Test fixture for electrical high-voltage equipment

Abstract

The invention discloses a test fixture for electrical high-voltage equipment, and relates to the technical field of electrical high-voltage equipment test, two sliding chutes are arranged in parallel on a workbench, one sliding chute is connected with a clamping mechanism in a sliding manner, and the other sliding chute is connected with an electrical detection mechanism in a sliding manner; the clamping mechanism is assembled on one sliding groove in a sliding mode through a first sliding block, a first base plate is arranged above the first sliding block, a first lead screw lifting machine is arranged on the first base plate, a first rotating air cylinder is arranged on the first lead screw lifting machine, a second lead screw lifting machine is transversely arranged on the first rotating air cylinder, and a pneumatic finger is assembled at the tail end of the second lead screw lifting machine. The electrical detection mechanism is assembled on one sliding groove in a sliding mode through a second sliding block, a second base plate is arranged above the second sliding block, a third lead screw lifting machine is arranged on the second base plate, and a second rotating air cylinder is arranged on the third lead screw lifting machine. Compared with the prior art, the device has the advantages that the test accuracy is improved, the connection firmness is enhanced, automatic adjustment is realized, and the device has a protection function.

Description

Technical Field

[0001] This invention relates to the field of electrical high-voltage equipment testing technology, specifically to a testing fixture for electrical high-voltage equipment. Background Technology

[0002] In the electrical field, high-voltage electrical testing is a crucial step in verifying the insulation performance of electrical equipment. The connection method between the high-voltage output conductor and the test object, as an important component of the testing system, plays a vital role in the entire testing process.

[0003] Currently, in electrical high-voltage equipment testing, the traditional connection method mostly uses ordinary alligator clamps to directly fix the conductor and the test object. This connection method has many drawbacks: (1) The accuracy of the test is affected: During the test, the connection between the ordinary alligator clamp and the conductor and the test object is prone to partial discharge. The electromagnetic interference generated by partial discharge will interfere with the electrical signals collected by the test, thus affecting the accuracy of the test results to a certain extent, making the test data unable to truly reflect the insulation performance of the electrical equipment. (2) Poor connection firmness: The clamping force of ordinary alligator clamps is limited, and the structural design is relatively simple. During the test, especially when the test voltage is high, the current is large, or the equipment vibration is large, the clamp and the test object are prone to loosening or even disconnection. This unstable connection will not only lead to test interruption and affect test efficiency, but may also cause dangerous situations such as arc discharge, which will seriously threaten the personal safety of the test personnel and the test equipment. (3) Lack of automated adjustment function: The traditional connection method requires manual installation and adjustment of the clamp. For products of different sizes, it is impossible to achieve fast and accurate adjustment of the connection position. This not only increases the difficulty and labor intensity of the experiment, but also makes it difficult to guarantee the accuracy and consistency of each connection, further affecting the reliability of the test results.

[0004] With the continuous development of the electrical industry, the requirements for the accuracy and safety of electrical high-voltage equipment testing are becoming increasingly stringent. Traditional connection methods are no longer sufficient to meet the needs of modern testing. Therefore, the development of a new type of electrical high-voltage equipment testing fixture is of great practical significance. Summary of the Invention

[0005] The purpose of this invention is to provide a test fixture for high-voltage electrical equipment to solve the problems of poor test accuracy, poor connection firmness, and lack of automatic adjustment function in the existing connection methods, thereby improving the efficiency and safety of high-voltage electrical equipment testing and ensuring the accuracy and reliability of test results.

[0006] Specifically, the technical solution provided by this invention is: a test fixture for high-voltage electrical equipment, comprising:

[0007] The workbench has two parallel sliding grooves. A clamping mechanism is slidably connected to one groove, and an electrical testing mechanism is slidably connected to the other groove. A protective cover is installed on the upper part of the workbench.

[0008] The protective cover has a loading port at the rear and a retrieval door at the front connected by a hinge. A camera is installed inside the protective cover. Multiple conduit ports are installed on the side facades of the protective cover.

[0009] The clamping mechanism is slidably mounted on a slide groove via a first slider. A first base plate is provided above the first slider. A first screw jack is provided on the first base plate. A first rotary cylinder is provided on the first screw jack. A second screw jack is horizontally placed on the first rotary cylinder. A pneumatic finger is provided at the end of the second screw jack.

