JPH05118409A - Worm gear device - Google Patents

Abstract

PURPOSE:To permit the use of a worm gear device at a place where precision is required, by eliminating the ricketiness due to backlash. CONSTITUTION:A worm 3 meshed with a worm wheel 4 is divided into two gear half bodies 3A and 3B, and these two gear half bodies 3A and 3B are attached from the opposed sides on the tooth surface of the worm wheel 4 by a coil spring 14 interposed between two gear half bodies 3A and 3B, and the backlash between the worm wheel 4 the worm 3 is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a worm gear device including a worm and a worm wheel which mesh with each other.

[0002]

2. Description of the Related Art Generally, a worm gear is used for transmitting a rotation having a large reduction ratio between two shafts which are perpendicular to each other and are not twisted, and is composed of a worm and a worm wheel which mesh with each other. Also, usually a worm is used as the original car. And withstand high loads,
Due to its simple axis conversion, it is currently used in the traveling axis of a traveling transport robot and in a speed reducer such as a lifter for moving a transported object up and down. Further, there are various kinds of worm gears, for example, a cylindrical worm gear 43 including a cylindrical worm 41 and a cylindrical worm wheel 42 as shown in FIG.
Alternatively, as shown in FIG. 4, there is a drum-shaped worm gear 46 composed of a drum-shaped worm 44 and a drum-shaped worm wheel 45. However, both of the worm gears are arranged to facilitate rotation between the worm and the worm wheel. A gap, that is, a backlash is provided between the meshed teeth, and the backlash is always used.

[0003]

Therefore, in the conventional worm gear, since backlash is always present between the teeth meshing with each other, backlash easily occurs between the two shafts, and accuracy is required. There is a problem in that the places that can be used are restricted, such as not being able to use the parts that are used. Also, when the input shaft rotation is switched between forward and reverse rotation, the direction of the input shaft thrust direction changes each time this is switched, and a large thrust load is applied to the motor, etc. installed on the input shaft each time. Therefore, there is a problem that the bearing may damage the bearing of the motor or the like due to this load, or may be worn to shorten the life. Further, as a method of eliminating backlash, for example, a method of horizontally moving the worm gear together with the input shaft and adjusting the meshing ratio of the worm and the worm wheel can be considered. However, in general, worm gears have a structure in which the worm and worm wheel are constantly exposed to lubricating oil in the gear box, so
The seal structure between the gearbox and the input shaft becomes complicated,
There is a problem that the device itself becomes expensive.

The present invention has been made in view of the above problems, and its purpose is to eliminate backlash due to backlash without a simple structure and to use it in a place where accuracy is required, which is inexpensive and improves versatility. It is to provide a worm gear device that can be operated.

[0005]

In order to achieve the above object, a worm gear device according to the present invention divides at least one of a worm or a worm wheel meshed with each other into two gear halves, and the two gear halves. Biasing means for pressing the body against the tooth surface of the worm wheel or the worm from opposite directions are provided.

[0006]

According to this construction, the two gear halves are pressed against the worm or worm wheel by the biasing means so as to push or pull each other via the worm or worm wheel. Therefore, there is virtually no backlash between the worm or worm wheel and the two gear halves. Therefore, there is no backlash between the worm and the worm wheel, and a highly accurate worm gear device can be easily obtained.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration sectional view showing an embodiment of a worm gear device according to the present invention. In the figure, the worm gear device 1 includes a gear box 2, and a worm 3, a worm wheel 4 meshed with the worm 3, and the like are arranged in the gear box 2. In the gear box 2, lubricating oil 5 is put so that the worm wheel 4 can be used.

More specifically, the worm wheel 4
Is attached to an output shaft 6 rotatably arranged across the gear box 2 in the front-rear direction so as to rotate integrally with the output shaft 6. On the other hand, Worm 3
Is mounted on an input shaft 7 which is arranged in a state of crossing the gear box 2 in the left-right direction and being substantially orthogonal to the output shaft 6 so as to rotate integrally with the input shaft 7.
Both ends of the input shaft 7 are rotatably supported by the gear box 2 via bearings 8. On the input shaft 7, the oil rings 9 are provided close to the bearings 8.
a, 9b and a bearing holding plate 11 are attached. Furthermore, the worm 3 has two gear halves 3A, 3A at approximately the middle portion thereof in the direction along the input shaft 7.
The gear halves 3A and 3B are meshed with each other in a state of intersecting the worm wheel 4 at a substantially right angle. Of these, one gear half 3A is formed integrally with the input shaft 7. On the other hand, the other gear half 3
B is mounted on the input shaft 7 via a bearing 12 and rotates integrally with the input shaft 7 with respect to the rotation direction, but in a direction along the input shaft 7 (arrow F-R in FIG. 1). Direction) is ready to move freely. In addition, on the input shaft 7, an E ring 13 is arranged on the gear half 3B side, and a coil spring 14 as a biasing means is compressed between the E ring 13 and the gear half 3B. It is installed. The coil spring 14 constantly applies a force in the direction of arrow F in FIG. 1 to the gear half 3B to remove the backlash between the worm 3 and the worm wheel 4.

