Operating mechanism suitable for vacuum circuit breaker

Abstract

The utility model relates to an operating mechanism suitable for a vacuum circuit breaker, which is provided with an operating mechanism and a buffer oil cylinder, a non-driving side of a driving shaft of the operating mechanism extends out of the operating mechanism and is used as a piston rod of the buffer oil cylinder, and a piston of the buffer oil cylinder is fixedly arranged on the driving shaft in a cylinder body of the buffer oil cylinder. The inner wall of a cylinder body of the buffering oil cylinder is provided with one or more overflowing groove operation mechanisms extending in the axial direction, one-way channels are arranged between overflowing grooves and cavities on the two sides, the operation mechanisms are permanent magnet operation mechanisms, permanent magnets of the operation mechanisms are annular permanent magnets magnetized in the radial direction and are provided with magnet yoke assemblies, the number of magnet exciting coils of a movable iron core is two, and the number of the magnet exciting coils of the movable iron core is two. The two magnets are located on the two axial sides of the permanent magnet. According to the utility model, the internal magnetic field distribution is reasonable, an opening spring is not needed, opening and closing bounce can be effectively avoided, a good opening and closing speed is maintained, and the operation requirements of a circuit breaker and the like are better met.

Description

Technical Field

[0001] The utility model relates to an electromagnetic permanent magnet composite operating mechanism, which can be mainly used for the opening and closing (opening and closing) operations of vacuum circuit breakers and other suitable devices. Background Art

[0002] The existing circuit breaker operating mechanisms can be mainly divided into several types: manual operating mechanism, electromagnetic operating mechanism, permanent magnetic operating mechanism, spring operating mechanism and motor operating mechanism. Among them, the permanent magnetic operating mechanism has the characteristics of simple structure, high reliability, fast response speed and low power consumption, and is widely used in power, coal mining, steel, petroleum, chemical industry, shipbuilding, railway and other systems. Most of the existing permanent magnetic operating mechanisms are monostable mechanisms. Due to the setting of the opening spring, this type of permanent magnetic operating mechanism is difficult to take into account the technical requirements of high-speed opening and closing and reliable stability, and there are problems such as spring fatigue. Therefore, the bistable permanent magnetic operating mechanism is developed. For example, Chinese patent document CN211929419U discloses an operating mechanism composed of an electromagnetic and permanent magnet composite, including a housing and a guide rod, an upper end cover is fixed on the upper end of the housing, and a lower end cover is fixed on the lower end, the upper end cover, the housing and the lower end cover form a cavity, a magnetic coil is arranged in the cavity, a permanent magnet is arranged above the magnetic coil, and the permanent magnets arranged above the magnetic coil are all circular rings, and an electromagnetic moving iron is arranged in the magnetic coil and the permanent magnet, and the guide rod passes through the upper end cover, the electromagnetic moving iron and the lower end cover in sequence, and the guide rod and the electromagnetic moving iron are fixedly connected. The operating mechanism has a simple structure, convenient operation and maintenance, will not produce malfunction of the circuit breaker, the opening and closing action is clean and neat, the contact pressure and holding force are stable, the opening speed is fast, and the holding force is stable. However, due to the fact that the electromagnetic moving iron is closer to the end point during the opening or closing process, the greater the suction force is, the acceleration and speed are significantly increased, and it is easy to appear the phenomenon of opening and closing bounce or even opening and closing failure. In addition, the operating mechanism also has room for further improvement in structure. Utility Model Content

[0003] The utility model aims to reduce or avoid the circuit breaker opening and closing bounce phenomenon and better meet the operation requirements of the circuit breaker and the like.

[0004] The technical solution of the utility model is: adapted to the operating mechanism of a vacuum circuit breaker, provided with an operating mechanism (or operating mechanism body) and a buffer oil cylinder, the operating mechanism is provided with a drive shaft, the non-driving side (or non-driving end, or buffer connection end) of the drive shaft extends from the operating mechanism and serves as a piston rod of the buffer oil cylinder, and the piston of the buffer oil cylinder is fixedly mounted on the drive shaft located in the cylinder body of the buffer oil cylinder.

