JPS61123765A - Startor - Google Patents

Abstract

PURPOSE:To achieve accurate and uniform stopping/contacting of pinion shaft through snap ring by forming an annular groove section at the front end section of spline of tube to be transmitted with rotation of motor then fitting a snap ring in said groove section. CONSTITUTION:Upon turning on of a startor switch, a magnet switch 14 will press a pinion shaft 2 and move against a recovery spring 4. Consequently, the helical tube 2a of pinion shaft 2 will contact against a snap ring 3 fitted in an annular groove section 1d formed in the tube 1 while at the same time, the pinion 9 will gear with a ring gear at the internal-combustion engine side. While the rotation of startor motor 11 transmitted through an overrunning clutch 13 to the helical spline 1a of tube 1 is transmitted to the pinion 9 thus to start the engine. Consequently, stopping/contacting of pinion shaft 2 through snap ring 3 can be performed accurately and uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a starter for starting an internal combustion engine.

[Conventional technology]

Conventionally, there is a motor that transmits the rotation of the motor via a tube to a pinion shaft splined to this tube, and from this pinion shaft to the pinion.
For example, Nippon Denso Publication Branch Axis Reference Number 3l-031). 3 and 4 show cross-sectional views of essential parts of the tube in such a configuration.

Figure 3 shows the shape of a blank product formed by cold forging.As shown in the figure, the plate thickness at the rear part is thinner, and by punching out this thinner part 1e from the outer circumferential side as shown by the arrow. It is processed into the shape shown in Figure 4.

In FIG. 4, lb is a stamped helical spline, la is a stop surface on which the helical spline of the pinion shaft abuts and stops, and 1c is an annular ring including a stop surface 1a formed at the same time as the helical spline 1b of the tube 1 is formed. It is a groove.

[Problem that the invention seeks to solve]

However, in the above-mentioned method, punching is performed when forming the helical spline 1b of the tube 1, but as shown in FIG. In order to transmit the driving force, it is desirable that the groove width d is as small as possible.

However, in order to obtain the dimensions and shape of the groove portion 1c, the groove width d is limited, and in the conventional case, the groove width d is set to a predetermined size (for example, 2
(Ryu) was necessary. This is because when the groove width d becomes smaller, the groove IC is influenced by the helical spline 1b of the tube, causing deformation and wobbling, and the shape and dimensions of the groove 1c including the stop surface 1a become unsatisfactory. For this reason, the groove width d could not be made smaller. the result,
There is a problem that the groove width d is inevitably larger than the wire diameter of the restoring spring, and the restoring spool gets caught in the groove 1c during sliding during compression and expansion, resulting in poor sliding and failure to perform the return function.

In addition, since the tube 1 was formed by punching after cold forging, the shape accuracy of the stop surface 1a deteriorated, and the helical spline of the pinion shaft did not come into uniform contact with the stop surface 1a when the starter was driven. This causes eccentricity, which in turn causes eccentricity of the pinion, making it impossible to obtain reliable operation as a stopping surface, and causing abnormal noise and rattling due to eccentricity.

Therefore, an object of the present invention is to obtain reliable operation as a stop surface without impairing the return function of the restoring spring, and to prevent noise and rattling.

[Means for solving problems]

Therefore, in the present invention, an annular groove is formed in the front end of the helical spline punched out on the inner peripheral side of the tube, and a snap ring is fitted into this groove.

[For production]

As a result, the stop position of the spline of the shaft is determined by the snap ring fitted to the tube, and the groove is filled by the snap ring fitted to the groove to prevent the restoring spring from being caught.

〔Example〕

The present invention will be described below with reference to embodiments shown in FIGS. 1 and 2. ■ is a tube that has been surface hardened, and a helical spline 1b is formed on the inner periphery of the rear part.
The front end of the helical spline 1b has a groove 1d which is finished by cutting the inner peripheral side into an annular shape. A pinion shaft 2 has a pinion 9 attached to its tip and a helical spline 2a that meshes with the helical spline 1b of the tube 1 at its rear.

3 is a snap ring with a square cross section that is fitted into the annular groove 1d of the tube 1. Reference numeral 4 denotes a restoring spring interposed between a convex portion 5 formed in front of the helical spline 2a of the pinion shaft 2 and a step portion 6 formed on the inner periphery of the front portion of the tube 1, 7.8 and 10. are a small gear, an intermediate gear, and a large gear that transmit the driving force from the armature shaft 12 of the starter motor 11. Reference numeral 13 denotes an overrunning clutch provided inside the large gear 10, and this clutch transmits rotation in only one direction from the large gear IO to the tube 1. ■ 4 is a magnetic switch ``arranged in series with the binion 9,
This is a known device that pushes out the pinion shaft 2 when energized and forms an energization circuit for the starter motor 11.

