Thermal electromagnetic release

Abstract

A thermal electromagnetic release comprises a bracket, and a coil assembly and a heating assembly respectively mounted on the bracket, wherein the heating assembly comprises a heating element and a bimetallic strip, wherein the heating element is electrically connected to the coil assembly, and the bimetallic strip is connected in parallel with the heating element via a conductive member. On the basis of the series connection of the coil assembly and the heating element, the bimetallic strip is further connected in parallel with the heating element via a conductive member, which not only shunts the current between the heating element and the bimetallic strip, thus preventing the bimetallic strip from fusing, but also enables the bimetallic strip to be heated by the heating element while self-heating. Even if the rated current is small, the problem of inconsistent delayed action due to the small heat generation will not occur.

Description

Technical Field

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

[0002] The thermal electromagnetic release is a key actuator of a circuit breaker. Its bimetallic strip bends when the temperature changes. For example, when the circuit is overloaded and the temperature rises, the bending of the bimetallic strip triggers the circuit breaker to trip. Bimetallic strips are generally classified by their operating principles as direct heating and indirect heating. The direct heating type allows current to pass through the bimetallic strip, directly heating it and causing it to bend. However, it can only be used in circuit breakers with lower rated currents, as otherwise it could easily cause the bimetallic strip to melt. Indirect heating, the current does not pass through the bimetallic strip, but instead passes through another heating element, which heats the bimetallic strip. Although this type is more widely used, the heating element generates less heat, resulting in inconsistent delay action. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a thermo-electromagnetic release with both direct heating and indirect heating.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions:

[0005] A thermal electromagnetic release comprises a bracket and a coil assembly and a heating assembly respectively mounted on the bracket. The heating assembly comprises a heating element and a bimetallic strip. The heating element is electrically connected to the coil assembly, and the bimetallic strip is connected in parallel with the heating element via a conductive member.

[0006] Preferably, the bimetallic strip comprises at least two bimetallic strips spaced apart from each other, one end of the at least two bimetallic strips being connected together via a bimetallic connecting piece, and the other ends of the at least two bimetallic strips being fixed to the heating element via conductive members.

[0007] Preferably, the bimetallic strip is integrally formed into a U-shaped structure, a slot is provided in the middle of the bimetallic strip, the bimetallic strip includes two bimetallic strips arranged opposite to each other on both sides of the slot, and a bimetallic connecting piece connected between one ends of the two bimetallic strips, and the other ends of the two bimetallic strips are respectively fixed to the heating element through conductive parts.

[0008] Preferably, the heating element includes a heating part and a fixed part, the heating part and the bimetallic strip are respectively U-shaped structures, the two ends of the heating part and the bimetallic strip are respectively connected, the heating part and the other parts of the bimetallic strip are spaced apart, one end of the heating part is connected to the fixed part, and the other end of the heating part is spaced apart from the fixed part.

[0009] Preferably, the heating part is provided with a second slot, and the heating part includes two heating strips arranged on both sides of the second slot relative to each other, and a heating plate connected between one ends of the two heating strips, wherein the other end of one heating strip is respectively connected to one end of the bimetallic strip and the fixed part, and the other end of the other heating strip is connected to one end of the bimetallic strip and is spaced apart from the fixed part, and the ends of the two heating strips connected to the heating plate are respectively bent toward the side away from the bimetallic strip, forming a spacing groove between the heating element and the bimetallic strip.

[0010] Preferably, it also includes an armature rotatably mounted on the bracket, the coil assembly includes an insulating assembly and a wire group arranged in the insulating assembly, an iron core is provided on the inner side of the wire group, one end of the wire group is connected to the connecting plate, and the other end is connected to the part where the heating element and the bimetallic strip are spaced apart through a flexible connection.

[0011] Preferably, the bracket includes a left plate and a right plate that are arranged opposite to each other, and a left yoke and a right yoke are fixedly installed on the inner sides of the left plate and the right plate respectively, and the left yoke and the right yoke are arranged opposite to each other on both sides of the coil assembly.

