Method for controlling unbalance loading of hydrostatic pressure rotary table based on double-sided film throttler

Abstract

The invention discloses a method for controlling unbalance loading of a hydrostatic pressure rotary table based on a double-sided film throttler, and relates to the field of hydrostatic pressure in precision machinery. According to the method, the double-sided film throttler is used as a pressure compensation assembly, the pressure of each opposed oil cavity is automatically adjusted to adapt to the change of an external load, and the double-sided film throttler achieves throttling through a throttling gap between an annular area formed by a specific circular truncated cone and an elastic film piece. The device has the characteristics that through the precise throttling effect of the double-sided film throttler, the unbalance loading floating amount of the hydrostatic pressure rotary table is effectively controlled, and the rotation precision of the rotary table and the surface quality of a machined workpiece are improved. Meanwhile, according to the method, the structure of the static pressure rotary table is simplified, the span of an internal oil way of the static pressure rotary table is reduced, an external oil way does not need to be added, the feedback and response speed is higher, the method is suitable for the working condition of bearing a large load, the rigidity of the hydrostatic pressure rotary table is greatly improved, and the non-uniformity of the unbalance loading floating amount is reduced.

Description

Technical Field

[0001] The invention belongs to the field of liquid static pressure in precision machinery, and in particular relates to a method for controlling the eccentric load of a liquid static pressure turntable based on a double-sided film throttle. Background Art

[0002] The hydrostatic turntable is a precision device that uses hydrostatic support. It has the advantages of large load-bearing capacity and high motion accuracy. Its working principle is to adjust the liquid pressure in the turntable oil chamber through a throttle to form an oil film pressure that balances the external load. It is widely used in ultra-precision machining machine tools. However, in actual applications, when the hydrostatic turntable is subjected to an eccentric load, the floatation of the turntable will often be uneven. In particular, when it is subjected to an eccentric load, the floatation of the turntable will be uneven. This unevenness may affect the rotation accuracy and rigidity of the turntable, and thus seriously affect the stability of the turntable processing and the surface quality and accuracy of the processed workpiece. Therefore, it is particularly important to solve the eccentric load problem of the hydrostatic turntable, improve the processing accuracy and optimize the equipment performance.

[0003] The current types of throttles include: capillary throttles, small hole throttles, and slide valve feedback throttles, but they have great limitations in practical applications. Capillary throttles and small hole throttles are fixed throttles, which allow oil to pass through slender or tiny gap oil channels, and the friction resistance generated is used as the oil channel pressure, but their flow channels are narrow and easy to clog, and they have no self-regulation ability; slide valve feedback throttles rely on the movement of the slide valve to play a feedback role, but the slide valve has a large inertia and is prone to overshoot during the adjustment process. In addition, the structural design of some throttles is too complicated, which makes it difficult to manufacture and adjust. When subjected to a large eccentric load, the throttle may fail to respond in time, which may aggravate the problem of uneven turntable floating.

[0004] To this end, we provide a method for controlling the eccentric load of a liquid hydrostatic turntable based on a double-sided film throttle to solve the above-mentioned problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to design a method for controlling the liquid static pressure turntable based on a double-sided film throttle to prevent uneven floating of the worktable caused by eccentric loading.

[0006] To solve the above technical problems, the present invention is implemented through the following technical solutions.

[0007] The present invention discloses a method for controlling the eccentric load of a liquid hydrostatic turntable based on a double-sided film throttle, comprising a turntable base, a double-sided film throttle, a hydrostatic worktable, a main shaft, a hydrostatic oil chamber, a driving motor, a driving worm, an anti-backlash worm, a worm gear pressure cover, a worm gear support, a coupling, and a reducer; the structure of the double-sided film throttle comprises: a main body, a throttle port, a throttle boss, an upper adjustment oil chamber, an elastic film, and upper and lower adjustment oil chambers; the hydrostatic worktable is installed at the center of the turntable base, and the hydrostatic oil chamber is controlled by the worm gear pressure cover at the bottom of the turntable base and the turntable base. The turret base is provided with six circumferentially evenly distributed static pressure oil chambers, and the six static pressure oil chambers support the static pressure workbench by throttling oil supply through the double-sided film throttle; the oil pump in the oil tank is controlled by a servo motor to extract the hydraulic oil through the oil filter to reach the oil inlet of the double-sided film throttle; it is divided into six paths through the oil distribution port, and enters the upper adjusting oil chamber and the lower adjusting oil chamber of the double-sided film throttle in pairs respectively, and then squeezed out from the throttling port by the throttling boss and the elastic film in the upper adjusting oil chamber and the lower adjusting oil chamber to reach the six static pressure oil chambers of the turret base.

