JPH02185670A - Coaxial starter - Google Patents

Abstract

PURPOSE:To prevent intrusion of brush powder into a contact chamber of an electromagnetic switch device and attachment of contact powder, etc., to the sliding surfaces of a plunger by furnishing a brush holder at the rear of a housing so as to block its rear opening, and surrounding the working space of a moving contact by a cylindrical member and the plunger. CONSTITUTION:A housing 54 is arranged so that its protrusion 54a encloses commutators 24, and brush holders 56 are installed so that a brush holder 56a is fitted in a hole 55 in housing 54. Accordingly the space accommodating the holder 56a is put in enclosed condition by the holder 56 and housing 54, so that the space accommodating the sliding parts of the brushes 25 and commutators 24, i.e., internal space of a DC motor 26, is sheltered by the housing 54 and holder 56, which prevents intrusion of brush powder into a contact chamber 57 of this electromagnetic switch device 38 concerned. Because the sliding surfaces of a plunger 43 are enclosed with a cylindrical member 58, contact powder generated by contacting of a moving contact 46 with fixed contact 33, 34 and/or wear dust produced by vibration of insulation 45 are prevented from attaching to the sliding surfaces of the plunger 43.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is a DC motor armature rotating shaft and an electromagnetic switch!
This relates to a coaxial type stylus in which the rond of the device and the output rotating shaft are arranged on the same axis.

(Prior Art) Fig. 7 is a cross-sectional view showing the configuration of a conventional coaxial starter. ing. The insertion shaft portion 4 of the output rotation shaft 4 is inserted into the internal passage 3a of the armature rotation shaft 3.
a is inserted, and is supported so as to be slidable in the axial direction by a sleeve bearing 5 that is fitted and fixed to the inner peripheral portion of the internal passage 3a.

6 is a driving force transmission device that transmits the driving force from the armature rotating shaft 3 to the output rotating shaft 4, which includes a planetary gear reduction device 7 and an overrunning clutch! al! f8.

The planetary gear reduction bag rL7 includes a sun gear 7&1 formed on the front outer periphery of the armature rotating shaft 3, and a planetary gear 7 that meshes with the sun gear 7&1.
b and the center support shaft 7C of this planetary gear 7b are fixed,
It is composed of a clutch outer 8a that constitutes a planetary gear arm, and an internal gear 7d that is formed on the inner circumference of the front bracket 9 and meshes with the planetary gear 7b. The overrunning flanch device R8 is composed of the clutch outer 8a, the clutch inner 8b, and the roller 8C interposed between them. Helical spline 4C
is fitted with a spline. A pinion 10 that meshes with a ring gear of the engine during forward movement is provided at the front end of the output rotating shaft 4.

Further, 11 is an electromagnetic switch device provided on the rear side of the DC motor 1, lla is a fixed contact thereof, 11b is a movable contact, IIC is a plunger rond, and 12 is a cover that covers the rear end.

In the coaxial starter configured in this way, the DC electric motor AL is energized by the operation of the electromagnetic switch device 11 to generate rotational force, and this rotational driving force is transmitted to the planetary gear reduction device. and is transmitted to the pinion 10 via the overrunning clutch 1arI18. Further, as the plunger rod llc of the electromagnetic switch device 11 moves forward, the output rotating shaft 4 is driven forward, and the pinion IO meshes with the ring gear of the engine, thereby starting the engine. In this case, only the pinion tot11 idles due to the action of the overrunning clutch device 8, thereby preventing reverse drive of the DC electric motor a1 from the engine side.

[Problem to be solved by the invention]

However, the above-mentioned conventional coaxial starter has only one electromagnetic switch device! Since the fixed contact 11a is provided at the rear of the engine, and the movable contact 11b and cover 12 that come into contact with the fixed contact 11a are installed, the overall length is extremely long, which causes interference with a part of the engine. was there.

In order to solve these problems, the present applicant previously applied for a coaxial starter shown in FIGS. 5 and 6. In these figures, FIG. 5 is a front view of the coaxial starter device, and the cross-sectional portion shows the electromagnetic switch portion, and FIG. 6 is an exploded perspective view of the brush portion. In FIG. 5, a coaxial starter device 20 includes a permanent magnet 22 fixed at a predetermined interval in the circumferential direction on the inner peripheral surface of a yoke 21 forming a magnetic path and forming an outer wall, and a permanent magnet 22 fixed at a predetermined interval in the circumferential direction. an armature 23 rotatably disposed in the section, and a commutator 24 provided at the rear end side of the armature 23 and having brushes 25 disposed on the circumference.
It includes a DC electric motor 4i126 mainly composed of the following, and a drive transmission aJII and an overrunning clutch device which are not shown in the cross-sectional view. The armature 23 in this DC motor 26 includes a hollow armature rotating shaft 27 and an armature core 2B integrally attached to the outer periphery of the armature rotating shaft 27.
and an armature coil 29 inserted into the armature core 28 and having its rear end connected to the commutator 24. An output rotation shaft 30 is disposed on the inside front side of the hollow armature rotation shaft 27, and a pinion 31 is provided at the front end of the output rotation wheel 30. Note that the portions that are not cut in section in FIG. 5 are the same as the configuration of the coaxial starter shown in FIG. 7, and therefore their explanation will be omitted. The brush 25 is housed in a brush holding portion 32a of a brush holder 32 made of resin.
The brush holder 32 also includes an external terminal screw 33a that connects a cable (not shown) from the power source, a power supply side fixed contact 33 that is electrically connected to this, and a fixed contact 34 that is connected to the brush 25 and will be described later. 35 is a substantially bowl-shaped housing, and a wheel support 36 for supporting the rear end of the armature rotating wheel 27 is attached to the inner peripheral surface of the housing. It is fitted and attached to the rear part of the sunshade 21, and the rear end is in contact with a core 40, which will be described later, at a protruding surface T.

Further, 37 is a screw for fastening the brush holder 32 and the housing 35 together.

Each of the fixed contacts 33 and 34 protrudes rearward from a through hole 35a provided in the housing 35, and this configuration will be described with reference to FIG. 6. In FIG. 6, reference numeral 34 denotes a fixed contact that conducts with the brush 25, which is insert-molded in the brush holder 32, and connected to the brush 25 by a lead wire (not shown). 33 is external terminal screw part 3
This is a fixed contact on the power supply side that conducts with 3a, and is similarly insert molded. Also, the mold surface M is the housing 35
The core 40, which will be described later, is in contact with the protruding surface T of the core 40, which will be described later.

A fixed contact 33.3 is provided in the through hole 3Et3 of the housing 35.
4 is inserted through the housing 35, and the contact surface is located behind the end surface of the housing 35, and is configured to face the movable contact 4G of the electromagnetic swift viT138. Further, the arrows in FIG. 6 indicate the assembly order. First, the brush holder 32 is positioned on the commutator 24, and then the housing 35 is placed over the brush holder 32, so that the fixed contacts 33 and 34 protrude rearward. It is assembled to do so.

In the electromagnetic switch W138, a core 40 forms a magnetic path together with the case 39, and an excitation coil 42 supported by a resin pobbin 41 is attached to the core 40. A plunger 43 is disposed on the inner circumferential side of the bobbin 41 so as to be slidable on its inner circumferential surface, and one end of a tubular glue rad 44 made of non-magnetic stainless steel is fixed to the plunger 43.

The other end of the rod 44 is located in the internal passage of the armature rotating shaft 27, and an insulator 45 is placed on the rod 44.
A movable contact 46 is held, and the movable contact 46 is configured to come into contact with the fixed contacts 33 and 34 as the plunger 43 moves. Further, a push rod 47 is slidably fitted inside the U-rad 44 and is pressed forward by a coil spring 4B. The push rod 47 is disposed within the armature rotating shaft 27, and its tip is connected to the output rotating wheel 30.
It abuts the wall of a recess formed at the rear end via a steel ball 49. A coil spring 50 is disposed on the outside of the push rod 47 and presses the steel ball 49 to hold it in a predetermined position. In addition, 51 is 11 electromagnetic switch device J
A non-magnetic plate covers the rear end of 38, 52 is a through bolt for fastening the above devices and parts, and 53 is a sealing member.

Next, the operation of the coaxial starter having the above configuration will be explained. When a starter switch of a vehicle (not shown) is closed, the electromagnetic switch device 38 is energized.

As a result, the plunge + 43 moves forward, the tubular rod 44 also moves, the internal coil spring 48 is compressed, and a pressing force is applied to the push rod 47, causing the output rotation shaft 3
0 is driven forward. Further, the movable contact 46 of the electromagnetic switch device 38 comes into contact with the fixed contact 33, 34 to turn on the power to the DC motor 26, and the DC motor 4i 126 generates rotational force.

This rotational driving force is transmitted to the 'ζ output rotating shaft 30 via a driving force transmission device not shown in the drawings, and the forward movement of the output rotating shaft 30 imparts a rotating force to the pinion 31 meshed with the ring gear. The engine is started. Further, after the engine is started, [when the power to the magnetic switch device 3B is cut off, the output rotating shaft 30 returns to its original position by a return spring provided at an appropriate location, and the engagement between the pinion 31 and the ring gear is released. be done.

The coaxial starter configured in this manner has the advantage that the axial length of the starter can be significantly shortened and the number of parts can be reduced, but the brush 25 to the commutator 24
Due to the sliding contact, the ordered brush easily enters the space (contact chamber) where the sliding surfaces of the movable contact 46 and the plunger 43 are located.

However, the coaxial type starter has a structure in which the housing 35 is attached to the rear side of the brush holder 32, so that the fixed contact 33 is
．． Some allowance is required for the dimensions of the through hole 35g from which the through hole 34 protrudes. Therefore, due to the movement of the plunger 43, etc., the brush is removed from the opening of the brush holder 32 through the through hole 35a.
The brush powder enters the contact chamber through the gap between the fixed contacts 33 and 34, and as a result, the intruded brush powder adheres and accumulates on the moving surface of the plunger 43) on the inner circumference of the plunger 41, causing a malfunction. There is a problem in that brush powder adheres to the contact surfaces of the movable contact 46 and the fixed contacts 33 and 34, leading to poor contact and other problems, leading to poor operation as a starter.

Further, since the through hole 35M is formed in the housing 35 having the bearing support portion of the armature rotation shaft 27, there is also a problem that the strength as a bearing is low.

These inventions were made to solve the above problems, and the first invention aims to obtain a coaxial starter that can prevent brush powder from entering the contact chamber of an electromagnetic switch device. In addition to the object of the first invention, the second invention aims to provide a coaxial starter which can prevent contact powder and the like from adhering to the sliding surface of the plunger.

(Means for Solving the Problems) A coaxial starter according to a first aspect of the invention includes a housing provided between an electric motor and an electromagnetic switch device, and a brush holding portion and a fixed contact on the electromagnetic switch device side of the housing. A brush holder is attached that closes the rear opening of the housing.

Further, the coaxial starter according to the second invention is the above-mentioned coaxial starter! In addition to the above invention, the present invention includes a cylindrical body that covers the movable contact and whose rear end is located near the inner circumference of the front end of the outer circumferential wall of the plunger with a minute gap.

(Function) In the first invention, since the internal space of the electric motor and the contact chamber of the electromagnetic switch device are divided by the brush holder, brush powder generated on the motor side does not enter the electromagnetic switch device side. .

Further, in the second invention, in addition to the first invention, since the plunger sliding surface and the operating space of the movable contact are divided by the cylindrical body and the outer peripheral wall of the plunger with a small gap, the movable contact Contact powder generated by contact between the fixed contact and the fixed contact does not enter the sliding surface of the plunger.

〔Example〕

1 and 2 are a sectional view of a main part and a perspective view of a brush portion of a coaxial starter according to an embodiment of the present invention. In these figures, 54 has an electromagnetic switch installed in its center so as to cover the commutator 24! The housing has a boss-shaped protrusion 54a that protrudes toward the t38 side, and is fitted and fixed to the rear end of the yoke 21. Projection part 5
4M is formed with a fitting hole 55 into which a brush holding portion of a brush holder, which will be described later, is fitted, and a bearing 36 is fitted on the inner peripheral side of the protruding portion 54m to support the rear end of the armature rotating shaft 27. ing. Reference numeral 56 designates a resin brush holder located on the J& side (ill magnetic switch device 38 side) of the housing 54, in which the fixed contacts 33, 34, the external terminal screw portion 33a, and the brush holding portion 56a are integrally molded. Further, 57 is a contact chamber of the electromagnetic switch device ff138 defined by the plunger 43, the sliding surface of the plunger 43, and the rear end surface of the brush holder 56. In addition, since each other structure is the same as that of the coaxial type starter shown in FIG. 5.6, the corresponding parts are designated by 11 and the explanation thereof will be omitted.

To assemble the brush portion of the coaxial starter configured in this way, first install the housing 54 so that its protrusion 54a covers the commutator 24, as shown by the arrow in FIG. 2, and then install the brush holder 56. , the brush holding portion 56a is fitted into the fitting hole 55 of the housing 54.

Therefore, the space in which the brush holding part 56a fitted into the insertion hole 55 exists is sealed by the brush holder 56 and the housing 54, and therefore the space in which the sliding contact part between the brush 25 and the commutator 24 exists, i.e. The internal space of the DC motor 26 includes a housing 54 and a brush holder 5.
6, the contact chamber 5 of the electromagnetic switch device 38
Brush powder is prevented from entering into 7.

Note that the engine starting operation of the above-mentioned coaxial type starter is the same as the conventional one, so a description thereof will be omitted here.

3 and 4 show another embodiment in which a cylindrical body is provided to cover the sliding surface of the plunger 43 from the rear end surface of the brush holder 56, that is, 58 extends rearward from the rear end surface of the brush holder 56. It is a cylindrical body formed integrally with the brush holder 56, and its rear end is approximately equal to and close to the front end of the outer peripheral wall of the plunger 43. Reference numeral 59 denotes a cover with a U-shaped cross section that is integrally attached to the plunger 43, and is formed to have a diameter slightly smaller than that of the cylindrical body 58, and whose front end slightly overlaps the rear end of the cylindrical body 58. The cover 59, the cylindrical body 58, and the plunger 4 are extended.
3, a labyrinth structure is formed between the space on the movable contact 46 side of the contact chamber 57 and the space on the plunger 4311 side.

The coaxial starter configured in this manner can prevent brush powder from entering the contact chamber 57 of the electromagnetic switch device 3B, and since the first working surface of the plunger 43) is covered with the cylindrical body 58, the movable contact 46 and fixed contact 33.34
It is possible to prevent contact powder generated by contact between the movable contact 46 and abrasion powder generated by vibration of the &i5 edge body 45 supporting the movable contact 46 from adhering to the moving surface of the plunger 43). In particular, the movable contact 46 abuts the fixed contact 33, 34,
At the moment when the plunger 43 moves in the @ direction, the contact portion is surrounded by the cover 59 and the cylindrical body 58, and the cover 59. Since the cylindrical body 58 and the outer circumferential wall of the plunger 43 overlap in the radial direction, contact abrasion powder that is generated hardly ever enters the moving surface of the plunger 43WI, and sliding failure due to adhesion of contact abrasion powder to the plunger 43FM moving surface is avoided. Occurrence can be prevented.

In the other embodiments described above, the axial positions of the rear end of the cylindrical body 58, the cover 59, and the front end of the outer circumferential wall of the plunger 43 are approximately equal; These axial lengths may be further extended.

Further, although the tubular body 58 is formed integrally with the brush holder 56, the tubular body 58 may be formed separately from the brush holder 56 and attached to the brush holder 56. It is preferable to install the cover 59 to prevent the adhesion of brush powder and the contact points of the brush.
It is also possible to omit this and configure only the cylindrical body 58.

Furthermore, in the second embodiment, the protrusion 5 of the housing 54
4. An appropriate number of reinforcing ribs may be provided between a and the outer peripheral wall to improve the strength of the housing 54.

〔Effect of the invention〕

As described above, according to the first aspect of the present invention, since the brush holder is provided on the rear side of the housing to close the rear opening of the housing, brush powder is prevented from entering the contact chamber of the electromagnetic switch device. This eliminates the risk of plunger sliding failure and contact failure. Moreover, since the housing does not require a large opening, the strength of the housing is improved, and therefore the housing can be made lighter and less expensive.

Further, in the second invention, in addition to the first invention, since the cylindrical body and the plunger are configured to surround the operating space of the movable contact, it is possible to prevent contact powder from adhering to the sliding surface of the plunger. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a coaxial starter according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a brush portion thereof, and FIG.
The figure is a cross-sectional view of a main part of another embodiment of the coaxial starter same as the above, FIG. 4 is an exploded perspective view of the brush portion thereof, and FIG. 5 is a front view showing a part of the previously applied coaxial starter in cross section. , FIG. 6 is an exploded perspective view of the brush portion, and FIG. 7 is a sectional view of a conventional coaxial star/tube. 21...Yoke, 24...Commitator, 25...
・Brush, 26... DC motor, 27... Armature rotating shaft, 30... Output rotating shaft, 31... Binion, 3
3.34... Fixed contact, 38... Electromagnetic switch device, 46... Movable contact, 54... Housing, 55...
... Fitting hole, 56... Brush holder, 56a... Brush holding part. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa 24: Commutator 25: Brush 26: DC motor 27: Armature rotation axis Figure 3 Procedure amendment (voluntary) 1. Indication of the case Patent application No. 1-1514 2. Name of the invention Coaxial type Starter 3, person making the correction 5゜ Target drawing of correction Contents of correction Figure 1 of the drawing will be corrected as shown in the attached sheet.

Claims (2)

[Claims] (1) The armature rotation shaft of the electric motor, the output rotation wheel having a pinion at the front end and capable of sliding in the axial direction, and the electromagnetic switch device attached to the rear end side of the electric motor are arranged on the same axis. A coaxial starter includes a housing disposed between the electric motor and the electromagnetic switch device, supporting the armature rotating shaft, and having a fitting hole for fitting the brush holding part, and an electromagnetic switch in the housing. The housing has a brush holding part that is attached to the device side and fits into the insertion hole of the housing on the motor side, and a fixed contact that a movable contact of the electromagnetic switch device comes into contact with on the electromagnetic switch device side. A coaxial starter equipped with a brush holder that closes the opening on the electromagnetic switch device side. (2) An armature rotating shaft of the electric motor, an output rotating shaft that has a pinion at the front end and can slide in the axial direction, and a plunger that is attached to the rear end of the electric motor and slides on the inner circumferential side of the excitation coil. In a coaxial starter in which an electromagnetic switch device and an electromagnetic switch device are disposed on the same axis, a fitting is disposed between the electric motor and the electromagnetic switch device, supports the armature rotating shaft, and is used to fit and insert a brush holding portion. A housing having an insertion hole, a brush holding portion attached to the electromagnetic switch device side of the housing, which fits into the insertion hole of the housing on the motor side, and a movable contact of the electromagnetic switch device on the electromagnetic switch device side. a brush holder that has a fixed contact that comes into contact with the brush holder and that closes the opening of the electromagnetic switch device side of the housing; A coaxial starter comprising a cylindrical body located near the inner periphery of the front end and having a minute gap in the radial direction with the outer peripheral wall.