Breaker thermal release

Abstract

The invention belongs to the technical field of low-voltage electric appliances, and discloses a circuit breaker thermal tripper, a circuit breaker comprises a base, a cover body, a moving contact assembly, a transmission mechanism and a thermal tripper, the base and the cover body are combined to form a containing cavity, the moving contact assembly, the transmission mechanism and the thermal tripper are arranged in the containing cavity, and the thermal tripper is arranged in the containing cavity. The thermal release comprises a traction rod, a thermal adjustable push rod, a bimetallic strip and an axial driving assembly. According to the thermal tripper of the circuit breaker, the sensitivity of the thermal tripper to different temperatures can be adjusted in a large range by adjusting the initial distance and the contact position between the delay screw on the bimetallic strip and the second transmission part on the thermal adjustable push rod, so that the protection action can be triggered under a proper temperature condition according to specific application scenes and requirements, and the safety of the circuit breaker is ensured. Therefore, different load characteristics and protection requirements are met, and safe operation of circuits and equipment is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of low-voltage electrical appliances, and in particular to a thermal release of a circuit breaker. Background Art

[0002] Circuit breakers play a great role in the transmission and distribution of electricity and the protection of motors. They are widely used products in low-voltage electrical appliances. Circuit breakers are mainly composed of contact arc extinguishing system, transmission mechanism and release. The release is an important mechanism in the circuit breaker. The function of the release is to convert electrical energy into mechanical action. When receiving the trip signal, the circuit breaker is opened to realize the protection of the circuit breaker against overload or short circuit faults.

[0003] Common trip devices are divided into two types: electronic and thermal-magnetic. Electronic trip devices perform well in providing high-precision and adjustable protection functions, but the cost is relatively high. Thermal-magnetic trip devices have low costs and stable performance, but the protection functions are relatively simple, and they only provide magnetic protection (short-circuit protection) and thermal protection (overload protection). Thermal trip devices, in particular, have large action value errors, unadjustable thermal sensitivity or limited adjustment capabilities, and are greatly affected by the environment, which in turn affects the comprehensiveness and reliability of the protection functions of the trip devices. Summary of the invention

[0004] Based on the above problems, the object of the present invention is to provide a thermal release of a circuit breaker, optimize the internal structure of the release, and realize a wider range of thermal adjustable functions.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A circuit breaker thermal release, the circuit breaker comprises a base, a cover, a moving contact assembly, a transmission mechanism and a thermal release, the base and the cover are combined to form a cavity, the moving contact assembly, the transmission mechanism and the thermal release are arranged in the cavity, the thermal release comprises a traction rod, a thermally adjustable push rod, a bimetallic sheet and an axial drive assembly, wherein:

[0007] The traction rod is used to drive the transmission mechanism to realize the tripping function of the circuit breaker;

[0008] The thermally adjustable push rod is provided with a first transmission part, a second transmission part and a third transmission part, the first transmission part is used to drive the traction rod to rotate, and the second transmission part is provided with a contact surface with a height change along the axial direction of the thermally adjustable push rod;

[0009] The bimetallic strip is located on one side of the thermally adjustable push rod and is electrically connected to the moving contact assembly. The bimetallic strip bends toward the thermally adjustable push rod after being heated. A delay screw is provided on the bimetallic strip. The delay screw is used to press the contact surface after the bimetallic strip is bent, thereby driving the thermally adjustable push rod to rotate. The distance between the delay screw and the contact surface before the bimetallic strip is bent is adjustable.

[0010] The axial drive assembly acts on the third transmission part to drive the thermally adjustable push rod to move axially, thereby changing the position of the delay screw pressing on the contact surface.

[0011] As an optional solution, the axial drive assembly includes a fixed bracket, a slider and a knob, wherein:

[0012] The fixing bracket is fixed on the cover body;

[0013] The slider is slidably arranged on the fixed bracket, and the sliding direction of the slider is the same as the axial direction of the thermally adjustable push rod;

[0014] The knob is rotatably arranged on the fixed bracket, and an eccentric column is arranged at the lower end of the knob;

[0015] The third transmission part is provided with a first limiting groove perpendicular to the axial direction of the thermally adjustable push rod;

[0016] One end of the slider is provided with a linkage rod inserted into the first limiting groove, and the other end of the slider is provided with a second limiting groove for the eccentric column to be inserted.

[0017] As an optional solution, a protrusion is provided on the outer edge of the knob, and a stopper is provided on the fixed bracket. The two stops limit the travel on both sides of the protrusion, thereby limiting the rotation angle of the knob.

[0018] As an optional solution, the surface of the fixed bracket in contact with the knob is provided with a plurality of gear grooves distributed around the circumference of the knob, and the surface of the knob in contact with the fixed bracket is provided with convex points, which can slide in and out of each gear groove.

[0019] As an optional solution, the upper end of the knob is exposed from the cover body, and an arrow groove is provided on the upper end surface of the knob, the arrow groove is used to display the current angle of the knob and for inserting a screwdriver to drive the knob to rotate.

[0020] As an optional solution, a concave cavity for installing the slider is provided on the fixed bracket, convex ridges arranged along the sliding direction of the slider are provided on the side wall of the concave cavity, and a sliding groove cooperating with the convex ridges is provided on the slider.

[0021] As an optional solution, a return torsion spring is sleeved on the thermally adjustable push rod, one end of the return torsion spring abuts against the base, and the other end of the return torsion spring abuts against the second transmission part.

[0022] As an optional solution, a right-angle portion is provided on the third transmission portion and on one side of the thermally adjustable push rod. When the right-angle portion abuts against the base, the rotation of the thermally adjustable push rod under the action of the return torsion spring is restricted.

[0023] As an optional solution, the second transmission part includes a high potential area, a low potential area and a slope area connecting the high potential area and the low potential area, and the contact surface is the upper surface of the high potential area, the upper surface of the slope area and the upper surface of the low potential area.

[0024] As an optional solution, a fixing nut is provided on the bimetallic strip, and the delay screw is threadedly connected to the fixing nut.

[0025] The beneficial effects of the present invention are as follows: the thermal release of the circuit breaker can adjust the sensitivity of the thermal release to different temperatures over a wide range by adjusting the initial distance and contact position between the delay screw on the bimetallic strip and the second transmission part on the thermally adjustable push rod, thereby ensuring that the protection action is triggered under appropriate temperature conditions according to specific application scenarios and requirements, so as to adapt to different load characteristics and protection requirements and ensure the safe operation of circuits and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a structural appearance diagram of a circuit breaker provided by an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the circuit breaker in the closed state according to the embodiment of the present invention Figure 1 ;

[0028] Figure 3 Schematic diagram of the circuit breaker in the closed state according to the embodiment of the present invention Figure 2 ;

[0029] Figure 4 is a structural schematic diagram of a tripping state of a circuit breaker provided by an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of a thermal release device of a circuit breaker provided in an embodiment of the present invention Figure 1 ;

[0031] Figure 6 Schematic diagram of a thermal release device of a circuit breaker provided in an embodiment of the present invention Figure 2 ;

[0032] Figure 7 It is a schematic structural diagram of a knob in a thermal release of a circuit breaker provided in an embodiment of the present invention;

[0033] Figure 8 It is a structural schematic diagram of a slider in a thermal release of a circuit breaker provided in an embodiment of the present invention;

[0034] Fig. 9 The invention is a schematic structural diagram of a thermally adjustable push rod in a thermal release of a circuit breaker provided in an embodiment of the present invention.

[0035] In the attached figure:

[0036] 1. Traction bar;

[0037] 2. Thermally adjustable push rod; 21. First transmission part; 22. Second transmission part; 221. High potential area; 222. Low potential area; 223. Slope area; 23. Third transmission part; 231. First limiting groove; 232. Right angle part; 24. Reset torsion spring;

[0038] 3. Bimetallic strip; 31. Delay screw; 32. Fixing nut;

[0039] 4. Axial drive assembly; 41. Fixed bracket; 411. Stopper; 412. Stopper groove; 413. Protruding ridge; 42. Sliding block; 421. Linking rod; 422. Second limiting groove; 423. Sliding groove; 43. Knob; 431. Eccentric column; 432. Protruding block; 433. Protruding point; 434. Arrow groove;

[0040] 5. Base;

[0041] 6. Cover body;

[0042] 7. Moving contact assembly;

[0043] 8. Transmission mechanism; 81. Auxiliary lock. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0045] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0047] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0048] See also Figures 1 to 4 As shown, this preferred embodiment provides a circuit breaker thermal release, wherein the circuit breaker comprises a base 5, a cover 6, a moving contact assembly 7, a transmission mechanism 8 and a thermal release, the base 5 and the cover 6 are combined to form a cavity, and the moving contact assembly 7, the transmission mechanism 8 and the thermal release are arranged in the cavity. Whether it is an electronic circuit breaker or a thermal magnetic circuit breaker, the base 5 and the cover 6 here can be universal.

