Thermal relay

Abstract

The utility model belongs to the technical field of relays, and particularly relates to a thermal relay, which comprises a shell provided with three partition plates. Each thermosensitive unit comprises a limiting block, a metal ring and a heating device, the heating device comprises a heating plate, a fixing plate, a wire inlet port and a wire outlet port, the limiting block is recessed inwards from the side wall to form a recessed part, the metal ring is arranged in the recessed part, and the heating plate is wrapped by the metal ring; each transmission unit comprises a connecting block, an elastic piece and a transmission plate; and the switching unit comprises a guide plate, a push rod, a normally-closed contact and a movable contact, one end of the guide plate is connected with the push rod, the movable contact is fixedly connected with the side wall of the partition plate close to the push rod, the normally-closed contact is fixed on the push rod, and the normally-closed contact and the movable contact are correspondingly arranged. The thermal relay is high in reaction speed and effectively prevents overload damage of the motor.

Description

Technical Field

[0001] The utility model belongs to the technical field of relays, and in particular relates to a thermal relay. Background Art

[0002] A thermal relay is a protective device used to control motors and other high-power equipment. The device disconnects the circuit and prevents equipment from overload failure by deforming bimetallic strips with different expansion coefficients.

[0003] However, the existing thermal relays still have the following problems: there is a certain distance between the bimetallic strip and the heating element in the thermal relay and the relative heat transfer area between the two is insufficient, resulting in the deformation of the bimetallic strip. It takes a certain amount of reaction time for the bimetallic strip to bend due to heat and push the guide part to disconnect the circuit. Too long a reaction time can easily lead to overload and damage of the electrical appliance. Utility Model Content

[0004] The utility model aims to solve the problem of slow response of current thermal relays described in the above background technology, and proposes a new thermal relay which has a faster response speed so that the circuit is disconnected in time to protect the electrical appliances.

[0005] A technical solution adopted to achieve the above-mentioned purpose is a thermal relay, the thermal relay comprising:

[0006] A shell, wherein the shell is provided with three partition plates, and the three partition plates penetrate through the top wall of the shell and are fixed;

[0007] Three thermal units, the thermal units include a limit block, a metal ring and a heating device, the heating device includes a heating plate, a fixing plate, an inlet port and an outlet port, one end of the heating plate is connected to the fixing plate, and the other end of the heating plate is connected to the inlet port and the outlet port, the limit block is recessed from the side wall to the inside to form a recessed portion, the metal ring is arranged in the recessed portion, and the metal ring wraps the heating plate;

[0008] Three transmission units, the transmission units include a connecting block, an elastic member and a transmission plate, the connecting block is fixedly connected to the partition plate, the elastic member connects the transmission plate and the connecting block, and the top end of the transmission plate is rotatably connected to the inner wall of the shell;

[0009] A switching unit, the switching unit includes a guide plate, a push rod, a normally closed contact and a moving contact, one end of the guide plate is connected to the push rod, the moving contact is fixedly connected to the side wall of the partition plate close to the push rod, the normally closed contact is fixed on the push rod, and the normally closed contact and the moving contact are arranged correspondingly.

[0010] In the above technical solution, three thermistor units and three transmission units that cooperate with each other are set up, corresponding to the three-phase motor, and a metal ring is used to wrap the heating plate so that heat is directly conducted from the heating plate to the metal ring, so that the metal ring reaches the deformation temperature faster and deforms, thereby disconnecting the contacts and protecting the electrical appliance.

[0011] Furthermore, the thermal relay also includes a reset unit, which includes a pressing block, a reset spring and a push rod, the reset spring connects the pressing block and the push rod, the pressing block is located outside the shell, and the push rod passes through the side wall of the shell and extends into the interior of the shell.

[0012] Furthermore, the push rod and the guide plate are in the same horizontal plane.

[0013] In the above technical solution, the pressing block is squeezed to push the push rod to move horizontally, and the push rod pushes the push rod to move horizontally, and the push rod drives the guide plate to move and reset, thereby realizing the position restoration of each component in the thermal relay and reusing the thermal relay.

[0014] Furthermore, the heating plate and the fixing plate are vertically connected, and the fixing plate is fixedly connected to the inner wall of the shell.

[0015] In the above technical solution, the heating device is fixed by vertical connection to achieve the stability of the device.

[0016] Furthermore, the metal ring is square, and the top wall, the bottom wall and one side wall of the metal ring are attached to and fixed to the recessed portion.

[0017] In the above technical solution, the metal ring is similar to a rectangular reel, and three sides of the metal ring are fixed to the recessed portion. When the motor is overloaded, the three sides of the metal ring are fixed, and the deformation can only be toward the unfixed side. Due to the expansion and bending of the metal, the metal ring will protrude toward the unfixed side, thereby pushing the transmission plate.

[0018] Furthermore, the three thermal units and the three transmission units are matched one by one, and the transmission plate is located between the connecting block and the limiting block.

[0019] In the above technical solution, the three thermal units and the three transmission units correspond to the three items of the motor respectively to prevent the motor from being overloaded.

[0020] Furthermore, the top end of the transmission plate is hinged to the inner wall of the shell.

[0021] In the above technical solution, the hinge enables the transmission plate to rotate relative to the top, and when the motor is overloaded, the metal ring with the deformed protrusion can push the transmission plate to rotate, thereby disconnecting the contacts.

[0022] Furthermore, a heat insulation plate is provided between the metal ring and the recessed portion.

[0023] In the above technical solution, the heat insulation board plays a protective role to prevent the heat of the heating plate from being transmitted to the outside along the limit block and causing damage to the thermal relay.

[0024] Furthermore, the three limit blocks are respectively fixedly connected to the side wall of the shell away from the switching unit and the two partition plates.

[0025] The advantages of the utility model are:

[0026] 1. The utility model realizes rapid heat conduction through the direct contact between the metal ring and the heating plate, thereby accelerating the response speed of the thermal relay.

[0027] 2. The metal ring of the utility model can be made of not only bimetal but also single metal with suitable expansion coefficient. The expansion deformation direction of the metal ring can be adjusted by the limiting direction of the limiting block. When single metal is used, the problems of loose bimetal composite and deflection that may exist in bimetal are avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the structure of the utility model;

[0030] Figure 2 It is a side view of the heating device of the utility model;

[0031] Figure 3 It is the front view of the heating device of the utility model.

[0032] Illustrations: 1. Shell, 2. Thermistor unit, 3. Transmission unit, 4. Switching unit, 5. Reset unit, 101. Partition plate, 201. Limit block, 202. Metal ring, 203. Heating plate, 204. Fixing plate, 205. Inlet port, 206. Outlet port, 301. Connecting block, 302. Elastic member, 303. Transmission plate, 401. Guide plate, 402. Push rod, 403. Normally closed contact, 404. Moving contact, 501. Pressing block, 502. Reset spring, 503. Push rod. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] like Figure 1 As shown, a thermal relay is composed of a shell 1, three thermistor units 2, three transmission units 3, a switching unit 4 and a reset unit 5, wherein the shell 1 is provided with three partition plates 101, and the three partition plates 101 pass through the top wall of the shell 1 and are fixed, and the three partition plates 101 divide the interior of the shell 1 into four areas, and a thermistor unit 2 and a transmission unit 3 are respectively provided in the three areas on the right.

[0036] The three thermal sensing units 2 are all composed of a limit block 201, a metal ring 202 and a heating device. Figure 2-3 As shown, the heating device consists of a heating plate 203, a fixed plate 204, an inlet port 205 and an outlet port 206, wherein a limit block 201 is fixedly connected to the right inner wall of the shell 1, and the other two limit blocks 201 are respectively fixedly connected to the left sides of the two partition plates on the right side of the shell 1, the fixed plate 204 is fixedly connected to the inner wall of the shell 1, one end of the heating plate 203 is vertically connected to the fixed plate 204, and the other end of the heating plate 203 is fixedly connected to the inlet port 205 and the outlet port 206, which are separated at both ends, the limit block 201 is recessed inward from the left side to form a recessed portion, and its shape is similar to a "U" shape, the metal ring 202 is arranged in the recessed portion, and the heating plate 203 is arranged inside the metal ring 202.

[0037] The metal ring 202 is in the shape of a square tube, and the upper and lower right sides of the metal ring 202 are in contact with the recess and are fixed in position. A heat insulation plate can be provided between the metal ring 202 and the recess to prevent the heat conduction of the heating plate 203 from damaging other components such as the housing 1.

[0038] The three transmission units 3 are all composed of a connecting block 301, an elastic member 302 and a transmission plate 303. The three connecting blocks 301 are respectively fixedly connected to the bottom right side of the partition plate 101. The elastic member 302 connects the transmission plate 303 and the connecting block 301. The elastic member 302 plays a role in supporting and stabilizing the transmission plate 303 to prevent the transmission plate 303 from shaking violently during movement and causing damage to the thermal relay. The top of the transmission plate 303 is hinged to the inner wall of the shell 1 to achieve free rotation of the transmission plate 303 relative to its top.