[0012] Preferably, a heat shrink tube is provided on the inner side of the wire group and is included on the iron core.

[0013] Preferably, protrusions are respectively provided on both sides of the armature, and grooves with U-shaped structures are respectively provided on the top sides of the left plate and the right plate. The protrusions can be inserted into the corresponding grooves of the left plate and the right plate and rotated respectively. The left plate and the right plate are respectively provided with limiting parts for limiting the armature on the sides close to the armature.

[0014] Preferably, the iron core and / or the heating element are respectively provided with a boss structure, and the left yoke and the right yoke are respectively provided with a through-hole structure corresponding to the boss structure, and the boss structure passes through the corresponding through-hole structure and is fixed by riveting.

[0015] Preferably, the left yoke and the right yoke are respectively provided with a boss structure, and the left plate and the right plate are respectively provided with a through-hole structure corresponding to the boss structure, and the boss structure passes through the corresponding through-hole structure and is fixed by riveting.

[0016] The thermal electromagnetic release created by the present invention connects the coil assembly and the heating element in series, and connects the bimetallic strip in parallel with the heating element through a conductive member. This not only shunts the current between the heating element and the bimetallic strip, thus preventing the bimetallic strip from fusing, but also allows the bimetallic strip to be heated by the heating element while self-heating. Even if the rated current is small, the problem of inconsistent delayed action due to the small heat generation will not occur.

[0017] In addition, by providing a slot in the middle of the bimetallic strip, the bimetallic strip is made into a U-shaped structure, and the current is diverted through two bimetallic strips, which can prevent the bimetallic strip from being burned by a large current. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a thermal electromagnetic release device created by the present invention;

[0019] Figure 2 This is a left side view of the thermal electromagnetic release device created by the present invention;

[0020] Figure 3 This is an exploded top view of the thermal electromagnetic release created by the present invention;

[0021] Figure 4 This is an exploded view of the thermal electromagnetic release created by the present invention;

[0022] Figure 5 This invention Figure 4 A partial enlarged view of

[0023] Figure 6 This is a schematic diagram of the coordination between the bimetallic strip and the heating element created by the present invention;

[0024] Figure 7 This is a schematic diagram of the current flow on one side of the bimetallic strip and the heating element created by the present invention;

[0025] Figure 8 It is a schematic diagram of the current flow between the bimetallic strip and the other side of the heating element created by the present invention. DETAILED DESCRIPTION

[0026] The following is combined with Figures 1 to 6 The following examples further illustrate the specific implementation of the thermal electromagnetic release device created by the present invention. The thermal electromagnetic release device created by the present invention is not limited to the description of the following examples.

[0027] like Figure 1-6 As shown, the thermal electromagnetic release device of the present invention includes a bracket, a coil assembly, and a heating assembly mounted on the bracket. The heating assembly includes a heating element 11 and a bimetallic strip 13. The heating element 11 is electrically connected to the coil assembly via a flexible connector 16, and the bimetallic strip 13 is connected in parallel with the heating element 11 via a conductive member 12. In this embodiment, the side of the heating element 11 away from the bimetallic strip 13 is connected to the coil assembly via a flexible connector 16, and the bimetallic strip 13 is fixed to the other side of the heating element 11 via a conductive member 12.

[0028] The thermal electromagnetic release created by the present invention is based on the fact that the coil assembly and the heating element 11 are connected in series through the flexible connection 16, and the bimetallic strip 13 is connected in parallel with the heating element 11 through the conductive member 12. This not only shunts the current between the heating element 11 and the bimetallic strip 13, thus preventing the bimetallic strip 13 from fusing, but also allows the bimetallic strip 13 to be heated by the heating element 11 while self-heating. Even if the rated current is small, the problem of inconsistent delayed action due to the small heat generation will not occur.

