Vacuum circuit breaker and transmission mechanism thereof

Abstract

The utility model relates to a vacuum circuit breaker and a transmission mechanism thereof. The vacuum circuit breaker comprises an operating mechanism and a switch unit which is controlled by the operating mechanism to open and close. The transmission mechanism is suitable for being connected between the operation mechanism and the switch unit. The transmission mechanism comprises a first main shaft which can rotate around the central axis of the first main shaft and is suitable for being operably connected to the operation mechanism; the second main shaft and the first main shaft are arranged in parallel and at an interval; the connecting rod mechanism is connected between the first main shaft and the second main shaft and connected between the second main shaft and the switch unit, and the connecting rod mechanism is configured to be located at a dead point position when the switch unit is in a closed state; and the switch unit can be driven by the operating mechanism to cross the dead point position so as to allow the switch unit to be switched off.

Description

Technical Field

[0001] This utility model relates to the field of vacuum switchgear technology, and in particular to vacuum circuit breakers and their transmission mechanisms. Background Technology

[0002] As a core switching device in medium- and high-voltage power systems, the closing stability of vacuum circuit breakers directly impacts grid security. Traditional vacuum circuit breaker transmission mechanisms often employ a single-spindle drive linkage structure. During closing, the operating mechanism (such as a spring mechanism) drives the crank arm and pull rod via the spindle, pushing the moving contact to close. However, the electrodynamic force (such as Holm force and Lorentz force) generated by the current flowing through the contacts at the moment of contact closure induces a repulsive force, causing the moving contact to move in the opposite direction. If this reverse thrust is transmitted back to the operating mechanism via the transmission chain, it will cause wear or even failure of the mechanism components, reducing the equipment's lifespan.

[0003] In existing technologies, mechanical interlocking or hydraulic buffering devices are typically used to suppress the transmission of recoil force. However, such solutions suffer from drawbacks such as complex structure, slow response, or high maintenance costs. For example, a known anti-rebound mechanism for vacuum circuit breakers achieves interlocking through an additional spring and slot, but this requires extra space and is prone to failure due to spring fatigue. A hydraulic contact repulsion buffering device is also known, which can absorb recoil energy, but increases sealing requirements and the risk of failure.

[0004] Therefore, there is an urgent need for a vacuum switchgear that is compact in structure, can actively block the transmission of reverse thrust, and increases the stability of closing. Summary of the Invention

[0005] The present invention aims to provide a transmission mechanism for a vacuum circuit breaker, which can at least solve some of the above-mentioned technical problems.

[0006] This invention also aims to provide a vacuum circuit breaker that utilizes the aforementioned improved transmission mechanism.

[0007] According to one aspect of the present invention, a transmission mechanism for a vacuum circuit breaker is provided. The vacuum circuit breaker includes an operating mechanism and a switching unit controlled by the operating mechanism for opening and closing. The transmission mechanism is adapted to be connected between the operating mechanism and the switching unit. The transmission mechanism includes: a first main shaft rotatable about its own central axis and adapted to be operably connected to the operating mechanism; a second main shaft arranged parallel to and spaced apart from the first main shaft; and a linkage mechanism connected between the first main shaft and the second main shaft, and connected between the second main shaft and the switching unit. The linkage mechanism is configured to be in a dead position when the switching unit is in a closed state, and to be able to pass the dead position under the drive of the operating mechanism to allow the switching unit to open.

[0008] The transmission mechanism provided in this solution connects the operating mechanism of the vacuum circuit breaker to the vacuum switch unit, transmitting the actions of the operating mechanism to the vacuum switch unit to control its opening and closing. This transmission mechanism features dual main shafts and a self-locking mechanism achieved by designing the linkage to be in a dead position during vacuum switch unit closing, ensuring the moving contact rod remains locked before opening. Therefore, the electro-repulsive force generated between the moving and stationary contacts during closing is not transmitted back to the operating mechanism, improving the safety of the operating mechanism while meeting transmission requirements. This transmission mechanism offers high reliability and requires no additional buffer components. The purely mechanical structure provides strong fatigue resistance, reducing the frequency of equipment maintenance throughout its lifespan.

