JPH11351258A - Static pressure bearing, and hydraulic control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a static pressure bearing and a hydraulic control valve capable of easily constituting a throttle and a pocket forming the static pressure bearing while a hole inserted with a first member (a sleeve) and a second member (a spool) is a cylinder with high accuracy. SOLUTION: A sleeve 20 to be fitted in a valve body 10 and a spool 40 slidably fitted in the sleeve 20 and displaced in the sleeve 20 to switch the direction of a working fluid flowing in a plurality of ports Ps, Pc, Pt provided in the sleeve 20 and the valve body 10 are provided. A throttling member 30 is separately provided on an outer circumference of a pocket 25 provided in the sleeve 20, and a fluid from a fluid feeding means is fed to the pocket 25 through a throttle hole 31 provided in the throttling member 30. The spool 40 is pivotably supported in the sleeve 20 in a non-contact manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic bearing for supporting a second member in a hole of the first member in a non-contact manner, and a spool type hydraulic pressure control valve using the hydrostatic bearing. is there.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing an example of a conventional spool type hydraulic pressure control valve having a sleeve provided with a hydrostatic bearing.
As shown in the figure, the hydraulic control valve includes a valve body 100,
A sleeve 110 fixed in the valve body 100, a spool 120 slidably fitted in the sleeve 110,
Nozzle flapper mechanism 1 for controlling movement of spool 120
30 and displacement sensor 1 for detecting displacement of spool 120
40.

The operation of the hydraulic control valve will be briefly described. The hydraulic fluid supplied to the supply port Ps from a pump (not shown) is supplied to the passages 101L and 101R in the valve body 100.
Bearings 150, 15 provided on the sleeve 110 through
0 is supplied. The hydrostatic bearing 150 is a small-diameter throttle 150.
a and a plurality of pockets 150b. A plurality of sets are radially arranged with respect to the shaft center, and act as bearings by supplying a pressurized liquid thereto. The liquid supplied to the pocket 150b flows through the gap between the sleeve 110 and the spool 120 and flows out into the chambers 160, 160, respectively.
63R and 163L, and are discharged from passages 165L and 165.
Through R, return ports Pt, Pt return to the tank. By driving the flapper 131 of the nozzle flapper mechanism 130 right and left, the spool 120 is slid left and right, and the piston 171 of the cylinder 170 is driven. I do.

When the hydrostatic bearing 150 is provided as described above,
Since the spool 120 is supported in non-contact with the sleeve 110, the slidability of the spool 120 can be improved. By the way, in order to slide the spool 120 without rubbing in the sleeve 110, a predetermined gap is required between the outer diameter of the spool 120 and the inner diameter of the sleeve 110. If the gap is large, leakage occurs from this gap. Is an invalid flow rate, so a smaller one is desirable. Therefore, the spool 120 and the sleeve 110 are required to have a uniform cylindrical shape with a small gap over the entire length. As described above, since the sleeve 110 is a member that requires accuracy, generally, the sleeve 110 is precisely processed as a separate component from the valve body 100 and fixed to the valve body 100. In other words, since the sleeve 110 is provided as a separate component from the valve body 100, the cylindrical hole can be accurately machined over the entire length of the sleeve 110, and the spool 120 and the sleeve 110
Can be narrowed, and the leakage flow rate of the liquid from the gap can be reduced.

[0005]

As described above, when the hydrostatic bearing 150 is provided on the sleeve 110, the sleeve 110
It is necessary to form the aperture 150a and the pocket 150b on the inner side of the hole.
Therefore, the processing of the pocket 150b from the outer peripheral side of the sleeve 110 is impossible, and the processing from the inner peripheral side is also extremely difficult.

As described above, in the sleeve, it is necessary that the sliding hole of the spool has a cylindrical shape with high precision over the entire length, and furthermore, the inner side forming the throttle and the pocket of the hydrostatic bearing has a large-diameter hole having a large diameter. is there.

[0007] In the event that foreign matter is clogged in the hydrostatic bearing 150, the foreign matter is removed by the sleeve 110.
It is necessary to remove the whole from the valve body 100,
Its maintenance was not easy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned point, and an object of the present invention is to provide a high-precision cylinder while making a hole into which a second member (spool) of a first member (sleeve) is inserted into a high-precision cylinder. It is an object of the present invention to provide a hydrostatic bearing and a hydraulic control valve having a structure in which a throttle and a pocket forming a pressure bearing can be easily formed.

