A liquid hydrostatic bearing assembly

Abstract

This invention discloses a hydrostatic bearing assembly, comprising an adjustable oil chamber device, an oil inlet seat, and a bearing body. The oil inlet seat is mounted on the outer surface of the bearing body, and the adjustable oil chamber device is connected to the oil inlet seat. The adjustable oil chamber device includes a valve body, a slide valve, a piezoelectric ceramic, an upper cover plate assembly, and an oil chamber control block. The valve body has a first vertical cavity, and the slide valve and piezoelectric ceramic are installed in the first vertical cavity. One end of the piezoelectric ceramic is connected to the upper cover plate assembly, and the other end of the piezoelectric ceramic is connected to the upper end of the slide valve. The lower end of the slide valve is connected to the oil chamber control block. The oil chamber control block is a shallow oil chamber control block. This technical solution allows for active control of the oil chamber depth to obtain dynamic oil film force, thereby improving the rotational accuracy of the hydrostatic bearing.

Description

Technical Field

[0001] This invention relates to the field of hydrostatic bearing technology, and particularly to a liquid hydrostatic bearing assembly. Background Technology

[0002] Liquid hydrostatic bearings are a new type of oil film bearing developed based on hydrostatic bearings and hydrostatic bearings. They combine the advantages of both hydrostatic bearings and hydrostatic bearings.

[0003] When the spindle is stationary or its speed is below a certain critical value, the pressure difference formed between the hydrostatic chambers by the pressurized oil lifts the spindle and subject it to a certain external load, so that the bearing is in a state of full fluid friction. When the spindle speed increases, the hydrostatic bearing has both hydrodynamic and hydrostatic effects, which improves the bearing's load-bearing capacity.

[0004] Shallow-cavity hydrostatic radial bearings are designed to fully utilize the hydrostatic effect of oil-cavity bearings by shallowing the deep hydrostatic cavity, bringing the cavity depth to the same order of magnitude as the bearing clearance. This bearing utilizes pressurized oil passing through a shallow cavity and an axial sealing surface, forming a stepped structure parallel to the shaft's rotation direction, to generate hydrostatic load. When the shaft rotates, it utilizes the stepped structure perpendicular to the rotation direction, formed by the shallow cavity and circumferential sealing surface. The shallow cavity can also function as a throttle, thus eliminating the need for a separate throttle. This bearing offers advantages such as high rigidity, high precision, good stability, good vibration resistance, simple structure, and low oil pump power consumption. However, a method has not yet been proposed to improve the rotational accuracy of hydrostatic bearings by directly controlling the cavity depth to obtain dynamic oil film force. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a shallow oil cavity hydrostatic radial bearing assembly with controllable oil cavity, the specific technical solution of which is as follows:

[0006] A liquid hydrostatic bearing assembly includes an adjustable oil chamber device, an oil inlet seat, and a bearing body. The oil inlet seat is installed on the outer surface of the bearing body, and the adjustable oil chamber device is connected to the oil inlet seat. The adjustable oil chamber device includes a valve body, a slide valve, a piezoelectric ceramic, an upper cover plate assembly, and an oil chamber control block. The valve body has a first vertical cavity, and the slide valve and the piezoelectric ceramic are both installed in the first vertical cavity. One end of the piezoelectric ceramic is connected to the upper cover plate assembly, and the other end of the piezoelectric ceramic is connected to the upper end of the slide valve. The lower end of the slide valve is connected to the oil chamber control block. The oil chamber control block is a shallow oil chamber control block.

[0007] Preferably, the valve body also has a first horizontal through hole perpendicular to the first vertical cavity, and the oil inlet seat is provided with an oil inlet hole, the first horizontal through hole being connected to the oil inlet hole.

[0008] Preferably, the slide valve includes a head, an oil seal, a throttling orifice, and an oil outlet orifice. The oil seal, throttling orifice, and oil outlet orifice are all disposed within the slide valve. The slide valve also has a second vertical cavity. The oil seal is disposed within the second vertical cavity. The oil outlet end of the second vertical cavity is connected to the throttling orifice. The throttling orifice is connected to the oil outlet orifice. The oil outlet orifice is connected to the oil cavity control block.

