 is set to be sufficiently larger than that of the spring 69, as described above.

When the pilot pressure P21 from the pilot port 21 is applied to the entire cross-sectional area of the sub spool 35, the sub spool 35 moves leftward relative to the main spool 2 and the opening control section 45 gradually moves. Opening and opening control section
By setting the spring constant and the preset load of the spring 67 so that the opening 49 is gradually closed, the opening areas (openings) A45 and A49 of the opening control unit 45 and the opening control unit 49 are set as shown in FIG.
The characteristics are set in advance so as to have the characteristics shown in (A) and (B).

The constant correction source pressure supplied to the correction pressure supply port 43 is P43, the correction pressure acting on the correction pressure receiving section 41 is P41, the drain pressure of the drain port 47 is substantially 0, and the opening control section 45 is used. Let A45 be the opening area of A, the opening area of the opening control section 49 be A49, the flow rate of the opening control section 45 be Q45, and the flow rate of the opening control section 49 be Q49. ) Holds.

[0042] However, K is a constant.

Then, the opening control unit 45 and the opening control unit 49 are positioned in series as viewed from the flow of the fluid, and the flow rates in the opening control unit 45 and the opening control unit 49 are equal (Q45 = Q49). 2) The following equation (4) is derived from (3).

[0044] Here, since the corrected source pressure P43 is a constant value (constant),
The correction pressure P41 acting on the correction pressure receiving portion 41 is calculated by the following equation (4)
As shown in ´), the opening area A45 of the opening control unit 45, 49,
This is a function with A49 as a variable.

P41 = f (A45, A49) (4 ') Also, the spring 68 on the opposite side is the same as the spring 67.
Set the preset load for the spring 70 large enough. Then, the spring constant of the return spring 6 is set to K
6, the preset load (initial resistance) is F6, the spring constant of the spring 70 is K70, the preset load is F70, the cross-sectional area of the small diameter portion 37 of the main spool 2 is A37, and the pressure receiving area of the correction pressure receiving portion 41 is Is A41 (correction power = A
41 · P41), the stroke of the main spool 2 is set to X2, and the return force such as the fluid force acting on the main spool 2 in response to the spool stroke X2 is F (X2
), Pilot pressure P2 at pilot port 21
When 1 is applied, each parameter is set by the following equation (5) so that the main spool 2 is displaced linearly as shown in FIG. 3 (C).

[0046] That is, the following expression (6) is derived from the expressions (5) and (4 ′).

[0047] However, α, β, γ, and δ are constants.

In this equation (6), f (A45, A49)
By acting as a correction term for the return force F (X2) and controlling A45 and A49 as shown in FIGS. 3 (A) and 3 (B), for example, to correct the return force F (X2). When the pressure P41 is generated, the stroke X2 of the main spool 2 is linearly proportional to the pilot pressure P21 as shown in FIG. 3 (C).

As described above, when the pilot pressure P21 is applied to the pilot port 21 and the main spool 2 moves to the left, the lands 16 and 19 that are opened as in the prior art.
Fluid force and sliding resistance force generated when the fluid flows out through

Therefore, when the linear movement of the main spool 2 is about to be hindered, the position feedback mechanism 31
And the sub-spool 35, which is not affected by the fluid force derived from the main flow passing through the lands 16 and 19, overstrokes relative to the main spool 2, and at the moment when the overstroke occurs, the opening control section 45 The opening A45 becomes larger, and conversely, the opening A49 of the opening controller 49 becomes smaller.

Therefore, according to the equation (4), the correction pressure receiving portion 41
The correction pressure P41 rises, and the correction force that pushes the main spool 2 to the left becomes stronger, and as a result, the correction force that cancels the return force F (X2) such as the fluid force acting on the main spool 2 is applied. It is generated from the correction pressure receiving unit 41.

Then, due to the correction force, the return direction drag force F
(X2) is canceled and main spool 2 is sub spool 35.
When the relative position (stroke position that is proportional to the pilot pressure P21) is set by the above, the opening control units 45, 49 also reach the preset opening, so that the linearity shown in FIG. 3C is maintained. Balance is maintained when In this way, the position feedback mechanism 31 on the right side functions.
The position feedback mechanism 32 on the left side functions similarly.

As described above, when the main spool 2 is not in the position where it should be due to the influence of the return force F (X 2 ) such as the fluid force acting on the main spool 2, the position feedback mechanisms 31, 32 Return direction drag F (X 2
) Is applied to the main spool 2 to correct the main spool 2 to its original position. By incorporating such position feedback mechanisms 31 and 32 in the spool valve, the position accuracy of the main spool 2 is improved. Not only can this be done, but the smooth movement of the main spool 2 can be realized.

