JP2015040587A - Hydrostatic bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrostatic bearing device enabled by a simple construction to stop a movable body at a desired position on a guide body.SOLUTION: A movable body 13 is movably supported on a guide body 12 through a fluid over-flowing from the pockets 14A and 14B of a hydrostatic bearing. At a position within the moving range of the movable body 13, the supply mode of the fluid pressure upon the oil pocket 14A is changed by a changeover valve 24 thereby to retrain the movement of the movable body 13.

Description

  The present invention relates to a hydrostatic bearing device using a hydrostatic bearing that is applied, for example, when a machining table is moved and guided in a machine tool or the like.

  Conventionally, as this type of hydrostatic bearing device, for example, a configuration as disclosed in Patent Document 1 has been proposed. In this conventional configuration, the volume of the pocket of the hydrostatic bearing is increased or decreased to change the pressure in the pocket, and the position or posture of the moving body with respect to the guide body is corrected.

JP 2009-299726 A

However, this conventional hydrostatic bearing device does not have a function of holding the moving body at a required position with a simple configuration.
The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a hydrostatic bearing device that can hold a moving body at a predetermined position on a guide body with a simple configuration.

  In order to achieve the above object, the hydrostatic bearing device is a hydrostatic bearing device in which a moving body is movably supported on a guide body via a hydrostatic bearing, at a position within a moving range of the moving body. A switching means for switching the supply mode of the fluid pressure to the pressure bearing is provided to restrict the movement of the moving body.

  Therefore, in this hydrostatic bearing device, when the moving body is moved to a required position and stopped at that position, the supply mode of the fluid pressure to the hydrostatic bearing is switched by the switching valve, and the moving body is moved. Be bound. Therefore, the configuration is simple, and the moving body can be accurately held at a predetermined position on the guide body and held.

  According to the above-mentioned hydrostatic bearing device, the moving body can be held stationary at a predetermined position on the guide body with a simple configuration.

Sectional drawing which shows the hydrostatic bearing apparatus using the hydrostatic bearing of 1st Embodiment. Sectional drawing which shows the hydrostatic bearing apparatus using the hydrostatic bearing of 2nd Embodiment. Sectional drawing which shows the hydrostatic bearing apparatus using the hydrostatic bearing of 3rd Embodiment.

(First embodiment)
A first embodiment embodied in a hydrostatic bearing device for a machining table in a machine tool will be described below with reference to FIG.

  As shown in FIG. 1, a guide body 12 is arranged on the machine base 11 so as to extend in a direction perpendicular to the drawing sheet along one axis. On the guide body 12, the moving body 13 constituting the processing table moves in a non-contact state through the oil film overflowing from the pockets 14A and 14B of the plurality of hydrostatic bearings on the guide body 12 side in the recess 131 on the lower surface thereof. Supported as possible. A linear motor 15 is disposed between the upper surface of the guide body 12 and the lower surface of the moving body 13 as a driving means for moving the moving body 13. The linear motor 15 includes a stator 151 made of a coil provided on the guide body 12 side and a mover 152 made of a magnet provided on the moving body 13 side.

  Of the plurality of oil pockets 14 </ b> A and 14 </ b> B, the pair of oil pockets 14 </ b> A is disposed between the upper surface of the guide body 12 and the lower surface of the moving body 13 on both sides of the linear motor 15. Further, the remaining pair of oil pockets 14 </ b> B is disposed between the outer surfaces on both sides of the guide body 12 and the inner surfaces on both sides of the moving body 13.

  A pair of oil discharge grooves 16 are formed on the upper surface of the guide body 12 between the stator 151 of the linear motor 15 and the pair of oil pockets 14A. When oil is used as the static pressure fluid in the oil pockets 14A and 14B, the oil overflowing from the oil pocket 14A is discharged through the oil discharge groove 16. Thereby, the penetration | invasion of the oil to the linear motor 15 side is suppressed.

  A pair of oil pockets 14 </ b> B disposed between the outer surface on both sides of the guide body 12 and the inner surfaces on both sides of the moving body 13 is supplied with oil as a static pressure fluid from a supply source (not shown) by a pump 17. 18 is supplied. Further, oil is supplied to the pair of oil pockets 14 </ b> A disposed between the upper surface of the guide body 12 and the lower surface of the moving body 13 through the second supply path 19 by the operation of the pump 17. Throttle valves 20 and 21 are connected in both supply paths 18 and 19.

  A return path 22 having a check valve 23 is connected in parallel to the throttle valve 21 in the second supply path 19. In the second supply path 19, the fluid pressure supply mode for the oil pocket 14 </ b> A is switched to a position within the moving range of the moving body 13 at a position closer to the pump 17 than the throttle valve 21 to restrain the movement of the moving body 13. A switching valve 24 as switching means is connected at the two ports. An oil tank 25 is connected to the other port of the switching valve 24.

