Low-voltage circuit breaker

Abstract

According to the technical scheme, the low-voltage circuit breaker is characterized in that the low-voltage circuit breaker comprises a shell, a contact mechanism and an operating mechanism, the contact mechanism comprises a moving contact and a static contact, and the moving contact is provided with a compensation head and a compensation mechanism; an expansion cavity, an operation cavity and a moving cavity are sequentially arranged in the moving contact, the compensation head is slidably connected in the moving cavity, the compensation mechanism comprises an expansion part, a driving part and a driving spring, and the expansion part is arranged in the expansion cavity; the driving part is arranged in the operation cavity, a first driving plate and a second driving plate which are in linkage with the driving part are arranged in the operation cavity, the driving spring is arranged in the moving cavity, and one end of the first driving plate is located in the expansion cavity; the driving component at least comprises a cam, the cam is provided with a progressive increase surface and a progressive decrease surface, the second driving plate and the cam are arranged in a linkage mode, and the circuit breaker can keep abutting against the static contact when the temperature of the moving contact rises normally, and can break abutting against the static contact when the temperature of the moving contact rises abnormally.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit breakers, and more particularly to a low-voltage circuit breaker. Background Art

[0002] Low voltage circuit breakers are key equipment used to control and protect low voltage circuits in power systems. They are widely used in circuits with AC voltages of 1000V and below or DC voltages of 1500V and below. They can automatically cut off the circuit when overload, short circuit, undervoltage and other faults occur in the circuit to prevent equipment damage and accidents from expanding. They can also be used for circuit on-off operations under normal conditions.

[0003] In the prior art, when the low-voltage circuit breaker is in a closed state, the moving contact can be in contact with the static contact and connected. The moving contact is generally subjected to a long-term abutment force by a spring. However, due to poor contact of the moving contact during long-term use or when the electrical power is large and the current flowing through the moving contact is large, the temperature of the moving contact will rise. The high temperature will cause grain boundary sliding of the spring material, resulting in a decrease in the elastic modulus and elastic limit, which will further reduce the pressure between the moving contacts, resulting in poor contact and a vicious cycle. Summary of the invention

[0004] In view of the deficiencies in the prior art, an object of the present invention is to provide a low-voltage circuit breaker, which can maintain abutment with a stationary contact when the temperature of the moving contact rises normally, and can disconnect the abutment with the stationary contact when the temperature of the moving contact rises abnormally.

[0005] To achieve the above object, the present invention provides the following technical solution: a low-voltage circuit breaker, comprising a housing, a contact mechanism and an operating mechanism, wherein the contact mechanism comprises a moving contact and a stationary contact arranged opposite to each other, and the operating mechanism is used to drive the moving contact to contact or separate from the stationary contact; The moving contact is provided with a compensation head and a compensation mechanism; The moving contact is provided with an expansion chamber, an operation chamber and a moving chamber in sequence along its length direction, the compensation head is slidably connected in the moving chamber, the compensation mechanism includes an expansion member, a driving member and a driving spring, and the expansion member is provided in the expansion chamber; The driving component is arranged in the operating chamber, and the operating chamber is provided with a first driving plate and a second driving plate which are arranged in linkage with the driving component, and the driving spring is arranged in the moving chamber and is connected with the second driving plate and the compensation head respectively; One end of the first driving plate is located in the expansion cavity, and when the moving contact is heated, the expansion member pushes the first driving plate to move toward the driving component; The driving component at least includes a cam, and the cam is provided with an increasing surface and a decreasing surface in sequence along its rotation direction. The slope of the decreasing surface is greater than the slope of the increasing surface. The second driving plate is arranged in linkage with the cam.

[0006] The present invention is further configured as follows: the driving component also includes a driving gear and a connecting rod, the driving gear is connected to the cam through the connecting rod, and one end of the first driving plate is provided with an engaging structure that engages with the driving gear.

[0007] The present invention is further configured as follows: the expansion member includes an expansion fluid, the first drive plate includes a sealing plate located in the expansion cavity, a sealing ring is provided on the peripheral side of the sealing plate, and the sealing plate is slidably connected in the sealing cavity.

