JPH02125966A - Coaxial form starter device - Google Patents

Abstract

PURPOSE:To prevent the bad slide of a plunger due to the wear dust of brushes or the like, by forming a pipe like body on the outer side surface of an end wall making it protrude to the inside of the plunder of an electromagnetic switch device, and at the same time, making a constitution so that the contact between a movable contact point and a fixed contact point may be made to be conducted within the system of the pipe like body. CONSTITUTION:An output rotary shaft 28 is arranged on the same axis with the armature rotary shaft 26 of a DC motor 25, and a pinion 29 meshable with the ring gear of an engine, is provided on the side of its one end so as to be able to project forward. Also, a bowl shaped rear bracket 32 is put on the york rear end portion of the DC motor 25, and an electromagnetic switch device 42 is fitted at its rear part. And a pipe like flange portion 32c protruding into the inner part of the motor at the center portion of an end wall, is integrally formed at the rear bracket 32, and at the same time, a brush support and terminal aggregate 38 in which a retaining portion 35 retaining a plurality of brushes 34 slide-contacting a commutator 24, an end portion terminal bolt 36, a power source side fixed contact point 37a and a brush side fixed contact point or the like, are integrally unitarized by means of resin, is arranged on the inner side of the rear bracket 32.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coaxial starter device, and more particularly to a coaxial starter device used for starting a vehicle engine.

(Prior art) Conventionally, this type of coaxial starter device was developed in U.S. Patent No. 63714
This is well known as disclosed in Publication No. 74 (Utility Model Application No. 166198/1988). As shown in FIG. 3, the conventional coaxial starter device disclosed in this publication includes a DC motor 1 having a tubular armature rotating shaft 1a, and a planetary motor installed on the axial end side of the DC motor l. The armature rotation shaft 1 is connected to the armature rotating shaft 1 via a driving force transmission device 3 including a gear reduction mechanism
An output rotating shaft 4 supported slidably in the axial direction to which the rotation of a is transmitted, a pinion 5 provided at the front end of the output rotating shaft 4, and a pinion 5 provided directly at the other end in the axial direction of the electric motor. The armature rotation shaft 1a of the DC motor 1 and the electromagnetic switch device 6 are arranged on the same axis.

In such a conventional coaxial starter device, the rear bracket 7 of the DC motor 1 has an opening formed in its end face, and the power supply side fixed contact 8a and the brush side fixed contact are inserted into the electromagnetic switch device 6 through the opening. Contact point 8b protrudes. On the other hand, the electromagnetic switch device 6 includes a cylindrical plunger 1 disposed so as to be slidable in the axial direction inside the excitation coil 9.
0, and one end of a rod 11 arranged on the central axis of the plunger 10 is fixed to the plunger 10. The other end of this rod 11 is inserted through the central opening of the rear bracket 7 and enters the armature rotating shaft la of the DC motor 1, and functions to push out the output rotating shaft 4. A movable contact 12 is supported on a rod 11 inside the electromagnetic switch device 6, and as the rod 11 is moved in the axial direction by the plunger 10, the movable contact 12 connects to two fixed contacts 8a and 8b protruding from the end opening of the rear bracket 7. make contact and short-circuit both fixed contacts.

(Problems to be Solved by the Invention) However, in the conventional coaxial starter device, brush wear powder in the DC motor 1 may pass through the end face opening of the rear bracket 7 and enter the electromagnetic switch W6, or the electromagnetic switch Movable contact 12 and fixed contact 8a of group Wt6
, 8b falls down and the excitation coil 9
There was a risk that the plunger would be deposited on the inner surface, that is, the sliding surface, of the sleeve 13 for sliding during the plunge fitted to the inner peripheral part of the bobbin, resulting in poor sliding of the plunger. If sliding failure occurs in the plunger 10, the fixed contact 8a of the movable contact 12 will naturally
, 8b occurs, and as a result, the DC motor l
will no longer operate, which will have a serious impact on the function of the starter device itself.

