Swing type hydraulic actuator

Abstract

The invention provides a swing type hydraulic actuator, relates to the field of swing hydraulic cylinders, and aims to solve the problem that a sealing structure of an existing swing hydraulic cylinder is poor in sealing performance and durability. Wedge-shaped surfaces of the end face sealing ring and the axial combined sealing ring are used for performing preliminary pre-tightening on the two kinds of sealing; meanwhile, the annular tensioning oil cavity is formed in the end cover, the pressure of the annular tensioning oil cavity is adjusted according to the working environment requirement, the end cover deforms to act on the end face sealing ring and the axial combined sealing ring, secondary pre-tensioning is provided for the end face sealing ring and the axial combined sealing ring, and the environmental adaptability of the blade type swing oil cylinder is improved.

Description

Technical Field

[0001] The invention relates to the field of swing hydraulic cylinders, and in particular to a swing type hydraulic actuator. Background Art

[0002] The hydraulic swing cylinder can achieve a wide range of motion and angle adjustment by outputting hydraulic pressure. It can withstand large loads and provide stable motion control. It is widely used in aerospace, robotics and automation systems, and engineering machinery. Currently, common hydraulic swing cylinders include gear rack swing cylinders, spiral swing cylinders, and vane swing cylinders. Compared with the other two types of hydraulic cylinders, the vane swing cylinder has a small moment of inertia, sensitive movement, uniform rotation, small pulsation, simple manufacturing, and low cost. However, it is difficult to seal the cylinder internally, the seal life is short, it is prone to leakage, and the volumetric efficiency is low, which limits the application of the vane swing cylinder in high-pressure environments.

[0003] During the operation of the vane swing cylinder, there are mainly radial seals between the stator and rotor blades and end face rotary seals between the blades and the rotating shaft. The end face rotary seal needs to prevent circumferential oil leakage between the blades and leakage from the sealing cavity to the external environment, which requires high precision in the processing and assembly of the sealing contact surface. The sealing gap cannot be adjusted during the system pressure change, resulting in over-preload or seal failure, making the vane swing cylinder poorly adaptable to the working environment. Summary of the invention

[0004] The purpose of the present invention is to provide a swing type hydraulic actuator in view of the defects of the prior art, in which a cavity is formed by a cylinder body and a rotating shaft to accommodate stator blades and rotor blades, and the wedge-shaped surfaces of the end face sealing ring and the axial combined sealing ring are used to perform preliminary pre-tightening on the two seals; at the same time, an annular tightening oil chamber is arranged on the end cover, and the pressure of the annular tightening oil chamber is adjusted according to the working environment requirements, so that the deformation of the end cover acts on the end face sealing ring and the axial combined sealing ring, providing a second pre-tightening for the end face sealing ring and the axial combined sealing ring, thereby improving the environmental adaptability of the blade-type swing cylinder.

[0005] In order to solve the above problems, the following solutions are adopted:

[0006] A swing type hydraulic actuator comprises a cylinder body and a rotating shaft, wherein a cavity is formed inside the cylinder body, end covers of the cylinder body are arranged at both ends of the cavity, rotor blades are arranged on the rotating shaft, stator blades are arranged in the cavity, the rotating shaft and the cylinder body are rotatably matched, and the rotor blades and the inner wall of the cavity form a sliding seal;

[0007] In the axial direction of the rotating shaft, the rotating shaft is sequentially sleeved with end face sealing rings and axial combined sealing rings on the outside of the two ends of the rotor blades. The end face sealing rings and the ends of the rotor blades are squeezed and fitted. An annular tensioning oil chamber is provided in the end cover. The annular tensioning oil chamber can act on the axial combined sealing ring and exert radial centripetal and axial extrusion force toward the rotor blades, so that a rotating seal is formed between the end cover and the rotating shaft.

[0008] Furthermore, the axial combined sealing ring includes an annular seal, a wedge ring, and a drum spring which are sequentially sleeved along the radial centrifugal direction. The fitting position of the annular seal and the wedge ring is a conical surface. In the radial direction of the rotating shaft, the drum spring and the annular tensioning oil chamber are arranged opposite to each other and receive the radial action of the annular tensioning oil chamber.

