JP2003083208A - Case structure of starter motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substantially small and simple case structure of a starter motor which makes feasible of simplifying assembling work without needing a through bolt when a motor case is formed. SOLUTION: A magnet 3 is fixed on the inside of a cylindrical yoke 2 and an armature 5 provided with a coil facing the magnet 3 is rotatably mounted to the yoke 2. Both end parts of the yoke 2 are covered with covers 11, 13 and a motor case 79 covering the outer of the armature 5 is composed of the cover 11, 12 and the yoke 2. The covers 11, 12 are fixed to the yoke 2 by a screwing structure or a press fit insertion structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter motor for an engine of a motorcycle or other vehicle.

[0002]

2. Description of the Related Art The engine is equipped with a DC motor which is supplied with power from a battery as a starter motor for starting the engine. In this starter motor, a plurality of magnets that are divided in the circumferential direction are fixed to the inner surface of a cylindrical yoke to form a stator, and an armature (rotor) is formed by a coil that is arranged so as to face this magnet. The rotating shaft of the armature is the output shaft of the motor. The crankshaft of the engine is connected to the motor output shaft via a reduction gear, an overrunning clutch, etc., and the engine is started by the rotational force of the starter motor.

Such a starter motor is required to have a small size and a simple structure in order to lay out the entire engine compactly.

FIG. 3A is a schematic side view of a starter motor using a conventional ferrite magnet, and FIG. 3B is a rear view of the starter motor shown in FIG. 3A.
As illustrated, the magnet 44 is joined to the inner surface of the cylindrical container-shaped yoke 41 having one end (front end) opened. As the magnet 44, a magnetized ferrite-based magnetic material forming a normal magnet is used. The yoke 41 and the magnet 44 form a stator. An armature 42 including a plurality of magnetic pole teeth 60 is provided so as to face the magnet 44. A coil (not shown) is wound around each magnetic pole tooth 60 serving as a core. Each magnetic pole tooth 60 is radially formed from the motor output shaft 43 which is the rotation shaft of the rotor 42.

A commutator 62 including contact pieces 61 corresponding to the magnetic pole teeth 60 is provided on the motor output shaft 43. A power supply voltage is supplied to the contact piece 61 of the commutator 62 from a power supply cable 63 via a brush (not shown). The front end of the yoke 41 is covered with a front cover 45. Front cover 4
5 is a mounting hole 45a for bolting to the engine side.
Are formed in two places, for example.

The rear end surface of the yoke 41 constitutes a rear cover 41a (integral with the yoke 41). A motor case 64 is formed by the front cover 45, the yoke 41, and the rear cover 41a integrated with the front cover 45. A through bolt 46 is inserted between the rear cover 41a and the front cover 45 to fasten the motor case 64. The through bolt 46 is inserted into the gap of the divided portion of the magnet 44 on the inner surface of the yoke 41. Since the ferrite magnet 44 has a relatively large thickness, the through bolt 46 can be inserted within the thickness range.

However, in the starter motor using the ferrite type magnet, the magnet thickness becomes large, so that the yoke outer diameter becomes large and the motor becomes large.

On the other hand, a starter motor using a high energy neodymium magnet instead of the ferrite magnet has been developed. By using this neodymium-based magnet, the thickness of the magnet can be reduced, and the output can be improved and the size can be reduced.

FIG. 4 (A) is a schematic side view of a starter motor using a conventional neodymium magnet.
(B) is a rear view of the starter motor of (A). As shown in the figure, a high energy neodymium magnet 51 made of a magnetic material containing rare earth neodymium (Nd) or a compound thereof is bonded to the inner surface of the cylindrical yoke 52.
When this neodymium magnet 51 obtains the same output,
Since it can be made thinner than the ferrite magnet 44 (FIG. 3), the outer diameter of the yoke can be reduced accordingly and the motor can be miniaturized. An armature (rotor) 65 is provided so as to face the magnet 51. The structure of the armature 65 is similar to that of the example of FIG. 3, and a commutator 67 and radial magnetic pole teeth 68 are provided on the motor output shaft 66.

The front and rear ends of the yoke 52 constituting the stator are covered with a front cover 53 and a rear cover 54. Through bolts 55 are inserted between the front cover 53 and the rear cover 54 to fasten the motor case 69 including the yoke 52 and the front and rear covers 53 and 54.

[0011]

However, in the above-mentioned conventional starter motor using the neodymium magnet, since the magnet 51 is thin, the through bolt 5 is inserted inside the yoke of the divided portion between the magnets 51 divided in the circumferential direction.
I can't pass 5. Therefore, the through bolt 55 for fixing the yoke 52 and the front and rear covers 53, 54 can only be provided outside the yoke 52. For this reason,
A flange 57 for passing the through bolt 55 is provided outside the starter motor to provide the through bolt 55. Therefore, even if the outer diameter of the yoke is reduced by using the neodymium magnet, the through bolt 55 protrudes to the outside, so that it is difficult to make the starter motor compact and simple.

