Silicon carbide diode sealing bridge rectifier module
By integrating the silicon carbide diode into the same package, forming a bridge rectifier circuit and controlling heat dissipation using the thermal expansion mechanism, the complex installation and heat dissipation problems in traditional rectifier bridge design are solved, and efficient and reliable rectifier effects and overheating protection are achieved.
Patent Information
- Application Number
- CN202510045998.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2025-04-18
AI Technical Summary
In traditional rectifier bridge design, each diode is independently packaged, resulting in complex installation and serious heat dissipation problems, affecting the compactness and reliability of the module.
The silicon carbide diode-sealed bridge rectifier module is adopted to form a complete bridge rectifier circuit by integrating four diodes in the same package, and the thermal expansion mechanism of the shrapnel and trigger plates control the switch of the heat dissipation component to achieve overheating protection.
The module size is reduced, the rectification efficiency and reliability are improved, and the rectification needs of high frequency and high efficiency can be met, and the diode breakdown is prevented through automatic overheating protection.
Smart Images
Figure CN119853408A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of diode sealed bridge rectifier modules, and in particular to a silicon carbide diode sealed bridge rectifier module. Background Art
[0002] The bridge rectifier module is a commonly used power electronic device, mainly used to convert alternating current (AC) into direct current (DC). It consists of four diodes connected in a specific bridge circuit. This configuration allows the output current direction to remain consistent regardless of whether the input AC voltage is in the positive half-cycle or the negative half-cycle, thereby achieving full-wave rectification. In this way, the bridge rectifier can effectively utilize every cycle of the AC power supply, provide more efficient energy conversion than half-wave rectification, and its output DC voltage is more stable. In addition, modern bridge rectifier modules usually integrate protection and filtering functions, can adapt to different load requirements, and are widely used in various devices that require DC power supply, such as chargers, switching power supplies, and industrial control systems.
[0003] In traditional rectifier bridge designs, individual diodes are often packaged independently and connected through circuits. This design not only increases the overall volume, but also leads to increased installation complexity and heat dissipation problems. Since each diode is handled and installed individually, this makes the entire assembly process more cumbersome and increases the probability of error. In addition, additional wiring is required between the independently packaged diodes to complete the connection of the bridge circuit. These wiring takes up space and affects the compactness of the module. Moreover, the decentralized diode layout is not conducive to effective heat management because they cannot fully utilize the heat sink or cooling system, which may lead to reduced efficiency and reliability issues.
[0004] How to invent a silicon carbide diode sealed bridge rectifier module to improve these problems has become an urgent problem to be solved by technical personnel in this field. Summary of the invention
[0005] In order to make up for the above shortcomings, the present invention provides a silicon carbide diode sealed bridge rectifier module, aiming to improve the problems mentioned in the above background.
[0006] The present invention is achieved in that: The present invention provides a silicon carbide diode sealed bridge rectifier module, comprising a module housing, a module cover plate fixedly connected to one side of the module housing, a heat conducting plate fixedly connected to the outer side wall of the module cover plate, a fan shield arranged on one side of the heat conducting plate, and further comprising: A heat dissipation component, which is arranged on the inner side of the fan shield and is used for heat dissipation of the module; A trigger component, which is arranged on one side of the heat conducting plate and is used to control the switch of the heat dissipation component and the overheat protection of the module; The module assembly is arranged on the inner side of the module housing and is used for rectifying the circuit.
[0007] Preferably, a plurality of heat sinks are fixedly connected to the side wall of the heat conducting plate, the heat sinks are arranged in a thin sheet shape, the plurality of heat sinks are equidistantly arranged in a vertical direction of the heat conducting plate, and a support plate is fixedly connected to the plurality of heat sinks.
