JP2000346072A - Liquid hydrostatic bearing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To use one hydrostatic bearing device with variable rotation speed between a low speed rotation range and a high speed rotation range. In a low-speed rotation range, lubricating oil is supplied to a static pressure pocket (11) of a bearing main body (3) in a pressurized state by a pump (P2) in order to use an oil tank (27) side. Water tank 3 at high speed
To use one side, water is supplied by the pump P1. The water mixed in the oil tank 27 is removed by the drain valve 55, and the lubricating oil mixed in the water tank 31 is adsorbed and removed by the oil adsorbing filter K.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic bearing device which rotatably supports a rotating shaft by the pressure of liquid.

[0002]

2. Description of the Related Art Among hydrostatic bearing devices, a hydrostatic bearing device has a plurality of hydrostatic pockets 11 formed on an inner surface of a cylindrical bearing main body 3 as shown in FIG. The pump P is operated, and the supply port 1 of the static pressure pocket 11 is
By supplying the lubricating oil from the bearing 3 in a pressurized state, the rotating shaft 5 inserted into the bearing body 3 is rotatably supported by the pressure of the lubricating oil in the static pressure pocket 11. Such a hydrostatic bearing device 63 has a high rotation accuracy and an effect of absorbing (damping) fine vibrations by lubricating oil. Therefore, especially when a heavy tool is mounted on a spindle of a grinding machine and used. It is used for applications with large loads and vibrations.

[0003] In such a hydrostatic bearing device 63, the higher the viscosity of the lubricating oil, the greater the absorption of microvibrations, and thus it is suitable for use in a low-speed rotation region where rotation is not stable.
However, when a lubricating oil having a high viscosity is used, the rotational resistance is large. Therefore, when the rotational speed of the rotary shaft 5 is increased, the power loss increases, and the amount of generated heat increases, and the accuracy and durability of the device deteriorate. .

On the other hand, when a device used in a high-speed rotation range, for example, when a small tool is mounted on a general-purpose machining center and used, water is used instead of lubricating oil. Power loss and heat generation can be suppressed because of the small rotational resistance. However, if the rotation speed is reduced by an apparatus using water, the micro vibration cannot be sufficiently absorbed.

For this reason, a device using lubricating oil is used in a low-speed rotation region where the shaft peripheral speed is about 20 m / sec, and a device using water is used in a high-speed rotation region where the shaft peripheral speed exceeds 50 m / sec. It is necessary to use a plurality of hydrostatic bearing devices in accordance with the required rotational speed.

[0006]

However, if a plurality of hydrostatic bearing devices are selectively used in accordance with the rotational speeds as described above, the cost increases due to an increase in factory equipment. There is a demand for a hydrostatic bearing device that can be used in the field.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide means capable of using a single hydrostatic bearing device while varying the number of rotations between a low speed rotation range and a high speed rotation range. Is to do.

[0008]

According to a first aspect of the present invention, a liquid is supplied in a pressurized state to a static pressure pocket formed on an inner surface of a bearing body, and the liquid is inserted through the bearing body and the surface is supplied to the static pressure pocket. A liquid hydrostatic bearing device for rotatably supporting a viewed rotating shaft by the pressure of said liquid, comprising a supply mechanism for selectively supplying a plurality of types of liquids having different viscosities. It is a bearing device.

According to the first aspect of the present invention, since a supply mechanism for selectively supplying a plurality of types of liquids having different viscosities is provided, the number of rotations of one apparatus can be varied between a low-speed rotation range and a high-speed rotation range. Can be used. That is, in a low-speed rotation region, a buffer having a high viscosity can be obtained by using a liquid having a high viscosity, and in a high-speed rotation region, a liquid having a low viscosity can be used to suppress power loss and heat generation.

According to a second aspect of the present invention, there is provided the hydrostatic bearing device according to the first aspect of the present invention, further comprising a plurality of tanks for individually storing the plurality of types of liquids, and a liquid having a low specific gravity among the plurality of tanks. The hydrostatic bearing device is characterized in that an inclined bottom surface is provided in the tank to be accommodated, and a discharge port is provided near a lower portion of the bottom surface.

According to the second aspect of the present invention, when switching the supply of a plurality of types of liquids, even if a liquid having a high specific gravity is mixed with a liquid having a low specific gravity, the liquid having a high specific gravity is concentrated on a lower portion of the bottom surface. Therefore, the liquid having a high specific gravity can be easily removed by using the discharge port, so that a mixture of a plurality of types of liquids can be prevented.

According to a third aspect of the present invention, in the liquid hydrostatic bearing device according to the first or second aspect of the present invention, there are provided a plurality of tanks for individually storing the plurality of types of liquids, and a lubricating oil among the plurality of tanks is provided. A liquid hydrostatic bearing device characterized in that an oil-adsorbing filter is interposed in a path between a tank in which a liquid other than the liquid is to be stored and the static pressure pocket.

In the third aspect of the present invention, when lubricating oil and a liquid other than the lubricating oil are used, when the two are switched, the lubricating oil mixed into the liquid other than the lubricating oil is filtered by an oil-absorbing filter. Adsorbed and removed. Therefore, mixing of both can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. In FIG.
A hydrostatic bearing device 1 according to the present invention rotatably supports a rotating shaft 5 inserted in a bearing body 3 by supplying a liquid to the bearing body 3 in a pressurized state by a pump P1 or a pump P2. It is.

The bearing body 3 is cylindrical, and has a plurality of static pressure pockets 11 formed on the inner surface thereof.
1, a supply port 13 is provided, and a discharge port 15 is provided in a portion of the bearing body 3 where the static pressure pocket 11 is not formed. A drive shaft of a motor (not shown) is connected to the rotation shaft 5.

The conduit 21 communicating with the supply port 13 is connected to the discharge side of the three-way valve 25 via a filter F for filtering foreign matter, and one conduit 33 connected to the supply side of the three-way valve 25. Is connected to the oil tank 27 via a pump P2, and the other pipe line 35 connected to the supply side of the three-way valve 25 is connected to the water tank 31 via an oil-adsorbing filter K. As the filter material of the oil-adsorbing filter K, for example, a filter material in which a porous or fibrous base material is impregnated with a lipophilic / hydrophobic chemical agent is used.

The opening 35a at the lower end of the conduit 35 is arranged at a position sufficiently lower than the level of the water stored in the water tank 31. In addition, a rust inhibitor is mixed in the water used in the present embodiment.

Pipe line 4 communicating with outlet 15 of bearing body 3
1 is connected to the supply side of the three-way valve 45,
The one line 47 connected to the discharge side of the oil tank 27
And the other pipe 49 is connected to the water tank 31. Relief valves 51 and 53 for setting pressure are connected to the discharge sides of the pumps P1 and P2, respectively.

The bottom surface 27a of the oil tank 27 is inclined so that the right side in the figure becomes lower, and a drain valve 55 composed of a manual open / close valve is provided near the lowest part of the bottom surface 27a, that is, the right end in the figure. A drain tank 57 is disposed on the discharge side of the drain valve 55.

The operation of the hydrostatic bearing device 1 according to the present embodiment configured as described above will be described. First, when the shaft peripheral speed is used in a low-speed rotation range of about 20 m / sec, the pipes 33 and 47 are connected to the bearing body 3 by operating the three-way valves 25 and 45 to use the oil tank 27 side. State and pump P
Start 2 to supply lubricating oil. In this manner, the oil in the oil tank 27 is supplied to the static pressure pocket 11 of the bearing body 3 in a pressurized state set by the relief valve 53 at a pressure (for example, 50 kPa). It receives pressure and is rotatably supported while floating from the inner surface of the bearing main body 3, and is driven by the driving force of a motor (not shown).

Next, when the shaft peripheral speed is 50 m / sec to 100 m / sec.
When the pump P1 is used in a high-speed rotation range of about m / sec, the three-way valves 25 and 45 are operated to connect the pipes 35 and 49 to the bearing body 3 so that the water tank 31 is used. Start up and supply water. In this manner, the water in the water tank 31 is maintained at the pressure (for example, 1) set by the relief valve 51.
Under the pressurized state of 00 kPa).
1, the rotating shaft 5 receives uniform pressure from the surroundings, and is rotatably supported while floating above the inner surface of the bearing body 3, and is driven by a driving force of a motor (not shown). In this manner, one hydrostatic bearing device 1 is used with the number of revolutions varied between the low-speed rotation range and the high-speed rotation range.

