JP3884358B2 - Wiper motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wiper motor for rear window glass having a wiper shaft (pivot shaft) on which a wiper arm is mounted.
[0002]
[Prior art]
As this type of wiper motor, there is one shown in FIGS. 3 and 4 (see, for example, Patent Document 1).
[0003]
3 and 4, the wiper motor M is rotatably supported by a gear case 1 having an opening 1c at the end of a side wall 1b and a bottom wall 1a of the gear case 1, and the gear case 1 A wiper shaft 2 to which a not-shown wiper arm is mounted at a tip protruding outside the bottom wall 1a of the motor, a worm 3 of a motor shaft rotatably supported on a side wall 1b of the gear case 1, and a bottom wall 1a of the gear case 1 A helical gear 4 that is rotatably supported through a pin 4A and meshed with the worm 3, a rocking gear 5 in which a base portion 5a is rockably supported through a pin 5A, and a wiper shaft. 2 is fixed to the base portion 2a of the swinging gear 5, and is rotatably supported by the base portion 2a of the wiper shaft 2 and the output gear 6 meshed with the tooth portion 5b at the tip of the swinging gear 5. Teeth 5b and A pair of balanced plates 7, 7 for holding the meshing state between the power gear 6, and a cover 8 covering the opening portion 1c of the gear case 1, a gasket 9 disposed on the rear surface of the cover 8.
[0004]
As shown in FIG. 4, the tip 5B of the pin 5A passing through the circular hole 5c of the swinging gear 5 protrudes outward from the base 5a of the swinging gear 5, and the tip 5B of the protruding pin 5A. These end faces are in slidable contact with a gasket 9 disposed on the back surface of the cover 8.
[0005]
[Patent Document 1]
US Pat. No. 5,622,077 Specification
[Patent Document 2]
Japanese Patent Laid-Open No. 9-58416
[Problems to be solved by the invention]
However, in the conventional wiper motor M, when the user forcibly moves the wiper arm when the wiper is stopped at a fixed position and an excessive external force is input to the wiper shaft 2 in the direction indicated by the arrow Y in FIG. 4 floats in the direction of arrow A in FIG. 4 or bends in the direction of arrow B in FIG. 4, leading to bending deformation of the swing gear 5 and damage to the helical gear 4. In some cases, the wiper motor M could not be restarted.
[0008]
Therefore, the present invention has been made to solve the above-described problems, and reliably prevents deformation of the swinging gear and damage to the helical gear even if an excessive external force is input to the wiper shaft when the wiper is stopped at a fixed position. An object of the present invention is to provide a wiper motor that can perform the above-described operation.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, a case having an opening at the tip of the side wall, and a wiper arm attached to the tip of the case that is rotatably supported by the bottom wall of the case and that protrudes outside the bottom wall of the case Wiper shaft, a motor shaft worm rotatably supported on the side wall of the case, a helical gear rotatably supported on the bottom wall of the case and meshed with the worm, and a base portion of the helical gear Is fixed to the base of the wiper shaft, and the output gear meshed with the tooth portion at the tip of the swing gear, and the wiper shaft In a wiper motor comprising a balance plate that is rotatably supported by a base and that holds the meshing state of the tooth portion of the swing gear and the output gear, and a cover that covers the opening of the case. Spindle A tip end portion is projected outward from the base portion of the rocking gear, a disc-shaped cap is attached to the tip end portion of the projecting support shaft, and at least a part of the surface of the disc-shaped cap facing the cover is attached. While making the cover slidably contact with the cover, the radius of the disc-shaped cap is formed larger than the dimension from the center line of the support shaft to the outer periphery of the base of the swinging gear. The outer peripheral surface of the cap is brought close to the side wall of the case when the wiper is stopped at a fixed position.