FIG. 2 is a diagram for explaining that the backlash between the worm 3 and the worm wheel 4 can be removed by interposing the coil spring 14. Here, in order to simplify the description, the main part structure is schematically shown. Therefore, the components in FIG. 2 designated by the same reference numerals as those in FIG. 1 are the same components as those in FIG. Therefore, the principle by which the backlash between the worm 3 and the worm wheel 4 can be removed will be described with reference to FIG. First, in FIG. 2 (a),
In the state where the coil spring 14 is not mounted on the input shaft 7, both gear half bodies 3A and 3B of the worm 3 are meshed with the worm wheel 4. Further, the input shaft 7 is in a state in which the bearing 8 and the bearing restraining plate 11 prevent the input shaft 7 from moving in the thrust direction, and only allow rotation. In this state, the worm wheel 4
There is a play indicated by the symbol d between the tooth surface 4a of the gear half 3A and the tooth surface 3a of the gear half 3A, and a symbol D is shown between the tooth surface 4b of the worm wheel 4 and the tooth surface 3b of the gear half 3B. I'm ready to play. When the worm 3 is rotated together with the input shaft 7 in this state, the rotation transmitted from the gear halves 3A and 3B to the worm wheel 4 side causes the worm 3 to play d or D (this play is equal to the above d). It depends on the direction of rotation) whether or not it becomes the above-mentioned D), and it is transmitted until it becomes a state in which it is absorbed, and after that, it is transmitted to the worm wheel 4 side, and a response delay occurs with respect to the following. Further, the existence of this play d or D causes rattling between the worm 3 and the worm wheel 4. Therefore, the coil spring 14 is mounted in a compressed state between the gear half 3B and the E ring 13, and the force for pushing the gear half 3B toward the gear half 3A, that is, FIG.
When a force in the direction indicated by arrow F is applied, the gear half 3B
The tooth surface 3b of the worm wheel 4 is brought into contact with the tooth surface 4b of the worm wheel 4, and the worm wheel 4 is also denoted by F in FIG.
Press in the direction indicated by. Then, this worm wheel 4 also moves in the direction of arrow F along with the half gear 3B.
The tooth surface 4a of No. 3 moves until it comes into contact with the tooth surface 3a of the gear half 3A, and the play d and D disappears as shown in FIG. That is, it is possible to obtain the worm gear device 1 having no backlash and good followability. The force in the arrow F direction can be adjusted by changing the spring force of the coil spring 14.

In the above embodiment, the coil spring 14 is mounted between the gear half 3B and the E ring 13, and the gear half 3B is pressed together with the worm wheel 4 toward the gear half 3A. , The coil spring 14 is mounted between the gear half 3A and the gear half 3B, and the gear half 3B together with the worm wheel 4 is located inside the arrow F direction shown in FIGS. The structure may be such that the worm wheel 4 is pressed against the worm wheel 4 while being pressed outward in the direction opposite to the arrow F direction shown in (b) and (c). In addition, the worm 3 side has two gear halves 3A,
Although the structure divided into 3B is disclosed, the worm wheel 4
There is no problem even if the side is divided into two in the cylindrical direction and the worm 3 is restrained from the left and right.

[0011]

As described above, according to the worm gear device of the present invention, the two gear halves are pushed or pulled by the urging means through the worm or the worm wheel, so that the worm or the worm can be pulled. As it is pressed against the wheel, there is virtually no backlash between the worm or worm wheel and the two gear halves. Therefore, rattling between the worm and the worm wheel is eliminated, and a highly accurate worm gear device can be easily obtained. As a result, an inexpensive and highly accurate worm gear can be provided, and at the same time, it can be used in a wide range of fields and the versatility is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration sectional view showing an embodiment of a worm gear device according to the present invention.

FIG. 2 is a diagram for explaining that the worm gear device shown in FIG. 1 can eliminate backlash.

FIG. 3 is a perspective view showing an example of a conventional cylindrical worm gear.

FIG. 4 is a perspective view showing an example of a conventional hourglass-shaped worm gear.

[Explanation of symbols]

 1 Worm gear device 3 Worm 3A Gear half 3B Gear half 4 Worm wheel 14 Coil spring (biasing spring)

Claims (1)

[Claims] 1. A worm and a second mounted on the first shaft.
A worm gear device in which worm wheels mounted on the shaft of the worm mesh with each other, at least one of the worm or the worm wheel is divided into two gear halves, and the two gear halves are the worm wheel or worm. A worm gear device characterized in that it is provided with biasing means for press-contacting the tooth surfaces of the two in opposite directions.