WO2013143415A1

WO2013143415A1 - Electric chassis vehicle for circuit breaker

Info

Publication number: WO2013143415A1
Application number: PCT/CN2013/073009
Authority: WO
Inventors: 汤民; 马尚·F·J; 莱齐亚·B·R; 鲍丽华
Original assignee: 伊顿电气有限公司
Priority date: 2012-03-28
Filing date: 2013-03-21
Publication date: 2013-10-03
Also published as: CN102723676A; CN102723676B

Abstract

An electric chassis vehicle for a circuit breaker comprises a static frame and a movable frame (9) moving relative to the static frame. A lead screw (8) is mounted on the static frame, and a lead screw block (7) fixed to the movable frame (9) is assembled on the lead screw (8). A motor assembly (1) is also mounted on the movable frame (9). Rotation of the motor assembly (1) is transferred to the lead screw (8) through a transmission mechanism so as to drive the lead screw block (7), the movable frame (9), and the motor assembly (1) to move along an axial direction of the lead screw (8). An electromagnetic clutch is mounted between the motor assembly (1) and the transmission mechanism. The electric chassis vehicle for the circuit breaker is of a simple structure and small in size, and has a great carrying capacity.

Description

Circuit breaker electric chassis vehicle

The present invention relates to a circuit breaker chassis vehicle in a power system, and more particularly to a circuit breaker electric chassis vehicle. Background technique

In the existing insulation switch rejection, in order to enable the vacuum circuit breaker to easily realize the propulsion and withdrawal functions (propulsion refers to the advancement from the test position to the working position, the exit refers to the exit from the working position to the test position), generally using one The chassis car carries the vacuum circuit breaker and travels forward or backward through the track wheels mounted on the chassis. In order to realize the movement of the chassis car in the switch rejection, a screw rod may be arranged on the chassis car, and a screw nut fixed on the chassis frame is sleeved on the screw rod, the handle is sleeved on the end of the screw rod, and the screw rod is turned to make the wire The mother drives the chassis frame to move forward and backward, thereby realizing the advancement and withdrawal of the circuit breaker chassis. The chassis is inefficient due to the manual operation of the manual operation handle, which is inconsistent with the development of power automation.

In another type of switch rejection, an electric operation module is added to the chassis, wherein the motor assembly is mounted on the chassis, and the chassis is propelled and retracted by the forward rotation and reverse rotation of the motor assembly, thereby implementing the chassis. The electrification and automation of motor sports is called electric chassis. The electric chassis generally includes a chassis static frame and a chassis moving frame. The chassis assembly is provided with a motor assembly, a clutch and a lead screw. The motor assembly is coupled to the clutch, and the other end of the clutch is coupled to the screw. A manual priority device, a test position switching device, and a work position switching device for safety considerations are also provided on the chassis. The manual priority device has a micro switch and a transmission rod mounted under the micro switch, and the other end of the transmission rod is connected to the screw. When the manual operation is performed, the micro switch on the manual priority device is immediately turned off, and the motor assembly circuit is cut off, so that the electric operation cannot be performed. The motor assembly and the screw in the chassis can be driven by a gear transmission mode, and equipped with a special clutch. When the jam occurs, the clutch is automatically disengaged, the motor assembly is idling, and the current control of the drive module is relied upon. The electric handcart automatically returns to the "test" position. When the motor is operated, the lead screw does not move and the 雉 gear rotates; when it is manually operated, the lead screw rotates and the 雉 gear does not move.

In the prior art, electric chassis vehicles are equipped with mechanical clutches. The disadvantage of the electric chassis vehicle with the mechanical clutch is that, due to the large number of mechanical clutch parts and high processing precision, the electric chassis is large in size and insufficient in reliability. In addition, the size of the electric chassis and its clutch cannot be designed too large due to the limited volume of the switch. At the same time, due to the higher voltage, The insulation requirements for the switch rejection are also high, and the size and weight of the circuit breaker are correspondingly increased. This creates a contradiction between the load capacity of the chassis and the volume limit. For the above reasons, currently only

The 12KV circuit breaker automates the chassis. For a 40.5KV circuit breaker, if a small mechanical clutch is used, it will not be able to transmit enough torque to drive the circuit breaker. If a large mechanical clutch is used, it will not be effectively installed due to the space limitation of the switch. So far, the 40.5KV circuit breaker has not been able to effectively achieve electrification. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit breaker electric chassis vehicle which is simple in structure, compact in size and has a large carrying capacity in view of the above-mentioned drawbacks of the prior art.