An object of the present invention is to provide an electromagnetic switch device at the rear of the motor, and to provide a contact point for turning on the motor power inside the electromagnetic switch device, and to prevent brush abrasion powder or contact abrasion during the plunge of the electromagnetic switch device when communicating with the inside of the motor. An object of the present invention is to provide a coaxial starter device that does not cause sliding defects due to powder or the like.

(Means for Solving the Problems) The present invention includes an armature rotating shaft of an electric motor, an output rotating shaft having a pinion at the front end and supported so as to be slidable in the axial direction, and an electromagnetic shaft attached to the rear end of the electric motor. In a coaxial starter device in which a switch device is arranged on the same axis, a window for protruding a fixed contact formed in an end wall of a rear bracket attached to a rear end of a cork of the electric motor, and a rear end of the electric motor. A power supply side fixed contact and a brush side fixed contact arranged in the rear bracket and protruding into the inside of the electromagnetic switch device from the window of the end wall of the rear bracket, an excitation coil constituting the electromagnetic switch device, and an excitation coil that slides in the axial direction inside the electromagnetic switch device. a plunger having a substantially U-shaped cross section, a rod attached to the plunger and supporting a movable contact that extends along the central axis of the plunger and abuts to short-circuit both of the fixed contacts; and an end surface of the rear bracket. and a cylindrical body that extends to surround the movable contact and overlap the inner circumferential surface of the plunger in the rest position.

(Function) According to the coaxial scooter device of the present invention, when the plunger of the electromagnetic switch device is at the rest position, the exposed sliding surface of the plunger is covered by the cylindrical body extending from the rear bracket end wall, reducing brush wear. Even if powder enters the inside of the electromagnetic switch device through the opening of the rear bracket, it adheres to the inner circumferential surface of the cylindrical body or accumulates inside the plunger via the cylindrical body. Since the cylindrical body is formed in a size that surrounds the movable contact, the contact between the movable contact and the fixed contact is made within the cylindrical body, and therefore contact abrasion powder is also deposited inside the cylindrical body or inside the plunger. deposits on.

(Embodiments) Hereinafter, the coaxial starter device of the present invention will be described in more detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows a coaxial starter device 20 according to an embodiment of the present invention. Coaxial starter device 2 of this embodiment
0 is a permanent magnet 22 that is fixed at intervals in the circumferential direction on the inner circumferential surface of a yoke 21a that constitutes a magnetic circuit and forms an outer wall.
A DC motor 25 mainly consists of an armature 23 rotatably arranged in the center of a yoke 21a, and a conventional commutator 24 provided at one end of the armature 23.
including.

The armature 23 in this DC motor 25 is composed of a hollow armature rotating shaft 26 and an armature core 27 attached to the outer periphery of the rotating shaft. An output rotary wheel 28 is disposed at one end in the axial direction of the DC motor 25, that is, on the front side (right side in FIG. 1), and rotation is transmitted to the output rotary wheel 28 by a driving force transmission device (not shown). The output rotating wheel 28 is arranged on the same axis as the armature rotating shaft 26 of the DC motor 25, and one end thereof is inserted into the internal passage 26a of the armature rotating shaft 26 and has a sleeve interposed between the inner circumferential surface thereof. It is supported slidably in the axial direction via a bearing (not shown). A pinion 29 is attached to the front end of the output rotating wheel 28, and as the output rotating shaft 28 slides, the pinion 29 pops out from the front end opening 31 formed in the front machine frame 30 that houses the driving force transmission device. , meshes with the engine's ring gear (not shown).

On the other hand, a bowl-shaped rear bracket 32 made of aluminum or non-magnetic material is fitted to the rear end of the yoke of the DC electric motor 1125, and an electromagnetic switch device 42 is further attached to the rear thereof. The rear bracket 32 attached to the rear end of the DC motor 25 has an opening 3 in the center of its end wall 32a.
2b is formed, and the opening 32b is defined by a passage of a cylindrical flange portion 32c projecting inward from the DC motor.

A bearing 33 is fitted into the inner periphery of this opening 32b, and the rear end portion of the armature rotating shaft 26 is fitted into and supported by this bearing 33.

