JPH09209890A - Starter with planetary gear speed reduction mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a unidirectional clutch while maintaining strength of an outer and a pin. SOLUTION: A planetary gear of a planetary gear speed reduction mechanism is supported on a pin 22 press fit in an outer 26 of a unidirectional clutch 7 through a bearing free to rotate. The pin 22 is press fit in a shaft hole 26a provided on a thick part formed between neighbouring cam chambers 30 in the circumferential direction of the outer 26, and a part (inner peripheral side) of the pin 22 is positioned on an inner peripheral side rather than a circumscribed circle B of the cam chamber 30 in a positional relation with the cam chamber 30 in the radial direction. That is, an inscribed diameter Dp of the pin 22 to be press fit in the shaft hole 26a is set to be smaller than a radius Dr from a rotational center O of the inner 25 to the circumscribed circle B of the cam chamber. Additionally, each of the pins 22 is press fit along roughly around overall width of the outer 26 in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter equipped with a planetary gear speed reduction mechanism that reduces the rotational speed of a starting motor.

[0002]

2. Description of the Related Art As a conventional technique, the Japanese Utility Model Publication No. Sho.
A deceleration type starter disclosed in Japanese Patent No. 2 is known.
This starter employs a planetary gear reduction mechanism that can set a large reduction ratio and can be coaxial, and is downsized by integrating the functions of a one-way clutch. Specifically, as shown in FIG. 5, the planetary gear 1 is mounted via a bearing 100.
By directly fixing the planetary gear shaft 120 (hereinafter referred to as a pin) that supports 10 to the outer 130 of the one-way clutch by press fitting or the like, the conventional carrier portion and the outer 130 are integrated, and the rear end of the output shaft 140 is formed. The part is configured as the inner 150 of the one-way clutch.

[0003]

However, in the planetary gear reduction mechanism, since the force acting on the pin 120 is large, the diameter of the pin 120 is increased in order to secure the strength of the pin 120, and the pin 120 is attached to the outer side. When press-fitting into 130, the press-fitting length l0 was also sufficient. Therefore, conventionally, as shown in FIG.
Since a thick wall portion is provided on the cam bottom portion and the wall thickness t0 between the cam bottom and the pin 120 is also required for strength, it is necessary to set the axial wall thickness (l0 + t0) to a large value. There was a limit to reducing the axial length and weight of the sex clutch. If you dare to shorten the axial length, as shown in Fig. 6,
By increasing the outer diameter of the outer 130 and arranging the pin 120 on the outer diameter side of the roller 160, and partially overlapping the roller 160 and the pin 120 in the axial direction (-t1), the wall thickness (l1) of the outer 130 is increased. Although the axial length can be shortened by reducing the thickness, this not only increases the outer diameter of the outer 130, but also the center distance b between the pin 120 and the sun gear 170.
As the sun gear 170 has the same specifications,
The planetary gear 110 and the internal gear must be upsized, and the starter will be upsized.

On the other hand, without increasing the outer diameter, the pin 12
As shown in FIG. 7, a roller 16 is provided as a method for shortening the axial length by setting the center distance a between the zero and the sun gear 170 to be the same.
Although it is conceivable to reduce the diameter d0 of 0, in this case, the contact surface pressure of the roller 160 with the inner 150 and the outer 130 becomes high. Therefore, it is necessary to increase the number of cams to increase the number of rollers, or to increase the length of the roller 160 to cope with the situation, and it is not possible to reduce the size in practice. Further, although the increase in the number of rollers can reduce the surface pressure between the inner 150 and the outer 130, vibration or load fluctuation from the engine during starter operation, or the inner 15
In some cases, not all rollers 160 may contribute to power transmission depending on the centering condition between 0 and the outer 130. In that case, the inner 150 and the outer 130
From the centering point, it is sufficient for the three rollers 160 to work, and the other rollers 160 repeatedly bite and release in the cam chamber (so-called flapping), which causes abnormal noise and causes the rollers 160 to move. The elastic member (for example, spring) which presses may be damaged. The present invention has been made based on the above circumstances, and an object thereof is to achieve miniaturization of a starter by miniaturizing a one-way clutch while maintaining strength of an outer and strength of a pin. .

