JPH0138185B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an internal combustion engine starter used to start an internal combustion engine, and is an electric motor starter suitable for use in automobiles, etc., and is small and lightweight. This invention relates to a starter for an internal combustion engine that incorporates a planetary gear mechanism.

[Background of the invention]

BACKGROUND ART Conventionally, as a starter for an internal combustion engine, a type directly connected to an electric motor as shown in FIG. 1 has often been used. To explain the outline of this operation, when the driver turns on the key switch, the solenoid coil 1 is energized, which causes the shift lever 2 to start moving, and before the shift lever 2 completes its movement, the electric motor is energized and the armature 3 of the electric motor is turned on. starts rotating.
At this time, the shift lever 2 is connected to the armature shaft 3.
One-way clutch 4 and pinion 5a engaged with helical spline 3b integrally formed in a
Since we are moving it in the axial direction, to the right in the figure,
The pinion 5a engages with a ring gear (also not shown) integrally attached to the crankshaft of the internal combustion engine (not shown) to start the internal combustion engine. There has been a strong demand for starters for such internal combustion engines to be smaller and lighter due to the recent demands for energy saving and noise reduction in automobiles, but in the case of starters that are directly connected to the electric motor, there are problems such as magnetic saturation in the iron core. Due to this phenomenon, there was a limit to miniaturization because the required output torque could no longer be obtained. In view of this drawback, a method has been proposed in which a planetary gear mechanism is integrated as in Utility Model Application Publication No. 58-132171, but as is well known, in a planetary gear mechanism, multiple planetary gears are In order to transmit power, if the power is not evenly distributed between the planetary gears, the reducer will be damaged due to excessive load.
Alternatively, there is a problem that vibration noise increases. Incidentally, an important feature of starters for internal combustion engines is that both the driving side, that is, the electric motor, and the driven side, that is, the internal combustion engine, have impulsive torque characteristics. That is, a planetary gear reduction mechanism used in a starter for an internal combustion engine must not only distribute power equally but also withstand impact loads. Considering this point of view, among the conventional power equalization mechanisms, the so-called sun gear floating type equalization mechanism, which restrains the sun gear only in the rotational direction with respect to the shaft, has an impact load on the internal combustion engine side that is at least as strong as the planetary gear pin. This is also undesirable because it can be transmitted to the meshing portion of the planetary gear and the internal gear. Similarly, the method of floating the carrier is undesirable because the impact torque generated by the electric motor can be transmitted to each meshing part of the sun gear, planetary gear, and internal gear, and there is also a risk of fretting occurring at the joint between the carrier and the output shaft. There is also gender. In other words, in order to satisfy both power distribution and shock load mitigation, the internal gear, which is a reaction force support member in a differential device in a broad sense, should be supported floatingly so that it can move in the radial direction, and should also be able to be elastically deformed. It turns out that it should. Said Utsukai Showa 58-
In Publication No. 132171, the ring gear (internal gear) has a structure that can absorb the impact load by moving in the axial direction, but the amount of radial movement required for equal power distribution is the maximum. It is no exaggeration to say that the helical spline cannot move substantially in the radial direction considering the accuracy of the helical spline, which is at least up to the minimum value of the backlash in the direction normal to the tooth surface of the helical spline. In addition, in this method, the ring gear (internal gear) member has teeth on both the outer and inner peripheries to support the load, so the rim thickness is reduced to prevent cracks in the rim due to stress concentration at the root of the teeth. The rim must be made thicker, significantly reducing the flexibility of the rim, and in this respect also reducing power distribution.

[Purpose of the invention]

In view of the above points, an object of the present invention is to provide a starter for an internal combustion engine that is small and lightweight, has no fear of breakage, and has low vibration and noise.

[Summary of the invention]

The present invention is characterized by an internal gear support system that can increase the floating range of the internal gear and improve the flexibility of the internal gear rim. The inner end face of the reducer casing facing the end face is provided with protrusions of the same number or less than the grooves, and by engaging these grooves and protrusions, the reaction force received by the internal gear is transferred to the reducer casing. At the same time, a radial clearance is provided between the outer periphery of the internal gear and the inner periphery of the reducer casing, which is at least larger than the amount of elastic deformation occurring in the internal gear and the protrusion.

