JPH09280145A - Planetary gear decelerating type starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the module and the decelerate ratio of the gear of a planetary gear decelerating device to specified values so as to further miniaturize the device and its weight by providing a first impact buffer device for suppressing impacts produced when a pinion is engaged with a ring gear and a second impact buffer device for suppressing impacts produced during clanking. SOLUTION: When engaging impacts occur during engaging between a ring gear and a pinion 65, since the size of reaction torque transmitted to an internal gear 44 is set lower than the permissible bending strength of the gear, which is necessary for going over a recessed and projecting fitting part 7, the internal gear 44 is rotated, the impacts are cut to be lower than the gear permissible bending strength and converted into friction heat in the recessed and projecting fitting part 7. Friction forces produced in diameter and peripheral directions are absorbed by the twisting or deformation of the cylindrical part of the internal gear 44, and thus repeated impact forces reaching inner teeth 45 during clanking are reduced. Thus, since two forms of impact absorption are realized, a module ratio is set lower than 1 and a speed reducing ratio is set over 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear reduction type starter for starting an internal combustion engine for a vehicle.

[0002]

2. Description of the Related Art In recent years, in vehicles, due to higher density in the engine room, lower fuel consumption, etc.
The use of planetary gear reduction starters, which are small and lightweight, is increasing. Here, looking at the planetary gear reduction type starter, there is a means for further increasing the reduction ratio as a means for further downsizing, but when realizing this with a planetary gear reduction device, while avoiding undercut of the gear, In order to fit within the limited same space (diameter D of the internal gear) (see FIG. 7), it is necessary to make the module (M) small as shown in FIG.

[0003]

However, the relationship between the module (M) and the tooth root stress σ _b of the gear is expressed by the following equation: σ _b = P / (M · b · y) where y = (Cos α · φ ² ) / (cos ω · 6 ψ) P: Total load applied to the addendum by the transmission torque M: Module b: Gear width α: Pressure angle φ: Tooth thickness at the root / M ω: Line of action of load P And the perpendicular of the tooth profile center line ψ: The distance from the tooth root to the intersection of the action line of the load P and the tooth profile center line / M.

As is clear from the above equation, when the module (M) is made small, the stress σ _b generated at the tooth base becomes large, and the tooth is damaged by the impact at the time of engagement shown in FIG.
The tooth may be damaged due to fatigue caused by repeated impacts during cranking. In particular, this tendency is remarkable in the sun gear of the planetary gear speed reducer. For this reason, the module (M) applied to the planetary gear speed reducer is actually used.
As disclosed in Japanese Patent Laid-Open No. 2-238171,
M = 1.25 or more and reduction ratio = 5.45 or less are the current general values. Therefore, the module (M) cannot be made small, and as a result, there is a limit to downsizing the planetary gear reduction type starter.

Regarding the speed reduction ratio of the planetary gear speed reducer in the planetary gear speed reducer starter, it has been described that the speed reduction ratio is set to 6 to 9.5 by the compound planetary gear speed reducer using multi-stage speed reduction. (JP-A-6-159205
However, because of the compound planetary gear reduction device using multi-stage reduction, it has not been possible to pursue miniaturization and weight reduction.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional planetary gear speed reduction type starter, reduces the module M to 1 or less, and realizes a reduction ratio of 6 or more, thereby further improving the planetary gear speed reduction type starter. It is designed to be compact and lightweight.

[0007]

The planetary gear reduction type starter of the present invention employs the following technical means. According to a first aspect of the present invention, in a planetary gear speed reducer including one stage, the module (M) is less than 1, and a first shock absorber for suppressing an excessive shock generated when the pinion and the ring gear mesh with each other, By using the second shock absorbing device that suppresses the repeated stress during cranking together, the reduction ratio can be set to 6 or more, and the planetary gear reduction starter can be further reduced in size and weight. .

According to the second aspect of the present invention, the first shock absorbing device reduces the meshing shock between the pinion and the ring gear by suppressing the rotation of the starter motor when the pinion meshes with the ring gear of the engine. be able to.
In the means of the third aspect, the second shock absorbing device can absorb the repeated stress at the time of cranking by the rotation or bending of the internal gear of the planetary gear speed reducer.

[0009]

1 shows an embodiment of a planetary gear speed reduction type starter according to the present invention. A starter motor 2 is fastened to the right end of the housing 1, and a magnet switch 3 is fastened to the housing 1 adjacent to the upper side of the starter motor 2 in the figure.

