JP2004140931A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor capable of improving the durability and strength of a worm and a counter gear. <P>SOLUTION: This motor 10 comprises a pair of worms 15, 15' formed by making twisting directions of screws in reverse directions to each other near one end of a motor shaft 14; a pair of the counter gears 30, 30 which include a large-diameter gear 31 and a small-diameter gear 35, face each other with the motor shaft 14 sandwiched, and engaged with each large-diameter gear 31 in each worm; and an output gear 40 engaged with the small-diameter gear 35 of each counter gear. The large-diameter gear 31 of each counter gear are formed out of synthetic resin, the small-diameter gear 35 is formed out of metal, teeth 32 engaged with each worm are formed on the outer periphery of the large-diameter gear 31, an internal spline 33 is formed on the outer periphery of the large-diameter gear 31, and teeth 36 engaged with the output gear 40 and an external spline 37 engaged with the internal spline 33 of the large-diameter gear are integrally formed in the axial direction on the outer periphery of the small-diameter gear 35. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a motor such as a wiper motor of an automobile or a drive motor for seat slide.
[0002]
[Prior art]
FIGS. 7 and 8 show this type of motor (for example, see Patent Document 1).
[0003]
As shown in FIGS. 7 and 8, the wiper motor 1 has a motor shaft 4 rotatably supported by a motor case 2 and a gear case 3, and a screw torsion direction near one end of the motor shaft 4 in the gear case 3. A pair of large-diameter gears 7a, 8a and a pair of large-diameter gears 7a, 8a opposed to each other with the motor shaft 4 interposed therebetween and meshed with the pair of worms 5, 6, respectively. A pair of counter gears 7 and 8 having small diameter gears 7b and 8b serving as a core and integrally rotating, and an output gear 9 meshed with the small diameter gears 7b and 8b of the pair of counter gears 7 and 8 are provided. .
[0004]
As shown in FIG. 8, an output shaft 9A is fixed to the center of the output gear 9, and the output shaft 9A is connected to a part projecting outward from the gear case 3 to a wiper link (not shown). Has become.
[0005]
In the wiper motor 1, the pair of counter gears 7, 8 mesh with the pair of worms 5, 6 in which the screw twist directions are opposite to each other, and rotate. The direction of the thrust load generated by the combination is canceled by being opposite to the direction of the thrust load generated by the combination of the other worm 6 and the counter gear 8, so that a high-precision and strong thrust bearing is not required, and the motor shaft 4 is not required. , And the rotation of the wiper motor 1 becomes smooth.
[0006]
[Patent Document 1]
JP-A-55-112449 (page 1, FIG. 1 and FIG. 2)
[0007]
[Patent Document 2]
JP-A-9-175334 (page 5, FIG. 1 and FIG. 2)
[0008]
[Problems to be solved by the invention]
However, in the conventional wiper motor 1, since the motor shaft 4 (the respective worms 5, 6) and the respective counter gears 7, 8 are both made of metal, the respective worms 5, 6 are worn by the respective counter gears 7, 8. The durability was bad. In order to cope with this, in recent years, wear of the worm has been prevented by using a counter gear formed of a synthetic resin, but the strength was lower than that of a metal gear.
[0009]
Then, this invention is made in order to solve the above-mentioned subject, and an object of this invention is to provide the motor which can improve the durability and intensity | strength of a worm and a counter gear.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 is a motor shaft rotatably supported, and a pair of worms formed near the one end of the motor shaft with screw twist directions opposite to each other, and opposed to each other with the motor shaft interposed therebetween. A pair of counter gears each having a large-diameter gear meshing with the pair of worms, a small-diameter gear concentric with the large-diameter gear and rotating integrally therewith, and an output meshed with each small-diameter gear of the pair of counter gears. In the motor provided with a gear, the large-diameter gear of each counter gear is formed of a synthetic resin, and the small-diameter gear is formed of a metal, and meshes with the worm on the outer periphery of the synthetic resin large-diameter gear. While forming the tooth portion, the inner spline is formed on the inner periphery of the large-diameter gear, while the tooth portion meshing with the output gear and the inner spline of the large-diameter gear are formed on the outer periphery of each small-diameter gear made of metal. An outer spline to be combined is formed in a concentric step shape in the axial direction, and the inner spline of the large-diameter gear and the outer spline of the small-diameter gear are engaged with each other so that both gears are fixed in the rotational direction and integrally rotated. It is characterized by having done.
[0011]
In this motor, the large-diameter gear of the counter gear meshing with the worm is formed of synthetic resin, and the small-diameter gear of the counter gear meshing with the output gear is separately formed of metal. Since the inner spline and the outer spline of the metal small-diameter gear mesh with each other to rotate the two gears integrally, the durability and strength of the worm and the counter gear are improved.