With the above configuration, since the projection is a cantilever beam, the internal gear engaged with the free end of this projection is displaced within the range of the amount of elastic deformation of the projection. Therefore, when an impact load is applied, the protrusion deforms, the internal gear is displaced in the radial direction, and the impact is absorbed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a longitudinal cross-sectional view showing one embodiment of the present invention, and FIG. 3 is an enlarged view of the main parts thereof. In the figure, reference numeral 6 denotes a motor housing that rotatably supports one shaft end of the armature 8 and fixes the stator 7. One end of the motor housing 6 is provided with a fitting portion 6a. constitutes the reducer casing. Both the bracket 9 and the cover 10 are fitted and fixed to the main bracket 13 with bolts. The stator 7 is made up of a plurality of magnetized permanent magnets and constitutes the field of the motor, but since this is similar to a conventionally known DC motor, a detailed explanation will be omitted. Armachia 8
The core 8b is press-fitted into the approximate center of the armature shaft 8a, and the winding 8 is wound around the core 8b.
c, a commutator 8d for supplying power to the winding 8c from the outside by a brush (not shown); one end of the armature shaft 8a is connected to the motor housing 6;
It is rotatably inserted into a bearing 6b that is integrally attached therein, and the other end is integrally formed with a bearing part 8e rotatably supported by a bracket 9 and a sun gear 8f which is an input to a planetary gear reducer. has been done.
Motor housing 6, bracket 9 and cover 1
The starter is attached to a flywheel housing (not shown) of an internal combustion engine, and is also attached by bolts to a main bracket 13 that holds a solenoid coil 11 for operating the starter, a shift lever 12, etc. The cover 10 has a bearing part 10a in the center that rotatably supports the starter output shaft 14, in which a carrier 14a of a planetary gear reducer is integrally formed. Extruded portions 10b are formed at six locations. This extrusion part 10
Six internal gear fixing pins 10c are fixed under pressure to b, and the tip of each fixing pin 10c protrudes from the surface of the cover 10 facing the internal gear 15. An internal gear 15 is provided on the protrusion of the fixing pin 10c.
A groove 15a provided on the end face of the internal gear 15 is engaged with the internal gear 15, thereby restricting movement of the internal gear 15 beyond a certain limit in both the rotational direction and the radial direction. The outer circumferential side of the internal gear 15 is covered with a bracket 9 whose inner circumference is larger than the outer circumference 15b of the internal gear 15, and between the internal gear 15 and the bracket 9,
A radial clearance h greater than the amount of elastic deformation occurring in the internal gear 15 and the protrusion is formed. The starter output shaft 14, which is rotatably supported by the bearing part 10a of the cover 10 and the bearing part 13a provided on the main bracket, has a carrier 14a integrally formed at one end, and a helical spline approximately at the center. 14b is formed. carrier 14a
Three planetary gear support pins 14c are driven and fixed at equal angular intervals concentrically with the starter output shaft 14, and each planetary gear support pin 14c has a planetary gear 17 with a bearing 16 inserted into its inner periphery. The planetary gear 17 is rotatably supported and meshes with the sun gear 8f and the internal gear 15, respectively.
f, planetary gear 17, internal gear 15 and carrier 14
A so-called planetary type planetary gear reducer is constituted by a. The helical spline 14b formed approximately at the center of the starter output shaft 14 includes
A helical spline 18a provided on the inner periphery of one end of the outer 18, which is moved in the axial direction of the starter output shaft 14 by the shift lever 12, is engaged, and the helical spline 18a allows the outer 18 to be moved in the axial direction of the starter output shaft 14. The outer 18 is coupled so that relative rotation beyond a certain limit is impossible. A cam 18b is formed on the inner periphery of the other end of the outer 18, and a roller 19 inserted into this cam 18b
A one-way clutch is formed by the inner 20, which has a pinion 20a at one end that meshes with a ring gear (not shown) provided in the internal combustion engine.