In other words, the main spool 2 receives a reaction force in the return direction, but the sub spools 35 and 36 that operate in the axial direction by receiving the pilot pressure similarly to the main spool 2 do not receive such a reaction force in the return direction. The sub-spools 35 and 36 function as a target value setting member for position control, and the main spool 2 receives the correction pressure according to the position error with the sub-spools 35 and 36 on the correction pressure receiving portions 41 and 42 to set the position. It operates to eliminate the error.

The invention described in claim 2 corresponds to the three-position switching valve as in the illustrated embodiment in which the position feedback mechanisms 31 and 32 are provided at both ends of the main spool 2. In the two-position switching valve, a similar position feedback mechanism may be provided on one side of the main spool 2, and the invention described in claim 1 includes such a structure.

[0056]

According to the invention 請 Motomeko 1, wherein, according to the present invention, provided the position feedback mechanism for applying a modified force to eliminate the error in the main spool in response to a position error caused by the direction drag back acting on the main spool in the spool valve ,
The main spool, which operates by receiving the pilot pressure, receives the reaction force in the return direction, but the sub spool, which operates similarly by receiving the pilot pressure, does not receive the reaction force in the return direction, so this sub spool is the target of the main spool position control. The main spool functions as a value setting member, and the main spool receives the correction pressure according to the position error with the sub spool in the correction pressure receiving portion and operates in a direction to eliminate the position error, so that the main spool represented by the fluid force. The position accuracy of the main spool can be improved and smooth movement of the main spool can be realized without being affected by the reaction force acting in the return direction. That is, the sub-spool that is axially slidably fitted to the pilot pressure introduction side end of the main spool, and the main spool that receives the correction pressure controlled according to the position error of the main spool with respect to the axial position of the sub-spool. With the correction pressure receiving portion of the spool, a position feedback mechanism having a simple structure can be formed, and by this position feedback mechanism, the positional accuracy of the main spool can be improved without being affected by the return direction reaction force acting on the main spool. You can achieve smooth movement of the main spool.

According to the invention of claim 2, the invention of claim 1 can be applied to a three-position switching valve.

According to the third aspect of the invention, since the main spool is divided into the fluid control section and the position feedback control section, the main spool can be easily processed and the spool processing cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a spool position control device in the same spool valve.

FIG. 3 (A) is a characteristic diagram showing the relationship between the pilot pressure in the spool valve and the opening area of the correction pressure supply side opening control section 45, and FIG. 3 (B) is the pilot pressure and correction pressure drain side opening control. Characteristic diagram showing the relationship with the opening area in the portion 49,
(C) is a characteristic diagram showing the relationship between the pilot pressure and the stroke of the main spool.

FIG. 4 is a sectional view showing a conventional spool valve.

FIG. 5 is a characteristic diagram showing a relationship between pilot pressure and stroke of a main spool in a conventional spool valve.

[Explanation of symbols]

1 body 2 main spool 2a Fluid control section 2b Position feedback controller 31, 32 Position feedback mechanism 35, 36 sub spool 41, 42 Corrected pressure receiving part

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-61-206806 (JP, A) JP-A-51-46677 (JP, A) JP-A-7-174106 (JP, A) JP-A-9- 123933 (JP, A) Actually open Sho 60-79001 (JP, U) Actually open 6-82480 (JP, U) Japanese Patent Publication 2-58483 (JP, B2) Special Table 10-510616 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 3/24 F15B 13/043 F16K 11/07 F16K 31/122

Claims (3)

(57) [Claims] 1. A spool position control device for a spool valve, wherein the axial position of a main spool axially slidably fitted in a body is controlled by pilot pressure introduced at an end of the main spool. It is equipped with a position feedback mechanism that acts on the main spool with a correction force that eliminates the error caused by the reaction force in the return direction that acts on the main spool. The main spool, which is slidably fitted and receives a reaction force in the return direction when it operates by receiving pilot pressure, operates in response to the pilot pressure as with the main spool, but does not receive a reaction force in the return direction. The sub spool that functions as a control target value setting member and the axial position of the sub spool Spool position control device of the spool valve, characterized by comprising a modified pressure receiving pressure section of the main spool for receiving a controlled modified pressure in accordance with the position error of the main spool that. 2. A position feedback mechanism, the spool position control device according to claim 1, wherein the spool valve, characterized in that provided at both ends of the main spool. Wherein the main spool, a fluid control unit for controlling the fluid, according to claim 1 or 2 wherein the spool valve is characterized in that it is divided into a position feedback controller provided with the position feedback mechanism Spool position control device.