[0009] In some embodiments, the linkage mechanism includes: a first crank arm rotatably connected to the first main shaft about its central axis; a second crank arm rotatably connected to the second main shaft about its central axis; a beam rotatably disposed about a fixed crossbar; a first transmission rod hinged between the first crank arm and the second crank arm; a second transmission rod hinged between the second crank arm and the beam; and a third transmission rod hinged between the beam and the switching unit, wherein the third transmission rod and the second transmission rod are located on opposite sides of the crossbar; wherein the second transmission rod can move to the dead center position under the drive of the second crank arm.

[0010] In some embodiments, the second crank arm has a first arm segment extending from the rotation center of the second crank arm, and when the first arm segment is collinear with the second transmission rod, the second transmission rod moves to the dead point position.

[0011] In some embodiments, the second crank arm has a second arm segment extending from the rotation center of the second crank arm and angled to the first arm segment, and the first drive rod is hinged to the second arm segment.

[0012] In some embodiments, the angle between the first arm segment and the second arm segment is between 90° and 120°.

[0013] In some embodiments, the switching unit includes an insulating pull rod connected to a moving contact, and the third transmission rod is hinged between the insulating pull rod and the beam.

[0014] In some embodiments, a single longitudinal first main shaft is adapted to drive a linkage mechanism of multiple switching units of the vacuum circuit breaker.

[0015] In some embodiments, a single longitudinal second main shaft is adapted to be connected to a linkage mechanism of multiple switching units of the vacuum circuit breaker.

[0016] According to another aspect of the present invention, a vacuum circuit breaker is provided, including an operating mechanism and at least one switching unit controlled by the operating mechanism for opening and closing, and further including a transmission mechanism connected between the operating mechanism and the at least one switching unit, the transmission mechanism being the aforementioned transmission mechanism, wherein the at least one switching unit is connected to a common first spindle and a second spindle via respective linkage mechanisms.

[0017] Other features and advantages of this invention will partly be apparent to those skilled in the art upon reading this application, and partly will be described below in conjunction with the accompanying drawings in the detailed description. Attached Figure Description

[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0019] Figure 1 This is a schematic diagram of a vacuum circuit breaker according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a vacuum circuit breaker according to an embodiment of the present invention, in which the housing of one of the switching units is removed to expose the vacuum switch therein;

[0021] Figure 3 This is a schematic diagram of the transmission mechanism and switching unit according to an embodiment of the present utility model;

[0022] Figure 4 This is a schematic diagram of the transmission mechanism and switching unit according to an embodiment of the present utility model, wherein the switching unit is in the open state;

[0023] Figure 5 This is a schematic diagram of the transmission mechanism and switching unit according to an embodiment of the present utility model, wherein the switching unit is in the closed state.

[0024] Explanation of reference numerals in the attached figures

[0025] 1-Vacuum circuit breaker; 2-Operating mechanism; 3-Transmission mechanism; 30-First main shaft; 31-Second main shaft; 32-First crank arm; 33-First transmission rod; 34-Second crank arm; 341-First arm section; 342-Second arm section; 35-Second transmission rod; 36-Beam; 37-Third transmission rod; 38-Crossbeam; 4-Switch unit; 40-Housing; 41-Vacuum switch; 42-Insulating pull rod; 43-First terminal block; 44-Flexible connection; 45-Second terminal block Detailed Implementation

[0026] The schematic solutions of the technical solutions disclosed in this utility model are now described in detail with reference to the accompanying drawings. Although the drawings are provided to illustrate some embodiments of this utility model, the drawings are not necessarily drawn to the dimensions of the specific embodiments, and certain features may be enlarged, removed, or partially cut to better illustrate and explain the disclosure of this utility model. Some components in the drawings may be repositioned according to actual needs without affecting the technical effect. The phrase "in the drawings" or similar terms appearing in the specification do not necessarily refer to all drawings or examples.

[0027] Certain directional terms used in the description of the accompanying drawings below, such as “inner,” “outer,” “above,” “below,” and other directional terms, will be understood to have their normal meaning and refer to those directions as normally viewed in the accompanying drawings. Unless otherwise specified, the directional terms used in this specification are generally in accordance with the conventional directions understood by those skilled in the art.