[0012]
According to a second aspect of the present invention, in the motor according to the first aspect, the synthetic resin large-diameter gear has a flange portion integrally protruding toward a center in a radial direction at an inner peripheral edge of both axial end surfaces. The outer spline of the metal small-diameter gear is gripped between the pair of flanges to fix the small-diameter gear in the axial direction of the large-diameter gear, and the shaft of the outer spline of the metal small-diameter gear. The center of the direction and the center of the worm are arranged at substantially the same position.
[0013]
In this motor, the rotational force applied to the metal small-diameter gear from the worm via the synthetic resin large-diameter gear is received in good balance at substantially the center of the outer spline of the small-diameter gear. This makes it less susceptible to the influence of the reaction force between the worm and the counter gear other than the rotational force, and improves the strength and durability of the meshing portion between the inner spline of the large-diameter gear and the outer spline of the small-diameter gear that constitute the counter gear. Thus, destruction of the worm and the counter gear due to external force is reliably prevented.
[0014]
Here, the large diameter gear made of synthetic resin and the small diameter gear made of metal can be fixed by insert molding when the large diameter gear is formed by molding.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a plan view showing a motor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the motor, FIG. 3 is a plan view showing a state where a gear case cover and the like of the motor are removed, and FIG. FIG. 5 is an exploded perspective view of a counter gear used in the motor, and FIG. 6 is a perspective view of the counter gear.
[0017]
As shown in FIGS. 1 to 3, the motor 10 fastens a substantially cylindrical yoke (motor case) 11 having an open end to a flange portion 11 b around an open end 11 a of the yoke 11 via a screw 20 a. And a fixed gear case 21.
[0018]
As shown in FIG. 2, a pair of magnets 12, 12 are fixed to the inner peripheral surface 11c of the yoke 11 via an adhesive or the like. An armature shaft (motor shaft) is formed by the radial bearing 13a fitted to the bottomed cylindrical portion 11d at the other end of the yoke 11, and the radial bearings 13b and 13c fitted near both ends of the shaft hole 22 of the gear case 21. 14 is rotatably supported.
[0019]
The armature shaft 14 has a pair of worms 15 and 15 'formed near the one end, in which the screw twist directions are opposite to each other. An armature 16 is attached to the armature shaft 14 at a position facing the pair of magnets 12. The armature 16 includes an armature core 16a fixed to the armature shaft 14 and having a coil winding portion 16b having a predetermined number of slots, and an armature coil 16c wound around the coil winding portion 16b of the armature core 16a. Have been.
[0020]
Further, a commutator 17 is fixed at a position facing the boundary between the yoke 11 and the gear case 21 of the armature shaft 14. The commutator 17 has the same number of commutator pieces 17a as the coil winding portions 16b of the armature core 16a, and each commutator piece 17a is electrically connected to the armature coil 16c.
[0021]
Further, the open end of the shaft hole 22 of the gear case 21 is a large-diameter hole 22a, and a pair of brushes 19, 19 is located at a position facing the commutator 17 in the large-diameter hole 22a via a holder 18. Is attached so as to contact the commutator piece 17a. Each brush 19 is electrically connected to a motor control circuit (not shown). When the switch of the motor control circuit is switched from off to on, a current flows through the armature 16 and the like, and the armature shaft 14 rotates.
[0022]
As shown in FIGS. 2 to 4, a shaft hole 22 is formed substantially at the center of the gear case 21, and a concave reduction mechanism housing portion 23 is formed in communication with the shaft hole 22. Cylindrical bosses (thrust bearings for counter gears) 24 and 24 ′ are integrally formed at predetermined positions on the bottom wall of the reduction mechanism housing portion 23 between the pair of worms 15 and 15 ′. In the center of each cylindrical boss 24, 24 ', a circular recess 25, 25' is formed. A lower portion 26a of a pin-shaped support shaft 26 made of metal is fitted into each of the recesses 25 and 25 'by press-fitting or the like, and a counter gear 30 is rotatably supported on each support shaft 26. A circular hole 27a is formed at a position on the bottom wall of the speed reduction mechanism accommodating portion 23 near the right end of the worm 15 in FIG. 3, and a substantially annular rib 27b is integrally formed around the circular hole 27a. I have. The lower end 41a of the cylindrical portion 41 of the output gear 40 is rotatably supported in the substantially annular rib 27b via a radial bearing 28a.