[0008] Preferably, the trigger assembly includes a shell fixedly connected to the side wall of the support plate, a circular cavity is provided between the plurality of the heat dissipation plates, the shell is located on the inner side of the circular cavity, the side wall of the heat conducting plate is fixedly connected to a plurality of fixing pins, the plurality of fixing pins are fixedly connected to spring sheets, a trigger sheet is provided on the spring sheets, the spring sheets and the trigger sheet are made of two metals with different expansion coefficients, the two metals are located on both sides of the spring sheets, the shell is fixedly connected to a side cover, the side cover is provided with a stabilizing sleeve, the stabilizing sleeve is arranged in a circular tube shape, a first push rod and a second push rod are slidably provided inside the stabilizing sleeve, the first push rod and the second push rod are provided with a buffer spring, the two ends of the buffer spring are respectively fixedly connected to the first push rod and the second push rod, a first guide piece and a second guide piece are fixedly connected to the shell, the ends of the first guide piece and the second guide piece are fixedly connected to contacts, and the two contacts are arranged in a non-contact manner.
[0009] Preferably, the spring piece is arranged in a circular ring shape, and the spring piece is arranged non-fittingly on the side wall of the heat conducting plate.
[0010] Preferably, the trigger assembly also includes an auxiliary plate fixedly connected to the second guide plate, the inner wall of the side cover is fixedly connected to a support column, the auxiliary plate and the support column are both fixedly connected to contacts, and the two contacts are arranged in a close fit, the side cover is rotatably connected to a third guide plate, the side wall of the third guide plate is fixedly connected to a connecting plate, the third guide plate is fixedly connected to a pressing spring, the end of the pressing spring is fixedly connected to the side cover, the side cover is fixedly connected to an iron core, the outer side wall of the iron core is wound with a coil, an iron plate is arranged above the iron core, the iron plate is fixedly connected to the third guide plate, the inner wall of the side cover is fixedly connected to a fourth guide plate, and the ends of the third guide plate and the fourth guide plate are both provided with contacts.
[0011] Preferably, the first guide piece, the second guide piece, the connecting piece and the fourth guide piece all extend to the outside of the housing side.
[0012] Preferably, the heat dissipation assembly includes a motor fixedly connected to the side wall of the support plate, the output shaft of the motor is fixedly connected to a rotating sleeve, the outer side wall of the rotating sleeve is fixedly connected to blades, and the blades are evenly distributed on the side wall of the rotating sleeve.
[0013] Preferably, the first guide plate and the second guide plate are connected between the power lines of the motor, the contacts on the auxiliary plate and the contacts on the support column are connected between the power lines of the coil, and the connecting plate and the fourth guide plate are connected between the power lines of the module assembly.
[0014] Preferably, the module assembly includes a stabilizing member fixedly connected to the inner wall of the module housing, and a first contact piece, a second contact piece, a third contact piece and a fourth contact piece are fixedly connected to the stabilizing member, two connection points are fixedly connected to the first contact piece, a semiconductor diode and a connection point are fixedly connected to the second contact piece and the third contact piece, and two semiconductor diodes are fixedly connected to the fourth contact piece.
[0015] Preferably, the semiconductor diode is made of silicon carbide, and insulating thermally conductive silicone grease is filled between the first contact sheet, the second contact sheet, the third contact sheet, the fourth contact sheet and the module cover.
[0016] The beneficial effects of the present invention are as follows: the module integrates four silicon carbide diodes in the same package to form a complete bridge rectifier circuit, thereby reducing the module volume and meeting the high-frequency and high-efficiency rectification requirements; The temperature increase of the diode causes the spring to deform, so that the trigger plate drives the second push rod to move in the direction of the first guide plate, pushing the contact on the first guide plate to contact the contact on the second guide plate, so that the motor drives the multiple blades to rotate, generating a flowing airflow, cooling the module, and preventing the diode in the module from reducing the switching speed due to the temperature increase; If the temperature continues to rise, the trigger plate continues to push the first guide plate to move in the direction of the second guide plate, so that the auxiliary plate is separated from the support column. The iron core loses its magnetic force, so that the third guide plate is separated from the fourth guide plate, the module assembly is powered off, and the module stops working, preventing the risk of diode breakdown due to overtemperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0018] Figure 1It is a schematic diagram of the three-dimensional structure of a silicon carbide diode sealed bridge rectifier module provided in an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of a heat sink of a silicon carbide diode sealed bridge rectifier module provided in an embodiment of the present invention; Figure 3 It is a schematic diagram of a spring structure of a silicon carbide diode sealed bridge rectifier module provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the internal structure of a silicon carbide diode sealed bridge rectifier module housing provided in an embodiment of the present invention; Figure 5 It is a schematic diagram of the contact connection position of a silicon carbide diode sealed bridge rectifier module provided in an embodiment of the present invention; Figure 6 It is a schematic structural diagram of a heat dissipation component of a silicon carbide diode sealed bridge rectifier module provided in an embodiment of the present invention; Figure 7 It is a schematic diagram of the structure of a silicon carbide diode sealed bridge rectifier module module assembly provided in an embodiment of the present invention.
