JP2010071078A - Engine starting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep connection of a fixed contact and a bolt in a stable state while reducing transfer of heat of the bolt to the fixed contact side. <P>SOLUTION: A switch part S has a structure in which a movable contact 22 displacing with excitation of an electromagnetic control part E, and a first fixed contact 26 which is fixed on a switch chamber R formed on a brush holder stay 6 of a motor part M and which the movable contact 22 contacts and separates from are provided, a shaft part 28 of a conductive terminal bolt 28 is made to penetrate through a section on which the first fixed contact 26 of the switch chamber R is fixed toward an outside and contact a battery power source, an annular projection rib 28d positioned at a shaft part 28b outer diameter side is formed at a head part 28a of the terminal bolt 28, and the projection rib 28d is made to abut on the first fixed contact 26 to establish connection. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention belongs to the technical field of an engine starting device for starting an internal combustion engine such as a vehicle.

Generally, in this type of engine starter, a motor unit having a motor shaft that transmits power to an output gear that starts the engine, a switch unit that switches power supply to the motor unit intermittently, and an electromagnetic control that controls switching of the switch unit There are some which are configured with a part. In this configuration, the switch unit includes a movable contact that is displaced by excitation of the electromagnetic control unit in a switch chamber formed in the brush holder stay of the motor unit, and a fixed contact that is fixed to the switch chamber and that the movable contact contacts and disconnects. And connecting the shaft portion of the conductive bolt to the battery power source through the fixed contact fixing portion of the switch chamber facing the outside, and connecting the head portion of the bolt to the fixed contact, the movable contact When the movable contact and the fixed contact come into contact with each other, the battery power is supplied to the brush of the motor unit.
By the way, since such an engine starting device is disposed in the engine room, the engine side becomes hot and humid as the engine is continuously driven, but the battery side is similarly hot. On the other hand, as the engine stops, the temperature of the battery as well as the engine starter decreases, but in the process of the temperature decrease, the temperature of the battery exposed to the outside air drops before the inside of the engine starter, While the bolt connected to the battery side decreases in temperature via the battery cable, the temperature in the engine starting device becomes high. In this state, the temperature-decreasing bolt and the fixed contact whose temperature has decreased due to contact with the bolt are placed in a high-temperature atmosphere in the engine starting device, and there is a problem that condensation occurs on these. . Furthermore, if the inside of the engine starter is further cooled while condensation has occurred, the condensation may freeze. In such a case, it is assumed that the switch function between the fixed contact and the movable contact will not operate. There is.

In order to improve this, a plurality of protrusions are formed on the head of the bolt connected to the fixed contact, the protrusion and the fixed contact are in contact with each other, and the bolt head and the fixed contact are electrically connected. On the other hand, it has been advocated that the contact area between the bolts and the fixed contacts is prevented so that the heat conduction between the bolts and the fixed contacts is prevented.
JP 2002-130092 A

  However, in the conventional device, the head portion of the bolt that comes into contact with the fixed contact is formed in a square shape, and a protrusion is formed at the corner portion of the rectangular shape head. In the point contact state, it is configured to abut on a portion away from the shaft portion. For this reason, when a strong tightening force acts when screwing and tightening the nut to the shaft portion of the bolt that penetrates the brush holder stay, an axial force that is pulled toward the nut side acts on the shaft portion, The axial force also acts on the central portion which is the shaft forming portion of the head. At this time, the head and the fixed contact are in a state in which the protrusions located at four positions in the circumferential direction of the head and the fixed contact are in contact with each other. It is assumed that the corner part will be warped away from the fixed contact, and if this happens, there is a problem that there is a possibility that the projection of the bolt head and the fixed terminal cannot maintain a stable connection state, Here is the problem to be solved by the present invention.

