A swing type hydraulic actuator

Abstract

The present invention provides a swing type hydraulic actuator, which relates to the field of swing hydraulic cylinders. In order to solve the problem that the sealing performance and durability of the current swing hydraulic cylinder sealing structure are relatively poor, a cavity is formed by a cylinder body and a rotating shaft to accommodate stator blades and rotor blades, and the wedge 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 provided on the end cover, and the pressure of the annular tightening oil chamber is adjusted according to the requirements of the working environment, 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 oil cylinder.

Description

Technical Field

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

[0002] Hydraulic swing cylinders achieve a wide range of motion and angle adjustment through output hydraulic pressure, can withstand heavy loads, and provide stable motion control. They are widely used in aerospace, robotics, automation systems, and engineering machinery. Common hydraulic swing cylinders include rack and pinion, spiral, and vane types. Compared to the other two types, vane types offer lower moment of inertia, more agile motion, uniform rotation, and less pulsation. They are also simple to manufacture and less expensive. However, internal dynamic sealing is difficult, resulting in a short seal life, prone to leakage, and low volumetric efficiency, limiting their application in high-pressure environments.

[0003] During operation, a vane-type swing cylinder primarily requires radial sealing between the stator and rotor blades, and end-face rotary sealing between the blades and the rotating shaft. The end-face rotary sealing must prevent both circumferential oil leakage between the blades and leakage from the seal cavity to the external environment, requiring high precision machining and assembly of the seal contact surfaces. The inability to adjust the seal gap during system pressure fluctuations can lead to over-tightening or seal failure, compromising the vane-type swing cylinder's adaptability to environmental conditions. Summary of the Invention

[0004] The purpose of the present invention is to address the defects of the existing technology and provide a swinging hydraulic actuator, 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 provided 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 swinging oil 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. A cavity is formed inside the cylinder body, and end covers of the cylinder body are provided at both ends of the cavity. Rotor blades are provided on the rotating shaft, and stator blades are provided in the cavity. The rotating shaft and the cylinder body rotate in conjunction, and the rotor blades form a sliding seal with the inner wall of the cavity.

[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 are squeezed and fitted to the ends of the rotor blades. 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 to form a rotating seal 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 annular seal and the wedge ring are fitted into 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 pressure ring is provided outside the annular seal, and the pressure ring abuts against the end face sealing ring away from the rotor blade with its conical surface. The pressure ring receives the radial centripetal and axial extrusion force of the annular tightening oil chamber toward the rotor blade 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. 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 further comprises 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 separate 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 face 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 an oil channel, and the regulating hole is equipped with a pressure regulating plug. The pressure regulating plug can change its 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 current sealing structure of the 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 surface of the end face sealing ring and the axial combined sealing ring is used to pre-tighten the two seals; at the same time, an annular tightening oil chamber is set 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 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 equipped with a drum spring to compensate for the sealing gap caused by seal wear, 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, 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 This is an exploded view of the swing type hydraulic actuator in Example 1 of the present invention.

[0022] Figure 2 Schematic cross-sectional view of the swing type hydraulic actuator in Example 1 of the present invention.

[0023] Figure 3 Schematic cross-section 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 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 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, plug rod; 103, pressure regulating head; 201, chamber A; 202, chamber B; 203, oil port A; 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 system pressure changes, 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 by the end cover 9, the cylinder wall 15 and the hollow rotating 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 perform preliminary preload on the two seals. At the same time, an annular tightening oil chamber 901 is provided on the end cover 9. 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 provided on the end face sealing ring 12 and the drum spring 1003 provided on the axial combined seal compensate for the sealing gap caused by seal wear, thereby improving the service life of the end face rotating seal.

[0032] like Figure 1 、 Figure 2 and Figure 3 As shown, this embodiment provides a single-vane oscillating oil cylinder with an adaptive end-face rotary seal, comprising a cylinder body and a rotating shaft. A cavity is formed within the cylinder body, with end caps 9 provided at both ends of the cavity. The main body is the cylinder body, which includes a cylinder wall 15 and two end caps. The rotating shaft rotates in conjunction with the cylinder body, forming a sealed cavity. The rotating shaft utilizes a hollow rotating shaft 13, which can be mounted on or at the end of the output shaft via a keyway without any position restrictions. The installation method is diverse and can adapt to different working environments.