[0049] In particular, the thermal release here includes a traction rod 1, a thermally adjustable push rod 2, a bimetallic strip 3 and an axial drive assembly 4, see Figure 5 ,in:

[0050] The traction rod 1 is used to drive the transmission mechanism 8 to operate and realize the tripping function of the circuit breaker;

[0051] The thermally adjustable push rod 2 is provided with a first transmission part 21, a second transmission part 22 and a third transmission part 23, the first transmission part 21 is used to drive the traction rod 1 to rotate, and the second transmission part 22 is provided with a contact surface that changes along the axial height of the thermally adjustable push rod 2;

[0052] The bimetallic strip 3 is located on one side of the thermally adjustable push rod 2 and is electrically connected to the moving contact assembly 7. The bimetallic strip 3 bends toward the thermally adjustable push rod 2 after being heated. A delay screw 31 is provided on the bimetallic strip 3. The delay screw 31 is used to press the contact surface of the second transmission part 22 after the bimetallic strip 3 is bent, thereby driving the thermally adjustable push rod 2 to rotate. The distance from the delay screw 31 to the contact surface before the bimetallic strip 3 is bent is adjustable.

[0053] The axial drive assembly 4 acts on the third transmission part 23 to drive the thermally adjustable push rod 2 to move axially, thereby changing the position of the delay screw 31 pressing on the contact surface.

[0054] Therefore, by adjusting the initial distance and contact position between the delay screw 31 on the bimetallic strip 3 and the second transmission part 22 on the thermally adjustable push rod 2, the sensitivity of the thermal release to different temperatures can be adjusted over a wide range, thereby ensuring that the protection action is triggered under appropriate temperature conditions according to specific application scenarios and requirements, so as to adapt to different load characteristics and protection requirements, thereby ensuring the safe operation of circuits and equipment.

[0055] Specifically, the axial drive assembly 4 can be implemented in a variety of forms, as long as it can simply drive the thermally adjustable push rod 2 to move axially. This embodiment is exemplified by the following form, which includes a fixed bracket 41, a slider 42 and a knob 43, see Figures 5 to 9 ,in:

[0056] The fixing bracket 41 is fixed on the cover body 6;

[0057] The slider 42 is slidably disposed on the fixed bracket 41, and the sliding direction of the slider 42 is the same as the axial direction of the thermally adjustable push rod 2;

[0058] The knob 43 is rotatably disposed on the fixed bracket 41, and an eccentric column 431 is disposed at the lower end of the knob 43;

[0059] The third transmission part 23 is provided with a first limiting groove 231 which is perpendicular to the axial direction of the thermally adjustable push rod 2;

[0060] A linkage rod 421 inserted into the first limiting groove 231 is disposed at one end of the slider 42 , and a second limiting groove 422 for the eccentric column 431 to be inserted is disposed at the other end of the slider 42 .

[0061] Therefore, through the cooperation between the eccentric column 431 and the second limiting groove 422, the rotation of the knob 43 is converted into the sliding of the slider 42, and through the cooperation between the linkage rod 421 and the first limiting groove 231, the sliding of the slider 42 is converted into the axial movement of the thermally adjustable push rod 2, thereby changing the relative position of the delay screw 31 and the second transmission part 22 through the knob 43, thereby achieving the effect of adjustable thermal release.

[0062] Optionally, see Figure 6 A protrusion 432 is provided on the outer edge of the knob 43, and a stopper 411 is provided on the fixed bracket 41. The two stops 411 limit the travel on both sides of the protrusion 432, thereby limiting the rotation angle of the knob 43 to ensure that the adjustment action is carried out normally within the set range.

[0063] Optionally, the knob 43 has several gears during the rotation process. This embodiment takes three gears as an example. Figure 6 and Figure 7 The surface of the fixed bracket 41 that contacts the knob 43 is provided with three gear grooves 412 distributed around the circumference of the knob 43, and the surface of the knob 43 that contacts the fixed bracket 41 is provided with a convex point 433, which can slide in and out of each gear groove 412, so that the gear switching can be clearly felt during the process of turning the knob 43.

[0064] Furthermore, the upper end of the knob 43 is exposed from the cover body 6, and an arrow groove 434 is provided on the upper end face of the knob 43, the arrow groove 434 is used to display the current angle of the knob 43, and to allow a screwdriver to be inserted to drive the knob 43 to rotate, thereby facilitating the operation of rotating the knob 43 to the target gear position.

[0065] Optionally, a concave cavity for installing the slider 42 is provided on the fixed bracket 41, and a convex ridge 413 arranged along the sliding direction of the slider 42 is provided on the side wall of the concave cavity. A sliding groove 423 cooperating with the convex ridge 413 is provided on the slider 42, thereby ensuring that the slider 42 slides back and forth accurately on the fixed bracket 41.

[0066] Optionally, a reset torsion spring 24 is sleeved on the thermally adjustable push rod 2, one end of the reset torsion spring 24 abuts against the base 5, and the other end of the reset torsion spring 24 abuts against the second transmission part 22, so that the thermally adjustable push rod 2 can automatically reset when not affected by the delay screw 31.

[0067] Furthermore, a right angle portion 232 is provided on the third transmission portion 23 and on one side of the heat-adjustable push rod 2, see Figure 5 When the right-angle portion 232 abuts against the base 5, the rotation of the thermally adjustable push rod 2 under the action of the reset torsion spring 24 is restricted, thereby preventing the thermally adjustable push rod 2 from rotating excessively when resetting.

[0068] Optionally, see Fig. 9 The second transmission part 22 includes a high potential area 221, a low potential area 222 and a slope area 223 connecting the high potential area 221 and the low potential area 222. The contact surfaces are the upper surface of the high potential area 221, the upper surface of the slope area 223 and the upper surface of the low potential area 222. When the heat-adjustable push rod 2 moves axially, the delay screw 31 abuts against the high potential area 221 or the low potential area 222 or a certain position on the low potential area 222. Due to the different heights of the high potential area 221, the low potential area 222 and the slope area 223, the relative distance between the delay screw 31 and the second transmission part 22 changes, which means that the delay screw 31 can only touch the second transmission part 22 when the bimetallic strip 3 has different bending degrees (i.e. different temperatures), so that the protection action can be triggered under the desired temperature conditions.

[0069] Specifically, a fixing nut 32 is provided on the bimetallic strip 3, and the delay screw 31 is threadedly connected to the fixing nut 32, so that the initial distance between the delay screw 31 and the second transmission part 22 is adjustable, that is, the thermal release is allowed to trigger the protection action after a certain time delay after reaching a certain temperature, so that it can better adapt to different load characteristics and protection requirements, and avoid false operation or premature operation.

[0070] Specific installation structure:

[0071] The bimetallic strip 3 is fastened to the moving contact assembly 7 by screws, and the moving contact assembly 7 and the outlet terminal connecting plate are fastened with screws and uniformly installed on the base 5; the delay screw 31 and the fixing nut 32 are assembled and installed on the bimetallic strip 3; the reset torsion spring 24 is installed into the thermally adjustable push rod 2, and the rear installation part of the push rod is assembled, and then the thermally adjustable push rod 2 is installed on the base 5, the base 5 and the cover body 6 are assembled and combined, the transmission mechanism 8 is fixed on the base 5 and the cover body 6, and the fixed bracket 41 is combined with the slider 42 and the knob 43 and fastened to the cover body 6.

[0072] Insert a flat-blade screwdriver into the arrow groove 434 to drive the knob 43 to rotate, and the protrusion 432 of the knob 43 and the two blocks 411 of the fixed bracket 41 cooperate to limit, so that the slider 42 is linked with the eccentric column 431 of the knob 43 and the second limiting groove 422 of the slider 42 and the convex ridge 413 of the fixed bracket 41 and the groove of the slider 42, so that the thermally adjustable push rod 2 is translated left and right under the cooperation of the linkage rod 421 of the slider 42 and the first limiting groove 231 on the third transmission part 23 of the thermally adjustable push rod 2, thereby changing the relative position of the contact surface between the delay screw 31 and the second transmission part 22 of the thermally adjustable push rod 2.

[0073] When the circuit breaker carries an overloaded operating current (for example, 2 times), the entire conductive part connecting plate will generate a lot of heat, the bimetallic strip 3 will bend due to the heat, and the delay screw 31 will push the second transmission part 22 of the thermally adjustable push rod 2 to rotate the thermally adjustable push rod 2. The first transmission part 21 of the thermally adjustable push rod 2 will rotate in conjunction with the traction rod 1, so that the part of the traction rod 1 that locks the secondary lock 81 will be unlocked, so that the entire transmission mechanism 8 will be tripped. For details, see Figure 3 and Figure 4 .

[0074] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A circuit breaker thermal release, the circuit breaker comprising a base (5), a cover (6), a moving contact assembly (7), a transmission mechanism (8) and a thermal release, the base (5) and the cover (6) being combined to form a cavity, the moving contact assembly (7), the transmission mechanism (8) and the thermal release being arranged in the cavity, characterized in that: The thermal release comprises a traction rod (1), a thermally adjustable push rod (2), a bimetallic strip (3) and an axial drive assembly (4), wherein: The traction rod (1) is used to drive the transmission mechanism (8) to operate, thereby realizing the tripping function of the circuit breaker; The thermally adjustable push rod (2) is provided with a first transmission part (21), a second transmission part (22) and a third transmission part (23), the first transmission part (21) being used to drive the traction rod (1) to rotate, and the second transmission part (22) is provided with a contact surface whose height varies along the axial direction of the thermally adjustable push rod (2); The bimetallic strip (3) is located on one side of the thermally adjustable push rod (2) and is electrically connected to the moving contact assembly (7); the bimetallic strip (3) bends toward the thermally adjustable push rod (2) after being heated; a delay screw (31) is provided on the bimetallic strip (3); the delay screw (31) is used to press the contact surface after the bimetallic strip (3) is bent, thereby driving the thermally adjustable push rod (2) to rotate; the distance between the delay screw (31) and the contact surface before the bimetallic strip (3) is bent is adjustable; The axial drive assembly (4) acts on the third transmission part (23) to drive the thermally adjustable push rod (2) to move axially, thereby changing the position of the delay screw (31) pressing on the contact surface.

2. The circuit breaker thermal release according to claim 1, characterized in that: The axial drive assembly (4) comprises a fixed bracket (41), a slider (42) and a knob (43), wherein: The fixing bracket (41) is fixed on the cover body (6); The sliding block (42) is slidably disposed on the fixed bracket (41), and the sliding direction of the sliding block (42) is the same as the axial direction of the thermally adjustable push rod (2); The knob (43) is rotatably mounted on the fixed bracket (41), and an eccentric column (431) is disposed at the lower end of the knob (43); The third transmission part (23) is provided with a first limiting groove (231) which is perpendicular to the axial direction of the thermally adjustable push rod (2); One end of the slider (42) is provided with a linkage rod (421) inserted into the first limiting groove (231), and the other end of the slider (42) is provided with a second limiting groove (422) for the eccentric column (431) to be inserted.

3. The circuit breaker thermal release according to claim 2, characterized in that: The outer edge of the knob (43) is provided with a protrusion (432), and the fixing bracket (41) is provided with a stopper (411), and the two stoppers (411) limit the travel of both sides of the protrusion (432), thereby limiting the rotation angle of the knob (43).

4. The circuit breaker thermal release according to claim 3, characterized in that: A plurality of shift grooves (412) distributed around the circumference of the knob (43) are provided on the surface of the fixed bracket (41) in contact with the knob (43), and a convex point (433) is provided on the surface of the knob (43) in contact with the fixed bracket (41), and the convex point (433) can slide in and out of each of the shift grooves (412).

5. The circuit breaker thermal release according to claim 4, characterized in that: The upper end of the knob (43) is exposed from the cover body (6), and an arrow groove (434) is provided on the upper end surface of the knob (43), wherein the arrow groove (434) is used to display the current angle of the knob (43) and to allow a screwdriver to be inserted to drive the knob (43) to rotate.

6. The circuit breaker thermal release according to claim 2, characterized in that: The fixing bracket (41) is provided with a concave cavity for mounting the slider (42), the side wall of the concave cavity is provided with ridges (413) arranged along the sliding direction of the slider (42), and the slider (42) is provided with a sliding groove (423) cooperating with the ridges (413).

7. The circuit breaker thermal release according to claim 1, characterized in that: The heat-adjustable push rod (2) is sleeved with a return torsion spring (24), one end of the return torsion spring (24) abuts against the base (5), and the other end of the return torsion spring (24) abuts against the second transmission part (22).

8. The circuit breaker thermal release according to claim 7, characterized in that: A right-angle portion (232) is provided on the third transmission portion (23) and located on one side of the thermally adjustable push rod (2); when the right-angle portion (232) abuts against the base (5), the rotation of the thermally adjustable push rod (2) under the action of the return torsion spring (24) is restricted.

9. The circuit breaker thermal release according to claim 1, characterized in that: The second transmission part (22) comprises a high potential area (221), a low potential area (222) and a slope area (223) connecting the high potential area (221) and the low potential area (222), and the contact surface is the upper surface of the high potential area (221), the upper surface of the slope area (223) and the upper surface of the low potential area (222).

10. The circuit breaker thermal release according to claim 1, characterized in that: The bimetallic strip (3) is provided with a fixing nut (32), and the delay screw (31) is threadedly connected to the fixing nut (32).

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