JP2000240652A - Hydrostatic bearing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrostatic bearing structure capable of surely inhibiting a direct sliding between a first member and a second member even in the case of using water as a pressure fluid. SOLUTION: Between a guide plate 12 and a slider 13 which have sliding relationship, the sliding surfaces 14a-14c of the slider 13 are provided with projection-like parts 20 projected toward the sliding surfaces 33a-33c of the guide plate 12. The projection-like parts 20 collide with the sliding surfaces 33a-33c of the guide plate 12 during non-formation of a hydrostatic fluid thin film between the sliding surfaces 14a-14c, 33a-33c, thereby securing a clearance gap between the sliding surfaces 14a-14c and 33a-33c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static pressure receiving structure for supplying a pressurized fluid between sliding surfaces of a first member and a second member in a sliding relationship to form a static pressure fluid thin film.

[0002]

2. Description of the Related Art As a static pressure receiving structure of this type, there is a structure in which a pressurized liquid is supplied between sliding surfaces of a first member and a second member to form a static pressure liquid thin film. Oil is generally used as the pressurized liquid. However, due to the high cost and difficult handling properties of the oil, the oil used for forming the hydrostatic thin film has been recovered and reused.
Therefore, a closed circuit for circulating the oil is required and the cost is increased. In addition, the oil has a problem of waste oil treatment after its useful life.

[0003] In order to solve such a problem, it has been proposed to use water as a pressurized liquid. If water is used as the pressurized liquid, it is not necessary to re-use it like oil, and it is not necessary to provide a closed circuit for circulation, because of its availability and ease of handling.

[0004]

However, water has a higher surface tension than oil. Therefore, when the static pressure liquid thin film is not formed, the first member and the second member are adsorbed by the surface tension of the water remaining between the sliding surfaces, and the gap between the sliding surfaces becomes narrow. ing. As a result, when the sliding of both members is resumed, the pressurized water cannot enter between the sliding surfaces, and therefore, the hydrostatic thin film is not formed,
The first member and the second member were slid directly. In other words, the improvement of the low friction sliding and wear resistance, which is the original purpose of the static pressure receiving structure, has been hindered.

[0005] Even in the case of other liquids such as oil other than water, the above-mentioned problems occur to some extent as compared with the case of gas. Further, even when gas is used as the pressurized fluid, a similar problem occurs if sliding of both members is started in a state where the static pressure gas thin film is not sufficiently formed.

The present invention has been made in view of the problems existing in the prior art described above, and has as its object the purpose of, for example, using the first fluid even when water is used as a pressurized fluid.
An object of the present invention is to provide a static pressure receiving structure capable of reliably preventing direct sliding between a member and a second member.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, at least one of the first member and the second member has a protrusion protruding toward the other slide surface. This is a static pressure receiving structure in which a protruding portion abuts on the other sliding surface when a static pressure fluid thin film is not formed, so that a gap is secured between the two sliding surfaces.

According to the second aspect of the present invention, the protruding portion is set to such a height that when the hydrostatic thin film is formed, the protruding portion is separated from a state where it abuts against the other sliding surface. In the invention according to claim 3, the pressurized fluid is a liquid.

According to a fourth aspect of the present invention, there is provided a pressurized gas supply means for supplying a pressurized gas between sliding surfaces of the first member and the second member, and forming a hydrostatic thin film between the sliding surfaces. When you do
By supplying the pressurized gas by the pressurized gas supply means,
This is a static pressure receiving structure configured to secure a gap between sliding surfaces to facilitate the entry of a pressurized liquid.

(Function) In the invention of the first to third aspects of the present invention, between the sliding surfaces of the first member and the second member,
When the static pressure fluid thin film is not formed, a gap is secured by the protrusion on one side of the first member or the second member abutting against the sliding surface on the other side. Therefore, the pressurized fluid supplied at the next sliding of the first member and the second member can easily enter between the sliding surfaces. As a result, the static pressure fluid thin film is formed reliably and promptly, and the low friction sliding between the first member and the second member and the improvement in wear resistance by the static pressure receiving structure are favorably achieved.