As shown in FIG. 2, inside the rear bracket 32, there is a holding part 35 that holds a plurality of brushes 34 that are in sliding contact with the commutator 24, an external terminal bolt 36 that is connected to a power source such as a battery, and the bolt 36. A brush support/terminal assembly (hereinafter simply referred to as a brush holder) 38 is disposed in which a power supply side fixed contact 37a conductive to the brush 34 and a brush side fixed contact 37b conductive to the brush 34 are integrated into a resin unit. is fixed with screws 39.

As shown in FIG. 2, this brush holder 38 includes an annular main body 40 made of resin, with a brush holding portion 35 formed on the negative side thereof, and a fixed contact 37a on the other side.
37b is formed to protrude in the axial direction so as to face a movable contact of an electromagnetic switch device which will be described later. When this brush holder 38 is fixed to the inside of the rear bracket 32 with screws 39, the inner surface of the end wall 32a of the rear bracket 32 and the other surface of the main body 40 of the brush holder 38 are in close contact with each other. Contact point 37a,
Openings or windows 41a, 41b are formed corresponding to the positions of the fixed contacts 37a, 37b such that the openings 37b protrude from the end wall 32a of the rear bracket 32 rearward, that is, toward the electromagnetic switch device 42 side. End wall 32 of rear bracket 32
A cylindrical body 32d having the same axis as the central axis of the central opening 32b is formed on the outer surface a. Although this cylindrical body 32d is formed integrally with the rear bracket 32, it may be formed separately and attached to the end wall 32a.

As is clear from FIG. 2, the peripheral wall of this cylindrical body 32d includes a window 41a formed in the end wall 32a of the rear bracket 32;
41b, so that each window 4 is
Notches 32e are formed corresponding to 1a and 41b. In addition, the axial length and size of this cylindrical body 32d (
The diameter) is very important in the present invention, but since these are related to the components of the electromagnetic switch device 42, they will be described in detail after the electromagnetic switch device 42 is explained. In addition, in FIG. 2, the reference numeral 43 indicates the electromagnetic switch device 42.
The front core, which is one component, is shown, and the core 43 is attached closely to the outer surface of the end wall 32a of the rear bracket 32, and at that time, a window 41a formed in the end wall 32a of the rear bracket 32, Each fixed contact 3 protruding from 41b
Notches 43a and 43b are formed in the core 43 in order to cause the cores 7a and 37b to protrude further rearward from the core 43.

The electromagnetic switch device 42 includes an excitation coil 46 wound around a plastic bobbin supported by front and rear cores 43 and 45 forming a magnetic path together with a case 44, and a sleeve fitted into the central opening of the bobbin. A plunger 48 having a U-shaped cross section is slidably disposed within the plunger 47, and one end is attached to the plunger 48 and the other end is connected to the armature through an opening 32b formed in the end wall 32a of the rear bracket 32. A tubular rod 49 made of non-magnetic stainless steel enters the internal passage 26a from the rear end of the rotating shaft 26, and a movable contact 5 is held on the rod 49 via an insulator 50.
1.

A push rod 52 is slidably fitted into the tubular rod 49, extends forward from the front end opening of the tubular rod 49, and has a front end formed on the end surface of the output rotating wheel 28. It faces a steel ball placed in a recessed area with a slight gap.

The rear end of the tubular rod 49 is closed, and a coil spring 54 is disposed inside the rod 49, the end of which abuts against the closed portion 53 and the end surface of the push rod 52, respectively. The coil spring 54 applies a pressing force to the pushing rod 52 as the tubular rod 49 moves, and when pulled, applies a pushing force to the output rotating shaft 28.

The reference numeral 55 indicates a coil spring for maintaining the steel ball in a predetermined position, and the reference numeral 56 indicates a tubular rod 49.
The figure shows a return spring for returning the .

By the way, in the cylindrical body 32d formed on the outer surface of the end wall 32a of the rear bracket 32 and extending rearward, as is clear from FIG. is smaller than the inner diameter of the plunger 48, and its axial length is such that it can slightly fit inside the plunger 48 when the plunger 48 is at rest.

