JPH01208566A - Starting motor - Google Patents

Abstract

PURPOSE:To prevent the generation of a pressure reducing action and smoothly slide a pinion moving cylinder by providing a cap on the front end portion of the pinion moving cylinder while connecting the space inside the cap to the air via an axial through hole formed on an output rotary shaft. CONSTITUTION:In a starting motor 20, an output rotary shaft 1 is provided on the armature rotary shaft 21a of a DC motor 21. A pinion moving cylinder 22 is slidably fitted on the output rotary shaft 1. On the pinion moving cylinder 22, a pinion portion 22a is provided on the front end portion, the clutch inner portion 3a of an overrunning clutch device 3 is provided on the rear end portion, and a sliding supporting face portion 22b is provided on the middle portion. In this structure, a cap 28 for covering the front end portion of the output rotary shaft 1 is provided on the front end portion of the pinion moving cylinder 22. An axial through hole 35 is formed on the output rotary shaft 1 and the inside of the cap 28 is connected to the air via the axial through hole 35.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a starting motor, and more particularly to an overhang type starting motor used for starting a vehicle engine.

(Prior Art) Conventionally, an overhang type starter motor used for starting a vehicle engine is well known, as disclosed in, for example, Japanese Utility Model Publication No. 61-6679.

In general, overhang type starter motors are
As is clear from FIGS. 2 and 3 showing the starting motor disclosed in the above-mentioned publication, there is a DC motor that generates the rotational force for starting the engine, and an armature rotating shaft extension shaft portion of this DC motor. The output rotation shaft l is slidably fitted and supported, and the front end is a pinion part 2a, and the rear end is a clutch inner part 3a of an overrunning clutch device 3. It is fully supported on the front machine frame 4 via the movable cylinder 2, and by sliding the pinion movable run 2, the front end of the pinion part 2a is attached to the front machine frame 4.
This refers to a device that can be entered and exited through an opening 5 formed in the.

In such an overhang type starting motor,
A bottomed cylindrical camp 6 having a length that covers the front end of the output rotating shaft 1 is attached to the front end of the pinion moving cylinder 2, and an annular gap 7 between the inner peripheral surface of the pinion moving cylinder and the outer peripheral surface of the output rotating shaft. The opening in the gap 7 was closed to prevent dust from entering the gap 7.

2 and 3, 8 is a ball bearing for supporting the center portion of the pinion moving cylinder 2 on the front machine frame 4, 9 is an oil seal, 10 is a sleeve bearing, and 11 is an engine ring gear.

Reference numeral 12 indicates a stopper provided at the front end of the output rotating shaft 1, respectively.

Next, the operation of this starter motor will be briefly explained.

When the overrunning clutch device 3 is moved forward (arrow 13) by a shift lever (not shown), the pinion moving cylinder 2 also integrally slides on the output rotation shaft 1, and the third
As shown in the figure, the pinion 2a comes out from the opening 5 of the front machine frame 4 and meshes with the ring gear 11. The DC motor is powered on by an electromagnetic switch device (not shown) that operates a shift lever just before the pinion 2a engages with the ring gear 11, and the output rotating shaft l, which is an extension of the armature rotating shaft, rotates. is a roller 3C from the clutch outer 3b of the overrunning clutch device 3 which is engaged with the output rotating shaft 1 by a helical spline.
This is transmitted to the clutch inner 3a, thereby rotating the pinion moving cylinder 2, and starting the engine via the pinion 2a and the ring gear 11.

When the pinion moving cylinder 2 is rotated at high speed by the engine after the engine is started and before the pinion moving cylinder returns, the clutch inner 3a of the overrunning clutch device 3 is moved to the clutch outer 3.
Since the roller 3C rotates faster than b, the meshing of both rollers 3C is released as a unidirectional rotational force transmission function of the device 3.
The clutch inner 3a idles, and as a result, the high speed rotation of the pinion moving cylinder 2 is not transmitted to the DC motor.

(Problems to be Solved by the Invention) However, in the conventional starter motor, when the pinion moving cylinder 2 is slid forward, the space volume inside the cap 6 increases rapidly (Fig. 3). When the pinion returns to the rear, it rapidly decreases, so that the space inside the cap 6 is placed under reduced pressure or increased pressure each time, and as a result, there is a problem in that the sliding movement of the pinion moving cylinder 2 is inhibited.

In order to solve this problem, it has been proposed and attempted to make a small hole in the end face of the camp 6, but when the pinion moving cylinder 2 slides forward as shown in FIG. Due to the reduced pressure caused by the increase in the volume of the internal space, dust floating in the air on the engine side is sucked in through the small hole, eventually causing the cap 6 to lose its value.