[0029] like Figure 5-6 As shown, the bimetallic strip includes at least two spaced-apart bimetallic strips 132, one end of the at least two bimetallic strips 132 being connected together by a bimetallic connecting piece 133, and the other ends of the at least two bimetallic strips 132 being fixed to the heating element 11 via a conductive member 12. The bimetallic strip 13 of this embodiment is integrally formed into a U-shaped structure, with a slot 131 provided in the middle of the bimetallic strip 13. The bimetallic strip 13 includes two bimetallic strips 132 oppositely disposed on opposite sides of the slot 131, and a bimetallic connecting piece 133 connected between one end of the two bimetallic strips 132. The other ends of the two bimetallic strips 132 are fixed to the heating element 11 via a conductive member 12. An adjustment screw 14 is provided on the bimetallic connecting piece 133. When the bimetallic strip 13 bends, the adjustment screw 14 drives the adjustment screw 14 to trigger the operating mechanism of the circuit breaker, causing the operating mechanism to trip the circuit breaker. Adjusting the length of the adjustment screw 14 can adjust the delay characteristics. In this embodiment, a slot 131 is provided in the middle of the bimetallic strip 13 to give the bimetallic strip 13 a U-shaped structure. Current is divided by two bimetallic strips 132 to prevent the bimetallic strip 13 from being burned by a large current.

[0030] Preferably, the conductive member 12 is a rivet. The conductive member 12 may also be other parts without specific limitation. It is understood that the bimetallic strip includes at least two bimetallic strips 132 spaced apart from each other. The bimetallic strips 132 may be three or more. For example, the bimetallic strip 13 may be a W-shaped structure composed of three bimetallic strips 132. One end of at least two bimetallic strips 132 is connected together by a bimetallic connecting piece 133. The other ends of at least two bimetallic strips 132 are respectively fixed to the heating element 11 through the conductive member 12, which also has a shunting effect and falls within the scope of protection of the present invention.

[0031] like Figure 5-6 As shown, the heating element 11 includes a heating part and a fixing part, the heating part is in a U-shaped structure, the heating part and the bimetallic strip 13 are respectively in a U-shaped structure, the heating part and the two ends of the bimetallic strip 13 are respectively connected, the heating part and the other parts of the bimetallic strip 13 are spaced apart, one end of the heating part is connected to the fixing part, and the other end of the heating part is spaced apart from the fixing part.

[0032] The U-shaped structure of the heating part not only reduces the cross-sectional area and increases the heat output, but also enables it to work reliably at low ampere currents. Moreover, it matches the U-shaped structure of the bimetallic strip 13 and can be directly connected in parallel with the bimetallic strip 13 without taking up additional space, thus having the characteristic of being small in size.

[0033] Specifically, the heating element 11 includes a heating portion and a fixing portion, the fixing portion includes two fixing legs 114 relatively arranged on both sides of the heating portion, and fixing plates 115 respectively connected to the two fixing legs 114, the heating portion is a U-shaped structure corresponding to the bimetallic strip 13, a second slot 111 is provided in the middle of the heating portion, the heating portion includes two heating strips 112 relatively arranged on both sides of the second slot 111, and a heating plate 113 connected between one end of the two heating strips 112, the other end of one of the heating strips 112 is respectively connected to the bimetallic strip 13. One end of the sheet 13 is connected to the fixed plate 115, and the other end of the other heating strip 112 is connected to one end of the bimetallic strip 13 and is spaced apart from the fixed portion. The two bimetallic strips 132 of the bimetallic strip 13 are respectively fixed to the two heating strips 112 through the conductive member 12. The slot 131 of the bimetallic strip 13 corresponds to the second slot 111 on the heating portion. The ends of the two heating strips 112 connected to the heating sheet 113 are respectively bent away from the bimetallic strip 13, forming a spacing groove 110 between the heating element 11 and the bimetallic strip 13. The heating portion and the other parts of the bimetallic strip 13 are spaced apart, that is, the heating portion and the middle portion of the bimetallic strip 13 forming the spacing groove 110 are spaced apart.

[0034] like Figure 1-4 As shown, this embodiment also includes an armature 15 rotatably mounted on a bracket. The bracket includes a left side plate 8 and a right side plate 9 disposed opposite each other. A left yoke 6 and a right yoke 5 are fixedly mounted on the inner sides of the left side plate 8 and the right side plate 9, respectively. The left yoke 6 and the right yoke 5 are disposed opposite each other on either side of the coil assembly. The armature 15 is rotatably connected to the left side plate 8 and the right side plate 9, respectively. An upper hook 21 is provided on the armature 15, and a lower hook 20 is provided on the left yoke 6. A spring 10 is connected between the upper hook 21 and the lower hook 20 to drive the armature 15. Not only can the instantaneous actuation multiple of products with different amperages be met by adjusting the elastic force of the spring 10, but the left yoke 6 and the right yoke 5 can also ensure that the magnetic field of a low-amperage circuit breaker can be amplified during overload protection, thereby preventing the product from malfunctioning or failing to operate.

[0035] Preferably, the armature 15 is vertically arranged between the left side plate 8 and the right side plate 9, with protrusions 151 provided on both sides of the armature 15. The top sides of the left side plate 8 and the right side plate 9 are respectively provided with grooves 22 having a U-shaped structure. The protrusions 151 can be inserted into the corresponding grooves 22 of the left side plate 8 and the right side plate 9 and rotated. The left side plate 8 and the right side plate 9 are respectively provided with a limiting portion 23 for limiting the armature 15 on the side near the armature 15, so that the armature 15 is rotatably connected to the left side plate 8 and the right side plate 9, respectively. At the same time, the armature 15 is limited by the limiting portion 23 to prevent the armature 15 from falling off. The groove 22 of this embodiment has a U-shaped structure, which facilitates the insertion of the protrusions 151, can reduce the difficulty of assembling the armature 15, and the armature 15 is limited by the limiting portion 23, so that the armature 15 will not fall off during rotation.

[0036] like Figure 3-4 As shown, the coil assembly includes an insulating assembly 7 and a wire group 2 arranged in the insulating assembly 7, a heat shrink tube 3 is provided on the inner side of the wire group 2, and an iron core 4 is provided on the inner side of the heat shrink tube 3. One end of the wire group 2 extends out of the insulating assembly 7 and is connected to the connecting plate 1, and the other end of the wire group 2 extends out of the insulating assembly 7 and is connected to the portion where the heating element 11 and the bimetallic strip 13 are spaced apart through a soft connection 16. The wire group 2 is used to amplify the magnetic field of the iron core 4, and the amplification of the magnetic field can increase the suction force between the armature 15 and the iron core 4.

[0037] The current path of the thermal electromagnetic release of this embodiment is the connecting plate 1, the wire group 2, the flexible connection 16, and then the parallel heating element 11 and the bimetallic strip 13. Compared with the conventional path of the existing connecting plate, the wire group, the flexible connection 16, the bimetallic strip, and the heating element, the current of the heating element 11 and the bimetallic strip 13 is diverted, which can prevent the bimetallic strip 13 from fusing. In addition, the bimetallic strip 13 can be heated by the heating element 11 while self-heating, thereby improving the consistency of the delayed action.

[0038] like Figure 2 As shown, the iron core 4 and / or the heating element 11 are respectively provided with a boss structure, and the left magnetic yoke 6 and the right magnetic yoke 5 are respectively provided with a through-hole structure corresponding to the boss structure. A convex point structure can be provided on the boss structure, and the boss structure is fixed by riveting after passing through the corresponding through-hole structure. Specifically, the left magnetic yoke 6 and the right magnetic yoke 5 are respectively provided with a first through-hole 190 as a through-hole structure, and the two ends of the iron core 4 are respectively provided with a first boss 19 as a boss structure, and the first boss 19 at the two ends of the iron core 4 are respectively passed through the first through-hole 190 on the left magnetic yoke 6 and the right magnetic yoke 5 and fixed by riveting. The outer sides of the two fixed legs 114 of the heating element 11 are respectively provided with a third boss 116 as a boss structure, and the left magnetic yoke 6 and the right magnetic yoke 5 are respectively provided with a third through-hole 117 corresponding to the third boss 116 and serving as a through-hole structure, and the third boss 116 is respectively passed through the corresponding third through-hole 117 and fixed by riveting.

[0039] Furthermore, the left and right yokes 6 and 5 are each provided with a boss structure, and the left and right plates 8 and 9 are each provided with a through-hole structure corresponding to the boss structure. The boss structure is inserted through the corresponding through-hole structure and then riveted in place. Specifically, the outer sides of the left and right yokes 6 and 5 are each provided with three second bosses 18 serving as the boss structure, and the left and right plates 8 and 9 are each provided with three second through-hole structures corresponding to the second bosses 18. The second bosses 18 on the outer sides of the left and right yokes 6 and 5 are inserted through the corresponding second through-holes 180 and then riveted in place. It is understood that the number and shape of the first bosses 19, second bosses 18, and third bosses 116 are not limited to those shown in the figures. The number and shape of the first bosses 19, second bosses 18, and third bosses 116 can be adjusted, and the number and shape of the first through-holes 190, second through-holes 180, and third through-holes 117 can be matched accordingly. This can reduce the use of screws and rivets and reduce the difficulty of assembly.

[0040] The assembly process of the thermal electromagnetic release of this embodiment is as follows:

[0041] The connecting plate 1 is first welded to one end of the wire group 2, and the heat shrink tube 3 is heated to wrap around the iron core 4, and then inserted into the wire group 2 and the insulating assembly 7. The heating element 11 and the bimetallic strip 13 are riveted together through the conductive member 12. The left yoke 6 and the right yoke 5 are then respectively installed on the heating element 11. The armature 15 is then installed on the left plate 8 and the right plate 9. When assembling the protrusion 151 and the groove 22, it is important to lock them into place. Finally, the left yoke and the armature 15 are respectively connected through the spring 10. The bimetallic strip 13 of this embodiment can fully utilize the structural characteristics of other components, shunting the large current on the bimetallic strip 13 during disconnection, thereby preventing the bimetallic strip 13 from being burned. At the same time, it takes into account the self-heating of the direct-heating bimetal and the heating of the indirectly heated heating element, ensuring the reliability of the product's delayed action.

[0042] like Figure 7-8 As shown in the figure, A1-A4 is the direction of current flow in the heating element 11, and B1-B4 is the newly added parallel circuit. Since the resistance of the heating element 11 is small, most of the current will flow in the direction of A1-A4, and a smaller part will flow in the direction of B1-B4. Figure 7 The parallel connection begins at the left-hand spacing slot 110. Current A1 is split into two directions, A2 and B1, flowing through heating element 11 and bimetallic strip 13, respectively. The current in heating element 11 flows sequentially through A2-A4, and in bimetallic strip 13, B1-B4, before converging at flexible connector 16 to form currents A5-A6. The U-shaped design of heating element 11 and bimetallic strip 13 reduces the conductor's cross-sectional area and extends the current path, effectively increasing heat generation and avoiding the problem of insufficient heating with low ampere currents.