[0008] The present invention is further configured such that the throttling liquid resistance effect is realized by the throttling gap formed between the throttling boss and the elastic film. When the pressure oil flows into the double-sided film throttle from the hydraulic station and is squeezed out by the throttling bosses and the center hole on both sides of the elastic film, a pressure drop is generated and flows into the respective working oil chambers. The two hydraulic oils flowing into the double-sided film throttle enter the upper and lower adjusting chambers and are separated by the elastic film in the middle. When the workpieces on the static pressure workbench are evenly placed without unbalanced load, the elastic film in the throttle is in a straight state, the throttling gaps on both sides are equal, the pressures in the upper and lower adjusting oil chambers are the same, the flow rate flowing out of the turntable base is the same, and the circumferential floating amount of the turntable is the same.

[0009] The present invention is further configured so that when an off-center load phenomenon occurs on the workpiece on the hydrostatic workbench, the forces on the circumferential sides of the hydrostatic workbench are different, and the hydrostatic workbench produces a small displacement in the direction of the off-center load force. The gap between the hydrostatic oil chamber where the bottom surface of the hydrostatic workbench at the off-center load position contacts the turntable base is reduced, that is, the liquid resistance becomes larger, and the pressure in the lower regulating oil chamber of the double-sided film throttle connected to the oil chamber increases. At the off-center load position of the hydrostatic workbench, that is, the gap between the hydrostatic oil chamber at the circumferential direction of °, that is, the opposite position, increases, that is, the liquid resistance decreases, and the pressure in the upper regulating oil chamber of the double-sided film throttle connected to the opposite oil chamber decreases. A pressure difference is generated in the regulating oil chambers on both sides of the elastic film in the flow device. The pressure difference forces the elastic film to bulge upward, which reduces the throttling gap of the upper regulating oil chamber, that is, the throttling fluid resistance of the upper regulating oil chamber becomes larger, causing the pressure of the upper regulating oil chamber to be further reduced, and the throttling gap of the lower regulating oil chamber to be increased, that is, the throttling fluid resistance of the lower regulating oil chamber becomes smaller, causing the pressure of the lower regulating oil chamber to be further increased; in this way, the pressure difference against the external load is further increased, thereby reducing the displacement of the static pressure worktable under the action of the offset load, and causing the surface of the static pressure worktable on the side subjected to the offset load to float upward until it reaches a balanced position.

[0010] The present invention is further configured as follows: three pairs of double-sided film throttles, after the hydrostatic oil chamber is filled with hydraulic oil, when there is sufficient liquid pressure on the working oil chamber to balance the weight of the external load, the hydrostatic workbench surface is floated, and the hydraulic oil in the hydrostatic oil chambers on the six bases at this time flows through the oil sealing edge, and then flows out of the oil chamber, and the pressure outside the chamber is zero. When the floating amount is greater than the radial surface unevenness of the bottom surface of the hydrostatic workbench, it is pure liquid friction.

[0011] The present invention is further configured so that when one side of the hydrostatic workbench surface is subjected to an off-center load, a change in the throttling gap will occur. On the one hand, due to the smaller gap of the hydrostatic oil chamber subjected to the off-center load, the liquid resistance of the oil sealing edge becomes larger, and the oil chamber pressure increases. At the same time, due to the larger gap of the hydrostatic oil chamber at the position opposite to the off-center oil chamber, the liquid resistance of the oil sealing edge becomes smaller, and the oil chamber pressure decreases. The pressure lost due to the liquid resistance in the throttling will become smaller, so that the pressure of the hydraulic oil entering the oil chamber becomes larger, thereby playing a role in controlling the off-center load.

[0012] The present invention has the following beneficial effects.

[0013] 1. The present invention utilizes a double-sided film throttle to control the uneven floating amount of the liquid hydrostatic turntable. When the hydrostatic turntable is overloaded, the oil chamber pressure is automatically adjusted to always keep the table surface level.

[0014] 2. Due to the joint adjustment feedback of the two opposing oil chambers in the turntable base and the double-sided film throttle, the double-sided film liquid hydrostatic turntable has higher oil film stiffness and stability than the traditional fixed throttle and constant flow hydrostatic support; the oil film thickness and pressure will produce smaller changes with different loads and eccentric loads, and the accuracy is higher.

