JP6175986B2 - Electromagnetic switch for starter - Google Patents

Description

  The present invention relates to an electromagnetic switch used in a reduction type starter.

Conventionally, a reduction type starter 100 shown in FIG. 5 is known. FIG. 5 is a plan view of FIG. 1 of Patent Document 1 viewed from the upper side (end side in the axial direction). In this reduction type starter 100, an armature shaft of a motor 110 and a pinion shaft having a pinion on the shaft are arranged in parallel via a reduction gear, and an electromagnetic switch 120 is arranged on a coaxial line with the pinion shaft. Composed. The electromagnetic switch 120 pushes the pinion shaft forward (on the ring gear side of the engine) by the operation of the solenoid and has a function of opening and closing a main contact for turning on / off the energization current of the motor 110.
The electromagnetic switch 120 has a center case that forms an outer frame of the solenoid, and the cross-sectional shape orthogonal to the axial direction of the center case is formed in a substantially pentagonal shape. A metal end cover 130 is fixed to the rear side opening end of the center case with a screw 140 via a gasket. The end cover 130 has a substantially pentagonal planar shape corresponding to the cross-sectional shape of the center case, and is fixed to the center case with screws 140 at three corners among the five corners. It is equidistant from the center position of the center case to the three screw fixing portions.

JP 2006-9681 A

By the way, in the above electromagnetic switch, when energization to the coil is stopped and the attractive force of the electromagnet disappears, the plunger is pushed back by the reaction force of the return spring. The return position of the plunger is regulated by a resin insulator that insulates and holds the movable contact with the plunger abutting against a tapered portion provided at the center position of the end cover. For this reason, when the electromagnetic switch is turned off, that is, when energization to the coil is stopped and the plunger is pushed back, a loud contact noise is generated when the insulator contacts the end cover. In particular, in a vehicle equipped with an idling stop, the number of actuations of the electromagnetic switch is greatly increased, so that it is desired to reduce the contact noise generated when the plunger returns.
The gasket inserted between the center case and the end cover is substantially pentagonal like the cross-sectional shape of the center case, but the end cover is fixed with three screws, Screw tightening force is not evenly applied. For this reason, the pressure distribution of the gasket is not uniform, and there is a concern about ensuring a stable sealing state.

Furthermore, in the starter, there is a demand for mounting a diode for absorbing a surge voltage, a capacitor for noise suppression, a means for suppressing an inrush current to the motor (referred to as an ICR relay), and the like. In this case, it is desired to incorporate electronic components such as diodes and capacitors and an electronic circuit board for controlling the operation time of the ICR relay in the electromagnetic switch. However, in the electromagnetic switch used in the conventional reduction type starter, a space for arranging electronic components, an electronic circuit board, and the like cannot be secured, so that the electromagnetic switch must be externally mounted.
The present invention has been made on the basis of the above circumstances, and its object is to reduce the contact noise generated when the plunger returns, and to provide an arrangement space for electronic components, electronic circuit boards, etc. in the center case. An object is to provide an electromagnetic switch for a starter that can be secured.

An electromagnetic switch for a starter according to claim 1 includes a set of fixed contacts connected to a motor energization circuit, a movable contact that electrically opens and closes the set of fixed contacts, and a set of the movable contacts. A solenoid that is driven in the axial direction facing the fixed contact.
The solenoid consists of a coil that forms an electromagnet when energized, a plunger that is attracted by the electromagnet and moves to one side in the axial direction, and a plunger that pushes the plunger back when the energizing force of the electromagnet disappears when the energization of the coil stops A return spring, a resin insulator that holds the movable contact with the plunger, a cylindrical center case that forms the outer frame of the solenoid, and a metal that closes the opening end of the center case that opens to the other side in the axial direction The end cover is fastened to the center case with a plurality of screws, and when the electromagnet's attractive force disappears and the plunger is pushed back by the return spring, the insulator is in contact with the end cover. This restricts the return position of the plunger.
In the electromagnetic switch, the center case is provided in a polygon having a cross section perpendicular to the axial direction and having six corners , and the end cover has six corners corresponding to the cross section of the center case. The four corners of the six corners are fixed to the center case by screws, and the place where the end cover is fixed to the center case with screws is called the screw fixing part . Of the screw fixing portions, three screw fixing portions are provided at equidistant positions from the axial center of the solenoid, and the remaining one screw fixing portion extends from the axial center of the solenoid to the three screw fixing portions. It is set at a position farther than the distance .