SUMMARY OF THE INVENTION The present invention was created in view of the above-described circumstances to solve these problems, and the invention of claim 1 is a motor having a motor shaft that transmits power to an output gear for starting an engine. An engine starter comprising: a switch unit that intermittently switches power supply to the motor unit; and an electromagnetic control unit that controls switching of the switch unit. The switch unit is displaced in accordance with excitation of the electromagnetic control unit. It has a movable contact and a fixed contact that is fixed to the switch chamber formed on the brush holder stay of the motor unit, and the movable contact is separated from the contact. The shaft portion of the conductive bolt is directed from the fixed contact fixing portion of the switch chamber to the outside. The bolt head is connected to the battery power source, while the bolt head is connected to the fixed contact. An engine starting apparatus annular collision ribs are formed in contact with.
The invention according to claim 2 is the engine starting device according to claim 1, wherein the projecting rib is formed concentrically in the vicinity of the shaft portion.
The invention according to claim 3 is the engine starter according to claim 1 or 2, wherein the projecting rib is formed to have a projecting distal end surface narrower than the projecting proximal end side.

According to the first aspect of the present invention, there can be provided a highly reliable engine starter without a problem that the head of the bolt is warped and the connection state between the bolt and the fixed contact becomes unstable.
According to the invention of claim 2, not only the head of the bolt is reinforced, but also the connection state with the fixed contact can be made more stable.
According to the invention of claim 3, while the head of the bolt can be reinforced, the contact area with the fixed contact can be reduced, and the reliability can be further improved.

Next, embodiments of the present invention will be described with reference to the drawings.
In the drawings, reference numeral 1 denotes an engine starter (starter) for starting an engine mounted on a vehicle or the like, and a motor part (electric motor) M constituting the engine starter 1 is a general-purpose brush type DC motor. The base end of the motor shaft 2 is rotatably supported by an end cover 3 a that closes the base end side opening of the cylindrical yoke 3, while the motor shaft 2 has a commutator at the tip end thereof. A (commutator) 4 is integrally fitted. In addition, a ring-shaped brush holder stay 5 which is a constituent member of the motor unit M and a constituent member of the switch unit S which will be described later is incorporated in the outer periphery of the commutator 4. The stay 5 is set so as to be incorporated in the opening on the front end side of the yoke 3.

  Reference numeral 6 denotes a bottomed cylindrical case body that constitutes a speed reducing portion D arranged in a state adjacent to the front end side of the motor portion M, that is, the brush holder stay 5, and the case body 6 includes the motor A tip 2a of the shaft 2 is internally provided. Further, the base end portion of the drive shaft 7 is arranged on the case body 6 so as to be fitted around the motor shaft distal end 2a so as to be relatively rotatable. The case body 6 includes a plurality of planetary gears 8 that mesh with the inner peripheral surface of the case body 6 and the motor shaft tip 2a and rotate in the circumferential direction in the case body 6 as the motor shaft 2 rotates. A ring-shaped support plate 9 that is arranged concentrically with the motor shaft tip 2a and to which the support shafts 9a of the plurality of planetary gears 8 are coupled is provided. The rotation of the planetary gear 8 in the circumferential direction is set to be interlocked with the drive shaft 7 by the inner peripheral surface of the support plate 9 being fitted around the drive shaft 7 in a non-rotating manner. As a result, the driving force of the motor unit M is set to be transmitted to the drive shaft 7 in a decelerated state.