[0023]
Further, as shown in FIGS. 1 and 4, one end opening of the speed reduction mechanism housing portion 23 of the gear case 21 is covered with a gear case cover 29 made of metal and substantially triangular and fastened to the gear case 21 with screws 20b. . Circular recesses 29a, 29a are formed in the gear case cover 29 at positions facing the recesses 25, 25 'of the reduction mechanism housing portion 23. The upper portion 26b of the support shaft 26 is fitted into each of the concave portions 29a by press fitting or the like. A circular hole 29b is formed in the gear case cover 29 at a position facing the circular hole 27a of the speed reduction mechanism accommodating portion 23. The upper end 41b of the cylindrical portion 41 of the output gear 40 is rotatably supported in the circular hole 29b via a thrust / radial bearing 28b. The pair of worms 15, 15 ′, the pair of counter gears 30, 30 and the output gear 40 are housed in a speed reduction mechanism housing 23 of the gear case 22 to form a speed reduction mechanism.
[0024]
As shown in FIGS. 2 and 4 to 6, each counter gear 30 includes a large-diameter gear 31 made of synthetic resin and a small-diameter gear 35 made of metal. The large-diameter gear 31 made of synthetic resin has teeth 32 that mesh with the worms 15 and 15 ′ on the outer periphery, and the inner spline 33 is formed on the inner periphery of the large-diameter gear 31. . A small-diameter tooth portion 36 meshing with a tooth portion 42 formed integrally with the cylindrical portion 41 of the output gear 40 and a large-diameter meshing with the inner spline 33 of the large-diameter gear 31 are provided on the outer periphery of the metal small-diameter gear 35. And the outer spline 37 are integrally formed in a concentric step shape in the axial direction.
[0025]
Further, as shown in FIGS. 4 and 6, a pair of flanges 34a and 34b are respectively formed on the inner peripheral edges of both ends in the axial direction of the large diameter gear 31 made of synthetic resin in an annular shape toward the center in the radial direction. The small-diameter gear 35 is fixed in the axial direction of the large-diameter gear 31 by gripping the outer spline 37 of the small-diameter metal gear 35 between the pair of flanges 34a and 34b.
[0026]
The support shaft 26 is inserted into a through hole 38 formed at the center of the small-diameter gear 35. The small-diameter gear 35 and the large-diameter gear 31 meshed with the outer spline 37 of the small-diameter gear 35 are inserted into the support shaft 26. Are designed to rotate together. As shown in FIG. 4, the lower surface of the tooth portion 32 of the large-diameter gear 31 made of synthetic resin is slidable on the cylindrical bosses 24 and 24 ′ of the reduction mechanism housing 23. Further, the center O1 in the axial direction of the inner spline 33 of the large-diameter gear 31 made of synthetic resin and the outer spline 37 of the small-diameter gear 35 made of metal and the center O2 of each of the worms 15 and 15 'are located at substantially the same horizontal position. It is arranged. That is, the worms 15 and 15 'are arranged so as to have a uniform thickness with respect to the center of meshing between the teeth 32 of the large-diameter gear 31 and the worms.
[0027]
As shown in FIG. 4, an output shaft 43 is fixed in the cylindrical portion 41 of the output gear 40, and a portion of the output shaft 43 that protrudes outward (downward in FIG. 4) from the gear case 21 is, for example, An automobile wiper link (not shown) is connected.
[0028]
According to the motor 10 of the embodiment described above, the pair of counter gears 30, 30 mesh with the pair of worms 15, 15 'in which the torsional directions of the screws near one end of the armature shaft 14 are opposite to each other, and rotate. Therefore, the direction of the thrust load generated by the combination of one worm 15 and the counter gear 30 is opposite to the direction of the thrust load generated by the combination of the other worm 15 ′ and the counter gear 30, and is canceled. This eliminates the need for a high-precision and strong thrust bearing that rotatably supports each counter gear 30, and eliminates backlash of the armature shaft 14 of the motor 10, so that the armature 16 rotates smoothly.
[0029]
The large-diameter gear 31 of each counter gear 30 meshing with the pair of worms 15 and 15 ′ near one end of the armature shaft 14 is formed of synthetic resin, and each counter gear 30 meshing with the tooth portion 42 of the output gear 40. Are separately formed of metal, and the inner spline 33 of the synthetic resin large-diameter gear 31 and the outer spline 37 of the metal small-diameter gear 35 are meshed to rotate the two gears 31 and 35 integrally. As a result, the durability and strength of the worms 15, 15 'and the counter gear 30 can be improved.
[0030]
Further, the outer spline 37 of the metal small-diameter gear 35 is gripped between a pair of flanges 34a and 34b formed integrally on the inner peripheral edges of both ends in the axial direction of the synthetic resin large-diameter gear 31 so as to grip the small-diameter gear. 35 are fixed in the axial direction of the large-diameter gear 31, and the axial center O1 of the inner spline 33 of the synthetic resin large-diameter gear 31 and the outer spline 37 of the metal small-diameter gear 35 and the worms 15, 15 '. Of the small-diameter gear 35 from the worms 15 and 15 ′ via the large-diameter gear 31 made of synthetic resin to the small-diameter gear 35 made of metal. It can be received in a good balance at substantially the center of the outer spline 37. As a result, the counter gear 30 is hardly affected by the meshing reaction force between the worms 15, 15 'and the counter gears 30, 30 other than the rotational force, and the inner spline 33 of the large-diameter gear 31 and the small-diameter gear 35 constituting the counter gear 30 are formed. The strength and durability of the meshing portion of the outer spline 37 can be further improved, and the worms 15, 15 'and the counter gear 30 can be reliably prevented from being broken by an external force.