Another object of the present invention is to provide a hydrostatic bearing and a hydraulic pressure control valve having a structure capable of easily performing maintenance even if maintenance is required.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a second member having an outer diameter smaller by a predetermined dimension than the inner diameter of a hole provided in a first member. The second member is inserted into the hole of the first member in a non-contact manner by supplying the fluid from the fluid supply unit to the throttle hole provided on the first member side and the pocket having a larger diameter than the throttle hole. In the hydrostatic bearing to be supported, a pocket is provided in the first member, and a throttle member, which is another member, is attached to an outer periphery of a portion where the pocket of the first member is provided, and the throttle member communicates with the pocket. A throttle hole is provided, and the fluid from the fluid supply means is supplied to the pocket through the throttle hole. According to another aspect of the present invention, there is provided a spool mounted in a valve body, and a spool which is slidably fitted in the sleeve and displaces in the sleeve to switch a direction of a working fluid flowing through a plurality of ports provided in the sleeve and the valve body. And a hydrostatic bearing for supporting the spool in the sleeve in a non-contact manner by supplying the liquid from the liquid supply means to the throttle hole provided on the sleeve side and to a pocket having a larger diameter than the throttle hole. In the hydraulic pressure control valve, the static pressure bearing may be configured such that a throttle member, which is a separate member, is attached to an outer periphery of a pocket provided in the sleeve, and a fluid from the liquid supply means is supplied to the pocket through a throttle hole provided in the throttle member. Is supplied. Further, the present invention provides an outer diameter of a portion where the pocket of the sleeve is provided is made smaller than an outer diameter of another portion of the sleeve, and the cylindrical space formed between the small diameter portion and the inner diameter of the valve main body is provided. A diaphragm member is attached. Further, the present invention is characterized in that the sleeve and the throttle member are provided with an engagement portion which engages when the throttle member is attached to a small diameter portion of the sleeve to prevent the throttle member from rotating.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing a hydraulic pressure control valve using a hydrostatic bearing according to the present invention. As shown in FIG. 1, the hydraulic control valve includes a valve body 10 and a valve body 1.
0, a spool 40 slidably fitted in a hole of the sleeve 20, and a spool 40.
And a displacement sensor 60 for detecting the displacement of the spool 40. Hereinafter, each component will be described.

The valve body 10 has a supply port Ps connected to a pump (liquid supply means), not shown, and chambers 83L, 8 on both sides of a piston 81 of a cylinder 80 to be controlled.
Two control ports Pc, Pc connected to the 3R and two return ports Pt connected to the tank T are provided. In the interior of the valve body 10, passages 13 </ b> L and 13 </ b> L which branch the pressure fluid supplied from the supply port Ps to the sleeve port 21 described below and supply the branched fluid to the left and right static pressure bearings A
R and chambers 11L, 11 formed at both ends of the sleeve 20.
Passage 1 connecting R to nozzles 57L and 57R described below
5L and 15R, a central chamber 19 for introducing the liquid discharged from the nozzles 57L and 57R, and passages 17L and 17R connected from the central chamber 19 to two sleeve ports 23L and 23R described below.

The sleeve 20 is formed in a substantially cylindrical shape, and has a sleeve port 21 and a sleeve port 23 therein.
L, 23R are formed. The sleeve port 21 is connected to the supply port Ps, and the sleeve port 23L, 2
3R is connected to return ports Pt and Pt, respectively. Further, a portion between the sleeve port 21 and the sleeve port 23L, and the sleeve port 21 and the sleeve port 23L.
Portions between R are connected to control ports Pc and Pc, respectively.

On the other hand, outer peripheral portions at both ends of the sleeve 20
The outer diameter of the other portion of the sleeve 20 is made smaller than the outer diameter of the other portion, and a substantially cylindrical throttle member 30 is provided in a cylindrical space formed by the outer peripheral surface of the smaller diameter portion and the inner peripheral surface of the valve body 10. 30
, The hydrostatic bearings A, A are provided in this portion.

FIG. 2 is an exploded side sectional view of a main part of the hydrostatic bearing A, and FIG. 3 is a cross-sectional view (BB cross section of FIG. 2) of the assembled hydrostatic bearing A.

As shown in these figures, four pockets 25 are provided at equal intervals in the small diameter portion at the end of the sleeve 20.

On the other hand, the pockets 25 of the cylindrical diaphragm member 30 are located at positions facing the four pockets 25, respectively.
Four throttle holes 31 having an inner diameter smaller than the inner diameter of the throttle hole are provided, and a ring-shaped peripheral groove 33 (a channel that guides fluid to each throttle hole 31) is provided on the outer peripheral side of the portion where the throttle hole 31 is provided. O-rings 35, 36, and 37 are attached to one end surface, outer peripheral surface, and inner peripheral surface of the diaphragm member 30, respectively. The outer diameter of the throttle member 30 is the same as the outer diameter of the portion other than the small diameter portion of the sleeve 20, and the inner diameter of the throttle member 30 is substantially the same as the outer diameter of the small diameter portion of the sleeve 20.

Then, as shown in FIGS.
Although the aperture member 30 is inserted and attached to the small diameter portion of 0,
At this time, the position of each aperture 31 and the position of the pocket 25 are matched.