[0015] 3. The double-sided diaphragm throttle is an adjustable pressure compensation component that can automatically adjust the pressure of each oil chamber to adapt to changes in external load. Its throttling effect can control the deformation of the diaphragm and the throttling gap stably, reliably and more accurately, and can reduce vibration and noise caused by pressure fluctuations.

[0016] 4. The double-sided film throttle can adjust the flow rate according to the pressure change needs, and can ensure the lubrication effect between the static pressure turntable and the base. By optimizing the flow control, it can not only improve the operating efficiency of the turntable and reduce energy consumption, but also the good lubrication effect can reduce friction and wear and extend the service life of the turntable.

[0017] 5. The structure of the hydrostatic turntable is simplified, the span of the internal oil circuit of the hydrostatic turntable is reduced, and there is no need to add external oil circuits. The feedback and response speed are faster, which is suitable for working conditions with large loads. The rigidity of the hydrostatic turntable is greatly improved, and the unevenness of the eccentric load floating amount is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for describing the embodiment are briefly introduced below.

[0019] Figure 1 It is a stereoscopic diagram of the overall structure of the present invention.

[0020] Figure 2 It is a bottom view of the overall structure of the present invention.

[0021] Figure 3 It is the principle diagram of the static pressure oil circuit of the present invention.

[0022] Figure 4 It is a cross-sectional view of the present invention.

[0023] Figure 5 It is an exploded view of the local structure of the present invention.

[0024] Figure 6 It is a local structural stereogram of the present invention.

[0025] Figure 7 It is an exploded view of the local structure of the present invention.

[0026] In the attached drawings: 1. first oil chamber; 2. second oil chamber; 3. turntable base; 4. double-sided film throttle; 5 and 12, throttling boss; 6. upper adjustment oil chamber; 7 and 10, throttle oil inlet; 8, throttling gap; 9. elastic film; 11. lower adjustment oil chamber; 13. eccentric load; 14. hydrostatic workbench; 15. main shaft; 16. hydrostatic oil chamber; 17. anti-backlash worm; 18. driving worm; 19, oil outlet; 20. worm cage; 21. reducer; 22. driving motor; 23. anti-backlash worm wheel; 24. driving worm wheel. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] A method for controlling the eccentric load of a hydrostatic turntable based on a double-sided diaphragm throttle: Figure 1-7 As shown: it includes a first oil chamber 1, a second oil chamber 2, a turntable base 3, a double-sided film throttle 4, throttling bosses 5 and 12, an upper adjustment oil chamber 6, throttle oil inlets 7 and 10, a throttling gap 8, an elastic film 9, a lower adjustment oil chamber 11, an eccentric load 13, a static pressure workbench 14, a main shaft 15, a static pressure oil chamber 16 of the turntable base 3, an anti-backlash worm 17, a driving worm 18, an oil outlet 19 of the turntable base 3, a worm retainer 20, a reducer 21, a driving motor 22, an anti-backlash worm wheel 23, and a driving worm wheel 24.

[0029] The hydrostatic workbench 14 is installed at the center position of the turntable base 3. The turntable base 3 has six hydrostatic oil chambers 16 evenly distributed circumferentially. The bottom of the hydrostatic workbench 14 is in contact with the six hydrostatic oil chambers 16 of the turntable base 3. It is installed on the main shaft 15 at the center position of the base. The double-sided film throttle 4 is fixedly installed on the outer surface of the turntable base 3.

[0030] The hydraulic oil in the oil tank reaches three pairs of double-sided film throttles 4, and is divided into six paths through the oil distribution port. From the oil inlet and the throttling gap 8, the hydraulic oil enters the upper adjusting oil chamber 6 and the lower adjusting oil chamber 11 of the double-sided film throttle 4 in pairs, respectively. Then, the hydraulic oil is squeezed out from the throttling port by the throttling bosses 5 and 12 and the elastic film 9 in the upper adjusting oil chamber 6 and the lower adjusting oil chamber 11, and reaches the six static pressure oil chambers 16 of the turntable base 3.

[0031] The hydraulic oil squeezed out from the upper adjusting oil chamber 6 and the lower adjusting oil chamber 11 of the double-sided film throttle 4 reaches the static pressure oil chamber 16 of the turntable base 3. When the static pressure worktable 14 is unbalanced, the oil chamber pressure increases, and the elastic film 9 in the double-sided film throttle 4 bends and deforms, so that the throttling gap 8 between the elastic film 9 and the throttling bosses 5 and 12 or the upper adjusting oil chamber 6 increases, the oil outlet resistance decreases, and the flow rate entering the static pressure oil chamber 16 through the throttling gap 8 increases, so that the thickness of the oil film supporting the liquid static pressure worktable 14 changes very little.