[0008] The present invention is further configured as follows: a limit block is provided on the cam, the limit block is located on one side of the decreasing surface, a first limit space is formed between the limit block and the decreasing surface, and a second limit space is formed on the side of the limit block away from the decreasing surface; When the expansion member continues to slowly heat up, the second driving plate moves along the decreasing surface to the first limiting space; When the expansion member heats up rapidly, the cam rotates rapidly so that the second driving plate moves into the second limiting space.

[0009] The present invention is further configured as follows: the second limiting plate includes a plate body and a reset member, the moving contact is provided with a sliding groove, the plate body is provided with an extension arm extending into the sliding groove, the reset member is arranged in the sliding groove and abuts against the extension arm to push the plate body to move in the direction of the cam.

[0010] The present invention is further configured as follows: the limit block is telescopically connected to the cam, and a control member for controlling the telescopic movement of the limit block is provided on the housing.

[0011] The present invention is further configured as follows: the control component includes a control rod and a control spring, the control rod is slidably connected to the shell through the control spring, a push spring is arranged in the cam, the push spring is used to push the limit block to extend, and a push portion is arranged on the limit block. When the control rod moves toward the limit block, the limit block is retracted into the cam through the push portion.

[0012] The present invention is further configured as follows: the push portion includes a push groove arranged on the limit block, and the push groove is provided with a push inclined surface.

[0013] The present invention is further configured such that: the reset element includes a reset rubber.

[0014] The present invention is further configured as follows: the moving contact and the housing are both correspondingly provided with through slots for the control rod to pass through.

[0015] In summary, the present invention has the following beneficial effects: When the moving contact has poor contact with the static contact or the current is too large due to an unexpected situation, causing the temperature to rise in the area of the moving contact, the compensation mechanism can perform position compensation operations or separation operations according to the temperature change range. This structure is independent of the tripping mechanism and can provide double insurance.

[0016] When the temperature of the moving contact rises, the expansion member in the expansion cavity will expand due to heat, thereby pushing the first drive plate towards the drive component, causing the drive component to rotate and the cam to rotate accordingly. The second drive plate moves along the increasing surface of the cam, thereby pushing the other side of the drive spring to keep the original spring force of the drive spring.

[0017] When the temperature of the moving contact continues to rise to an abnormal situation, the expansion member in the expansion cavity will continue to expand due to heat, further pushing the first drive plate towards the drive component. At this time, the second drive plate instantaneously moves downward along the decreasing surface of the cam, causing the static contact to separate from the moving contact and disconnecting the internal current. Description of the Drawings

[0018] Figure 1 It is a three-dimensional structure schematic diagram of a low-voltage circuit breaker; Figure 2 It is a three-dimensional structure schematic diagram inside the circuit breaker; Figure 3 It is for Figure 2 An enlarged schematic diagram at position A of Figure 4 It is a three-dimensional structure schematic diagram of the compensation mechanism; Figure 5 It is a three-dimensional structure schematic diagram of the drive component; Figure 6 It is a cross-sectional view of the position of the second drive plate.

[0019] Reference numerals: 1, housing; 11, through slot; 2, contact mechanism; 21, moving contact; 22, static contact; 23, expansion cavity; 24, operation cavity; 25, moving cavity; 3, operating mechanism; 4, compensation head; 5, compensation mechanism; 51, expansion member; 52, drive component; 521, cam; 522, drive gear; 523, connecting rod; 53, drive spring; 54, increasing surface; 55, decreasing surface; 56, sliding slot; 6, first drive plate; 61, sealing plate; 7, second drive plate; 71, plate body; 72, reset member; 8, limit block; 81, first limit space; 82, second limit space; 9, control member. Detailed Description of the Invention