The circuit breaker electric chassis truck of the present invention comprises a static frame and a moving frame movable relative to the static frame, wherein the static frame is provided with a screw rod, and the screw is equipped with a fixed fixed to the moving frame a threaded rod block, wherein the motor frame is further equipped with a motor assembly, and the rotation of the motor assembly is transmitted to the screw rod through a transmission mechanism, thereby driving the screw rod block, the moving frame and the motor assembly along the screw rod The axial movement, an electromagnetic clutch is installed between the motor assembly and the transmission mechanism. Since the chassis vehicle successfully uses the electromagnetic clutch as the clutch member for power transmission, the chassis vehicle fully utilizes the advantages of small size and simple structure of the electromagnetic clutch, thereby significantly reducing the required space and completely solving the bearing capacity and space of the chassis. The contradiction between the restrictions, so as to achieve the circuit breaker, especially the 40.5kV voltage level of electrification, created conditions for automatic control, and thus solved the technical problem that the 40.5KV circuit breaker chassis has been unable to implement automatic operation.

Preferably, the electric chassis vehicle of the present invention applies the electromagnetic clutch installation to the chassis chassis of the circuit breaker by the following simple and reliable structure: the transmission mechanism is a chain transmission mechanism, including the output of the motor assembly supported by the bearing a first sprocket on the shaft and a second sprocket axially movably mounted on the lead screw and a drive chain cooperating with the first sprocket and the second sprocket, when working, first The sprocket rotates around the output shaft under the driving of the electromagnetic clutch and drives the second sprocket and the screw to rotate through the transmission chain, while the second sprocket will move axially along the screw. The electromagnetic clutch includes a clutch body and a suction cup, and the clutch body and the suction cup are respectively provided with opposite friction surfaces, and the suction cup is supported on the output shaft of the motor assembly and can be along the motor under the magnetic force of the clutch body. The axial movement of the output shaft of the assembly, wherein the suction cup is always engaged with the first sprocket in a torque transferable manner during axial movement of the suction cup along the output shaft of the motor assembly.

Preferably, the suction cup and the first sprocket are respectively provided on the opposite surfaces to cooperate with each other and resist a first boss and a second boss, the first boss will engage and push the second boss to rotate the first sprocket as the chuck rotates, the engageable surface of the first boss and the second boss along the motor The length of the output shaft of the assembly is greater than the distance of the opposite friction surface of the suction cup and the clutch body along the output shaft of the motor assembly. "Joint surface" refers to the contact surface of the first boss and the second boss when they are joined to each other, which will change as the chuck moves along the output shaft. "The length of the joint surface along the output shaft of the motor assembly" refers to the projected length of the joint surface on the output shaft. When the suction cup moves along the output shaft to the position farthest from the electromagnetic clutch, it has the largest joint surface along the output shaft length of the motor assembly. .

Preferably, the first boss and the second boss are respectively disposed along a circumference of the suction hole and the shaft hole of the first sprocket. The advantage of providing the boss along the periphery of the suction hole and the shaft hole of the first sprocket is that the support of the motor assembly output shaft to the suction cup and the first sprocket is increased, and the overall volume of the suction cup and the first sprocket can be effectively reduced. , which makes it easier to arrange.

Preferably, the suction cup is provided with a friction enhancing structure on the opposite friction surface of the clutch body. The friction enhancing structure is preferably a bump or a ridge.

Preferably, the motor assembly includes a shifting device to convert the motor speed adjustment to the operating speed required for the particular operating environment of the circuit breaker chassis.

Preferably, the electric chassis vehicle further includes a control system, and the starting and stopping of the motor assembly and the clutching of the electromagnetic clutch are both controlled by the control system. Wherein, the control system preferably includes a moving end position switch of the moving frame, the moving end position switch is a normally closed switch, and the normally closed switch transmits a signal to the control system to stop the motor assembly when the moving frame reaches the end point. DRAWINGS

1 is a schematic view of a specific embodiment of a circuit breaker chassis according to the present invention; FIGS. 2a and 2b are schematic views of the motor assembly 1 of the circuit breaker chassis of FIG. 1; FIGS. 3a and 3b are FIG. 4 is a schematic view of the clutch body 2 of the circuit breaker chassis shown in FIG. 1; FIGS. 4a and 4b are schematic views of the suction cup 3 of the circuit breaker chassis of FIG.