[0009] Furthermore, a compression ring is sleeved outside the annular seal, and the compression ring abuts against the end of the end face sealing ring away from the rotor blades with a conical surface. The compression ring receives the radial centripetal and axial squeezing force of the annular tightening oil chamber toward the rotor blades to squeeze the annular seal and the end face sealing ring.

[0010] Furthermore, one end of the end face sealing ring abuts against the first sealing shoulder of the rotating shaft, the cross-section of the end face sealing ring is an arched structure, and an annular compression spring is embedded inside. The axial combined sealing ring abuts against the second sealing shoulder of the rotating shaft through a spacer ring, and the rotating shaft is connected to the end cover through a bearing, and the bearing abuts against the bearing positioning shoulder of the rotating shaft.

[0011] Furthermore, the axial combined sealing ring also includes an O-ring, which is located at one end of the axial combined sealing ring away from the end face sealing ring and abuts against the end cover.

[0012] Furthermore, after the rotating shaft is installed on the cylinder body, the cavity is annular, the stator blades divide the annular cavity, and oil ports communicating with the outside are respectively provided on both sides of the stator blades.

[0013] Furthermore, the stator blades and rotor blades are respectively provided with sealing grooves opened along the axial direction, and blade sealing gaskets are interference fit in the sealing grooves. The blade sealing gaskets on the stator blades slide in contact with the outer circumferential surface of the rotating shaft, and the blade sealing gaskets on the rotor blades slide in contact with the inner circumferential surface and end surface of the inner wall of the cavity.

[0014] Furthermore, the ends of the rotor blades at the connection positions with the rotating shaft are respectively provided with arc-shaped notches, and one end of the end face sealing ring is filled in the arc-shaped notch to form a seal.

[0015] Furthermore, the annular tensioning oil chambers are spaced apart upwardly from the end cover ring, and adjacent annular tensioning oil chambers are connected via damping oil chambers. The cross-sectional area of ​​the damping oil chamber is smaller than that of the annular tensioning oil chamber to reserve deformation space.

[0016] Furthermore, the annular tensioning oil chamber is connected to the regulating hole through the oil channel, and the regulating hole is equipped with a pressure regulating screw plug, which can change the relative position with the regulating hole to change the pressure in the oil channel and the annular tensioning oil chamber.

[0017] Compared with the prior art, the present invention has the following advantages and positive effects:

[0018] (1) In order to solve the problem of poor sealing and durability of the sealing structure of the current swing hydraulic cylinder, a cavity is formed by the cylinder body and the rotating shaft to accommodate the stator blades and the rotor blades, and the wedge-shaped surfaces of the end face sealing ring and the axial combined sealing ring are used to preliminarily pre-tighten the two seals; at the same time, an annular tensioning oil chamber is set on the end cover, and the pressure of the annular tensioning oil chamber is adjusted according to the working environment requirements, so that the deformation of the end cover acts on the end face sealing ring and the axial combined sealing ring, providing a second pre-tightening for the end face sealing ring and the axial combined sealing ring, thereby improving the environmental adaptability of the blade-type swing hydraulic cylinder.

[0019] (2) The cross section of the end face seal ring is an arched structure with an annular compression spring embedded inside. The axial combined seal is provided with a drum spring to jointly compensate for the sealing gap after the seal wears out, thereby increasing the service life of the end face rotary seal. The structure of the end face seal ring and the axial combined seal ring can better ensure that the swing cylinder maintains its sealing ability during the rotary reciprocating motion, and has the characteristics of low friction, small structural space and good sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 It is an exploded view of the swing type hydraulic actuator in Example 1 of the present invention.

[0022] Figure 2 It is a cross-sectional schematic diagram of the swing type hydraulic actuator in Example 1 of the present invention.

[0023] Figure 3 It is a cross-sectional schematic diagram of the swing type hydraulic actuator in Example 1 of the present invention.