[0010]
In this wiper motor, a tip end of a support shaft that swingably supports a base portion of a swinging gear on a helical gear protrudes outward from the base portion of the swinging gear, and a disc attached to the tip end portion of the protruding support shaft Since at least a part of the surface of the cap-like cap facing the cover is slidably brought into contact with the cover, it is possible to suppress the swinging gear from lifting up in the cover direction when the wiper is operated. In addition, since the outer peripheral surface of the disk-shaped cap formed with a large diameter in the state when the wiper fixed position is stopped is brought close to the side wall of the case, even if excessive external force is input to the wiper shaft when the wiper fixed position is stopped Since the outer peripheral surface of the cap abuts against the side wall of the case, the movement of the swing gear toward the side wall of the case is suppressed, and the helical gear is reliably prevented from being damaged.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a plan view showing a state when a wiper motor is stopped at a fixed position of a wiper motor according to an embodiment of the present invention, and FIG.
[0013]
As shown in FIG. 1, the wiper motor 10 is for a rear window glass. A motor case (case) 11 containing an armature and a magnet (not shown) and an opening 14c are covered by a cover 13 and will be described later. And a gear case (case) 14 in which a worm 16 and the like are accommodated. The gear case 14 and the motor case 11 are fastened and fixed by screws 12 at the open end 11 a of the motor case 11.
[0014]
As shown in FIGS. 1 and 2, the gear case 14 has a side wall 14b integrally projecting around a bottom wall 14a, and an opening 14c is formed at the tip of the side wall 14b. A long cylindrical portion 14d and a short cylindrical portion 14e are integrally formed at a predetermined position on the bottom wall 14a of the gear case 14. Further, a tip 16a of a worm 16 formed integrally with an armature shaft (motor shaft) 15 is rotatably supported via a thrust bearing 17 at a position facing the motor case 11 on the side wall 14b of the gear case 14. .
[0015]
As shown in FIG. 2, a wiper shaft 19 is rotatably supported in a long cylindrical portion 14d of the bottom wall 14a of the gear case 14 via a pair of bearings 18a and 18b. The distal end portion 19 a of the wiper shaft 19 protrudes outside the bottom wall 14 a of the gear case 14. A wiper arm 21 is detachably attached via a nut 20 to a tip portion 19a protruding outside. A serration is formed on the base portion 19b of the wiper shaft 19, and an output gear 22 is fixed to the base portion 19b on which the serration is formed. Further, the lower portion of the pin-shaped support shaft 23 is fitted into the short cylindrical portion 14 e of the bottom wall 14 a of the gear case 14. A helical gear (worm wheel) 24 meshed with the worm 16 is rotatably supported on the support shaft 23.
[0016]
A circular recess 24c is formed on the upper surface of the helical gear 24 at a position approximately in the middle between the center hole 24a and the outer peripheral tooth portion 24b. A lower portion 25a of a pin-shaped support shaft 25 is fitted into the recess 24c. A circular hole 26b of a base portion 26a of a metal swing gear 26 is passed through an upper portion 25b of the support shaft 25 so as to be swingable. Further, the distal end portion 25 c of the support shaft 25 protrudes outward from the round hole 26 b of the base portion 26 a of the swing gear 26, and the protruding end portion 25 c of the support shaft 25 is made of a synthetic resin and has a disk-like cap 27. A concave portion 27a at the center of the lower surface is fitted. Three circular convex portions (parts) 27c integrally formed on the upper surface (surface facing the cover 13) 27b of the cap 27 are slidably in contact with the back surface 13a of the cover 13. The radius of the disc-shaped cap 27 made of synthetic resin is formed larger than the dimension from the center line of the support shaft 25 to the outer periphery of the base portion 26a of the swing gear 26. The outer peripheral surface 27d of the belt 27 is close to the side wall 14b of the gear case 14 with a predetermined clearance when the wiper fixed position is stopped.
