JPH0523978B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a worm wheel for a wiper motor that can be used in a wiper motor equipped with a speed reduction mechanism, and is particularly suitable for a wiper device that makes reciprocating motion. It is something.

(Prior art) Conventionally, in order to downsize the wiper motor and increase the reduction ratio, a reduction mechanism in which a worm and a worm wheel are engaged is often used in wiper motors. The wiper arm is reciprocated through a link crank mechanism formed by the link connecting rod and the link arm.

(Problem to be Solved by the Invention) However, in the above-described conventional wiper motor, the reduction mechanism formed by the worm and the worm wheel has a structure in which the worm and the worm wheel are connected to each other in order to smoothly transmit the rotation of the worm to the worm wheel. Although there is a separation between
When the wiper arm reverses, the moment of inertia of the wiper arm acts on the worm wheel,
Since the worm wheel temporarily drives the worm, there is a problem in that the worm and the worm wheel collide with each other due to the backlash caused by the bumping, resulting in noise.

Therefore, the present invention has been made by focusing on the above-mentioned conventional problems.When the wiper arm reverses, the bump between the worm and the worm wheel is reduced to zero, thereby preventing the generation of noise during reversing. The purpose of the present invention is to provide a worm wheel for a wiper motor that can perform the following functions.

[Structure of the Invention] (Means for Solving the Problems) The structure of the worm wheel for a wiper motor according to the present invention to achieve the above object is such that a worm and a worm wheel are engaged to form a speed reduction mechanism, and a link In a wiper device that converts the rotation of the worm wheel into reciprocating motion through a reciprocating motion and swings the wiper arm back and forth between two reversed positions,
It is characterized by having flexible portions for engagement with the worm at two locations on the outer periphery spaced apart by 180 degrees.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention.

That is, the reference numeral 1 in the figure is the wiper motor, 2 is the rotating shaft of the wiper motor 1, and 3 is the rotating shaft 2.
4 is a worm wheel that meshes with the worm 3; 5 is a fixed shaft that pivotally supports the worm wheel 4; the worm 3 and the worm wheel 4 form a speed reduction mechanism.

10 is a link connecting rod (link) rotatably connected to the worm wheel 4;
1 is a link arm (link) rotatably connected to the link connecting rod 10; the worm wheel 4, the link connecting rod 10, and the link arm 11 form a link mechanism; A reciprocating rocking motion is given to the wiper arm 15 and the wiper blade 16 attached to the tip of the wiper arm 15.

Furthermore, the worm wheel 4 is manufactured by resin molding, and the worm wheel 4
In this example, two notches 21 are provided at the inverted position of the wiper arm 15, that is, at a position within a 180 degree range from which the wiper arm 15 reciprocatingly swings is inverted. This notch 21 is
The gear portion is flexible in the radial direction of the worm wheel 4 and has an opening on the outer periphery so as to be easily bent, and a space is bent in the rotational direction on the inner periphery side of the opening. Then, the notch 21
A cushion rubber 22, which is an elastic member, is inserted into. This cushion rubber 22 presses the gear part bent by the notch 21 in the outer diameter direction, and presses the gear part in the load direction (for example, when the wiper arm 15 is locked by an external force such as snow). This protects the gear part when excessive torque is applied to the tooth surface from (e.g.).

The wiper device configured as described above includes a wiper arm 15 that swings back and forth and a wiper blade 1.
6 is reversed, the gear part that is pressed in the outer radial direction by the cushion rubber 22 and slightly protrudes from the other parts is affected by the elasticity of the resin and the load of the cushion rubber 22, as shown in FIG. Due to the absorbency, the worm wheel 4 engages with the worm 3 and deflects in the radial direction, so that the backlash between the worm 3 and the worm wheel 4 can be reduced to zero.

Therefore, even if the moment of inertia generated when the wiper arm 15 is reversed is applied to the worm wheel 4 connected via the link mechanism, the gear portion corresponding to the reversed position of the wiper arm 15 will be affected by the elasticity of the resin and the cushion. Since the worm 3 is biased by the elasticity of the rubber 22, there is no rattling between the worm 3 and the worm wheel 4, which prevents the generation of noise and ensures smooth operation. Torque transmission becomes possible.

