An inner feedback type static pressure rotary table fan-shaped single oil pad experimental device

Abstract

The application discloses an inner feedback type static pressure rotary table fan-shaped single oil pad experimental device, which comprises a static pressure supporting system, and the static pressure supporting system is supplied with oil by an oil supply system. The upper oil pad and the lower oil pad of the static pressure supporting system are fixed on a supporting guide rail by bolts, the supporting guide rail is arranged in a U-shaped supporting plate, the upper oil pad and the lower oil pad respectively face the upper and lower inner walls of the U-shaped supporting plate, and the U-shaped supporting plate and the upper oil pad and the U-shaped supporting plate and the lower oil pad form oil film thicknesses respectively. An inner feedback oil path is hidden in the supporting guide rail through an inner hole. The supporting guide rail is supported and connected by supporting rods, the outside of the U-shaped supporting plate is provided with a magnetic level gauge, the bottom of the U-shaped supporting plate is provided with a pressure sensor, the bottom of the pressure sensor is provided with a vertical mounting screw rod, the height of the U-shaped supporting plate is adjusted by the screw rod, three hand wheels are connected with the screw rod, and the height of the screw rod is adjusted by rotating the hand wheels. The application can detect the load bearing performance of the single oil pad, does not need to build an entire static pressure rotary table, and reduces the cost.

Description

Technical Field

[0001] This invention is an experimental device for an internal feedback hydrostatic sector-shaped single oil pad, belonging to the field of mechanical design and manufacturing. Background Technology

[0002] With the need for national transformation and upgrading, the machine tool industry is gradually moving towards mid-to-high-end products, placing higher demands on the core functional components of machine tools. Among these, the hydrostatic rotary table is a crucial part of various precision and ultra-precision machine tools. Compared to traditional radial and axial bearings, it offers advantages such as high-precision rotation, low friction, and high load-bearing capacity, and is widely used in heavy-duty ultra-precision machinery fields such as aerospace and shipbuilding. The hydrostatic oil pad, which bears the load, is one of the most critical components of the hydrostatic rotary table. Its working principle involves using an oil pump to supply oil and various throttling methods to create a hydrostatic effect in the oil pad, significantly improving the rotary table's performance. Therefore, it is essential to study the various dynamic and static characteristics of the oil pad during operation and to design a test bench. There are many experimental devices for hydrostatic turntables in China. Typical structures of existing hydrostatic turntable experimental devices are described in patents CN102980755A and CN105458744A. While these structures can experimentally study the overall characteristics of the hydrostatic turntable, the compact structure makes overall design and manufacturing difficult and costly. Therefore, from an experimental verification perspective, it is entirely possible to design an experimental device that studies only a single set of oil pads. Existing hydrostatic turntable experimental devices with throttling devices are described in CN105424361B. This device allows for the replacement of different throttling devices, facilitating the study of the impact of different throttling devices on the load-bearing performance of the hydrostatic turntable. Unlike the aforementioned patents, the throttling device of this invention uses a slot throttling method located inside the oil pad and can form an internal feedback oil circuit.

[0003] This invention proposes an internal feedback hydrostatic turntable fan-shaped single oil pad experimental device. The study of only a single oil pad can not only reduce the cost of processing and use, but also provide a basis for the development of high load-bearing and high-precision precision and ultra-precision hydrostatic turntables. In addition, the internal feedback fan-shaped oil pad structure with gap throttling can also greatly improve its load-bearing performance. Summary of the Invention

[0004] This invention mainly designs an experimental device for studying the load-bearing characteristics of a single oil pad on an internal feedback hydrostatic turntable, realizing the study of the influence of different parameters (such as oil film thickness, oil pad parameters, oil supply pressure, etc.) on the load-bearing capacity and load-bearing stiffness of the oil pad.

[0005] The technical problem to be solved by the present invention is achieved by the following technical solution.

[0006] An internal feedback hydrostatic turntable fan-shaped single oil pad experimental device includes a hydrostatic support system, which is supplied with oil by an oil supply system.