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Referring to Figures 1 to 6 As shown, to achieve the above object, the present invention provides the following technical solution: A low-voltage circuit breaker includes a housing 1, a contact mechanism 2, and an operating mechanism 3. The contact mechanism 2 includes a moving contact 21 and a static contact 22 arranged oppositely. The operating mechanism 3 is used to drive the moving contact 21 to contact or separate from the static contact 22; A compensation head 4 and a compensation mechanism 5 are provided on the moving contact 21; An expansion cavity 23, an operating cavity 24, and a moving cavity 25 are sequentially arranged along the length direction inside the moving contact 21. The compensation head 4 is slidably connected inside the moving cavity 25. The compensation mechanism 5 includes an expansion member 51, a driving member 52, and a driving spring 53. The expansion member 51 is arranged inside the expansion cavity 23; The driving member 52 is arranged inside the operating cavity 24, and a first driving plate 6 and a second driving plate 7 which are linked with the driving member 52 are arranged inside the operating cavity 24. The driving spring 53 is arranged inside the moving cavity 25 and is respectively connected to the second driving plate 7 and the compensation head 4; One end of the first driving plate 6 is located inside the expansion cavity 23. When the moving contact 21 generates heat, the expansion member 51 pushes the first driving plate 6 to move towards the driving member 52; The driving member 52 at least includes a cam 521. An increasing surface 54 and a decreasing surface 55 are sequentially arranged along the rotation direction of the cam 521. The slope of the decreasing surface 55 is greater than that of the increasing surface 54. The second driving plate 7 is linked with the cam 521.

[0022] In the design of the present invention, when the operating mechanism 3 enables the moving contact 21 and the static contact 22 to be connected, the circuit is conducted.

[0023] First, through the design of the compensation head 4, the problem of insufficient abutment that the operating mechanism 3 may originally bring can be compensated.

[0024] When the moving contact 21 has a temperature rise in the area due to poor contact between the moving contact 21 and the static contact 22 or excessive current due to an accident, the compensation mechanism 5 can perform position compensation operation or separation operation according to the temperature change range. This structure is independent of the tripping mechanism and can provide double insurance.

[0025] When the temperature of the moving contact 21 rises, the expansion member 51 in the expansion chamber 23 will expand due to heat, thereby pushing the first drive plate 6 towards the drive member 52, causing the drive member 52 to rotate and the cam 521 to rotate accordingly. The second drive plate 7 moves along the increasing surface 54 of the cam 521, thereby pushing the other side of the drive spring 53, keeping the drive spring 53 with its original spring force.

[0026] When the temperature of the moving contact 21 continues to rise to an abnormal situation, the expansion member 51 in the expansion chamber 23 will continuously expand due to heat, further pushing the first drive plate 6 towards the drive member 52. At this time, the second drive plate 7 instantaneously moves downward along the decreasing surface 55 of the cam 521, causing the static contact 22 to separate from the moving contact 21 and disconnecting the internal current.

[0027] It should be noted that the initial position of the second drive plate 7 is on the increasing surface 54, so when it moves below the decreasing surface 55, its relative position is lower compared to the initial position.

[0028] The present invention is further configured such that: the drive member 52 further includes a drive gear 522 and a connecting rod 523. The drive gear 522 is connected to the cam 521 through the connecting rod 523, and one end of the first drive plate 6 is provided with an engaging structure that meshes with the drive gear 522.

[0029] As Figure 4 and Figure 5 shown, when the first drive plate 6 moves, it can drive the drive gear 522 to rotate counterclockwise through the engaging structure on the first drive plate 6. Under the action of the connecting rod 523, the cam 521 also rotates counterclockwise. When the vertical position of the second drive plate 7 remains unchanged, due to the existence of the increasing surface 54, the second drive plate 7 will gradually move towards the compensating head 4.

[0030] The compensating head 4 protrudes a little relative to the moving contact 21, which can improve the contact with the static contact 22.

[0031] The present invention is further configured such that: the expansion member 51 includes an expansion liquid. The first drive plate 6 includes a sealing plate 61 located in the expansion chamber 23. A sealing collar is provided on the periphery of the sealing plate 61, and the sealing plate 61 is slidably connected in the sealing chamber.

[0032] When the expansion liquid expands due to heat, the internal air pressure will increase. At this time, the pressure in the expansion chamber 23 is greater than the pressure in the operation chamber 24, thereby pushing the second drive plate 7 to move.