[0024] Figure 4 Schematic diagram of the end face sealing ring in Example 1 of the present invention.

[0025] Figure 5 This is a schematic diagram of the axial combined sealing ring in Example 1 of the present invention.

[0026] Figure 6 Schematic diagram of the end cover and the internal damping oil chamber in Example 1 of the present invention.

[0027] Figure 7This is a schematic diagram of the axial combined sealing ring and the hollow rotating shaft in Example 1 of the present invention.

[0028] In the figure, 1, pressure regulating screw plug; 2, deep groove ball bearing; 3, plug; 4, pressure ring; 5, blade seal; 6, second bolt; 7, pressure cover; 8, first bolt; 9, end cover; 10, axial combined seal ring; 11, spacer ring; 12, end face seal ring; 13, hollow shaft; 14, first O-ring; 15, cylinder wall; 101, third O-ring; 102, screw plug rod; 103, pressure regulating head; 201, A cavity; 202, B cavity; 203, A oil port; 204, B Oil port; 205, stator blade; 206, rotor blade; 207, sealing groove; 901, annular tensioning oil chamber; 902, damping oil chamber; 903, adjusting hole; 904, oil channel; 1001, annular seal; 1002, wedge ring; 1003, drum spring; 1004, second O-ring; 1201, annular compression spring; 1202, end face sealing ring body; 1301, first sealing shoulder; 1302, second sealing shoulder; 1303, bearing locating shoulder. DETAILED DESCRIPTION

[0029] Example 1

[0030] In a typical embodiment of the present invention, Figure 1-Figure 7 As shown, a swing type hydraulic actuator is provided.

[0031] During operation, the blade-type swing cylinder mainly has radial seals between the stator blades 205 and the rotor blades 206, and end face rotary seals between the blades and the rotating shaft. The end face rotary seals need to prevent circumferential oil leakage between the blades and prevent the sealing cavity from leaking to the external environment, which requires high precision in the processing and assembly of the sealing contact surfaces. The sealing gap cannot be adjusted during the system pressure change, resulting in over-preload or sealing failure, making the blade-type swing cylinder poorly adaptable to the working environment; based on this, the present embodiment provides a swing-type hydraulic actuator, which forms a closed chamber through the end cover 9, the cylinder wall 15 and the hollow shaft 13, and the stator blades 205 and the rotor blades 206 divide the closed chamber into high-pressure and low-pressure chambers; in the process of bolting the end cover 9 and the cylinder wall 15, the wedge-shaped surfaces of the end face sealing ring 12 and the axial combined sealing ring 10 are used to preliminarily preload the two seals; at the same time, an annular tightening oil chamber 901 is set on the end cover 9, and the oil chamber pressure is changed by adjusting the depth of the pressure regulating screw plug 1 according to the working environment requirements, so that the inner wall surface of the end cover 9 is deformed inward, providing a second preload for the end face sealing ring 12 and the axial combined sealing ring 10, thereby improving the environmental adaptability of the blade-type swing cylinder; at the same time, the spring set on the end face sealing ring 12 and the drum spring 1003 set on the axial combined seal compensate for the sealing gap after the seal wears, thereby improving the service life of the end face rotating seal.

[0032] like Figure 1 , Figure 2 and Figure 3 As shown, this example provides a single-blade swing oil cylinder with an adaptive end face rotary seal, including a cylinder body and a rotating shaft. A cavity is formed inside the cylinder body, and end covers 9 of the cylinder body are provided at both ends of the cavity. The main body is the cylinder body, and the cylinder body includes a cylinder wall 15 and cylinder covers at both ends. The rotating shaft and the cylinder body rotate in cooperation, and the cylinder body and the rotating shaft form a sealed cavity. The rotating shaft adopts a hollow rotating shaft 13, and the hollow rotating shaft can be arbitrarily installed on the output shaft or the output shaft end through the key groove, without position restrictions, and various installation methods can adapt to different working environments.