  The distal end portion of the drive shaft 7 is provided with a one-way rotation type clutch portion C. The clutch outer 10 formed of a stepped cylindrical body constituting the clutch portion C is disposed on the proximal end side. The helical spline 10b formed on the inner peripheral surface of the small-diameter cylindrical portion 10a positioned is fitted on the drive shaft 7 in a state where the helical spline 10b is engaged with the helical spline 7a formed on the outer peripheral surface of the tip end portion of the drive shaft 7. When a relative rotation in a predetermined rotational direction occurs between the drive shaft 7 and the clutch outer 10, the clutch outer 10 rotates and moves along the drive shaft helical spline 7a and moves toward the base end side of the drive shaft 7. Set to move (displace) between the non-starting position (position shown in the upper half in FIG. 1) and the starting position on the tip side (position shown in the lower half in FIG. 1). Has been. Further, a clutch inner 12 having a pinion gear 11 formed on the outer peripheral portion of the tip is connected to the inside of the large-diameter cylindrical portion 10c on the tip side of the clutch outer 10. The clutch inner 12 is integrally moved (displaced) in the axial direction of the motor shaft 2 (drive shaft 7) with respect to the clutch outer 10, and is moved (rotated) in the circumferential direction by a predetermined (one) rotation. The direction of rotation is integrally linked, but the other rotation direction is freely linked. Further, the clutch inner 12 is incorporated in the drive shaft 7 so as to be loosely fitted, and is provided so as to be rotatable relative to the drive shaft 7. The clutch inner 12 is pushed to the tip side by the displacement of the clutch outer 10 from the non-starting position to the starting position accompanying the rotation of the drive shaft 7 in the predetermined rotation direction, and the pinion gear 11 on the tip side is pushed. It is set so as to mesh with the ring gear 13 on the engine side, and is set so as to start the engine as the drive shaft 7 rotates in a predetermined rotation direction in this state.

Further, an electromagnetic control unit E is provided between the speed reduction unit D and the clutch unit C. The electromagnetic control unit E is housed in the cylindrical gear cover 14 together with the speed reduction unit D and the clutch unit C.
Here, a clutch stopper 15 is disposed between the clutch portion C and the electromagnetic control portion E, and the clutch stopper 15 is assembled into a stepped portion 14a formed in the gear cover 14 so as to be abutted. While the movement toward the distal end side is restricted, the movement toward the proximal end side is restricted by the exciting coil unit 16 that constitutes the electromagnetic control unit E that is press-fitted into the proximal end side of the clutch stopper 15. Thus, the movement of the clutch portion C toward the proximal end side is restricted and the exciting coil unit 16 is protected.
Further, the clutch outer 10 is moved to the proximal end side (non-starting position side) in the axial direction of the drive shaft 7 by the first elastic machine 10d mounted between the stopper member 7b provided on the distal end side of the drive shaft 7. In the non-starting position of the clutch portion C, the clutch outer large-diameter cylindrical portion 10c is in a state of elastically contacting the clutch stopper 15 while receiving the urging force of the first ammunition 10d. It is configured as follows.

  The exciting coil unit 16 is made of a magnetic material, accommodates a coil body 16d in which a coil bobbin 16b is wound with a winding 16c in a bottomed cylindrical coil holder 16a having an opening at the tip side, and a ring-shaped plate at an opening end. It is configured by caulking a second exciter 18 having a shape of an exciting piece 17 and a ring-like plate shape and having an urging piece 18a on the inner diameter side. As described above, the excitation coil unit 16 is press-fitted in a state of abutting from the base end side against the clutch stopper 15 that is preliminarily incorporated in the cylindrical portion of the gear cover 14. Is set so that movement in the axial direction and the circumferential direction with respect to the gear cover 14 is restricted.

The first and second plunger units 19, which are constituent members of the electromagnetic control unit E, are provided in a ring-shaped predetermined gap formed between the inner peripheral surface of the excitation coil unit 16 and the outer peripheral surface of the drive shaft 7. 20 are laminated | stacked on radial direction, and are arrange | positioned so that an axial direction movement is possible. The first and second plunger units 19 and 20 are displaced in the axial direction based on the switching between excitation and non-excitation of the excitation coil unit 16, respectively. It is set to be displaced.
The first plunger unit 19 is made of a magnetic material, and has a cylindrical first plunger main body 19a along the inner peripheral surface of the exciting coil unit 16, and extends from the base side edge of the first plunger main body 19a to the outer diameter side. And a flange portion 19b that is locked to the coil holder 16a is integrally formed. The outer periphery of the flange portion 19b (in the upper portion of the outer periphery of the flange portion 19b in FIG. 1), the shaft mounting portion 19c is on the outer diameter side. It protrudes and the tip part of the switch shaft 21 used as the structural member of the switch part S is being fixed here. The first plunger unit 19 is in contact with the urging piece 18a of the second elastic machine 18 crimped to the exciting coil unit 16 on the front end surface of the first plunger main body 19c. The machine 18 is configured to urge the first plunger unit 19 toward the proximal end side (non-operating position side).
Reference numeral 19d denotes a ring-shaped bullet receiving plate disposed on the inner peripheral surface proximal end portion of the first plunger main body 19a.

