JPS6129222B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor speed reduction device that reduces the rotational speed and transmits rotational force through a worm provided at one end of the rotational shaft of the motor and a worm gear meshed with the worm. It is something. The present invention
In particular, this motor speed reduction device is particularly suitable for being installed in a wiper motor for vehicles such as automobiles.

A speed reduction device in which a worm is provided at one end of the rotating shaft of a motor and transmits the rotational force of the motor through a single worm gear provided in mesh with the worm is known, and conventionally, it has been used as a speed reduction device for wiper motors. It was used. This conventional motor speed reduction device will be explained with reference to FIG. 1. A worm 5 is provided at one end of the motor rotating shaft 4 to which the rotor 3 of the motor 1 is fixed, and a worm gear 6 is arranged in mesh with the worm 5. The deceleration device 2 is configured by the following.
10 is an output shaft fixed to a worm gear.
The motor rotating shaft 4 is supported by bearings 7 and 8, and a thrust bearing 9 absorbs thrust in the axial direction. In such a conventional speed reduction device, due to its structural essence, when transmitting the rotational force of the motor to the output shaft 10, the rotational force of the motor is transmitted from the worm gear 6 to the worm gear 6 in a direction perpendicular to the worm shaft (arrow A).
A reaction force acts on the worm 5 in the direction). In particular, when the load is large or the rotational speed is high, this reaction force increases and the worm 5, while being supported by the bearings 7 and 8, bends in a curved manner in the direction of arrow A. This increased wear and improper meshing caused increased wear on the worm and worm gear. In the wiper motor,
It is common to use a worm gear made by resin molding for reasons such as weight reduction and ease of manufacture, but as a reduction gear used in a wiper motor, it is necessary to take sufficient measures against wear as described above. There is sex.

The present invention eliminates the drawbacks of the prior art as described above,
Regardless of the magnitude of load and rotational speed, the worm and worm gear can always be maintained in an appropriate meshing state, minimizing wear on the worm gear and improving the transmission efficiency of rotational force from the motor rotation shaft to the output shaft. It is an object of the present invention to provide a motor speed reduction device that can maintain a constant high value. A feature of the present invention is that at least one pair of worm gears are disposed on both sides of the worm in mesh with the worm to prevent deflection of the worm as much as possible, thereby achieving smooth transmission of rotational force and protection of the bearing. By doing so, the reduction gear can be used for a long period of time. Furthermore,
When a pair of worm gears is used, a first stacked gear in which a worm gear and a first gear are coaxially fixed is disposed so that the worm gear meshes with the worm, and a worm gear and a second gear are similarly connected. and a second lap gear coaxially fixed to the worm are disposed on the opposite side of the first lap gear with respect to the worm so that the worm gear of the second lap gear is in mesh with the worm, and By configuring the first gear of the first overlap gear and the second gear of the second overlap gear to be in direct mesh, the driving force from the worm is always divided into two regardless of how the output is extracted. Half of the driving force is transmitted to each worm gear, and then combined by direct meshing with the first gear and second gear, and transmitted to the outside from the output shaft, resulting in proper adjustment of the worm and worm gear. This maintains a good meshing state and enables highly efficient transmission of rotational force.

Before the present invention, for example,
There are prior art techniques described in Japanese Patent Application Laid-open No. 1344582 and Japanese Patent Application Laid-Open No. 53-27005, but these are aimed at eliminating bumps between the worm and the worm gear, and the first gear and the second gear are Instead of directly meshing, a special mechanism is interposed between the two, and as a result, one of the worm gears receives the driving force necessary to eliminate the backlash of the entire driving force, which is similar to the present invention. It is not possible to maintain proper meshing between the worm and the worm gear.

Hereinafter, one example of implementation of the present invention will be described with reference to the drawings. In the embodiment shown in FIG. 2, the same components as in FIG. 1 are given the same reference numerals. As shown in FIG. 2, a pair of lapped gears 12 and 13 are disposed on both sides of the worm 5 in the speed reduction device 11. The first lap gear 12 includes a worm gear 12a and a first gear 1 which are both fixed to a shaft 12c.
2a, and the worm gear 12a is in mesh with the worm 5. A second lap gear 13, which is arranged on the opposite side of the worm 5 from the first lap gear 12, similarly has a worm gear 13a and a second gear 13b both fixed to the shaft 13c,
The worm gear 13a is in mesh with the worm 5. Therefore, when the rotary shaft 4 is rotated by the motor 1 and the worm 5 is rotated, the first and second lap gears 12 and 13 are rotated in opposite directions to drive and rotate the shafts 12c and 13c, respectively. At this time, the output can be taken out from one of the shafts 12c and 13c.

According to the present motor speed reduction device having the above configuration, the worm is prevented from being bent due to the reaction force of the worm gear, and the transmission efficiency of rotational force is improved. Furthermore, since the worm is prevented from being bent, no excessive force is applied to the bearing, thereby reducing wear. The worm is supported at multiple points by the worm gear, so regardless of how the output is taken out, the worm can always maintain an appropriate meshing state with the worm gear, allowing for balanced and ideal transmission of rotational force. becomes. Further, the present invention can be constructed from ordinary parts such as a worm and a worm gear without any special processing on the components, and the manufacturing cost is not only low but also extremely easy to manufacture.

Furthermore, since the driving force from the worm is dispersed, the module of the gear can be made smaller, so the gear can be made smaller, and since small gears are placed on both sides of the worm, the motor can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a conventional motor speed reduction device, and FIG. 2 is a partial sectional view showing a motor speed reduction device according to an embodiment of the present invention. Explanation of symbols of main parts, 5: Warm, 11:
Reduction gear, 12, 13: overlap gears.

Claims (1)

[Claims] 1. A first stacked gear in which a worm gear and a first gear are coaxially fixed is arranged so that the worm gear meshes with a worm that is driven and rotated by a motor,
At the same time, a second stacked gear in which a worm gear and a second gear are coaxially fixed is disposed on the opposite side of the worm from the first stacked gear, and the worm gear is meshed with the worm; A motor characterized in that the first gear and the second gear are directly meshed, and one of the shaft to which the first overlap gear is fixed or the shaft to which the second overlap gear is fixed is used as an output shaft. reduction gear.