According to the configuration of the present invention, those Se'on from abutment near the screw fixing portion is set at a position farther than the distance from the axial center of the solenoid to the screw fixing portion of the three locations, screw fixing of three A sound lower than the contact sound from the contact part close to the part is generated. In other words, when the end cover is modeled as an aggregate of a plurality of bands extending radially from the center, the longer the band, the longer the period of vibration that occurs when the insulator abuts, and hence the lower the sound. . Therefore, when the attracting force of the electromagnet disappears and the plunger is pushed back by the reaction force of the return spring, the frequency distribution of the contact sound that hits the entire contact surface of the end cover, which is an aggregate of bands, varies. The sound pressure is reduced and the sound can be made quieter.

In addition, of the screw fixing portion of 4箇plants, screw fixing portions of 1箇plants, because it is set at a position farther than the distance from the axial center of the solenoid to the screw fixing portion of the three, the internal space of the center case Can be expanded. As a result, electronic components such as diodes and capacitors, or electronic circuit boards can be built in the electromagnetic switch.
Further, 1 the screw fixing portion of箇plants by setting farther from the shaft center of the solenoid, it is corners overhanging outward to the outer shape of the center case where the screw fixing portion is set. As a result, when the starter is assembled to the engine, it is easy to place a hand on the corner portion that protrudes to the outside of the center case, and the shape can be easily held, thereby improving workability.

1 is a half sectional view of a reduction type starter according to Embodiment 1. FIG. It is the top view which looked at the reduction type starter concerning Example 1 from the non-pinion side of the axial direction. 1 is a half cross-sectional view of an electromagnetic switch according to Embodiment 1. FIG. It is a top view which shows arrangement | positioning of the end cover of the electromagnetic switch which concerns on Example 1, and the screw which fixes the end cover. It is the top view which looked at the reduction type starter which concerns on a prior art from the non-pinion side of the axial direction.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

[Example 1]
In Example 1, an example in which the electromagnetic switch of the present invention is applied to a reduction type starter will be described.
As shown in FIG. 1, the reduction type starter 1 includes a motor 2 that generates a rotational force, a pinion shaft 3 that is arranged in parallel with an armature shaft 2 a of the motor 2, and a shaft supported by the pinion shaft 3. The pinion 4 that rotates integrally with the pinion shaft 3, a speed reduction mechanism (described later) that decelerates the rotational speed of the motor 2 and amplifies the motor torque, and the motor torque amplified by this speed reduction mechanism is applied to the pinion shaft 3. It comprises a clutch 5 for transmission and an electromagnetic switch 6 of the present invention disposed on the same axis as the pinion shaft 3.

Hereinafter, in the axial direction of the starter 1 shown in FIG. 1 (the horizontal direction in the figure), the left side in the figure is defined as the front side and the right side in the figure is defined as the rear side.
The motor 2 includes an electromagnet field (described below) that forms a magnetic field, an armature 8 including a commutator 7 on the rear side of the armature shaft 2a, a brush 9 disposed on the outer periphery of the commutator 7, and the like. This is a well-known commutator motor constructed from the above.
The electromagnet field is composed of a field magnetic pole 12 fixed by a screw 11 on the inner periphery of a yoke 10 forming a magnetic circuit, and a field coil 13 in which a rectangular wire is wound around the field magnetic pole 12. The Instead of the electromagnet field, a permanent magnet field in which a permanent magnet is disposed on the inner periphery of the yoke 10 can be employed.

The pinion shaft 3 is inserted into the inner periphery of the spline tube 14 by helical spline fitting, and is urged to the right direction in the drawing by the return spring 15 with respect to the spline tube 14.
The front end of the spline tube 14 is rotatably supported by a starter housing 17 via a ball bearing 16, and the rear end is rotatably supported by a center housing 19 via a ball bearing 18. .
The pinion 4 is arranged by direct spline fitting on the outer periphery of the pinion shaft 3 protruding from the front side end surface of the spline tube 14, and is pressed against the front side end surface of the spline tube 14 by the pinion spring 20.

