CN108194453A - A kind of hydrostatic support sealing fluid cylinder pressure of anti-bias load - Google Patents

Abstract

The present invention is a kind of anti-eccentric load static pressure support sealing hydraulic cylinder, which includes static pressure piston, static pressure guide sleeve, static pressure connecting body, piston rod, upper and lower cylinder body, upper and lower cylinder cover, sealing ring; The piston and the inner wall of the hydraulic cylinder, the piston rod and the guide sleeve are based on the principle of hydrostatic support sealing, and the gap between the piston and the inner wall of the hydraulic cylinder, the piston rod and the guide sleeve is used to generate a hydrostatic support oil film, so that the piston or piston rod ""suspended" in the hydraulic oil; a reasonable gap can effectively prevent the leakage of the hydraulic oil. The invention greatly reduces the friction force generated by the seal ring of the traditional hydraulic cylinder, which is beneficial for the hydraulic cylinder to resist the lateral load and has It is beneficial to the correction of the piston, which can improve the vibration frequency and positioning accuracy of the hydraulic cylinder, and improve the motion stability and dynamic response of the moving parts.

Description

A Static Pressure Bearing Sealed Hydraulic Cylinder Anti-eccentric Load

technical field

The invention belongs to the professional field of hydraulic transmission. By optimizing the structure of the hydraulic cylinder piston and guide sleeve, and using the principle of static pressure support sealing, the friction force generated by the sealing ring of the hydraulic cylinder is greatly reduced, which is beneficial for the hydraulic cylinder to resist side loads and can improve the hydraulic cylinder. Excellent vibration frequency and positioning accuracy prolong the working life of the hydraulic cylinder and are suitable for the technical field of hydraulic cylinders.

Background technique

As the actuator and power element of the hydraulic system, the performance of the hydraulic cylinder directly affects the control accuracy and response speed of the system. Compared with ordinary hydraulic cylinders, hydraulic cylinders require less friction and excellent lateral load resistance to meet the requirements of heavy loads and eccentric loads at high frequencies. Usually, the piston rod and the piston of the hydraulic cylinder are often sealed with a seal. This sealing structure increases the frictional resistance when the piston moves, resulting in a decrease in the dynamic performance of the hydraulic cylinder and even greatly shortening the working life of the hydraulic cylinder. At the same time, when the hydraulic cylinder is designed, it is usually only considered to bear the axial force, and the radial force is balanced by hinged at both ends. However, in actual working conditions, the hydraulic cylinder will bear a certain lateral load. Lateral eccentric load will increase the friction force at the seal of the hydraulic cylinder, affect the response speed and control accuracy, and cause problems such as low-speed crawling, leakage and even seal failure.

Under this background, referring to the principle of hydrostatic bearing and gap sealing principle, the hydraulic cylinder using the principle of hydrostatic bearing and sealing can well fulfill the above sealing requirements, making it an important research direction of modern hydraulic transmission. Aiming at the deficiencies of the existing hydraulic cylinder technology, the problems of high friction, short working life, low dynamic performance and working stability. Starting from the design and structure optimization of the piston and guide sleeve, the piston and guide sleeve used in the hydraulic cylinder are studied systematically and deeply.

Contents of the invention

The purpose of the present invention is to overcome the disadvantages of the above-mentioned existing hydraulic cylinder technology, and to design a static pressure bearing seal hydraulic cylinder with anti-eccentric load, which greatly reduces the traditional hydraulic cylinder sealing ring seal. The generated friction force is beneficial for the hydraulic cylinder to resist the lateral load and the deviation correction of the piston, which can improve the vibration frequency and positioning accuracy of the hydraulic cylinder, and improve the motion stability and dynamic responsiveness of the moving parts.