[0007] The hydrostatic support system includes a U-shaped support plate 1, an upper oil pad 2, a lower oil pad 3, a support guide rail 4, a magnetic level 5, a support rod 6, a pressure sensor 7, a lead screw 9, a frame 10, a door 11, and a handwheel 12. The upper oil pad 2 and the lower oil pad 3 are fixed to the support guide rail 4 by bolts. The support guide rail 4 is located inside the U-shaped support plate 1. The upper oil pad 2 and the lower oil pad 3 are respectively opposite the upper and lower inner walls of the U-shaped support plate 1. Oil film thicknesses are formed between the U-shaped support plate 1 and the upper oil pad 2, and between the U-shaped support plate 1 and the lower oil pad 3. The internal feedback oil circuit is hidden inside the support guide rail 4 through the inner hole. The support guide rail 4 is supported and connected by the support rod 6. A magnetic level 5 is provided on the outside of the U-shaped support plate 1. A pressure sensor 7 is provided at the bottom of the U-shaped support plate 1. A vertically mounted lead screw 9 is provided at the bottom of the pressure sensor 7. The height of the U-shaped support plate 1 is adjusted by the lead screw 9. Three handwheels 12 are connected to the lead screw 9. The height of the lead screw 9 is adjusted by rotating the handwheels 12.

[0008] Oil enters through the oil inlet on the side of the support rail 4 below the upper oil pad 2 via an oil pipe. After passing through the inner hole, it flows to the oil inlet 25 in the middle of the upper and lower oil pads respectively. The upper and lower oil pads are connected in parallel, and the pressure of the oil flowing into the upper and lower oil pads is the same. After flowing into the oil pads, it returns to the opposite oil pad after throttling, forming a static pressure effect. After the static pressure effect is formed, an oil film is formed, and the oil film generates static pressure to be applied to the U-shaped support plate 1. Since both the upper oil pad 2 and the lower oil pad 3 provide pressure, the pressure difference between the upper and lower oil pads 3 is reflected in the pressure sensor 7. When the oil film thickness of the lower oil pad 3 is less than the oil film thickness of the upper oil pad 2, the pressure of the upper oil pad 2 is less than the pressure of the lower oil pad 3, and the resultant force of the upper oil pad 2 and the lower oil pad 3 on the U-shaped support plate is downward. When the oil film thickness of the upper oil pad 2 is less than the oil film thickness of the lower oil pad 3, the pressure of the lower oil pad 3 is less than the pressure of the upper oil pad 2, and the resultant force of the upper oil pad 2 and the lower oil pad 3 on the U-shaped support plate 1 is upward.

[0009] Furthermore, the oil film thickness is controlled by three handwheels 12 to rotate the lead screw 9. The lead screw 9 adjusts the support and height of the U-shaped support plate 1 to achieve adjustment, converting the rotational motion of the adjustment handwheel 12 into the up-and-down linear motion of the U-shaped support plate 1. A worm gear reducer is selected to perform unidirectional self-locking on the rotation of the adjustment handwheel 12.

[0010] Furthermore, the lead of the lead screw 9 is 2mm.

[0011] Furthermore, in the internal feedback oil circuit, the oil enters the oil inlet chamber 26 from the oil inlet 25 at the center of the lower oil pad 3, is throttled through the gaps 27 on both sides, generates a pressure drop, reaches the oil collection chamber, and then flows into the oil hole in the oil collection chamber. It then flows through the oil passage in the support guide rail 4 and into the upper working oil chamber 29. The oil supplied from the upper oil pad 2 by the oil pump is throttled and flows into the lower working oil chamber. The pressure in the upper working oil chamber 29 is obtained by throttling the oil supplied by the oil pump through the throttle of the lower working oil chamber, and the pressure in the lower working oil chamber is obtained by throttling the oil supplied by the oil pump through the throttle of the upper working oil chamber. When the U-shaped support plate 1 moves downward, the gap between the lower oil pad and the U-shaped support plate 1 increases, the hydraulic resistance decreases, and the flow rate increases; while the gap between the upper oil pad and the support plate decreases, the hydraulic resistance increases, and the flow rate decreases. The pressure in the upper working oil chamber 29 increases due to two factors: firstly, the increased hydraulic resistance of the sealing edge 30 within the oil chamber; and secondly, the decreased hydraulic resistance of the lower throttle 22, which increases the incoming oil pressure (i.e., reduces the pressure drop), resulting in a higher pressure in the upper working oil chamber 29. Conversely, the pressure in the lower working oil chamber decreases. This pressure difference between the upper and lower working oil chambers acts on the effective support area of ​​the oil pad, creating the ability to resist external loads.