[0033] In the axial direction of the rotating shaft, the rotating shaft is sequentially sleeved with end face sealing rings 12 and axial combined sealing rings 10 on the outside of both 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 apply radial centripetal and axial extrusion force toward the rotor blades 206, so that a rotating seal is formed between the end cover 9 and the rotating shaft.

[0034] like Figure 3 As shown, rotor blades 206 are disposed on the outside of the hollow shaft 13, and stator blades 205 are disposed on the inside of the cylinder wall 15. After the shaft is installed in the cylinder body, the cavity is annular. Stator blades 205 separate the sealed cavity in the shape of ring 11, and oil ports for connecting to the outside are provided on both sides of the stator blades 205. The blades divide the sealed cavity into chamber A 201 and chamber B 202. Oil ports A 203 and B 204 are provided on both sides of the stator blades 205. The oil ports are opened from the sides of the stator blades 205 to provide more direct hydraulic force. During operation of the swing hydraulic actuator, chambers A 201 and B 202 will periodically transform into high-pressure and low-pressure chambers depending on the direction of hydraulic oil injection. The high-pressure chamber oil drives the hollow shaft 13 to rotate toward the low-pressure chamber by pushing the rotor blades 206. A keyway is provided in the hollow portion of the hollow shaft 13 to output torque 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 slide in contact with the outer circumferential surface of the rotating shaft, and the blade sealing gaskets 5 on the rotor blades 206 slide in contact with the inner circumferential surface and end face 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 fit of the hollow shaft 13, the cylinder wall 15 and the end covers 9 on both sides during the assembly process, internal leakage between the A cavity 201 and the B cavity 202 can be prevented. Sealing grooves are provided on the end faces of both sides of the cylinder wall 15, and a first O-ring 14 is provided inside, which is 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 provided 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 with an annular compression spring 1201 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 arranged 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 face sealing ring 12 away from the rotor blade 206 with its 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 blade 206 to squeeze the annular seal 4 and the end face sealing ring 12.

[0039] Specifically, in this 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 installed on the first sealing shaft shoulder 1301, and the end face sealing ring 12 and the hollow rotating shaft 13 are interference fit. The rotation of the hollow rotating shaft 13 simultaneously drives the end face sealing ring 12 to rotate, and the sealing surface of the end face sealing ring 12 in contact with the blade is set to be an arc surface, and the radius is larger than the arc-shaped notch set on the blade sealing gasket 5, to ensure that the end face sealing ring 12 and the blade sealing gasket 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] Close contact is ensured between the pressure ring 4 and the end seal, and the sealing contact surface is tapered, ensuring that the axial compression force of the pressure ring 4 provides the end seal ring 12 with a clamping force toward the axis and a pressing force toward the first sealing shoulder 1301. An annular compression spring 1201 is provided inside the end seal ring 12 to provide initial clamping force, allowing the inner ring of the end seal ring body 1202 to closely contact the outer wall of the hollow shaft 13, reducing axial leakage. At the same time, it can provide a certain degree of compensation for the wear gap when the outer ring of the end seal ring body 1202 wears out after long-term operation.

[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 set 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 limits can prevent the axial combined sealing ring 10 from failing to seal 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 . Multiple wear-reducing grooves are provided on the contact surface between the annular seal 1001 and the hollow rotating shaft 13 to reduce the friction area during rotation and form multiple sealing belts to prevent external leakage of hydraulic oil; the inner conical surface of the wedge ring 1002 presses the outer conical surface of the annular seal 1001. When the end cover 9 is connected to the cylinder wall 15 by 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 provided on the upper end surface of the wedge ring 1002, and a second O-ring 1004 is provided inside to prevent external leakage of hydraulic oil; the outer ring of the wedge ring 1002 is provided with an annular groove, and a drum spring 1003 is provided inside. During the downward squeezing of the wedge ring 1002, the drum-shaped protrusion on the surface of the spring is compressed, generating strain energy, which strengthens the axial clamping force during the axial combined seal rotation friction process. At the same time, when the inner ring of the annular seal 1001 wears after long-term work, it can provide a certain compensation effect for 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 spaced apart in an upward direction on the end cover 9, and adjacent annular tensioning oil chambers 901 are connected through the damping oil chamber 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, such as 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 sets 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 it is connected to the annular tensioning oil chamber 901. The two oil chambers are spaced apart and evenly distributed circumferentially, and the oil chambers are filled with pressure medium.

