A starter and its electromagnetic switch

Abstract

A starter and its electromagnetic switch, the starter comprises an electromagnetic switch, the electromagnetic switch comprises a shell, a support cover, a plunger core shaft, a stop seat, a winding assembly and a moving contact piece, the shell and the support cover are sealed and connected; the winding assembly, the stop seat and the plunger core shaft are installed in the shell; the end of the plunger core shaft passes through the stop seat and is connected to the moving contact piece, and drives the moving contact piece to move, a breathable structure is provided on the support cover, the breathable structure is arranged at the terminal hole of the support cover, and comprises a first step hole, a second step hole, a third step hole and a flow channel which are sequentially arranged in the terminal hole, and the flow channel is respectively connected to the third step hole and the inner cavity of the support cover; the terminal is a hollow breathable bolt, comprising a bolt bottom, a screw rod and a through hole which are connected to each other, and the through hole is coaxial with the bolt bottom and the screw rod; the screw rod is adapted to the first step hole, the bolt bottom is adapted to the second step hole, and a rotation-stopping structure is provided in the second step hole; a breathable membrane is provided in the second step hole and / or the third step hole.

Description

Technical Field

[0001] The utility model relates to a starter, in particular to a starter and an electromagnetic switch thereof. Background Art

[0002] The starter electromagnetic switch of the prior art has no ventilation device; or a hole is opened on the side of the support cover to add a one-way ventilation valve; or a hole is opened on the support cover, and a net is added to block debris, and a drainage function is added; there is also a pre-buried ventilation plug structure, but this structure has high requirements for the injection molding process and is prone to water ingress along the edge of the breathable membrane. There are also two holes opened on the electromagnetic switch support cover, each equipped with a ventilation plug. The ventilation plug needs to be installed through the hole in the support cover. The ventilation plug is close to the external environment and is easily affected by external debris, damaging the breathable membrane; and the ventilation plug may fall off into the inner cavity of the support cover after long-term use, and needs to be glued to prevent it from falling off. There is also a structure in which a perforation is added to the electromagnetic switch terminal block to connect the inner cavity and the outside, and the one-way ventilation valve protrudes from the terminal block, but this structure makes the terminal block difficult to fix and not compact, and it is easy to be damaged or fall off during assembly and transportation. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a starter and an electromagnetic switch thereof in view of the above-mentioned defects of the prior art, so as to solve the problems that the electromagnetic switch of the prior art needs to add air holes separately, resulting in a complicated structure and the air permeable membrane is easily damaged by foreign objects.

[0004] In order to achieve the above-mentioned purpose, the utility model provides an electromagnetic switch, including a shell, a support cover, a plunger core shaft, a stop seat, a winding assembly and a moving contact piece, wherein the shell and the support cover are sealed and connected; the winding assembly is installed in the shell; the stop seat is installed in the shell at one end close to the support cover; the plunger core shaft is installed in the shell corresponding to the winding assembly, the end of the plunger core shaft passes through the stop seat and is connected to the moving contact piece, and drives the moving contact piece to move, wherein the support cover is provided with a breathable structure, and the breathable structure is arranged at the terminal hole of the support cover, including A first step hole, a second step hole, a third step hole and a flow channel are sequentially arranged in the terminal hole, and the flow channel is respectively connected to the third step hole and the cavity of the support cover; the terminal is a hollow breathable bolt, including a bolt bottom, a screw rod and a through hole connected to each other, and the through hole penetrates the bolt bottom and the screw rod, and is coaxial with the bolt bottom and the screw rod; the screw rod is adapted to the first step hole, the bolt bottom is adapted to the second step hole, and a rotation-stopping structure for preventing the terminal from rotating is arranged in the second step hole; a breathable membrane is arranged in the second step hole and / or the third step hole.

[0005] In the above-mentioned electromagnetic switch, the air-permeable membrane is a bolt air-permeable membrane, which is arranged at the bottom of the bolt.