[0005]

According to the invention of claim 1, the support shaft for supporting the planetary gear is inserted and fixed in the axial direction of the outer member to a position at least overlapping with a part of the roller. As a result, the axial insertion length into the outer can be sufficiently secured without increasing the axial thickness of the outer, so that the axial length can be shortened. Further, the support shaft has a radial positional relationship with the cam chamber, and at least a part of the support shaft is located on the inner peripheral side of the circumscribed circle of the cam chamber.
As a result, it is not necessary to increase the center-to-center distance from the center of rotation to the center of the pin even with the same roller diameter as in the conventional case, while achieving the reduction of the axial length. As a result, the axial length of the one-way clutch can be shortened without lowering the strength of the outer and support shafts, and the starter can be made smaller and lighter. The circumscribed circle of the cam chamber is the part that is farthest from the outer peripheral surface of the inner wall in the radial direction (the part where the space of the cam chamber is the largest)
Say

According to the second aspect of the present invention, the shaft hole of the outer into which the support shaft is inserted and fixed is penetrated in the axial direction, so that the workability is improved as compared with the conventional shaft hole which is a blind hole, and it is easy to perform. Can be formed.

According to the third aspect of the present invention, since the support shaft is inserted and fixed between arbitrary cam chambers adjacent to each other in the circumferential direction of the outer, the cam chamber does not interfere with the support shaft and the cam chamber. Can be expanded. Therefore, by setting the cam chambers to the minimum required three positions (thus, three rollers) that can center the inner and outer parts, it is possible to cause the fluttering of the rollers when there are four or more cam chambers. It is possible to prevent abnormal noise and damage to the elastic member that presses the roller.

According to the fourth aspect of the present invention, the roller diameter is made larger than the diameter of the support shaft as the cam chamber expands.
Since the surface pressure of the roller against the inner and outer can be reduced, it is advantageous in strength.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a starter with a planetary gear speed reduction mechanism according to the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view of a one-way clutch. As shown in FIG. 3, the starter 1 of the present embodiment includes a starter motor 3 that generates a rotational force in the armature 2 when energized, an output shaft 5 in which a pinion gear 4 is fitted on the shaft, and a rotation speed of the starter motor 3. The planetary gear speed reduction mechanism 6 (which will be described later) that reduces the speed, the one-way clutch 7 (which will be described later) that transmits a rotational force from the speed reduction mechanism 6 to the output shaft 5, and the energization control of the starting motor 3 are performed, and the pinion gear 4 is also used. It is composed of a magnet switch 8 and the like for generating the pushing force of.

The starting motor 3 is a well-known DC motor, and in addition to the armature 2, fixed magnetic poles (pole core 9 and field coil 1) arranged on the outer periphery of the armature 2.
0), which is composed of a cylindrical yoke 11 for fixing the fixed magnetic pole to the inner peripheral surface thereof, etc., and a starter switch (not shown) is turned on to close a motor contact (not shown) built in the magnet switch 8 to close the armature. 2 is energized and rotates. A permanent magnet can also be used as the fixed magnetic pole.

The output shaft 5 is located in front of the starting motor 3 (see FIG. 3).
Is arranged on the same axis as the armature shaft 2a on the right side of FIG. 1), and its tip end is rotatably supported by the front housing 13 via the bearing 12. A hollow cylindrical recess is formed in the center of the rear end of the output shaft 5, and the tip of the armature shaft 2a is rotatably supported in the recess via a bearing 14. A helical spline 5b is formed on the outer periphery of the output shaft 5, and the helical spline 5b is formed.
The spline tube 15 that is integrally provided with the pinion gear 4 is fitted therein.