Returning to FIG. 1, the spool 40 has a cylindrical shape, and its outer diameter is formed so as to form a predetermined gap between itself and the inner wall surface of the sleeve 20 when inserted into the hole of the sleeve 20. ing. The spool 40 has small diameter portions 41L and 41R whose axial dimensions are slightly shorter than the distance between the sleeve port 21 and the sleeve port 23L and the distance between the sleeve port 21 and the sleeve port 23R.

The nozzle flapper mechanism 50 includes a torque motor 5
A pair of nozzles 57L, 57R sandwiching one flapper 53
Are opposed to each other. Nozzles 57L, 57R
Are connected to the passages 15L and 15R of the valve body 10.

As described above, the hydrostatic bearing A used for this hydraulic pressure control valve is constructed by attaching the throttle member 30 as a separate member to the outer periphery of the portion where the pocket 25 of the sleeve 20 is provided. Even if the large-diameter pocket 25 is on the inner peripheral side of the sleeve 20, the pocket 25 can be easily processed from the outer peripheral side of the sleeve. Therefore, when machining the pocket, the spool 40
Since the influence on the hole into which the hole is inserted can be reduced, the hole can be finished with high accuracy. In the event that foreign matter is clogged in the throttle hole 31 or the pocket 25, the throttle member 30 is removed from the sleeve 20 to remove the throttle hole 3.
The pocket 25 after the cleaning of 1 and the removal of the squeezing member 30
Can be easily performed without removing the sleeve 20 from the valve body 10.

Next, the operation of the hydraulic control valve will be briefly described. The pressure fluid supplied to the supply port Ps from a pump (not shown) passes through the sleeve port 21 and the passages 13L and 13R, passes through the throttle holes 31 of the left and right hydrostatic bearings A, and forms pockets 2.
5 to allow the spool 40 to be axially supported in the sleeve 20 in a non-contact manner, and then discharged through the gap between the sleeve 20 and the spool 40 into the chambers 11L and 11R, and the passage 15
L, 15R and the nozzles 57L, 57R and the flapper 5
3, the liquid is returned from the return port Pt to the tank T through the central chamber 19, the passages 17L and 17R, and the sleeve ports 23L and 23R.

Here, the operation of the hydrostatic bearing A will be described.
When the axes of the spool 40 and the sleeve 20 match, the pressure in each pocket 25 becomes the same. This is because the flow path resistance of the throttle hole 31, the pocket 25, and the gap between the spool 40 and the sleeve 20 are all equal. However, when the spool 40 is eccentric from the axis of the sleeve 20, the pressure in the pocket 25 on the approach side becomes high and the pressure in the pocket 25 on the side away from the sleeve 20 becomes low.
A force that pushes 0 back to the axis acts to correct the amount of eccentricity. As a result, the spool 40 floats inside the sleeve 20, and the spool 40 operates smoothly.

Next, when the flapper 53 is moved to the left, for example, by driving the torque motor 51, the pressure in the chamber 11L increases, and the pressure in the chamber 11R decreases, and as a result, the spool 40 moves to the right. I do. Therefore, the supply port Ps
Is supplied from the sleeve port 21 to the chamber 83L of the cylinder 80 via the left control port Pc, and drives the piston 81 rightward. At this time, room 83
The liquid in R is the right control port Pc, sleeve port 2
3R, returned to tank T from right return port Pt.
By adjusting the position of the spool 40 in this manner, the flow direction, flow rate, and pressure of the fluid to both control ports Pc are controlled. In this embodiment, the cylinder 80 is used as an actuator, but another actuator such as a motor may be used.

In order to prevent the throttle member 30 attached to the small diameter portion of the sleeve 20 from coming off the sleeve 20, as in the other embodiment shown in FIG.
The male screw 70 provided on the outer periphery of the ring-shaped presser screw 71 is screwed into the female screw 70 to tighten the aperture member 30.
May be configured to press down on the side surface.

When the throttle member 30 rotates with respect to the sleeve 20, the positions of the throttle hole 31 and the pocket 25 are shifted, and the throttle member 30 does not function as a hydrostatic bearing. In particular, when the holding screw 71 is screwed in as shown in FIG. 4, there is a great possibility that the throttle member 30 rotates with respect to the sleeve 20 by rotating together with the rotation of the holding screw 71. Therefore, as shown in FIG. 5, an engagement protrusion 73 is provided on the distal end surface of the small diameter portion of the sleeve 20, and a notch 38 that fits into the engagement protrusion 73 is provided on the end surface of the throttle member 30, so that both are fitted. In this case, the position of the aperture 31 and the position of the pocket 25 always match exactly, and there is no possibility that the position will shift thereafter. Here, the engaging projection 73 and the notch 38 form an engaging portion. Therefore, even if the aperture member 30 is fixed by the presser screw 71 shown in FIG. 4, no displacement of the aperture member 30 occurs. It goes without saying that the mechanism shown in FIG. 5 can be used even when the holding screw 71 is not used.

