JP3305885B2 - Commutator type rotating electric machine and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator type rotating electric machine, and more particularly to a structure of a commutator portion thereof.

[0002]

2. Description of the Related Art In recent years, as a starter for starting a vehicle engine, a reduction type starter for reducing the rotation of a rotation shaft of a starter motor by a reduction mechanism such as a planetary gear reduction mechanism and transmitting the rotation to a pinion has been developed. Has been put to practical use because the starter motor described above can be employed.

[0003]

However, the reduction ratio of the above-mentioned reduction type starter, that is, the maximum rotation speed of the starter motor is determined by the maximum permissible circumference of the commutator fitted to the rotation shaft of the starter motor. The speed is regulated by the speed, so that there is a limit to a sufficiently small and lightweight starter motor. That is, since the frictional heat sliding on the outer peripheral surface of the commutator is proportional to the peripheral speed, the temperature rise of the resin holder approaches the heat resistance limit of the resin due to the increase in the peripheral speed together with the heat generated by the resistance loss in the commutator. Further, the mechanical strength such as the centrifugal resistance of the resin holder, which increases with the square of the peripheral speed, also falls below the allowable limit.

Further, the commutator is easily peeled off from the rotating shaft due to an increase in the maximum circumferential speed of the commutator and the mechanical stress or thermal stress caused by the thermal expansion of the resin holder of the commutator. In addition, there is a problem that relative displacement easily occurs in the circumferential direction or the axial direction. The present invention has been made in view of the above problems, and prevents a temperature rise and a decrease in mechanical strength of a commutator despite an increase in the rotation speed of a starter motor. It is an object of the present invention to provide a commutator-type rotating electric machine capable of preventing relative displacement of a motor and a method for manufacturing the same.

[0005]

DISCLOSURE OF THE INVENTION The commutator type rotating electric machine according to the present invention.
The machine is provided with a rotating shaft on which an armature core is fitted, a bearing supported by an end bracket to rotatably support the rotating shaft, a cylindrical resin holder and an outer peripheral surface of the resin holder. A commutator piece having a commutator piece and fixed between the armature core and the bearing, and a brush supported by the end bracket and slidably in contact with an outer peripheral surface of the commutator ; The rotating shaft is the cylindrical resin resin.
Folder in the commutator-type rotary electric machine that have a cylindrical groove to be fixed, said rotating shaft, the axial end surface of the groove
A step surface to be formed and the bearing of the rotating shaft from the step surface
It is formed to a small diameter up to the tip of the side, and partly
The small diameter shaft portion to be formed and the bottom surface of the groove portion of the small diameter shaft portion
It is fitted to the part that does not constitute and fits into the bearing,
And a cylindrical body .

[0006]

[0007]

[Effect of the action and the Invention This onset bright commutator type rotary electric machine,
Since the resin holder of the commutator is fixed to the groove formed in the cylindrical shape on the rotating shaft, the following operation and effect can be obtained.
That is, since the commutator can be reduced in diameter by the depth of the groove formed in the cylindrical shape, the peripheral speed of the commutator can be reduced accordingly, and the centrifugal force applied to the resin holder can be reduced.
In addition, a reduction in frictional heat can reduce a rise in temperature of the resin holder and a reduction in mechanical strength due to the rise in temperature.

Further, since the resin holder is fixed to the cylindrical groove, both end surfaces of the resin holder can be joined to the cylindrical step surface facing the groove of the rotating shaft, and the joining strength between the resin holder and the rotating shaft can be improved. To improve Furthermore, since the above-mentioned step surface of the rotating shaft prohibits relative displacement in the axial direction by the resin holder of the commutator, it is possible to ultimately improve the bonding between the rotating shaft and the resin holder.

[0009]

[0010]

An embodiment of EXAMPLES rotary electric machine with a commutator of the (overall configuration) the present invention is shown in FIG. A starter motor 2 is fastened to the right end of the housing 1, and a magnet switch 3 is fastened to the housing 1 adjacent to and above the starter motor 2 in the drawing.

The right end 21b of the armature shaft (rotating shaft) 21 of the starter motor 2 is supported by an end bracket 20a via a bearing metal 4d.
The left end of the armature shaft 21 is the drive shaft 4
Is supported by the bearing 4a in the right end recess. The left end of the armature shaft 21 has a sun gear 1
9 are formed.