[0028] The terms “first,” “first,” “second,” “second,” and similar terms used in this utility model do not indicate any order, quantity, or importance, but are used to distinguish one component from other components.

[0029] Vacuum circuit breakers are a type of switching equipment widely used in power systems. They mainly control the opening and closing of circuits by opening and closing moving contacts and stationary contacts. Figure 1 and Figure 2 An exemplary vacuum circuit breaker 1 is shown, mainly comprising an operating mechanism 2, a transmission mechanism 3, and switching units 4. Multiple switching units 4 are each connected to the operating mechanism 2 via the transmission mechanism 3, and can uniformly perform opening or closing actions under the control of the operating mechanism 2. The operating mechanism 2 can employ various existing structures, such as a spring-energy-storage operating mechanism, which mainly includes an energy-storage spring, a motor, a manual energy storage device, and a tripping device. The energy-storage spring stores mechanical energy and provides the power required for opening and closing. The motor and the manual energy storage device compress the energy-storage spring to achieve an energy-storage state. The tripping device actuates upon receiving an opening signal to release the energy of the energy-storage spring.

[0030] like Figure 2In more detail, multiple switching units 4 (three shown in the figure) are connected in parallel to the operating mechanism 2. Each switching unit 4 includes a housing 40 and a vacuum switch 41 housed within the housing 40. The vacuum switch 41 includes a robust housing and moving and stationary contacts sealed within the housing. One end of an insulating rod 42 extends into the housing and connects to the moving contact, while the other end extends out of the housing and is connected to the operating mechanism 2 via a transmission mechanism 3. Under the control of the operating mechanism 2, the insulating rod 42 can push the moving contact to move close to and engage with the stationary contact to close the vacuum circuit breaker, and can also pull the moving contact to move away from the stationary contact to open the vacuum circuit breaker. The insulating rod 42 is connected to a first terminal 43 via a flexible connection 44, and the first terminal 43 is mounted to the housing 40. The stationary contact of the vacuum switch 41 is connected to a second terminal 45 located outside the housing, and the second terminal 45 is mounted to the housing 40. The vacuum circuit breaker 1 can be connected to a circuit via the first terminal 43 and the second terminal 45.

[0031] The specific structure of transmission mechanism 3 is shown in Figures 3 to 5 As shown in the figure, the transmission mechanism 3 of this utility model adopts a dual-spindle design and has a locking function during the closing of the vacuum circuit breaker 1, so as to keep the insulating pull rod of the moving contact locked before the moving contact and the stationary contact are separated, and prevent the back thrust between the contacts from being transmitted to the operating mechanism 2.

[0032] In the illustrated embodiment, the two spindles, namely the first spindle 30 and the second spindle 31, are arranged parallel and spaced apart. The first spindle 30 and the second spindle 31 extend laterally through the vacuum circuit breaker, and each spindle is supported at its two ends by bearings. The first spindle 30 is connected to the operating mechanism 10 and receives its rotational driving force. For the entire vacuum circuit breaker 1, a single first spindle 30 and a single second spindle 40 are provided for all switching units 4. This allows for the provision of support frames only at the ends of the first spindle 30 and the second spindle 31, or the formation of receiving holes only on the housings 40 of the two outermost switching units 4 to mount the first spindle 30 and the second spindle 31. Connecting multiple switching units 4 in parallel to the same first spindle 30 and second spindle 40 also helps to improve the uniformity of the operation of these switching units 4. After long-term operation of the power equipment, wear inevitably leads to misalignment between the moving parts of the operating mechanism 2, the transmission mechanism 3, and the switching units 4. Connecting multiple switch units 4 to a common first spindle 30 and second spindle 31 can effectively avoid inconsistent opening and closing actions of each switch unit 4 due to unbalanced coordination errors, thereby improving the stability and reliability of the vacuum circuit breaker 1.

[0033] The first main shaft 30 is connected to the operating mechanism 2 and can rotate around its own central axis in response to the action of the operating mechanism 2 to drive the moving contacts of each switch unit 4. Each switch unit 4 is connected to the common first main shaft 30 and second main shaft 31 through its own linkage mechanism, and the linkage mechanisms of each switch unit 4 are arranged axially spaced along the first main shaft 30 and also axially spaced along the second main shaft 31. In the illustrated embodiment, the linkage mechanism of each switch unit 4 is a planar linkage mechanism, including a first crank arm 32, a second crank arm 34, and multiple transmission rods 33, 35, and 36.