[0006] The above-mentioned electromagnetic switch, wherein the bolt breathable membrane is a stainless steel sintered metal wire mesh porous material membrane, a stainless steel fiber sintered filter felt membrane or an aluminum alloy / titanium alloy mesh material membrane, the bolt breathable membrane is welded or pasted on the plane of the bottom of the bolt, or embedded in the bottom of the bolt, and the size of a single breathable hole on the bolt breathable membrane is less than or equal to the diameter of a water molecule or a water vapor molecule.

[0007] The above-mentioned electromagnetic switch, wherein a breathable plug is arranged in the third step hole, and the breathable plug includes a plug body, and the diameter of the plug body is adapted to the inner diameter of the third step hole; a vent hole is arranged in the plug body, and the vent hole is respectively connected to the flow channel and the through hole; the breathable membrane is a plug body breathable membrane, and the plug body breathable membrane is arranged on the plug body corresponding to the vent hole.

[0008] In the above-mentioned electromagnetic switch, at least one retaining rib is arranged in the plug body, and the retaining rib is arranged around the inner wall of the vent hole.

[0009] In the above-mentioned electromagnetic switch, at least one sealing rib is arranged outside the plug body, and the sealing rib is arranged around the outer wall of the plug body.

[0010] In the above-mentioned electromagnetic switch, the plug body breathable membrane is a polytetrafluoroethylene material membrane or a textile material membrane, and the size of a single breathable hole on the plug body breathable membrane is less than or equal to the diameter of a water molecule or a water vapor molecule.

[0011] The above-mentioned electromagnetic switch, wherein the height of the plug body is less than or equal to the height of the third stepped hole, and when the height of the plug body is equal to the height of the third stepped hole, the plug body is provided with an opening corresponding to the flow channel, and the opening connects the flow channel and the vent hole.

[0012] In the above-mentioned electromagnetic switch, the bottom of the bolt is a polygonal prism, and the second stepped hole is a polygonal hole adapted to the polygonal prism.

[0013] In order to better achieve the above-mentioned purpose, the utility model also provides a starter, which includes the above-mentioned electromagnetic switch.

[0014] The technical effects of the utility model are:

[0015] The electromagnetic switch of the utility model adopts a ventilation structure in which the terminal is set as a hollow bolt structure, and a breathable membrane is set at the bottom of the hollow bolt; or a breathable plug is set in the terminal hole, and a breathable membrane is set on the breathable plug. While balancing the internal and external air pressures, it ensures a compact structure, is easy to assemble, and is conducive to better protecting the breathable membrane; in addition, the outer wall of the plug body of the breathable plug is provided with sealing ribs, and retaining ribs are provided in the vent hole, which can more effectively ensure the sealing of the plug body, keep the position of the plug body fixed, and prevent the plug body from deformation.

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but is not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the starter structure of an embodiment of the utility model;

[0018] Figure 2 A cross-sectional view of a starter according to an embodiment of the utility model;

[0019] Figure 3 This is a schematic diagram of the electromagnetic switch structure of an embodiment of the utility model;

[0020] Figure 4 A cross-sectional view of an electromagnetic switch according to an embodiment of the utility model;

[0021] Figure 5 This is a schematic diagram of the structure of a hollow breathable bolt according to an embodiment of the utility model;

[0022] Figure 6 This is a schematic diagram of a ventilation structure of an embodiment of the utility model;

[0023] Figure 7 This is a schematic diagram of the structure of a vent plug according to an embodiment of the utility model;

[0024] Figure 8 This is a schematic diagram of a ventilation structure of another embodiment of the utility model.