5a and 5b are schematic views of the first sprocket 4 of the circuit breaker chassis of Fig. 1; Figs. 6a and 6b are schematic views of the second sprocket 6 of the circuit breaker chassis of Fig. 1; Figs. 7a and 7b are diagrams 1 is a schematic view showing the assembly of the motor assembly 1, the clutch body, the suction cup 3 and the first sprocket 4 in the circuit breaker chassis.

Throughout the specification and the drawings, the same reference numerals indicate the same or similar features. The reference numerals used herein are as follows:

1-motor assembly; 11-motor; 12-reducer; 13-output shaft; 2-clutch body; 3-suction Disk; 31-first boss; 4-first sprocket; 41-second boss; 5-drive chain; 6-second sprocket; 7- screw block; 8-screw; 9-moving frame detailed description

The illustrative aspects of the present invention are now described in detail with reference to the following description and drawings. The drawings of the application are not to be considered in all respects as the actual dimensions of the embodiments, and variations in the dimensions are not to be construed as limiting the invention.

In the following, "shown in FIG." or the like, refers to a specific technical feature with reference to a certain drawing, but it should not be understood that the specific technical feature or its equivalent is only included in the In the drawings.

In the following certain directional terms, such as "upper end" and other directional terms, are the directions in which the feature is or are pointed when facing the drawing. However, when the application changes, the direction of these directional terms will change accordingly.

1 shows a particular circuit breaker electric chassis truck in accordance with the present invention. The apparatus includes a static frame and a carriage 9 that is movable relative to the stationary frame. Among them, the static frame is fixedly installed to keep the switch from moving according to specific requirements. A screw rod 8 is mounted on the static frame, and the screw rod 8 is fixed with a screw block 7 fixed to the moving frame 9. A motor assembly 1 is mounted on the motor frame, and the movement of the motor assembly 1 is transmitted to the screw rod 8 through a sprocket transmission mechanism to drive the screw rod block 7, the moving frame 9 and the motor assembly and the chain transmission mechanism. An electromagnetic clutch is mounted between the motor assembly 1 and the sprocket transmission mechanism along the axial movement of the screw shaft 8.

The individual components or components of the chassis will be described in detail below. It is to be understood that all the descriptions of the present invention are intended to be illustrative only, and those skilled in the art will not be able to recite all possible variations, modifications, or equivalents. Of course, it is included in the disclosure and scope of the present invention.

The circuit breaker electric chassis car referred to herein is a device for electrically moving the circuit breaker position as needed. In the embodiment shown in Figure 1, the apparatus includes a fixed static frame that can be held stationary in the switch rejection by any means known in the art, and the static frame is supported on the static frame. Shelf 9. Wherein, the screw frame 8 is supported on the static frame, and at the same time, the moving frame 9 is fixedly mounted with the screw block 7 matched with the screw rod 8. The screw rod 8 can be rotated by the transmission device, so that the threaded rod block 7 of the screw rod 8 is axially moved along the screw rod 8, and further The moving frame 9 and the circuit breaker are moved axially along the screw 8, for example, between the experimental position and the working position.

The motor assembly 1 in this embodiment may be various suitable motors, preferably a DC forward-reverse energy storage motor 11, which can be rotated forward and reverse under control. As an assembly component, the motor assembly 1 can also include a speed reducer 12, as shown in Fig. 2, so that the rotational speed of the output shaft 13 of the motor assembly 1 meets the specified requirements. The output shaft 13 of the motor assembly 1 can be in various suitable shafting forms. For example, as shown in the figure, the output shaft 13 of the motor assembly 1 is a stepped shaft, wherein the inner diameter portion of the clutch body 2 is mounted. The first sprocket 4 and the suction cup 3 are mounted on the outer small diameter portion.