Next, the operation of the hydrostatic bearing device configured as described above will be described.
In the state shown in FIG. 1, the switching valve 24 in the second supply path 19 is switched to one of the two switching positions 241 and 241, and the second supply path 19 is opened. In this state, when the pump 17 is operated, oil is supplied as a static pressure fluid from the oil tank 25 to the oil pocket 14 </ b> B via the first supply path 18 and also to the oil pocket via the second supply path 19. 14A. Thereby, the movable body 13 carrying a workpiece (not shown) is supported on the guide body 12 so as to be movable in a non-contact state via the oil film overflowing from the oil pockets 14A and 14B.

  When the linear motor 15 is energized while the movable body 13 is supported, the movable body 13 is reciprocated within a predetermined movement range, and the mounted workpiece is subjected to processing such as grinding.

  When the switching valve 24 in the second supply path 19 is switched to the other position 242 in a state where the energization operation of the linear motor 15 is stopped and the movement of the linear motor 15 is stopped, the following state is obtained. . That is, the second supply path 19 between the pump 17 and one oil pocket 14 </ b> A is closed, and the oil pocket 14 </ b> A is connected to the oil tank 25 via the second supply path 19 and the return path 22. As a result, the supply of oil to the oil pocket 14A is stopped, and the oil in the oil pocket 14A is returned to the oil tank 25 via the second supply path 19 and the return path 22.

  As a result, the moving body 13 is moved downward by its own weight, the lower surface of the moving body 13 is joined to the upper surface of the guide body 12, and the movement of the moving body 13 is restrained. At this time, oil is supplied to the other oil pocket 14B through the first supply path 18 by the operation of the pump 17, and the gap between the outer surface on both sides of the guide body 12 and the inner surface on both sides of the movable body 13 is not. It is kept in contact. Therefore, in this state, the workpiece on the moving body 13 can be subjected to high-precision machining on the stationary workpiece, such as drilling.

Therefore, according to this embodiment, the following effects can be obtained.
(1) In this embodiment, the movable body 13 is movably supported on the guide body 12 via the fluid overflowing from the pockets 14A and 14B of the hydrostatic bearing. A switching valve 24 that restricts the movement of the moving body 13 by switching the supply mode of the fluid pressure to the oil pocket 14A at a position within the moving range of the moving body 13 is provided.

  For this reason, in this hydrostatic bearing device, when the moving body 13 is moved to a predetermined position within the moving range and stopped at that position, the supply mode of the fluid pressure to the oil pocket 14A is switched by the switching valve 24. Thus, the movement of the moving body 13 is restricted. Therefore, the movable body 13 can be accurately stopped and held at a predetermined position on the guide body 12. Therefore, high-precision machining can be performed on the stationary workpiece on the moving body 13.

(2) Moreover, the configuration for that purpose is very simple because only the switching valve 24 and the like are provided in the hydraulic circuit.
(Second Embodiment)
Next, a second embodiment of the hydrostatic bearing device will be described with a focus on differences from the first embodiment.

  In the second embodiment, as shown in FIG. 2, a pair of guide bodies 12 having a substantially inverted L-shaped cross section are extended and arranged linearly on the machine base 11 at intervals. On the lower surface of the moving body 13, a pair of grooves 132 having a substantially inverted L-shaped cross section that can be engaged with each guide body 12 is formed. Oil pockets 14 </ b> A and 14 </ b> C are arranged on both upper and lower surfaces of each guide body 12 so as to face the inner surface of each groove portion 132 in the moving body 13. An oil pocket 14 </ b> B is arranged on the side surface of one guide body 12 so as to face the inner surface of one groove portion 132 in the moving body 13.

  On the side opposite to the oil pocket 14B, a linear motor 15 including a stator 151 and a moving element 152 is disposed between the side surface of the other guiding body 12 and the inner surface of the other groove 132 of the moving body 13. Yes.

  And with respect to the upper oil pocket 14A of the oil pockets 14A, 14C provided between the upper and lower surfaces of each guide body 12 and the opposing inner surface of each groove portion 132 of the movable body 13, the first embodiment and A first supply path 18 having a similar oil supply configuration is connected, and a second supply path 19 is connected to the lower oil pocket 14C. Further, the oil pocket 14 </ b> B provided between the side surface of the guide body 12 and the inner surface of the groove portion 132 of the moving body 13 is connected to the first supply path 18.

  Therefore, in this embodiment, when the moving body 13 is linearly moved along the guide body 12 and stopped at a predetermined position by the operation of the linear motor 15, the lower oil is changed by switching the switching valve 24. The supply of oil to the pocket 14C is stopped. At this time, since oil is supplied to the upper oil pocket 14A, the inner lower surface of the groove portion 132 of the movable body 13 is pressed against the lower surface of the guide body 12 by the pressure of the oil, and the movement of the movable body 13 is performed. Is restrained.