The second plunger unit 20 is disposed with the drive shaft 7 fitted on the inner diameter side of the first plunger unit 19, that is, in the cylinder of the first plunger main body 19a. Reference numeral 20 is arranged in a state in which relative movement in the axial direction is free with respect to the first plunger main body 19a and the drive shaft 7. The second plunger unit 20 is a non-magnetic material, and in this embodiment, a slide body 20a made of a resin material and a ring-shaped second plunger made of a magnetic material and having an inner diameter side portion embedded in the slide body 20a. It is comprised with the main body 20b. And the 2nd plunger 20 is urged | biased toward the front end side (action position side) by the 3rd bullet machine 20c interposed between the bullet receiving plate 19d distribute | arranged to the 1st plunger main body 19a. The clutch outer 10 is configured to come into contact with the clutch outer 10 in a state of receiving the urging force of the third bullet 20c.
The first and second plunger units 19 and 20 are such that the distal end surface of the first plunger main body 19a is positioned closer to the excitation piece 17 than the distal end surface of the second plunger main body 20b in the non-operating position of both. It is arranged. Thus, when the exciting coil unit 16 is in an excited state, the first plunger unit 19 is set to be attracted to the exciting piece 17 and displaced to the operating position prior to the second plunger unit 20.

  In the electromagnetic control unit E configured as described above, when the exciting coil unit 16 is in a non-excited state, the first plunger unit 19 receives the urging force from the urging piece 18a of the second elastic machine 18 to receive the flange portion 19b. Is in contact with the bottom of the case body 6 of the speed reduction part D and is set to be in a non-acting position away from the coil holder 16a of the exciting coil unit 16. Further, the second plunger unit 20 is set so that the urging force of the third ammunition 20c is smaller than the urging force of the first ammunition 10d disposed on the clutch outer 10, and is pushed back to the clutch outer 10. The distal end surface of the second plunger main body 20b is set so as to be located at a non-acting position located on the proximal end side from the distal end surface of the first plunger main body 19a (see the upper half of FIG. 1). In this state, the large-diameter cylindrical portion 10c of the clutch outer 10 is configured to abut against the clutch stopper 15 in a resilient manner.

When the ignition switch (not shown) provided on the vehicle is turned on from the non-excited state to turn it on and the exciting coil unit 16 is excited to magnetize the excited piece 17 (excited state), the excited piece 17 The first and second plunger main bodies 19 a and 20 b are set so as to be attracted and located at the working position. The first plunger main body 20 a is excited at the tip surface more than the tip surface of the second plunger main body 20. Since it is located on the side of the piece 17, the first plunger main body 19 a is sucked in advance against the urging force of the second ammunition 18, and the collar portion 19 b moves in contact with the bottom piece 16 e of the coil holder 16 a. It is set so as to be displaced to the operation position to be regulated. At this time, the switch shaft 21 provided in the first plunger 19 is displaced in the direction of the motor shaft 2 together with the first plunger 19 (see the two-dot chain line in the upper half of FIG. 1). Along with the displacement of the plunger 19 to the operating position, a movable contact 22, which is a constituent member of the switch unit S, is provided at the base end of the switch shaft 21, and the battery and the motor unit M are electrically connected to supply power to the motor unit M. It is configured to supply and rotate the drive shaft 7 via the motor shaft 2.
Further, in the process of displacement of the first plunger unit 19 from the non-operating position to the operating position, the distal end surface of the first plunger main body 19a becomes the exciting piece 17 in a state of elastically deforming the second bullet urging piece 18a. It is set so that the third bullet machine 20c interposed between the second plunger unit 20 and the second plunger unit 20 is stored by approaching.