Armature shaft 1 of starter motor 2
1 has a right end portion axially supported by an end bracket (not shown) of the starter motor 2, and a small diameter portion 11 at a left end of an armature shaft (rotating shaft of the starter motor 2) 11.
A is supported by a bearing 4a in the right end recess of the drive shaft 4. Reference numeral 12 is a yoke of the starter motor 2. The left end portion of the armature shaft 11 has a large-diameter portion 11b having a sun gear 19 formed on the outer periphery and a large-diameter portion 11b.
The small diameter portion 11a further protruding from the above.

The drive shaft 4 extends leftward in the figure along the same axis as the armature shaft 11, and its left end portion is connected to the housing 1 via a bearing 4b.
The right end portion is supported by the center case 5 via the bearing 4c. A spline tube 60 is connected to the outer periphery of the central portion of the drive shaft 4 by a helical spline, and the spline tube 60 includes a clutch outer 62, a roller 63, and a clutch inner 64 that form a one-way clutch 6. , And the pinion 65. On the other hand, a shift lever 66 is pivotally supported on a swing support portion 15 provided in the housing 1, one end of the shift lever 66 engages with the outer circumference of the spline tube 60, and the other end of the shift lever 66 is a magnet. Plunger 30 for switch 3
It is connected to.

Next, the planetary gear speed reduction mechanism will be described with reference to FIGS. 1 and 2. A flange-shaped large-diameter portion 43 is provided at the right end of the drive shaft 4, and the projecting portions of the plurality of pins 31 press-fitted into the through-holes of the large-diameter portion allow the planetary gear 30 to rotate via bearings. keeping. These planetary gears 30 (the number of teeth Zp = 22) mesh with the sun gear 19 (the number of teeth Zs = 8) on the smaller diameter side and the internal gear 44 (the number of teeth Zi = 52) on the larger diameter side. Internal tooth 4
A gear reduction ratio of 7.5 is realized by meshing with No. 5 and setting the module to M = 0.9 (see FIG. 6).

The internal gear 44 has internal teeth 4 on its inner peripheral surface.
It has a cylindrical shape with openings 5 at both ends and is arranged concentrically with the armature shaft 11. The center case 5 described above has a substantially bottomed cylindrical shape whose outer periphery is fixed to the housing 1, and forms a gear chamber that houses the planetary gear reduction mechanism described above. As shown in FIG. 2, the center case 5 has a large diameter cylindrical portion 51, an end wall portion 52 extending radially inward from a left end of the large diameter cylindrical portion 51, and an axial end extending from an inner end of the end wall portion 52. The small diameter cylindrical portion 53 is fitted with a bearing 4c for supporting a drive shaft, and the left end of the small diameter cylindrical portion 53 is engaged by a ser clip 19 via a stress washer 18. It has been stopped.

Next, the concavo-convex fitting portion 7 will be described with reference to FIG. The left end portion of the internal gear 44 slightly projects in the radial inward direction, and the inner peripheral surface of the left end portion having the smaller diameter is
As shown in FIG. 3, an uneven surface 70 is formed in which unevenness of about 1 mm is formed at an angular pitch of about 36 degrees. In addition,
The uneven surface 70 has an average radius of about 25 mm and an axial width of about 10 mm.

On the other hand, a projection 71 is axially projected from the end wall portion 52 of the center case 5 at a position where it is fitted to the uneven surface 70. The protrusions 71 have a short-axis columnar shape, and six protrusions 71 are arranged at equal intervals. The protrusion 71 has a radius of about 6 mm and an axial length of about 8 mm. The uneven surface 70 and the projection 71 described above form the uneven fitting portion 7 in the present embodiment.

Next, the operation of the above device will be described. When the magnet switch 3 is activated, the plunger 30 is attracted and the lever 66 swings clockwise, and the tip of the lever 66 advances the pinion 65 via the spline tube 60 and the one-way clutch 6. . Immediately before the pinion 65 collides with a ring gear (not shown), the contact of the magnet switch 3 is closed, a current flows through the starter motor 2, and the starter motor 2 is activated.

The rotating torque of the armature shaft 11 is
It is decelerated and transmitted to the internal combustion engine through the planetary gear 30, the drive shaft 4, the spline tube 60, the one-way clutch 6, the pinion 65, and the ring gear via the sun gear 19. At this time, the protrusion 71 is fitted in the concave portion of the uneven surface 70, so that the rotation of the internal gear 44 is blocked by the housing 1 through the center case 5.

Now, when a ring gear (not shown) is meshed with the pinion 65, a meshing impact as shown in FIG.
The reaction torque reaches the drive shaft 4, and the planetary gear 30 pivotally supported by the drive shaft 4 moves from the planetary gear 30 to the sun gear 1.
9 and the internal gear 44. Since the reaction torque transmitted to the internal gear 44 sets the size required for the projection 71 in the concave-convex fitting portion 7 to overcome the convex portion of the concave-convex surface 70 to be equal to or less than the allowable bending strength of the tooth, The null gear 44 rotates, and the rotation of the internal gear 44 cuts the impact below the allowable bending strength of the teeth (see FIG. 9). Further, frictional heat is generated in the uneven fitting portion 7, and impact energy is converted into heat.

Here, the uneven surface 70 is the internal gear 4
Since the inner teeth 45 are arranged at the right end of the left end of 4, the impact force (generated in the radial direction and the circumferential direction) at the previous stage where the protrusion 71 gets over the protrusion of the uneven surface 70 is generated from this resin. The cylindrical portion 44a of the internal gear 44 is favorably absorbed by twisting, distortion, and bending, and the repeated impact force reaching the inner teeth 45 during cranking is mitigated (see FIG. 9).

Therefore, the internal teeth 4 of the internal gear 44 are
The above-mentioned impact at the time of meshing transmitted from 5 to each part of the planetary gear 30 and the planetary gear speed reduction mechanism is cut, and the repeated impact at the time of cranking is alleviated, resulting in defects (tooth breakage, uneven wear of tooth surfaces and bearing surfaces, Generation of abnormal noise, decrease in transmission efficiency, etc.)
Is significantly reduced. Further, the heat generated in the uneven fitting portion 7 does not act on the internal teeth 45 of the internal gear 44,
It is possible to reduce the temperature on the inner tooth surface of the internal gear 44 and avoid the strength deterioration and the lubricating oil deterioration of the inner teeth 45.

As a result, although two types of shock absorption can be realized with a simple structure, smooth operation of the planetary gear speed reduction mechanism can be realized. Hereinafter, a method of manufacturing the internal gear 44 and the center case 5 will be described. The internal gear 44 is formed by molding nylon capable of being strengthened by the impact relaxation, and the center case 5 is formed by deep drawing a carbon steel sheet. It is formed by a multi-step pressing process, and the protrusion 71 is formed somewhere in these processes. Of course, instead of the protrusion 71, the uneven surface 7
It is also possible to have an uneven surface that fits with zero.

Therefore, by configuring as described above, FIG.
As shown in Fig. 5, the impact σ _b during meshing is cut to less than the allowable bending strength of the tooth, and the repeated impact σ _c during cranking
As shown in FIG. 6, module M0.9 and reduction ratio 7.5 can be realized while the internal gear 44 has a diameter of 60 mm. As a result, the planetary gear reduction starter can be realized. In the
It was possible to reduce the size.

Further, with the above-described structure, the clutch 6 can be made smaller, the housing 1 can be made thinner and lighter, and the ring gear 14 can be prevented from being damaged and the wear can be reduced. (Embodiment 2) Another embodiment is shown in FIG. This example is
The uneven surface 70 is provided on the outer peripheral surface of the left end portion of the internal gear 44, and the protrusion 71 is provided on the inner peripheral surface of the center case 5, and the same effect as that of the first embodiment can be obtained.

(Embodiment 3) Another embodiment is shown in FIG. In this embodiment, the uneven surface 7 is formed on the left end surface of the internal gear 44.
0 is provided and the projection 71 is provided on the inner end surface of the center case 5, and the same effect as that of the first embodiment can be obtained.

Further, in this embodiment, the protrusion 71 is formed on the uneven surface 7.
The impact when riding over the convex portion of 0 results in thrust in the axial direction and torsional force in the circumferential direction, which is preferable because it does not promote eccentricity of each part of the planetary gear reduction mechanism. (Embodiment 4) Next, the operation of another embodiment shown in FIG. 10 will be described below.

First, when the switch 103 is turned on, the holding coil 101 and the suction coil 102 are energized, the plunger 30 is attracted, the lever 66 swings clockwise, and the tip of the lever 66 is the spline tube 60 in one direction. The pinion 65 is moved forward through the sex clutch 6 and brought into contact with the ring gear 14. At this point, the fixed contact 10
5 is not closed by the movable contact 106.