The drive shaft 4 extends to the left in the figure along the same axis as the armature shaft 21, and its left end is connected to the housing 1 via a bearing 4b.
The right end is supported by the center case 5 via the bearing 4c. The pinion gear 6 is helically spline-fitted on the outer periphery of the central portion of the drive shaft 4 by the helical spline groove 48 of the drive shaft 4.
A shift lever 6 is provided on a support 15 provided on the housing 1.
6 is pivotally supported, one end of the shift lever 66 is engaged with the outer periphery of the pinion 60, and the other end of the shift lever 66 is connected to the plunger 30 of the magnet switch 3. (Planetary Gear Reduction Mechanism) A flange-shaped large-diameter portion 43 is provided at the right end of the drive shaft 4, and the protruding portions of the plurality of pins 31 press-fitted into the through holes of the large-diameter portion 43 are respectively provided via bearings. The planetary gear 32 is rotatably held.

The planetary gears 32 mesh with the sun gear 19 on the small diameter side and mesh with the internal teeth 45 of the internal gear 44 on the large diameter side. Internal gear 44
Has a cylindrical shape with both ends opened with internal teeth 45 formed on the inner peripheral surface, and is arranged concentrically with the armature shaft 21. The center case 5 has a substantially bottomed cylindrical shape whose outer periphery is fixed to the housing 1, and forms a gear chamber S that houses the above-described planetary gear reduction mechanism. (One-way clutch) A cylindrical projection 51 of the center case 5 is fitted into the inner peripheral surface of the internal gear 44 and protrudes inward in the axial direction. The cylindrical projection 51 is an inner peripheral surface of the internal gear 44. And a clutch roller and a spring are accommodated between the clutch and a known one-way clutch 7. (Starter motor) The right end opening of the housing is closed by a partition wall 49 of the gear chamber S that accommodates the planetary gear reduction mechanism, and the casing 20 of the starter motor 2 is closed to the opening end of the housing by a through bolt (not shown) with the partition wall 49 interposed therebetween. Are combined.

Field poles 22 made of permanent magnets are fixed to the inner peripheral surface of the casing 20 at regular intervals in a predetermined circumferential direction. An armature core 23 is located inside the field poles 22 and is fixed to the armature shaft 21. Fixed. Armature iron core 23
The armature coil 24 is wound around a slot on the outer peripheral portion of the armature coil 24. The left end side of the armature coil 24 in the figure is a coil end portion 24a bent inward in the radial direction. Similarly, the end of the right end of the armature coil 24 bent inward in the drawing is welded to a commutator piece 81 of the commutator 8 described later. (Commutator 8) Hereinafter, the commutator 8 which is a feature of the present embodiment will be described.

A groove 25 is formed in the armature shaft 21 in a cylindrical shape and is located between the armature core 23 and the bearing 4d, so that the armature shaft 21 is fixed to a commutator having a small diameter at this portion. It is a shaft portion 21a. As in the prior art, the commutator 8 has a cylindrical resin holder 80 made of an electrically insulating resin material, and is axially extended around the outer periphery of the resin holder 80 and has an equal interval in the circumferential direction. The number of commutator pieces 81 is equal to the number of slots provided. The resin holder 80 is fixed in a state of being fitted to the commutator fixing shaft portion 21 a of the armature shaft 21 having a small diameter. The thrust washer 82 is located at a position in contact with the right end face of the resin holder 80.
Is received by the bracket 20a.

Reference numeral 9 denotes brushes, which are provided on the outer periphery of the commutator 8 at predetermined even numbers in the circumferential direction at equal intervals. Reference numeral 90 denotes a brush holder fixed to the end bracket 20a, and the brush is pressed against the commutator piece 81 by a brush spring (not shown) while being held by the brush holder 90 so as to be freely displaceable in the radial direction. Reference numeral 91 denotes a terminal for supplying power to the brush, which is fixed to the end bracket 20a while being electrically insulated.

The details of the specific manufacture of the commutator 8 will be described below with reference to FIG. In this example, A
-Diameter right side of step surface 21b of mach shaft 21
After the commutator 8 is press-fitted, the cylindrical body 21c is
The commutator 8 and the arc are pressed into the right end of the
The fitting with the matcher shaft 21 is completed. This implementation
In the example, the resin holder 80, the cylindrical body 21c and the armature
The fitting between the outer peripheral surface of the shaft 21 and the knurling fitting
If so, it is more preferable in terms of bonding.

