An insulating pull rod capable of suppressing bouncing

Abstract

An insulating pull rod capable of suppressing bounce comprises an insulating body (1) and a connecting rod (5), wherein a metal sleeve (2) and a metal connector (3) are respectively embedded at both ends of the insulating body (1), a contact spring (4) is installed in the metal sleeve (2), and the lower end of the connecting rod (5) is press-fitted into the metal sleeve (2) and located above the contact spring (4); a damper (7) is provided in the metal sleeve (2), and the damper (7) is located in the inner cavity of the contact spring (4), and the upper end of the damper (7) abuts against the lower end of the connecting rod (5), and the lower end abuts against the bottom surface of the metal sleeve (2). When the moving and static contacts of the circuit breaker are impacted and the moving contact bounces open, the damper instantly generates a reaction force to resist the bounce of the moving contact, and the bounce of the moving contact is suppressed by the superposition of this reaction force and the initial pressure of the contact spring.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit breakers, and in particular relates to an insulating pull rod capable of suppressing bouncing. Background Art

[0002] Circuit breaker closing bounce occurs when the moving contact of the interrupter hits the stationary contact of the interrupter during closing, causing an elastic collision and causing the moving contact to bounce away from the stationary contact. The operating mechanism then allows the moving contact to continue closing until it collides with the stationary contact and is no longer able to bounce away.

[0003] In the prior art, the operating mechanism is connected to the moving contact via an insulating rod. To suppress bounce, this is often accomplished by installing a contact spring on the insulating rod. This contact spring continues to exert force on the moving contact after the moving and static contacts make contact, creating a high contact pressure on the moving contact and reducing bounce when the moving and static contacts close. The specific principle is that when the moving contact is opened, the contact spring is compressed. If the rebound force is less than the contact spring force, the moving contact will not be opened. If the rebound force is greater than the contact spring force, the moving contact will be opened. Therefore, increasing the contact spring force can suppress bounce. The magnitude of the contact spring force is determined by the electromotive force of the circuit breaker's dynamic stability current. Increasing the contact spring force to suppress bounce is unreasonable. This would result in the following adverse consequences: 1) increasing the closing energy, making the operating mechanism larger; 2) increasing the impact of the mechanism's opening and closing operations, affecting the operating mechanism's lifespan and reliability; and 3) increasing the impact on the arc extinguishing chamber, affecting its lifespan and reliability.

[0004] The contact spring force in the insulating pull rod is the initial pressure when it is first compressed, which is used to resist the rebound force of the moving contact. The force after a certain overstroke is the final pressure. This force is determined by the rated short-time impulse current index of the circuit breaker (see Figure 4 In current vacuum circuit breakers, if the final pressure is used to determine the contact spring force, the initial pressure often cannot suppress bounce. If the initial pressure used to suppress bounce is used to determine the contact spring force, the final pressure will be much greater than the force determined by the circuit breaker's rated short-time inrush current, with an overall negative effect. Summary of the Invention

[0005] The present invention provides an insulating pull rod capable of suppressing bouncing, so as to overcome the deficiencies of the prior art.

[0006] The technical solution adopted by the present invention is: an insulating pull rod capable of suppressing bounce, comprising an insulating body and a connecting rod, wherein a metal sleeve and a metal connector are respectively embedded at both ends of the insulating body, a contact spring is installed in the metal sleeve, and the lower end of the connecting rod is pressed into the metal sleeve and located above the contact spring; a damper is provided in the metal sleeve, the damper is located in the inner cavity of the contact spring, and the upper end of the damper is against the lower end of the connecting rod, and the lower end is against the bottom surface of the metal sleeve.

[0007] Preferably, the damper is a hydraulic damper, and the movable end of the hydraulic damper abuts against the bottom surface of the metal sleeve, and the static end of the hydraulic damper abuts against the lower end of the connecting rod.

[0008] Furthermore, the lower end of the connecting rod has a countersunk hole in the axial direction, and the static end of the hydraulic damper is inserted into the countersunk hole.

[0009] Furthermore, the outer periphery of the lower end of the connecting rod is provided with an annular shoulder, and a pressure ring is sleeved on the annular shoulder. The lower end of the connecting rod is pressed into the metal sleeve through the threaded connection between the pressure ring and the metal sleeve.