[0019] In the figure: 1. module housing; 2. module cover; 3. heat conduction plate; 4. fan shield; 5. heat sink; 6. support plate; 7. housing; 11. fixing pin; 12. spring; 13. trigger plate; 14. side cover; 15. stabilizing sleeve; 16. first push rod; 17. buffer spring; 18. second push rod; 19. first guide plate; 20. second guide plate; 21. auxiliary plate; 22. support column; 23. third guide plate; 24. connecting plate; 25. pressing spring; 26. coil; 27. iron core; 28. iron plate; 29. fourth guide plate; 31. motor; 32. rotating sleeve; 33. blade; 40. stabilizing member; 41. first contact plate; 42. second contact plate; 43. third contact plate; 44. fourth contact plate; 45. connecting point; 46. semiconductor diode. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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 part of the embodiments of the present invention, not 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 are within the scope of protection of the present invention.
[0021] Example, see Figure 1-Figure 3A silicon carbide diode sealed bridge rectifier module includes a module housing 1, a module cover 2 is fixedly connected to one side of the module housing 1, a heat conducting plate 3 is fixedly connected to the outer wall of the module cover 2, a fan shield 4 is arranged on one side of the heat conducting plate 3, and also includes: a heat dissipation component, the heat dissipation component is arranged on the inner side of the fan shield 4, and the heat dissipation component is used for heat dissipation of this module; a trigger component, the trigger component is arranged on one side of the heat conducting plate 3, and the trigger component is used to control the switch of the heat dissipation component and the overheating protection of this module; a module component, the module component is arranged on the inner side of the module housing 1, and the module component is used for circuit rectification. A plurality of heat dissipation plates 5 are fixedly connected to the side wall of the heat conducting plate 3, and the heat dissipation plates 5 are arranged in a thin sheet shape, and the plurality of heat dissipation plates 5 are arranged equidistantly in the vertical direction of the heat conducting plate 3, and a support plate 6 is fixedly connected to the plurality of heat dissipation plates 5.
[0022] Reference Figure 4-Figure 5 The trigger assembly includes a shell 7 fixedly connected to the side wall of the support plate 6, a circular cavity is arranged between the plurality of heat dissipation plates 5, the shell 7 is located inside the circular cavity, a plurality of fixing pins 11 are fixedly connected to the side wall of the heat conducting plate 3, a plurality of springs 12 are fixedly connected to the plurality of fixing pins 11, a trigger piece 13 is arranged on the spring piece 12, the spring piece 12 and the trigger piece 13 are made of two metals with different expansion coefficients, the two metals are arranged on the two sides of the spring piece 12, a side cover 14 is fixedly connected to the shell 7, a stabilizing sleeve 15 is arranged on the side cover 14, and a stabilizing sleeve 15 is arranged on the side cover 14. The sleeve 15 is arranged in a circular tubular shape, and a first push rod 16 and a second push rod 18 are slidingly arranged inside the stabilizing sleeve 15. The first push rod 16 and the second push rod 18 are provided with a buffer spring 17, and the two ends of the buffer spring 17 are respectively fixedly connected to the first push rod 16 and the second push rod 18. A first guide plate 19 and a second guide plate 20 are fixedly connected to the outer shell 7, and the ends of the first guide plate 19 and the second guide plate 20 are fixedly connected with contacts, and the two contacts are arranged non-contactingly, and the spring piece 12 is arranged in a circular ring shape, and the spring piece 12 is arranged non-fittingly to the side wall of the heat conducting plate 3.
