JPH0132600Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field of the Invention> This invention relates to a wiper drive device for a vehicle, particularly a wiper drive device for a small wiper such as an outside mirror wiper of an automobile.

<Prior art and its problems> FIGS. 1 and 2 show an example of a conventional wiper drive device for an outside mirror wiper. A worm 3 is attached to the motor 2 installed in the housing 1,
This meshes with worm gear 4. A first gear 5 is integrally formed at the lower part of the worm gear 4 and meshes with another second gear 6. A third gear 7 is integrally formed on the upper part of the second gear 6, and is further meshed with another fourth gear 8. A disk 10 is fixed to the drive shaft 9 to which the fourth gear 8 is fixed in a largely eccentric manner, and a proximal annular portion of the arm 11 is rotatably fitted onto the outer periphery of the disk 10. are doing. Arm 1
1 is rotatably connected to the tip of a lever 13 via a pin 12, and a square shaft of an output shaft 14 is fitted into a square hole at the center of the lever 13. .

Now, when motor 2 rotates in the specified direction,
The driving force is from the worm 3 to the gear train 4, 5,
6, 7, and 8, and the drive shaft 9 rotates. As a result, the disk 10 fixed to the drive shaft 9 rotates eccentrically and functions like a crank, and the tip of the arm 11 reciprocates to swing the lever 13, causing the output shaft 14 to rotate reciprocally. Therefore, by attaching a wiper to this output shaft 14,
The wiper device is completed.

However, in such a crank mechanism that converts unidirectional rotational motion into reciprocating rotational motion,
The maximum range of reciprocating rotation is 180 degrees, but if the lever 13 as described above is present, that range becomes even smaller. In the case of a wiper device, the wider the wiping range of the wiper, the better, so the reciprocating rotation range of the output shaft 14 is also set to be as wide as possible. As a result, the looseness caused by the deflection of each member constituting this drive device and the play between each component is concentrated on the final output shaft 14, resulting in the problem that the wiper does not operate smoothly. was.

<Purpose of the invention> This invention was made in view of the above-mentioned circumstances, and the object is to provide an improved wiper drive device that prevents rattling of the output shaft.

<Structure of the invention> The wiper drive device according to the invention includes a stopper for further regulating the position of the turning point of the output shaft defined by the crank mechanism.

<Description of Embodiments> Arm 11 of wiper drive device according to this invention
For example, as shown in FIG. 3, the proximal annular portion into which the eccentric disc 10 is rotatably fitted has the same shape as the conventional one, but its distal end is oriented laterally. and shoulder parts 1 that serve as stoppers on both sides.
1a and a shoulder portion 11b are formed. A hole 11c is formed in the center, and a lever 1 is inserted into the hole 11c.
A pin 12 fixed to 3 is rotatably fitted. On the other hand, lever 13 has lever 1 on its top surface.
3 is swung by the arm tip, a protrusion 13a that can be engaged with the shoulder stopper 11a at the arm tip and the other shoulder stopper 11b.
A protrusion 13b that can be engaged with is formed respectively.

Next, we will discuss the operation of this crank mechanism in the fourth section.
This will be explained with reference to the figures. First, when the eccentric disk 10 is located at its top dead center as shown in (A), the lever 13 is positioned so that the protrusion 13a of the lever 13 comes into contact with the shoulder stopper part 11a at the tip of the arm 11. . Next, when the eccentric disk 10 rotates 90 degrees clockwise as shown in (B), the connecting pin 12 between the arm 11 and the lever 13 is located approximately at the center of both the protrusions 13a and 13b of the lever 13. When the eccentric disk 10 further rotates 90 degrees clockwise and is located at its bottom dead center as shown in (C), the protrusion 13b of the lever 13 moves to another shoulder stopper portion 11 at the tip of the arm.
This corresponds to b. At this time, the output shaft 14 is urged to rotate clockwise by the inertia of the wiper connected to it, so this force is received by the shoulder stopper portion 11b at the tip of the arm via the protrusion 13b. Over-rotation of the output shaft 14 is prevented, and rattling when the eccentric disk 10 moves from its bottom dead center position and the output shaft 14 begins to rotate in the opposite direction is also prevented. In this way, when the eccentric disk 10 further rotates 90 degrees clockwise, the output shaft 1
4 is now rotated in the opposite direction, and the connecting pin 12 is positioned approximately at the center of both protrusions 13a and 13b again as shown in (D). When the eccentric disk 10 further rotates 90 degrees clockwise, it returns to the state shown in (A). At this time, since a counterclockwise inertia force is applied to the output shaft 14, this force is received by the shoulder stopper portion 11a at the tip end of the arm 11 via the protrusion 13a.

In the embodiment described above, a stopper for regulating the turning point position of the output shaft 14 is formed at the tip of the arm 11, but it may also be provided on another immovable member, and the stopper can be attached with a screw or the like. It is further preferred that the position be adjustable.

<Effects of the invention> As described above, the wiper drive device according to this invention is provided with an additional stopper to regulate the position of the turning point of the output shaft, so the wobbling of the output shaft is significantly reduced. Not only does the reciprocating rotational movement of the lever become smoother, but wear due to rattling is also prevented, greatly improving durability.

[Brief explanation of drawings]

Fig. 1 is a plan view of an example of a conventional wiper drive device with the top cover removed; Fig. 2 is a partially sectional front view of the device shown in Fig. 1; and Fig. 3 is a diagram of a wiper drive device according to this invention. FIG. 4, an exploded perspective view showing the crank mechanism section, is an explanatory diagram of the operation of the crank mechanism section shown in FIG. 3. 1...Housing, 2...Motor, 3...Worm, 4...Worm gear, 5-8...Gear, 9
... Drive shaft, 10 ... Eccentric disk, 11 ... Arm, 11a, 11b ... Shoulder stopper part, 12 ...
...Connection pin, 13...Lever, 13a, 13b...
...Protrusion, 14...Output shaft.

Claims (1)

[Scope of utility model registration request] A wiper drive device for converting rotational motion of a drive shaft in one direction into reciprocating rotational motion of an output shaft, the wiper drive device comprising a stopper for regulating the position of a turning point of the output shaft.