In the above embodiment, an example was shown in which the hydrostatic bearing according to the present invention was used for a hydraulic pressure control valve. However, this hydrostatic bearing is used not only as a hydraulic pressure control valve but also as a bearing for various other machines. That is, it can be used, for example, as a bearing for supporting a rotating shaft of a motor or a bearing for other machines. That is, the point is that a second member (corresponding to the spool 40) having an outer diameter smaller than the inner diameter of the hole by a predetermined dimension is inserted into a hole provided in the first member (corresponding to the sleeve 20). And
By supplying a fluid from a fluid supply means (corresponding to a pump (not shown)) to a pocket having a larger diameter than the throttle hole through a throttle hole provided on the first member side, the second member is connected to the first member. The present invention can be applied to any hydrostatic bearing having a structure in which a shaft is supported in a non-contact manner in a hole.

[0028]

As described in detail above, the present invention has the following excellent effects. Since the throttle hole is provided in the throttle member separate from the member provided with the pocket of the hydrostatic bearing, the pocket and the throttle hole can be processed independently of each other, and the first member (sleeve)
In addition, high-precision machining of the aperture member can be easily performed, and the hydrostatic bearing can be easily configured. Then, the first member (sleeve) can be accurately processed into a highly accurate cylindrical shape over the entire length. If the hydrostatic bearing of this configuration is applied to a hydraulic pressure control valve, it is possible to reduce the flow rate of leakage from the gap between the sleeve and the spool. This has a positive effect on the valve performance (pressure gain characteristics, flow characteristics, etc.).

Since the aperture member is formed as a separate member, it can be easily removed, and maintenance of the aperture and the pocket can be easily performed even in the event that foreign matter is clogged.

In the case where the sleeve and the throttle member of the hydraulic pressure control valve are provided with an engaging portion which engages when the throttle member is attached to the sleeve to prevent the throttle member from rotating, the pocket and the throttle hole are formed. Displacement can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a hydraulic pressure control valve using a hydrostatic bearing according to the present invention.

FIG. 2 is an exploded side sectional view of a main part of a hydrostatic bearing A portion.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a side sectional view of a main part of a hydrostatic bearing according to another embodiment.

FIG. 5A is an exploded side sectional view of a main part of a hydrostatic bearing portion according to another embodiment, and FIG. 5B is a right side view.

FIG. 6 is a sectional view showing an example of a conventional spool-type hydraulic pressure control valve provided with a static pressure bearing.

[Explanation of symbols]

 Reference Signs List 10 valve body 20 sleeve (first member) 25 pocket 30 throttle member 31 throttle hole 40 spool (second member) 50 nozzle flapper mechanism 60 displacement sensor Ps fluid supply port Pc control port Pt return port A static pressure bearing 38 notch (Engagement part) 73 engagement projection (engagement part)

Claims (4)

[Claims] 1. A second member having an outer diameter smaller than an inner diameter of the hole by a predetermined dimension is inserted into a hole provided in the first member, and fluid from the fluid supply means is supplied to the first member. In a hydrostatic bearing in which a second member is axially supported in a hole of the first member by being supplied to a throttle hole provided on the side and a pocket having a larger diameter than the throttle hole, a pocket is provided in the first member. A throttle member, which is a separate member, is attached to the outer periphery of the portion where the pocket of the first member is provided, and the throttle member is provided with a throttle hole communicating with the pocket, and the fluid from the fluid supply means is supplied to the throttle hole. Hydrostatic bearing, characterized in that the bearing is supplied to the pocket via a through hole. 2. A sleeve mounted within the valve body,
A spool that is slidably fitted in the sleeve and that switches the direction of the working fluid flowing through the plurality of ports provided in the sleeve and the valve body by displacing the inside of the sleeve; A hydraulic pressure control valve provided with a static pressure bearing for non-contactingly supporting the spool in the sleeve by supplying the throttle hole provided on the side and a pocket having a larger diameter than the throttle hole. A throttle member, which is a separate member, is attached to the outer periphery of the pocket provided in the above, and the fluid from the liquid supply means is supplied to the pocket through a throttle hole provided in the throttle member. Hydraulic pressure control valve. 3. An outer diameter of a portion of the sleeve where a pocket is provided is made smaller than an outer diameter of another portion of the sleeve, and a cylindrical space formed between the small diameter portion and the inner diameter of the valve body is formed in the cylindrical space. 3. An aperture member is attached.
The hydraulic pressure control valve as described. 4. The sleeve and the throttle member are provided with an engagement portion which, when the throttle member is attached to a small diameter portion of the sleeve, engages with each other to prevent rotation of the throttle member. The hydraulic pressure control valve according to claim 3.