[0009] Preferably, the slide valve is further provided with a second horizontal through hole perpendicular to the second vertical cavity, and the second horizontal through hole communicates with the first horizontal through hole.

[0010] Preferably, the upper cover plate assembly includes a fixing base and an upper cover plate, the piezoelectric ceramic is connected to the fixing base, and the upper cover plate is connected to the fixing base.

[0011] Preferably, the bearing assembly is further provided with a control device, the piezoelectric ceramic is provided with a power line, the upper cover plate is provided with a wire hole, and the power line passes through the wire hole and is connected to the power line.

[0012] Preferably, the upper cover plate assembly further includes a first fastening mechanism and a second fastening mechanism, wherein the upper cover plate and the fixing seat are fixed by the first fastening mechanism, and the valve body and the upper cover plate are fixed by the second fastening mechanism.

[0013] Preferably, the adjustable oil chamber device further includes a spring, which is fixedly connected to the lower end face of the head.

[0014] Preferably, the spring is a disc spring.

[0015] Preferably, there are multiple adjustable oil chamber devices and oil inlet seats, which are evenly distributed on the outer surface of the bearing body.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention obtains dynamic oil film force by directly controlling the change in oil cavity depth. By actively controlling the depth of the shallow and medium-shallow oil cavities in this component, the rotational accuracy of the hydrostatic bearing is improved. Specifically, piezoelectric ceramics directly participate in the control of the shallow oil cavity depth. When the hydrostatic bearing assembly supports the rotation of the spindle, if a rotational error is detected, the rotational error can be compensated by coordinating the adjustment of the depth of the four shallow oil cavities, thereby adjusting the magnitude of the oil film force, improving the spindle's rotational accuracy, and enabling the spindle to achieve optimal support performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the liquid hydrostatic bearing assembly of the present invention;

[0019] Figure 2This is a cross-sectional view of the oil chamber device and oil inlet seat in the present invention;

[0020] Figure 3 This is a partially enlarged view illustrating the depth of the oil cavity in this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 As shown, a hydrostatic bearing assembly with adjustable oil cavity depth includes an adjustable oil cavity device 100, an oil inlet seat 200, and a bearing body 300. The oil inlet seat 200 is fixedly connected to the bearing body 300, and the adjustable oil cavity device 100 is fixedly connected to the oil inlet seat 200. The number of adjustable oil cavity devices 100 and oil inlet seats 200 can be set according to the specific needs of the bearing assembly. In this embodiment, four adjustable oil cavity devices 100 and four oil inlet seats 200 are evenly distributed on the outer circumference of the bearing body 300. The oil inlet seat 200 has a central hole, through which the adjustable oil cavity device 100 passes and is fixedly connected to the oil inlet seat 200.

[0023] Furthermore, such as Figure 2 As shown, the adjustable oil chamber device 100 includes a valve body 1, a slide valve 2, a piezoelectric ceramic 3, an oil inlet seat 4, an upper cover plate assembly 5, and an oil chamber control block 7.

[0024] The valve body 1 is fixedly connected to the oil inlet seat 4; the valve body 1 has a first vertical cavity and a first horizontal through hole 12 that are perpendicular to each other. The slide valve 2 and the piezoelectric ceramic plate 3 are disposed in the first vertical cavity, and one end of the piezoelectric ceramic plate 3 is fixedly connected to the upper cover plate assembly 5 through the first vertical cavity. The other end of the piezoelectric ceramic plate 3 is fixedly connected to the upper end of the slide valve 2. The oil chamber control block 7 is fixedly connected to the lower end of the slide valve 2.

[0025] The above structural design allows the adjustable oil chamber device 100 to actively control the depth h of the oil chamber, thereby achieving intelligent dynamic adjustment of the oil film force according to the bearing operating conditions. Figure 3 As shown.

[0026] The oil inlet seat 4 has an oil inlet hole 41 on its horizontal side, and the first horizontal through hole 12 is connected to the oil inlet hole 41; the oil inlet seat 4 has a receiving cavity in its vertical direction for fitting with the valve body 1.