[0025] Among them, the reference numerals

[0026] 1Front cover

[0027] 2 Middle cover

[0028] 3 Back cover

[0029] 4 Solenoid switch

[0030] 41 Shell

[0031] 42 Support cover

[0032] 421 cover

[0033] 422 cavity

[0034] 423 breathable structure

[0035] 4231 terminal hole

[0036] 42311 First step hole

[0037] 42312 Second step hole

[0038] 42313 third step hole

[0039] 4232 terminal

[0040] 42321 Bolt bottom

[0041] 42322 screw

[0042] 42323 through hole

[0043] 42324 Bolt Breathable Membrane

[0044] 4233 breathable plug

[0045] 42331 plug body

[0046] 42332 Ventilation Hole

[0047] 42333 sealing rib

[0048] 42334 retaining tendons

[0049] 42335 plug body breathable membrane

[0050] 42336 Opening

[0051] 4234 runner

[0052] 424 50 terminal lugs

[0053] 425 winding wire hole

[0054] 426 30 terminal

[0055] 427 30B terminal

[0056] 43 plunger mandrel

[0057] 44 stop seat

[0058] 45 Winding components

[0059] 46 moving touch pieces

[0060] 47 Elastic reset element

[0061] 48 Insulation locking piece

[0062] 5. Stator

[0063] 6 Armature

[0064] 7 One-way device

[0065] 8 Fork

[0066] 9 Drive gear

[0067] 10 Relay DETAILED DESCRIPTION

[0068] The structural principle and working principle of the utility model are described in detail below in conjunction with the accompanying drawings:

[0069] See also Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the starter structure of an embodiment of the utility model. Figure 2 The figure is a cross-sectional view of a starter of an embodiment of the utility model. The starter of the utility model includes a front cover 1, a middle cover 2, a rear cover 3, an electromagnetic switch 4, a stator 5, an armature 6, a check valve 7, a shift fork 8 and a drive gear 9. The electromagnetic switch 4 is mounted on the middle cover 2 and fixed to the front cover 1 and the middle cover 2 by switch fastening bolts. There is a seal between the electromagnetic switch 4 and the middle cover 2 to ensure sealing. One end of the electromagnetic switch 4 is connected to the shift fork 8, and the shift fork 8 can be pulled to move. The 30 terminal 426 and the 50 terminal of the electromagnetic switch 4 are respectively connected to the corresponding terminals of the relay 10, and the connecting material is generally a wiring harness or a rigid / flexible conductive material; the 30B terminal 427 is connected to the stator 5 wiring harness. When the starter is installed on the engine, the 30 terminal 426 is connected to the positive electrode of the battery. The shift fork 8 is in the cavity of the front cover 1 and the middle cover 2, one end of which is connected to the electromagnetic switch 4, and the other end is connected to the check valve 7. The drive gear 9 is mounted on the check valve 7. There are sealing structures between the stator 5 and the rear cover 3 and the middle cover 2, and there are also sealing structures between the front cover 1 and the middle cover 2, and there are also sealing structures between the front cover 1 and the isolator 7. The entire internal space of the starter is connected, and it is a fully sealed starter. Although the entire starter is connected internally, within the spatial range of the situation, as the internal parts of the starter work, the air pressure may be higher or lower in a local area, so the electromagnetic switch 4 of the present application is provided with a breathable structure 423. Because the composition, structure, relative position relationship, connection relationship and function of other components of the starter are all relatively mature existing technologies, they will not be repeated here. The electromagnetic switch 4 of the present application, especially the breathable structure 423 of the electromagnetic switch 4, will be described in detail below.