The present invention is an anti-eccentric load static pressure bearing sealed hydraulic cylinder, which is characterized in that it comprises a static pressure piston (5), a static pressure guide sleeve (10), a static pressure connecting body (3), a piston rod (7), an upper and lower Cylinder body, upper and lower cylinder heads, sealing ring (11); the static pressure piston (5) and the piston rod (7) are connected by threads, and the upper and lower cylinder bodies are threaded or welded through the static pressure connecting body (3) The upper and lower cylinder heads and the cylinder body of the hydraulic cylinder are sealed by sealing rings (11) and connected by bolts; the hydrostatic piston (5) is characterized in that four The rectangular oil chamber (17) has an oil inlet hole in the middle of each rectangular oil chamber, and two annular oil unloading grooves (16) are opened at both ends of the rectangular oil chamber, and each annular oil unloading groove is provided with a Oil discharge hole (18); the piston rod (7) is characterized in that the piston rod adopts a stepped shaft structure, and an oil inlet hole (24) is opened at the center of the small diameter shaft end, and an oil outlet hole is opened below the oil inlet hole (23), and ensure that the central angle of the oil inlet hole and the oil outlet hole is 45°; four evenly distributed through holes are opened at the positions corresponding to the rectangular oil chamber of the hydrostatic piston (5) to communicate with the oil inlet hole on the piston rod ;A through hole is set at the position opposite to the static pressure piston annular oil discharge groove to communicate with the oil outlet hole on the piston rod (23), and the through holes are connected; the static pressure guide sleeve (10) is characterized in that the static pressure guide sleeve (10) is static Four I-shaped oil chambers (13) are evenly opened on the inner wall of the pressure guide sleeve (10), and an oil inlet hole (8) is opened in the middle of each I-shaped oil chamber. Annular oil unloading grooves (14), oil unloading holes (12) are opened at the bottom of each annular oil unloading groove; the static pressure connecting body (3) is characterized in that the static pressure connecting body is used to connect the upper and lower cylinders, and at the same time The piston rod (7) acts as a guide. In order to avoid leakage, four rectangular oil chambers (20) are evenly opened on the inner wall of the connector, and an oil inlet hole (4) is opened in the middle of each rectangular oil chamber. And two annular oil unloading grooves (22) are opened at the two ends of the rectangular oil chamber, and an oil unloading hole (21) is opened at the bottom of each annular oil unloading groove.

The gap between the piston and the inner wall of the cylinder, the piston rod and the guide sleeve is 15-30 μm.

Beneficial effects: the present invention greatly reduces the frictional force generated by sealing the traditional hydraulic cylinder with a sealing ring, which is beneficial for the hydraulic cylinder to resist lateral loads, is conducive to the correction of the piston, and can improve the vibration frequency and positioning accuracy of the hydraulic cylinder. Improve the motion stability and dynamic response of moving parts.

Description of drawings

For ease of illustration, the present invention is described in detail by the following specific implementations and accompanying drawings.

Figure 1 is a schematic diagram of the structure of the hydraulic cylinder. In the figure: 1 lower cylinder head, 2 lower cylinder body, 3 static pressure connection body, 4 connection body oil inlet hole, 5 static pressure piston, 6 upper cylinder body, 7 piston rod, 8 guide sleeve oil inlet hole, 9 upper cylinder Cover, 10 static pressure guide sleeve, 11 seal ring, 12 guide sleeve oil discharge hole, 13 guide sleeve oil chamber, 14 guide sleeve oil discharge groove, 15 hydraulic cylinder oil inlet hole, 16 piston oil discharge groove, 17 piston oil chamber, 18 piston Drain hole, 19 hydraulic cylinder oil outlets, 20 connecting body oil chambers, 21 connecting body oil outlets, 22 connecting body oil unloading grooves, 23 piston rod oil outlets, 24 piston rod oil inlets.

Fig. 2 is a schematic diagram of the structure of the hydrostatic piston.

Fig. 3 is a structural schematic diagram of a hydrostatic guide sleeve.

Fig. 4 is a schematic diagram showing the inner wall of the guide sleeve unfolded. In the figure: 1. Circumferential oil seal, 2. Static pressure bearing oil chamber, 3. Oil inlet, 4. Oil discharge groove, 5. Oil discharge hole.

Fig. 5 is a partial sectional view of the piston rod.

Fig. 6 is a schematic diagram of the structure of the hydrostatic connector.