[0023] It should be noted that the two sides of the spring 12 are made of constantan (copper-nickel alloy) and brass (copper-zinc alloy), respectively. The side made of constantan is closer to the heat conducting plate 3. When the temperature of the spring 12 rises, since the thermal expansion coefficient of brass is higher than that of constantan, the spring 12 will bend toward the constantan side, causing the trigger sheet 13 to move away from the heat conducting plate 3.
[0024] The trigger assembly also includes an auxiliary piece 21 fixedly connected to the second guide piece 20, a support column 22 is fixedly connected to the inner wall of the side cover 14, the auxiliary piece 21 and the support column 22 are both fixedly connected with contacts, and the two contacts are arranged in a close fit, a third guide piece 23 is rotatably connected to the side cover 14, a connecting piece 24 is fixedly connected to the side wall of the third guide piece 23, a pressing spring 25 is fixedly connected to the third guide piece 23, and the end of the pressing spring 25 is fixedly connected to the side cover 14, an iron core 27 is fixedly connected to the side cover 14, a coil 26 is wound around the outer wall of the iron core 27, an iron plate 28 is arranged above the iron core 27, the iron plate 28 is fixedly connected to the third guide piece 23, a fourth guide piece 29 is fixedly connected to the inner wall of the side cover 14, contacts are arranged at the ends of the third guide piece 23 and the fourth guide piece 29, and the first guide piece 19, the second guide piece 20, the connecting piece 24 and the fourth guide piece 29 all extend to the outer side of the shell 7.
[0025] Reference Figure 6 The heat dissipation component includes a motor 31 fixedly connected to the side wall of the support plate 6, the output shaft of the motor 31 is fixedly connected to a rotating sleeve 32, the outer side wall of the rotating sleeve 32 is fixedly connected to blades 33, and the blades 33 are evenly distributed on the side wall of the rotating sleeve 32.
[0026] The first guide plate 19 and the second guide plate 20 are connected between the power lines of the motor 31, the contacts on the auxiliary plate 21 and the contacts on the support column 22 are connected between the power lines of the coil 26, and the connecting plate 24 and the fourth guide plate 29 are connected between the power lines of the module assembly.
[0027] It should be noted that when the coil 26 is energized, due to the principle of electromagnetic induction, the iron core 27 is magnetized and adsorbs the iron plate 28 above, so that the third guide piece 23 overcomes the elastic force of the pressing spring 25 and the end moves toward the side cover 14, so that the contact on the third guide piece 23 contacts the contact on the fourth guide piece 29. Since the connecting piece 24 and the fourth guide piece 29 are connected between the power lines of the module assembly, when the third guide piece 23 contacts the fourth guide piece 29 through the contact, the module assembly is in a state of being powered on, and the module assembly starts working for rectification operation.
[0028] Reference Figure 7 The module assembly includes a stabilizing member 40 fixedly connected to the inner wall of the module housing 1, and a first contact piece 41, a second contact piece 42, a third contact piece 43 and a fourth contact piece 44 are fixedly connected to the stabilizing member 40, two connection points 45 are fixedly connected to the first contact piece 41, and a semiconductor diode 46 and a connection point 45 are fixedly connected to the second contact piece 42 and the third contact piece 43, and two semiconductor diodes 46 are fixedly connected to the fourth contact piece 44. Insulating thermal conductive silicone grease is filled between the first contact piece 41, the second contact piece 42, the third contact piece 43, the fourth contact piece 44 and the module cover plate 2.
[0029] It should be noted that since the semiconductor diode 46 is made of silicon carbide, the silicon carbide diode has significantly improved the performance and efficiency of the power electronic system with its advantages such as high temperature working capability, high efficiency, fast switching speed, high voltage tolerance, low reverse leakage current and low switching capacitance. This module integrates four silicon carbide diodes in the same package to form a complete bridge rectifier circuit, which reduces the module size and can meet the high-frequency and high-efficiency rectification requirements.