SUMMARY OF THE INVENTION The object of the present invention has been made to solve such conventional problems, and it is possible to prevent the movement of the pinion movement cylinder from being hindered even when a camp for dust intrusion is installed at the front end of the pinion movement cylinder. There is no starting motor to provide.

(Means for Solving the Problems) The present invention provides an electric motor that generates rotational force for starting an engine, and a front end that is slidably supported on an output rotation shaft extending from an armature rotation shaft of the electric motor. is a pinion portion, a rear end is a clutch inner portion of an overrunning clutch device, and an intermediate portion is a sliding support surface for a bearing provided on the front machine +9, and the output rotation shaft is configured to move the pinion. In an overhang-type starter motor supported on a front machine frame via a cylinder, a bottomed cylindrical cap is provided at the front end of the pinion moving cylinder to cover the front end of the output rotation shaft, and the The armature rotating shaft and the output rotating shaft integrated therewith are provided with an axial through hole penetrating from the front end to the rear end, and the inside of the cap is communicated with the atmosphere through the axial through hole. do.

(Function) In the starter motor of the present invention, when the pinion moving cylinder is slid forward to start the engine, the volume of the space inside the camp increases rapidly, and as a result, the space is depressurized. However, since air is sucked into the space inside the cap from the rear side through the axial through hole provided in the armature rotation shaft and the output rotation shaft integrated with it, There is virtually no decompression effect, and there is no obstruction to the movement of the pinion moving cylinder.Moreover, the cap has an axial through hole formed in the armature rotation shaft and the output rotation shaft integrated therewith. Air from the rear side of the starting motor is sucked in through the opening, and this rear air is relatively clean due to the position of the starting motor attached to the engine, so no dust will enter the camp. Furthermore, when the pinion moving tube returns to the rear, the air in the camp is exhausted from the axial through hole, so no pressurization occurs within that space, and the pinion moving tube slides smoothly. Return to the specified position.

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

FIG. 1 shows a starter motor 20 according to an embodiment of the present invention. In FIG. 1 showing this embodiment, parts that are the same as or corresponding to the components of the conventional starter motor shown in FIGS. 2 and 3 are given the same reference numerals, and the explanation thereof will be omitted.

The starter motor 20 includes a DC motor 21, the armature rotating wheel 21a of which is provided with an extended shaft portion, that is, an output rotating shaft 1 that extends forward (to the right in FIG. 1). This output rotation shaft l projects outward from an opening 5 formed in the front machine frame 4 of the starter motor 20. This extended shaft portion l is provided with an overrunning clutch device W1 adjacent to the DC motor 21.
3 is placed.

The overrunning clutch device 3 itself is already well known, and the cylindrical portion 3d integrated with the clutch outer 3b is slidable back and forth while meshing with the spline 1b formed on the output rotation shaft 1. It is fitted onto the shaft 1. Further, the clutch inner 3a is the rear end portion of the pinion moving cylinder 22 that is slidably fitted to the output rotating shaft l, and therefore the cylindrical part 3d, the overrunning clutch device 3, and the pinion moving cylinder 22 are integrated. The output rotating shaft 1 is slid to At that time, the axial acting force is applied to a shift lever whose one end is engaged with the plunger rod 23a of the electromagnetic switch device 23 attached to the machine frame 4, and whose two prongs at the other end are engaged so as to straddle the cylindrical part 3d. Granted by 24.

As described above, the rear end of the pinion moving cylinder 22 functions as the clutch inner 3a, so this rear end is conveniently referred to as a clutch inner part. On the other hand, the front end portion of the pinion moving cylinder 22 is a pinion portion having a pinion 22a formed on its outer peripheral surface. The intermediate part between this pinion part and the clutch inner part is a sliding support surface 22b, and the pinion moving cylinder 22 is fitted and fixed to the front machine frame 4 inside the opening 5 formed in the front machine frame 4. ball bearing 8
This sliding support surface 22b is fitted into the inner race of the holder so as to be slidably supported. A sliding support surface 22b that is an intermediate portion from the clutch inner portion in this pinion moving cylinder 22
The inner circumference up to is formed to have a large diameter, and a relatively large gap 25 is formed between it and the outer circumference of the output rotation shaft l.

In this gap 25, the pinion moving cylinder 22 is connected to the output rotating shaft 1.
A bearing 26 is arranged to support the bearing. This bearing 26 is mainly disposed on the rear end side of the pinion moving cylinder 22, that is, the inner peripheral part of the clutch inch part, and is fitted and fixed to the inner peripheral part, so that the output rotation shaft l
slide on top.

The inner circumferential portion of the front end of the pinion moving cylinder 22, that is, the pinion portion and a small portion of the sliding support surface 22b, is formed to have a small diameter, and a minute clearance 27 is formed between it and the outer circumferential surface of the output rotating shaft l. ing.