At the time of this switching, a small amount of water or lubricating oil remaining in the static pressure pocket 11 and the pipelines 21 and 41 is mixed into the other tanks 27 and 31, respectively.
In the oil tank 27, the drain valve 55 is provided near the lowest end of the bottom surface 27a in the drawing, so that water having a higher specific gravity than lubricating oil concentrates on a lower portion of the bottom surface 27a. . Therefore, this water can be easily removed by opening the drain valve 55 appropriately.

Further, since the oil adsorbing filter K is interposed in the pipe 35 between the bearing body 3 and the water tank 31 and the pump P1, the lubricating oil mixed in the water is adsorbed by the oil adsorbing filter K. Removed. Therefore, even when the supply of water and the lubricating oil is switched and used, mixing of the two can be prevented. The oil-adsorbing filter K may be provided on the water tank 31 side with respect to the pump P1.

Particularly, in the present embodiment, the opening 35a at the lower end of the conduit 35 is located at a position sufficiently lower than the level of the water contained in the water tank 31, so that the lubricating oil mixed in the water is Because it floats near, it is difficult to be sucked through the opening 35a. Therefore, the oil-adsorbing filter K only needs to filter water having a low concentration of lubricating oil, so that the filtering performance of the filter K can be maintained for a long period of time, while lubricating the water supplied to the bearing body 3. Oil contamination can be minimized.

In this embodiment, the lubricating oil and the water are used by switching. However, the present invention is not limited to such a mode. For example, two kinds of lubricating oils having different viscosities are used. It is also possible to adopt a configuration, and it is also possible to adopt a configuration using three or more types of lubricating oils.

In the present embodiment, the three-way valves 25 and 45 are manually operated to switch the supply of the two types of liquids. However, instead of such a configuration, for example, the three-way valves 25 and 4 may be used.
While an actuator for operating the rotary shaft 5 is provided, the number of rotations of the rotary shaft 5 is detected based on an input of a power supply system to a rotation sensor and a motor, and the three-way valves 25 and 4 are detected according to the detected number of rotations.
5 may be configured to control the opening and closing operation, and such a configuration is also included in the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a hydrostatic bearing device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional hydrostatic bearing device.

[Explanation of symbols]

1,63 hydrostatic bearing device, 3 bearing body, 5 rotating shaft,
11 static pressure pocket, 13 supply port, 15 discharge port, 2
5, 45 three-way valve, 27, 67 oil tank, 31 water tank, 51, 53 relief valve, 55 drain valve,
K Oil-absorbing filter, P, P1, P2 pump.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Sato 3-2, Shinbocho, Chigusa-ku, Nagoya-shi, Aichi F-term (reference) 3J102 AA02 BA03 BA17 CA09 CA36 EA03 EA06 EA09 EA22 EA30 GA07

Claims (3)

[Claims] A liquid is supplied under pressure to a static pressure pocket formed on an inner surface of a bearing body, and a rotating shaft inserted through the bearing body and whose surface is viewed through the static pressure pocket is applied to the pressure of the liquid. 1. A hydrostatic bearing device rotatably supported by a liquid hydrostatic bearing device, comprising: a supply mechanism for selectively supplying a plurality of types of liquids having different viscosities. 2. The hydrostatic bearing device according to claim 1, further comprising: a plurality of tanks for individually storing the plurality of types of liquids, wherein a tank for storing a liquid having a low specific gravity among the plurality of tanks is provided. A hydrostatic bearing device comprising: an inclined bottom surface; and a discharge port provided near a lower portion of the bottom surface. 3. The hydrostatic bearing device according to claim 1, further comprising: a plurality of tanks for individually storing the plurality of types of liquids, wherein the plurality of tanks store liquids other than lubricating oil. A liquid hydrostatic bearing device, wherein an oil-adsorbing filter is interposed in a path between a tank to be produced and the static pressure pocket.