[0033] The present invention is further configured such that: a limiting block 8 is provided on the cam 521. The limiting block 8 is located on one side of the decreasing surface 55, and a first limiting space 81 is formed between the limiting block 8 and the decreasing surface 55. A second limiting space 82 is formed on the side of the limiting block 8 facing away from the decreasing surface 55; When the expansion member 51 is continuously and slowly heated, the second drive plate 7 moves along the decreasing surface 55 to the first limit space 81; When the expansion member 51 is rapidly heated, the cam 521 rotates rapidly, causing the second drive plate 7 to move into the second limit space 82.

[0034] The design of the limit block 8 divides the temperature rise situation into the following two cases when facing the temperature rise problem: 1. When heat dissipation is poor or the continuous current is too large due to environmental problems; 2. When the current is too large or a short circuit occurs due to unstable voltage, resulting in an excessive current problem; When the temperature of the moving contact 21 gradually rises due to poor heat dissipation, the expansion member 51 is continuously heated and expanded. At this time, the second drive plate 7 will move along the decreasing surface 55 into the second limit space 82. At this time, the moving contact 21 is separated from the static contact 22. When the temperature drops to the normal range, the second drive plate 7 can reset along the decreasing surface 55. If the operator monitors that the circuit breaker repeatedly interrupts the connection signal, the problem can be immediately determined.

[0035] When the second situation occurs, the instantaneous current is too large and the expansion member 51 is rapidly heated. At this time, the expansion speed of the expansion member 51 is relatively fast, causing the drive gear 522 to rotate rapidly, and then causing the limit block 8 to rotate rapidly beyond the position of the second drive plate 7, causing the second drive plate 7 to fall back into the second limit space 82. At this time, even if the temperature drops, the second drive plate 7 cannot reset.

[0036] The expansion member 51 can be optionally selected according to specific usage situations: expansion liquid, expansion gas, and expansion solid. Among them, the gas can be optionally sulfur hexafluoride (SF6) gas; The liquid can be optionally insulating oil; The solid can be optionally thermostatic bimetal material.

[0037] The above-mentioned sulfur hexafluoride (SF6) gas can be preferably selected according to the expansion speed.

[0038] The present invention is further configured as: the second limit plate includes a plate body 71 and a reset member 72. A sliding groove 56 is provided on the moving contact 21. An extension arm extending into the sliding groove 56 is provided on the plate body 71. The reset member 72 is disposed in the sliding groove 56 and abuts against the extension arm, and is used to push the plate body 71 toward the cam 521.

[0039] The reset member 72 includes a reset rubber.

[0040] In the case of selecting sulfur hexafluoride (SF6) gas, on the basis of being able to accelerate the rotation speed of the driving gear 522 when the instantaneous current is too large, the elastic potential energy of the reset member 72 is changed, and a rubber material with a slower rebound is selected to reduce the rebound speed of the second limiting plate, so as to strive for the rotation time required for the driving gear 522 to ensure the desired effect.

[0041] The present invention is further arranged as: the limiting block 8 is telescopically connected to the cam 521, and a control member 9 for controlling the telescopic movement of the limiting block 8 is arranged on the housing 1.

[0042] The present invention is further arranged as: the control member 9 includes a control rod and a control spring. The control rod is slidably connected to the inside of the housing 1 through the control spring. A pushing spring is arranged inside the cam 521, and the pushing spring is used to push the limiting block 8 to extend. A pushing portion is arranged on the limiting block 8. When the control rod moves towards the limiting block 8, the limiting block 8 retracts into the cam 521 through the pushing portion.

[0043] The present invention is further arranged as: the pushing portion includes a pushing groove arranged on the limiting block 8, and a pushing inclined surface is arranged on the pushing groove.

[0044] The present invention is further arranged as: through grooves 11 for the control rod to pass through are correspondingly arranged on both the moving contact 21 and the housing 1.