[0012] Furthermore, the oil supply system is controlled by a motor 14 to draw oil from the oil tank 13, through a filter 15, an overflow valve 20, a high-pressure ball valve 19, an oil pipe 18, and a series of oil passage blocks 17 into the oil pad. The pressure is reduced by a throttle valve inside the oil pad, achieving a constant pressure effect. The oil then returns to the return oil tank 16 through the sealing edge of the oil pad. The oil supply system is equipped with a cooling device.

[0013] Furthermore, the oil supply system adopts a constant pressure oil supply, and the oil pad has a slit throttling device 22 inside.

[0014] Compared to other hydrostatic turntable experimental setups, the advantages of this invention are:

[0015] 1. This device can test the load-bearing capacity of a single oil pad without the need to build the entire hydrostatic turntable, which greatly reduces costs.

[0016] 2. This device uses an internal feedback oil pad and employs gap throttling, which can provide an effective theoretical basis for the study of turntables with similar structures.

[0017] 3. The oil pad of this device is removable, and the oil film thickness can be actively changed. Compared with a real hydrostatic turntable, this device is more experimental. Generally, a real hydrostatic turntable is a relatively compact structure, and it is difficult to disassemble after it is made. In addition, this device does not need to bear heavy objects, but only needs to be reflected by force sensors, thus reducing the requirements for materials.

[0018] 4. Based on the arrangement of various sensors, this device is capable of real-time acquisition of oil film bearing capacity, oil supply flow rate, oil supply pressure, and oil chamber pressure. Attached Figure Description

[0019] Figure 1 This is a structural diagram of an experimental device for an internal feedback hydrostatic turntable with a sector-shaped single oil pad.

[0020] Figure 2 This is a schematic diagram of the supporting structure;

[0021] Figure 3 This is a diagram of the oil pad structure;

[0022] Figure 4 This is a schematic diagram of the internal feedback principle.

[0023] Figure 5 The diagram shows the internal oil circuit of the bearing. (a) is the overall structure diagram, (b) is the BB cross-sectional view, (c) is the CC cross-sectional view, and (d) is the DD cross-sectional view. Detailed Implementation

[0024] The following is a combination of structural appendix Figure 1 , Figure 2 and working principle Figure 3 , Figure 4 , Figure 5 This device will be described in further detail.

[0025] An internal feedback hydrostatic turntable fan-shaped single oil pad experimental device mainly includes: a support plate 1, an upper oil pad 2, a lower oil pad 3, a support guide rail 4, a magnetic level 5, a support rod 6, a pressure sensor 7, a transparent glass plate 8, a lead screw 9, a frame 10, a door 11, a handwheel 12, an oil tank 13, a motor 14, a filter 15, a return oil tank 16, an oil circuit block 17, an oil pipe 18, a high-pressure ball valve 19, an overflow valve 20, an instrument panel 21, a feedback throttle 22, a spherical hinge 23, a reducer 24, an oil pad inlet 25, an oil inlet chamber 26, a throttling edge 27, an oil collecting chamber 28, a working oil chamber 29, and an oil sealing edge 30.