The pinion gear 4 meshes with the ring gear 16 of the engine to apply the rotational force of the starting motor 3 to the ring gear 1.
6, and is provided integrally with the spline tube 15 on the output shaft 5 so as to be able to move forward and backward along the helical spline 5b. However, the forward movement of the pinion gear 4 is regulated by contacting a stop collar 17 attached to the outer periphery of the output shaft 5 near the tip. Stop collar 17
Is restricted from moving in the axial direction via a snap ring 18 that fits in a circumferential groove 5c formed on the outer circumference of the output shaft 5.

As shown in FIG. 2, the planetary gear speed reduction mechanism 6 (hereinafter referred to as a speed reducer) has a sun gear 19 formed on the outer periphery of the tip end portion of the armature shaft 2a.
9, a plurality of planetary gears 20 meshing with each other, and each planetary gear 2
It is composed of an internal gear 21 (see FIG. 3) in which 0 meshes. The sun gear 19 transmits the rotation of the armature shaft 2a to each planet gear 20 by rotating integrally with the armature shaft 2a. Each planetary gear 20 has a bearing 23 on the outer circumference of a pin 22 (support shaft of the present invention) inserted and fixed into the outer 26 of the one-way clutch 7 by press fitting.
Is rotatably supported via the sun gear 1 and the internal gear 21 while rotating to rotate the sun gear 1
Revolve around the outer circumference of 9. Therefore, when each planetary gear 20 revolves around the outer periphery of the sun gear 19, the revolving force is transmitted to the outer 26 through the pin 22, so that the outer 26 rotates. The internal gear 21 is non-rotatably fixed to the inner peripheral surface of a center bearing 24 sandwiched between the front housing 13 and the yoke 11 by press fitting or the like.

As shown in FIG. 1, the one-way clutch 7 is composed of an inner 25, an outer 26, a roller 27, a spring 28, and a clutch cover 29 (see FIG. 2). The inner 25 is provided with the rear end portion of the output shaft 5 enlarged in the radial direction, and rotates together with the output shaft 5. The outer 26 is arranged on the outer periphery of the inner 25 to form a plurality of wedge-shaped cam chambers 30 in the circumferential direction with the outer peripheral surface of the inner 25, and a spring chamber 31 continuous to the cam chamber 30. Has been done. This outer 26
When each planetary gear 20 revolves around the sun gear 19, the planetary gears 20 rotate together with the revolution of each planetary gear 20. Roller 2
7 is provided in a columnar shape and is housed in the cam chamber 30. The spring 28 is the spring chamber 3 of the outer 26.
1, the roller 27 is biased toward the narrow side of the cam chamber 30 (counterclockwise rotation direction in FIG. 1). As shown in FIG. 2, the clutch cover 29 is arranged on the speed reducer side of the roller 27 and regulates the movement of the roller 27 in the axial direction.
In addition, the movement of the roller 27 to the side opposite to the speed reducer is performed by the outer 2
It is regulated by a plate 32 (see FIG. 2) provided integrally with the plate 6.

Here, the pin 2 that supports each planetary gear 20
The relationship between 2 and the outer 26 will be described. Each pin 22
1, is press-fitted into a shaft hole 26a provided in a thick portion formed between the cam chambers 30 adjacent to each other in the circumferential direction of the outer 26, and the In the positional relationship, part of the pin 22 (inner peripheral side) is located on the inner peripheral side of the circumscribed circle B of the cam chamber 30. That is, the inner 25
The inscribed diameter Dp of the pin 22 press-fitted into the shaft hole 26a is smaller than the radius Dr from the rotation center O to the circumscribed circle B of the cam chamber 30 (see FIGS. 1 and 2). The circumscribing circle B of the cam chamber 30 refers to a circle circumscribing the portion farthest from the outer peripheral surface of the inner 25 in the radial direction (the portion where the space of the cam chamber 30 is the largest). Further, as shown in FIG. 2, each pin 22 is press-fitted in substantially the entire width of the outer 26 in the axial direction. Therefore, the shaft hole 26a formed in the outer 26 is opened so as to penetrate the entire width of the outer 26 (width in the left-right direction in FIG. 2).