When the motor unit M is driven and the drive shaft 7 is rotated as the first plunger unit 19 is displaced to the operating position, the engine starter 1 moves between the clutch outer 10 of the clutch device C and the drive shaft 7. The relative rotation occurs based on the helical splines 7a and 10b, and the clutch outer 10 and the clutch inner 12 are set to be pushed out toward the starting position on the front end side. On the other hand, when the third bullet 20c is accumulated in the process of displacement of the first plunger unit 19 to the operating position, and the biasing force of the third bullet 20c becomes larger than the bias of the first bullet 10d, The two plunger main body 20b is configured to be attracted to the excitation piece 17 and displaced to the operating position against the urging force of the first ammunition 10d. As a result, the clutch outer 10 and the clutch inner 12 of the clutch part C are pushed to the tip side with relative rotation with the drive shaft 7 and receive the pushing force due to the displacement of the second plunger body 20b to the operating position. The clutch portion C is displaced to the starting position so that the operation of meshing the pinion gear 11 and the ring gear 13 of the clutch inner 12 is smoothly performed. (See the lower half of FIG. 1).
When the engine is started and the excitation coil unit 16 is de-energized, the excitation piece 17 is demagnetized, and the first plunger unit 19 is displaced to the non-operating position while receiving the urging force of the second ammunition 18. On the other hand, the second plunger unit 20 is inoperative in a state where it receives the urging force of the first ammunition 10d set to be larger than the third ammunition 20c that urges the second plunger unit 20 toward the distal end. At this time, the clutch outer 10 and the clutch inner 12 are set to be displaced to the non-starting position in response to the urging force of the first ammunition 10d.

  On the other hand, the brush holder stay 5 which is a constituent member of the motor part M and the switch part S is integrally formed of an insulating resin material, and the brush holder stay 5 makes the commutator 4 of the motor shaft 2 loosely fit. A penetrating through hole is formed, and is provided with a disc-like stay main body 5a fitted into the open end of the yoke 3, and four holders in the circumferential direction are provided on the base end side surface of the stay main body 5a. The part 5b is long in the radial direction and is formed in a protruding shape toward the axial direction proximal end side. Each of these holder portions 5b is located in the upper half of the stay main body 5a in each of the right side views of FIGS. 2 and 3B, and the pair of holder portions 5b adjacent in the circumferential direction has an anode brush 23. Are housed (supported) so as to be able to appear and retract, and a cathode brush 24 is provided so as to be capable of appearing and retracting in a pair of holder parts 5b located in the lower half of the stay main body 5a and adjacent in the circumferential direction. . Further, each holder portion 5b accommodates urging ammunition machines 23a and 24a located on the outer diameter side of the anode and cathode brushes 23 and 24, and the inner diameter side end surfaces of the brushes 23 and 24 are respectively provided. The commutator 4 is configured to be slidably contacted with the outer peripheral surface of the commutator 4.

Further, a ring-shaped conductive plate 25 is integrally provided on the tip side surface of the stay main body 5a so as to be positioned between the opening end portion of the case body 6 constituting the speed reducer D. The lower end portion is an exposed portion 25a exposed to the base end side through a notch portion 5c formed in the lower end portion of the stay main body 5a, and is provided in the lower half of the stay main body 5a. Pigtails 24b drawn from the cathode brush 24 housed in the holder 5b are connected to each other. The conductive plate 25 is connected to a cathode side power source of a battery provided on the vehicle body side (not shown), and is configured to supply the cathode side power source to the cathode brush 24.
A cylindrical portion 25b protruding toward the base end side is formed at the peripheral edge portion of the through hole formed on the inner diameter side of the conductive plate 25, and the cylindrical portion 25b is connected to the distal end side of the commutator 4. It is configured to prevent the lubricant applied to the reduction gear D side from entering the motor part M side by being fitted between the recess formed in the inner diameter part and the outer peripheral surface of the motor shaft 2. .