[0033] In the axial direction of the shaft, the shaft is sequentially sleeved with end face sealing rings 12 and axial combined sealing rings 10 on the outside of the two ends of the rotor blades 206. The end face sealing rings 12 and the ends of the rotor blades 206 are squeezed and fitted together. An annular tensioning oil chamber 901 is provided in the end cover 9. The annular tensioning oil chamber 901 can act on the axial combined sealing ring 10 and exert radial centripetal and axial squeezing forces toward the rotor blades 206, so that a rotating seal is formed between the end cover 9 and the shaft.

[0034] like Figure 3 As shown, rotor blades 206 are arranged on the outside of the hollow shaft 13, and stator blades 205 are arranged on the inside of the cylinder wall 15. After the shaft is installed on the cylinder body, the cavity is annular. The stator blades 205 separate the sealed cavity in the shape of the ring 11, and oil ports connected to the outside are arranged on both sides of the stator blades 205. The blades divide the sealed cavity into A cavity 201 and B cavity 202. A oil port 203 and B oil port 204 are arranged on both sides of the stator blades 205. The oil ports are opened from the side of the stator blades 205 to provide more direct hydraulic force. During the operation of the swing hydraulic actuator, according to the different directions of hydraulic oil introduction, the A cavity 201 and the B cavity 202 will be periodically converted into a high-pressure cavity and a low-pressure cavity. The oil in the high-pressure cavity drives the hollow shaft 13 to rotate in the direction of the low-pressure cavity by pushing the rotor blades 206. A keyway is arranged in the hollow part of the hollow shaft 13, and torque can be output at any axial position.

[0035] like Figure 3 As shown, the stator blades 205 and the rotor blades 206 are respectively provided with sealing grooves 207 opened along the axial direction, and the blade sealing gaskets 5 are interference fit in the sealing grooves 207. The blade sealing gaskets 5 on the stator blades 205 are slidably fitted with the outer circumferential surface of the rotating shaft, and the blade sealing gaskets 5 on the rotor blades 206 are slidably fitted with the inner circumferential surface and the end surface of the inner wall of the cavity.

[0036] In this embodiment, a sealing groove 207 is provided between the stator blade 205 and the rotor blade 206, and the blade sealing gasket 5 is installed in the sealing groove 207. The thickness, height and radial width of the blade sealing gasket 5 are all greater than the width, height and radial width of the sealing groove 207. Two arc-shaped notches are provided on the side of the blade sealing gasket 5 close to the hollow shaft 13 to cooperate with the end face sealing ring 12 to prevent the hydraulic oil from leaking from the shoulder of the hollow shaft 13. At the same time, through the extrusion cooperation during the assembly process of the hollow shaft 13, the cylinder wall 15 and the end covers 9 on both sides, internal leakage between the A cavity 201 and the B cavity 202 can be prevented. Sealing grooves are provided on the end faces on both sides of the cylinder wall 15, and a first O-ring 14 is provided inside and pressed by the end cover 9. At the same time, the first bolt 8 is used to tighten the end covers 9 and the cylinder wall 15 on both sides in series to prevent external leakage.

[0037] like Figure 1 and Figure 4 As shown, the first sealing shoulder 1301, the second sealing shoulder 1302 and the bearing positioning shoulder 1303 are sequentially arranged on the far axis side of the hollow shaft 13. One end of the end face sealing ring 12 abuts against the first sealing shoulder 1301 of the shaft. The cross section of the end face sealing ring 12 is an arched structure, and an annular compression spring 1201 is embedded inside. Figure 4 As shown, the axial combined sealing ring 10 abuts against the second sealing shoulder 1302 of the rotating shaft through the spacer ring 11, the rotating shaft is connected to the end cover 9 through the bearing, and the bearing abuts against the bearing positioning shoulder 1303 of the rotating shaft.

