JP3680401B2 - Starter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starter for starting an engine.
[0002]
[Prior art]
As a conventional technique, for example, there is a starter disclosed in Japanese Patent Publication No. 6-31590. This starter has a shaft to which the rotational force of the starter motor is transmitted via a speed reducer, a one-way clutch that is fitted to the outer periphery of the shaft via a helical spline, and can move on the shaft integrally with the one-way clutch. The pinion gear is composed of a pinion gear provided and a magnet switch that applies a forward force to the one-way clutch via a lever, and the one-way clutch receives the forward force applied from the magnet switch and moves forward on the shaft. Can be meshed with the ring gear of the engine.
[0003]
[Problems to be solved by the invention]
However, in the above starter, the one-way clutch and the pinion gear are integrally moved on the shaft, so that the entire length of the shaft becomes long and the load point where the pinion gear meshes with the ring gear to the bearing that supports the rear end of the shaft. The distance becomes longer. For this reason, when the starter drives the engine, a mechanical loss due to bending of the shaft occurs, and the drive torque of the starter decreases. Therefore, when the mechanical loss is compensated or the required drive torque is slightly less, a means for reducing the number of teeth of the pinion gear and increasing the reduction ratio between the pinion gear and the ring gear is often used. However, if the number of teeth of the pinion gear is reduced by a certain value or more, the thickness of the pinion gear from the tooth bottom to the outer periphery of the shaft becomes thin, causing a problem that the teeth of the pinion gear are damaged. Therefore, if the required torque cannot be satisfied even by the method of reducing the number of teeth of the pinion gear, a large starter whose output is one rank higher must be used, which is disadvantageous in terms of cost and physique.
The present invention has been made based on the above circumstances, and an object thereof is to provide a starter capable of reducing mechanical loss due to bending of an output shaft.
[0004]
[Means for Solving the Problems]
In the first aspect of the present invention, the first circular rotating portion and the second circular rotating portion provided at the front portion and the rear portion of the pinion gear are supported rotatably and slidably through the bearings, respectively. As a result, since the rotation can be supported before and after the pinion gear, which is a load point when the starter drives the engine, the distance from the load point to the front and rear bearings is shortened, and the shaft (output shaft) of the pinion gear is supported. Since bending is suppressed, mechanical loss due to bending of the shaft can be reduced.
Moreover, it is not necessary to form a 2nd circular rotation part specially by making the 2nd circular rotation part provided in the rear part of the pinion gear into the outer part of a one-way clutch.
[0005]
In the invention of claim 2, the pinion gear is located in front of the front end of the shaft, and the first circular rotating portion is provided as a rotating shaft that is coaxial with the shaft. Accordingly, since the pinion gear does not need to be fitted to the outer periphery of the shaft, the pinion gear can be formed in a solid shape instead of a hollow shape, and the degree of freedom in reducing the number of teeth of the pinion gear is improved. As a result, it is possible to cope with a shortage of required torque on the engine side.
[0006]
In Claim 3, it is not necessary to form a 2nd circular rotation part specially by making the 2nd circular rotation part provided in the rear part of the pinion gear into the outer part of a one-way clutch.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, the starter of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view of the starter 1.
The starter 1 of the present embodiment includes a starter motor 2 that receives energization to generate a rotational force, a planetary gear speed reducer (described later) that reduces the rotational speed of the starter motor 2, and a starter motor 2 through the speed reducer. Via a drive shaft 3 to which rotational force is transmitted, a one-way clutch 4 fitted to the outer periphery of the drive shaft 3, a pinion gear 5 to which rotation of the drive shaft 3 is transmitted via the one-way clutch 4, and a lever 6 A forward force is applied to the pinion gear 5 and a magnet switch 7 for controlling energization of the starter motor 2 and the like.
[0008]
The starting motor 2 is a well-known DC motor including an armature 8, a fixed magnetic pole 9, a yoke 10, etc., and a motor contact (not shown) provided inside the magnet switch 7 when a key switch (not shown) is turned on. By closing, the armature 8 is rotated by power supplied from the battery.
The reduction gear includes a sun gear 11 formed on the outer periphery of the armature shaft 8 a, a plurality of planetary gears 12 that mesh with the sun gear 11, and an internal gear 13 that meshes with each planetary gear 12. The sun gear 11 transmits the rotation of the armature shaft 8a to each planetary gear 12 by rotating integrally with the armature shaft 8a. Each planetary gear 12 meshes with the sun gear 11 and the internal gear 13 and revolves while rotating on the outer periphery of the sun gear 11. The internal gear 13 is press-fitted into the inner peripheral surface of the center bearing 14 and is restricted from rotating. The center bearing 14 is fitted into a spigot portion 10a formed at the front end of the yoke 10 of the starter motor 2 and is restricted in rotation and movement in the axial direction.