[0010] Furthermore, the hydraulic damper includes a piston, a piston rod, an oil cylinder and a damping spring. The piston and damping spring are arranged in the oil cylinder, and the damping spring is located above the piston, and the two ends of the damping spring are respectively against the top of the oil cylinder and the upper end of the piston; the piston rod is fixedly connected to the bottom of the piston and extends out of the oil cylinder; the upper end of the oil cylinder serves as the static end of the hydraulic damper, and the lower end of the piston rod serves as the dynamic end of the hydraulic damper.

[0011] Preferably, the upper end of the oil cylinder has a necking section, and the outer diameter of the necking section is adapted to the inner diameter of the countersunk hole, and the length of the necking section is ≤ the depth of the countersunk hole.

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

[0013] 1. The present invention adds a damper to the insulating pull rod of the existing structure. When the moving and static contacts of the circuit breaker impact and the moving contact bounces, the damper instantly generates a reaction force to resist the bounce of the moving contact. The reaction force is superimposed on the initial pressure of the contact spring to suppress the bounce of the moving contact.

[0014] 2. The present invention does not need to increase the contact spring force in the existing insulating pull rod structure to suppress the bounce of the moving contact, thus overcoming the adverse consequences of suppressing the bounce by increasing the contact spring force.

[0015] 3. The damper of the present invention uses a hydraulic damper. When the circuit breaker closes and overtravels, the hydraulic damping force is very small and can be ignored compared to the contact spring force. Therefore, the hydraulic damper does not affect the closing action of the circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural cross-sectional view of the present invention;

[0017] Figure 2 Schematic diagram of the appearance structure of the hydraulic damper of the present invention;

[0018] Figure 3 This is a cross-sectional view of the hydraulic damper structure of the present invention;

[0019] Figure 4 is the FS curve diagram of the contact spring;

[0020] Figure 5 It is the FS curve diagram of the hydraulic damper;

[0021] Figure 6 It is the FS curve diagram of the present invention. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-3 The present invention is described in detail with specific embodiments.

[0023] An insulating pull rod capable of suppressing bounce comprises an insulating body 1 and a connecting rod 5, wherein a metal sleeve 2 and a metal connector 3 are respectively embedded at both ends of the insulating body 1, a contact spring 4 is installed in the metal sleeve 2, and the lower end of the connecting rod 5 is pressed into the metal sleeve 2 and located above the contact spring 4. A damper 7 is provided in the metal sleeve 2, and the damper 7 is located in the inner cavity of the contact spring 4, and the upper end of the damper 7 is against the lower end of the connecting rod 5, and the lower end is against the bottom surface of the metal sleeve 2.

[0024] In one embodiment, the outer periphery of the lower end of the connecting rod 5 has an annular shoulder 5-2, and a pressure ring 6 is mounted above the annular shoulder 5-2. The lower end of the connecting rod 5 is pressed into the metal sleeve 2 by threading the pressure ring 6 with the metal sleeve 2.

[0025] In one embodiment, the damper 7 is preferably a hydraulic damper, and the movable end of the hydraulic damper abuts against the bottom surface of the metal sleeve 2 , and the static end of the hydraulic damper abuts against the lower end of the connecting rod 5 .

[0026] Preferably, the lower end of the connecting rod 5 has an axial countersunk hole 5 - 1 , and the static end of the hydraulic damper is inserted into the countersunk hole 5 - 1 .

[0027] Furthermore, the hydraulic damper includes a piston 7-1, a piston rod 7-2, a cylinder 7-3 and a return spring 7-4. The piston 7-1 and the damping spring 7-4 are arranged in the cylinder 7-3, and the damping spring 7-4 is located above the piston 7-1, and the two ends of the damping spring 7-4 are respectively against the top of the cylinder 7-3 and the upper end of the piston 7-1; the piston rod 7-2 is fixedly connected to the bottom of the piston 7-1 and extends out of the cylinder 7-3; the upper end of the cylinder 7-3 serves as the static end of the hydraulic damper, and the lower end of the piston rod 7-2 serves as the dynamic end of the hydraulic damper.