The speed reduction mechanism is configured by a gear train including a drive gear 21 formed at the front side end of the armature shaft 2 a, an idle gear 22 that meshes with the drive gear 21, and a clutch gear 23 that meshes with the idle gear 22. .
The idle gear 22 is rotatably supported on the outer periphery of the gear shaft 22a. The rear end of the gear shaft 22a is press-fitted and fixed in a fitting hole formed in the center housing 19, and the front end is inserted into a fitting hole formed in the starter housing 17 and supported.
The clutch gear 23 is assembled by spline fitting to the outer periphery of a cylindrical boss portion 23a, and the boss portion 23a is supported on the outer periphery of the spline tube 14 via a bearing 24 so as to be relatively rotatable.
The clutch 5 is, for example, a roller type one-way clutch, and transmits the motor torque transmitted through the speed reduction mechanism to the spline tube 14.

Next, the configuration of the electromagnetic switch 6 according to the present invention will be described.
As shown in FIG. 1, the electromagnetic switch 6 pushes the pinion shaft 3 to the left in the drawing by using the attractive force of the electromagnet, and has a main contact (described later) for turning on / off the energization current of the motor 2. It has a solenoid SL that opens and closes.
As shown in FIG. 3, the solenoid SL includes a coil 25 that forms an electromagnet when energized, a plunger 26 that moves in the axial direction on the inner periphery of the coil 25, and a fixed iron core 27 that is magnetized by the electromagnet and attracts the plunger 26. And a switch frame (to be described later) that accommodates these components.
The coil 25 is configured by winding an insulation-coated copper wire around a resin bobbin 28.
A cylindrical sleeve 29 that guides the movement of the plunger 26 is inserted into the inner periphery of the bobbin 28.

The plunger 26 has a plunger sliding portion 26a that moves in the axial direction on the inner periphery of the sleeve 29, and a plunger extending portion 26b that extends to the rear side from the plunger sliding portion 26a. The plunger sliding portion 26a The outer diameter of the plunger extending portion 26b is formed smaller than the outer diameter. That is, a step is formed between the plunger sliding portion 26a and the plunger extending portion 26b. The plunger 26 is formed with a hollow hole that penetrates the central portion in the radial direction in the axial direction, and a stepped portion 26 c that protrudes toward the inner diameter side is formed in the middle of the hollow hole.
The fixed iron core 27 is connected to an annular core plate 30 that forms a part of the magnetic circuit, and is disposed on the front inner periphery of the coil 25. The core plate 30 is disposed adjacent to the front side end face of the coil 25 and magnetically connects a stationary core (not shown) that forms a magnetic path in the axial direction and the fixed iron core 27.

As shown in FIG. 3, a plunger rod 31 for transmitting the movement of the plunger 26 that is attracted and moved by the electromagnet to the pinion shaft 3 is inserted into the hollow hole of the plunger 26. The plunger rod 31 is provided with a flange portion 31 a at an end portion on the rear side, and the flange portion 31 a is disposed in a hollow hole on the rear side from a stepped portion 26 c formed on the plunger 26. The outer diameter of the flange portion 31a is formed larger than the inner diameter of the stepped portion 26c.
A drive spring 32 for pushing the pinion 4 when the pinion 4 meshes with an engine ring gear (not shown) is disposed in the hollow hole on the rear side of the stepped portion 26c of the plunger 26. The drive spring 32 is supported by an end on the front side coming into contact with the flange portion 31a of the plunger rod 31 and an end on the rear side coming into contact with an end plate 33 fixed to the end surface of the plunger extension portion 26b. Yes.
On the outer periphery of the plunger rod 31 extending from the stepped portion 26c of the plunger 26 to the front side, a return spring 34 for pushing the plunger 26 back in the anti-fixed iron core direction (right direction in the drawing) is arranged when the attraction force of the electromagnet disappears. Established.