[0026] Connections between the various parts that make up the device:

[0027] The hydrostatic support system includes a U-shaped support plate 1, an upper oil pad 2, a lower oil pad 3, a support guide rail 4, a magnetic level 5, a support rod 6, a pressure sensor 7, a transparent glass plate 8, a lead screw 9, a frame 10, a door 11, and handwheels 12. An oil film is formed between the U-shaped support plate 1 and the upper and lower oil pads 2 and 3. The upper and lower oil pads 2 and 3 are fixed to the support guide rail 4 with bolts. The internal feedback oil circuit is hidden inside the support guide rail 4 through internal holes. The magnetic level 5 is attached to the surface of the support plate. At least three pressure sensors 7 are placed under the U-shaped support plate 1 to ensure the support plate is level. The lead screw 9 is connected to the pressure sensors to adjust the height of the support plate. The transparent glass plate 8 is mounted on the U-shaped support plate 1 for subsequent installation of displacement sensors to measure displacement. Three handwheels 12 are connected to the lead screw, and the height of the lead screw is adjusted by manually rotating the handwheels.

[0028] The hydrostatic support system operates as follows: oil enters through the oil pipe from the inlet on the right side of the support guide rail 4 below the oil pad 2, and flows through the inner hole to the middle inlet 25 of the upper and lower oil pads respectively. Since the upper and lower oil pads are connected in parallel, the pressure flowing into the upper and lower oil pads is the same. After flowing into the oil pads, it returns to the opposite oil pad after throttling, forming a hydrostatic effect, such as... Figure 5 The arrow in the image points in the direction of the static pressure effect. After the static pressure effect is formed, an oil film of about 20 micrometers will be formed. This oil film will generate a large static pressure applied to the U-shaped support plate. Since both the upper and lower oil pads provide a certain pressure, the pressure difference between the upper and lower oil pads is reflected on the pressure sensor. If the oil film thickness of the lower oil pad is less than that of the upper oil pad, then the pressure of the upper oil pad is less than that of the lower oil pad, and the resultant force of the upper and lower oil pads on the support plate should be downward. Similarly, when the oil film thickness of the upper oil pad is less than that of the lower oil pad, then the pressure of the lower oil pad is less than that of the upper oil pad, and the resultant force of the upper and lower oil pads on the support plate should be upward. The thickness of the oil film can be adjusted manually by adjusting the screw 9 using three handwheels 12. Figure 2 The schematic diagram of the support structure is shown below: The support and height adjustment of the U-shaped support plate require the rotational motion of the adjusting handwheel 12 to be converted into the vertical linear motion of the support plate. At the same time, in order to achieve a certain level of motion accuracy for this structure, the reducer needs to have a certain one-way self-locking function. Based on the above conditions, a worm gear reducer should be selected. The lead of this lead screw is set to 2mm. Since its oil film thickness is on the order of 0.02mm, a smaller lead is selected to meet its motion accuracy. The total reduction ratio may be relatively large, so a two-stage reducer is selected.

[0029] The internal feedback oil circuit works on the principle of reference. Figure 3 , 4The oil enters the oil inlet chamber 26 from the oil inlet 25 in the center of the oil pad. After being throttled by the gaps 27 on both sides, a certain pressure drop is generated, and the oil reaches the oil collection chamber. Then it flows into the oil hole in the oil collection chamber, passes through the oil passage in the guide rail, and flows into the opposite working oil chamber 29. Similarly, the oil pad on the opposite side is throttled after being supplied by the oil pump and flows into this oil chamber. In short, the pressure in the upper working oil chamber is obtained by the oil pump supplying oil through the throttle of the lower oil chamber, and the pressure in the lower working oil chamber is obtained by the oil pump supplying oil through the throttle of the upper oil chamber. When the U-shaped plate moves downward, the gap between the lower oil pad and the plate increases, the hydraulic resistance decreases, and the flow rate increases; while the gap between the upper oil pad and the support plate decreases, the hydraulic resistance increases, and the flow rate decreases. Therefore, the pressure in the upper working oil chamber 29 increases on the one hand due to the increased hydraulic resistance of the sealing edge 30 in the oil chamber, and on the other hand due to the decreased hydraulic resistance of the lower throttle 22, which increases the pressure of the incoming oil (i.e., the pressure drop decreases), making the pressure in the upper oil chamber 29 even higher. The pressure in the lower working oil chamber becomes even lower. The pressure difference between the upper and lower working oil chambers acts on the effective support area of ​​the oil pad, forming the ability to resist external loads.