[0070] See also Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the structure of an electromagnetic switch 4 according to an embodiment of the utility model. Figure 4The electromagnetic switch 4 of the utility model is a cross-sectional view of an embodiment of the utility model. The electromagnetic switch 4 of the utility model includes a housing 41, a support cover 42, a plunger core shaft 43, a stopper 44, a winding assembly 45, a movable contact piece 46 and an elastic reset member 47. The housing 41 and the support cover 42 are sealed and connected; the winding assembly 45 is installed in the housing 41; the stopper 44 is installed in the housing 41 near one end of the support cover 42; the plunger core shaft 43 is installed in the housing 41 corresponding to the winding assembly 45. The end of the plunger core shaft 43 passes through the stop seat 44 and is connected to the movable contact piece 46, and drives the movable contact piece 46 to move; the stop seat 44 is installed in the winding assembly 45 and the electromagnetic switch 4 housing 41, and the stop seat 44 is in a fixed state and will not be displaced, and has the function of stopping the plunger core shaft 43; the winding assembly 45 is composed of a coil, which can generate a magnetic field and pull the plunger core shaft 43 to move, and the coil end of the winding assembly 45 passes through the winding wire hole 4 on the support cover 42 25, and fixed outside the winding wire hole 425, the fixing method is generally welding; the elastic reset member 47 is respectively arranged between the plunger core shaft 43 and the stop seat 44 and between the plunger core shaft 43 and the movable contact piece 46, and the elastic reset member 47 is installed on the plunger core shaft 43 and the stop seat 44, and can be compressed by the plunger core shaft 43 and can push the plunger core shaft 43 back; another elastic reset member is installed on the plunger core shaft 43, and the other end is pressed against the insulating locking member 48; the movable contact piece 46 is installed on the plunger core shaft 43 The movable contact piece 46 can move with the movement of the plunger core shaft 43. When the movable contact piece 46 moves to the rightmost side, the 30 terminal 426 and the 30B terminal 427 are connected. When the starter is powered off, the movable contact piece 46 is reset under the action of another elastic reset piece, and the 30 terminal 426 and the 30B terminal 427 are disengaged. The support cover 42 is installed on the stop seat 44 by means of a combination screw, and a sealing gasket is provided in the middle for sealing.

[0071] During operation, when the 50 terminal is energized, the current passes through the 50 terminal connecting piece 424 to the winding assembly 45 in sequence, and the winding assembly 45 generates a magnetic field, pulling the plunger core shaft 43 to move to the right, and the moving contact piece 46 will move with the movement of the plunger core shaft 43, and the elastic reset piece 47 is compressed at this time. When the moving contact piece 46 moves to the end surface of the 30 terminal 426 and the 30B terminal 427, the 30 terminal 426 and the 30B terminal 427 will be connected, so that the stator 5 is energized, the stator 5 generates a magnetic field, and the armature 6 rotates, and the armature 6 drives the isolator 7 and the driving gear 9 to rotate, thereby starting the engine. When the 50 terminal is de-energized, the elastic reset piece 47 is in a compressed state. Under the action of the spring force, the plunger core shaft 43 moves to the right, and the moving contact piece 46 moves with the movement of the plunger core shaft 43, so that the 30 terminal 426 and the 30B terminal 427 are disconnected, the stator 5 is de-energized, and the starter stops rotating.

[0072] The cover body 421 of the support cover 42 is provided with a breathable structure 423, and the breathable structure 423 is arranged at the terminal hole 4231 of the support cover 42, including a first step hole 42311, a second step hole 42312, a third step hole 42313 and a flow channel 4234 sequentially arranged in the terminal hole 4231, and the flow channel 4234 is respectively connected with the third step hole 42313 and the cavity 422 of the support cover 42; the terminal 4232 is preferably a hollow breathable bolt, including a bolt bottom 42321, a screw bottom 42322 and a screw bottom 42323 connected to each other. Rod 42322 and through hole 42323, the through hole 42323 passes through the bolt bottom 42321 and the screw rod 42322, and is coaxial with the bolt bottom 42321 and the screw rod 42322; the screw rod 42322 is adapted to the first stepped hole 42311, the bolt bottom 42321 is adapted to the second stepped hole 42312, and the second stepped hole 42312 is provided with a rotation-stopping structure for preventing the terminal 4232 from rotating; a breathable membrane is provided in the second stepped hole 42312 and / or the third stepped hole 42313.

[0073] See also Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the structure of a hollow breathable bolt according to an embodiment of the utility model. Figure 6Schematic diagram of the ventilation structure 423 of an embodiment of the utility model. This embodiment is described by taking the ventilation structure 423 arranged at the 50 terminal hole 4231 as an example. The 50 terminal hole 4231 and the winding wire hole 425 are arranged symmetrically to the axis of the support cover 42. The winding wire hole 425 is a hole for the end of the wire of the winding assembly 45 to extend out, and the wire passes through the winding wire hole 425. The ventilation membrane is a bolt ventilation membrane 42324, which is arranged on the plane of the bottom 42321 of the bolt. The screw 42322 of the hollow ventilation bolt passes through the first stepped hole 42311, and the 50 terminal terminal piece 424 and the support cover 42 are fixed by nuts and washers. The diameter of the screw rod 42322 is smaller than the first stepped hole 42311, the bolt bottom 42321 matches the second stepped hole 42312, the second stepped hole 42312 has a rotation-stopping structure, and the second stepped hole 42312 can be a polygonal or special-shaped structure. The bolt bottom 42321 is preferably a polygonal prism, and the second stepped hole 42312 is a polygonal hole adapted to the polygonal prism, preferably a quadrilateral or hexagonal shape for the easiest implementation, and the rotation-stopping structure is the edge of the polygonal hole. The shape of the bolt bottom 42321 is consistent with the shape of the second stepped hole 42312, and the size is slightly smaller than the second stepped hole 42312, and the assembly and rotation-stopping requirements are met. The hollow breathable bolt can also be directly embedded in the support cover 42, and the diameter of the screw rod 42322 is equal to the diameter of the first stepped hole 42311.

[0074] The vent structure 423 can also be set at the 30 terminal hole or the 30B terminal hole. When the vent structure 423 is set at the hole of the 30 terminal 426 or the 30B terminal 427, it is similar to being set at the 50 terminal hole 4231. When it is set at the hole of the 30 terminal 426 or the 30B terminal 427, the corresponding 30 terminal 426 and 30B terminal 427 are hollow bolt structures, and a bolt vent membrane 423 is set at the bottom of the bolt of the 30 terminal 426 and the 30B terminal 427. 24. The 30 terminal 426 and the 30B terminal 427 are fastened to the support cover 42 and a seal is provided between the support cover 42. The end faces of the 30 terminal 426 and the 30B terminal 427 are flush; one end of the motor terminal lug is fastened to the 30B terminal 427, and the other end is connected to the end of the wire of the winding assembly 45, preferably welded to the support cover 42; one end of the 50 terminal lug 424 is fastened to the 50 terminal, and the other end is connected to the other end of the wire of the winding assembly 45. The bolt breathable membrane 42324 is preferably a stainless steel sintered metal wire mesh porous material membrane, a stainless steel fiber sintered filter felt membrane or an aluminum alloy / titanium alloy mesh material membrane, etc., which is arranged at the bottom 42321 of the bolt, and can be welded or pasted on the plane of the bottom 42321 of the bolt, or embedded in the bottom 42321 of the bolt. The size of a single breathable hole on the bolt breathable membrane 42324 is less than or equal to the diameter of a water molecule or a water vapor molecule, and is only breathable but not water-permeable.

[0075] When the 50 terminal of the electromagnetic switch 4 is energized, the current generates a magnetic field under the action of the winding assembly 45, pulling the plunger core shaft 43 to move rightward, the internal space of the cavity 422 of the electromagnetic switch 4 is reduced, and the air pressure in the cavity 422 increases instantly. The gas is discharged from the electromagnetic switch 4 through the flow channel 4234, the third step hole 42313, the second step hole 42312, the bolt breathable membrane 42324, and the through hole 42323 in sequence, thereby balancing the internal and external air pressures of the electromagnetic switch 4. When the external air pressure is greater than the air pressure of the cavity 422 of the electromagnetic switch 4, the gas enters the cavity 422 in the opposite direction.

[0076] See also Figure 7 , Figure 7 The figure is a schematic diagram of the structure of the air plug 4233 of an embodiment of the utility model. The air plug 4233 is arranged in the third stepped hole 42313 of the embodiment, and the air plug 4233 comprises a plug body 42331, and the diameter of the plug body 42331 matches the inner diameter of the third stepped hole 42313; the plug body 42331 is provided with an air hole 42332, and the air hole 42332 is connected with the flow channel 4234 and the through hole 42323 respectively; the air permeable membrane is a plug body air permeable membrane 42335, and the plug body air permeable membrane 42335 is arranged on the plug body 42331 corresponding to the air hole 42332, and is preferably arranged at the top of the plug body 42331. Among them, at least one retaining rib 42334 is arranged in the plug body 42331, and the retaining rib 42334 is arranged around the inner wall of the air hole 42332. At least one sealing rib 42333 is arranged outside the plug body 42331, and the sealing rib 42333 is arranged around the outer wall of the plug body 42331. The retaining rib 42334 can allow the plug body 42331 to maintain its shape before compression to the maximum extent, so that the sealing rib 42333 is evenly stressed and firmly in an extruded deformation state for a long time, thereby ensuring sealing and preventing movement. The plug body breathable membrane 42335 is preferably a polytetrafluoroethylene material membrane or a textile material membrane, and the size of a single breathable hole on the plug body breathable membrane 42335 is less than or equal to the diameter of a water molecule or a water vapor molecule, and is only breathable but not water-permeable.

[0077] See also Figure 8 , Figure 8 The figure is a schematic diagram of a breathable structure 423 of another embodiment of the utility model. The breathable plug 4233 fits the third step hole 42313, and the sealing rib 42333 is larger than the diameter of the third step hole 42313. The sealing rib 42333 is squeezed and deformed to achieve sealing. At the same time, the breathable plug 4233 is prevented from moving in the third step hole 42313 due to the squeeze deformation. The retaining rib 42334 can allow the plug body 42331 to maintain its shape before compression to the greatest extent possible, so that the sealing rib 42333 is evenly stressed and is firmly in an squeeze deformation state for a long time, thereby ensuring sealing and preventing movement. In this embodiment, the height of the plug body 42331 is less than (e.g. Figure 4 as shown) or equal to the height of the third stepped hole 42313 (as shown Figure 8 See Figure 4 When the height of the plug body 42331 is less than the height of the third stepped hole 42313, when the electromagnetic switch 4 is attracted or heated, the air pressure in the cavity 422 increases, and the internal gas passes through the flow channel 4234, the third stepped hole 42313, the vent hole 42332, the plug body breathable membrane 42335, the second stepped hole 42312, and the through hole 42323 in sequence, and is discharged from the electromagnetic switch 4; when the external air pressure is greater than the air pressure of the cavity 422 of the electromagnetic switch 4, the gas enters the cavity 422 in the opposite direction. Alternatively, when the starter or the electromagnetic switch 4 is heated, the gas passes through the flow channel 4234, the third stepped hole 42313, the vent hole 42332, the plug body breathable membrane 42335, the second stepped hole 42312, the bolt breathable membrane 42324, and the through hole 42323 in sequence, and is discharged from the electromagnetic switch 4. When the external air pressure is greater than the air pressure in the cavity 422 of the electromagnetic switch 4, the gas enters the cavity 422 in the opposite direction, thereby balancing the internal and external air pressures of the electromagnetic switch 4. Since the electromagnetic switch 4 is connected to other parts inside the starter, the internal pressure of the starter can be balanced with the external air pressure after a long time.

[0078] See also Figure 8 , when the height of the plug body 42331 is equal to the height of the third stepped hole 42313, the plug body 42331 is provided with an opening 42336 corresponding to the flow channel 4234, and the opening 42336 connects the flow channel 4234 and the vent hole 42332. When the height of the plug body 42331 is equal to the height of the third stepped hole 42313, the upper end of the vent plug 4233 is in contact with the upper end of the third stepped hole 42313, and the lower end is flush with the bottom surface of the support cover 42. After the electromagnetic switch 4 is assembled, the bottom is supported by the body, the plunger assembly and the sealing gasket to prevent displacement. When the air pressure in the cavity 422 increases, the gas is discharged from the electromagnetic switch 4 through the flow channel 4234, the opening 42336, the vent hole 42332, the plug body vent membrane 42335, the second stepped hole 42312, and the through hole 42323 in sequence.

[0079] The electromagnetic switch 4 of the utility model has a compact structure, is easy to assemble, and has higher reliability. It adopts a hollow bolt structure, and a breathable plug 4233 is arranged at the lower part of the bolt. The terminal hollow bolt is used for ventilation to balance the internal and external air pressures. The breathable membrane is arranged in the support cover 42, which is easy to assemble and not easy to fall off, and has a good protection effect on the breathable membrane; retaining ribs 42334 and sealing ribs 42333 are added to the breathable plug 4233, which can more effectively ensure sealing and prevent displacement, and keep the plug body 42331 in a fixed position; the disadvantage of easy damage of the structure caused by the need to increase the hole of the breathable plug 4233 is effectively avoided.

[0080] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field can make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. An electromagnetic switch, comprising a housing, a support cover, a plunger core shaft, a stopper, a winding assembly and a moving contact piece, wherein the housing and the support cover are sealed and connected; the winding assembly is installed in the housing; the stopper is installed in the housing at one end close to the support cover; the plunger core shaft is installed in the housing corresponding to the winding assembly, the end of the plunger core shaft passes through the stopper and is connected to the moving contact piece, and drives the moving contact piece to move, characterized in that: The support cover is provided with a breathable structure, which is arranged at the terminal hole of the support cover, and includes a first step hole, a second step hole, a third step hole and a flow channel which are sequentially arranged in the terminal hole, and the flow channel is respectively connected with the third step hole and the cavity of the support cover; the terminal is a hollow breathable bolt, including a bolt bottom, a screw rod and a through hole which are connected to each other, and the through hole passes through the bolt bottom and the screw rod, and is coaxial with the bolt bottom and the screw rod; the screw rod is adapted to the first step hole, and the bolt bottom is adapted to the second step hole, and a rotation-stopping structure for preventing the terminal from rotating is arranged in the second step hole; a breathable membrane is arranged in the second step hole and / or the third step hole.

2. The electromagnetic switch according to claim 1, characterized in that: The breathable membrane is a bolt breathable membrane, which is arranged at the bottom of the bolt.

3. The electromagnetic switch according to claim 2, characterized in that: The bolt breathable membrane is a stainless steel sintered metal wire mesh porous material membrane, a stainless steel fiber sintered filter felt membrane or an aluminum alloy / titanium alloy mesh material membrane. The bolt breathable membrane is welded or pasted on the plane of the bottom of the bolt, or embedded in the bottom of the bolt. The size of a single breathable hole on the bolt breathable membrane is less than or equal to the diameter of a water molecule or a water vapor molecule.

4. The electromagnetic switch according to claim 1, characterized in that: A breathable plug is arranged in the third stepped hole, and the breathable plug includes a plug body, and the diameter of the plug body is adapted to the inner diameter of the third stepped hole; a vent hole is arranged in the plug body, and the vent hole is connected with the flow channel and the through hole respectively; the breathable membrane is a plug body breathable membrane, and the plug body breathable membrane is arranged on the plug body corresponding to the vent hole.

5. The electromagnetic switch according to claim 4, characterized in that: At least one retaining rib is disposed in the plug body, and the retaining rib is disposed around the inner wall of the vent hole.

6. The electromagnetic switch according to claim 4, characterized in that: At least one sealing rib is arranged outside the plug body, and the sealing rib is arranged around the outer wall of the plug body.

7. The electromagnetic switch according to claim 4, characterized in that: The plug body breathable membrane is a polytetrafluoroethylene material membrane or a textile material membrane, and the size of a single breathable hole on the plug body breathable membrane is smaller than or equal to the diameter of a water molecule or a water vapor molecule.

8. The electromagnetic switch according to claim 4, characterized in that: The height of the plug body is less than or equal to the height of the third stepped hole. When the height of the plug body is equal to the height of the third stepped hole, the plug body is provided with an opening corresponding to the flow channel, and the opening connects the flow channel and the vent hole.

9. The electromagnetic switch according to claim 1, characterized in that: The bottom of the bolt is a polygonal prism, and the second stepped hole is a polygonal hole adapted to the polygonal prism.

10. A starter, characterized in that: The electromagnetic switch comprises the electromagnetic switch as claimed in any one of claims 1 to 9.

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