A bottomed cylindrical cap 28 is attached to the front end of the pinion moving cylinder 22 so as to close the front end opening. This bottomed cylindrical cap 28 is attached to the pinion moving cylinder 2.
The camp 28 has a length that covers the front end of the output rotating shaft l when the pinion moving cylinder 22 is in the rear return position, and the camp 28 has an annular projection 28a formed on the inside of the open end on the outer peripheral surface of the front end of the pinion moving cylinder 22. It is fitted into the annular groove 22e and is detachably mounted. The cap 2B is made of molded plastic, preferably nylon 4.6.

On the other hand, the rear end portion of the armature rotating shaft 21a of the DC motor 21 slightly protrudes to the outside of the starter motor 812G through an opening 30 formed in the rear machine frame 29 of the starter motor 20, and This rear machine frame 2 is rotatably supported by a bearing 32 fitted in a cylindrical flange 31 extending in the axial direction from the periphery of the opening 30 on the inner surface.
Similarly, a cylindrical flange portion 33 extending axially outward from the periphery of the opening 30 is formed on the outer surface of the opening 30, and this flange portion 33 covers the rear end portion of the armature rotating ring 21a. A metal cap 34 is press-fitted as shown in FIG.

As is clear from FIG. 1 and the above description, the armature rotating shaft 21a and the output rotating shaft 1 are one integral shaft, and for convenience, this will be simply referred to as the rotating shaft. This rotary shaft has an axial hole 35 formed in the shaft center that penetrates from the front end to the rear end, and the cap 34 attached to the rear end surface of the starter motor 20 also has an opening for the hole 35. An opening 36 is formed at a position corresponding to. As a result, the space in the cap 28 attached to the front end of the pinion moving cylinder 22, especially the space 3 at the front end of the output rotating shaft 1
7 communicates with the atmosphere on the rear end side through the axial through hole 35 of the rotating shaft.

In the starter motor of the above embodiment configured in this way, when the pinion moving cylinder 22 is slid forward to start the engine, the volume of the space 37 in the camp 2B increases rapidly, and As a result, a depressurizing effect is likely to occur in the space 37, but the axial through hole 35, which is opened by the rotating shaft,
Since air is sucked into the space 37 in the cap 28 from the rear side through the cap 28, a decompression effect in the space 37 does not substantially occur, and the movement of the pinion moving cylinder 22 is not hindered. Air from the rear side of the starter motor 20 is sucked into the cap 28 through an axial through hole formed in the rotating shaft, and the air from the rear side is relatively small due to the position of the starter motor 20 when attached to the engine. Since it is extremely clean, no dust will enter into the camp 28, and when the pinion moving cylinder 22 returns to the rear, the air inside the cap 28 is exhausted from the through hole 35.
Pressure does not occur within the space 37, and the pinion moving cylinder 2
2 slides smoothly and returns to the predetermined position.

(Effects of the Invention) As explained above, according to the starter motor of the present invention, the space inside the dustproof cap attached to the front end of the pinion moving cylinder can be used to rotate the armature rotation shaft and the output rotation integrated therewith. By communicating with the atmosphere at the rear end side of the starting motor through the axial through hole formed in the shaft, the sliding movement of the pinion moving cylinder becomes smooth, and when the pinion moving cylinder slides forward, Dust will not be sucked into the camp.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a starting motor according to an embodiment of the present invention, FIG. 2 is a sectional view showing main parts of a conventional starting motor,
FIG. 3 is a sectional view similar to FIG. 2, showing a state in which the pinion moving cylinder has slid forward in the starter motor shown in FIG. 2. DESCRIPTION OF SYMBOLS 1... Output rotating shaft, 3... Overrunning franc, 20... Starting motor, 21... DC motor, 2
1a... Armature rotating shaft, 22... Pinion moving cylinder,
28... Cap, 35... Axial through hole, 37...
...Space section. Note that the same reference numerals in each figure do not indicate the same or corresponding parts.

Claims (1)

[Claims] An electric motor that generates the rotational force for starting the engine, and an output rotating shaft extending from the armature rotating shaft of the electric motor are slidably fitted and supported, the front end is a pinion part, and the rear end is an overrunning clutch device. A pinion moving cylinder is provided as a clutch inner part and an intermediate part is a sliding support surface for a bearing provided on a front machine frame, and the output rotating shaft is supported on the front machine frame via the pinion moving cylinder. In the overhang type starter motor, a bottomed cylindrical cap is provided at the front end of the pinion moving cylinder to cover the front end of the output rotation shaft, and further, a bottomed cylindrical cap that covers the front end of the output rotation shaft is provided on the front end of the pinion moving cylinder, and A starter motor characterized in that an axial through hole is provided that penetrates from the front end to the rear end, and the inside of the cap is communicated with the atmosphere through the axial through hole.