[0038] The axial combined sealing ring 10 includes an annular seal 1001, a wedge ring 1002, and a drum spring 1003 which are sequentially sleeved along the radial centrifugal direction. The fitting position of the annular seal 1001 and the wedge ring 1002 is a conical surface. In the radial direction of the rotating shaft, the drum spring 1003 is arranged opposite to the annular tensioning oil chamber 901, and receives the radial action of the annular tensioning oil chamber 901; a pressure ring 4 is also sleeved on the outside of the annular seal 1001, and the pressure ring 4 abuts against the end of the end face sealing ring 12 away from the rotor blades 206 with a conical surface. The pressure ring 4 receives the extrusion force of the annular tensioning oil chamber 901 radially toward the centripetal and axially toward the rotor blades 206 to squeeze the annular seal 4 and the end face sealing ring 12.

[0039] Specifically, in the present embodiment, arc-shaped notches are respectively provided at the ends of the rotor blades 206 at the connection positions with the rotating shaft, and one end of the end face sealing ring 12 is filled in the arc-shaped notch to form a seal. The end face sealing ring 12 is mounted on the first sealing shaft shoulder 1301, and the end face sealing ring 12 and the hollow rotating shaft 13 are interference fits. The rotation of the hollow rotating shaft 13 drives the end face sealing ring 12 to rotate at the same time, and the sealing surface where the end face sealing ring 12 contacts the blade is set as an arc surface, and the radius is larger than the arc-shaped notch set on the blade sealing pad 5, so as to ensure that the end face sealing ring 12 and the blade sealing pad 5 always maintain close contact during the output rotation of the swing hydraulic actuator, thereby preventing internal leakage of oil in a high-pressure environment.

[0040] The pressure ring 4 and the end face seal are in close contact, and the sealing contact surface is conical, ensuring that the axial compression force of the pressure ring 4 makes the end face seal ring 12 clamp to the axis and the first sealing shoulder 1301. An annular compression spring 1201 is arranged inside the end face seal ring 12 to provide an initial clamping force, so that the inner ring of the end face seal ring body 1202 can be close to the outer wall of the hollow shaft 13, reducing the axial leakage trend, and at the same time, when the outer ring of the end face seal ring body 1202 is worn after long-term work, it can provide a certain compensation effect on the wear gap.

[0041] like Figure 2 and Figure 5 As shown, an axial combined sealing ring 10 is installed on the second sealing shoulder 1302, and the upper end face of the axial combined sealing ring 10 is pressed by the end cover 9. Since the axial combined seal is a static seal and the end face sealing ring 12 is a dynamic seal, a spacer ring 11 is arranged between the two to prevent relative friction between the two groups of seals. The lower end face of the axial combined seal presses the spacer ring 11, and the spacer ring 11 presses the second sealing shoulder 1302. Multiple axial limiters can prevent the axial combined sealing ring 10 from failing in sealing due to movement.

[0042] like Figure 7 As shown, the axial combined sealing ring 10 is provided with an annular seal 1001 , a wedge ring 1002 , a drum spring 1003 , and a second O-ring 1004 . A plurality of wear-reducing grooves are arranged on the contact surface between the annular seal 1001 and the hollow rotating shaft 13 to reduce the friction area during the rotation process and form a plurality of sealing belts to prevent external leakage of the hydraulic oil; the inner cone surface of the wedge ring 1002 presses the outer cone surface of the annular seal 1001, and when the end cover 9 is connected to the cylinder wall 15 through the first bolt 8, the end cover 9 generates a downward pressing force to ensure that the annular seal 1001 is subjected to a clamping force toward the axis and a clamping force toward the second sealing shoulder 1302; a sealing groove 207 is arranged on the upper end surface of the wedge ring 1002, and a second O-ring 1004 is arranged inside to prevent external leakage of the hydraulic oil; an annular groove is arranged on the outer ring of the wedge ring 1002, and a drum spring 1003 is arranged inside. During the downward extrusion of the wedge ring 1002, the drum-shaped protrusion on the surface of the spring is compressed to generate strain energy, which strengthens the axial clamping force during the axial combined seal rotation friction process, and at the same time, when the inner ring of the annular seal 1001 is worn after long-term work, it can provide a certain compensation effect on the wear gap.