[0034] The first crank arm 32 is sleeved on the first main shaft 30 and is almost immovable relative to the first main shaft 30, thereby being able to rotate about the central axis of the first main shaft 30 as the first main shaft 30 rotates. The first crank arm 32 has an arm segment extending radially along the first main shaft 30, wherein the first end of the first drive rod 33 is hinged to the end of the arm segment away from the first main shaft 30 by a pin.

[0035] The second crank arm 34 is sleeved on the second main shaft 31 and is rotatable about the central axis of the second main shaft 31. The second crank arm 34 is V-shaped and includes a first arm segment 341 extending radially along the second main shaft 31 and a second arm segment 342 extending radially along the second main shaft 31 at an angle relative to the first arm segment 341. The angle between the first arm segment 341 and the second arm segment 342 can be selected between 90° and 120° to ensure efficient force transmission. The second end of the first transmission rod 33, opposite to the first end, is hinged to the end of the second arm segment 342 away from the second main shaft 31 by a pin, while the first end of the second transmission rod 35 is hinged to the end of the first arm segment 341 away from the second main shaft 31 by a pin. In the illustrated embodiment, the first transmission rod 33 may be a two-piece structure, with the first crank arm 32 and the second crank arm 34 sandwiched between the two pieces.

[0036] A crossbar 38 is installed on the inner wall of the housing 40 of the switching unit 4. This crossbar 38 is parallel to the first main shaft 30 and the second main shaft 31. A beam 36 is sleeved on the crossbar 38 and can rotate about the central axis of the crossbar 38. The second end of the second transmission rod 35, opposite to the first end, is hinged to the first end of the beam 36 by a pin. For stability, the beam 36 can be constructed as a double-piece structure, with multiple reinforcing rods parallel to the crossbar 38 spaced between the two pieces. The second transmission rod 35 can also be constructed as a double-piece structure, with the double pieces forming a widened fork shape at the end near the beam 36 to accommodate the distance between the double pieces of the beam 36. At the end near the second crank arm 34, the double pieces of the second transmission rod 35 clamp the second crank arm 34 between them.

[0037] A third transmission rod 37 is hinged to the second end of beam 36, opposite to the first end, via a pin. The first and second ends of beam 36 are located on opposite sides of crossbar 38. This arrangement of the third transmission rod 37 and the second transmission rod 35 on opposite sides of crossbar 38 facilitates torque balance. The third transmission rod 37 is also hinged to the insulating pull rod 42 of switch unit 4 via a pin. Thus, a transmission chain is formed between the moving contact of switch unit 4 and operating mechanism 2. When the second transmission rod 35 moves to a position collinear with the first arm segment 341 of the second crank arm 34, the linkage mechanism is at a dead position and self-locked. At this time, the contact repulsion force forms an internal force closed loop through beam 36 and the second transmission rod 35, locking the insulating pull rod 42 of switch unit 4. The closing repulsion force generated on one side of switch unit 4 cannot return to operating mechanism 2 through the transmission chain, thereby blocking the counter-thrust force.

[0038] The closing process of vacuum circuit breaker 1 is as follows:

[0039] Operating mechanism 2 drives the first main shaft 30 to rotate clockwise as shown in the figure, driving the first crank arm 32 to rotate synchronously with the first main shaft 30. The first crank arm 32 pushes the second crank arm 34 to rotate clockwise around the second main shaft 31 through the first transmission rod 33, so that the second crank arm 34 drives the second transmission rod 33. With the movement of the second transmission rod 33, the beam 36 rotates around the crossbar 38, its first end is lifted, and its second end is pressed down. The third transmission rod 53 converts the rotation of the beam 43 into the linear descent of the insulating pull rod 42, driving the moving contact to close with the stationary contact. When the closing position is reached, the first arm segment 341 of the second crank arm 34 is collinear with the second transmission rod 35 (e.g., Figure 4 (As shown in the dead point position), at this time the transmission mechanism 3 is in a self-locking state, and the contact repulsion force cannot be transmitted in the reverse direction to the first main shaft 30 through the beam 38.

