Electro-hydraulic push rod mounting member and electro-hydraulic push rod

Abstract

The application belongs to the technical field of electro-hydraulic push rods, and particularly relates to an electro-hydraulic push rod mounting component and an electro-hydraulic push rod, which comprise a shell, an oil supply mechanism, a speed regulating mechanism and a hydraulic cylinder mounted in the shell, the speed regulating mechanism is used for connecting the oil supply mechanism and the hydraulic cylinder, and comprises a rotary body and a fixed body in sealing rotary connection; the rotary body is provided with an arc-shaped first hydraulic groove and a second hydraulic groove on the surface, the groove depths of the two grooves gradually decrease from one end to the other end, the rotary body is rotated to adjust the oil flow into the rod cavity and the rodless cavity of the hydraulic cylinder by changing the position of the oil inlet corresponding to the groove depth, the waist-shaped hole structure is matched to ensure that the oil passage is smooth at each angle, the flow change into the rod cavity and the rodless cavity is smooth and stepless, the accuracy and stability of the piston rod movement speed adjustment are ensured.

Description

Technical Field

[0001] This invention relates to the field of electro-hydraulic actuator technology, and more particularly to an electro-hydraulic actuator mounting component and an electro-hydraulic actuator. Background Technology

[0002] Electro-hydraulic actuators are a new type of flexible transmission mechanism that integrates mechanical, electrical, and hydraulic technologies. They are mainly composed of hydraulic cylinders, control mechanisms, oil pumps, and motors. Their working principle is as follows: the electric motor drives the bidirectional hydraulic pump to output pressure oil in both directions through forward and reverse rotation. The oil is then sent to the hydraulic cylinder through the hydraulic control valve to realize the reciprocating motion of the piston rod.

[0003] In practical applications of electro-hydraulic actuators, the movement speed of the piston rod needs to be adjusted according to different working conditions. The speed adjustment is essentially achieved by controlling the flow rate of hydraulic oil entering the rod chamber and rodless chamber of the hydraulic cylinder. Existing electro-hydraulic actuator speed adjustment methods use speed control valves, which are usually located on an integrated block inside the oil tank. If the operator needs to adjust the speed, they must first open the oil tank cover and manually turn the valve in the limited internal space. This not only results in a narrow operating space and obstructed vision, but also often requires repeated trial and error, making it difficult to quickly reach the target speed value, leading to low adjustment efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an electro-hydraulic actuator mounting component and an electro-hydraulic actuator, which adjusts the oil inlet speed of the hydraulic cylinder through a speed regulating mechanism, aiming to solve the problems in the prior art.

[0005] To achieve the above-mentioned technical objectives, the specific technical solution of the present invention is as follows: The present invention proposes an electro-hydraulic actuator, including a housing, and an oil supply mechanism, a speed regulating mechanism, and a hydraulic cylinder installed in the housing; the speed regulating mechanism is used to connect the oil supply mechanism and the hydraulic cylinder; the speed regulating mechanism includes a rotating body and a fixed body; the rotating body is configured to be rotatably connected to the fixed body in a sealed manner, and its own rotation can regulate the speed at which hydraulic oil enters the rod-side and rodless-side chambers of the hydraulic cylinder.

[0006] Preferably, the surface of the rotating body is provided with an arc-shaped first hydraulic groove and a second hydraulic groove. Both the first hydraulic groove and the second hydraulic groove are configured such that the groove depth gradually decreases from one end to the other, so that the flow rate of hydraulic oil from one end of the groove to the other end gradually decreases.

[0007] Preferably, the first hydraulic groove is provided with a first oil outlet hole facing the axis of the rotating body at one end near the shallow groove, and the first oil outlet hole is used to communicate with the oil inlet of the rodless chamber of the hydraulic cylinder; the second hydraulic groove is provided with a second oil outlet hole facing the end face of the rotating body at one end near the shallow groove, and is used to deliver hydraulic oil to the rod chamber of the hydraulic cylinder.

[0008] Preferably, the fixing body is provided with a static oil hole that communicates with the second oil outlet hole, and the static oil hole is connected to the oil inlet of the rod chamber of the hydraulic cylinder through an oil pipe.