The rotation of the screw 8 described above is achieved by a transmission. In the embodiment shown in Fig. 1, the transmission is a chain drive mechanism. Of course, the transmission can also be other transmission mechanisms, such as a 雉 gear transmission mechanism, a belt transmission mechanism, and the like. The chain transmission mechanism includes a first sprocket 4 (shown in FIG. 5) supported on the output shaft 13 of the motor assembly 1 through a bearing, and a second sprocket 6 fixedly mounted on the lead screw 8 (as shown in FIG. 6). And a drive chain 5 that cooperates with the first sprocket 4 and the second sprocket 6. The first sprocket 4 can be supported on the motor assembly 1 output shaft 13 by various suitable means, such as angular contact ball bearings, deep groove ball bearings, needle bearings, plain bearings, and the like. The first sprocket 4 is rotatable relative to the motor assembly 1 output shaft 13 and the first sprocket 4 is not movable in the axial direction. The second sprocket 6 is movably mounted on the lead screw 8 along the axial direction of the lead screw 8, so that the lead screw 8 can be rotated by the second sprocket 6. The second sprocket 6 is located between the lead screw block 7 and a cross member of the carriage 9. In order to move the second sprocket 6 in the axial direction of the screw rod 8, a groove is provided on the surface of the screw rod 8 along the axial direction of the screw rod 8, and at the same time, the side wall of the shaft hole of the second sprocket 6 is provided with The groove is adapted to the boss. The second sprocket 6 is fitted over the lead screw 8, and the boss is embedded in the groove on the surface of the screw 8. When the second sprocket 6 is rotated by the drive chain 5, the second sprocket 6 drives the screw 8 through the boss on the shaft hole thereof, so that the screw block 7 mounted on the screw 8 will follow the wire. The axial movement of the rod 8 further drives the carriage 9 and the motor assembly 1 connected to the screw block 7 to move together. Meanwhile, since the second sprocket 6 is mounted to a beam of the carriage 9 and the screw block 7 assembly, the second sprocket 6 will also be along the axial direction of the screw 8 with the motor assembly 1 and the first sprocket 4 Moves synchronously with components such as the drive chain 5. Corresponding two bosses are disposed on the inner shaft hole of the second sprocket shown in FIGS. 6a and 6b, and correspondingly, the surface of the screw rod is provided with two grooves adapted thereto, thereby making the first The torque transmission of the two sprocket to the screw is more balanced, which makes the rotation of the screw more stable, reduces the stress on the screw and prolongs the life of the screw.

The electromagnetic clutch includes an electromagnetic clutch clutch body (shown in FIG. 3) and a suction cup 3 (shown in FIG. 4), and the clutch body is fixedly mounted on the output shaft 13 of the motor assembly 1. Correct Therefore, it is conceivable by those skilled in the art that the clutch body can be integrally fixed on the output shaft, so that the housing of the clutch body can be fixed to the housing of the motor assembly only when the output shaft rotates integrally. The rotatable portion within the housing rotates with the output shaft, such as a friction disk, thereby reducing the load on the output shaft. The suction cup 3 is supported on the output shaft 13 of the motor assembly 1 and is movable along the axial direction of the output shaft 13 of the motor assembly 1 under the magnetic force of the clutch body and rotates around the axis of the motor assembly 1, wherein, the suction cup 3 The chuck 3 is always engaged with the first sprocket 4 in a torque transferable manner during rotation along the axis of the output shaft 13 of the motor assembly 1. In the specific implementation, the suction cup 3 and the first sprocket 4 are respectively provided with a first boss and a second boss which are matched and resisted on opposite sides, and the first boss will push when the suction cup 3 rotates. The second boss thus rotates the first sprocket 4, the length of the output shaft 13 of the first boss and the second boss along the motor assembly 1 is greater than the relative friction surface of the chuck 3 and the clutch body along the motor assembly 1 The distance of the output shaft 13. The first and second bosses can be of various suitable shapes and configurations. In the embodiment, the first boss and the second boss are annular bosses provided along the periphery of the suction hole 3 and the shaft hole of the first sprocket 4, respectively. The structure provided along the periphery of the suction hole 3 and the shaft hole of the first sprocket 4 has the advantage of increasing the support of the motor assembly 1 output shaft 13 to the suction cup 3 and the first sprocket 4, and at the same time effectively reducing the suction cup 3 and the The overall volume of a sprocket 4 is thus more conveniently arranged.