On the other hand, an upright piece portion 5d is integrally formed above the stay main body 5a of the brush holder stay 5 so as to protrude in the outer diameter direction beyond the yoke 3, and the switch portion S extends from the upright piece portion 5d. The lower part of the upright piece 5d is provided at a part extending between the pair of holder parts 5b on which the anode brush 23 in the upper half of the stay main body part 5a is supported.
That is, the left and right peripheral piece portions 5e projecting toward the base end side from the left and right end edges of the standing piece portion 5d are formed, and the upper peripheral piece projecting toward the base end side from the upper end edge of the standup piece portion 5d. The portion 5f is integrally formed, and thereby, a switch chamber R surrounded by the standing piece 5d, the left and right circumferential pieces 5e, and the upper circumferential piece 5f is formed in an upper portion of the stay body 5a. . A through hole 5g penetrating in the axial direction is formed in the protruding base end portion of the standing piece 5d in the switch chamber R, and the upper portion of the through hole 5g in the switch chamber R corresponds to the fixed contact of the present invention. A first fixed contact 26 is disposed, and a second fixed contact (terminal plate) 27 is disposed below the through-hole 5f, and between the first and second fixed contacts 26, 27. Is provided with a predetermined gap in the vertical direction with the through hole 5g positioned between them, and the first and second fixed contacts 26, 27 are insulated from each other and are not conducted. Yes.

The first fixed contact 26 is formed in an L shape using a conductive metal material (made of copper in the present embodiment), and the one piece 26a faces the proximal end side of the standing piece 4d of the switch chamber R. The other piece 26b is fixed to the lower surface (inner surface) of the upper peripheral piece 5f of the switch chamber R. The other piece 26b and the upper peripheral piece portion 5f are provided with through-holes, and terminal bolts 28 corresponding to the bolts of the present invention pass through these through-holes. It is configured to conduct (connect).
That is, the terminal bolt 28 is made of a conductive member, and includes a head portion 28a formed in a square shape and a shaft portion 28b in which a screw groove is engraved. 28b is inserted into the through hole from the inside of the switch chamber R, the tip of the shaft portion 28b is protruded upward from the upper peripheral piece 5f, and the nut 28c is screwed into the protruding tip portion of the shaft portion 28b. The bolt 28 is configured to be fixed to the switch chamber R. In this fixed state, the head portion 28a of the terminal bolt 28 abuts against the first fixed contact 26 to be electrically connected, and the shaft portion 28b protruding above the terminal bolt 28 has an anode of a not-shown battery. Is connected to the first fixed contact 26 via the terminal bolt 28.

In this case, as shown in FIGS. 4 and 5, the head portion 28 a of the terminal bolt 28 is a surface on the side from which the shaft portion 28 b protrudes and faces the first fixed contact 26. A ring-shaped protruding rib 28d is formed on the outer diameter side and protruding in the extending direction of the shaft portion 28b. When the terminal bolt 28 is tightened with the nut 28c, the flat ring-shaped protruding end surface 28e of the protruding rib 28d and the lower surface of the other piece 26b of the first fixed contact 26 come into contact with each other. An electrical connection with the contact 26 is made.
Here, the protruding rib 28d is located in the vicinity of the shaft portion 28b and is concentric with the shaft portion 28b. Thus, by forming the protruding rib 28d on the head 28a, the head 28a can be reinforced and the rigidity can be increased. Moreover, when the nut 28c is tightened, a large tightening force is applied to the shaft 28a. Even if an axial force that is pulled toward the nut 28c acts on the portion 28b, the head 28a is not warped by receiving the axial force on the annular protruding rib 28d, and the protruding rib 28d and the It is configured so that the contact state with the one fixed contact other piece 26b does not become unstable.
Further, the projecting rib 28d is formed in a tapered shape with a narrower radial width toward the projecting distal end side, and is configured such that the area of the projecting end surface 28e is smaller than the projecting proximal end side portion. As a result, the protruding rib 28d can be widened on the protruding proximal end side to reinforce the head portion 28a, and the protruding distal end side can be made narrower protruding end surface 28e to reduce the contact area with the other piece 26b. When the temperature of the terminal bolt 28 is lower than the internal temperature of the engine starting device 1, the temperature of the first fixed contact 26 that contacts the terminal bolt 28 is lowered in the same manner as the terminal bolt 28. It is configured so that there is no such thing.