[0027] The slide valve 2 also includes a head 21, an oil seal 22, a throttling orifice 23, and an oil outlet 24 disposed within the slide valve 2; the slide valve 2 also has a second vertical cavity and a second horizontal through hole that are perpendicular to each other, the oil seal 22 is disposed within the second vertical cavity, and the second horizontal through hole communicates with the first horizontal through hole 12 in the valve body 1; the outlet end of the second vertical cavity communicates with the throttling orifice 23, and the throttling orifice 23 communicates with the oil outlet 24.

[0028] The oil chamber control block 7 is a shallow oil chamber control block, which is connected to the tail end of the valve body 2 and communicates with the oil outlet 24.

[0029] The piezoelectric ceramic 3 is equipped with a power line, which is connected to the control device in the adjustable oil chamber device 100. The control device can adjust the extension and retraction of the piezoelectric ceramic 3 according to the operating status of the spindle.

[0030] During operation, the piezoelectric ceramic 3's deformation is controlled by the input voltage. The piezoelectric ceramic 3 exhibits inverse piezoelectricity; when an external electric field is applied to it, the positive and negative charge centers within the ceramic 3 undergo relative displacement and become polarized. This displacement causes deformation, with the deformation ΔL = f(U), where U is the voltage supplied to the piezoelectric ceramic 3 by the controller. By controlling the voltage output, the controller can control the minute deformation of the piezoelectric ceramic 3, allowing it to elongate or shorten slightly.

[0031] When the piezoelectric ceramic 3 elongates, the slide valve 2, along with the oil chamber control block 7, moves downward, reducing the oil chamber depth h and increasing the oil film force. When the piezoelectric ceramic 3 shortens, the slide valve 2, along with the shallow oil chamber control block 7, moves upward, increasing the oil chamber depth h and decreasing the oil film force.

[0032] When the control device detects a rotational error when the spindle rotates, it issues a command to control the extension and retraction of the four piezoelectric ceramics 3 on the bearing body 300 to adjust the oil film force, thereby gradually reducing the rotational error when the spindle rotates.

[0033] Specifically, the oil film force mentioned in this application refers to the load-bearing capacity W of the oil film.

[0034]

[0035] in, For oil inlet pressure, For effective bearing area, To design the liquid resistance ratio, For oil film thickness, To design the oil film thickness, the change in the oil cavity depth h directly affects the oil film thickness. As the depth h of the oil cavity increases, the oil film thickness... An increase in the oil cavity depth (h) leads to a decrease in the oil film's load-bearing capacity (W); when the oil cavity depth (h) decreases, the oil film thickness... The decrease in depth results in an increase in the load-bearing capacity W of the oil film. Therefore, the magnitude of the oil film force can be controlled by adjusting the oil cavity depth h.

[0036] It is evident that the greatest advantage of this invention lies in the fact that the piezoelectric ceramic directly participates in the control of the shallow oil cavity depth. When the hydrostatic bearing assembly supports the rotation of the spindle, if a rotational error is detected in the spindle, the rotational error can be compensated by adjusting the depth of the four shallow oil cavities in a coordinated manner, thereby adjusting the magnitude of the oil film force, improving the spindle rotation accuracy, and enabling the spindle to obtain the best support performance.

[0037] Example 2

[0038] like Figure 2 As shown, the difference between this embodiment and Embodiment 1 is that the upper cover plate assembly 5 includes a wire hole 53, a fixing seat 54, and an upper cover plate 55, wherein the wire hole 53 is located at one end of the upper cover plate 55; the piezoelectric ceramic 3 is fixedly connected to the fixing seat 54, and the power line of the piezoelectric ceramic 3 is led out through the wire hole 53 and connected to the control device; the upper cover plate assembly 5 also includes a first fastening mechanism and a second fastening mechanism. In this embodiment, the first fastening mechanism is a clamping screw 51 and a screw through hole located in the center of the upper cover plate 55, which fixes the upper cover plate to the fixing seat; in addition, the second fastening mechanism includes threaded holes 11 located at both horizontal ends of the valve body 1 and countersunk holes 52 located at corresponding positions on the upper cover plate 55 and screws, which fix the upper cover plate assembly 5 to the valve body 1.

[0039] The fixed connection can be selected from various methods as needed, such as welding, threaded connection, pin connection, key connection, interference fit, etc. In this embodiment, a threaded connection is selected for easy disassembly and reduced processing costs. For example, the adjustable oil chamber device 100 is installed on the oil inlet seat 200 by a threaded connection, the valve body 1 is connected to the oil inlet seat 4 by a thread, and the slide valve 2 is connected to the oil chamber control block 7 by a thread; in addition, the oil seat 200 is installed on the bearing body 300 by screws.