The electromagnetic clutch of this embodiment can be various types of electromagnetic clutches in the art. The electromagnetic clutch generally includes a clutch body 2 having a magnetic force and a suction cup 3. The clutch body 2 and the suction cup 3 have opposite friction surfaces, and the suction cup 3 can be engaged with the friction surface of the clutch body 2 by the magnetic field of the clutch body 2 or separate. The electromagnetic clutch controls the engagement and disengagement of the clutch by the on and off of the internal coil. For the compact requirements of the present invention, the clutch must have a small volume while being designed with power to facilitate placement in a limited space. In the present invention, a dry single-plate electromagnetic clutch, a dry multi-plate electromagnetic clutch, a wet multi-plate electromagnetic clutch, a magnetic powder clutch, a slip electromagnetic clutch, or the like can be selected. The electromagnetic clutch can work in a combination of energization or power failure. The dry single-plate electromagnetic clutch generates a magnetic suction cup 3 when the coil is energized, and the clutch is in an engaged state; when the coil is powered off, the suction cup 3 is separated, and the clutch is in a separated state. The dry multi-plate wet multi-plate electromagnetic clutch principle is the same as the dry single-plate electromagnetic clutch. In addition, several friction pairs are added. The same volume torque is larger than the dry single-plate electromagnetic clutch. The wet multi-plate electromagnetic clutch must have oil when working. Or other coolant to cool. In the present embodiment, the electromagnetic clutch includes a clutch body 2 (Fig. 3) and a suction cup 3 (Fig. 4). The clutch body 2 is energized under the control of the undercarriage control system to generate a magnetic field, and the suction cup 3 is attracted to the clutch body 2 by a magnetic field. The opposite surface of the clutch body 2 and the suction cup 3 Do not have a friction surface. In the state of the suction, the clutch body 2 fixedly coupled to the output shaft 13 of the motor assembly 1 is rotated by the motor assembly 1, and the suction cup 3 is rotated by the friction, thereby transmitting the rotation to the first through the suction cup 3. A sprocket 4. When the clutch body 2 is powered off under the control of the undercarriage control system, there is no longer a magnetic field for absorbing, the suction cup 3 is separated from the clutch body 2, and the clutch body 2 is fixedly coupled to the output shaft 13 of the motor assembly 1. It will be idling under the driving of the motor assembly 1, and the rotation of the suction cup 3 will no longer rotate, so that the first sprocket 4 also stops rotating. In order to transmit the torque better, a friction enhancing structure is provided on the opposite friction surface of the suction cup 3 and the clutch body. Any suitable friction-enhancing structure in the art may be selected, such as coating a coating having a more excellent friction effect on the friction surfaces of the clutch body 2 and the suction cup 3, and further on the friction surfaces of the clutch body 2 and the suction cup 3. Structures such as bumps or ridges to increase friction.

The electric chassis truck of the present invention further includes a control system, the starting and stopping of the motor assembly 1 and the clutching of the electromagnetic clutch, and the actions of the various components or mechanisms of the electric chassis vehicle are controlled by the control system, thereby realizing The purpose of unattended or remote control of the power station is to meet the needs of the smart grid. The control system includes a moving end position switch of the moving frame 9, and the moving end position switch is a normally closed switch. When the moving frame 9 reaches the end point, the normally closed switch transmits a signal to the control system to stop the motor assembly 1 from operating.

The electric chassis of the present invention can be applied to circuit breakers of different voltage levels, such as 12kV circuit breakers, especially for 40.5KV circuit breakers. Since the higher the voltage, the higher the insulation requirement, the larger the volume and weight of the circuit breaker, and the greater the load carrying capacity required for the chassis. In the prior art, electric chassis vehicles are equipped with mechanical clutches. The disadvantage of an electric chassis mounted with a mechanical clutch is that the electric chassis is large in size and insufficient in reliability. In addition, the size of the electric chassis and its clutch cannot be designed too large due to the limited volume of the switch. At the same time, the higher the voltage, the higher the insulation requirements of the switch, and the larger the volume and weight of the circuit breaker. This creates a contradiction between the load capacity of the chassis and the volume limit. For a 40.5KV circuit breaker, if a small mechanical clutch is used, it will not be able to transmit enough torque to drive the circuit breaker. If a large mechanical clutch is used, it will be limited by the space in the switch and cannot be installed effectively. The chassis of the present invention successfully uses an electromagnetic clutch as a clutch for power transmission. Due to the small size and simple structure of the electromagnetic clutch, the required space can be significantly reduced, and the contradiction between the bearing capacity and the space limitation of the chassis can be completely solved, thereby realizing the electrification and automatic control of the circuit breaker of the voltage level of 40.5 kV.

The operation of the circuit breaker chassis of the present invention will be briefly described below.