According to the fourth aspect of the present invention, when the sliding between the first member and the second member starts, the gap between the sliding surfaces between the first member and the second member is widened by the pressurized gas. That is,
The pressurized gas is more likely to enter the minute gap than the pressurized liquid. Therefore, the pressurized liquid can easily enter between the sliding surfaces following the pressurized gas. As a result, the static pressure liquid thin film is reliably and promptly formed, and the low friction sliding between the first member and the second member and the improvement in wear resistance by the static pressure receiving structure are favorably achieved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first and second embodiments of the present invention applied to a dresser for a grinding wheel will be described. In the second embodiment, only differences from the first embodiment will be described, and the same members will be denoted by the same reference numerals and description thereof will be omitted.

(First Embodiment) As shown in FIGS. 1 and 2, a base block 11 is provided on a multi-axis table device (not shown) of a grinding machine. Can be moved. The guide plate 12 as the first member is formed by bending a metal plate and fixed to the upper surface of the base block 11. Guide surface 1
2a is formed on the upper surface of the guide plate 12.
The guide plate 12 protrudes in both directions from within the width of the base block 11.
Has made.

The slider 13 as a second member is made of metal and is mounted on the guide surface 12a. Legs 14
The slider 1 moves along the curved shape of the guide plate 12.
3 are integrally formed on both side ends, and are fitted to the guide portion 33 in an uneven relationship. The slider 13 is guided by the guide portion 33 via the leg portion 14 by the driving of the motor 15, so that the slider 13 can rotate about the virtual axis L along the guide surface 12 a.

The holder 31 is arranged on the upper surface of the slider 13. The dressing wheel 32 is rotatably held by the holder 31 and is driven to rotate by a motor (not shown). Tip (dress point) D of dressing wheel 32
Exists on the virtual axis L described above. Therefore, the dressing wheel 32 is tilted about the dress point D by the rotation of the slider 13.

Then, as shown in FIG. 4, when the grinding wheel 101 of the grinding machine is formed (dressed), the dress point D of the rotating dressing wheel 32 is rotated by moving the base block 11 in the direction of the arrow. This is done by sequentially contacting each forming point S at the tip of the rotating grinding wheel 101 and cutting a predetermined amount at each location. The tip of the grinding wheel 101 has a curved surface, but the dressing grinding wheel 32 has a slider 13.
By the tilting accompanying the rotation of, any molding point S is identified. In addition, in order to facilitate understanding, only three forming points S are shown in the figure, but actually, there are many forming points S constituting the tip shape of the grinding wheel 101.

Next, the static pressure receiving structure of the dresser for a grinding wheel will be described. As shown in FIGS. 2 and 3, the static pressure pockets 16 extend in the extending direction of the legs 14 on the upper surface 14 a, the side surface 14 b, and the lower surface 14 c in each leg 14, which is the sliding surface on the slider 13 side. A plurality are formed at predetermined intervals (only one location is shown in FIG. 2). The static pressure pocket 16 is concavely recessed, and a discharge port 17 is formed at the center of the concave.

The water pump 18 is connected to the discharge port 17 via a discharge pipe 21 and is connected to the water storage tank 1.
9 can be supplied to the static pressure pocket 16 by pressurizing the water.
When the grinding wheel 101 is dressed, pressurized water is supplied to the static pressure pocket 16, so that sliding surfaces 14 a to 14 c and 33 between the guide plate 12 and the slider 13 are provided.
A static pressure liquid thin film is formed between a to 33c. Therefore, the slider 13 floats on the guide plate 12, and the sliding resistance between the two can be reduced.
As a result, smooth and accurate sliding movement of the slider 13 can be achieved, and the dressing of the grinding wheel 101 can be performed accurately. Although not shown, the pressurized water used for forming the hydrostatic thin film is applied to the sliding surfaces 14a to 14c and 33a to 33c.
It is discharged from the space and is not supplied to the static pressure pocket 16 again.

In the present embodiment, the protrusion 20
Are the respective surfaces 14a to 14c of the leg portion 14 of the slider 13
, Each is formed so as to protrude toward each surface 33a to 33c of the guide portion 33 which is a sliding surface facing the guide plate 12 side. The protruding portion 20 is formed of a cylindrical synthetic resin pin body and is planted on each of the surfaces 14a to 14c. A plurality of protruding portions 20 are arranged alternately with the static pressure pockets 16 on each of the surfaces 14a to 14c. The tip of the projection 20 has a convex spherical shape.