The main contact is a pair of fixed contacts (not shown) connected to the energization circuit of the motor 2 via the two bolt terminals 35 and 36 (see FIG. 2), and an electrical connection between the set of fixed contacts. And a movable contact 37 (see FIG. 3) that opens and closes automatically.
The two bolt terminals 35 and 36 are fixed to a center case 38 which will be described later, and as shown in FIG. 2, the remaining one screw fixing portion in the radial direction (left-right direction in the drawing) orthogonal to the axial direction of the electromagnetic switch 6. Is taken out in opposition to the position set farther from the distance from the axial center of the solenoid to the three screw fixing portions.
The pair of fixed contacts are disposed in the center case 38 so as to face each other in the radial direction of the plunger sliding portion 26a. As shown in FIG. 3, the movable contact 37 is sandwiched between a resin insulating plate 39 and an insulator 40 and held on the outer periphery of the plunger extension 26b, and the contact pressure is applied when the main contact is closed. It is urged by the contact pressure spring 41 for applying.
The contact pressure spring 41 is disposed on the outer periphery of the plunger extension 26 b, the front end is supported by the insulator 40, and the rear end is supported by the outer end of the end plate 33.

The switch frame includes the above-described center case 38 and a metal end cover 42 that closes the rear side opening end of the center case 38.
As shown in FIG. 1, the center case 38 is provided integrally with the center housing 19 and extends from the center housing 19 to the rear side in a cylindrical shape.
The end cover 42 is assembled with a gasket 43 sandwiched between the rear opening end of the center case 38 and is fastened and fixed to the center case 38 by a plurality of screws 44. As shown in FIG. 3, the end cover 42 is provided with a bottomed cylindrical portion 42a that covers the outer periphery of the plunger extending portion 26b and protrudes in a cylindrical shape, and is on the opposite bottom side of the bottomed cylindrical portion 42a. The root side is formed to be tapered. Hereinafter, the base side of the bottomed cylindrical portion 42 a formed in a tapered shape is referred to as a tapered surface of the end cover 42.

  The tapered surface of the end cover 42 has a function as a stopper surface that regulates the return position of the plunger 26. That is, when the energization of the coil 25 is stopped and the attraction force of the electromagnet disappears, when the plunger 26 is pushed back by the reaction force of the return spring 34, the insulator 40 comes into contact with the taper surface of the end cover 42, whereby the plunger 26 Stops moving. In addition, a tapered surface is formed on the outer periphery of the insulator 40 so that it can come into surface contact with the tapered surface of the end cover 42 all around when contacting the tapered surface of the end cover 42 (see FIG. 3). Therefore, the position where the plunger 26 is pushed back and stopped by the reaction force of the return spring 34 is restricted by the taper surface formed on the insulator 40 abutting the taper surface provided on the end cover 42.

The center case 38 according to the present invention is provided in a substantially hexagonal shape in which the cross-sectional shape orthogonal to the axial direction of the electromagnetic switch 6 has six corners. Further, as shown in FIGS. 2 and 4, the end cover 42 has a substantially hexagonal shape in which the planar shape viewed from the axial direction has six corners corresponding to the cross-sectional shape of the center case 38. Four corners out of the six corners are fixed to the center case 38 by screws 44, respectively.
Here, a portion where the end cover 42 is fixed to the center case 38 with a screw 44 is referred to as a screw fixing portion, and of the four screw fixing portions shown in FIG. , The second screw fixing portion, the third screw fixing portion, and the fourth screw fixing portion.

In the end cover 42 shown in FIG. 4, the first screw fixing portion and the second screw fixing portion are disposed at positions symmetrical with respect to the symmetry axis YY passing through the axial center O of the solenoid SL. Similarly, the second screw fixing portion and the third screw fixing portion are disposed at positions that are vertically symmetrical with respect to the symmetry axis XX passing through the axial center O of the solenoid SL. That is, the first screw fixing portion to the third screw fixing portion are arranged at a position equidistant from the axial center O of the solenoid SL.
On the other hand, the fourth screw fixing portion is disposed at an asymmetric position with respect to the first screw fixing portion to the third screw fixing portion, and the first screw fixing portion to the third screw from the axial center O of the solenoid SL. It is set at a position farther than the distance to the fixed part.