[0009]
The drive shaft 3 has a helical spline 3a formed on the outer peripheral surface thereof, is arranged coaxially with the armature shaft 8a in front of the armature shaft 8a, and is axially restricted from moving to the center bearing 14 via a bearing 15. It is supported rotatably. Further, the drive shaft 3 rotatably supports the front end portion of the armature shaft 8a via a bearing 16 in a recess 3b formed in the center portion of the rear end. Further, a flange wall 3c enlarged in the outer diameter direction is provided on the outer periphery of the rear end of the drive shaft 3, and a plurality of pins 17 are fixed to the flange wall 3c by press fitting or the like. The pin 17 rotatably supports the planetary gear 12 via a bearing 18. Therefore, when each planetary gear 12 revolves around the outer periphery of the sun gear 11, the revolving force is transmitted to the flange wall 3 c through the pin 17 and the rotational force is transmitted to the drive shaft 3.
[0010]
The one-way clutch 4 is formed between an inner 20 provided integrally with the spline tube 19, an outer 21 (second circular rotating portion of the present invention) facing the outer periphery of the inner 20, and between the outer 21 and the inner 20. A roller 22 accommodated in a wedge-shaped cam chamber (not shown), a clutch cover 24 for preventing the roller 22 from popping out via a washer 23, and the like.
[0011]
The spline tube 19 is provided with a helical spline 19a that fits with the helical spline 3a of the drive shaft 3 on the inner peripheral surface thereof, and is provided so as to be movable in the axial direction on the drive shaft 3. The inner 20 is rotatably and slidably fitted to the outer periphery of the drive shaft 3 via a bearing 25 that is press-fitted into its inner periphery. When the rotation of the drive shaft 3 is transmitted to the inner 20 through the spline tube 19, the roller 22 moves in the narrow direction of the cam chamber and connects the inner 20 and the outer 21, thereby rotating the inner 20. To communicate. Further, when the rotational speed of the outer 21 is higher than that of the inner 20, the torque transmission from the outer 21 to the inner 20 is cut off by moving in a wider direction of the cam chamber and separating the outer 21 and the inner 20. The outer 21 is fitted to the inner periphery of a bearing 27 fixed to the starter housing 26, and is supported on the bearing 27 so as to be rotatable and slidable (in the axial direction).
[0012]
The pinion gear 5 is provided integrally with the outer 21 on the front side of the one-way clutch 4, and an output shaft 28 (first circular rotating portion of the present invention) that is coaxial with the drive shaft 3 is integrally formed with the front portion of the pinion gear 5. The outer peripheral surface of the tip of the output shaft 28 is supported by a bearing 29 fixed to the tip of the starter housing 26 so as to be rotatable and slidable (in the axial direction). The pinion gear 5 can mesh with a ring gear (not shown) of the engine by moving forward with respect to the drive shaft 3 together with the one-way clutch 4 and the output shaft 28. Accordingly, the output shaft 28 provided at the front portion (that is, the ring gear side) of the pinion gear 5 has an outer diameter smaller than that of the pinion gear 5 so that the output shaft 28 can rotate without interfering with the ring gear. An elastic member 30 such as a rubber plate for restricting the forward movement of the output shaft 28 is disposed between the inner surface of the front end of the starter housing 26 and the bearing 29.
[0013]
The magnet switch 7 includes a coil (not shown) that is energized when the key switch is turned on, a plunger (not shown) that is slidably disposed in the hollow interior of the coil, and the motor contact described above. When the plunger is attracted by the magnetic force, the motor contact is closed and the lever 6 is driven through the joint 31 connected to the plunger.
One end of the lever 6 is connected to the joint 31, the other end is connected to the outer periphery of the spline tube 19, and the lever 6 is provided to be swingable around a fulcrum 32 fixed to the starter housing 26.
[0014]
Next, the operation of this embodiment will be described.
When the coil in the magnet switch 7 is energized by the ON operation of the key switch and the plunger is attracted, the lever 6 connected to the joint 31 swings around the fulcrum 32. As a result, the spline tube 19 connected to the other end of the lever 6 is pushed out on the drive shaft 3 along the helical spline 3a, so that the one-way clutch 4, the pinion gear 5, and the output shaft 28 are integrated into a bearing. It moves forward (to the left in FIG. 1) while sliding along the inner circumference of 27, 29. As a result, the allowance of the output shaft 28 relative to the bearing 29 becomes larger than when the pinion gear 5 is in a stationary state (the state shown in FIG. 1).
