JPH0241348Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a starter pinion for starting an engine.

(Prior art) As shown in Fig. 4, the conventional clutch inner 1 has a pinion 2 integrally molded on the axial end, and in order to ensure the thickness of the tooth bottom, the pinion 2 has a small major diameter of the tooth root. Since the circumferential diameter on the pinion 2 side is small, the ring-shaped first and second bearing bushes 6 and 7 made of sintered metal that are press-fitted into the circumferential surface of the clutch inner 1 are attached to the clutch inner 1 side. It was inserted from the open end (in the direction of the arrow). Thereafter, a shaft 8 for transmitting rotation of the starter motor is inserted into the clutch inner 1.
(For example, Japanese Patent Publication No. 40-2446) However, residual stress and mass hardening occur on the inner circumferential surface of the clutch inner 1 due to cutting, carburizing, etc. Projections 1a and 1b are formed. In some cases, the diameter dimension is such that the height A of the first protrusion 1a is smaller than the height B of the second protrusion 1b. When driving from the side opening end (in the direction of the arrow), the first bearing bushing b is compressed twice by the first and second protrusions 1a and 1b, which have become extremely hard due to carburizing and quenching. As the press-fitting pressure decreases, the outer circumferential diameter of the first bearing bush 6 becomes smaller than the circumferential diameter at the second protrusion 1b of the clutch inner 1, and comes into contact with the circumferential end surface 1C of the clutch inner 1 on the pinion 2 side. Sometimes the first bearing bush 6 moves and comes off even though it has been press-fitted, or the rotation of the shaft 8 causes the contact between the first bearing bush 6 and the inner circumferential surface of the clutch inner 1 to become loose. There have been cases where the gaps have worn out. For this purpose, a ring-shaped spacer 9 is inserted between the first and second bearing bushes 6 and 7, and the first bearing bushing is inserted between the inner peripheral end surface 1c of the clutch inner 1 and the spacer 9. 6 to prevent the first bearing bush 6 from moving and coming off.

(Problems to be Solved by the Invention) However, in the conventional device described above, the press-fitted bearing bushing is easy to move, and another member (spacer 9) is required to restrict the movement of the bearing bushing 6. The problem is that it is necessary.

(Means for solving the problem) A first inner circumferential portion, a second inner circumferential portion having a larger diameter than the first inner circumferential portion, and a first inner circumferential portion and a second inner circumferential portion. interposed between a clutch inner having a step connecting the peripheral portion and having a pinion integrally molded on the axial end thereof, a shaft to be inserted into the inner circumference of the clutch inner, and an inner circumferential surface of the clutch inner; The starter pinion is provided with ring-shaped first and second bearing bushes that are press-fitted into the first inner peripheral part and the second inner peripheral part, respectively.

(Example) An example of the present invention shown in the drawings will be described below. FIG. 1 is a view before carburizing and quenching, and is enlarged in the radial direction. The clutch inner 1 has a cylindrical shape and has a pinion 2 integrally formed at its axial end. Also, inside the clutch inner 1,
A step 3 having a height of approximately 40μ is formed. Furthermore, due to the step 3, the pinion 2 of the clutch inner 1
A first inner circumferential portion 4 is formed on the side inner circumference, and a second inner circumferential portion 5 having an inner circumferential diameter approximately 40μ larger than the inner circumferential diameter of the first inner circumferential portion 4 is formed on the inner circumference on the side opposite to the pinion 2.

Figure 2 is a diagram after carburizing and quenching.
The figure has been enlarged. Then, before carburizing and quenching, by forming a step 3 on the inner circumference of the clutch inner 1 and performing carburizing and quenching, residual stress and mass hardening occur, and the first and second protrusions 1a, 1
b is formed. However, since the step 3 is formed, the heights A and B of the first and second protrusions 1a and 1b are
, the height C of the step 3 becomes larger. Therefore, when the first bearing bush 6 is press-fitted in the direction of the arrow from the opening surface on the side opposite to the pinion 2 of the clutch inner 1, the first and second protrusions 1a and 1b are compressed, but the most at the step 3. The first
A bearing bush 6 is fixed to the first inner peripheral portion 4 of the clutch inner 1. Next, a second bearing bush 7 having the same inner diameter and outer diameter as the first bearing bush 6 is press-fitted onto the inner end surface of the clutch inner 1 opposite to the pinion 2 in the same manner as described above. And the second
The bearing bushing 7 is press-fitted into the first protrusion 1a and fixed to the second inner circumference 5. Also the first
A shaft 8 for transmitting the rotation of a starter motor (not shown) is inserted into the inner periphery of the second bearing bush 6 and the second bearing bush 7.

Therefore, by providing the step 3 on the inner circumferential surface of the clutch inner 1, the first and second bearing bushes 6 and 7 can be securely press-fitted, and for this reason, the movement of the first bearing bush 6 has been restricted in the past. The spacer that used to be used is no longer needed. Further, by eliminating this spacer, the space for storing grease for smooth rotation of the shaft 8 can be secured more than twice as much as in the past, and the sliding performance of the pinion 2 can be improved. In addition, the first and second having the same inner diameter and outer diameter
By using the bearing bushes 6 and 7, parts can be made common.

Furthermore, the end surface of the first bearing bush 6 on the side opposite to the pinion 2 is moved 1 mm closer to the side opposite to the pinion 2 than the step 3.
By talking about the above, the movement of the first bearing bushing 6 can be prevented more reliably.

In addition, a step 3 provided on the inner circumference of the clutch inner 1
The height C of the step 3 was set to be approximately 40μ, but when using the first and second bearing bushes 6 and 7 having the same outer diameter, the height C of the step 3 was set to be between approximately 30μ and approximately 50μ. is preferable.

Note that when the height C of the step 3 provided on the inner circumferential surface of the clutch inner 1 is larger than about 50μ, as shown in FIG. , the first bearing bushing 6 is press-fitted only at the second inner peripheral part 4, and the second bearing bushing 7 is press-fitted only at the second inner peripheral part 5. 2 bearing bushing 6,
7 can be more securely fixed to the inner periphery of the clutch inner 1.

(Effects of the invention) As described above, in the present invention, a step is provided on the inner circumferential surface of the clutch inner in which the pinion is integrally formed at the axial end, and the first inner circumference formed by the step and the first Since the first and second bearing bushes are press-fitted and fixed to the first inner periphery, which has a larger diameter than the inner periphery of the clutch inner 1, the first and second bearing bushes can be securely attached to the inner periphery of the clutch inner 1. It has the excellent effect of being able to be press-fitted and fixed.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view showing the essential parts of one embodiment of the starter pinion of the present invention, Fig. 2 is a half-sectional front view of the above embodiment, and Fig. 3 is another embodiment of the starter pinion of the present invention. FIG. 4 is a half-sectional front view of a conventional starter pinion. 1...clutch inner, 2...pinion, 3...
...step, 4...first inner circumference, 5...second inner circumference, 6...first bearing bush, 7...second bearing bush, 8...shaft.

Claims (1)

[Claims for Utility Model Registration] A first inner circumferential portion, a second inner circumferential portion having a larger diameter than the first inner circumferential portion, and the first inner circumferential portion and the second inner circumferential portion. a clutch inner having a step connecting the clutch inner and having a pinion integrally molded on the axial end; a shaft inserted into the inner circumference of the clutch inner; and a clutch inner interposed between the inner circumference of the clutch inner and the first A starter pinion comprising: ring-shaped first and second bearing bushes that are press-fitted into the first and second inner circumferences, respectively;