Therefore, according to the second embodiment, in addition to the effects described in (1) and (2) in the first embodiment, the following effects can be obtained.
(3) In this embodiment, oil pockets 14A and 14C are provided at positions opposite to each other of the linearly extending guide body 12, and the switching valve 24 causes the static pressure on the oil pocket 14C on one side. The supply of fluid is stopped. For this reason, when the supply of the static pressure fluid to the one side oil pocket 14C is stopped, the moving body 13 moves toward the one side oil pocket 14C by the pressure of the static pressure fluid supplied to the other side oil pocket 14A. The movement of the moving body 13 is restrained by being pressed. Therefore, the movable body 13 can be accurately stopped at a predetermined position on the guide body 12.

(Third embodiment)
Next, a third embodiment of the hydrostatic bearing device will be described with a focus on differences from the first embodiment.

  In the third embodiment, as shown in FIG. 3, a cylindrical first guide body 12 </ b> A and a columnar second guide body 12 </ b> B are arranged concentrically on the machine base 11. On the first guide body 12A, the disc-shaped moving body 13 constituting the rotary table is fitted and supported on the second guide body 12B so as to be rotatable around one axis at a boss portion 133 as an axis of the lower surface. Yes. An annular oil pocket 14 </ b> A is disposed on the upper surface of the first guide body 12 </ b> A so as to face the lower surface, which is the plane of the moving body 13. An annular oil pocket 14 </ b> B is disposed on the outer peripheral surface of the second guide body 12 </ b> B so as to face the inner peripheral surface of the boss portion 133 of the moving body 13.

  Inside the oil pocket 14A, between the upper surface of the first guide body 12A and the lower surface of the moving body 13, a linear motor 15 including a stator 151 and a moving element 152 is arranged in an annular shape.

  A second oil supply configuration similar to that of the first embodiment is applied to an annular oil pocket 14B provided on the outer peripheral surface of the second guide body 12B so as to face the boss portion 133 of the moving body 13. 1 is connected to the supply path 18. A second supply path 19 is connected to an annular oil pocket 14 </ b> A provided between the upper surface of the first guide body 12 </ b> A and the lower surface of the moving body 13.

  Then, when the linear motor 15 is energized in a state where oil is supplied to both the oil pockets 14A and 14B, the moving body 13 is rotated about one axis. Further, when the switching valve 24 is switched in a state where the energization to the linear motor 15 is stopped, the oil supply to the oil pocket 14A is stopped. Therefore, the moving body 13 is stopped in a state where the rotation axis of the moving body 13 coincides with the axis of the second guide body 12B.

Therefore, in the third embodiment, the following effects can be obtained.
(4) The movable body 13 can be smoothly and highly accurately rotated through the hydrostatic bearing to perform a process such as cutting on the workpiece on the movable body 13. Then, by switching the switching valve 24, the movable body 13 can be stopped at a required rotational angle position, and drilling or the like can be performed on the stationary workpiece with high accuracy.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In the second embodiment, among the oil pockets 14A and 14C positioned above and below the guide body 12, the supply of the static pressure fluid to the upper oil pocket 14A is stopped.

  The configuration of each of the above embodiments is applied to a hydrostatic bearing device of a moving body different from the processing table of the machine tool, for example, a hydrostatic bearing device that supports the main shaft.

  DESCRIPTION OF SYMBOLS 12 ... Guide body, 12A ... 1st guide body, 12B ... 2nd guide body, 13 ... Moving body, 14A, 14B, 14C ... Oil pocket, 15 ... Linear motor as drive means, 17 ... Pump, 18 ... 1st Supply path, 19 ... second supply path, 24 ... switching valve as switching means, 241 ... position, 242 ... position.

Claims (5)

In the hydrostatic bearing device in which the movable body is movably supported on the guide body via the hydrostatic bearing,
A hydrostatic bearing device provided with a switching means for switching a supply mode of fluid pressure to the hydrostatic bearing so as to restrain movement of the moving body. 2. The hydrostatic bearing device according to claim 1, wherein an oil pocket is provided at a position on the opposite side of the linearly extending guide body, and the switching unit stops supplying the hydrostatic fluid to the one side pocket. 3. The hydrostatic bearing device according to claim 2, wherein the moving body is a table that moves linearly while supporting a workpiece. The moving body is rotated about one axis, and the oil pocket is provided in a portion facing the axis of the moving body and a portion facing the plane, and the switching means is on the side facing the plane. The hydrostatic bearing device according to claim 1, wherein the supply of hydrostatic fluid to the pockets is stopped. The hydrostatic bearing device according to claim 4, wherein the movable body is a rotary table that is rotated while supporting a workpiece.