On the other hand, the free ends of the pigtails 23 b drawn from the pair of anode brushes 23 in the upper half of the stay main body 5 a of the brush holder stay 5 are connected (conducted) to the second fixed contact 27.
Further, the through hole 5g of the stay main body 5a is integrally formed with a cylindrical portion 5h that protrudes from the hole edge toward the distal end side in the axial direction, and the cylindrical portion 5h is laminated on the brush holder stay 5 in the axial direction. The conductive plate 24 and the case body 6 constituting the speed reduction part D are formed so as to protrude to the electromagnetic control part E side. A switch shaft 21 that is integrally connected to the first plunger unit 19 that constitutes the electromagnetic control unit E and is displaced between the operating position and the non-operating position is penetrated and supported by the cylindrical portion 5h. As the plunger unit 19 is displaced, the plunger unit 19 is displaced in the axial direction. Furthermore, the base end side end portion of the switch shaft 21 is configured to project toward the switch chamber R side, and the base end side end portion of the shaft 21 projecting toward the switch quality R side, as described above. A movable contact 22 is provided. The movable contact 22 is formed of a conductive member in a quadrangular shape, and has an upper half portion facing the first fixed contact 26 and a lower half portion facing the second fixed contact 27.
Reference numeral 29 denotes a switch chamber cover made of a rubber elastic material that covers a base end side portion of the switch chamber R that is open.

As described above, the first plunger unit 19 is displaced between the operating position and the non-operating position on the basis of switching between excitation and non-excitation of the excitation coil unit 16 of the electromagnetic control unit E. In this case, In the non-acting position of the first plunger unit 19, the switch shaft 21 is located in the non-conducting position. In this state, the movable contact 22 and the first and second fixed contacts 26, 27 are separated in the axial direction. Thus, the first and second fixed contacts 26 and 27 are configured to be insulated. When the first plunger unit 19 is displaced to the operating position, the switch shaft 21 is located at the conduction position displaced to the distal end side. When this state is reached, the upper and lower halves of the movable contact 22 are first and second respectively. The movable contact 22 is configured to electrically contact (connect) the first and second fixed contacts 26, 27 in contact with the fixed contact members 26, 27. At this time, the movable contact 22 receives the urging force of the fourth ammunition 22 a having an urging force smaller than the urging force of the second ammunition 18 so as to come into contact with the first and second fixed contacts 26 and 27. Thus, consideration is given to ensure that the switch is switched by the switch unit S.
As described above, when the movable contact 22 of the switch unit S and the first and second fixed contacts 26 and 27 are connected, the anode brush 23 on the upper half side of the stay body 5a is connected to the anode brush 23 as described above. Since the anode-side power is supplied and the cathode-side power of the battery is supplied to the cathode brush 24 on the lower half side in advance, the power supply to the motor unit M is started, whereby the rotation of the motor shaft 2 is started. Accordingly, the drive shaft 7 is rotated, and relative rotation is performed between the drive shaft 7 and the clutch outer 10 to push the clutch device C to the tip side.