Next, the operation of the reduction starter 1 will be described.
Here, an operation when an engine restart request is generated after idling stop has been performed and the engine has been automatically stopped will be described.
The engine restart request is determined by an idling stop ECU (not shown) based on a start operation (for example, a brake release operation, a shift operation to a drive range, etc.) by the user.
The ECU closes a starter relay (not shown) in response to the restart request. When the starter relay is closed, the coil 25 is energized from the battery to activate the solenoid SL. Specifically, an electromagnet is formed by energizing the coil 25, and the plunger 26 is attracted to the magnetized fixed iron core 27 and moves in the axial direction. As the plunger 26 moves, the pinion shaft 3 is pushed forward (leftward in FIG. 1) through the plunger rod 31, and the pinion 4 supported by the pinion shaft 3 comes into contact with the ring gear.

  After the pinion 4 comes into contact with the ring gear, the plunger 26 further moves while the drive spring 32 is bent, and the movable contact 37 comes into contact with a set of fixed contacts and is urged by the contact pressure spring 41, thereby causing the main contact. Is closed. As a result, electric power is supplied from the battery to the motor 2, and a rotational force is generated in the armature 8. The rotational force is transmitted to the pinion shaft 3 through the speed reduction mechanism, and the pinion shaft 3 rotates. When the pinion shaft 3 rotates to a position where the pinion 4 can mesh with the ring gear, the reaction force stored in the drive spring 32 pushes the pinion 4 into the ring gear, thereby completing the meshing of the pinion 4 and the ring gear. As a result, the motor torque amplified by the speed reduction mechanism is transmitted from the pinion 4 to the ring gear to crank the engine.

After the engine is started, the starter relay is controlled to open by the ECU. When the energization of the coil 25 is stopped and the attractive force of the electromagnet disappears, the plunger 26 is pushed back toward the anti-fixed iron core by the reaction force of the return spring 34. As the plunger 26 moves, the pinion shaft 3 is pushed back to the return spring 20, the meshing between the pinion 4 and the ring gear is released, the main contact is opened, and the motor 2 is de-energized to turn off the motor. The rotation of 2 gradually decelerates and stops.
In addition, the plunger 26 pushed back in the anti-fixed iron core direction has its return position regulated by the taper surface of the insulator 40 holding the movable contact 37 coming into contact with the taper surface of the end cover 42.

[Operation and Effect of Example 1]
The end cover 42 of the electromagnetic switch 6 according to the first embodiment is provided in a substantially hexagonal shape in which the planar shape viewed from the axial direction has six corners, and four corners among the six corners. It is fixed to the center case 38 by screws 44. That is, it is fixed to the center case 38 by the four screws 44. In addition, among the four screw fixing portions shown in FIG. 4, the first screw fixing portion to the third screw fixing portion are arranged at an equal distance from the axial center O of the solenoid SL, whereas the fourth screw fixing portion is the fourth screw fixing portion. The fixing portion is disposed at an asymmetric position with respect to the first screw fixing portion to the third screw fixing portion, and is farther than the distance from the axial center O of the solenoid SL to the first screw fixing portion to the third screw fixing portion. Set to position.

  According to said structure, when the plunger 26 is pushed back and the insulator 40 contact | abuts to the end cover 42, the contact sound from the contact part near a 4th screw fixing part is the 1st screw fixing | fixed part-3rd. A sound lower than the contact sound from the contact part close to the screw fixing part is generated. In other words, when the end cover 42 is modeled as an aggregate of a plurality of bands extending radially from the center thereof, the longer the band, the longer the period of vibration generated when the insulator 40 abuts, and thus a lower sound. Occur. Therefore, when the attracting force of the electromagnet disappears and the plunger 26 is pushed back by the reaction force of the return spring 34, the frequency distribution of the contact sound where the insulator 40 hits the entire contact surface of the end cover 42 which is an assembly of bands As a result, the sound pressure is reduced and the sound can be made quieter.