[0030] The oil supply system, such as Figure 1 As shown, the system includes an oil tank 13, a motor 14, a filter 15, a return oil tank 16, an oil passage block 17, an oil pipe 18, a high-pressure ball valve 19, a relief valve 20, and an instrument panel 21. This oil supply system is controlled by a motor 14 to draw oil from the oil tank 13, through the filter 15, relief valve 20, high-pressure ball valve 19, oil pipe 18, and a series of oil passage blocks 17, into the static pressure oil pads 2 and 3. The pressure is reduced by a throttle valve inside the oil pad, achieving a constant pressure. The oil then returns to the return oil tank 16 through the sealing edge of the oil pad. The oil supply system should have a cooling device to maintain the oil temperature at room temperature, preventing it from becoming too high.

[0031] The oil supply system is divided into quantitative oil supply and constant pressure oil supply. The first type uses a separate oil pump for each oil pad to maintain a quantitative oil supply, or uses a single oil pump but a separate flow control valve for each oil pad to maintain a quantitative oil supply. In this way, each oil pad works independently without affecting the others. The second type, constant pressure oil supply, uses a single oil pump to directly supply oil to multiple oil pads. Once the oil pad with the least load is working, the working pressure of the oil pump will not increase further. To allow the oil pump pressure to continue to rise, a liquid resistor, also called a throttle, is installed in the oil line with the least load. When the oil flows through the liquid resistor, a pressure drop occurs, thus forcing the oil pump's supply pressure to exceed the pressure required by the oil chamber. This device uses a constant pressure oil supply method, and the throttle is located inside the oil pad, employing a slit throttling mechanism 22. This oil supply system is controlled by a motor 14 to draw oil from the oil tank 13, through a series of oil circuit blocks 17 such as filter 15, overflow valve 20, high-pressure ball valve 19, and oil pipe 18, into the static pressure oil pad 2,3. The pressure is reduced by the gap throttle inside the oil pad to form a constant pressure effect; while the oil returns to the return oil tank 16 through the oil sealing edge of the oil pad.

[0032] Compared to other hydrostatic turntable experimental setups, the advantages of this invention are:

[0033] 1. This device can test the load-bearing capacity of a single oil pad without the need to build the entire hydrostatic turntable, which greatly reduces costs.

[0034] 2. This device uses an internal feedback oil pad and employs gap throttling, which can provide an effective theoretical basis for the study of turntables with similar structures.

[0035] 3. The oil pad of this device is removable, and the oil film thickness can be actively changed. Compared with a real hydrostatic turntable, this device is more experimental. Generally, a real hydrostatic turntable is a relatively compact structure, and it is difficult to disassemble after it is made. In addition, this device does not need to bear heavy objects, but only needs to be reflected by force sensors, thus reducing the requirements for materials.

[0036] 4. Based on the arrangement of various sensors, this device is capable of real-time acquisition of oil film bearing capacity, oil supply flow rate, oil supply pressure, and oil chamber pressure.