[0039] The switching unit 4 is composed of a guide plate 401, a push rod 402, a normally closed contact 403 and a moving contact 404. The switching unit 4 is the prior art. The guide plate 401 is arranged below the partition plate 101. The left end of the guide plate 401 is connected or in contact with the push rod 402. The moving contact 404 is fixed on the push rod 402. The normally closed contact 403 is arranged on the leftmost partition plate 101. Under normal circumstances, the normally closed contact 403 and the moving contact 404 maintain contact.

[0040] The reset unit 5 is composed of a pressing block 501, a reset spring 502 and a push rod 503. The reset spring 502 connects the pressing block 501 and the push rod 503. The pressing block 501 is located outside the shell 1. The push rod 503 passes through the side wall of the shell 1 and extends into the interior of the shell 1. The push rod 503 is on the same horizontal plane as the guide plate 401, which is convenient for pushing the push rod 402 when reset is needed.

[0041] The working principle of the utility model is as follows: the current passes through the incoming port 205, the heating plate 203 and the outgoing port 206 in sequence. When the motor is overloaded, the current increases, the heating plate 203 heats up, and the heat generated by the heating plate 203 is directly transferred to the metal ring 202. Since the upper and lower right sides of the metal ring 202 are limited and fixed, the metal ring 202 is forced to deform and bulge to the left. After the metal ring 202 bulges, it pushes the transmission plate 303 to rotate to the left. The transmission plate 303 drives the guide plate 401 to move to the left. The guide plate 401 drives the push rod to rotate, and the normally closed contact 403 and the moving contact 404 are separated, thereby disconnecting the circuit.

[0042] Finally, it should be noted that this embodiment is only used to illustrate the present invention and does not limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A thermal relay, characterized in that: The thermal relay comprises: A shell (1), wherein the shell (1) is provided with three partition plates (101), and the three partition plates (101) penetrate through the top wall of the shell (1) and are fixed; Three thermal sensing units (2), the thermal sensing units (2) comprising a stop block (201), a metal ring (202) and a heating device, the heating device comprising a heating plate (203), a fixing plate (204), an inlet port (205) and an outlet port (206), one end of the heating plate (203) being connected to the fixing plate (204), the other end of the heating plate (203) being connected to the inlet port (205) and the outlet port (206), the stop block (201) being recessed from the side wall to the inside to form a recessed portion, the metal ring (202) being arranged in the recessed portion, and the metal ring (202) wrapping the heating plate (203); Three transmission units (3), the transmission units (3) comprising a connecting block (301), an elastic member (302) and a transmission plate (303), the connecting block (301) being fixedly connected to the partition plate (101), the elastic member (302) connecting the transmission plate (303) and the connecting block (301), and the top end of the transmission plate (303) being rotatably connected to the inner wall of the housing (1); A switching unit (4), the switching unit (4) comprising a guide plate (401), a push rod (402), a normally closed contact (403) and a moving contact (404), one end of the guide plate (401) being connected to the push rod (402), the moving contact (404) being fixedly connected to a side wall of a partition plate (101) close to the push rod (402), the normally closed contact (403) being fixed on the push rod (402), and the normally closed contact (403) and the moving contact (404) being arranged correspondingly.

2. The thermal relay according to claim 1, characterized in that: The thermal relay further comprises a reset unit (5), wherein the reset unit (5) comprises a pressing block (501), a reset spring (502) and a push rod (503), wherein the reset spring (502) connects the pressing block (501) and the push rod (503), wherein the pressing block (501) is located outside the shell (1), and the push rod (503) penetrates the side wall of the shell (1) and extends into the interior of the shell (1).

3. The thermal relay according to claim 2, characterized in that: The pushing rod (503) and the guide plate (401) are located at the same horizontal plane.

4. The thermal relay according to claim 1, characterized in that: The heating plate (203) and the fixing plate (204) are vertically connected, and the fixing plate (204) is fixedly connected to the inner wall of the shell (1).

5. The thermal relay according to claim 1, characterized in that: The metal ring (202) is square, and the top wall, the bottom wall and one side wall of the metal ring (202) are attached to and fixed to the recessed portion.

6. The thermal relay according to claim 1, characterized in that: The three thermal-sensitive units (2) and the three transmission units (3) are matched one by one, and the transmission plate (303) is located between the connecting block (301) and the limiting block (201).

7. The thermal relay according to claim 1, characterized in that: The top end of the transmission plate (303) is hinged to the inner wall of the housing (1).

8. The thermal relay according to claim 1, characterized in that: A heat insulation plate is provided between the metal ring (202) and the recessed portion.

9. The thermal relay according to claim 1, characterized in that: The three limit blocks (201) are respectively fixedly connected to the side wall of the housing (1) away from the switching unit (4) and the two partition plates (101).

Images