[0043] like Figure 1As shown, the bearing adopts a deep groove ball bearing 2, the inner ring of the deep groove ball bearing 2 and the hollow shaft 13 are clearance fit, the end face of the inner ring of the deep groove ball bearing 2 contacts the bearing positioning shoulder 1303 of the hollow shaft 13, the outer ring of the deep groove ball bearing 2 and the bearing seat hole set on the end cover 9 form an interference fit, the end face of the outer ring of the deep groove ball bearing 2 is matched with the lower end face of the pressure cover 7, the pressure cover 7 and the end cover 9 are connected by the second bolt 6, the deep groove ball bearing 2 is pressed to support the free rotation of the hollow shaft 13.

[0044] like Figure 1 and Figure 6 As shown, the annular tensioning oil chambers 901 are distributed in an upward direction around the end cover 9 at intervals, and adjacent annular tensioning oil chambers 901 are connected through damping oil chambers 902. The cross-sectional area of ​​the damping oil chamber 902 is smaller than that of the annular tensioning oil chamber 901 to reserve deformation space.

[0045] Specifically, Figure 6 As shown, an annular tensioning oil chamber 901 and a damping oil chamber 902 are provided on the inner side surface of the end cover 9 near the two groups of seals. The annular tensioning oil chamber 901 is obtuse-angled along the inner cross section of the end cover 9, and the damping oil chamber 902 has a smaller cross-sectional area to ensure that the annular tensioning oil chamber 901 is connected. The two oil chambers are arranged at intervals and evenly distributed circumferentially, and the oil chambers are filled with pressure medium.

[0046] The annular tensioning oil chamber 901 is connected to the regulating hole 903 through the oil passage 904. The regulating hole 903 is equipped with a pressure regulating screw plug 1. The pressure regulating screw plug 1 can change the relative position with the regulating hole 903 to change the pressure in the oil passage 904 and the annular tensioning oil chamber 901. The annular tensioning oil chamber 901 produces a corresponding deformation amount according to the pressure of the internal medium. The damping oil chamber 902 prevents the inner side of the end cover 9 from deforming unevenly and controls the pressure change inside the oil chamber more accurately.

[0047] The end cover 9 is provided with an oil passage 904 on the outer side surface connected with the annular tensioning oil chamber 901 for initial injection and guidance of the pressure medium. The end of the oil passage 904 is blocked by a plug 3 to prevent external leakage of the pressure medium.

[0048] An adjustment hole 903 is provided on the outer end surface of the end cover 9. The adjustment hole 903 can be divided into a threaded hole and a pressure regulating hole. The adjustment hole 903 is connected to the oil passage 904, the annular tensioning oil chamber 901 and the damping oil chamber 902, and the inside is filled with pressure medium. A pressure regulating screw plug 1 is arranged inside the adjustment hole 903. The pressure regulating screw plug 1 is composed of a screw plug rod 102 and a pressure regulating head 103. The threads on the screw plug rod 102 cooperate with the threaded hole. The pressure regulating head 103 cooperates with the pressure regulating hole. The pressure regulating head 103 is provided with two sealing grooves 207. The third O-ring 101 is sleeved in the sealing groove 207. The outer diameter of the third O-ring 101 is larger than the pressure regulating hole to prevent the pressure medium in the oil passage 904 from leaking from the adjustment hole 903.