Further, when forming a conventional motor case, it is necessary to fasten the front cover, the yoke, and the rear cover (in some cases, the front cover and the yoke) with through bolts, which is a troublesome process.

That is, in the example using the ferrite magnet shown in FIG. 3, since the motor case 64 is fastened by the two through bolts 46 inserted through the yoke, the motor case assembling work becomes troublesome. Further, the head of the through bolt 46 projects to the rear surface of the motor case, which may be a constraint on the layout of cables and other parts in a narrow engine room. In the example using the neodymium magnet shown in FIG. 4, two through bolts 55 are provided on the outer peripheral side of the yoke.
As described above, the size cannot be substantially reduced as described above, which becomes a constraint on the layout of other components, and the work of assembling the motor case with the bolts is troublesome. Further, in any case, since the bolt is used, the number of parts increases and the management thereof becomes complicated.

The present invention has been made in consideration of the above-mentioned prior art, and provides a case structure of a starter motor which does not require through bolts for forming a motor case, can be easily assembled, and is substantially small and simple. With the goal.

[0015]

In order to achieve the above object, according to the present invention, a magnet is fixed to the inner surface of a cylindrical yoke, and an armature having a coil facing the magnet is rotatably provided with respect to the yoke. A case structure of a starter motor comprising a cover for covering both ends of the yoke, and the cover and the yoke forming a motor case for covering an outer periphery of the armature, wherein the cover has a screw-in structure or a press-fitting insertion structure. A starter motor case structure characterized by being fixed by the structure.

According to this structure, since the cover for covering the end portion of the cylindrical yoke is connected by screw connection or press-fit insertion connection, the conventional through bolts are unnecessary, and the number of parts is reduced. The structure is simplified and the assembly work can be done easily.

A preferred configuration example is characterized in that the covers at both end portions of the yoke are both fixed by a screwing structure or a press-fitting insertion structure.

According to this structure, the covers are screwed or press-fitted into both ends of the yoke, and the motor case is assembled without using through bolts.

In another preferable configuration example, the cover at one end of the yoke is fixed by a screwing structure or a press-fitting insertion structure, and the cover at the other end is integrally formed with the yoke.

According to this structure, one end of the yoke is integrally covered with the cover, and the other end of the yoke is screwed or press-inserted to the motor case without using the through bolt. Is assembled.

[0021]

DETAILED DESCRIPTION OF THE INVENTION A starter motor according to the present invention will be described below with reference to the drawings. FIG. 1 (A) is a schematic view of a starter motor according to the present invention as viewed from the side,
(B) is a rear view of the starter motor of (A), and (C) is an enlarged view of portions a and b of (A).

This example shows an embodiment in which the case structure of the starter motor using the neodymium magnet shown in FIG. 4 is improved. The starter motor 1 according to this embodiment is
A cylindrical yoke 2 and a stator 4 composed of four magnets 3 each having an arc-shaped cross section and joined to an inner surface of the yoke 4 in a circumferential direction, and an armature (rotor) 5 mounted in the stator 4. Composed. Armature 5
Is composed of a core 7 mounted on the motor output shaft 6 so as to face the magnet 3, and a commutator (commutator) 8 mounted on the motor output shaft 6 adjacent to the core 7. The core 7 is composed of a plurality of radial magnetic pole teeth 7a, and a coil (not shown) is wound around each magnetic pole tooth 7a. The commutator 8 is composed of a number of contact pieces 8a corresponding to the magnetic pole teeth 7a, and a brush (not shown) contacts from the outer peripheral side of the commutator 8.

A front cover 11 that covers the left side of the drawing and a rear cover 12 that covers the right side of the drawing are mounted on both sides of the yoke 2. A motor case 79 is formed by the yoke 2 and the front and rear covers 11, 12. The rear cover 12 is integrally provided with a bracket 73 for mounting the motor on the engine side. A bolt mounting hole 74 is formed in the bracket 73. The motor output shaft 6 includes a front cover 11 and a rear cover 1.
2 are rotatably held by bearings (not shown). A vehicle-mounted battery (not shown) is passed through the cable (not shown) in the cable guide 16 to the front cover 11.
Is provided with a positive side terminal 72 for supplying power from the positive electrode side. The positive terminal 72 is connected to a positive brush (not shown). A brush (not shown) on the negative electrode side (earth side) that contacts the commutator 8 is grounded to the engine side from a bracket 73 of the yoke 2 and the rear cover 12 through a mounting bolt (not shown) and connected to a negative electrode of a battery (not shown). To be done.

The front cover 11, the rear cover 12, and the yoke 2
Are connected by a threaded structure. The O-ring 13 (or another gasket material) is fitted into the screw coupling portion (a portion, b portion) as shown in FIG. With such a screw-in structure, the motor case 79 can be formed without using through bolts.
The number of parts is reduced, the mounting process is omitted, and the assembly work is simplified. As a result, as shown in FIG.
On the outside of the motor case 79, neither the side face nor the rear face of the bolt 55 as in the conventional case of FIG. 4B does not project, and a simple shape can be obtained.