[0005] Furthermore, the buffer cylinder is coaxial with the operating mechanism (the axes are on the same straight line), the piston divides the cavity of the cylinder into a first cavity and a second cavity, and one or more axially extending flow grooves are provided on the inner wall of the cylinder body. The length of the flow groove (axial span or axial dimension) is adapted to the stroke of the piston (actual working stroke), and can usually be slightly shorter than or equal to the stroke of the piston. When the piston is located in the middle of the stroke range, or in the main stroke range of the piston (most of the area in the stroke range), the two ends of the flow groove are respectively located in the first cavity and the second cavity. When the piston is close to and / or located at the end of the stroke on either side, the circumferential surface (side) of the piston blocks the corresponding side end points of the flow groove or passes over the corresponding side end points of the flow groove (the two ends of the flow groove are located in the same cavity).

[0006] The flow groove may be in the shape of an axially extending column (a shape with equal cross sections at all locations), and its cross section may be in any suitable shape, such as a fan shape, a rectangle, a semicircle, a semi-ellipse, etc.

[0007] Furthermore, the first cavity and the second cavity are preferably respectively provided with one-way channels respectively connected to the flow groove, and the one-way channels are provided with one-way valves that limit flow from the flow groove to the corresponding cavity (the first cavity or the second cavity).

[0008] Furthermore, a sliding seal (a seal that allows the driving shaft to slide relative to the buffer cylinder cover) is provided between the driving shaft and the buffer cylinder cover through which the driving shaft passes.

[0009] Typically, the buffer cylinder and the operating mechanism can be fixedly connected as one body.

[0010] Preferably, the operating mechanism is a permanent magnet operating mechanism (including an electromagnetic and permanent magnet combined operating mechanism).

[0011] For example, the permanent magnet operating mechanism may be provided with a permanent magnet, a moving iron core and a yoke assembly, wherein the yoke assembly includes a cylinder and a first end cover and a second end cover respectively covering both ends of the cylinder, the cylinder, the first end cover and the second end cover of the yoke assembly are all made of yoke material, the permanent magnet is a radially magnetized annular permanent magnet, the outer peripheral surface (outer surface) of which is in contact with the inner wall (inner surface) of the cylinder, and is axially located in the middle of the cylinder, the moving iron core is located in the cylinder, the driving shaft passes through the moving iron core, the first end cover and the second end cover along the axis, is fixedly connected to the moving iron core, and is slidably connected to the first end cover and the second end cover (connected in a movable connection manner that allows the two to slide relative to each other), the excitation coil (or magnetic coil) of the moving iron core includes a first coil and a second coil, both of which are ring (cylinder) shaped, wherein the first coil is fixed between the permanent magnet and the first end cover, and the second coil is fixed between the permanent magnet and the second end cover.

[0012] Preferably, the first coil and the second coil are the same coil.

[0013] Preferably, the length of the moving iron core is greater than the length of the permanent magnet.

[0014] Preferably, the inner end surfaces of the first end cover and the second end cover may be provided with an axially protruding convex plane (the end surface is a flat convex structure).

[0015] In the axial direction, an end surface of the convex plane is located between two ends of adjacent excitation coils.

[0016] A magnetic isolation sleeve is fixedly arranged on the central through hole (the central through hole for passing the drive shaft) of the first end cover and / or the second end cover.

[0017] The inner wall (inner surface) of the magnetic isolation sleeve may be provided with a wear-resistant layer with low friction (for example, low dynamic and static friction coefficient).

[0018] If necessary, the permanent magnets can be held in an embedded state in the middle of the end surfaces of both ends of the moving iron core (the annular area adjacent to the drive shaft).

[0019] The state-maintaining permanent magnet may be a small annular permanent magnet, the polarity of its outer end surface (the end surface facing the adjacent end cover) being opposite to the polarity of the opposite surface (inner end surface) of the corresponding (adjacent) end cover.

[0020] The beneficial effects of the utility model are as follows: due to the provision of a buffer oil cylinder, a damping (reverse) force is applied to the piston when approaching the end point of the opening and closing switch, thereby reducing the impact energy at the end point and alleviating or avoiding the opening and closing switch bouncing phenomenon; due to the provision of an axial flow groove on the inner wall of the cylinder body of the buffer oil cylinder, the extension range of the flow groove corresponds to the main stroke of the piston (the stroke area not approaching the end point, or in other words, the entire stroke area except the end point area), in the main stroke of the piston, the working area on one side (forward direction) of the piston in the buffer oil cylinder The medium (for example, oil) can flow smoothly to the other side of the piston through the flow groove, and will not produce a damping effect that substantially hinders the movement of the piston / drive shaft. Through the reasonable design of the dimensions of each part, the damping action distance / damping action time can be controlled to be very small while effectively avoiding the opening and closing bounce, so it will not have a substantial impact on the opening and closing speed of the circuit breaker; because there are one-way channels connected to the flow grooves at both ends of the oil cylinder cavity, when the moving iron core starts to open or close, the piston on one side (forward direction) The working medium can flow smoothly to the other side of the piston through the one-way channel, thereby avoiding the damping effect at the start of the action and avoiding unnecessary negative impact on the opening and closing speed; since the first coil and the second coil are provided, an excitation current can be applied to one of the coils or the two coils can be excited simultaneously according to actual needs, so as to meet different requirements for the opening and closing speeds; since the force direction of the moving iron core after the coil is energized is determined by the current direction of the coil, the closing and opening actions of the moving iron core can be achieved by changing the injection direction of the excitation current, and there is no need to set an opening spring; since in the closing state and the opening state, the moving iron core is attracted to the end cover on the corresponding side respectively, and the opening and closing states are kept unchanged by the magnetic field generated by the permanent magnet, so as to achieve a bistable state; since the buffer cylinder can absorb external force interference to a certain extent, it is beneficial to improve the reliability of the opening and closing holding; since the state-holding permanent magnet can be set or not according to actual needs, the holding force of the opening and closing can be further enhanced by the attraction of the state-holding permanent magnet and the end cover when necessary, so as to meet the holding force requirements in corresponding harsh occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of an implementation method of the utility model;

[0022] Figure 2 The utility model is a schematic cross-sectional view of a buffer oil cylinder body with a flow groove. DETAILED DESCRIPTION

[0023] See also Figure 1 and Figure 2The utility model provides a buffer oil cylinder on the basis of the operating mechanism (or the operating mechanism body), the buffer oil cylinder is coaxial with the operating mechanism body (the axis is on the same straight line), the non-driving end (the end not connected to the circuit breaker) of the driving shaft 10 of the operating mechanism extends into the buffer oil cylinder or passes through the buffer oil cylinder, and serves as the piston rod of the buffer oil cylinder. The piston 52 of the buffer oil cylinder is fixedly connected to the driving shaft located in the cylinder body 51, and can move axially with the driving shaft. The piston divides the cavity of the oil cylinder into two cavities, which can be respectively called the first cavity and the second cavity. For example, the cavity near the operating mechanism is called the first cavity, and the other cavity is called the second cavity. A plurality of (one or more) axially (or vertically, corresponding to the vertical direction in the upright state) extending flow grooves 54 are provided on the inner wall of the cylinder body. The axial span (length) of the flow grooves is adapted to the actual stroke of the piston. Within the main stroke range of the piston, a portion of the flow grooves (the opening of the flow grooves) is located in the first cavity, and another portion is located in the second cavity. This allows the working medium (e.g., pressure oil) of the buffer cylinder to flow smoothly from one cavity to another through the flow grooves, thereby avoiding obstruction to the movement of the piston / drive shaft. When the drive shaft / piston moves to a point close to the corresponding direction, the circumference (side) of the piston moves to the end of the corresponding side of the flow groove (the piston's forward direction), so that the working medium in the cavity in the piston's forward direction cannot directly enter the flow groove. The working medium in the cavity is squeezed by the piston movement, exerting a reverse force on the piston, thereby hindering the piston movement. There is a small annular gap (ring gap) between the piston circumference and the inner wall of the cylinder body. The annular gap constitutes a throttling channel for the medium. The working medium can flow through the annular gap, and throttling and buffering are achieved through the annular gap resistance. The damping size can be controlled by setting an appropriate annular gap width to meet the buffering needs. All relevant dimensions and mutual matching ratios can be determined through experiments or appropriate simulation operations. The buffering effect reduces the piston acceleration or turns it into a negative value, thereby reducing the collision or impact force when reaching the end position and avoiding the drive shaft from jumping.

[0024] The flow groove can be connected to the cavities on both sides of the cylinder body (the first cavity and the second cavity) through the corresponding one-way channel 56. The one-way channel can be arranged in the wall of the cylinder body, and the openings at both ends (the inlet 59 and the outlet 58) are respectively located in the corresponding flow groove and the corresponding cavity (the unchanged area in the cavity). A one-way valve 57 that only allows the working medium to flow from the flow groove into the corresponding cavity is arranged in the one-way channel. Therefore, when the piston starts to move (when the opening or closing action starts), the working medium can flow from the cavity in the forward direction of the piston into the other cavity through the flow groove and the one-way channel, thereby avoiding obstruction to the movement of the piston / drive shaft at the beginning of opening and closing (the starting stage), and avoiding unnecessary influence on the opening and closing speed.

[0025] The cylinder body of the buffer cylinder can be fixedly connected to the base of the operating mechanism (main body) (for example, bolts are fastened to the corresponding shell end face / base of the operating mechanism), and a seal is provided between the drive shaft and the buffer cylinder cover (end cover of the buffer cylinder) through which it passes. This seal can be achieved by adopting the existing sealing technology between the cylinder piston rod and the cylinder body (cylinder cover), and the other structures of the one-way valve and the buffer cylinder can also adopt the existing cylinder-related technology.

[0026] The operating mechanism (main body) can adopt any suitable permanent magnet operating mechanism (including an operating mechanism of a combination of electromagnetic and permanent magnet).

[0027] As a preferred embodiment (see Figure 1 ), the operating mechanism is provided with a permanent magnet 21, a moving iron core 31 and a yoke assembly. The yoke assembly includes a cylinder 24 and a first end cover 22 and a second end cover 23 respectively covering the two ends of the cylinder. The cylinder and the first end cover and the second end cover of the yoke assembly are made of a high-permeability soft magnetic material (which can be called a yoke material) suitable for being used as a yoke. The permanent magnet is a radially magnetized annular permanent magnet, which can be an integral ring structure, or can be spliced ​​and fixed into an annular shape by multiple parts (multiple pieces). The outer peripheral surface (outer side surface) of the permanent magnet fits the inner wall of the cylinder (corresponding part), and is axially located (corresponding to) the middle part of the cylinder. The drive shaft is fixedly penetrated on the moving iron core along the axis of the moving iron core, and the two ends respectively pass through the central through holes of the first end cover and the second end cover, and are connected to the first end cover and the second end cover in an axially movable (for example, sliding) manner. The drive shaft passing through the first end cover is used to connect (operate) the circuit breaker, and the drive shaft passing through the second end cover extends into (or passes through) the buffer cylinder, and is used as the piston rod of the buffer cylinder.

[0028] The length (axial dimension) of the moving iron core is preferably greater than the length of the permanent magnet. For example, it can be equal to or similar to the sum of the length of the permanent magnet and the length of a single coil. The coil length can be roughly similar to the length of the permanent magnet to facilitate the optimization of the magnetic lines of force inside the yoke assembly (the internal magnetic field generated by the permanent magnet).

[0029] The moving iron core usually has two excitation coils, including a first coil 34 and a second coil 35. Both coils are ring (cylindrical) shaped and can usually adopt the same structure, wherein the first coil is fixed between the permanent magnet and the first end cover, and the second coil is fixed between the permanent magnet and the second end cover. When any coil is energized or both coils are energized in the same direction (the direction that makes the moving iron core magnetized in the same direction), the moving iron core is magnetized and interacts with the magnetic field generated by the permanent magnet, thereby implementing the opening action or closing action. In the opening or closing state, the moving iron core is attracted to the corresponding end cover (the first end cover or the second end cover). The current direction of the coil can be selected according to the magnetic polarity of the attraction surface of the corresponding end cover, so that the polarity of the attraction surface of the moving iron core is the same as the polarity of the attraction surface of the corresponding end cover. The moving iron core moves toward the other end cover under the action of the magnetic force until it is attracted with the other end cover. After attraction, the coil current is disconnected. Under the action of the magnetic field generated by the permanent magnet, the moving iron core and the corresponding end cover continue to maintain the attraction state, thereby achieving stable maintenance of the open or closed state.

[0030] According to the requirements for the opening and closing speed of the circuit breaker, one coil can be energized or both coils can be energized in the same direction at the same time. The material properties of the moving iron core can be appropriately selected so that the moving iron core can work effectively when one coil is energized and when both coils are energized at the same time.

[0031] The inner end surface of each end cover may be provided with an axially protruding convex plane 26 to gather magnetic lines of force and optimize the internal magnetic field.

[0032] A magnetic isolation sleeve (not shown) can be fixedly installed on the through hole in the center of the end cover for passing the drive shaft. A wear-resistant layer (for example, a ceramic wear-resistant layer, or a wear-resistant coating) can be provided on the inner wall of the magnetic isolation sleeve, and the wear-resistant layer has low friction to facilitate the axial movement of the drive shaft.

[0033] Respective protective layers can be provided on the outer sides of the cylinder, the first end cover and the second end cover respectively. For example, the cylinder, the first end cover and the second end cover can be fixedly mounted on their respective protective layers respectively. After assembly, these protective layers can constitute the shell of the operating mechanism.

