JPS5830535A - Starting device - Google Patents

Abstract

PURPOSE:To prevent load deviation generated in a starting device having an one-way clutch by a method wherein a clearance between the inner wall of a housing and the outer periphery of a clutch outer is adjusted so as to be smaller than the maximum eccentricity of the clutch outer with respect to the axial center of the clutch inner. CONSTITUTION:When an engine is started and a pinion shaft 2 as well as a clutch inner 1 have arrived at a high speed revolution, a roller 9 becomes non- contact instantaneously and a clutch outer 5 becomes eccentric a great deal. Accordingly, the load deviation is generated due to the eccentric revolution of the clutch outer 5, however, the radial clearance G between the inner wall 17 of a housing 15 and the outer periphery of the clutch outer 5 is adjusted so as to be smaller than the maximum eccentricity of the clutch outer 5, therefore, the outer periphery of the clutch outer 5 contacts with the inner wall 17 of the housing 15 and the eccentricity larger than the clearance G will never be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starter, and in particular to a starter with a speed reduction mechanism suitable for preventing the starter motor from over-rotating after the engine is started, even when installed in an engine that rapidly rotates at high speed immediately after starting. This concerns the starter.

Conventionally, the basic structure of the clutch part of a starter with a reduction mechanism that has a reduction gear on the outer periphery of the clutch outer is 1, -71 dovetail, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2. A roller and a clutch outer are placed on the outside, and the movement of the clutch outer in the radial direction is controlled by being supported by the outer periphery of the clutch inner via a metal fixed to the clutch outer side. However, in such a structure, when the pinion shaft is rotated at high speed from the engine side, the friction transmission torque of the metal part increases rapidly due to the unbalanced load on the clutch outer side (for example, centrifugal force), causing the starting motor to overspeed. This has the disadvantage that it may be damaged due to overheating.

The purpose of the present invention is to eliminate the drawbacks of the conventional technology described above.
It is an object of the present invention to provide a starter with a speed reduction mechanism capable of preventing over-rotation of a starter motor after starting an engine.

The present invention recognizes that the eccentric load on the clutch outer is caused by the eccentricity of the clutch outer and becomes maximum when the engine is rotated at high speed. This was done with a focus on the need to control the radial play between the inner wall of the housing and the outer periphery of the clutch outer, which houses the roller clutch. The present invention is characterized in that the eccentricity of the clutch outer with respect to the shaft center is less than or equal to the maximum eccentricity.

The present invention will be explained in detail below using the embodiments shown in FIGS. 1 to 3.

FIG. 1 is a partially sectional front view showing one embodiment of the starter of the present invention, and FIGS. 2 and 3 are sectional views taken along the line A--A in FIG. 1, showing different states. In FIG. 1, reference numeral 1 denotes a clutch inner, into which a pinion shaft 2 is screwed by a helical spline 3 so as to be movable in the thrust direction.

Further, a clutch outer 5 having a gear 4 integrally formed on its outer periphery is arranged on the outside of the clutch inner 1, and is formed between an inner wall 6 of the clutch outer 5 and an outer periphery 7 of the clutch inner 1. A roller 9 and a pressure spring 10 are installed in the gap 8 (Fig. 2,
(See Figure 3), clutch inner 1. , the clutch outer 5, the roller 9, and the push spring 101 constitute a one-way roller clutch.

Note that the angles formed by the tangents 11 and 12 of the contact portion between the inner wall portion 6 of the clutch outer 5 and the outer periphery 7 of the clutch inner 1 and the roller 9, respectively, form a wedge angle of 2ε. The clutch inner 1 is supported at both ends by housings 15 and 16 via ball bearings 13 and 14, respectively.

17 is an inner wall portion of the housing 15 that faces the outer periphery of the clutch outer 5, and this inner wall portion 17 and the clutch outer 5
The maximum play G in the radial direction between the outer circumferences of the clutch inner 1 is configured to be smaller than the maximum eccentricity of the clutch outer 5 when the clutch inner 1 is idling (to avoid rotation with the rotation of the engine). be. 18 is a starting motor, and a pinion gear 20 at the tip of the shaft 19 of the motor 18
Power is transmitted from to gear 4. 21 and 22 are metals for supporting the clutch outer 5 on the clutch inner 1, respectively.

In the above configuration, when the rotational force is transmitted from the starter motor 18 to the clutch outer 5 via the pinion gear 20 and the gear 4, the roller 9 forms a wedge angle 2ε as shown in FIG. Roller 9 rolls in the narrow direction of
is inserted between the clutch outer 5 and the clutch inner 1, and the three members work together to transmit rotational force to the pinion shaft 2 via the helical spline 3. At this time,
In the initial state, since the roller 9 is always pushed in the narrow direction of the gap 8 by the pressure spring 10, the clutch inner 1
The axes of the clutch outer I-5 and the clutch outer I-5 are not extremely misaligned, and the amount of eccentricity of the clutch outer I-5 is relatively small.

Next, when the engine (not shown) starts and the pinion shaft 2 and clutch inner 1 rotate at high speed, the third
As shown in the figure, the rollers 9 instantly come out of contact, and the clutch outer 5 becomes largely eccentric. Therefore, an eccentric load is generated due to the eccentric rotation of the clutch outer 5. However, in the embodiment of the present invention, the maximum radial direction G between the inner wall 17 of the housing 15 and the outer periphery of the clutch outer 5 is determined by the clutch outer 5. 5, the outer periphery of the clutch outer 5 is smaller than the maximum eccentricity of the housing 15.
contact with the inner wall portion 17, and eccentricity of 0 or more will not occur. Therefore, excessive friction transmission torque is prevented from being generated in the metal 21, 22, and braking force is generated by contact between the outer periphery of the clutch outer 5 and the inner wall 17 of the housing 15, and the friction transmitted from the clutch inner 1 side is prevented. Over-rotation of the clutch outer 5 due to the transmitted torque is prevented. Accordingly, even if the engine rotates at high speed, the starting motor 18 does not over-rotate, and damage to the armature of the motor 18 is prevented.

As described above, according to the present invention, it is possible to prevent the starting motor from over-rotating after the engine is fully engaged, and the starting motor can be prevented from being damaged.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing one embodiment of the starter of the present invention, and FIGS. 2 and 3 are A of FIG. 1 in different states.
-A cross-sectional view.

Claims (1)

[Claims] 1. It has a one-way roller clutch that prevents engine rotation from being transmitted to the starting motor after the engine is started, and a pinion shaft that moves in the thrust direction at the clutch inner diameter part of the clutch, and the outer periphery of the clutch outer of the clutch. and a pinion gear provided on the outer periphery of the shaft of the starting motor in a parallel positional relationship with the pinion shaft, which constitutes a speed reduction mechanism. A starter characterized in that a radial angle between the outer peripheral portion and the outer peripheral portion is configured to be equal to or less than a maximum eccentricity of the outer with respect to the axis of the inner.