[0046] Annular tensioning oil chamber 901 is connected to regulating hole 903 via oil passage 904. Regulating hole 903 is equipped with a pressure-regulating plug 1, which can change its relative position with regulating hole 903 to alter the pressure within oil passage 904 and annular tensioning oil chamber 901. Annular tensioning oil chamber 901 deforms in response to the pressure of the medium within it. Damping oil chamber 902 prevents uneven deformation of the inner surface of end cap 9 and more precisely controls pressure changes within the chamber.

[0047] The end cover 9 is provided with an oil passage 904 on the outer side surface connected to 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 formed on the outer end surface of the end cap 9. This adjustment hole 903 can be divided into a threaded hole and a pressure-regulating hole. The adjustment hole 903 connects to the oil passage 904, the annular tensioning oil chamber 901, and the damping oil chamber 902, all of which are filled with pressure medium. A pressure-regulating plug 1 is located within the adjustment hole 903. The pressure-regulating plug 1 comprises a plug rod 102 and a pressure-regulating head 103. The threads on the plug rod 102 mate with the threaded hole, and the pressure-regulating head 103 mates with the pressure-regulating hole. The pressure-regulating head 103 is provided with two sealing grooves 207. A third O-ring 101 is inserted into the sealing grooves 207. The outer diameter of the third O-ring 101 is larger than the pressure-regulating hole, preventing the pressure medium in the oil passage 904 from leaking through the adjustment hole 903.

[0049] Specifically, when the pressure-regulating screw plug 1 is screwed into the hole, the pressure-regulating head 103 compresses the pressure medium, causing the pressure in the annular expansion oil chamber 901 to increase, causing the inner surface of the end cover 9 to deform, exerting pressure perpendicular to the conical surface on the pressure ring 4, and transmitting the pressure to the end face sealing ring 12 through the pressure ring 4. At the same time, an inward pressing force is exerted on the axial combined seal, increasing the contact pressure between the two sets of seals and the hollow shaft 13, performing secondary pre-tightening, 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-pre-tightening or the occurrence of sealing gaps.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection 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 provided at both ends of the cavity. Rotor blades are provided on the rotating shaft. Stator blades are provided in the cavity. The rotating shaft and the cylinder body rotate in conjunction. 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 outer sides of the rotor blades. The end face sealing rings are squeezed and fitted with the ends of the rotor blades. 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 apply radial centripetal and axial squeezing forces toward the rotor blades, so that a rotating seal is formed between the end cover and the rotating shaft. The axial combined seal ring includes an annular seal, a wedge ring, and a drum spring which are sequentially sleeved in a radial centrifugal direction. The annular seal and the wedge ring are in contact with each other at a conical surface. In the radial direction of the rotating shaft, the drum spring is arranged opposite to the annular tensioning oil chamber and receives the radial action of the annular tensioning oil chamber. A pressure ring is also provided outside the annular seal, and the pressure ring abuts against the end face sealing ring away from the rotor blade with its conical surface. The pressure ring receives the radial centripetal and axial extrusion force of the annular tightening oil chamber toward the rotor blade to squeeze the annular seal and the end face sealing ring.

2. The swing type hydraulic actuator according to claim 1, 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, 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. 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.

3. The swing type hydraulic actuator according to claim 2, characterized in that: The axial combined sealing ring further comprises 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.

4. 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 separate the annular cavity, and oil ports communicating with the outside are respectively provided on both sides of the stator blades.

5. The swing type hydraulic actuator according to claim 1 or 4, 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 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.

6. The swing type hydraulic actuator according to claim 5, 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.

7. 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.

8. The swing type hydraulic actuator according to claim 1 or 7, characterized in that: The annular tensioning oil chamber is connected to the regulating hole through the oil channel. The regulating hole is equipped with a pressure regulating plug. The pressure regulating plug can change its relative position with the regulating hole to change the pressure in the oil channel and the annular tensioning oil chamber.

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