Permanent magnet operating mechanism of vacuum circuit breaker

Abstract

A permanent magnet operating mechanism of a vacuum circuit breaker comprises a substrate, an annular magnet yoke and a static iron core are fixed below the substrate, and the static iron core is coaxially arranged in an inner cavity of the annular magnet yoke; the static iron core is of an annular structure with the upper end closed and the lower end open, a through hole is formed in the center of the upper end of the static iron core, an opening coil and a permanent magnet are arranged between the static iron core and the annular magnet yoke, and the opening coil is located above the permanent magnet. A coil rack is arranged in an inner cavity of the static iron core, and a closing coil is wound on the coil rack; a movable iron core is arranged below the static iron core and the annular magnet yoke, the movable iron core is of an inverted T-shaped structure, and the vertical end of the movable iron core is of a cylindrical structure and is inserted into a through hole in the center of the coil rack; an opening spring is installed in the cylinder structure, the lower end of the driving shaft penetrates through the opening spring and then is fixedly connected with the movable iron core, the upper end of the driving shaft penetrates through the through hole and the substrate and then is connected with an insulating pull rod of the vacuum circuit breaker, and the two ends of the opening spring abut against the movable iron core and the substrate respectively; the defects in the prior art are overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit breakers, and in particular relates to a permanent magnetic operating mechanism for a vacuum circuit breaker. Background Art

[0002] Existing permanent magnet operating mechanisms often use a shared electromagnetic circuit and permanent magnet circuit. During the closing and opening process, the excitation current needs to overcome the magnetic resistance of the permanent magnet, the coil, and the air gap to close the circuit, resulting in longer closing and opening times and increased current. In addition, the closing and opening coils and permanent magnets of existing permanent magnet operating mechanisms are stacked in the axial direction, making it difficult to reduce the height of the operating mechanism, which in turn makes the circuit breaker larger and cannot be used in scenarios with smaller installation spaces. In addition, the repulsion mechanism added to existing permanent magnet operating mechanisms is not integrated into the operating mechanism, but is instead arranged above or below the operating mechanism, further increasing the height of the operating mechanism. Summary of the Invention

[0003] The present invention provides a permanent magnetic operating mechanism for a vacuum circuit breaker to overcome the deficiencies of the prior art.

[0004] The technical solution adopted by the present invention is: a permanent magnetic operating mechanism for a vacuum circuit breaker, comprising a base plate, an annular magnetic yoke and a static iron core fixed below the base plate, and the static iron core coaxially arranged in the inner cavity of the annular magnetic yoke; the static iron core has an annular structure with a closed upper end and an open lower end, and a through hole in the center of its upper end; a tripping coil and a permanent magnet are arranged between the static iron core and the annular magnetic yoke, with the tripping coil located above the permanent magnet; a coil frame is provided in the inner cavity of the static iron core, and a closing coil is wound on the coil frame;

[0005] A moving iron core is provided below the static iron core and the annular magnetic yoke. The moving iron core has an inverted T-shaped structure, and its vertical end is a cylindrical structure that is inserted into the through hole in the center of the coil frame. A trip spring is installed in the cylindrical structure. The lower end of the drive shaft passes through the trip spring and is fixedly connected to the moving iron core. The upper end of the drive shaft passes through the through hole and the base plate and is connected to the insulating pull rod of the vacuum circuit breaker. The two ends of the trip spring are respectively pressed against the moving iron core and the base plate.

[0006] When closing the circuit breaker, the magnetic field generated by the energization of the closing coil forms a closing magnetic circuit on the static iron core and the moving iron core, causing the moving iron core to overcome the resistance of the opening spring and attract the static iron core and drive the drive shaft upward to complete the closing. After the closing is completed and the power is cut off, the magnetic field generated by the permanent magnet forms a double holding magnetic circuit with the static iron, the moving iron core and the annular magnetic yoke to maintain the closed state; when opening the circuit breaker, the magnetic field generated by the reverse energization of the opening coil weakens the magnetic force of the permanent magnet so that it is less than the closing holding force of the circuit breaker. Under the joint action of the contact spring and the opening spring, the moving iron core drives the drive shaft downward to complete the opening.

[0007] The lower end surface of the coil frame is provided with an annular groove, and a repulsion coil is wound in the annular groove; a repulsion disk is provided on the moving iron core at a position opposite to the repulsion coil.

[0008] An annular recessed groove is provided on the moving iron core at a position relative to the repulsion coil, and the repulsion disk is annular and fixed in the annular recessed groove.

[0009] An annular shoulder is provided on the outer periphery of the open end of the static iron core. The permanent magnet is annular and is sleeved on the outer periphery of the static iron core, with its lower end seated on the annular shoulder.

[0010] A second annular recess is provided on the moving iron core at a position opposite to the permanent magnet.

[0011] The substrate is made of non-magnetic material.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The present invention does not involve the permanent magnet in the closing circuit during closing. During the closing process, the excitation current of the closing coil does not need to overcome the magnetic resistance of the permanent magnet. This shortens the closing time and does not increase the closing current. Furthermore, after closing, the permanent magnet forms a dual magnetic circuit for holding the switch, increasing holding force while maintaining the same size.

[0014] 2. The opening circuit of the present invention is independent of the closing circuit. During opening, the opening coil only needs to weaken the magnetic force of the permanent magnet. Only a very small current is required to achieve rapid opening. If it works together with the repulsion coil, it can achieve opening time of 1-3ms.

[0015] 3. The static iron core, closing coil, moving iron core, yoke, opening coil and permanent magnet of the present invention are radially assembled together, with a compact structure. In addition, the repulsion coil is integrated into the closing coil, and the repulsion disk is integrated into the moving iron core. The repulsion mechanism does not increase the height of the product, so that the height of the permanent magnetic operating mechanism is reduced to 70-80mm, thereby reducing the volume of the circuit breaker and meeting the use of scenarios with smaller installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the present invention in the open state;

[0017] Figure 2 This is a schematic diagram of the structure of the present invention in the closed state;

[0018] Figure 3 It is a schematic cross-sectional view of the static iron core structure of the present invention;

[0019] Figure 4 It is a schematic cross-sectional view of the structure of the moving iron core of the present invention;

[0020] Figure 5 It is a schematic cross-sectional view of the coil frame structure of the present invention. DETAILED DESCRIPTION

[0021] The following is combined with Figure 1-5 The present invention is described in detail with specific embodiments.

[0022] A permanent magnetic operating mechanism for a vacuum circuit breaker includes a base plate 6 made of a non-magnetic material, an annular magnetic yoke 1 and a static iron core 3 fixed below the base plate 6, and the static iron core 3 is coaxially arranged within the inner cavity of the annular magnetic yoke 1. The static iron core 3 has an annular structure with a closed upper end and an open lower end, and a through hole 3-1 is defined at the center of its upper end. A tripping coil 7 and a permanent magnet 2 are disposed between the static iron core 3 and the annular magnetic yoke 1, with the tripping coil 7 located above the permanent magnet 2. A coil bobbin 8 is disposed within the inner cavity of the static iron core 3, and a closing coil 9 is wound around the coil bobbin 8.

[0023] A moving iron core 4 is provided below the static iron core 3 and the annular magnetic yoke 1. The outer periphery of the moving iron core 4 must extend beyond the permanent magnet 2 to below the annular magnetic yoke 1 to ensure the subsequent formation of a dual-retaining magnetic circuit. The moving iron core 4 has an inverted T-shaped structure, and its vertical end forms a cylindrical structure 4-1, which is inserted into the through-hole 8-1 in the center of the coil bobbin 8. A trip spring 12 is installed in the cylindrical structure 4-1. The lower end of the drive shaft 5 passes through the trip spring 12 and is fixedly connected to the moving iron core 4. The upper end of the drive shaft 5 passes through the through-hole 3-1 and the base plate 6 and is connected to the insulating pull rod 16 of the vacuum circuit breaker. The two ends of the trip spring 12 are respectively pressed against the moving iron core 4 and the base plate 6, or against the moving iron core 4 and the static iron core.

[0024] When closing, refer to Figure 2 , the magnetic field generated by the closing coil 9 is energized to form a closing magnetic circuit 13 on the static iron core 3 and the moving iron core 4, so that the moving iron core 4 overcomes the resistance of the opening spring 12 and is attracted to the static iron core 3 and drives the drive shaft 5 to move upward to complete the closing. After the closing is completed and the power is turned off, the magnetic field generated by the permanent magnet 2 forms a double holding magnetic circuit with the static iron core 3, the moving iron core 4 and the annular magnetic yoke 1 ( Figure 2 14 and 15) keep the switch in the closed state;

[0025] When opening, refer to Figure 1 The direction of the magnetic field generated by the reverse power supply of the opening coil 7 is opposite to the direction of the magnetic field generated by the permanent magnet 2, which weakens the magnetic force generated by the permanent magnet. When the magnetic force is less than the closing holding force of the circuit breaker, under the joint action of the contact spring 17 and the opening spring 12, the moving iron core 4 drives the drive shaft 5 to move downward to complete the opening.

[0026] Reference Figure 1 、 5To further shorten the tripping time, the coil bobbin 8 has an annular groove 8-2 on its lower end surface, within which a repulsion coil 10 is wound. A repulsion disk 11 is installed on the movable iron core 4, opposite the repulsion coil 10. When power is supplied to the repulsion coil 10 and the tripping coil 7 simultaneously, the electromagnetic repulsion generated by the eddy current effect of the repulsion coil 10 pushes the repulsion disk 11 downward, accelerating the downward movement of the movable iron core 4 and, in turn, rapidly moving the drive shaft 5 downward, achieving a rapid tripping time of 1-3 ms.