When the supply of pressurized water to the static pressure pocket 16 is stopped after the dressing of the grinding wheel 101 is completed,
Sliding surface 14a between guide plate 12 and slider 13
14c, the hydrostatic liquid thin film is about to disappear from between 33a to 33c. Therefore, the slider 13 tends to lower the disappearance of the thickness of the hydrostatic thin film by its own weight, and the upper surfaces 14a and 33a of the leg 14 and the guide 33 approach each other. However, the protrusion 2 on the upper surface 14a side of the leg 14
When the “0” abuts on the upper surface 33 a of the guide portion 33, further downward movement of the slider 13 is prevented. Therefore, a gap is secured between the upper surfaces 14a and 33a of the leg portion 14 and the guide portion 33.

When the static pressure liquid thin film disappears, the sliding surfaces 14a to 14c, 33a to 33c between the leg 14 and the guide 33 are provided.
The gap between them changes into mere play, and this play is
3 allows the lateral displacement of the guide plate 12 with respect to the guide plate 12. However, the protrusion 20 on the side surface 14b side of the leg portion 14 abuts against the side surface 33b of the guide portion 33, so that further displacement of the slider 13 in the lateral direction is prevented. Therefore, the side surface 1 of the leg portion 14 and the guide portion 33
A gap is secured between 4b and 33b.

When the static pressure liquid thin film disappears, the sliding surfaces 14a to 14c, 33a to 33c between the leg 14 and the guide 33 are provided.
The gap between them changes into mere play, and this play is
3 is allowed to tilt with respect to the guide plate 12. However, the protrusion 20 on the lower surface 14c side of the leg portion 14 is provided on the lower surface 33c of the guide portion 33, and the protrusion 20 on the upper surface 14a side.
Abuts against the upper surface 33a of the guide portion 33, thereby preventing the slider 13 from further tilting. Accordingly, a gap is secured between the upper surface 14a, 33a of the leg portion 14 and the guide portion 33 and between the lower surfaces 14c, 33c.

When the pressurized water is supplied to the static pressure pocket 16 at the next dressing of the grinding wheel 101, the leg 1
4 and guide surface 33 between sliding surfaces 14a to 14c, 33a to
Pressurized water enters the gap secured between 33c. Therefore, as described above, the sliding surfaces 14a to 14c, 33a to
A static pressure liquid thin film is formed between 33c, and the slider 13 floats on the guide plate 12. Slider 13
Is floating with respect to the guide plate 12, and the protrusion 2
0 is released from the state of contact with the guide portion 33 and does not slide on the guide portion 33 even when the slider 13 rotates (tilt the dressing wheel 32). That is, the protruding portion 20 is set to a height (amount of protrusion from each of the surfaces 14a to 14c) such that the protruding portion 20 is separated from the abutting state on the surfaces 33a to 33c of the guide portion 33 when the hydrostatic liquid thin film is formed. Have been.

The present embodiment having the above configuration has the following effects. (1) Sliding surfaces 14a to 14 between leg 14 and guide 33
When the static pressure liquid thin film is not formed between c, 33a to 33c, a gap is ensured by the protrusion 20 on the leg 14 abutting against the guide 33. Therefore, the pressurized water supplied to the static pressure pocket 16 when the grinding wheel 101 is dressed next time easily slides on the sliding surfaces 14a to 14c and 33a.
~ 33c. As a result, the static pressure liquid thin film is reliably and promptly formed, and the low friction sliding between the guide plate 12 and the slider 13 and the improvement in wear resistance by the static pressure receiving structure are favorably achieved.

(2) The problem when water was used as the pressurized fluid could be solved as described in (1) above. Therefore, in the present embodiment, water is used as the pressurized fluid, and it is not necessary to provide a closed circuit for circulation like oil, because of its availability and easy handling. This led to simplification of the static pressure receiving structure, and could be applied to a dresser for a grinding wheel at low cost.

(3) The protruding portions 20 have the sliding surfaces 14a to 14
c, when the hydrostatic thin film is formed between 33a-33c,
The guide 33 is released from the state of contact with the surfaces 33a to 33c. Therefore, the protruding portion 20 is not directly slidably contacted with the guide portion 33 even by the rotation of the slider 13, so that the wear and damage thereof can be prevented. as a result,
The above-described effect (1) can be achieved for a long time.