Next, the electric current flowing through the suction coil 102 is supplied to the armature 108, and the armature 108 makes an auxiliary rotation (low speed rotation). By the auxiliary rotation of the armature 108, the pinion 65 rotates together with the drive shaft 4 via the planetary gear speed reducer, and the pinion 65 meshes with the ring gear 14. Pinion 65 is stopper 10
Plunger 10
7 has almost completed the suction, and the fixed contact 105 is closed by the movable contact 106 at the rear end, so that the current is directly supplied from the battery 104 to the armature 108, and the starter operates.

Therefore, since the armature 108 rotates at the position where the pinion 65 contacts the ring gear 14, the pinion 65 is forcibly engaged with the ring gear 14,
Compared to the drive spring system, the starter operates when the pinion 65 is fully meshed with the ring gear 14.
The armature assisted rotation type (first shock absorbing device) described above is used when the starter is operating.
Since the urging force of the rotation of 3 is small, the impact at the time of meshing between the pinion 65 and the ring gear 14 is reduced (eased) as shown in FIG.

Further, as in the first embodiment, twisting and distortion of the cylindrical portion 44a of the internal gear 44 made of resin,
The flexure is absorbed well, and the repeated impact force reaching the inner teeth 45 during cranking is mitigated (see FIG. 11). In each of the above-described embodiments, the concave-convex fitting portion 7 is provided on the internal gear 44 and the center case 5, but the concave-convex fitting portion includes a member fixed to the internal gear 44 and a member fixed to the center case 5. It is also possible to configure 7.

In each of the above-described embodiments, the uneven surface 70 is used as an interface.
Although the protrusion 71 is provided on the null gear 44 on the center case 5, the combination may be reversed. Needless to say, the gear specification may be DP display instead of module display. In this case, it exceeds DP 25.4. The point is that the number of modules is 1 or less.

As a shock absorbing device, Japanese Patent Publication No. 2-
A sliding shock absorbing device using a friction plate disclosed in Japanese Patent No. 33872, a shock absorbing device caused by strain of an elastic body disposed between an internal gear and a starter frame disclosed in Japanese Patent Laid-Open No. 59-23065, and the like. Various shock absorbing devices can be adopted, and the method is not limited.

[Brief description of drawings]

FIG. 1 is a partial sectional front view showing an embodiment of a starter with a planetary gear speed reduction mechanism according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a cross-sectional view taken along the arrow X in FIG.

FIG. 4 is a partial cross-sectional view showing another embodiment.

FIG. 5 is a partial cross-sectional view showing another embodiment.

FIG. 6 is a characteristic diagram showing a module with respect to a reduction ratio.

FIG. 7 is a schematic diagram showing a configuration of each gear.

FIG. 8 is a characteristic diagram showing an impact value P with respect to time T.

9 is a characteristic diagram showing an impact value P with respect to time T. FIG.

FIG. 10 is a partial cross-sectional front view showing another embodiment.

FIG. 11 is a characteristic diagram showing an impact value P with respect to time T.

[Explanation of symbols]

 2 Starter motor 4 Drive shaft 7 Concavo-convex fitting part 11 Armature shaft 14 Ring gear 19 Sun gear 30 Planetary gear 44 Internal gear 45 Internal gear of internal gear 65 Pinion 70 Concavo-convex surface of concavo-convex part 71 Concavo-convex Protrusion of fitting part.

Claims (3)

[Claims] 1. A starter motor having an armature core around which an armature coil is wound, an armature shaft rotatably holding the armature core, a drive shaft having a pinion that meshes with an engine ring gear, and the drive shaft. Generated when the pinion meshes with the ring gear, and is mounted between the armature shaft of the starter motor and a one-step planetary gear speed reducer for decelerating the rotation of the armature shaft and transmitting it to the drive shaft. And a second shock absorber that suppresses a shock during cranking, and the module (M) of the gears of the planetary gear speed reducer is 1 or less, and A planetary gear reduction type starter characterized by a reduction ratio exceeding 6. 2. The planetary gear reduction type starter according to claim 1, wherein the first shock absorber suppresses rotation of the starter motor when the pinion meshes with a ring gear of the engine, A planetary gear speed reduction type starter, characterized in that a meshing impact between the pinion and the ring gear is reduced. 3. The planetary gear speed reducer starter according to claim 1, wherein the second shock absorbing device rotates the internal gear of the planetary gear speed reducer against repetitive stress during cranking. A planetary gear reduction starter characterized by absorbing by flexure.