[0010] An electrical testing mechanism is slidably mounted on a slide groove via a second slider. A second base plate is provided above the second slider. A third screw jack is provided on the second base plate. A second rotary cylinder is provided on the third screw jack. A fourth screw jack is horizontally placed on the second rotary cylinder. A standard test connector is provided at the end of the fourth screw jack.

[0011] The driving mechanism includes a drive motor, which is connected to the first slider and the second slider respectively to realize the sliding of the clamping mechanism and the electrical detection mechanism on the corresponding slide groove.

[0012] Preferably, the workbench is equipped with support legs at the bottom, and the bottom of the support legs is equipped with rubber anti-slip textured pads.

[0013] Preferably, the bottom of the protective cover is fixedly connected to the workbench by screws. The protective cover has a cuboid structure. The rear of the protective cover is provided with a parting port that connects with the production line conveyor belt, and the front is provided with a parting door for removing faulty products.

[0014] Preferably, a camera is provided at the upper corner of the protective cover, and the camera includes two cameras arranged diagonally.

[0015] Preferably, a first lead screw nut is welded to the bottom of the first slider, and a first base plate is welded to the top. A first lead screw jack is vertically fixed on the first base plate. A first lifting platform is assembled at the end of the first lead screw jack. A first rotating cylinder is fixed on the first lifting platform by a positioning pin. A first rotating platform is rotatably connected to the first rotating cylinder. A second lead screw jack is horizontally fixed on the first rotating platform by screws.

[0016] Preferably, the end of the second screw jack is equipped with a second lifting platform, and a pneumatic finger is fixed on the second lifting platform by a positioning pin; the CDA tubes of the first rotating cylinder and the pneumatic finger extend from the conduit port and connect to the matching CDA supply equipment.

[0017] Preferably, a second lead screw nut is welded to the bottom of the second slider, and a second base plate is welded to the top. A third lead screw jack is vertically fixed on the second base plate. A third lifting platform is assembled at the end of the third lead screw jack. A second rotating cylinder is fixed on the third lifting platform by a positioning pin. A second rotating platform is rotatably connected to the second rotating cylinder. A horizontally placed fourth lead screw jack is fixed on the second rotating platform by screws.

[0018] Preferably, the end of the fourth screw jack is equipped with a fourth lifting platform, on which a snakeskin tube is fixed. The snakeskin tube contains a power transmission line, one end of which is equipped with a standard test connector, and the other end extends from the conduit port to connect to the power supply equipment. The CDA tube of the second rotating cylinder also extends from the corresponding conduit port to connect to the matching CDA supply equipment.

[0019] Preferably, the motor shaft of the drive motor is connected to a gear commutator via a coupling, and a drive shaft is rotatably mounted on both sides of the gear commutator. One drive shaft is rotatably connected to the first lead screw seat, and the other drive shaft is rotatably connected to the second lead screw seat.

[0020] Preferably, the first lead screw seat is equipped with a first ball screw, and the first lead screw nut is slidably mounted on the first ball screw; the second lead screw seat is equipped with a second ball screw, and the second lead screw nut is slidably mounted on the second ball screw; the gear commutator is an SPL spiral bevel gear commutator.

[0021] Compared with the prior art, the advantages of this invention are: (1) Improved test accuracy: This invention uses pneumatic fingers and standard test connectors for connection, avoiding the partial discharge phenomenon generated when connecting with traditional alligator clamps, reducing the influence of electromagnetic interference on the test signal, thereby improving the accuracy of the test results and more realistically reflecting the insulation performance of electrical equipment. (2) Enhanced connection firmness: The pneumatic fingers achieve clamping action through air pressure drive, with large and stable clamping force, which can effectively prevent loosening or disconnection during the test. At the same time, the fastening method of the standard test connector and the high voltage end of the product under test is also more firm and reliable, ensuring the safety of the test process. (3) Automated adjustment: By setting multiple screw jacks and rotating cylinders, combined with the feedback signals from the camera and the back-end control system, the test fixture of this invention can automatically adjust the position and angle of the clamping mechanism and the electrical testing mechanism according to the size of the product under test, realizing the automation and precision of the connection process, reducing the difficulty of operation and labor intensity, and improving the test efficiency. (4) Protective function: The protective cover can not only effectively prevent electric arcs, sparks and other hazards generated during the test from causing harm to the surrounding environment and personnel, but also reduce the interference of external factors on the test. At the same time, the design of the retrieval door makes it convenient to remove unqualified products after the test, which improves the convenience of operation. Attached Figure Description

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the workbench of the present invention.