(4) The tip of the projection 20 has a convex spherical shape. Therefore, for example, even if the rotation of the slider 13 is started at the same time as the supply of the pressurized water, that is, even if the rotation of the slider 13 is started in a state where the hydrostatic liquid thin film is not sufficiently formed, the protrusion is formed. Each surface 33a-3 of the part 20
3c can be prevented, and the sliding movement of the slider 13 can be made smooth. Further, in this case, the protrusions 2 due to sliding with the guide plate 12 are formed.
0 wear damage can be reduced.

(5) The projecting portion 20 is provided on each surface 14 of the leg 14.
a to 14c are arranged at intervals in the sliding direction between the guide plate 12 and the slider 13.
Therefore, when the static pressure liquid thin film is not formed, the slider 1
3 is stable with respect to the guide plate 12, and a gap can be reliably secured between the sliding surfaces 14a to 14c and 33a to 33c.

(Second Embodiment) In this embodiment,
Except that the configuration of the protrusion 20 is omitted from the first embodiment, the configuration is the same as that of FIGS. 1 to 4. Also,
As shown in FIG. 5, a switching valve 41 is disposed on the discharge line 21, and the switching valve 41 has an air compressor 4.
2 are connected. The switching valve 41 is connected to the static pressure pocket 16.
The water pump 18 or the air compressor 42 is alternatively connected to the discharge port 17. The air compressor 42 can supply pressurized air to the static pressure pocket 16 in a state selected by the switching valve 41. The control computer 43 controls the switching valve 41, the water pump 18, and the air compressor 42. The static pressure pocket 16, the discharge port 17, the discharge conduit 21, the control computer 43, the switching valve 41, and the air compressor 42 constitute a pressurized gas supply unit.

For example, at the next dressing of the grinding wheel 101, the control computer 43 switches the switching valve 41, and the air compressor 42 is selected for the discharge port 17. In this state, the control computer 43 drives the air compressor 42 for a predetermined time, and pressurized air is supplied to the static pressure pocket 16. The air is more likely to enter the gap than water, and if pressurized air can enter between the sliding surfaces 14a to 14c, 33a to 33c, the pressure causes the gap between the sliding surfaces 14a to 14c, 33a to 33c to be increased. Can be spread.

After a predetermined time has elapsed, the control computer 43 stops driving the air compressor 42 and switches the switching valve 41 to select the water pump 18 for the discharge port 17. The control computer 43
The water pump 18 is driven to supply pressurized water to the static pressure pocket 16. Therefore, the pressurized water is applied to the sliding surfaces 14a to 14c and 33a which are spread by the supply of the pressurized air.
３３33c to form a static pressure liquid thin film.

It should be noted that there is a slight time difference between when the driving of the air compressor 42 is stopped and when the pressurized water is supplied to the static pressure pocket 16 by the water pump 18.
However, the pressurized air remaining in the static pressure pocket 16 and the discharge pipe 21 causes the sliding surface 14a to compensate for the time difference.
To 14c, 33a to 33c, and the sliding surfaces 14a to 14c, 33a to 3c spread by pressurized air until the pressurized water is supplied to the static pressure pocket 16.
The gap between 3c does not become so narrow that the pressurized water cannot enter.

The present embodiment having the above configuration has the following effects. (1) Water has a higher surface tension than oil. Therefore, when the static pressure liquid thin film is not formed, the guide plate 12 and the slider 13 are in a state of being adsorbed by the surface tension of the residual water. However, when the grinding wheel 101 is dressed next time, pressurized water is supplied after the gap between the sliding surfaces 14a to 14c and 33a to 33c is widened by pressurized air which easily enters the gap. ing. Therefore, the pressurized water can be easily applied to the sliding surfaces 14a to 14c,
It can enter between 33a-33c. as a result,
The static pressure liquid thin film is reliably and promptly formed, and the low friction sliding between the guide plate 12 and the slider 13 and the improvement of wear resistance by the static pressure receiving structure are favorably achieved.