[0027] Reference Figure 4 In order to further reduce the height of the permanent magnet operating mechanism, an annular groove 4-2 is provided on the moving iron core 4 at a position relative to the repulsion coil 10, and the repulsion disk 11 is annular and fixed in the annular groove 4-2.

[0028] Reference Figure 3 For ease of assembly, an annular shoulder 3-2 is provided on the outer periphery of the open end of the static iron core 3. The permanent magnet 2 is annular and is sleeved on the outer periphery of the static iron core 3, and its lower end is seated on the annular shoulder 3-2.

[0029] In order to keep the switch in the closed state, the double holding magnetic circuit ( Figure 2 14 and 15 ) have uniform magnetic lines of force, and an annular recess 4 - 3 is provided on the movable iron core 4 at a position relative to the permanent magnet 2 .

[0030] In specific implementation, the annular magnetic yoke 1 and the static iron core 3 are fixedly connected to the bottom of the base plate 6 by screws 18. The lower end of the driving shaft 5 has an external thread, and the lower end of the driving shaft 5 is threadedly connected to the moving iron core 4 and fixed by a nut 19.

[0031] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, all equivalent changes made to the contents described in the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A permanent magnetic operating mechanism for a vacuum circuit breaker, characterized in that: The invention comprises a base plate (6), an annular magnetic yoke (1) and a static iron core (3) are fixed below the base plate (6), and the static iron core (3) is coaxially arranged in the inner cavity of the annular magnetic yoke (1); the static iron core (3) is an annular structure with a closed upper end and an open lower end, and a through hole (3-1) is provided at the center of the upper end; a tripping coil (7) and a permanent magnet (2) are provided between the static iron core (3) and the annular magnetic yoke (1), and the tripping coil (7) is located above the permanent magnet (2); a coil frame (8) is provided in the inner cavity of the static iron core (3), and a closing coil (9) is wound on the coil frame (8); A moving iron core (4) is provided below the static iron core (3) and the annular magnetic yoke (1); the moving iron core (4) is in an inverted T-shaped structure, and its vertical end is in a cylindrical structure (4-1) and is inserted into the through hole (8-1) in the center of the coil frame (8); a trip spring (12) is installed in the cylindrical structure (4-1); the lower end of the driving shaft (5) passes through the trip spring (12) and is fixedly connected to the moving iron core (4); the upper end of the driving shaft (5) passes through the through hole (3-1) and the base plate (6) and is connected to the insulating pull rod (16) of the vacuum circuit breaker, and the two ends of the trip spring (12) are respectively pressed against the moving iron core (4) and the base plate (6); When closing, the magnetic field generated by the closing coil (9) when energized forms a closing magnetic circuit (13) on the static iron core (3) and the moving iron core (4), causing the moving iron core (4) to overcome the resistance of the opening spring (12) and attract the static iron core (3) and drive the drive shaft (5) upward to complete the closing. After the closing is completed and the power is turned off, the magnetic field generated by the permanent magnet (2) forms a double holding magnetic circuit with the static iron (3), the moving iron core (4) and the annular magnetic yoke (1) to maintain the closed state. When opening, the magnetic field generated by the opening coil (7) when reversely energized weakens the magnetic force of the permanent magnet (2) so that it is less than the closing holding force of the circuit breaker. Under the joint action of the contact spring (17) and the opening spring (12), the moving iron core (4) drives the drive shaft (5) downward to complete the opening.

2. The permanent magnetic operating mechanism for vacuum circuit breaker according to claim 1, characterized in that: The lower end surface of the coil frame (8) is provided with an annular groove (8-2), and a repulsion coil (10) is wound in the annular groove (8-2); a repulsion disk (11) is provided on the moving iron core (4) at a position relative to the repulsion coil (10).

3. The permanent magnetic operating mechanism for vacuum circuit breaker according to claim 2, characterized in that: An annular recessed groove (4-2) is provided on the moving iron core (4) at a position relative to the repulsion coil (10), and the repulsion disc (11) is annular and fixed in the annular recessed groove (4-2).

4. The permanent magnetic operating mechanism for vacuum circuit breaker according to claim 1, characterized in that: An annular shoulder (3-2) is provided on the outer periphery of the open end of the static iron core (3); the permanent magnet (2) is annular and is sleeved on the outer periphery of the static iron core (3), with its lower end seated on the annular shoulder (3-2).

5. The permanent magnetic operating mechanism for vacuum circuit breaker according to claim 3, characterized in that: A second annular recessed groove (4-3) is provided on the moving iron core (4) at a position relative to the permanent magnet (2).

6. The permanent magnetic operating mechanism for vacuum circuit breaker according to claim 1, characterized in that: The substrate (6) is made of non-magnetic material.

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