[0032] When the six-way hydrostatic oil chamber 16 is filled with hydraulic oil, the oil pressure is sufficient to support the hydrostatic worktable 14 to float. At this time, the hydraulic oil flows in through the six hydrostatic oil chambers 16 of the turntable base 3, and then flows out to the oil outlet 19 through the sealing edge of the hydrostatic oil chamber 16. The pressure outside the chamber is close to zero. When the floating amount is greater than the surface unevenness of the radial plane of the turntable base 3, pure liquid friction is formed.

[0033] The pairs of static pressure oil chambers 16 are dynamically adjusted by the upper adjusting oil chamber 6 and the lower adjusting oil chamber 11 of the double-sided film throttle 4 respectively. The hydraulic oil in the upper adjusting oil chamber 6 flows out through the throttling gap 8 to a static pressure oil chamber 16 opposite to the turntable base 3, and the hydraulic oil in the lower adjusting oil chamber 11 flows out through the throttling gap 8 to a static pressure oil chamber 16 opposite to the turntable base 3.

[0034] When the workpiece on the hydrostatic workbench 14 is biasedly loaded with a heavy object 13, one side is biased downward. At this time, the forces on each side of the hydrostatic workbench 14 are uneven, and the hydrostatic workbench 14 is biased toward the oil chamber, which reduces the oil chamber gap of the oil chamber, that is, the liquid resistance increases, and the pressure in the lower regulating oil chamber 11 of the double-sided film throttle 4 connected to the oil chamber increases. At this time, the gap between the opposite oil chamber of the oil chamber, that is, the hydrostatic oil chamber 16 of the oil chamber, increases, that is, the liquid resistance decreases, and the pressure in the upper regulating oil chamber 6 of the double-sided film throttle 4 connected to the oil chamber decreases. At this time, a pressure difference is generated between the upper regulating oil chamber 6 and the lower regulating oil chamber 11 on both sides of the elastic film 9 in the double-sided film throttle 4. The pressure difference forces the elastic film 9 to protrude upward, so that the throttling gap 8 of the upper regulating oil chamber 6 is reduced, that is, the throttling liquid resistance of the upper oil chamber is increased, which causes the pressure in the upper regulating oil chamber 6 to be further reduced.

[0035] The throttling gap 8 of the lower adjusting oil chamber 11 is increased, that is, the throttling fluid resistance of the lower adjusting oil chamber is reduced, so that the pressure of the lower adjusting oil chamber 11 is further increased; thus, the pressure difference resisting the external load is further increased, so that the initial displacement of the static pressure worktable 14 under the action of the eccentric load 13 is reduced, so that the static pressure worktable 14 on the side of the eccentric load 13 floats upward until it reaches a balanced position.

[0036] The oil pressure of the static pressure oil chamber 16 of the turntable base 3 is controlled by the upper regulating oil chamber 6 and the lower regulating oil chamber 11 of the double-sided film throttle 4 to control the unbalanced load phenomenon during operation, achieve dynamic balance and realize precise control.

[0037] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that technicians in the relevant technical field can better understand and utilize the present invention.

Claims

1. A method for controlling the eccentric load of a hydrostatic turntable based on a double-sided film throttle, characterized in that: It comprises a turntable base (3), a double-sided film throttle (4), a static pressure worktable (14), a main shaft (15), a static pressure oil chamber (16), a driving motor (22), a driving worm (18), an anti-backlash worm (17), a worm gear cover, a worm gear bracket, a coupling, and a reducer (21); The structure of the double-sided film throttle (4) comprises: a body, a throttle port, throttle bosses (5) and (12), an upper regulating oil chamber (6), an elastic film (9), and upper and lower regulating oil chambers (11); The static pressure workbench (14) is installed at the center of the turntable base (3), and floats by contacting the worm gear pressure cover at the bottom of the turntable base (3) with the static pressure oil chamber (16) of the turntable base (3). The turntable base (3) has six static pressure oil chambers (16) evenly distributed in the circumferential direction. The six static pressure oil chambers (16) support the static pressure workbench (14) by throttling oil supply through the double-sided film throttle (4). The servo motor controls the oil pump in the oil tank to extract the hydraulic oil through the oil filter to reach the oil inlet of the double-sided film throttle (4); the oil is divided into six paths through the oil distribution port, and enters the upper regulating oil chamber (6) and the lower regulating oil chamber (11) of the double-sided film throttle (4) in pairs, respectively, and then is squeezed out from the throttle port by the throttling bosses (5) and (12) and the elastic film (9) in the upper regulating oil chamber (6) and the lower regulating oil chamber (11), and reaches the six static pressure oil chambers (16) of the turntable base (3).

