JPH0510506B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reduction type starter that is composed of three axes: a motor shaft, an idle shaft, and a pinion drive shaft, and particularly relates to a reduction type starter in which an overrunning clutch is provided on the idle shaft.

In conventional three-shaft speed reduction starters in which the clutch is placed on the pinion drive shaft, the torque is large, which requires a large capacity clutch and increases weight. Furthermore, since the gear train is a single gear train, if the reduction ratio is increased, there is a problem in that the outer diameter of the clutch becomes larger.

In order to solve the above problems, the present invention provides a clutch on the shaft that is decelerated, so that the torque is small and the clutch strength is small, so the clutch can be made smaller.
Compared to the case where the clutch is placed on the motor shaft as described in the publication, the clutch rotation speed is lower, so the spring force to press the roller is small, which is effective in reducing the size of the cam chamber. Furthermore, since a two-stage reduction is provided (between the motor shaft and the clutch outer, and between the clutch inner and the drive gear), the objective is to obtain the advantage of a large degree of freedom in design, such as being able to set modules that match each torque.

The present invention will be described below with reference to embodiments shown in the drawings.

The overrunning clutch is composed of a clutch outer 2, a clutch inner 3, a roller 4, a roller spring 5, a washer 6, and a bearing 7. The overrunning clutch is rotatably supported by an idle shaft 8 consisting of a pin fixed to a housing 9. It is installed between the housing 9 and the center bearing boulder 10.

The clutch inner 3 has an inner race surface 3 that transmits torque to the clutch outer 2 through the roller 4.
a, and a gear portion 3b forming a third gear that meshes with a drive gear 12 forming a fourth gear on the outer periphery.

The clutch outer 2 has a cam chamber formed therein, and a roller 4 and a roller spring 5 are housed in the cam chamber, and are held by a washer 6. A reduction gear 2a serving as a second gear is also provided on the outer periphery of the outer 2, and meshes with a gear 1a of the motor shaft 1 serving as a first gear to transmit a reduction torque.

The drive gear 12 is on the outer periphery of the tube 13, and the tube 13 is connected to the housing 9 and the center bearing support 1 by means of bearings 14 and 15.
0 and rotates.

The shaft 16 is fitted into the tube 13 by a torsion spline and slides back and forth within the tube 13.

A pinion 17 is provided on the shaft 16 and rotates simultaneously with the shaft 16, and meshes with a ring gear 18 of the engine when the shaft 16 moves forward.

The magnet switch 19 is placed coaxially with the shaft 16, moves the shaft 16 forward, and turns on the motor switch.

M is the starter motor and Ba is the battery.

In the above configuration, the magnetic switch 19
When turned ON (ignition key ON), the plunger 20 is attracted, pushes out the shaft 16 via the rod 21 and ball 22, and engages the pinion 17 on the shaft 16 with the ring gear 18. At the same time, the contact of the motor switch turns ON, and the motor M rotates.

The rotational force of the motor M is transmitted from the motor shaft 1 via the gear 1a to the outer peripheral gear 2a of the clutch outer 2 while being reduced in speed, and is transmitted via the roller 4 to the clutch inner 3.
It is transmitted to Furthermore, the gear 3b of the clutch inner 3
Then, a second deceleration is performed between the drive gear 12 and the tube 13, which is transmitted through the helical spline engagement to the shaft 16, which rotates the pinion 17, which rotates the engaged ring gear 18 and starts the engine. start.

After the engine is started, the rotation of the ring gear 18 exceeds the rotation of the pinion 17, and the starter is turned by the engine. Here, the rotational force transmitted from the ring gear 18 to the pinion 17 is transmitted in the opposite direction from when the engine is started, but the rotational force transmitted to the clutch inner 3 is generated between the clutch inner 3 and the clutch outer 2. Due to the overrunning clutch, the power is not transmitted to the clutch outer 2 and the motor shaft 1.
To prevent damage caused by weekly rotation of motor M.

In conventional reduction type starters, the overrunning clutch is located on the driveshaft after the reduction has been completed. In this case, the clutch transmission torque is the motor torque multiplied by the reduction ratio, and the effect of the motor's moment of inertia on the clutch is the square of the reduction ratio. Therefore, a large clutch with a large capacity is required, which has the drawback of hindering weight reduction. Furthermore, in the type that uses a conventional clutch outer for the reduction gear, if the reduction ratio is increased, the outer diameter of the clutch inevitably becomes larger unless the module is made smaller at the expense of tooth strength.

Furthermore, in Japanese Patent Publication No. 58-12471, by placing the clutch directly on the motor shaft, the clutch transmission torque is reduced, the influence of the moment of inertia of the motor on the clutch is reduced, and the clutch is made smaller and weighs less. . However, since the motor of the reduction type starter rotates at a high speed exceeding 20,000 rpm, the conventional clutch does not satisfy the function of an overrunning clutch.

According to the present invention, deceleration is performed in two stages: the motor and the clutch outer, and the clutch inner and the drive gear, and the overrunning clutch is installed in the middle. By doing this, the clutch transmission torque can be reduced, and the rotational speed of the clutch can be reduced.
It is possible to make the clutch of a reduction type starter smaller and weigh more, and also to have common specifications with the clutch of a conventional type starter.

For example, the reduction ratio between the motor and clutch outer is 2, and the reduction ratio between the clutch inner and drive gear is 2.
2.5, and the total reduction ratio is 5. In this case, the clutch may be strong enough to have a reduction ratio of 2 instead of a reduction ratio of 5. The weight of the motor of a reduction type starter and a conventional type starter with the same output is smaller in the reduction type starter, so the strength of the clutch is
It will be about the same level as the conventional type. In addition, the clutch rotation speed during no-load rotation is approximately 10,000 rpm for the conventional type, and approximately 10,000 rpm for the reduction type.
At 20,000rpm, the clutch outer will be about the same as about 10,000rpm. In other words, it is possible to have common specifications for the reduction type and conventional type clutches, and the reduction type clutch can be as small as the conventional type clutch.

Furthermore, as an advantage of the present invention, since deceleration is performed at two locations, the gear ratio can be set freely.
Furthermore, the motor gear and drive gear modules can have different specifications, and the required gear strength can be easily obtained.

As described above, according to the present invention, the reduction type starter is made smaller and lighter, including a smaller and lighter clutch, common specifications with the conventional type, good responsiveness to requests for higher reduction ratios, and ease of gear design. It is a starter that has a great effect on

[Brief explanation of the drawing]

The figure is a partial cross-sectional configuration diagram showing an embodiment of the configuration of essential parts of the starter of the present invention. 1...Motor shaft, 1a...Gear, 2, 3, 4,
5, 6, 7... Clutch outer, clutch inner, roller, roller spring, washer, bearing, which constitute the overrunning clutch,
3b...Gear portion, 8...Idle shaft, 13...Tube forming the pinion drive shaft, 16...Shaft, 17...Pinion.

Claims (1)

[Scope of Claims] 1. A first gear provided on a motor shaft of an engine starting motor; and a pinion drive provided on an idle shaft disposed parallel to the motor shaft for driving the motor shaft and a pinion. a second gear that meshes with the first gear and is provided on a member of the overrunning clutch on the motor shaft side; and a second gear that is disposed between the overrunning clutch and the shaft; a third gear provided on a member on the side of the Niotsu drive shaft; and a fourth gear provided on the pinion drive shaft and meshing with the third gear; A speed reduction starter characterized in that the speed is reduced in two stages between the shaft and the idle shaft, and between the idle shaft and the pinion drive shaft, and the speed is transmitted to the pinion.