[0043] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A thermal electromagnetic release, characterized in that: The invention comprises a bracket, a coil assembly and a heating assembly respectively mounted on the bracket, wherein the heating assembly comprises a heating element (11) and a bimetallic strip (13), the heating element (11) is electrically connected to the coil assembly, and the bimetallic strip (13) is connected in parallel with the heating element (11) via a conductive member (12); the heating element (11) comprises a heating portion and a fixing portion, the heating portion is provided with a second slot (111), the heating portion comprises two heating strips (112) arranged on both sides of the second slot (111), and a heating strip (113) connected between one ends of the two heating strips (112), wherein The other end of one heating strip (112) is respectively connected to one end of the bimetallic strip (13) and the fixing portion, and the other end of another heating strip (112) is connected to one end of the bimetallic strip (13) and is spaced apart from the fixing portion. The bimetallic strip comprises at least two spaced-apart bimetallic strips (132), one end of at least two bimetallic strips (132) are connected together through a bimetallic connecting piece (133), and the other ends of at least two bimetallic strips (132) are respectively fixed to the heating strip (112) through a conductive member (12), and the heating portion and other parts of the bimetallic strip (13) are spaced apart.

2. The thermal electromagnetic release according to claim 1, characterized in that: The bimetallic strip (13) is integrally formed into a U-shaped structure. A slot (131) is provided in the middle of the bimetallic strip (13). The bimetallic strip (13) comprises two bimetallic strips (132) arranged opposite to each other on both sides of the slot (131), and a bimetallic connecting piece (133) connected between one ends of the two bimetallic strips (132). The other ends of the two bimetallic strips (132) are fixed to the heating element (11) via conductive members (12).

3. The thermal electromagnetic release according to claim 1, characterized in that: The heating part has a U-shaped structure.

4. The thermal electromagnetic release according to claim 3, characterized in that: One end of the two heating strips (112) connected to the heating plate (113) is bent toward a side away from the bimetallic strip (13), forming a spacing groove (110) between the heating element (11) and the bimetallic strip (13).

5. The thermal electromagnetic release according to claim 1, characterized in that: The invention also includes an armature (15) rotatably mounted on a bracket, wherein the coil assembly includes an insulating assembly (7) and a wire group (2) arranged in the insulating assembly (7), an iron core (4) is provided on the inner side of the wire group (2), one end of the wire group (2) is connected to the connecting plate (1), and the other end is connected to the portion where the heating element (11) and the bimetallic strip (13) are spaced apart through a flexible connection (16).

6. The thermal electromagnetic release according to claim 5, characterized in that: The bracket comprises a left side plate (8) and a right side plate (9) which are arranged opposite to each other. A left magnetic yoke (6) and a right magnetic yoke (5) are fixedly mounted on the inner sides of the left side plate (8) and the right side plate (9), respectively. The left magnetic yoke (6) and the right magnetic yoke (5) are arranged opposite to each other on both sides of the coil assembly.

7. The thermal electromagnetic release according to claim 5, characterized in that: A heat shrink tube (3) is provided on the inner side of the wire group (2) and is included on the iron core (4).

8. The thermal electromagnetic release according to claim 6, characterized in that: The armature (15) is provided with protrusions (151) on both sides, and the top sides of the left side plate (8) and the right side plate (9) are respectively provided with grooves (22) in a U-shaped structure. The protrusions (151) can be respectively inserted into the corresponding grooves (22) of the left side plate (8) and the right side plate (9) and rotated. The left side plate (8) and the right side plate (9) are respectively provided with limiting parts (23) for limiting the armature (15) on the side close to the armature (15).

9. The thermal electromagnetic release according to claim 6, characterized in that: The iron core (4) and / or the heating element (11) are respectively provided with boss structures, and the left magnetic yoke (6) and the right magnetic yoke (5) are respectively provided with through-hole structures corresponding to the boss structures, and the boss structures are fixed by riveting after passing through the corresponding through-hole structures.

10. The thermal electromagnetic release according to claim 6, characterized in that: The left magnetic yoke (6) and the right magnetic yoke (5) are respectively provided with boss structures, and the left side plate (8) and the right side plate (9) are respectively provided with through-hole structures corresponding to the boss structures, and the boss structures are fixed by riveting after passing through the corresponding through-hole structures.

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