[0009] Preferably, the first oil outlet is configured as an oblong hole structure that is always connected to the oil inlet of the rodless chamber of the hydraulic cylinder, and the second oil outlet is also configured as an oblong hole structure that is always connected to the static oil hole.

[0010] Preferably, one end of the rotating body is fixedly connected to a rotating frame, and a speed regulating disk is coaxially connected to the rotating frame. The speed regulating disk is located outside the housing and is locked and fixed by a locking nut.

[0011] Preferably, the housing contains an oil tank and a sleeve, the speed regulating mechanism and the hydraulic cylinder are installed inside the sleeve and located around the hydraulic cylinder, a pair of first sealing rings are provided on both sides of the first hydraulic groove and the second hydraulic groove for sealing between the rotating body and the sleeve; a pair of second sealing rings are provided on both sides of the oil inlet of the rodless chamber of the hydraulic cylinder for sealing between the rotating body and the hydraulic cylinder; a third sealing ring is provided between the fixed body and the sleeve and the hydraulic cylinder, and a pair of oil inlet holes are provided on the sleeve that are respectively connected to the first hydraulic groove and the second hydraulic groove.

[0012] Preferably, the sleeve is provided with a retaining ring for positioning the fixed body, the retaining ring is provided with a locking block, and the fixed body is provided with a locking groove that cooperates with the locking block; the end face of the rotating body is provided with a limiting groove, and the end face of the fixed body is provided with a limiting block that slides with the limiting groove.

[0013] Preferably, the oil supply mechanism includes a motor, a coupling, an oil pump, and an integrated block, with the integrated block connected to a pair of oil outlet pipes.

[0014] The present invention also proposes an installation component, comprising: a connecting piece fixedly connected to the housing; and a mounting frame rotatably connected to the connecting piece, the mounting frame being provided with a U-shaped frame.

[0015] The beneficial effects of this invention are as follows: 1. The first and second hydraulic grooves of the present invention adopt an arc-shaped groove structure with the groove depth gradually decreasing from one end to the other. The rotation of the rotating body can realize the continuous gradual change of the flow area. Combined with the waist-shaped hole structure, the oil passage is unobstructed at all angles, so that the flow rate entering the rod chamber and the rodless chamber changes smoothly and is steplessly adjustable, thus ensuring the accuracy and stability of the piston rod movement speed adjustment.

[0016] 2. The speed regulating mechanism of the present invention is directly set on the periphery of the hydraulic cylinder. The first hydraulic groove and the second hydraulic groove on the rotating body are directly connected to the oil inlet of the rod chamber and the rodless chamber of the hydraulic cylinder through the waist-shaped hole structure, respectively. The path of the hydraulic oil from the speed regulating outlet to the working chamber of the hydraulic cylinder is extremely short, the volume effect is small, and the speed regulation accuracy is high. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the electro-hydraulic actuator proposed in this invention.

[0019] Figure 3 This is a schematic diagram of the shell structure proposed in this invention.

[0020] Figure 4 This is a schematic diagram of the speed regulating mechanism proposed in this invention.

[0021] Figure 5 This is a second-angle schematic diagram of the speed regulating mechanism proposed in this invention.

[0022] Figure 6 This is a schematic diagram of the speed regulating mechanism proposed in this invention from a third angle.

[0023] Figure 7 This is a schematic diagram of the installation component proposed in this invention.

[0024] The corresponding names of the attached figures are as follows: 1. Housing; 2. Oil supply mechanism; 3. Speed ​​regulating mechanism; 4. Hydraulic cylinder; 5. Oil outlet pipe; 6. Oil pipe; 31. Rotating body; 32. Fixed body; 33. Rotating frame; 34. Speed ​​regulating disc; 35. Locking nut; 101. Oil tank; 102. Sleeve; 104. Oil inlet; 105. Retaining ring; 103. Clamping block; 311. First hydraulic groove; 312. Second hydraulic groove; 313. Limiting groove; 314. Second oil outlet; 315. First oil outlet; 321. Limiting block; 322. Static oil hole; 323. Clamping groove; 701. Connecting piece; 702. Mounting bracket; 703. U-shaped bracket. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] like Figures 1-7 As shown, this embodiment discloses an electro-hydraulic actuator, which mainly includes a housing 1, an oil supply mechanism 2, a speed regulating mechanism 3, and a hydraulic cylinder 4. The housing 1 serves as the overall load-bearing foundation and has an internal mounting cavity. The oil supply mechanism 2 is fixedly installed at one end inside the housing 1 to provide pressurized hydraulic oil. The hydraulic cylinder 4 is installed at the other end inside the housing 1, and its piston rod extends out of the housing as the output end.