Claims

1. An internal feedback hydrostatic turntable fan-shaped single oil pad experimental device, characterized in that, This includes a hydrostatic support system, which is supplied with oil by an oil supply system; The hydrostatic support system includes a U-shaped support plate, an upper oil pad, a lower oil pad, a support guide rail, a magnetic level, a support rod, a pressure sensor, a lead screw, a frame, a door, and handwheels. The upper and lower oil pads are fixed to the support guide rail with bolts. The support guide rail is located inside the U-shaped support plate. The upper and lower oil pads are respectively positioned opposite the upper and lower inner walls of the U-shaped support plate. Oil film thicknesses are formed between the U-shaped support plate and the upper oil pad, and between the U-shaped support plate and the lower oil pad, respectively. The internal feedback oil circuit is hidden inside the support guide rail through an inner hole. The support guide rail is supported and connected by a support rod. A magnetic level is provided on the outside of the U-shaped support plate. A pressure sensor is provided at the bottom of the U-shaped support plate. A vertically mounted lead screw is provided at the bottom of the pressure sensor, and the height of the U-shaped support plate is adjusted by the lead screw. Three handwheels are connected to the lead screw, and the height of the lead screw is adjusted by rotating the handwheels. Oil enters through the oil inlet on the side of the support rail below the upper oil pad via an oil pipe. After passing through the inner hole, it flows separately to the oil inlets in the middle of the upper and lower oil pads. The upper and lower oil pads are connected in parallel, and the pressure flowing into them is the same. After flowing into the oil pads, the oil returns to the opposite oil pad after being throttled, forming a static pressure effect. After the static pressure effect is formed, an oil film is formed, which generates static pressure applied to the U-shaped support plate. Since both the upper and lower oil pads provide pressure, the pressure difference between the upper and lower oil pads is reflected on the pressure sensor. When the oil film thickness of the lower oil pad is less than that of the upper oil pad, the pressure of the upper oil pad is less than that of the lower oil pad, and the resultant force of the upper and lower oil pads on the U-shaped support plate is downward. When the oil film thickness of the upper oil pad is less than that of the lower oil pad, the pressure of the lower oil pad is less than that of the upper oil pad, and the resultant force of the upper and lower oil pads on the U-shaped support plate is upward.

2. The internal feedback hydrostatic turntable sector-shaped single oil pad experimental device according to claim 1, characterized in that, The oil film thickness is controlled by three handwheels to rotate the lead screw. The lead screw adjusts the support and height of the U-shaped support plate, thus converting the rotational motion of the adjustment handwheel into the vertical linear motion of the U-shaped support plate. A worm gear reducer is used to perform unidirectional self-locking of the rotation of the adjustment handwheel.

3. The internal feedback hydrostatic turntable sector-shaped single oil pad experimental device according to claim 1, characterized in that, The lead of the lead screw is 2mm.

4. The internal feedback hydrostatic turntable sector-shaped single oil pad experimental device according to claim 1, characterized in that, In the internal feedback oil circuit, the oil enters the oil inlet chamber from the oil inlet at the center of the lower oil pad, is throttled through the gaps on both sides, generating a pressure drop and reaching the oil collecting chamber, then flows into the oil hole in the oil collecting chamber, through the oil circuit in the support guide rail, and into the upper working oil chamber; the oil from the upper oil pad is throttled after being supplied by the oil pump, and flows into the lower working oil chamber; the pressure in the upper working oil chamber is obtained by throttling the oil supplied by the oil pump through the throttle of the lower working oil chamber, and the pressure in the lower working oil chamber is obtained by throttling the oil supplied by the oil pump through the throttle of the upper working oil chamber; when the U-shaped support plate When the displacement is downward, the gap between the lower oil pad and the U-shaped support plate increases, the hydraulic resistance decreases and the flow rate increases; while the gap between the upper oil pad and the support plate decreases, the hydraulic resistance increases and the flow rate decreases; the pressure in the upper working oil chamber increases on the one hand due to the increased hydraulic resistance of the sealing edge in the oil chamber, and on the other hand due to the decreased hydraulic resistance of the lower throttle, which increases the pressure of the incoming oil, i.e., the pressure drop decreases, making the pressure in the upper working oil chamber even higher; the pressure in the lower working oil chamber becomes lower; the pressure difference between the upper and lower working oil chambers acts on the effective support area of ​​the oil pad, forming the ability to resist external loads.

5. The internal feedback hydrostatic turntable sector-shaped single oil pad experimental device according to claim 1, characterized in that, The oil supply system is controlled by a motor to draw oil from the oil tank, through a filter, overflow valve, high-pressure ball valve, and a series of oil passage blocks, into the oil pad. The pressure is reduced by a throttle valve inside the oil pad to achieve a constant pressure. The oil then returns to the oil tank through the sealing edge of the oil pad. The oil supply system is equipped with a cooling device.

6. The internal feedback hydrostatic turntable sector-shaped single oil pad experimental device according to claim 1, characterized in that, The oil supply system adopts constant pressure oil supply, and the oil pad has a gap for throttling inside.

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