Next, the operation of the starter of the present invention configured as described above will be explained. The detailed operations of the relays and the like from when the driver turns on the key switch until the pinion 20a engages with the ring gear are not particularly different from those of conventional starters for internal combustion engines, and will therefore be omitted. When the driver turns on the key switch, the solenoid coil 11 is energized and the shift lever 12 starts to move.When the shift lever 12 has moved to a certain position, the winding 8c of the armature 8 is energized, and the armature 8 is turned on. Then, the sun gear 8f starts rotating rapidly. The rotational force applied to the sun gear 8f is first transmitted to the internal gear 15 via the tooth surface of the planetary gear 17. Here, the internal gear 15 is the internal gear fixing pin 10c.
Since the internal gear 15 is fixed to the reducer casing by the internal gear fixing pin 10c, the excessive impact torque generated by the motor is absorbed by the elastic deformation of the internal gear fixing pin 10c and the rim portion of the internal gear 15. Next, after the amount of elastic deformation of the internal gear 15 and the internal gear fixing pin 10c reaches the maximum, the carrier 1 is moved through the planetary gear support pin 14c.
4a and the output shaft 14 start rotating, and this rotation is transmitted to the pinion 20a via the outer 18, the roller 19 and the inner 20 via the helical splines 14b and 18b, and starts the internal combustion engine. At this time, excessive torque may be applied to the output shaft 14 from the internal combustion engine due to poor starting or irregular ignition, or the one-way clutch may not disengage properly, causing the output shaft 14 to be accelerated. Since this is also a shocking phenomenon, since the internal gear 15 is elastically supported, these impact loads are absorbed by the internal gear supporting portion, and at least the meshing portions of the sun gear and the planetary gears receive the impact load. can be prevented from acting. As described above, according to the present invention, it is possible to alleviate the impact load, which is a characteristic of starters for internal combustion engines. In addition, the internal gear floating system can increase power distribution. In other words, the internal gear can float by the amount of elastic deformation of the projection provided on the reducer casing as a cantilever beam, and the elastic deformation of the internal gear rim is also caused by stress concentration caused by the fact that the outer periphery is not constrained and the helical spline. Since there is no such problem, the amount of elastic deformation of the internal gear can be large, which has a great effect on equal distribution of power.
Furthermore, the assembly process of engaging the grooves and protrusions provided on the end face is much easier than the conventional process of engaging gear coupling springs, making it possible to significantly reduce costs during mass production. Become.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a vertical cross-sectional view of the main parts of the starter for an internal combustion engine seen from the same viewpoint as FIG. 2, and is a view focusing in particular on the support portion of the internal gear. In this figure, six extruded parts 10b are formed on the cover 10 concentrically with the bearing part 10a and toward the internal gear, while the internal gear 15 has a small mass and moment of inertia so that it can easily float. The groove 15a is made of a synthetic resin material and has a groove 15a that is slightly larger than the outer diameter of the extruded portion 10b. In this embodiment, the impact torque transmitted to the internal gear 15 is absorbed by the gap between the groove 15a and the extruded portion 10b and by the elastic deformation mainly in the groove 15a. This second embodiment has the same effect as the first.
This embodiment is similar to the embodiment described above, and the number of parts can be further reduced, the size and weight can be further reduced, and since the inertial resistance of the internal gear is small, the equal distribution of power can be further improved.

〔Effect of the invention〕

As described above, according to the present invention, the internal gear is floatingly supported by providing a locking groove in the end surface of at least one end of the internal gear and inserting the protrusion provided on the inner end surface of the reducer casing into the groove. In addition, since the outer periphery of the internal gear is not restricted by the inner periphery of the casing, it is possible to obtain a starter for an internal combustion engine that has high power distribution and can absorb impact loads. This makes it possible to reduce the size, weight, and cost of the starter for an internal combustion engine, resulting in extremely large economic effects such as energy savings during production and use.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a conventional starter for an internal combustion engine, FIG. 2 is a longitudinal sectional view showing an embodiment of the starter for an internal combustion engine of the present invention, and FIG. 3 is an enlarged view of the main part of FIG. FIG. 4 is a diagram showing another embodiment of the present invention. 6... Motor housing, 7... Starter, 8... Armature, 8f... Sun gear, 10b... Extrusion part,
10c...Internal gear fixed, 15...Internal gear, 15a...
Groove, 17... Planetary gear.

Claims (1)

[Scope of Claims] 1. In a starter for an internal combustion engine in which the rotation of an electric motor used to start the internal combustion engine is decelerated by a planetary gear reduction mechanism and transmitted to a ring gear provided in the internal combustion engine, the planetary gear A plurality of locking grooves are provided on at least one end surface of an internal gear that is a reaction force member of the mechanism, and a protrusion provided on an inner end surface of the reducer casing opposite to the grooves is inserted into the groove. The reaction force received by the internal gear is transmitted to the reducer casing, and there is a diameter between the outer periphery of the internal gear and the inner periphery of the reducer casing that is at least larger than the amount of elastic deformation occurring in the internal gear and the protrusion. A starter for an internal combustion engine characterized by providing a directional clearance. 2. An internal combustion engine according to claim 1, wherein the plurality of grooves provided on the end surface of the internal gear of the planetary gear mechanism are larger than the protrusions provided on the inner end surface of the reducer casing. Starter.