[0017]
As shown in FIGS. 1 and 2, the swing gear 26 is formed in a substantially fan shape, and a tooth portion 26 c that meshes with the output gear 22 is formed in the arc portion at the tip thereof. The meshing state of the tooth portion 26c of the swing gear 26 and the output gear 22 is determined by a pair of upper and lower balance plates 28 and 29 that are rotatably supported so as to hold the output gear 22 on the base portion 19b of the wiper shaft 19. It is supposed to be retained.
[0018]
The upper balance plate 28 is made of synthetic resin, and a circular mounting hole 28a is formed at the base end portion thereof, and a cylindrical convex portion 28b is integrally formed on the back surface of the tip end portion. . The mounting hole 28 a of the balance plate 28 is rotatably supported above the output gear 22 of the base portion 19 b of the wiper shaft 19, and the convex portion 28 b of the balance plate 28 is the upper surface of the distal end portion of the swing gear 26. It is rotatably supported by a circular recess 26d formed in the above. As a result, the meshing state of the tooth portion 26c of the swing gear 26 and the output gear 22 can be maintained, and the swing gear 26 is prevented from being lifted in the direction of the cover 13 (the direction of arrow A in FIG. 2). Can be done.
[0019]
Further, the lower balance plate 29 is made of iron plate, and a circular attachment hole 29a is formed at the base end portion, and a circular engagement hole (engagement portion) 29b is formed at the distal end portion. It is. The mounting hole 29 a of the balance plate 29 is rotatably supported below the output gear 22 of the base portion 19 b of the wiper shaft 19, and the engagement hole 29 b of the balance plate 29 is formed at the tip of the swing gear 26. It is rotatably supported by a columnar convex portion (locking portion) 26e formed at a position facing the concave portion 26d on the lower surface. Thereby, the meshing state of the tooth portion 26c of the swing gear 26 and the output gear 22 can be maintained.
[0020]
A wiper fixed position stop switch (not shown) is arranged at a position facing the helical gear 24 on the bottom wall 14a of the gear case 14, and when the wiper switch (not shown) is turned off, the helical gear 24, that is, the wiper shaft 19 is stopped for a predetermined time. It has a function of automatically stopping the wiper operation after being rotated to a position (position when the wiper fixed position is stopped as shown in FIG. 1).
[0021]
According to the wiper motor 10 of the embodiment described above, when the wiper switch is turned on, the helical gear 24 rotates via the worm 16. By the rotation of the helical gear 24, the distance from the rotation center of the center hole 24a of the helical gear 24 to the support shaft 25, the distance from the round hole 26b of the swing gear 26 to the convex portion 26e of the swing gear 26, the balance plate The output gear 22 is reciprocally rotated (that is, oscillated) by a link mechanism of a four-bar rotation chain formed by the distance from the engagement hole 29b of 29 to the mounting hole 29a that is the oscillation center of the balance plate 29. The wiper shaft 19 fixed to the gear 22 is reciprocally rotated so as to correspond to the wiper swinging range. As a result, the wiper arm 21 attached to the tip 19a of the wiper shaft 19 is swung within a predetermined range, and the rain water and the like on the rear window glass surface are wiped off by the wiper blade attached to the wiper arm 21.
[0022]
When the wiper switch is turned off, the wiper motor 10 stops at the position when the wiper fixed position stop shown in FIG. The swinging movement of the swinging gear 26 during the operation of the wiper motor 10 causes the swinging gear 26 to float up in the direction of the cover 13 (the direction of arrow A in FIG. 2), but the upper part of the balance plate 28 made of synthetic resin. In addition, the three protrusions 27c of the disc-shaped cap 27 made of synthetic resin abut against the back surface 13a of the cover 13 to suppress the lifting force of the swinging gear 26, thereby preventing the swinging gear 26 from being lifted. it can. Thereby, the wiper motor 10 can be operated smoothly.