[0045] For the design of this structure, for example, after the short - circuit situation is checked, the operator can use a needle - shaped device to poke the control rod, so that the control rod pushes the pushing inclined surface. As the control rod continuously penetrates, the limiting block 8 moves back into the cam 521. At this time, when the expansion member 51 in the expansion cavity 23 retracts, the pressure in the expansion cavity 23 is less than the pressure in the operation cavity 24, and the first driving plate 6 controls the driving gear 522 to rotate back, so that the second driving plate 7 and the compensation head 4 extend towards the static contact 22.

[0046] Therefore, this device can be used multiple times and repeatedly.

[0047] The above is only the preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above - mentioned embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A low-voltage circuit breaker, characterized in that: It comprises a housing, a contact mechanism and an operating mechanism, wherein the contact mechanism comprises a moving contact and a stationary contact arranged opposite to each other, and the operating mechanism is used to drive the moving contact to contact or separate with the stationary contact; The moving contact is provided with a compensation head and a compensation mechanism; The moving contact is provided with an expansion chamber, an operation chamber and a moving chamber in sequence along its length direction, the compensation head is slidably connected in the moving chamber, the compensation mechanism includes an expansion member, a driving member and a driving spring, and the expansion member is provided in the expansion chamber; The driving component is arranged in the operating chamber, and the operating chamber is provided with a first driving plate and a second driving plate which are arranged in linkage with the driving component, and the driving spring is arranged in the moving chamber and is connected with the second driving plate and the compensation head respectively; One end of the first driving plate is located in the expansion cavity, and when the moving contact is heated, the expansion member pushes the first driving plate to move toward the driving component; The driving component at least includes a cam, and the cam is provided with an increasing surface and a decreasing surface in sequence along its rotation direction. The slope of the decreasing surface is greater than the slope of the increasing surface. The second driving plate is arranged in linkage with the cam.

2. A low-voltage circuit breaker according to claim 1, characterized in that: The driving component also includes a driving gear and a connecting rod. The driving gear is connected to the cam through the connecting rod. One end of the first driving plate is provided with an engaging structure engaged with the driving gear.

3. A low-voltage circuit breaker according to claim 2, characterized in that: The expansion member includes an expansion fluid, the first driving plate includes a sealing plate located in the expansion cavity, a sealing ring is arranged on the peripheral side of the sealing plate, and the sealing plate is slidably connected in the sealing cavity.

4. A low-voltage circuit breaker according to claim 1, characterized in that: A limiting block is arranged on the cam, the limiting block is located on one side of the decreasing surface, a first limiting space is formed between the limiting block and the decreasing surface, and a second limiting space is formed on the side of the limiting block away from the decreasing surface; When the expansion member continues to slowly heat up, the second driving plate moves along the decreasing surface to the first limiting space; When the expansion member heats up rapidly, the cam rotates rapidly so that the second driving plate moves into the second limiting space.

5. A low-voltage circuit breaker according to claim 4, characterized in that: The second limit plate includes a plate body and a reset member, the moving contact is provided with a sliding groove, the plate body is provided with an extension arm extending into the sliding groove, the reset member is arranged in the sliding groove and abuts against the extension arm to push the plate body to move in the direction of the cam.

6. A low-voltage circuit breaker according to claim 4, characterized in that: The limit block is telescopically connected to the cam, and a control member for controlling the telescopic movement of the limit block is provided on the housing.

7. A low-voltage circuit breaker according to claim 6, characterized in that: The control component includes a control rod and a control spring. The control rod is slidably connected to the shell through the control spring. A push spring is arranged in the cam. The push spring is used to push the limit block to extend. The limit block is provided with a push portion. When the control rod moves toward the limit block, the limit block is retracted into the cam through the push portion.

8. A low-voltage circuit breaker according to claim 7, characterized in that: The push portion includes a push groove arranged on the limit block, and the push groove is provided with a push inclined surface.

9. A low-voltage circuit breaker according to claim 5, characterized in that: The reset element includes a reset rubber.

10. A low-voltage circuit breaker according to claim 7, characterized in that: The moving contact and the housing are both correspondingly provided with through slots for the control rod to pass through.

Images