Fig. 7 is a schematic diagram of the working principle of the hydrostatic bearing oil supply system. In the figure: 1 oil tank, 2 electric motor, 3 hydraulic pump, 4 overflow valve, 5 one-way valve, 6 oil filter, 7 fine oil filter, 8 accumulator, 9 variable throttle valve, 10 pressure gauge, 11 Solenoid valve, 12 throttle valves, 13 static pressure support structures.

Fig. 8 is a schematic diagram of the principle of static pressure support.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention is described below through specific embodiments shown in the accompanying drawings. It should be understood, however, that these descriptions are exemplary only and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

Structural composition of the present invention is shown in Figure 1, Figure 2, Figure 3, Figure 4. The present invention is an anti-eccentric load static pressure bearing sealed hydraulic cylinder, which is characterized in that it comprises a static pressure piston (5), a static pressure guide sleeve (10), a static pressure connecting body (3), a piston rod (7), an upper and lower Cylinder body, upper and lower cylinder heads, sealing ring (11); the static pressure piston (5) and the piston rod (7) are connected by threads, and the upper and lower cylinder bodies are threaded or welded through the static pressure connecting body (3) The upper and lower cylinder heads and the cylinder body of the hydraulic cylinder are sealed by sealing rings (11) and connected by bolts; the hydrostatic piston (5) is characterized in that four The rectangular oil chamber (17) has an oil inlet hole in the middle of each rectangular oil chamber, and two annular oil unloading grooves (16) are opened at both ends of the rectangular oil chamber, and each annular oil unloading groove is provided with a Oil discharge hole (18); the piston rod (7) is characterized in that the piston rod adopts a stepped shaft structure, and an oil inlet hole (24) is opened at the center of the small diameter shaft end, and an oil outlet hole is opened below the oil inlet hole (23), and ensure that the central angle of the oil inlet hole and the oil outlet hole is 45°; four evenly distributed through holes are opened at the positions corresponding to the rectangular oil chamber of the hydrostatic piston (5) to communicate with the oil inlet hole on the piston rod ;A through hole is set at the position opposite to the static pressure piston annular oil discharge groove to communicate with the oil outlet hole on the piston rod (23), and the through holes are connected; the static pressure guide sleeve (10) is characterized in that the static pressure guide sleeve (10) is static Four I-shaped oil chambers (13) are evenly opened on the inner wall of the pressure guide sleeve (10), and an oil inlet hole (8) is opened in the middle of each I-shaped oil chamber. Annular oil unloading grooves (14), oil unloading holes (12) are opened at the bottom of each annular oil unloading groove; the static pressure connecting body (3) is characterized in that the static pressure connecting body is used to connect the upper and lower cylinders, and at the same time The piston rod (7) acts as a guide. In order to avoid leakage, four rectangular oil chambers (20) are evenly opened on the inner wall of the connector, and an oil inlet hole (4) is opened in the middle of each rectangular oil chamber. And two annular oil unloading grooves (22) are opened at the two ends of the rectangular oil chamber, and an oil unloading hole (21) is opened at the bottom of each annular oil unloading groove.

The working principle of the present invention is shown in Figure 5. Before the system works, the overflow valve (4) is in an unloaded state. After the motor (2) starts, the hydraulic pump (3) starts to supply oil. When the oil supply pressure of the hydraulic pump After stabilization, the pressure of the relief valve is set slightly higher than the working pressure, and the hydraulic oil passes through the check valve (5), oil filter (6), fine oil filter (7), variable throttle valve (9), throttling Throttle valve (12) begins to supply oil to the hydraulic cylinder. The hydraulic oil flows in from the oil inlet hole of the piston rod and flows out from the static pressure groove of the piston. When a certain pressure is reached, a static pressure support groove is formed to float the piston, and the hydraulic oil flows into the hydraulic cylinder and returns through the oil outlet of the hydraulic cylinder. to the oil tank (1) to complete the working cycle; the pressure oil flowing into the static pressure support guide sleeve will float the piston rod when the static pressure chamber reaches a certain pressure, and the hydraulic oil will flow back to the oil tank through the oil discharge hole on the side of the guide sleeve (1 ) to complete the duty cycle.