[0030] In this embodiment, since heat is generated when current passes through the diode, especially in a circuit with a large current change, the greater the current, the more heat is generated, resulting in an increase in the temperature of the rectifier module, which not only reduces the switching speed of the diode, but also reduces its breakdown voltage, increasing the risk of diode breakdown. By setting the spring 12, when the temperature of the diode rises, the thermal grease transfers the heat to the heat conducting plate 3 and the spring 12, causing the spring 12 to deform, and the trigger piece 13 moves in a direction away from the heat conducting plate 3. The higher the temperature, the greater the displacement of the trigger piece 13, thereby pushing the first push rod 16, and pushing the second push rod 18 to move in the direction of the first guide piece 19 through the buffer spring 17, pushing the contact on the first guide piece 19 to contact the contact on the second guide piece 20. Since the first guide piece 19 and the second guide piece 20 are connected between the power lines of the motor 31, the motor 31 is powered on, and the output shaft of the motor 31 drives the multiple blades 33 to rotate through the rotating sleeve 32, generating a flowing airflow, cooling the module, and preventing the problem of a decrease in the switching speed of the diode due to the increase in temperature; When the module encounters an abnormal temperature rise caused by factors such as external heat dissipation failure, the spring 12 undergoes a greater deformation, and the trigger piece 13 continues to push the first guide piece 19 to move in the direction of the second guide piece 20. The second guide piece 20 drives the auxiliary piece 21 to separate from the support column 22. Since the contacts on the auxiliary piece 21 and the contacts on the support column 22 are connected between the power lines of the coil 26, the power supply of the coil 26 is cut off, so that the iron core 27 no longer has magnetic force. Due to the thrust of the pressing spring 25, the third guide piece 23 is separated from the fourth guide piece 29. Since the connecting piece 24 is connected to the third guide piece 23 and connected to the fourth guide piece 29 between the power lines of the module assembly, the separation action cuts off the power to the module assembly and stops the operation of the module to prevent the risk of diode breakdown due to excessive temperature. By making the iron core 27 lose its magnetic force, the third guide piece 23 and the fourth guide piece 29 are quickly separated, and the current in the diode is quickly cut off to prevent the contact area change when the contacts are slowly separated from the current instability phenomenon.
[0031] It should be noted that the specific model and specifications of the motor need to be selected and determined based on the actual specifications of the device, and the specific selection calculation method adopts the existing technology in this field, so it will not be described in detail.
[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A silicon carbide diode sealed bridge rectifier module, comprising a module housing (1), a module cover (2) being fixedly connected to one side of the module housing (1), a heat conducting plate (3) being fixedly connected to the outer side wall of the module cover (2), a fan shield (4) being arranged on one side of the heat conducting plate (3), characterized in that: Also includes: A heat dissipation component, the heat dissipation component is arranged on the inner side of the fan shield (4), and the heat dissipation component is used for heat dissipation of the module; A trigger component, the trigger component being arranged on one side of the heat conducting plate (3), and the trigger component being used to control the switch of the heat dissipation component and the overheat protection of the module; A module assembly is arranged on the inner side of a module housing (1), and is used for rectifying a circuit.
2. The silicon carbide diode sealed bridge rectifier module according to claim 1, characterized in that: A plurality of heat dissipation plates (5) are fixedly connected to the side wall of the heat conducting plate (3); the heat dissipation plates (5) are arranged in a thin sheet shape; the plurality of heat dissipation plates (5) are arranged equidistantly in a vertical direction of the heat conducting plate (3); and a support plate (6) is fixedly connected to the plurality of heat dissipation plates (5).