2. A method for controlling the load eccentricity of a hydrostatic turntable based on a double-sided film throttle according to claim 1, characterized in that: The throttling fluid resistance effect is realized by the throttling gap (8) formed between the throttling bosses (5) and (12) and the elastic film (9). When the pressure oil flows from the hydraulic station into the double-sided film throttle (4), and then squeezed out from the center holes of the throttling bosses (5) and (12) on both sides of the elastic film (9), a pressure drop is generated and flows into the respective working oil chambers. The two hydraulic oils flowing into the double-sided film throttle enter the upper and lower adjustment chambers and are separated by the elastic film (9) in the middle. When the workpieces on the static pressure workbench (14) are evenly placed without unbalanced load, the elastic film (9) in the throttle is in a straight state, the throttling gaps (8) on both sides are equal, the pressures of the upper and lower adjustment oil chambers (11) are the same, the flow rate flowing out of the turntable base (3) is the same, and the circumferential floating amount of the turntable is the same.

3. The method for controlling the load imbalance of a hydrostatic turntable based on a double-sided film throttle according to claim 1, characterized in that: When the workpiece on the hydrostatic workbench (14) is overloaded, the circumferential sides of the hydrostatic workbench (14) are subjected to different forces, and the hydrostatic workbench (14) produces a small displacement in the direction of the overload force. The gap between the hydrostatic oil chamber (16) where the bottom surface of the hydrostatic workbench (14) at the overload position contacts the turntable base (3) is reduced, i.e., the fluid resistance increases. The pressure in the lower regulating oil chamber (11) of the double-sided film throttle (4) connected to the oil chamber increases. At the overload position of the hydrostatic workbench (14), the gap between the hydrostatic oil chamber (16) at the opposite position, i.e., 180° around the circumference, increases, i.e., the fluid resistance decreases. The pressure in the upper regulating oil chamber (6) of the double-sided film throttle (4) connected to the opposite oil chamber decreases. At this time, a pressure difference is generated in the regulating oil chambers on both sides of the elastic film (9) in the throttle. The pressure difference forces the elastic film (9) to bulge upward, thereby reducing the throttling gap (8) of the upper regulating oil chamber (6), that is, the throttling fluid resistance of the upper regulating oil chamber becomes larger, causing the pressure of the upper regulating oil chamber (6) to be further reduced, and the throttling gap (8) of the lower regulating oil chamber (11) to be increased, that is, the throttling fluid resistance of the lower regulating oil chamber becomes smaller, causing the pressure of the lower regulating oil chamber (11) to be further increased; thus, the pressure difference resisting the external load is further increased, thereby reducing the displacement of the static pressure workbench (14) under the action of the offset load, causing the surface of the static pressure workbench (14) on the side subjected to the offset load to float upward until reaching a balanced position.

4. The method for controlling the load imbalance of a hydrostatic turntable based on a double-sided film throttle according to claim 1, characterized in that: Three pairs of double-sided film throttles (4) are provided. After the hydrostatic oil chamber (16) is filled with hydraulic oil, when there is enough liquid pressure on the working oil chamber to balance the weight of the external load, the hydrostatic workbench (14) is floated. At this time, the hydraulic oil in the hydrostatic oil chamber (16) on the six bases flows through the oil sealing edge and then flows out of the oil chamber. The pressure outside the chamber is zero. When the floating amount is greater than the radial surface unevenness of the bottom surface of the hydrostatic workbench (14), it is pure liquid friction.

5. The method for controlling the load imbalance of a hydrostatic turntable based on a double-sided film throttle according to claim 1, characterized in that: When one side of the hydrostatic workbench (14) is subjected to an offset load, the throttling gap (8) will change. On the one hand, the hydrostatic oil chamber (16) subjected to the offset load has a smaller gap, and the liquid resistance of the oil sealing side becomes larger, so the oil chamber pressure increases. At the same time, the hydrostatic oil chamber (16) at the opposite position of the offset oil chamber has a larger gap, and the liquid resistance of the oil sealing side becomes smaller, so the oil chamber pressure decreases. The pressure loss due to the liquid resistance in the throttling will decrease, so that the pressure of the hydraulic oil entering the oil chamber becomes larger, which plays a role in controlling the offset load.

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