Next, the operation of the starter device 20 described above will be briefly explained.

When the starter inch of the vehicle is closed, the electromagnetic switch device 42 is energized and the plunger 48 moves forward, and the accompanying movement of the tubular rod 49 compresses the internal coil spring 54, causing the push rod 52 to push the plunger 48 forward. Pressure is applied to cause the output rotating shaft 28 to slide forward. As a result, the pinion 29 is engaged with the ring gear of the engine, and the movable contact 51 provided on the tubular rod 49 comes into contact with the fixed contacts 37a and 37b, so that the DC motor 25 is powered on. As a result, DC motor 2
The rotational force of the armature rotating shaft 26 of No. 5 is transmitted to the output rotating shaft 28 via a driving force transmission device consisting of a planetary gear reduction device, a one-way clutch device, etc., and the engine is driven by the rotation of the pinion 29.

When the engine starts, the electromagnetic switch device 42 is de-energized, the output rotating shaft 28 is returned to its original position by a return spring provided at an appropriate position, and the engagement between the pinion and the engine ring gear is released.

During this operation, the cylindrical body 32d provided on the rear bracket 32 always covers the exposed sliding surface 47a of the sleeve 47 when the plunger 48 is at the rest position, thereby removing brush abrasion particles. is rear bracket 3
Even if it enters the electromagnetic switch device 42 through the central opening 32b of 2, it will not fall onto the sliding surface 47a mentioned above,
attached to the inside of the cylindrical body 32d or attached to the cylindrical body 32d.
d and is deposited inside the plunger 48.

Further, the contact between the movable contact 51 and the fixed contacts 37a and 37b is made inside the cylindrical body 32d, so that the contact abrasion powder generated by this also adheres and accumulates inside the cylindrical body 32d or inside the plunger 48. deposits on.

(Effects of the Invention) As explained above, according to the coaxial starter device of the present invention, a cylindrical body is formed on the outer surface of the end wall of the rear bracket to protrude into the plunger of the electromagnetic switch device, and the movable contact By making contact with the fixed contact within the diameter of the cylindrical body, brush abrasion powder and contact abrasion powder do not adhere to the plunger sliding surface, so plunger sliding failure does not occur. As a result, contact failure does not occur,
Operation of the electric motor can be guaranteed over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a coaxial starter device according to an embodiment of the present invention, and FIG. 2 is a part of the armature, a brush holder, and a rear bracket constituting the coaxial starter device. FIG. 3 is a partially cutaway front view of a conventional coaxial starter device. 20... Coaxial starter device, 25... DC motor, 26... Armature rotating shaft, 28... Output rotating shaft, 2
9... Pinion, 32... Rear bracket, 32a
... End wall, 32d... Cylindrical body, 37a, 37b...
・Fixed contact, 38... Brush support and terminal assembly, 41
a, 41b...window, 42...electromagnetic switch device, 4
6... Excitation coil, 48... Plunger, 49...
・Tubular rod, 51...Movable contact. In addition, the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A coaxial type in which an armature rotating shaft of an electric motor, an output rotating shaft having a pinion at the front end and supported so as to be slidable in the axial direction, and an electromagnetic switch device attached to the rear end of the electric motor are arranged on the same axis. In the starter device, a window for protruding a fixed contact formed in an end wall of a rear bracket attached to a rear end of a yoke of the electric motor, and a window for protruding a fixed contact formed in an end wall of the rear bracket arranged at a rear end of the electric motor. A power supply side fixed contact and a brush side fixed contact protruding into the inside of the electromagnetic switch device, an excitation coil constituting the electromagnetic switch device, a plunger having a substantially U-shaped cross section and arranged to be slidable in the axial direction inside the electromagnetic switch device; a rod that is attached to the plunger and extends along its central axis and supports a movable contact that abuts to short-circuit both of the fixed contacts;
A coaxial starter device including a cylindrical body provided on an end wall of the rear bracket and extending so as to surround the movable contact and overlap an inner circumferential surface of the plunger at a rest position.