[0015]
After the pinion gear 5 moving forward contacts the end face of the ring gear, when the motor contact in the magnet switch 7 is closed, a current flows from the battery to the starting motor 2 and a rotational force is generated in the armature 8. The rotation of the armature 8 is decelerated by the reduction gear, transmitted to the drive shaft 3, and further transmitted to the pinion gear 5 via the one-way clutch 4. As a result, the pinion gear 5 is pushed forward and completely engaged with the ring gear after the ring gear and the tooth trace coincide with each other and mesh with the ring gear while rotating at least half a pitch, thereby rotating the pinion gear 5 to the ring gear. It is transmitted to start the engine. The forward movement of the one-way clutch 4 with respect to the drive shaft 3 is restricted by the front end surface 28a of the output shaft 28 colliding with the elastic member 30. Needless to say, the impact force at the time of the collision is absorbed by the deformation of the elastic member 30.
[0016]
After the engine is started, the operation of the magnet switch 7 is stopped by turning off the key switch, and when the plunger that has been sucked up to that time returns to the initial position, the lever 6 connected to the joint 31 moves to the opposite side to that at the time of engine start. Swing. As a result, since the spline tube 19 connected to the other end of the lever 6 is retracted along the helical spline 3a on the drive shaft 3, the one-way clutch 4, the pinion gear 5, and the output shaft 28 are integrated into a bearing. While moving along the inner circumferences of 27 and 29, the pinion gear 5 moves backward (to the right in FIG. 1), and the pinion gear 5 comes off the ring gear and returns to a stationary state. Further, the motor contact in the magnet switch 7 is opened by the return of the plunger, and the energization to the starting motor 2 is stopped, whereby the rotation of the armature 8 is stopped.
[0017]
(Effect of this embodiment)
In this embodiment, the outer periphery of the output shaft 28 and the outer periphery of the outer 21 of the one-way clutch 4 are rotatably supported by bearings 27 and 29, respectively, in a state where the pinion gear 5 is engaged with the ring gear. In particular, the output shaft 28 has a larger support margin with respect to the bearing 29 than when the pinion gear 5 is stationary, and is pivotally supported at a position closer to the pinion gear 5. The distance to the bearings 27 and 29 can be shortened. For this reason, since the deflection of the output shaft 28 can be made extremely small as compared with the conventional starter, the mechanical loss due to the deflection of the output shaft 28 can be reduced, and the reduction of the driving torque can be prevented.
[0018]
In the present embodiment, the output shaft 28 is integrally provided at the front portion of the pinion gear 5, and the output shaft 28 is rotatably and slidably supported by the bearing 29. There is no need to penetrate the drive shaft 3. That is, since the pinion gear 5 can be made solid rather than hollow, the degree of freedom in reducing the number of teeth of the pinion gear 5 is improved. As a result, it is possible to cope with a shortage of required torque on the engine side to some extent.
[0019]
(Second embodiment)
FIG. 2 is a sectional view around the pinion gear 5.
The present embodiment shows an example in which the clutch cover 24 is extended to the front end side of the outer 21 and the outer peripheral surface of the clutch cover 24 is supported by a bearing 27 so as to be rotatable and slidable.
[0020]
(Third embodiment)
FIG. 3 is a cross-sectional view around the pinion gear 5.
In the present embodiment, an example in which seal members 33 and 34 are arranged at the front part of the bearing 27 and the rear part of the bearing 29 is shown. In this case, the dust-proofing effect and the sliding property of the bearings 27 and 29 can be maintained well by the seal members 33 and 34 even under conditions with poor environmental resistance where dust or water is applied.
[Brief description of the drawings]
FIG. 1 is a sectional view of a starter (first embodiment).
FIG. 2 is a sectional view around a pinion gear of a starter (second embodiment).
FIG. 3 is a sectional view around a pinion gear of a starter (third embodiment).
[Explanation of symbols]
1 Starter 2 Starter motor 3 Drive shaft (shaft)
3a Drive shaft helical spline 4 One-way clutch 5 Pinion gear 19a Spline tube helical spline 21 Outer (second circular rotating portion)
27 Bearing 28 Output shaft (first circular rotating part)
29 Bearing

Claims (2)

A shaft that is rotationally driven by a starter motor;
In a starter having a pinion gear provided on the outer periphery of the shaft so as to be able to advance and retreat along a helical spline,
A first circular rotating part and a second circular rotating part which are integrally provided at the front part and the rear part of the pinion gear and each have a circular outer periphery;
The first circular rotating part and the second circular rotating part are rotatably and slidably supported via bearings, respectively, and the second circular rotating part provided at the rear part of the pinion gear rotates the shaft. A starter that is an outer part of a one-way clutch that transmits to the pinion gear .   The pinion gear is located in front of the front end of the shaft, and the first circular rotating part provided at the front part of the pinion gear is provided as an output shaft that is coaxial with the shaft. The starter according to claim 1.

Images