  In the present embodiment configured as described, the engine starter 1 first turns on the exciting coil unit 16 of the electromagnetic control unit E when the ignition switch (not shown) is turned ON. When one plunger unit 19 is displaced to the operating position, the movable contact 22 provided on the switch shaft 21 conducts the first and second fixed contacts 26 and 27 of the switch unit, and supplies battery power to the motor unit M. The drive shaft 7 is rotated to push the clutch portion C toward the starting position, and the second plunger unit 20 is moved to the working position in accordance with the clutch portion C being pushed based on the relative rotation with the drive shaft 7. So that the clutch portion C is smoothly displaced to the starting position, and the pinion gear 11 and the ring gear 13 are engaged to start the engine. It has been made. In this case, the terminal bolt 28 for conducting the first fixed contact 26 to the anode of the battery is such that the surface of the head portion 28a on the extending side of the shaft portion 28b contacts the lower surface of the first fixed contact other piece 26b. Although connected (conducted), an annular projecting rib 28d is formed on the head 28a, and the projecting end surface 28e of the projecting rib 28d and the first fixed contact other piece 26b are connected to each other. Therefore, the contact area between the terminal bolt 28 and the first fixed contact 26 is small, heat conduction from the first fixed contact 26 to the terminal bolt 28 can be reduced, and the terminal bolt 28 whose temperature has decreased is connected via the contact portion. It can be prevented that the heat of the one fixed contact 26 is conducted to the terminal bolt 28 side and the temperature of the first fixed contact 26 is lowered. Moreover, when the terminal bolt 28 is fastened to the switch chamber R by the nut 28c, it is assumed that an axial force based on the fastening force of the nut 28c is applied to the shaft portion 28b. The axial force is caused by the protruding rib 28d and the outer diameter of the shaft portion 28b. Since it is received in an annular shape on the side, there is no problem that the head 28a is warped and the connection state between the terminal bolt 28 and the first fixed contact 26 becomes unstable, and the engine starts with high reliability. A device 1 can be provided.

  As described above, in the embodiment in which the present invention is implemented, the connection between the terminal bolt 28 and the first fixed contact 2 can be maintained in a stable state, but the protruding rib 28d further includes the shaft portion 28b. Since it is formed in the vicinity and concentrically with the shaft portion 28b, not only can the head portion 28a be reinforced to increase the rigidity, but also the contact between the protruding rib 28d and the first fixed contact other piece 26b can be improved. The contact state (connection state) can be maintained in a more stable state.

  Further, in this structure, the projecting rib 28d is formed in a tapered shape with a radial width narrower toward the projecting tip side, so that the projecting proximal end side of the projecting rib 28d is widened so that the bolt head 28a can be removed. The projecting rib 28d has a narrow projecting end surface 28e on the projecting tip side, and the contact area with the other piece 26b can be further reduced, and the heat between the terminal bolt 28 and the first fixed contact 26 can be reduced. The conduction can be further reduced, and therefore, the occurrence of condensation at the first fixed contact 26 is reduced, and the reliability can be further improved.

It is a partial cross section front view of an engine starting device. It is a right view of the state which assembled the other member in the brush holder stay. 3A and 3B are a plan view and a right side view of the brush holder stay, respectively. 4A, 4B, and 4C are a plan view, a front view, and a bottom view of the terminal bolt, respectively. It is a perspective view of a terminal bolt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine starter 2 Motor shaft 5 Brush holder stay 5a Stay main body 5b Holder part 5d Standing piece part 7 Drive shaft 16 Excitation coil unit 19 First plunger unit 20 Second plunger unit 21 Switch shaft 22 Movable contact 23 Anode brush 26 First One fixed contact 27 Second fixed contact 28 Terminal bolt 28a Head 28d Projected rib 28e Projected end surface

Claims (3)

  In an engine starter comprising a motor unit having a motor shaft that transmits power to an output gear for starting an engine, a switch unit for switching power supply to the motor unit intermittently, and an electromagnetic control unit for switching control of the switch unit The switch unit includes a movable contact that is displaced in accordance with excitation of the electromagnetic control unit, and a fixed contact that is fixed to a switch chamber formed on the brush holder stay of the motor unit, and the movable contact is separated from and connected to the conductive bolt. The shaft part of the bolt is penetrated from the fixed contact fixing part of the switch chamber to the outside and connected to the battery power supply, while the bolt head part is connected to the fixed contact, An engine starting device in which an annular projecting rib that is located on the outer diameter side and abuts against a fixed contact is formed.   The engine starting device according to claim 1, wherein the protruding rib is formed concentrically in the vicinity of the shaft portion.   The engine starting device according to claim 1 or 2, wherein the projecting rib is formed to have a projecting distal end surface narrower than the projecting proximal end side.

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