[0027] In this embodiment, the speed regulating mechanism 3 is installed in the oil circuit between the oil supply mechanism 2 and the hydraulic cylinder 4 to connect the oil supply mechanism 2 and the hydraulic cylinder 4. The speed regulating mechanism 3 consists of a rotating body 31 and a fixed body 32. The fixed body 32 is fixedly installed inside the housing 1, and the rotating body 31 is connected to one end of the fixed body 32. The rotating body 31 and the fixed body 32 are sealed and rotated together through a precise clearance fit and sealing elements. When an external force drives the rotating body 31 to rotate relative to the fixed body 32 around its own axis, the flow cross section between the oil passage inside the rotating body 31 and the oil port on the fixed body 32 changes, thereby simultaneously regulating the flow speed of the hydraulic oil entering the rod chamber and the rodless chamber of the hydraulic cylinder 4, and realizing stepless adjustment of the push rod extension speed.

[0028] In this embodiment, the specific oil circuit form of the speed regulating mechanism 3 is further defined. An arc-shaped first hydraulic groove 311 and a second hydraulic groove 312 are formed on the outer circumferential surface of the rotating body 31. These two hydraulic grooves are distributed along the circumference of the rotating body and extend in an arc shape. The bottom of the first hydraulic groove 311 and the second hydraulic groove 312 are designed as inclined or curved surfaces, so that the groove depth of each groove gradually decreases from its starting end to its ending end, i.e., one end is deep and the other end is shallow. When hydraulic oil flows in from different groove depths, due to the gradual change in groove depth, the flow cross-sectional area gradually shrinks along the flow direction, generating a throttling effect. As a result, when the hydraulic oil flows from one end of the groove to the other end, the flow rate gradually decreases. By rotating the rotating body, the actual position of the oil inlet corresponding to the groove depth is changed, and the degree of throttling can be changed.

[0029] In this embodiment, the positions and correspondence of the oil outlets of the two hydraulic grooves are further defined. The first hydraulic groove 311 has a first oil outlet 315 radially toward the axis of the rotating body 31 at one end near the shallow groove. The first oil outlet 315 penetrates the wall of the rotating body 31 and is used to directly communicate with the oil inlet of the rodless chamber of the hydraulic cylinder 4. The hydraulic cylinder 4 is provided with a sealing part that cooperates with the rotating body 31. The sealing part is provided with the oil inlet of the rodless chamber. During the rotation of the rotating body 31, the first oil outlet 315 is always in communication with the oil inlet of the rodless chamber, so that the oil flowing through the first hydraulic groove 311 enters the rodless chamber to push the piston out. The second hydraulic groove 312 has a second oil outlet 314 facing the end face of the rotating body 31 at one end near the shallow groove. The second oil outlet 314 is used to guide the oil flowing through the second hydraulic groove 312 to one side of the end face of the rotating body 31. The two oil outlets correspond to oil paths in different directions and do not interfere with each other.

[0030] In this embodiment, the intermediate connection structure of the rod cavity oil circuit is further defined. The fixed body 32 is provided with a static oil hole 322. The static oil hole 322 is a fixed channel that penetrates the wall of the fixed body 32. When the rotating body 31 is assembled with the fixed body 32, the second oil outlet 314 is always connected to the static oil hole 322 on the fixed body 32 during the rotation of the rotating body 31. The outer end interface of the static oil hole 322 is connected to the oil inlet of the rod cavity of the hydraulic cylinder 4 through an oil pipe 6, thereby guiding the hydraulic oil in the second hydraulic groove 312 to the rod cavity through the second oil outlet 314, the static oil hole 322 and the oil pipe 6.

[0031] In this embodiment, the structural shape of the two oil outlet holes is optimized. The first oil outlet hole 315 is set as an oblong hole, with its length direction distributed along the circumference of the rotating body 31. The coverage of the oblong hole is designed such that, throughout the entire rotatable stroke of the rotating body 31, the first oil outlet hole 315 always partially or completely overlaps with the oil inlet of the rodless chamber of the hydraulic cylinder 4, ensuring that the oil inlet of the rodless chamber can continuously supply oil at any speed adjustment angle without interruption due to rotation. Similarly, the second oil outlet hole 314 is also set as an oblong hole structure, with its length direction distributed along the circumference or arc of the end face of the rotating body 31, to ensure that, throughout the entire rotatable stroke of the rotating body 31, the second oil outlet hole 314 always remains connected with the static oil hole 322 on the fixed body 32, ensuring the continuity of oil supply to the rod chamber.

[0032] In this embodiment, the driving structure of the rotating body 31 is further defined. A rotating frame 33 is fixedly connected to one end of the rotating body 31 facing the outside of the housing 1. The rotating frame 33 is coaxially arranged with the rotating body 31 and can be fixed by spline, flat key or welding. The rotating frame 33 extends outward and passes through the end cover of the housing 1. A speed regulating disk 34 is coaxially connected to its outer end. The speed regulating disk 34 is set outside the housing 1 for easy gripping and rotation by the operator. The speed regulating disk 34 is pressed and fixed to the threaded post of the rotating frame 33 by a locking nut 35. When speed adjustment is required, the locking nut 35 is loosened and the speed regulating disk 34 is rotated to drive the rotating frame 33 and the rotating body 31 to rotate synchronously. After the speed is adjusted to the desired position, the locking nut 35 is tightened to lock and prevent the angle from changing due to vibration.

[0033] In this embodiment, the specific layout and sealing structure inside the housing 1 are further defined. The housing 1 is provided with an independent oil tank 101 for storing hydraulic oil, and a cylindrical sleeve 102 is provided. The speed regulating mechanism 3 and the hydraulic cylinder 4 are both installed in the cavity of the sleeve 102, and the speed regulating mechanism 3 is arranged around the hydraulic cylinder 4, that is, the two are coaxially sleeved. The speed regulating mechanism 3 surrounds the outside of the hydraulic cylinder or is arranged along its outer periphery.

[0034] On the outer wall of the rotating body 31, a pair of first sealing rings, such as O-rings or combined sealing rings, are respectively provided on the left and right sides of the first hydraulic groove 311 and the second hydraulic groove 312. The first sealing rings are pressed between the rotating body 31 and the inner wall of the sleeve 102 to prevent the hydraulic oil in the groove from leaking axially to other areas of the sleeve. On both sides of the oil inlet of the rodless chamber of the hydraulic cylinder 4, a pair of second sealing rings are provided, pressed between the rotating body 31 and the outer wall of the hydraulic cylinder 4 to prevent the oil at the oil inlet of the rodless chamber from leaking along the fitting gap. A third sealing ring is provided between the fixed body 32 and the inner wall of the sleeve 102, and between the fixed body 32 and the outer wall of the hydraulic cylinder 4, to ensure that the installation position of the fixed body 32 is reliably sealed. A pair of oil inlet holes 104 are opened on the pipe wall of the sleeve 102. These two oil inlet holes 104 are respectively connected to the positions of the first hydraulic groove 311 and the second hydraulic groove 312. The pressure oil output by the oil supply mechanism 2 enters the corresponding hydraulic groove through these two oil inlet holes 104.

[0035] In this embodiment, the circumferential positioning of the fixed body and the rotation limiting structure of the rotating body are further defined. A retaining ring 105 is fixedly installed on the inner wall of the sleeve 102. The retaining ring 105 is used to axially position the fixed body 32 to ensure the accurate position of the speed regulating mechanism 3. A protruding locking block 103 is provided on the inner side of the retaining ring 105. Correspondingly, a locking groove 323 is opened on the outer circumference of the fixed body 32. During installation, the locking block 103 is inserted into the locking groove 323, thereby restricting the circumferential rotation of the fixed body 32 relative to the sleeve 102 and keeping it in a fixed posture at all times.

[0036] In this embodiment, an arc-shaped limiting groove 313 is provided on the end face of the rotating body 31, and a protruding limiting block 321 is fixedly provided on the end face of the fixed body 32. The limiting block 321 extends into the limiting groove 313 and can slide along the limiting groove. When the rotating body 31 rotates to the limit angle, the limiting block 321 contacts the end wall of the limiting groove 313, thereby limiting the maximum rotation range of the rotating body 31 and preventing excessive rotation from causing oil circuit misalignment or sealing failure.

[0037] In this embodiment, the specific composition of the oil supply mechanism is further defined. The oil supply mechanism 2 includes a motor, a coupling, an oil pump, and an integrated block. The motor serves as a power source and is connected to the input shaft of the oil pump via the coupling to drive the oil pump. The oil pump's suction port is connected to the oil tank 101, and the oil pump's outlet port is connected to the oil passage inside the integrated block. A pair of oil outlet pipes 5 are connected to the integrated block. These two oil outlet pipes are respectively connected to two oil inlet holes 104 on the sleeve 102, and are used to deliver pressurized oil to the first hydraulic tank 311 and the second hydraulic tank 312, respectively. The integrated block may also integrate auxiliary valves such as safety valves and check valves to ensure stable oil supply pressure and direction.

[0038] Working principle of speed regulating mechanism 3: Through the sealed rotational cooperation between rotating body 31 and fixed body 32, the external mechanical rotational motion is directly converted into a continuous and controllable change in the throttling area of ​​the internal oil circuit. The arc-shaped first hydraulic groove 311 and second hydraulic groove 312 on the rotating body are both designed as a gradual structure with the groove depth decreasing from one end to the other. When the rotating body 31 rotates relative to the fixed body, the fixed oil inlet hole 104 will correspond to the groove position of different depths, so that the cross-section of the hydraulic oil changes when it flows from the deep groove end to the shallow groove end, thereby generating a controllable throttling effect and realizing continuous flow regulation. At the same time, the two hydraulic grooves rotate synchronously with the rotating body 31, so that the flow rate entering the rod chamber and rodless chamber of the hydraulic cylinder 4 changes in linkage, ensuring that the extension and retraction speed of the push rod is proportionally and synchronously adjusted, avoiding The problem of bidirectional speed mismatch is solved; both the first oil outlet 315 and the second oil outlet 314 adopt an oblong hole structure, which always maintains communication with the corresponding cavity or static oil hole 322 throughout the entire rotation stroke of the rotating body, ensuring uninterrupted oil supply and preventing hydraulic shock and creep; the limiting block 321 on the fixed body slides with the limiting groove 313 on the rotating body, strictly limiting the speed range and preventing oil circuit misalignment or seal damage due to excessive rotation; the static oil hole 322 cooperates with the second oil outlet 314 on the end face of the rotating body to realize reliable oil circuit conversion between moving and stationary parts, so that the external oil pipe 6 can be fixedly arranged, simplifying the pipeline structure; continuous stepless speed regulation is achieved, which is suitable for industrial application scenarios with high requirements for vibration resistance, explosion protection and maintenance convenience.

[0039] This embodiment provides a specialized mounting component for fixing the electro-hydraulic actuator described in any of the above schemes. The mounting component includes a connecting piece 701, a mounting bracket 702, and a U-shaped bracket 703. The connecting piece 701 is fixedly connected to the outer wall of the housing 1 of the electro-hydraulic actuator by welding. One end of the connecting piece 701 is rotatably connected to the mounting bracket 702 by a pin or a rotating shaft, so that the electro-hydraulic actuator as a whole can pitch and swing relative to the mounting bracket 702 within a certain angle range, which facilitates the adjustment of the output direction to adapt to different installation conditions.

[0040] A U-shaped frame 703 is fixedly connected to the bottom or back of the mounting bracket 702. The U-shaped frame 703 is a U-shaped steel component with an outward opening. Coaxial mounting holes are provided on its two parallel walls for fixing the entire mounting component to the external equipment base or bracket with bolts. The structure of the U-shaped frame 703 provides a stable support surface and a convenient clamping method.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electro-hydraulic actuator, characterized in that, Includes a housing (1), and an oil supply mechanism (2), a speed regulating mechanism (3), and a hydraulic cylinder (4) installed inside the housing (1); The speed regulating mechanism (3) is used to connect the oil supply mechanism (2) and the hydraulic cylinder (4), and includes a rotating body (31) and a fixed body (32). The rotating body (31) is configured to be rotatably connected to the fixed body (32) in a sealed manner, and its rotation can adjust the speed at which hydraulic oil enters the rod-side and rodless-side chambers of the hydraulic cylinder (4).

2. The electro-hydraulic actuator according to claim 1, characterized in that, The surface of the rotating body (31) is provided with an arc-shaped first hydraulic groove (311) and a second hydraulic groove (312). The first hydraulic groove (311) and the second hydraulic groove (312) are both configured such that the groove depth gradually decreases from one end to the other end, so that the flow rate of hydraulic oil from one end of the groove to the other end gradually decreases.

3. The electro-hydraulic actuator according to claim 2, characterized in that, The first hydraulic groove (311) has a first oil outlet (315) facing the axis of the rotating body (31) at one end near the shallow groove. The first oil outlet (315) is used to communicate with the oil inlet of the rodless chamber of the hydraulic cylinder (4). The second hydraulic groove (312) has a second oil outlet (314) facing the end face of the rotating body (31) at one end near the shallow groove. It is used to deliver hydraulic oil to the rod chamber of the hydraulic cylinder (4).

4. An electro-hydraulic actuator according to claim 3, characterized in that, The fixed body (32) is provided with a static oil hole (322) that communicates with the second oil outlet (314). The static oil hole (322) is connected to the oil inlet of the rod chamber of the hydraulic cylinder (4) through the oil pipe (6).

5. An electro-hydraulic actuator according to claim 3, characterized in that, The first oil outlet (315) is configured as an oblong hole structure that is always connected to the oil inlet of the rodless chamber of the hydraulic cylinder (4), and the second oil outlet (314) is also configured as an oblong hole structure that is always connected to the static oil hole (322).

6. An electro-hydraulic actuator according to claim 1, characterized in that, One end of the rotating body (31) is fixedly connected to a rotating frame (33), and a speed regulating disk (34) is coaxially connected to the rotating frame (33). The speed regulating disk (34) is located outside the housing (1) and is locked and fixed by a locking nut (35).

7. An electro-hydraulic actuator according to claim 2, characterized in that, The housing (1) is provided with an oil tank (101) and a sleeve (102). The speed regulating mechanism (3) and the hydraulic cylinder (4) are installed in the sleeve (102) and located on the periphery of the hydraulic cylinder (4). A pair of first sealing rings are provided on both sides of the first hydraulic groove (311) and the second hydraulic groove (312) for sealing between the rotating body (31) and the sleeve (102). A pair of second sealing rings are provided on both sides of the oil inlet of the rodless chamber of the hydraulic cylinder (4) for sealing between the rotating body (31) and the hydraulic cylinder (4). A third sealing ring is provided between the fixed body (32) and the sleeve (102) and the hydraulic cylinder (4). A pair of oil inlet holes (104) are provided on the sleeve (102) and respectively connected to the first hydraulic groove (311) and the second hydraulic groove (312).

8. An electro-hydraulic actuator according to claim 7, characterized in that, The sleeve (102) is provided with a retaining ring (105) for positioning the fixed body (32), and a retaining block (103) is provided on the retaining ring (105). The fixed body (32) is provided with a slot (323) that cooperates with the slot (103). The end face of the rotating body (31) is provided with a limiting groove (313), and the end face of the fixed body (32) is provided with a limiting block (321) that slides with the limiting groove (313).

9. An electro-hydraulic actuator according to claim 1, characterized in that, The oil supply mechanism (2) includes a motor, a coupling, an oil pump and an integrated block, and the integrated block is connected to a pair of oil outlet pipes (5).

10. A mounting component for mounting an electro-hydraulic actuator as described in claim 1, characterized in that, include: A connecting piece (701) is fixedly connected to the housing (1); A mounting bracket (702) is rotatably connected to the connecting piece (701), and a U-shaped bracket (703) is provided on the mounting bracket (702).

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