[0031]
Here, the relative fixing of the large-diameter gear 31 and the small-diameter gear 35 in the rotational direction and the axial direction is performed by insert molding when the synthetic resin large-diameter gear 31 is formed by molding.
[0032]
According to the above-described embodiment, the case where the motor is a wiper motor of an automobile has been described. However, it is needless to say that the embodiment can be applied to other motors such as a seat slide driving motor.
[0033]
【The invention's effect】
As described above, according to the invention of claim 1, the large-diameter gear of the counter gear meshing with the worm of the motor shaft is formed of synthetic resin, and the small-diameter gear of the counter gear meshing with the output gear is formed of metal. Since the inner spline of the large diameter gear made of synthetic resin and the outer spline of the small diameter gear made of metal are engaged with each other to rotate the two gears integrally, the durability and strength of the worm and the counter gear are reduced. Can be improved.
[0034]
According to the invention of claim 2, the outer spline of the metal small-diameter gear is gripped between a pair of flanges integrally formed on the inner peripheral edges of both ends in the axial direction of the synthetic resin large-diameter gear to reduce the diameter. The gear was fixed in the axial direction of the large-diameter gear, and the center of the outer spline of this small-diameter metal gear was axially aligned with the center of the worm. The rotational force applied to the metal small-diameter gear via the large-diameter gear can be received in good balance at substantially the center of the outer spline of the small-diameter gear. This makes it less susceptible to the influence of the reaction force between the worm and the counter gear other than the rotational force. The worm and the counter gear can be reliably prevented from being broken by an external force.
[Brief description of the drawings]
FIG. 1 is a plan view showing a motor according to an embodiment of the present invention.
FIG. 2 is a sectional view of the motor.
FIG. 3 is a plan view showing a state where a gear case cover and the like of the motor are removed.
FIG. 4 is a sectional view taken along line AA in FIG.
FIG. 5 is an exploded perspective view of a counter gear used in the motor.
FIG. 6 is a perspective view of the counter gear.
FIG. 7 is a partial sectional view of a conventional motor.
FIG. 8 is a sectional view taken along line BB in FIG. 7;
[Explanation of symbols]
10 Motor 14 Armature axis (motor axis)
15, 15 'Worm 30, 30 A pair of counter gears 31 A large diameter gear 32 A tooth portion 33 An inner spline 34a, 34b A pair of flange portions 35 A small diameter gear 36 A tooth portion 37 An outer spline 40 Output gear O1 Axial direction of an outer spline of the small diameter gear Center O2 Warm center

Claims (3)

A rotatably supported motor shaft, a pair of worms formed in the vicinity of one end of the motor shaft with the screw torsion directions opposite to each other, and opposed to each other with the motor shaft interposed therebetween. A motor including a large-diameter gear that meshes, a pair of counter gears having a small-diameter gear that is concentric with the large-diameter gear and rotates integrally, and an output gear that meshes with each small-diameter gear of the pair of counter gears. ,
The large-diameter gear of each of the counter gears is formed of synthetic resin, the small-diameter gear is formed of metal, and teeth of the large-diameter gear made of synthetic resin mesh with the worm. An inner spline is formed on the inner periphery of the large-diameter gear, while a tooth portion meshing with the output gear and an outer spline meshing with the inner spline of the large-diameter gear are formed on the outer periphery of each small-diameter gear made of metal in the axial direction. A motor formed in a concentric step shape, wherein an inner spline of the large-diameter gear and an outer spline of the small-diameter gear are engaged to fix both gears in a rotational direction and rotate integrally. The motor according to claim 1,
On the inner peripheral edges of both end surfaces in the axial direction of the synthetic resin large-diameter gear, a flange portion integrally protruding toward the center in the radial direction is formed, and between the pair of flange portions, the outside of the metal small-diameter gear is formed. The spline is gripped to fix the small-diameter gear in the axial direction of the large-diameter gear, and the center of the outer spline of the small-diameter metal gear in the axial direction and the center of the worm are arranged at substantially the same position. A motor characterized in that: The motor according to claim 2,
The motor, wherein the large-diameter gear made of synthetic resin and the small-diameter gear made of metal are fixed by insert molding when the large-diameter gear is formed by molding.

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