(Operation) The operation will be described below. When the magnet switch 3 is turned on and the plunger 30 is turned on the lever 6
When the lever 6 is rotated, the lever 66 advances the pinion gear 6 toward the ring gear 61 via the pinion 60.

Immediately before the pinion gear 6 comes into contact with the ring gear 61, the starter motor 2 is started, the armature shaft 11 rotates, and the rotation is reduced through the planetary gear reduction mechanism and transmitted to the drive shaft 4. Rotates the pinion gear 6 forward through the helical spline groove 48, whereby the pinion gear 6 drives the ring gear 61.

(Effects) According to the commutator structure of the present embodiment configured as described above, the following effects can be obtained. First, since the commutator 8 can be reduced in diameter by the depth of the groove 25 formed in a cylindrical shape, the peripheral speed of the outer peripheral surface of the commutator 8 can be reduced accordingly, and the centrifugal force and resin applied to the resin holder 80 can be reduced. Commutator piece 81 that must be supported by holder 80
Can reduce the centrifugal force applied to. Further, the mechanical stress applied to the joint surface between the resin holder 80 and the commutator fixing shaft 21a and the resin holder 80 itself can be greatly reduced. What has been conventionally press-fitted is reduced by press-fitting by mold molding, so that the stress of the holder 80 is reduced.

Further, by reducing the frictional heat in proportion to the peripheral speed reduction rate, it is possible to reduce a rise in the temperature of the resin holder and a reduction in the mechanical strength due to the temperature rise. Also, the resin holder 80
Are fixed in the cylindrical groove portion 25, so that both the end surfaces of the resin holder 80 and the armature shaft 2 are reduced even though the area of the inner peripheral surface of the resin holder 80 is reduced due to the diameter reduction.
The bonding strength between the armature shaft 21 and the resin holder 80 is increased by the adhesive force due to the bonding with the annular plate-shaped step surface facing the first groove 25, and the resin holder 80 can be rotated at a high speed and started and stopped. It becomes difficult to peel off from the shaft 21.

Further, since the annular plate-shaped step surface facing the groove 25 of the armature shaft 21 regulates the axial displacement of the resin holder 80, the resin holder 80 is not displaced in the axial direction. Conventionally, in order to prevent the resin holder 80 from being relatively displaced in the axial direction with respect to the armature shaft 21, a metal member (bush) is driven between the two, but such an operation is omitted. Can be.

Since the annular plate-like stepped surface facing the groove 25 of the armature shaft 21 is in close contact with both end surfaces of the resin holder 80, the heat of the overheated resin holder 80 is transferred to the armature shaft 21 through this stepped surface. It can escape, and the rise in temperature of the resin holder 80 can be reduced. Also, the armature shaft 21b of the bearing portion
It is not necessary to reduce the diameter of the bearing metal 4d, so that the surface load of the bearing metal 4d does not excessively increase, and uneven wear of the bearing metal 4d can be prevented.

[0024]

[0025]

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing one embodiment of a commutator type rotating electric machine of the present invention.

2 is an enlarged half sectional view of the commutator portion of FIG.

[Explanation of symbols]

1 is a housing, 8 is a commutator, 9 is a brush, 20a is an end bracket, 21 is an armature shaft (rotary shaft), 23 is an armature core, 4d is a bearing metal (bearing), 80 is a resin holder, and 81 is a commutator. A piece 25 is a groove.

Claims (1)

(57) [Claims] A rotating shaft on which an armature core is fitted;
Supported by the bracket to rotate freely on the rotating shaft
Bearing, cylindrical resin holder and resin holder
The armature core having a commutator piece disposed on the outer peripheral surface of the armature
A cylindrical commutator fixed between the bearing and the bearing;
Supported by the end bracket on the outer peripheral surface of the commutator.
With a brush that slides, The rotation axis is the cylindrical shape
Has a cylindrical groove to which the resin holder is fixedCommutator type
In the rotating electric machine, the rotating shaft is, A step surface forming one axial end surface of the groove, Diameter from the step surface to the end of the rotating shaft on the bearing side
A small-diameter shaft portion that is formed small and partially forms a bottom surface of the groove portion
When, In the portion of the small diameter shaft portion that does not constitute the bottom surface of the groove portion
A cylindrical body fitted and fitted into and fixed to the bearing;  A commutator-type rotating electric machine characterized by having: