JPH0452487Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a hydrostatic bearing device in which a bearing pocket, to which hydraulic pressure is supplied from outside, is provided between the outer circumferential surface of a spindle and the inner circumferential surface of a bearing member which rotatably supports the spindle.

[Conventional technology]

Conventionally, in the above-mentioned hydrostatic bearing devices, a contact member for sealing that is in constant contact with the spindle and the bearing member is provided in order to prevent oil from leaking out of the device from between the spindle and the bearing member. Alternatively, sealing pressurized air may be supplied into the end of the bearing member to create an air curtain.

[Problem that the invention attempts to solve]

Among conventional hydrostatic bearing devices, those equipped with a contact member for sealing are always in contact with the contact member and the spindle, so the rotation of the spindle can cause the contact member and the contact part of the spindle to generate heat. There was a problem that oil leakage occurred due to wear and tear. In addition, with air curtains, when the spindle stops, the sealing air is also stopped under pressure, which causes oil leakage, and this poses a problem, especially in hard-shaft hydrostatic bearings, which is so prone to oil leakage that it cannot be used. . This invention solves the above-mentioned problems and ensures that the spindle and sealing contact ring do not generate heat or wear out, and there is no oil leakage even when the spindle is stopped, and it is reliable for a long time. The purpose of this invention is to provide a hydrostatic bearing device that can seal oil.

[Means to solve the problem]

The present invention provides a hydrostatic bearing device in which a bearing pocket to which hydraulic pressure is supplied from the outside is provided between an outer circumferential surface of a spindle and an inner circumferential surface of a bearing member that rotatably supports the spindle. a small outer diameter portion and a large outer diameter portion are provided through a step, a sealing contact ring is fitted in the bearing member so as to be slidable in the axial direction, and a spring presses the contact ring against the step of the spindle. is supported on one end surface of the contact ring, and a pressurized air chamber is formed on the back side of the one end surface of the contact ring in the bearing member, and the small outer diameter of the spindle is A push rod that moves toward the outer diameter of the spindle is placed inside the bearing member on the large outer diameter side of the spindle.
The tip of the push rod is brought into contact with the other end surface of the contact ring.

[Effect]

Since the hydrostatic bearing device according to the present invention is configured as described above, when the spindle is stopped, the pump that supplies pressure oil to the bearing pocket and the device that supplies sealing pressure air to the pressure air chamber are also stopped. However, as shown in FIG. 1, since the contact ring is pressed against the stage of the spindle by the spring, oil does not leak to the outside from between the spindle and the bearing member. Also, while the spindle is rotating, as shown in Fig. 2, the push rod is moved toward the small diameter part of the spindle by the pressure oil sent to the bearing pocket side, and the contact ring is separated from the stage of the spindle. Wear and heat generation of the contact ring and spindle are prevented. While the spindle is rotating, sealing pressure air is supplied to the air chamber, and the pressure on the back side of the contact ring is higher than on one end surface of the contact ring, so that oil does not leak to the outside from between the spindle and the bearing member.

【Example】

Below, an example of this invention is shown in Figures 1 and 2.
This will be explained with reference to the figures. In Figures 1 and 2, 1 is a spindle, 2
is a substantially cylindrical bearing member that rotatably supports the spindle 1. The bearing member 2 is fitted and fixed to the stationary side member 3, and a plurality of bearing pockets 4 are provided at intervals in the circumferential direction at an axially intermediate portion of the inner circumferential surface.
is formed. A pressure oil supply groove 6 for supplying pressure oil to the bearing pocket 4 through a throttle 5 is formed in an annular shape on the outer peripheral surface of the bearing member 2. Pressure oil is supplied to the pressure oil supply groove 6 from a pump (not shown) when the spindle 1 rotates. A drain groove 18 for returning oil from the bearing pocket 3 to an oil tank (not shown)
A drain hole 7 is also formed in the bearing member 2. The spindle 1 is provided with a small outer diameter section 1b and a large outer diameter section 1c on the shaft end side via a step 1a. A sealing contact ring 8 is fitted into the small outer diameter portion 1b of the spindle 1 so as to be slidable in the axial direction. This contact ring 8 has a seal ring 9 on its outer periphery.
are fitted and fixed, and are fitted to the inner circumferential surface of the bearing member 2 via a seal ring 9 so as to be slidable in the axial direction. Note that the contact ring 8 is provided with a protruding portion 8a on the inner peripheral portion thereof, which abuts against the step 1a of the spindle 1. An end plate 10 is fixed to the end of the bearing member 2,
An annular projection 10a is formed on the inner end surface of the end plate 10, and recesses 10b are provided at a plurality of locations in the circumferential direction of the projection 10a. One end of a spring 11 is fitted and supported in these recesses 10b, the other end of the spring 11 is supported by one end surface of a contact ring 8, and the contact ring 8 is urged by the spring 11 toward the stage 1a of the spindle 1. has been done. A pressure air chamber 12 is provided on the back side of one end surface of the contact ring 8 of the bearing member 2.
is formed, and this air chamber 12 is connected to a sealing pressurized air supply device (not shown) through a sealing air supply hole 13 provided in the end plate 10. Inside the bearing member 2, cylinder holes 14 are formed at a plurality of locations in the circumferential direction of a portion corresponding to the large outer diameter portion 1c of the spindle 1, parallel to the axial direction of the spindle 1, and the bottom of the cylinder hole 14 is a small diameter pressure hole. It is connected to the pressure oil supply groove 6 through an oil supply hole 15, and a push rod 16 is slidably fitted into the cylinder hole 14. The push rod 16 is connected to the bearing member 2 and the large outer diameter portion 1 of the spindle 1.
The contact ring 8 extends parallel to the spindle 1 between the contact rings 1 and 1c, and its tip is in contact with the other end surface of the contact ring 8. Next, the operation of the hydrostatic bearing device configured as above will be explained. When the spindle 1 is stopped as shown in FIG. 1, the pump that supplies pressure oil to the bearing pocket 4 and the device that supplies sealing pressure air to the pressure air chamber 12 are also stopped. In this state, the spring 10
Since the protrusion 8a of the contact ring 8 is pressed against the step 1a of the spindle 1 by the spring force, oil does not leak to the outside from between the spindle 1 and the bearing member 2. When the spindle 1 is rotated, a pump and a sealing pressurized air supply device are driven. By driving the pump, pressure oil is supplied from the pressure oil supply groove 6 to the bearing pocket 4 through the throttle 5, and the spindle 1
An oil film is formed between the bearing member 2 and the bearing member 2, and the spindle 1 is supported by the bearing member 2 under hydrostatic pressure. As shown in FIG. 2, a part of the pressure oil supplied to the bearing member 2 is supplied from the pressure oil supply groove 6 to the cylinder hole 14 through the pressure oil supply hole 15, so that the push rod 16 is pushed into the spindle 1. The contact ring 8 is moved in the direction of the outer diameter portion 1b and moved in the same direction against the spring force of the spring 11, so that the contact ring 8 is separated from the step 1a of the spindle 1 and supported on the protrusion 10a of the end plate 10.
Further, by driving the pressurized air supply device, sealing pressure air is supplied from the air supply hole 13 to the pressure air chamber 13, and the pressure on the back side of the contact ring 8 is made higher than on the one end surface. The state shown in FIG. 2 continues while the spindle 1 is in operation, and when the spindle 1 is stopped, the pressure oil supply pump and pressurized air supply device are also stopped, returning to the state shown in FIG. 1 again. Therefore, in the hydrostatic bearing device of this embodiment, the contact ring 8 is pressed against the stage 1a of the spindle 1 by the spring 10 when the spindle 1 is stopped, and the contact ring 8 is pressed against the stage 1a of the spindle 1 when the spindle 1 is rotating. Although the ring 8 is separated from the stage 1a of the spindle 1, the pressure air chamber 1 on the back side of the contact ring 8
2, oil does not leak to the outside from between the spindle 1 and the bearing member 2. Then, in the rotating state of spindle 1,
Step 1a of spindle 1 and protrusion 8 of contact ring 8
a is spaced apart from each other, so that the step 1a and the protrusion 8a
does not wear out and does not generate heat due to wear. Although the above explanation has been made regarding only one end of the bearing member, leakage of oil from the other end of the bearing member is prevented or treated by conventionally known appropriate means.

[Effect of the idea]

As explained above, in the hydrostatic bearing device of this invention, when the spindle is stopped, the contact ring fitted in the bearing member so as to be slidable in the axial direction is pressed against the step of the spindle by the spring. When the spindle is rotating, the push rod is moved by the pressure oil supplied to the bearing pocket, and the contact ring is separated from the stage of the spindle. Since the pressure is high, oil will not leak to the outside from between the spindle and the bearing member, whether the spindle is stopped or rotating, and when the spindle is rotating, the contact ring will close to the spindle stage as described above. Since the contact ring and the spindle are spaced apart from each other, the contact ring and spindle do not wear out or generate heat, and this has the effect of ensuring reliable oil sealing over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing a hydrostatic bearing device according to an embodiment of this invention with the spindle stopped;
The figure is a longitudinal sectional side view of one end of the spindle in the operating state. DESCRIPTION OF SYMBOLS 1...Spindle, 1a...Step, 1b...Small outer diameter part, 1c...Large outer diameter part, 2...Bearing member, 4...
... Bearing pocket, 8 ... Contact ring, 10 ... End plate, 11 ... Spring, 12 ... Pressure air chamber,
13... Air supply hole, 14... Cylinder hole, 16
...Push stick.

Claims (1)

[Scope of utility model registration request] In a hydrostatic bearing device in which a bearing pocket to which hydraulic pressure is supplied from the outside is provided between the outer circumferential surface of a spindle and the inner circumferential surface of a bearing member that rotatably supports the spindle, the spindle is provided with a stage. a small outer diameter portion and a large outer diameter portion, a sealing contact ring is slidably fitted in the bearing member in the axial direction, and a spring that presses the contact ring against the step of the spindle is attached to the contact ring. A pusher is supported on one end surface of the ring, forms a pressurized air chamber on the back side of the one end surface of the contact ring in the bearing member, and is moved toward the outer diameter side of the spindle by hydraulic pressure sent to the bearing pocket side when the spindle rotates. A hydrostatic bearing device characterized in that a rod is disposed within the bearing member on the side of the large outer diameter portion of the spindle, and the tip of the push rod is brought into contact with the other end surface of a contact ring.