[0040] The opening process of vacuum circuit breaker 1 is as follows:

[0041] The operating mechanism 10 reverses the drive of the first main shaft 30, causing the first crank arm 32 to pull the second crank arm 34 past the dead point position via the first transmission rod 33. The second transmission rod 35 and the first arm segment 341 of the second crank arm 34 are discontinuing their collinearity. Under the tension of the second transmission rod 35, the beam 36 swings back, causing the first end to descend and the second end to rise. The third transmission rod 37 can then lift the insulating pull rod 42 to achieve circuit breaking.

[0042] The dual-spindle design ensures that when the operating mechanism 2 drives the first spindle 30, the linkage mechanisms of all switching units 4 operate synchronously, ensuring the synchronicity of multi-break closing. Furthermore, the contact repulsion force of each break is independently blocked by the corresponding dead-point structure, preventing interference. The shared dual spindles also achieve a compact layout, reducing manufacturing and commissioning costs.

[0043] It should be understood that although this specification describes various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0044] The above description is merely an illustrative embodiment of this utility model and is not intended to limit the scope of this utility model. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. A transmission mechanism of a vacuum circuit breaker including an operating mechanism and a switch unit whose opening and closing are controlled by the operating mechanism, the transmission mechanism being adapted to be connected between the operating mechanism and the switch unit, characterized in that, The transmission mechanism comprises: a first spindle rotatable about a central axis thereof and adapted to be operatively connected to the operating mechanism; a second spindle arranged in parallel with and spaced from the first spindle; a linkage connected between the first spindle and the second spindle and connected between the second spindle and the switch unit, wherein the linkage is configured to be at a dead center position when the switch unit is in a closed state and is drivable beyond the dead center position by the operating mechanism to allow the switch unit to be opened.

2. The drive mechanism of the vacuum circuit breaker according to claim 1, characterized in that, The linkage comprises: a first bell crank rotatably connected to the first spindle about a central axis of the first spindle; a second bell crank rotatably connected to the second spindle about a central axis of the second spindle; a beam rotatably arranged about a fixed crossbar; a first transmission rod hingedly connected between the first bell crank and the second bell crank; a second transmission rod hingedly connected between the second bell crank and the beam; a third transmission rod hingedly connected between the beam and the switch unit, wherein the third transmission rod is located on an opposite side of the crossbar from the second transmission rod; wherein the second transmission rod is drivable to the dead center position by the second bell crank.

3. The drive mechanism of the vacuum circuit breaker according to claim 2, characterized in that, The second bell crank has a first arm segment extending from a rotation center of the second bell crank, and the second transmission rod is driven to the dead center position when the first arm segment is collinear with the second transmission rod.

4. The drive mechanism of the vacuum circuit breaker according to claim 3, characterized in that, The second bell crank has a second arm segment extending from the rotation center of the second bell crank and being at an angle to the first arm segment, and the first transmission rod is hingedly connected to the second arm segment.

5. The drive mechanism of the vacuum circuit breaker according to claim 4, characterized in that, The angle between the first arm segment and the second arm segment is 90°-120°.

6. The drive mechanism of the vacuum circuit breaker according to claim 2, characterized in that, The switch unit comprises an insulating pull rod connected to a movable contact, and the third transmission rod is hingedly connected between the insulating pull rod and the beam.

7. The drive mechanism of the vacuum circuit breaker according to claim 1, characterized in that, A whole longitudinal first spindle is adapted to drive linkages of a plurality of switch units of the vacuum circuit breaker.

8. The drive mechanism of the vacuum circuit breaker according to claim 1, characterized in that, A whole longitudinal second spindle is adapted to be connected to linkages of a plurality of switch units of the vacuum circuit breaker.

9. A vacuum circuit breaker comprising an operating mechanism and at least one switching unit controlled by the operating mechanism to open and close, further comprising a transmission mechanism connected between the operating mechanism and the at least one switching unit, characterized in that, The transmission mechanism is any one of claims 1-8, wherein the at least one switch unit is connected to the common first spindle and the common second spindle by respective linkages.

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