3. The silicon carbide diode sealed bridge rectifier module according to claim 2, characterized in that: The trigger assembly comprises a shell (7) fixedly connected to the side wall of the support plate (6); a circular cavity is provided between the plurality of heat dissipation plates (5); the shell (7) is located inside the circular cavity; a plurality of fixing pins (11) are fixedly connected to the side wall of the heat conducting plate (3); a plurality of springs (12) are fixedly connected to the plurality of fixing pins (11); a trigger sheet (13) is provided on the spring sheet (12); the spring sheet (12) and the trigger sheet (13) are made of two metals with different expansion coefficients; the two metals are located on two sides of the spring sheet (12); a side cover (14) is fixedly connected to the shell (7); the side cover (14) The cover (14) is provided with a stabilizing sleeve (15), the stabilizing sleeve (15) being in the shape of a circular tube, a first push rod (16) and a second push rod (18) being slidably arranged inside the stabilizing sleeve (15), the first push rod (16) and the second push rod (18) being provided with a buffer spring (17), the two ends of the buffer spring (17) being respectively fixedly connected to the first push rod (16) and the second push rod (18), the housing (7) being fixedly connected with a first guide piece (19) and a second guide piece (20), the ends of the first guide piece (19) and the second guide piece (20) being fixedly connected with contacts, and the two contacts being arranged in a non-contact manner.
4. The silicon carbide diode sealed bridge rectifier module according to claim 3, characterized in that: The spring piece (12) is arranged in a circular ring shape, and the spring piece (12) is arranged non-contactingly on the side wall of the heat conducting plate (3).
5. The silicon carbide diode sealed bridge rectifier module according to claim 3, characterized in that: The trigger assembly further comprises an auxiliary sheet (21) fixedly connected to the second guide sheet (20); the inner side wall of the side cover (14) is fixedly connected to a support column (22); the auxiliary sheet (21) and the support column (22) are both fixedly connected to contacts, and the two contacts are arranged in close contact; the side cover (14) is rotatably connected to a third guide sheet (23); the side wall of the third guide sheet (23) is fixedly connected to a connecting sheet (24); the third guide sheet (23) is fixedly connected to a pressing spring (25); The end of the pressing spring (25) is fixedly connected to the side cover (14), an iron core (27) is fixedly connected to the side cover (14), a coil (26) is wound around the outer wall of the iron core (27), an iron plate (28) is arranged above the iron core (27), the iron plate (28) is fixedly connected to the third guide piece (23), the inner wall of the side cover (14) is fixedly connected to the fourth guide piece (29), and contacts are arranged at the ends of the third guide piece (23) and the fourth guide piece (29).
6. The silicon carbide diode sealed bridge rectifier module according to claim 5, characterized in that: The first guide piece (19), the second guide piece (20), the connecting piece (24) and the fourth guide piece (29) all extend to the outside of the housing (7).
7. The silicon carbide diode sealed bridge rectifier module according to claim 6, characterized in that: The heat dissipation assembly comprises a motor (31) fixedly connected to a side wall of a support plate (6); an output shaft of the motor (31) is fixedly connected to a rotating sleeve (32); an outer side wall of the rotating sleeve (32) is fixedly connected to blades (33); and the blades (33) are evenly distributed on the side wall of the rotating sleeve (32).
8. The silicon carbide diode sealed bridge rectifier module according to claim 7, characterized in that: The first guide piece (19) and the second guide piece (20) are connected between power lines of the motor (31), the contact on the auxiliary piece (21) and the contact on the support column (22) are connected between power lines of the coil (26), and the connecting piece (24) and the fourth guide piece (29) are connected between power lines of the module assembly.
9. The silicon carbide diode sealed bridge rectifier module according to claim 1, characterized in that: The module assembly comprises a stabilizing member (40) fixedly connected to the inner side wall of the module housing (1); a first contact piece (41), a second contact piece (42), a third contact piece (43) and a fourth contact piece (44) are fixedly connected to the stabilizing member (40); two connection points (45) are fixedly connected to the first contact piece (41); a semiconductor diode (46) and a connection point (45) are fixedly connected to the second contact piece (42) and the third contact piece (43); and two semiconductor diodes (46) are fixedly connected to the fourth contact piece (44).
10. The silicon carbide diode sealed bridge rectifier module according to claim 9, characterized in that: The semiconductor diode (46) is made of silicon carbide, and insulating heat-conducting silicone grease is filled between the first contact piece (41), the second contact piece (42), the third contact piece (43), the fourth contact piece (44) and the module cover plate (2).