  Further, by setting the fourth screw fixing portion at a position far from the axial center O of the solenoid SL, the internal space of the center case 38 can be expanded as compared with the conventional example shown in FIG. As a result, as shown by a one-dot chain line in FIG. 2, an electronic component such as a diode for absorbing a surge voltage or a capacitor for noise suppression, or an electronic circuit board for controlling the operation time of the ICR relay is arranged. Space can be secured.

Further, in the electromagnetic switch 6 according to the first embodiment, the end cover 42 is fixed to the center case 38 with the four screws 44, and therefore, the conventional switch that fixes the end cover 130 shown in FIG. In comparison, the pitch of the screw fixing portions can be shortened. Accordingly, the pressure distribution of the gasket 43 that seals between the center case 38 and the end cover 42 can be made more uniform than in the conventional case in which the screws 43 are fixed with three screws, so that the sealing performance can be improved.
Further, by setting only the fourth screw fixing portion at a position far from the axial center O of the solenoid SL, a corner portion protruding outward is formed on the outer shape of the center case 38 in which the fourth screw fixing portion is set. Thereby, when the starter 1 is assembled to the engine, the worker can easily hold and hold the corner portion protruding to the outside of the center case 38, so that workability is improved.

[Modification]
The reduction type starter 1 described in the first embodiment is a method in which the operation for pushing out the pinion shaft 3 and the operation for opening and closing the main contact are performed by one electromagnetic switch 6, but the operation for pushing out the pinion shaft 3 and the main contact are performed. A system in which the opening and closing operation is performed by separate solenoids may be used. Specifically, a center case 38 that includes a first solenoid that pushes out the pinion shaft 3 and a second solenoid that opens and closes the main contact, forms an outer frame of the second solenoid, and a rear-side opening of the center case 38. The configuration of the present invention can be applied to the end cover 42 that closes the end.

1 Reduction type starter 2 Motor 6 Electromagnetic switch 25 Coil 26 Plunger 34 Return spring 37 Moving contact 38 Center case 40 Insulator 42 End cover 43 Gasket 44 Screw SL Solenoid O Solenoid shaft center

Claims (2)

A set of fixed contacts connected to the energization circuit of the motor (2);
A movable contact (37) for electrically opening and closing between the set of fixed contacts;
A solenoid (SL) for driving the movable contact (37) in the axial direction opposite the set of fixed contacts;
The solenoid (SL) is
A coil (25) that forms an electromagnet upon energization;
A plunger (26) that is attracted to the electromagnet and moves to one side in the axial direction;
A return spring (34) for pushing back the plunger (26) when energization to the coil (25) is stopped and the attractive force of the electromagnet disappears;
A resin insulator (40) for holding the movable contact (37) with respect to the plunger (26);
A cylindrical center case (38) forming an outer frame of the solenoid (SL);
A metal end cover (42) that closes the opening end of the center case (38) that opens to the other side in the axial direction, and the end cover (42) is a plurality of screws (44). Tightened and fixed to the case (38)
When the attracting force of the electromagnet disappears and the plunger (26) is pushed back by the return spring (34), the insulator (40) comes into contact with the end cover (42), so that the plunger (26) An electromagnetic switch for starter (6) whose return position is regulated,
The center case (38) is provided in a polygonal shape in which the cross-sectional shape orthogonal to the axial direction has six corners ,
The end cover (42) has six corners corresponding to the cross-sectional shape of the center case (38), and the screws (44) are respectively formed at four corners of the six corners. Is fixed to the center case (38) by
When a place where the end cover (42) is fixed to the center case (38) with the screw (44) is referred to as a screw fixing portion, three screw fixing portions among the four screw fixing portions are: Provided at a position equidistant from the axial center (O) of the solenoid (SL), the remaining one screw fixing portion extends from the axial center (O) of the solenoid (SL) to the three screw fixing portions. An electromagnetic switch for a starter, characterized in that it is set at a position farther than the distance . The starter electromagnetic switch (6) according to claim 1,
A starter electromagnetic switch , wherein a gasket (43) is inserted between the center case (38) and the end cover (42) .

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