[0034] If necessary, small state-maintaining permanent magnets can be embedded in the middle of the end faces of both ends of the moving iron core (the annular area near the drive shaft), including the first state-maintaining permanent magnet 41 near the first end cover and the second state-maintaining permanent magnet 2 near the second end cover. The polarity of the outer end face of the state-maintaining permanent magnet is opposite to the polarity of the opposite face (inner end face) of the corresponding end cover, so as to improve the holding force of the moving iron core and the corresponding end cover in the attracted state. In a relatively harsh environment, this setting helps to improve the reliability of the opening and closing state maintenance.

[0035] The magnetic force of the state-maintaining permanent magnet can be set according to actual needs, and when the state-maintaining reliability is required in the corresponding usage scenario, it is avoided that the excitation current is unnecessarily increased due to excessive magnetic force.

[0036] Unless otherwise specified or when one preferred or optional technical means is a further limitation of another technical means, the preferred and optional technical means disclosed in the present utility model can be arbitrarily combined to form several different specific implementation methods.

Claims

1. An operating mechanism adapted for a vacuum circuit breaker is provided, wherein the operating mechanism is provided with a drive shaft, characterized in that A buffer oil cylinder is also provided, the non-driving side of the drive shaft extends from the operating mechanism and serves as a piston rod of the buffer oil cylinder, and the piston of the buffer oil cylinder is fixedly mounted on the drive shaft located in the cylinder body of the buffer oil cylinder.

2. The operating mechanism adapted for a vacuum circuit breaker according to claim 1, characterized in that The buffer cylinder is coaxial with the operating mechanism, and the piston divides the cavity of the cylinder into a first cavity and a second cavity. One or more axially extending flow grooves are provided on the inner wall of the cylinder body. The length of the flow groove is adapted to the stroke of the piston. Within the main stroke range of the piston, the two ends of the flow groove are respectively located in the first cavity and the second cavity. When the piston is close to and / or located at the end of the stroke on either side, the circumferential surface of the piston blocks the corresponding side end point of the flow groove or passes over the corresponding side end point of the flow groove.

3. The operating mechanism adapted for a vacuum circuit breaker according to claim 2, characterized in that The first cavity and the second cavity are respectively provided with one-way channels respectively connected with the flow grooves, and the one-way channels are provided with one-way valves that limit the flow from the flow grooves to the corresponding cavity.

4. The operating mechanism adapted for a vacuum circuit breaker according to claim 1, characterized in that A sliding seal is arranged between the driving shaft and the buffer oil cylinder cover through which the driving shaft passes.

5. The operating mechanism adapted for a vacuum circuit breaker according to claim 1, characterized in that The buffer oil cylinder and the operating mechanism are fixedly connected as one body.

6. The operating mechanism for a vacuum circuit breaker according to any one of claims 1 to 5, characterized in that The operating mechanism is a permanent magnet operating mechanism.

7. The operating mechanism adapted for a vacuum circuit breaker according to claim 6, characterized in that The permanent magnet operating mechanism is provided with a permanent magnet, a moving iron core and a yoke assembly. The yoke assembly includes a cylinder and a first end cover and a second end cover respectively covering the two ends of the cylinder. The cylinder, the first end cover and the second end cover of the yoke assembly are all made of yoke material. The permanent magnet is a radially magnetized annular permanent magnet, whose outer peripheral surface is in contact with the inner wall of the cylinder and is axially located in the middle of the cylinder. The moving iron core is located in the cylinder, and the driving shaft passes through the moving iron core, the first end cover and the second end cover along the axis, is fixedly connected to the moving iron core, and is slidably connected to the first end cover and the second end cover. The excitation coil of the moving iron core includes a first coil and a second coil, and the first coil and the second coil are both annular, wherein the first coil is fixed between the permanent magnet and the first end cover, and the second coil is fixed between the permanent magnet and the second end cover.

8. The operating mechanism adapted for a vacuum circuit breaker according to claim 7, characterized in that The length of the moving iron core is greater than the length of the permanent magnet.

9. The operating mechanism adapted for a vacuum circuit breaker according to claim 7, characterized in that The inner end surfaces of the first end cover and the second end cover are both provided with axially protruding convex planes.

10. The operating mechanism adapted for a vacuum circuit breaker according to claim 7, characterized in that A magnetic isolation sleeve is fixedly arranged on the central through hole of the first end cover and / or the second end cover.

Images