In this embodiment, the elastic member inserted into the notch 21 is described as the cushion rubber 22, but an elastic member such as a spring that can press the gear portion against the worm 3 may also be used. It is not limited to the rubber 22.

Next, FIG. 3 is a diagram showing another embodiment of the present invention. In this embodiment, the cushion rubber 22 explained in the previous embodiment is omitted, and the gear part of the worm wheel 4 corresponding to the inverted position of the wiper arm 15 is pressed against the worm 3 by the notch 21 only by the elasticity of the resin. , the gear part is the worm 3
When the gears mesh, the gears in question are deflected,
In addition to smoothing the engagement between the worm 3 and the worm wheel 4, it also eliminates the backlash between the worm 3 and the worm wheel 4 when the wiper arm 15 is reversed, and because the number of parts can be omitted, excessive external It is suitable to use when no torque is generated.

Next, FIG. 4 is a diagram showing still another embodiment of the present invention, in which a hollow portion 31 is provided at a position of the worm wheel 4 corresponding to the inverted position of the wiper arm 15 to provide flexibility in the radial direction. At the same time,
The gear part provided with the hollow part 31 is made to protrude slightly, so that when the wiper arm 15 is reversed, the worm 3
Since the gear portion corresponding to the inverted position of the wiper arm 15 is bent, the meshing between the worm 3 and the worm wheel 4 is smoothed, and the bending occurs. Since the gear portion is not cut out as in the previous embodiment, it is suitable for use in wiper motors that generate excessive torque from the outside.

[Effects of the Invention] As explained above, the wiper motor wheel according to the present invention has a worm and a worm wheel that are engaged with each other to form a deceleration mechanism, and converts the rotation of the worm wheel into reciprocating motion via a link to reduce the speed of the wiper arm. In a wiper device that swings the wiper arm back and forth between two inverted positions, two portions on the outer periphery spaced apart by 180 degrees corresponding to the inverted positions of the wiper arm are provided with flexible portions for engagement with the worm. With this configuration, when the wiper arm is reversed, the bump between the worm and the worm wheel can be set to zero, and when the wiper arm swings outside the reverse position, the worm and the worm wheel can be set to zero. Since it is possible to restore the backlash between the two positions to a predetermined value, an excellent effect can be obtained in that the wiper arm can be smoothly reciprocated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a wiper device equipped with a wiper motor worm wheel according to an embodiment of the present invention, FIG. 2 is a cross-sectional explanatory diagram showing the meshing state of FIG. Explanatory diagram showing the wiper motor worm wheel according to the embodiment, No. 4
The figure is an explanatory diagram showing a worm wheel for a wiper mower according to still another embodiment of the present invention. 3...Worm, 4...Worm wheel, 1
0, 11... Link (link connecting rod, link arm), 15... Wiper arm, 21... Notch, 22... Cushion rubber, 31... Hollow part.

Claims (1)

[Claims] 1. A wiper in which a worm and a worm wheel are engaged with each other to form a deceleration mechanism, and the rotation of the worm wheel is converted into reciprocating motion via a link to reciprocate and swing the wiper arm between two inverted positions. A worm wheel for a wiper motor, characterized in that a worm wheel for a wiper motor is provided at two locations on the outer periphery spaced apart by 180 degrees corresponding to the inverted position of the wiper arm, and is flexible for engagement with the worm. 2. The worm wheel 4 for a wiper motor according to claim 1, wherein the worm wheel engages with the worm at a gear with substantially zero backlash when the wiper arm is reversed. 3. The worm wheel for a wiper motor according to claim 1 or 2, wherein the radially flexible portion of the worm wheel is formed by a notch. 4. The worm wheel for a wiper motor according to claim 1 or 2, wherein the radially flexible portion of the worm wheel is formed by a hollow portion. 5. Claim 1 or 2, wherein the radially flexible portion of the worm wheel is formed by a combination of a notch and an elastic member inserted into the notch. Worm wheel for wiper motor as described in section.