(2) Sliding surfaces 14a to 14c, 33a to 3
Part of the pressurized liquid supply means (16, 17, 21) for supplying pressurized water between 3c constitutes pressurized gas supply means. Therefore, as compared with the case where the pressurized gas supply means is constituted by a dedicated circuit, the static pressure receiving structure can be simplified, and it can be applied to a dresser for a grinding wheel at low cost.

The present invention can be practiced in the following modes without departing from the spirit of the present invention. In the first embodiment, a liquid such as oil other than water or a gas such as air other than liquid is used as the pressurized fluid.

In the first embodiment, the protrusion 20
Is provided on each of the surfaces 33 a to 33 c of the guide portion 33. Alternatively, the protruding portions 20 are provided on the respective surfaces 14 a to 14 c and 33 a to 33 c of the leg portion 14 and the guide portion 33.

In the first embodiment, the protrusion 20
Shall be made of synthetic rubber. In the second embodiment, oil other than water is used as the pressurized liquid. In the second embodiment, the pressurized gas supply means is a circuit independent of the pressurized liquid supply means. That is, a dedicated static pressure pocket for pressurized air is provided on each of the surfaces 14a to 14c of the leg 14, and the air compressor 42 is connected to the static pressure pocket via a dedicated discharge pipe.

In the first or second embodiment, the pressurized water used for forming the hydrostatic liquid thin film is collected and supplied to the hydrostatic pocket 16 again. In each of the above embodiments, a rust inhibitor, an antifreezing agent, and the like are added to water.

The present invention is embodied in a static pressure receiving structure applied to a processing machine other than a grinding wheel dresser. For example, the present invention is embodied in a static pressure receiving structure of a reciprocating table that supports a workpiece to be processed. Further, the present invention is not limited to the static pressure receiving structure of the processing machine, and does not depart from the gist of the present invention even if it is embodied in the static pressure receiving structure of any sliding portion.

Next, the technical idea that can be grasped from the embodiment will be described below. The static pressure receiver according to any one of claims 1 to 3, wherein the tip of the projecting portion 20 is formed into a convex curved surface. Construction.

In this way, even if the sliding between the first member 12 and the second member 13 is started in a state where the hydrostatic thin film is not sufficiently formed, the sliding surface of the projecting portion 20 is formed. 33
It is possible to prevent corner contact with a to 33c.

[0042]

According to the present invention having the above-described structure, for example, even when water is used as the pressurized fluid, direct sliding between the first member and the second member can be prevented. The low friction sliding between the first member and the second member and the improvement in wear resistance due to the pressure receiving structure are favorably exhibited.

[Brief description of the drawings]

FIG. 1 is a front view of a dresser for a grinding wheel.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a cutaway view of a slider.

FIG. 4 is a view for explaining a dressing of a grinding wheel by a dresser for a grinding wheel.

FIG. 5 is a view showing a second embodiment.

[Explanation of symbols]

12: a guide plate as a first member, 13: a slider as a second member, 14a to 14c: a sliding surface on the slider side, 20: a protrusion, 33a to 33c: a sliding surface on the guide plate side.

Claims (4)

[Claims] 1. A static pressure receiving structure for supplying a pressurized fluid between sliding surfaces of a first member and a second member in a sliding relationship to form a hydrostatic fluid thin film, wherein the first member or the first member At least one sliding surface of the two members is provided with a protruding portion protruding toward the other sliding surface. When the hydrostatic thin film is not formed, the protruding portion abuts on the other sliding surface, so that A static pressure receiving structure configured to secure a gap between the sliding surfaces. 2. The static pressure receiver according to claim 1, wherein the protruding portion is set to such a height that when the hydrostatic fluid thin film is formed, the protruding portion is separated from a state of abutting against the other sliding surface. Construction. 3. The static pressure receiving structure according to claim 1, wherein the pressurized fluid is a liquid. 4. A static pressure receiving structure for supplying a pressurized liquid between sliding surfaces of a first member and a second member in a sliding relationship to form a hydrostatic thin film, wherein the first member and the first member A pressurized gas supply means for supplying a pressurized gas between sliding surfaces of the two members is provided, and when a hydrostatic liquid thin film is formed between the sliding surfaces, the pressurized gas is supplied by the pressurized gas supply means. Thus, a static pressure receiving structure configured to secure a gap between the sliding surfaces to facilitate the entry of the pressurized liquid.