[0049] Specifically, when the pressure regulating screw plug 1 is screwed into the hole, the pressure regulating head 103 will compress the pressure medium, so that the pressure in the annular tensioning oil chamber 901 increases, the inner side of the end cover 9 is deformed, and the compression ring 4 is compressed perpendicular to the cone surface, and is transmitted to the end face sealing ring 12 through the compression ring 4. At the same time, an inward compression force is generated on the axial combined seal, increasing the contact pressure between the two sets of seals and the hollow shaft 13, performing secondary pretightening, and improving the sealing performance. When the pressure regulating screw plug 1 is screwed out of the hole, the oil pressure can be released, reducing the contact pressure between the seal and the hollow shaft 13. The screw-in depth of the pressure regulating screw plug 1 can be adaptively adjusted according to the degree of working pressure to prevent over-pretightening or the occurrence of sealing gaps.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A swing type hydraulic actuator, characterized in that: It includes a cylinder body and a rotating shaft, a cavity is formed inside the cylinder body, end covers of the cylinder body are arranged at both ends of the cavity, rotor blades are arranged on the rotating shaft, stator blades are arranged in the cavity, the rotating shaft and the cylinder body are rotatably matched, and the rotor blades and the inner wall of the cavity form a sliding seal; In the axial direction of the rotating shaft, the rotating shaft is sequentially sleeved with end face sealing rings and axial combined sealing rings on the outside of the two ends of the rotor blades. The end face sealing rings and the ends of the rotor blades are squeezed and fitted. An annular tensioning oil chamber is provided in the end cover. The annular tensioning oil chamber can act on the axial combined sealing ring and exert radial centripetal and axial extrusion force toward the rotor blades, so that a rotating seal is formed between the end cover and the rotating shaft.

2. The swing type hydraulic actuator according to claim 1, characterized in that: The axial combined sealing ring includes an annular seal, a wedge ring, and a drum spring which are sequentially sleeved along the radial centrifugal direction. The annular seal and the wedge ring are fitted at a conical surface. In the radial direction of the rotating shaft, the drum spring and the annular tensioning oil chamber are arranged opposite to each other and receive the radial action of the annular tensioning oil chamber.

3. The swing type hydraulic actuator according to claim 2, characterized in that: A compression ring is also sleeved outside the annular seal, and the compression ring abuts against the end of the end face sealing ring away from the rotor blades with a conical surface. The compression ring receives the radial centripetal and axial extrusion force of the annular tightening oil chamber toward the rotor blades to squeeze the annular seal and the end face sealing ring.

4. The swing type hydraulic actuator according to claim 2 or 3, characterized in that: One end of the end face sealing ring abuts against the first sealing shoulder of the rotating shaft. The cross-section of the end face sealing ring is an arched structure with an annular compression spring embedded inside. The axial combined sealing ring abuts against the second sealing shoulder of the rotating shaft through a spacer ring. The rotating shaft is connected to the end cover through a bearing, and the bearing abuts against the bearing positioning shoulder of the rotating shaft.

5. The swing type hydraulic actuator according to claim 4, characterized in that: The axial combined sealing ring also includes an O-ring, which is located at one end of the axial combined sealing ring away from the end face sealing ring and abuts against the end cover.

6. The swing type hydraulic actuator according to claim 1, characterized in that: After the rotating shaft is installed on the cylinder body, the cavity is annular, the stator blades divide the annular cavity, and oil ports communicating with the outside are respectively arranged on both sides of the stator blades.

7. The swing type hydraulic actuator according to claim 1 or 6, characterized in that: The stator blades and rotor blades are respectively provided with sealing grooves opened along the axial direction, and blade sealing gaskets are interference-fitted in the sealing grooves. The blade sealing gaskets on the stator blades are slidably fitted with the outer circumferential surface of the rotating shaft, and the blade sealing gaskets on the rotor blades are slidably fitted with the inner circumferential surface and end surface of the inner wall of the cavity.

8. The swing type hydraulic actuator according to claim 7, characterized in that: The ends of the rotor blades at the connection positions with the rotating shaft are respectively provided with arc-shaped notches, and one end of the end face sealing ring is filled in the arc-shaped notch to form a seal.

9. The swing type hydraulic actuator according to claim 1, characterized in that: The annular tensioning oil chambers are spaced apart upwardly from the end cover ring, and adjacent annular tensioning oil chambers are connected via damping oil chambers. The cross-sectional area of ​​the damping oil chamber is smaller than that of the annular tensioning oil chamber to reserve deformation space.

10. The swing type hydraulic actuator according to claim 1 or 9, characterized in that: The annular tensioning oil chamber is connected to the regulating hole through the oil passage. The regulating hole is equipped with a pressure regulating screw plug. The pressure regulating screw plug can change the relative position with the regulating hole to change the pressure in the oil passage and the annular tensioning oil chamber.

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