When the starter switch is turned on, the magnet switch 8 energizes a built-in coil (not shown) to generate a magnetic force, so that a plunger (not shown) arranged inside the coil is provided. While sucking and closing the motor contact, the lever 33 is driven by the plunger suction force. The lever 33 engages with the groove 15a formed on the outer periphery of the spline tube 15, transmits the plunger attraction force of the magnet switch 8 to the spline tube 15, and pushes the spline tube 15 forward together with the pinion gear 4. .

Next, the operation of this embodiment will be described. When the starter switch is turned on, the motor contact of the magnet switch 8 is closed and the armature 2 is energized, so that a rotational force is generated in the armature 2. As a result, the sun gear 19 rotates together with the armature shaft 2a to rotationally drive each planetary gear 20. Each planetary gear 20 meshes with the internal gear 21 together with the sun gear 19, but the internal gear 21 is
It is fixed to 4 and cannot rotate, so each planet gear 20
Revolves around the pin 22 while revolving around the outer circumference of the sun gear 19. This revolution force is applied to the outer 2 through the pin 22.
6, the outer 26 rotates with the revolution of each planetary gear 20. When the outer 26 rotates, the roller 27 moves toward the narrower side of the cam chamber 30 and connects the outer 26 and the inner 25, whereby the rotation of the outer 26 is transmitted to the inner 25 and the output shaft 5 rotates.

On the other hand, when the plunger attraction force of the magnet switch 8 is transmitted to the spline tube 15 via the lever 33, the pinion gear 4 moves to the spline tube 1.
5, it is pushed forward on the output shaft 5 along the helical spline 5b, meshes with the ring gear 16, and transmits the rotational force of the starting motor 3 to the ring gear 16. When the ring gear 16 rotates and the engine starts, the rotation of the engine rotates the pinion gear 4, so that the rotation of the output shaft 5 (that is, the rotation of the inner 25) becomes faster than the rotation of the outer 26. The roller 27 moves toward the wider side of the cam chamber 30 due to the relative rotation difference with the inner chamber 2.
By separating 5 and the outer 26, the rotational force is not transmitted from the inner 25 to the outer 26, and the overrun of the armature 2 can be prevented. After the engine is started, when the starter switch is turned off and the operation of the magnet switch 8 is stopped, the starter motor 3 is de-energized, the rotation of the armature 2 is stopped, and the pinion gear 4 is integrated with the spline tube 15 in the output shaft 5. It retreats above along the helical spline 5b and returns to the stationary position (the position shown in FIG. 3).

(Effect of this embodiment) In this embodiment, since the pin 22 supporting the planetary gear 20 is press-fitted over substantially the entire width of the outer 26, the thickness of the outer 26 in the axial direction should be increased. Since the axial press-fit length to the outer 26 can be sufficiently secured, the axial length of the one-way clutch 7 can be shortened. Further, in the radial direction of the outer 26, a part of the pin 22 can be located on the inner peripheral side of the circumscribing circle B of the cam chamber 30 (Dr> Dp). It is not necessary to change the center distance between the pin 22 and the pin 22. As a result, the axial length of the one-way clutch 7 can be shortened without reducing the strength of the outer 26 and the pin 22, and the starter 1 can be made smaller and lighter.

Further, by press-fitting the pin 22 between the cam chambers 30 adjacent to each other in the circumferential direction of the outer 26, the cam chamber 30 can be enlarged without interfering with the pin 22. As a result, the diameter of the roller 27 housed in the cam chamber 30 can be increased, so that the roller 27
The surface pressure of the outer 26 and the inner 25 can be reduced. Further, it is possible to reduce the number of rollers 27 as the surface pressure is reduced, and it is possible to reduce the number of parts of the rollers 27 and the springs 28 while maintaining the strength. actually,
It is also possible to use the minimum required three rollers 27 that can center the inner 25 and the outer 26. This allows
It is possible to maintain strength with the minimum necessary number and achieve a stable clutch action.