[0025] Figure 3 This is a schematic diagram of the clamping mechanism of the present invention.

[0026] Figure 4 This is a schematic diagram of the electrical testing mechanism of the present invention.

[0027] Figure 5 This is a schematic diagram showing the connection between the clamping mechanism, the electrical detection mechanism, and the drive mechanism of the present invention.

[0028] Figure 6 This is a schematic diagram of the drive mechanism of the present invention.

[0029] As shown in the figure: 1. Workbench; 101. Support leg; 102. Slide groove; 2. Protective cover; 201. Picking door; 202. Placing port; 203. Conduit port; 3. Clamping mechanism; 301. First lead screw nut; 302. First slider; 303. First base plate; 304. First lead screw jack; 305. First lifting platform; 306. First rotary cylinder; 307. First rotary platform; 308. Second lead screw jack; 309. Second lifting platform; 310. Pneumatic finger; 4. Electrical testing mechanism; 401. Second lead screw nut 402. Second slider; 403. Second base plate; 404. Third screw jack; 405. Third lifting platform; 406. Second rotary cylinder; 407. Second rotary platform; 408. Fourth screw jack; 409. Fourth lifting platform; 410. Snake-skin hose; 411. Standard test connector; 5. Drive mechanism; 501. Drive motor; 502. Gear commutator; 503. Drive shaft; 504. First screw seat; 505. First ball screw; 506. Second screw seat; 507. Second ball screw; 6. Camera. Detailed Implementation

[0030] Example 1

[0031] like Figures 1 to 6As shown, this embodiment provides a test fixture for high-voltage electrical equipment. The workbench 1 serves as the main support for the entire test fixture, and its bottom is provided with support feet 101. The bottom of the support feet 101 has rubber anti-slip textured pads, which play a role in stabilizing support and preventing slippage. Two parallel sliding grooves 102 are arranged on the workbench 1. One sliding groove 102 is slidably connected to the clamping mechanism 3 through the first slider 302, and the other sliding groove 102 is slidably connected to the electrical testing mechanism 4 through the second slider 402, providing a track for the movement of the clamping mechanism 3 and the electrical testing mechanism 4. A protective cover 2 is installed on the upper part of the workbench 1 to protect the test process and personnel safety.

[0032] The protective cover 2 has a loading port 202 at the rear, which connects to the production line conveyor belt to allow the product to be inspected to enter the protective cover 2 smoothly; the front is connected to the retrieval door 201 via a hinge, which facilitates the removal of unqualified products after inspection; the protective cover 2 is equipped with two cameras 6 arranged diagonally at the upper corner of the protective cover 2 to capture image information of the product to be inspected; the side of the protective cover 2 is equipped with multiple conduit ports 203 for the extension and connection of the CDA tubes and transmission lines of the pneumatic finger 310, the second rotating cylinder 406, etc. to the supporting equipment; the bottom of the protective cover 2 is fixed to the workbench 1 with screws, which has a cuboid structure and serves to protect and isolate the test environment.

[0033] The clamping mechanism 3 is slidably mounted on a slide groove 102 via a first slider 302. A first lead screw nut 301 is welded to the bottom of the first slider 302, and a first base plate 303 is welded to the top. A first lead screw jack 304 is vertically fixed on the first base plate 303. A first lifting platform 305 is mounted at the end of the first lead screw jack 304. A first rotating cylinder 306 is fixed to the first lifting platform 305 by a positioning pin. A first rotating table 307 is rotatably connected to the first rotating cylinder 306. A horizontally positioned second lead screw jack 308 is fixed to the first rotating table 307 by screws. A second lifting platform 308 is mounted at the end of the second lead screw jack 308. 09. A pneumatic finger 310 is fixed on the second lifting platform 309 by a positioning pin; the CDA tubes of the first rotating cylinder 306 and the pneumatic finger 310 extend from the conduit port 203 and connect to the matching CDA supply equipment; the clamping mechanism 3 moves under the drive of the drive mechanism 5 through the cooperation of various components, and can make fine adjustments to the height and width position by the first screw jack 304 and the second screw jack 308 according to the size and specification signal of the product to be inspected fed back by the camera 6. The first rotating cylinder 306 drives the first rotating platform 307 to rotate so as to realize the fine adjustment of the gripping angle of the pneumatic finger 310 on the plane, and finally the pneumatic finger 310 grips the product.

[0034] The electrical testing mechanism 4 is slidably mounted on a slide groove 102 via a second slider 402. A second lead screw nut 401 is welded to the bottom of the second slider 402, and a second base plate 403 is welded to the top. A third lead screw jack 404 is vertically fixed on the second base plate 403. A third lifting platform 405 is mounted at the end of the third lead screw jack 404. A second rotary cylinder 406 is fixed to the third lifting platform 405 by a positioning pin. A second rotary table 407 is rotatably connected to the second rotary cylinder 406. A horizontally positioned fourth lead screw jack 408 is fixed to the second rotary table 407 by screws. A fourth lifting platform 409 is mounted at the end of the fourth lead screw jack 408. A snake is fixed on the fourth lifting platform 409. The hose 410, a flexible conduit 410, contains a power transmission line. One end of the power transmission line is equipped with a standard test connector 411, and the other end extends from the conduit port 203 to connect to the power supply equipment. The CDA tube of the second rotating cylinder 406 also extends from the corresponding conduit port 203 to connect to the matching CDA supply equipment. The electrical testing mechanism 4 moves under the drive of the drive mechanism 5. After the clamping mechanism 3 places the product into the preset testing position, the standard test connector 411 is adjusted to a suitable height by the third screw jack 404 and the fourth screw jack 408. The third screw jack 404 descends and drives the standard test connector 411 to move vertically downward until it is engaged with the high-voltage end of the product to be tested, and the power supply is started to complete the test.

[0035] The drive mechanism 5 includes a drive motor 501. The motor shaft of the drive motor 501 is connected to a gear commutator 502 via a coupling. Both sides of the gear commutator 502 are rotatably mounted with drive shafts 503. One drive shaft 503 is rotatably connected to a first lead screw seat 504, and the other drive shaft 503 is rotatably connected to a second lead screw seat 506. The first lead screw seat 504 is equipped with a first ball screw 505, and a first lead screw nut 301 is slidably mounted on the first ball screw 505. The second lead screw seat 506 is equipped with a second ball screw 507. The second lead screw nut 401 is slidably mounted on the second ball screw 507; the gear commutator 502 is an SPL spiral bevel gear commutator; the drive mechanism 5 drives the drive motor 501 to rotate forward and backward, and the driving force is transmitted to the drive shafts 503 at both ends after being reversed by the gear commutator 502. The drive shafts 503 drive the first ball screw 505 and the second ball screw 507 to rotate respectively, thereby driving the first lead screw nut 301 and the second lead screw nut 401 to slide, so as to realize the sliding of the clamping mechanism 3 and the electrical detection mechanism 4 on the corresponding slide groove 102.

[0036] Camera 6 is installed at the upper corner of the protective cover 2, with two cameras arranged diagonally. Its function is to capture image information of the product to be inspected and transmit the image data to the back end for calculation. The back end sends a feedback signal on the size and specifications of the product to control the clamping mechanism 3 and the electrical testing mechanism 4 to make corresponding adjustments.

[0037] Based on the above structural features, this embodiment also provides the overall workflow and working principle: When the product to be inspected is conveyed to the placement port 202 by the production line conveyor belt, the two cameras 6 inside the protective cover 2 start working to capture image information of the product to be inspected. The cameras 6 transmit the collected image data to the back-end control system for calculation and analysis.

[0038] The back-end control system sends a feedback signal on the product size and specifications based on the calculation results, controlling the drive motor 501 to reverse. The driving force is transmitted to the gear commutator 502 via the coupling, and the gear commutator 502 reverses the power and transmits it to the drive shafts 503 at both ends. One drive shaft 503 drives the first ball screw 505 to rotate. Since the first screw nut 301 is slidably mounted on the first ball screw 505, and the first screw nut 301 is welded to the first slider 302, which is connected to the clamping mechanism 3, the rotation of the first ball screw 505 causes the first screw nut 301 to slide along the first ball screw 505, thereby driving the upper clamping mechanism 3 to move towards the placement port 202.

[0039] During the movement of the clamping mechanism 3, based on the product size and specification signal fed back from the back end, the first screw jack 304 and the second screw jack 308 begin to operate. The first screw jack 304 drives the first lifting platform 305 to move up and down through its own lifting motion, thereby adjusting the overall height of the clamping mechanism 3; the second screw jack 308 drives the second lifting platform 309 to move left and right through its horizontal lifting motion, achieving fine-tuning of the clamping mechanism 3's position in the width direction. Simultaneously, the first rotary cylinder 306 operates, driving the first rotary table 307 to rotate, thereby achieving fine-tuning of the gripping angle of the pneumatic fingers 310 on the plane. When the clamping mechanism 3 reaches the appropriate position, the pneumatic fingers 310 open and clamp the product to be inspected under air pressure.

[0040] After the clamping mechanism 3 clamps the product to be inspected, the drive motor 501 rotates forward, and the driving force is transmitted through the same path as above, causing the first ball screw 505 to rotate in the opposite direction, driving the clamping mechanism 3 to place the gripped product on the preset detection position on the worktable 1. At the same time, another transmission shaft 503 drives the second ball screw 507 to rotate. Since the second screw nut 401 is slidably mounted on the second ball screw 507, and the second screw nut 401 is welded to the second slider 402, which is connected to the electrical detection mechanism 4, the rotation of the second ball screw 507 causes the second screw nut 401 to slide along the second ball screw 507, thereby driving the upper electrical detection mechanism 4 to move towards the preset detection position.

[0041] Once the electrical testing mechanism 4 reaches the preset position, the third screw jack 404 and the fourth screw jack 408 begin operation. The third screw jack 404 moves the third lifting platform 405 up and down through its own lifting motion, while the fourth screw jack 408 moves the fourth lifting platform 409 left and right through its horizontal lifting motion, adjusting the standard test connector 411 to a suitable height. Then, the third screw jack 404 continues to descend, moving the standard test connector 411 vertically downwards until it engages with the high-voltage end of the product under test. At this point, the power supply equipment connected to the other end of the power line connecting the standard test connector 411 starts, supplying power to the product under test and initiating electrical testing.

[0042] During the testing process, relevant test data is transmitted in real time to the back-end control system for analysis and processing. If the test result shows that the product is qualified, after the test is completed, the drive mechanism 5 drives the clamping mechanism 3 and the electrical testing mechanism 4 to reset, waiting for the next product to be inspected. If the test result shows that the product is unqualified, after the test is completed and the equipment is reset, the operator can open the pick-up door 201, take the unqualified product out of the protective cover 2, and then close the pick-up door 201. The equipment continues to wait for the next product to be inspected to enter for a new round of testing.

[0043] In summary, this electrical high-voltage equipment test fixture can achieve efficient and accurate testing of electrical high-voltage equipment, while ensuring the safety of operators and the stable operation of the test equipment.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A test fixture for high-voltage electrical equipment, characterized in that... include: The workbench (1) has two parallel slides (102) on it. A clamping mechanism (3) is slidably connected to one slide (102), and an electrical testing mechanism (4) is slidably connected to the other slide (102). A protective cover (2) is installed on the upper part of the workbench (1). The protective cover (2) has a loading port (202) at the rear and a loading door (201) at the front connected by a hinge. A camera (6) is installed inside the protective cover (2). Multiple conduit ports (203) are installed on the side of the protective cover (2). A clamping mechanism (3) is slidably mounted on a slide groove (102) via a first slider (302). A first base plate (303) is provided above the first slider (302). A first screw jack (304) is provided on the first base plate (303). A first rotary cylinder (306) is provided on the first screw jack (304). A second screw jack (308) is horizontally placed on the first rotary cylinder (306). A pneumatic finger (310) is provided at the end of the second screw jack (308). An electrical testing mechanism (4) is slidably mounted on a slide groove (102) via a second slider (402). A second base plate (403) is provided above the second slider (402). A third screw jack (404) is provided on the second base plate (403). A second rotary cylinder (406) is provided on the third screw jack (404). A fourth screw jack (408) is horizontally placed on the second rotary cylinder (406). A standard test connector (411) is assembled at the end of the fourth screw jack (408). The driving mechanism (5) includes a driving motor (501), which is connected to the first slider (302) and the second slider (402) respectively, so as to realize the sliding of the clamping mechanism (3) and the electrical detection mechanism (4) on the corresponding slide groove (102).

2. The test fixture for high-voltage electrical equipment according to claim 1, characterized in that: The workbench (1) is provided with a support foot (101) at the bottom, and the support foot (101) is provided with a rubber anti-slip textured pad at the bottom.

3. The test fixture for high-voltage electrical equipment according to claim 1, characterized in that: The bottom of the protective cover (2) is fixedly connected to the workbench (1) by screws. The protective cover (2) has a rectangular structure. The rear of the protective cover (2) is provided with a loading port (202) that is connected to the production line conveyor belt, and the front is provided with a loading door (201) for taking out faulty products.

4. The test fixture for high-voltage electrical equipment according to claim 3, characterized in that: The protective cover (2) is provided with a camera (6) at the upper corner. The camera (6) includes two cameras arranged diagonally.

5. The test fixture for high-voltage electrical equipment according to claim 1, characterized in that: The first slider (302) has a first lead screw nut (301) welded to its bottom and a first base plate (303) welded to its top. A first lead screw jack (304) is vertically fixed on the first base plate (303). A first lifting platform (305) is assembled at the end of the first lead screw jack (304). A first rotating cylinder (306) is fixed on the first lifting platform (305) by a positioning pin. A first rotating table (307) is rotatably connected to the first rotating cylinder (306). A second lead screw jack (308) is horizontally fixed on the first rotating table (307) by screws.

6. A test fixture for high-voltage electrical equipment according to claim 1 or 5, characterized in that: The second screw jack (308) is equipped with a second lifting platform (309) at its end. A pneumatic finger (310) is fixed on the second lifting platform (309) by a positioning pin. The CDA tubes of the first rotating cylinder (306) and the pneumatic finger (310) extend from the conduit port (203) and connect to the matching CDA supply equipment.

7. The test fixture for high-voltage electrical equipment according to claim 1, characterized in that: The second slider (402) is welded with a second screw nut (401) at the bottom and a second base plate (403) at the top. A third screw jack (404) is vertically fixed on the second base plate (403). A third lifting platform (405) is assembled at the end of the third screw jack (404). A second rotating cylinder (406) is fixed on the third lifting platform (405) by a positioning pin. A second rotating table (407) is rotatably connected to the second rotating cylinder (406). A horizontally placed fourth screw jack (408) is fixed on the second rotating table (407) by screws.

8. A test fixture for high-voltage electrical equipment according to claim 1 or 7, characterized in that: The fourth screw jack (408) is equipped with a fourth lifting platform (409) at its end. A snakeskin tube (410) is fixed on the fourth lifting platform (409). A power transmission line is wrapped inside the snakeskin tube (410). One end of the power transmission line is equipped with a standard test connector (411), and the other end extends out from the conduit port (203) to connect to the power supply equipment. The CDA tube of the second rotating cylinder (406) also extends out from the corresponding conduit port (203) to connect to the matching CDA supply equipment.

9. A test fixture for high-voltage electrical equipment according to claim 1, characterized in that: The motor shaft of the drive motor (501) is connected to a gear commutator (502) via a coupling. Both sides of the gear commutator (502) are rotatably equipped with drive shafts (503). One drive shaft (503) is rotatably connected to the first lead screw seat (504), and the other drive shaft (503) is rotatably connected to the second lead screw seat (506).

10. A test fixture for high-voltage electrical equipment according to claim 5, 7, or 9, characterized in that: The first lead screw seat (504) is equipped with a first ball screw (505), and the first lead screw nut (301) is slidably mounted on the first ball screw (505); the second lead screw seat (506) is equipped with a second ball screw (507), and the second lead screw nut (401) is slidably mounted on the second ball screw (507); the gear commutator (502) is an SPL spiral bevel gear commutator.

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