[0023]
In particular, when the wiper fixed position is stopped, the outer peripheral surface 27d of the disc-shaped cap 27 having a large diameter made of synthetic resin is brought close to the side wall 14b of the gear case 14, so that the wiper is used when the wiper fixed position is stopped. Even if an operator forcibly moves the wiper arm 21 and an excessive external force is input to the wiper shaft 19, the outer peripheral surface 27 d of the cap 27 abuts against the side wall 14 b of the gear case 14, whereby the side wall 14 b of the gear case 14 of the oscillating gear 26. Movement in the direction (arrow B direction in FIGS. 1 and 2) can be suppressed. As a result, the movement of the support shaft 25 supporting the swing gear 26 in the direction of the cover 13 (the direction of arrow A in FIG. 2) can be reduced and reduced, and the deformation and breakage of the helical gear 24 made of synthetic resin can be reduced. It can be surely prevented.
[0024]
In addition, according to the said embodiment, although the wiper motor for rear window glass was demonstrated, it is needless to say that the said embodiment may be applied to the wiper motor for front window glass.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, the tip end portion of the support shaft, which is supported by the helical gear so that the base portion of the swinging gear is swingable, protrudes outward from the base portion of the swinging gear. Since at least a part of the face of the disc-shaped cap attached to the tip of the support shaft is slidably brought into contact with the cover, when the wiper is operated, the swing gear is moved toward the cover. You can suppress the lift. In addition, when the wiper is stopped at a fixed position , the outer peripheral surface of the disk-shaped cap having a radius larger than the dimension from the center line of the support shaft to the outer periphery of the base of the swing gear is used as the side wall of the case. Even if an excessive external force is input to the wiper shaft when the wiper is stopped at a fixed position, the outer peripheral surface of the cap hits the side wall of the case, so that the movement of the swing gear toward the side wall of the case is suppressed. Can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state when a wiper fixed position of a wiper motor according to an embodiment of the present invention is stopped.
FIG. 2 is a sectional view taken along line XX in FIG.
FIG. 3 is a plan view of a conventional wiper motor.
FIG. 4 is a sectional view of the conventional wiper motor.
[Explanation of symbols]
10 Wiper motor 13 Cover 14 Gear case (case)
14a Bottom wall 14b Side wall 14c Opening 15 Armature shaft (motor shaft)
16 Worm 19 Wiper shaft 19a Tip portion 19b Base portion 21 Wiper arm 22 Output gear 24 Helical gear 25 Support shaft 25c Tip portion 26 Swing gear 26a Base portion 26c Tooth portion 27 Cap 27b Upper surface (surface facing the cover)
27c Convex part (part)
27d Outer peripheral surface 28, 29 Balance plate

Claims (1)

A case having an opening at the front end of the side wall, a wiper shaft that is rotatably supported by the bottom wall of the case, and that has a wiper arm attached to a front end protruding outside the bottom wall of the case; A worm of the motor shaft that is rotatably supported on the side wall of the case, a helical gear that is rotatably supported on the bottom wall of the case and meshed with the worm, and a base portion of the helical gear that swings through the support shaft. An oscillating gear supported movably, an output gear fixed to the base of the wiper shaft, meshed with a tooth portion at the tip of the oscillating gear, and a rotatively supported on the base of the wiper shaft And a wiper motor comprising a balance plate that holds the meshing state between the tooth portion of the swing gear and the output gear, and a cover that covers the opening of the case.
The tip end portion of the support shaft is projected outward from the base portion of the swinging gear, and a disc-shaped cap is attached to the tip end portion of the projecting support shaft. The surface of the surface of the disc-shaped cap facing the cover At least a part of the disc-shaped cap is slidably brought into contact with the cover, and the radius of the disc-shaped cap is formed to be larger than the dimension from the center line of the support shaft to the outer periphery of the base of the swing gear. A wiper motor characterized in that the outer peripheral surface of the large-diameter cap is brought close to the side wall of the case in a state where the wiper is stopped at a fixed position.

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