After the pressure oil flows into the piston support groove or the static pressure oil chamber of the guide sleeve, a static pressure support oil film with a certain pressure is formed, and the pressure difference between the static pressure oil grooves (oil chambers) is used to form a certain bearing capacity, and the piston (piston rod) ) float and bear a certain side load, realize the sealing and guiding of the piston (piston rod), prevent the dry friction state between the piston and the inner wall of the hydraulic cylinder (piston rod and the inner wall of the support sleeve) in direct contact, and avoid making the piston and the hydraulic cylinder The inner wall (piston rod and inner wall of the support sleeve) wears and leaks. Since the hydraulic oil film is filled between the piston and the inner wall of the hydraulic cylinder (piston rod and guide sleeve), the piston and the inner wall of the hydraulic cylinder (piston rod and guide sleeve) are separated from each other without direct contact, and the friction force is only the liquid viscous force. It greatly reduces the friction generated by traditional hydraulic cylinders sealed with sealing rings, and can improve the vibration frequency and positioning accuracy of hydraulic cylinders.

When the piston rod is subjected to a radial load F , the gap between the oil chamber and the piston rod changes. Since the inlet flow of hydraulic oil in each oil chamber is constant, that is, Q is a constant value, when the gap changes, the pressure in the oil chamber also changes. Will change accordingly. For example, when the piston rod is subjected to the radial load F shown in Figure 6, the clearance of the oil chamber 2 becomes smaller, and the pressure of the oil chamber becomes larger; on the contrary, because the clearance of the oil chamber 1 becomes larger, the pressure of the oil chamber becomes smaller , which produces a pressure difference, and then produces a radial force opposite to F to balance the piston rod at a certain position.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the above description. What is described in the above description is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention also has various changes and modifications. Improvements, these changes and improvements are within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. A static pressure bearing sealed hydraulic cylinder with anti-eccentric load, characterized in that it includes a static pressure piston (5), a static pressure guide sleeve (10), a static pressure connecting body (3), a piston rod (7), an upper and lower cylinder Body, upper and lower cylinder heads, sealing ring (11); the static pressure piston (5) and the piston rod (7) are connected by threads, and the upper and lower cylinder bodies are threaded or welded through the static pressure connecting body (3). The upper and lower cylinder heads and the cylinder body of the hydraulic cylinder are sealed by sealing rings (11) and connected by bolts. 2. The static pressure piston (5) according to claim 1 is characterized in that four rectangular oil cavities (17) are evenly opened on the outer surface of the piston, and an oil inlet is opened in the middle of each rectangular oil cavity There are two annular oil unloading grooves (16) at both ends of the rectangular oil chamber, and oil unloading holes (18) are provided at the bottom of each annular oil unloading groove. 3. The piston rod (7) according to claim 1 is characterized in that the piston rod adopts a stepped shaft structure, an oil inlet hole (24) is opened at the center of the small diameter shaft end, and an outlet hole is opened below the oil inlet hole. oil hole (23), and ensure that the central angle of the oil inlet hole and the oil outlet hole is 45°; four evenly distributed through holes are opened at the position corresponding to the rectangular oil chamber of the hydrostatic piston (5) and the oil inlet on the piston rod The holes communicate with each other; a through hole communicates with the oil outlet hole on the piston rod (23) at a position opposite to the annular oil discharge groove of the static pressure piston, and the through holes communicate with each other. 4. The static pressure guide sleeve (10) according to claim 1 is characterized in that four I-shaped oil chambers (13) are evenly opened on the inner wall of the static pressure guide sleeve (10), and each I-shaped An oil inlet hole (8) is provided in the middle of the oil chamber, an annular oil discharge groove (14) is provided at both ends of the I-shaped oil chamber, and an oil discharge hole (12) is provided at the bottom of each annular oil discharge groove. 5. The static pressure connector (3) according to claim 1 is characterized in that, the static pressure connector is used to connect the upper and lower cylinders, and at the same time guide the piston rod (7), in order to avoid leakage , four rectangular oil chambers (20) are evenly opened on the inner wall of the connecting body, an oil inlet hole (4) is opened in the middle of each rectangular oil chamber, and two ring-shaped unloading holes are opened at both ends of the rectangular oil chamber The oil groove (22) is provided with an oil discharge hole (21) at the bottom of each annular oil discharge groove.