[0028] Preferably, the upper end of the oil cylinder 7-3 has a necking section 7-5, and the outer diameter of the necking section 7-5 is adapted to the inner diameter of the countersunk hole 5-1, and the length of the necking section 7-5 is ≤ the depth of the countersunk hole 5-1, making the assembly and positioning of the hydraulic damper more convenient and quick.

[0029] When the present invention is in use, the connecting rod 5 is connected to the moving contact of the circuit breaker, and the metal connector 3 is connected to the operating mechanism of the circuit breaker through the connecting screw. When the moving and static contacts of the circuit breaker impact and the moving contact bounces open, the hydraulic damper instantly generates a reaction force to resist the bounce of the moving contact, and this reaction force, when added to the initial pressure of the contact spring, is greater than the rebound force of the moving contact (see Figure 6 ), achieving the goal of suppressing moving contact bounce without increasing the contact spring force in the existing insulating pull rod structure. After the circuit breaker is closed, the piston in the hydraulic damper is reset by the damping spring.

[0030] The hydraulic damping force of the hydraulic damper is related to the acceleration of the piston in the cylinder. The greater the acceleration, the greater the damping force, and the smaller the acceleration, the smaller the damping force (see Figure 5 When the moving and static contacts impact, the instantaneous acceleration is high, resulting in a large damping force. When the circuit breaker closes and overtravels, the acceleration of the compressed piston in the hydraulic damper is minimal, resulting in a very small hydraulic damping force, negligible compared to the contact spring force. Therefore, the hydraulic damper does not affect the circuit breaker's closing action.

[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. An insulating pull rod capable of suppressing bounce, comprising an insulating body (1) and a connecting rod (5), wherein a metal sleeve (2) and a metal connecting piece (3) are respectively embedded at both ends of the insulating body (1), a contact spring (4) is installed in the metal sleeve (2), the lower end of the connecting rod (5) is press-fitted into the metal sleeve (2) and is located above the contact spring (4), the connecting rod (5) is connected to the moving contact of the circuit breaker, and the metal connecting piece (3) is connected to the operating mechanism of the circuit breaker via a connecting screw; and the invention is characterized in that: A damper (7) is provided in the metal sleeve (2), and the damper (7) is located in the inner cavity of the contact spring (4), and the upper end of the damper (7) abuts against the lower end of the connecting rod (5), and the lower end abuts against the bottom surface of the metal sleeve (2); The damper (7) is a hydraulic damper, and the movable end of the hydraulic damper abuts against the bottom surface of the metal sleeve (2), and the static end of the hydraulic damper abuts against the lower end of the connecting rod (5); The hydraulic damper comprises a piston (7-1), a piston rod (7-2), and an oil cylinder (7-3); the piston (7-1) is arranged in the oil cylinder (7-3); the piston rod (7-2) is fixedly connected to the bottom of the piston (7-1) and extends out of the oil cylinder (7-3); the upper end of the oil cylinder (7-3) serves as the static end of the hydraulic damper, and the lower end of the piston rod (7-2) serves as the dynamic end of the hydraulic damper; The lower end of the connecting rod (5) is axially provided with a countersunk hole (5-1), and the static end of the hydraulic damper is inserted into the countersunk hole (5-1); The lower end of the connecting rod (5) is provided with an annular shoulder (5-2) on its periphery, and a pressing ring (6) is sleeved on the upper portion of the annular shoulder (5-2). The lower end of the connecting rod (5) is pressed into the metal sleeve (2) by threaded connection between the pressing ring (6) and the metal sleeve (2).

2. The insulating pull rod capable of suppressing bounce according to claim 1, characterized in that: A damping spring (7-4) is also provided in the oil cylinder (7-3), and the damping spring (7-4) is located above the piston (7-1), with both ends of the damping spring (7-4) respectively abutting against the top of the oil cylinder (7-3) and the upper end of the piston (7-1).

3. The insulating pull rod capable of suppressing bounce according to claim 1, characterized in that: The upper end of the oil cylinder (7-3) has a necking section (7-5), and the outer diameter of the necking section (7-5) is adapted to the inner diameter of the countersunk hole (5-1), and the length of the necking section (7-5) is less than or equal to the depth of the countersunk hole (5-1).

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