Since the shaft hole 26a provided in the outer 26 does not interfere with the cam chamber 30 and the spring chamber 31, it is not necessary to form a blind hole as in the conventional case, and the outer hole 26a can be opened through the entire width of the outer 26. You can In blind hole processing,
It is necessary to process while paying attention to the depth dimension of the hole,
If it is a through hole, it is not necessary and the workability is improved. In addition, the length of the pin 22 that supports the planetary gear 20 is set to the outer 2
It is possible to achieve further weight reduction by setting the length so that the strength can be secured (for example, the same length as the conventional one) instead of the full width of 6.

(Second Embodiment) FIG. 4 shows a one-way clutch 7.
FIG. In the outer 26, when the roller 27 moves to the end point side (narrower side) of the cam chamber 30, the largest stress concentrates on the C portion and the D portion in FIG. Therefore, the outer 2
By providing the position of the pin 22 that is press-fitted in 6 on the outer diameter side of the spring chamber 31 between the C portion and the D portion, the pin 22 can be installed without significantly reducing the strength of the outer 26. In this case, since the spring chamber 31 is narrower than the cam chamber 30 in the radial direction, the spring chamber 31
Even if the shaft hole 26a is opened on the outer diameter side, the part of the pin 22 can be located on the inner peripheral side of the circumscribed circle B of the cam chamber 30.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a one-way clutch.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of a starter.

FIG. 4 is a sectional view of a one-way clutch (second embodiment).

FIG. 5 is a cross-sectional view showing a positional relationship between a pin and an outer (conventional example).

FIG. 6 is a cross-sectional view showing a positional relationship between a pin and an outer (conventional example).

FIG. 7 is a cross-sectional view showing a positional relationship between a pin and an outer (conventional example).

[Explanation of symbols]

 1 Starter 3 Starter Motor 4 Pinion Gear 5 Output Shaft 6 Planetary Gear Reduction Mechanism 7 Unidirectional Clutch 22 Pin (Support Shaft) 25 Inner 26 Outer 26a Shaft Hole 27 Roller 30 Cam Chamber B Circumscribing Circle of Cam Chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuhiro Murata 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (4)

[Claims] 1. An output shaft having a pinion gear fitted on the shaft, a planetary gear speed reduction mechanism for reducing the rotational speed of a starter motor, an inner fixed or integral with the output shaft, and an outer peripheral surface of the inner. And a one-way clutch configured to form a plurality of wedge-shaped cam chambers in the circumferential direction between them, and a roller housed in the cam chambers, for transmitting a rotational force from the planetary gear reduction mechanism to the output shaft. A support shaft rotatably supporting the planetary gears of the planetary gear reduction mechanism is fixed to the outer by press fitting, the support shafts being adjacent to each other in the circumferential direction of the cam chambers. Between the rollers, at least a part of the supporting shaft is inserted and fixed in the axial direction to a position overlapping at least a part of the roller, and at least a part of the support shaft is a circumscribed circle of the cam chamber in a radial positional relationship with the cam chamber. A starter with a planetary gear speed reduction mechanism, which is located on the inner circumference side of the gear. 2. The planetary gear speed reducer according to claim 1, wherein the outer has an axial hole into which the support shaft is inserted and fixed, and the axial hole penetrates the outer in the axial direction. Starter with mechanism. 3. The starter with a planetary gear reduction mechanism according to claim 1, wherein the cam chambers are provided at three locations in a circumferential direction. 4. The diameter of the roller is set to be larger than the diameter of the support shaft.
3. A starter with a planetary gear speed reduction mechanism according to any one of 3 above.