When the chassis of the present invention needs to be operated, the motor 11 is energized by the control system, the motor 11 is rotated and adjusted to a lower operating speed by the reduction gear unit therein to output from the motor assembly 1 output shaft 13. The output shaft 13 of the motor assembly 1 drives the electromagnetic clutch to rotate. Under the control of the control system, the electromagnetic clutch generates a magnetic field, and the suction cup 3 is sucked by the electromagnetic clutch under the action of the magnetic field, and the electromagnetic clutch rotates under the frictional force of the opposite friction surfaces of the two. Since the suction cup 3 and the opposite surface of the first sprocket 4 have bosses that are engaged with each other, the suction cup 3 drives the first sprocket 4 to rotate and drives the second sprocket 6 to rotate through the transmission chain 5. The second sprocket 6 rotates through the boss of the intermediate shaft hole to drive the screw 8 to rotate, and the screw block 7 fitted to the screw 8 moves along the axial direction of the screw 8. Since the motor assembly 1 and the screw block 7 are fixedly mounted on the moving frame 9, the motor assembly 1 and the moving frame 9 also move along with the axial direction of the screw 8 under the action of the screw block 7, and at the same time, The two sprocket wheels 6 are interposed between the threaded rod block 7 and a cross beam of the moving frame 9, and the second sprocket 6 is also under the action of the screw block block and the moving frame 9 and on the shaft on the surface of the screw rod 8. Under the guidance of the groove, the axial direction of the screw rod 8 moves synchronously with the components such as the screw block block and the moving frame 9 and the motor assembly 1.

While the present invention has been described in terms of a plurality of embodiments and at the same time many details of the chassis of the present invention are described, the above details are not to be construed as limiting the scope of the present invention to the details . Other advantages and modifications of the present invention will become apparent to those skilled in the art after reading this disclosure. Therefore, changes may be made without departing from the spirit and scope of the invention as claimed.

Claims

Claim

A circuit breaker electric chassis vehicle comprising a static frame and a moving frame (9) movable relative to the static frame, wherein the static frame (9) is provided with a screw (8), the screw ( 8) equipped with a screw block (7) fixed to the moving frame (9), and the motor frame (9) is further equipped with a motor assembly (1), the motor assembly (1) Rotation is transmitted to the screw (8) through the transmission mechanism to drive the screw block (7), the moving frame (9) and the motor assembly (1) to move along the axial direction of the screw (8), characterized in that An electromagnetic clutch is mounted between the motor assembly (1) and the transmission mechanism.

2. The electric chassis according to claim 1, wherein the transmission mechanism is a chain transmission mechanism, and is rotatably mounted on the output shaft (13) of the motor assembly (1) about the output shaft (13) a first sprocket (4) and a second sprocket (6) axially movably mounted on the lead screw (8) along the lead screw (8) and with the first sprocket (4) and the second The sprocket (6) cooperates with the transmission chain (5). When working, the first sprocket (4) rotates around the output shaft (13) under the driving of the electromagnetic clutch and drives the second sprocket through the transmission chain (5) ( 6) Rotate with the screw (8), while the second sprocket will move axially along the screw (8).

3. The electric chassis according to claim 2, wherein the electromagnetic clutch comprises a clutch body (2) and a suction cup (3), and the clutch body (2) and the suction cup (3) are respectively provided with relative Friction surface, the suction cup (3) is supported on the output shaft (13) of the motor assembly (1) and can be output along the motor assembly (1) under the magnetic force of the clutch body (2) Axial movement, wherein the suction cup (3) is always in a torque transferable manner with the first sprocket (4) during axial movement of the suction cup (3) along the output shaft (13) of the motor assembly (1) Engage.

The electric chassis truck according to claim 3, wherein the suction cup (3) and the first sprocket (4) are respectively provided with opposite first projections (31) on the opposite surfaces thereof. And a second boss (41), the first boss (31) will engage and push the second boss (41) to rotate the first sprocket (4) when the chuck (3) is rotated, the first boss (31) and the second boss (41) joint surface along the motor assembly (1) output shaft (13) has a length greater than the suction disc (3) and the clutch body relative friction surface along the motor assembly (1) output shaft ( 13) the distance.

The electric chassis according to claim 4, wherein the first boss (31) and the second boss (41) are respectively along the axis of the suction cup (3) and the first sprocket (4) The perimeter of the hole is set.

6. The electric chassis according to claim 4, wherein the suction cup (3) and the clutch body are provided with a friction reinforcing structure on a surface of the friction surface.

7. An electric chassis according to claim 1, characterized in that the motor assembly (1) comprises a shifting device (12).

8. An electric chassis according to any of the preceding claims, further comprising a control system, the start and stop of the motor assembly (1) and the clutching of the electromagnetic clutch are both controlled by the control system.

9. The electric chassis according to claim 8, wherein the control system comprises a moving end position switch of the moving frame (9), the moving end position switch is a normally closed switch, and when the moving frame (9) arrives At the end point, the normally closed switch sends a signal to the control system to stop the motor assembly (1) from operating.

10. The electric chassis according to claim 1, wherein the circuit breaker is a 40.5 KV circuit breaker.