[0040] In this embodiment, oil grooves are provided at the contact points of each component to install sealing rings 62 and prevent pressure oil leakage.

[0041] Example 3

[0042] The difference between this implementation and Embodiment 1 or 2 is that the adjustable oil chamber device 100 is further provided with a spring 61, which contacts the lower end face of the head 21 in the slide valve 2. The function of the spring 61 is to precisely control the depth of the oil chamber. The spring 61 can be a disc spring, a leaf spring, a plate spring, etc. In this specific embodiment, a disc spring is selected.

[0043] During operation, when the piezoelectric ceramic 3 extends, the slide valve 2, along with the shallow oil chamber control block 7, moves downward and compresses the disc spring 61, reducing the oil chamber depth h and increasing the oil film force. When the piezoelectric ceramic 3 shortens, the rebound force of the disc spring 61 allows the slide valve 2 and the shallow oil chamber control block 7 to react more promptly, increasing the oil chamber depth h and decreasing the oil film force. When a rotational error is detected during spindle rotation, the oil film force is adjusted by controlling the four piezoelectric ceramics 3 on the bearing body 300, causing the rotational error during spindle rotation to gradually decrease.

[0044] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydrodynamic / hydrostatic bearing assembly, characterized by, The adjustable oil cavity device, the oil inlet seat and the bearing body, the oil inlet seat is installed on the outer surface of the bearing body, and the adjustable oil cavity device is connected with the oil inlet seat; The adjustable oil cavity device comprises a valve body, a spool, a piezoelectric ceramic, an upper cover plate assembly and an oil cavity control block; the valve body has a first vertical cavity therein, the spool and the piezoelectric ceramic are both installed in the first vertical cavity, one end of the piezoelectric ceramic is connected with the upper cover plate assembly, the other end of the piezoelectric ceramic is connected with the upper end of the spool, and the lower end of the spool is connected with the oil cavity control block; the oil cavity control block is a shallow oil cavity control block; When it is detected that the main shaft rotation has a rotation error, the piezoelectric ceramic on the bearing body is controlled to stretch and contract by the control device, so as to adjust the depth of the oil cavity and the oil film force; The valve body further has a first horizontal through hole perpendicular to the first vertical cavity, and the oil inlet seat is provided with an oil inlet hole, and the first horizontal through hole is in communication with the oil inlet hole; The spool comprises a head, an oil seal, a throttle hole and an oil outlet hole, the oil seal, the throttle hole and the oil outlet hole are all arranged in the spool, the spool further has a second vertical cavity, the oil seal is arranged in the second vertical cavity, the oil outlet end of the second vertical cavity is in communication with the throttle hole, the throttle hole is in communication with the oil outlet hole, and the oil outlet hole is in communication with the oil cavity control block; The adjustable oil cavity device further comprises a spring, and the spring is fixedly connected with the lower end surface of the head.

2. The bearing assembly of claim 1, wherein, The spool further has a second horizontal through hole perpendicular to the second vertical cavity, and the second horizontal through hole is in communication with the first horizontal through hole.

3. Bearing assembly according to any of claims 1-2, characterized in that The upper cover plate assembly comprises a fixing seat and an upper cover plate, the piezoelectric ceramic is connected with the fixing seat, and the upper cover plate is connected with the fixing seat.

4. The bearing assembly of claim 3, wherein, The bearing assembly further comprises a control device, the piezoelectric ceramic is provided with a power line, the upper cover plate is provided with a threading hole, and the power line is connected with the power line through the threading hole.

5. The bearing assembly of claim 3, wherein, The upper cover plate assembly further comprises a first fastening mechanism and a second fastening mechanism, the upper cover plate and the fixing seat are fixed by the first fastening mechanism, and the valve body and the upper cover plate are fixed by the second fastening mechanism.

6. The bearing assembly of claim 1, wherein, The spring is a disc spring.

7. The bearing assembly of claim 1, wherein, The adjustable oil cavity device and the oil inlet seat are multiple and are uniformly arranged on the outer surface of the bearing body.

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