The operation in the above configuration will be explained. When a starter switch (not shown) is closed, the pinion shaft 2 is pressed by the magnetic switch 14. The pinion shaft 2 moves to the left in FIG. 1 against the force of the restoring spring 4, and eventually the shaft spline 2a comes into contact with the snap ring 3 attached to the tube l, and the movement of the pinion shaft 2 stops and at the same time the pinion 9 and a ring gear on the internal combustion engine side (not shown) are engaged with each other. Also, the helical spline 1 of the tube 1 is connected to the helical spline 1 of the tube 1 via the overrunning clutch 13.
The rotation of the starter motor 11 transmitted to the motor a rotates the pinion 9 through the helical spline 2a of the pinion shaft 2 to start the engine. When a starter switch (not shown) is released after starting, the restoring spring 4 causes the pinion 9 and pinion shaft 2 to return to their pre-operation state.

By the way, the groove portion 1d is deformed when the groove width d is made smaller.
It can be made smaller regardless of sag. This is because the groove portion 1d is formed by cutting. In addition, the hardened part of the surface is scraped off by the cutting process, exposing the relatively soft part inside, but the relatively hard snap ring 3 that fits into the groove with high precision by the cutting process allows the pinion shaft 2 to have a helical shape. When the spline 2a comes into contact with the spline, the force can be dispersed, and a high-precision fitting without any problem in terms of strength can be obtained, and the positioning accuracy of the pinion shaft 2 can be improved.

If the groove width d can be made small, the area of the helical spline lb of the tube 1 can be obtained over a wide range, so the contact area between the helical spline 1b of the tube 1 and the helical spline 2a of the pinion shaft 2 can be increased, resulting in reliable drive. Force transmission takes place.

Furthermore, by fitting the groove 1d and the snap ring 3 with high precision, the contact area between the snap ring 3 and the spline 2a of the pinion shaft 2 can be obtained uniformly, and the eccentricity of the pinion shaft 2 and the pinion 9 can be prevented. Eccentricity can be suppressed.

In the embodiments described above, a helical spline was used as the spline and a snap ring with a square cross section was used as the snap ring, but straight splines, snap rings with a round cross section, etc. can also be used.

Further, in the above embodiment, the present invention was applied to a starter in which the engine drive pinion 9 and the magnetic switch 14 were arranged in series, but the present invention is not limited to this.
For example, as shown in FIG. 5, the present invention can be applied to a structure in which a magnetic switch 14 is arranged in parallel with the pinion 9 and the pinion 9 is not pushed out via the lever 15.

〔Effect of the invention〕

As described above, in the present invention, since the snap ring is fitted into the annular groove of the tube, there is no room for the restoring spring to enter the groove, and good sliding can be achieved. In addition, by fitting the snap ring into the groove, a uniform contact area between the snap ring and the shaft spline can be obtained, and shaft eccentricity and pinion eccentricity can be significantly suppressed, thereby reducing noise and rattling. It has the excellent effect of significantly suppressing the occurrence of this.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view showing an embodiment of the starter of the present invention, FIG. 2 is a vertical sectional view showing an enlarged main part of the tube in the starter, and FIGS. 3 and 4 are tubes in a conventional starter. FIG. 5 is a longitudinal sectional view showing the main structure before and after spline forming, respectively, and FIG. 5 is a structural diagram showing another embodiment. ■...Tube, 1b...Helical spline, I
C... Groove, 2... Pinion shaft, 2a...
Helical spline, 3...Snap ring, 4...
- Restoration spring, 9... Pinion, 11... Starter motor, 14... Magnetic switch.

Claims (1)

[Claims] A tube to which rotation of the starter motor is transmitted and has a spline formed on the rear inner circumference, a pinion shaft having a rear outer circumference formed with a spline that meshes with the spline of this tube, the front of the spline portion of the pinion shaft, and the front inner circumference of the tube. a restoring spring interposed between the pinion shaft, a magnetic switch that presses the pinion shaft in the axial direction and opens and closes an energizing circuit to the starter motor, and a pinion that is pushed out and rotated by the pinion shaft. In,
the tube has an annular groove at the spline front end;
The starter is made by fitting a snap ring etc. into this groove.