The screw-in structure may be a press-fit insertion structure. In the case of a press-fitting structure, it is desirable to use a fixed lock structure that rotates after the cover is press-fitted to prevent the cover from coming off.

FIG. 2A is a schematic side view of a starter motor according to another embodiment of the present invention, and FIG.
6A is a rear view of the starter motor of FIG. 7A, and FIG. This example shows an embodiment in which the case structure of the starter motor using the ferrite magnet shown in FIG. 3 is improved.

The starter motor 81 of this example has a yoke 82.
A magnet 87 is joined inside, and an armature 83 is arranged inside it. As this magnet 87, a magnetized ferrite-based magnetic material forming a normal magnet is used. The yoke 82 and the magnet 87 form a stator. A plurality of magnetic pole teeth 86 facing the magnet 87
Armature 83 consisting of.

The structure of the armature 83 is similar to that of the example of FIG. 1, and a commutator 85 and radial magnetic pole teeth 86 are provided on the motor output shaft 84. Commutator 8
A power supply voltage is supplied from the power supply cable 92 to the contact piece 91 of No. 5 via a brush (not shown). The front end of the yoke 82 is covered with a front cover 88. Mounting holes 88a for bolting to the engine side are formed in the front cover 88 at two places, for example.

The front end of the yoke 82 is open, and the rear end surface of the yoke 82 constitutes a rear cover 82a (integral with the yoke 82). A motor case 89 is formed by the front cover 88, the yoke 82, and the rear cover 82a integrated with the front cover 88. The front end portion of the yoke 82 and the front cover 88 are screwed or have a press-fitting insertion structure (screw-in structure in the figure), and an O-ring 90 is formed at the coupling part (c part) as shown in FIG.
It is assembled by mounting. By configuring the motor case 89 without using the bolts in this way, the number of parts is reduced, and as shown in FIG. 7B, the bolts do not project on the outer surface of the motor case 89 on both the side surface and the rear surface. , A simple shape can be obtained. Further, by integrating the yoke and the rear cover, the number of parts is further reduced as compared with the starter motor of FIG. 1, and the assembling work process is simplified.

[0030]

As described above, according to the present invention, the cover for covering the end portion of the cylindrical yoke is connected by the screw connection or the press-fitting insertion connection, so that the conventional through bolt becomes unnecessary, The number of parts is reduced, the structure is simplified, and the assembly work can be facilitated.

[Brief description of drawings]

FIG. 1A is a schematic view of a starter motor according to the present invention as viewed from the side, FIG. 1B is a rear view of the starter motor of FIG. 1A, and FIG. Enlarged view.

2A is a schematic view of another starter motor according to the present invention as viewed from the side, FIG. 2B is a rear view of the starter motor of FIG. 2A, and FIG. 2C is a portion c of FIG. Enlarged view.

FIG. 3A is a schematic view of a starter motor using a conventional ferrite-based magnet as viewed from the side,
(B) is a rear view of the starter motor of (A).

FIG. 4A is a schematic side view of a starter motor using a conventional neodymium magnet, and FIG.
FIG. 6A is a rear view of the starter motor shown in FIG.

[Explanation of symbols]

1: Starter motor, 2: Yoke, 3: Magnet,
4: stator, 5: armature, 6: motor output shaft,
7: core, 7a: magnetic pole teeth, 8: commutator, 8a: contact piece, 11: front cover, 12: rear cover, 13: O-ring, 16: cable guide, 41: yoke, 41a:
Rear cover, 42: armature, 43: motor output shaft,
44: magnet, 45: front cover, 45a: mounting hole,
46: through bolt, 51: magnet, 52: yoke,
53: front cover, 54: rear cover, 55: through bolt,
57: flange, 60: magnetic pole tooth, 61: contact piece, 62:
Commutator, 63: power cable, 64: motor case, 65: armature, 66: motor output shaft, 67:
Commutator, 68: magnetic pole teeth, 69: motor case, 7
2: Positive terminal, 73: Bracket, 74: Bolt mounting hole, 79: Motor case, 81: Starter motor,
82: yoke, 82a: rear cover, 83: armature, 84: motor output shaft, 85: commutator, 86:
Magnetic pole teeth, 87: magnet, 88: front cover, 88a:
Mounting hole, 89: Motor case, 90: O-ring 91:
Contact piece, 92: power cable.

Claims (3)

[Claims] A magnet is fixed to an inner surface of a cylindrical yoke, an armature having a coil facing the magnet is rotatably provided with respect to the yoke, and a cover is provided to cover both ends of the yoke. A starter motor case structure comprising a motor case that covers the outer periphery of the armature with the yoke, wherein the cover is fixed to the yoke by a screw-in structure or a press-fit insertion structure. . 2. The case structure of a starter motor according to claim 1, wherein the covers at both ends of the yoke are both fixed by a screw-in structure or a press-fitting insert structure. 3. The yoke according to claim 1, wherein a cover at one end of the yoke is fixed by a screwing structure or a press-fitting insertion structure, and a cover at the other end is integrally formed with the yoke. Starter motor case structure.