JPH03157551A - Worm gearing - Google Patents

Abstract

PURPOSE:To keep off any backlash over a long period of time by constituting each gear tooth with a tooth part and a shaft part being engaged in a state of sliding contact with teeth in the specified range, and having this shaft part pressed-in a hole part via a bearing. CONSTITUTION:Each gear tooth member 2 consists of a tooth part 21 and a shaft part 22 being engaged in a state of sliding contact with a tooth 11 in the specified range. This part 22 is pressed-in a hole part 31 via a bearing 32. In an interval between this bearing 32 and the shaft part 22, there is provided with an axial traveling allowance in a closely fitted state. A compression spring 34 is interposed between a bottom part of the hole part 31 and a tip of the shaft part 22. In a state that the gear tooth member 2 and a worm 1 are engaged with each other, the most advanced position of the gear tooth member 2 is set up so as to have the member 2 slightly thrust in the axial direction. Thus, any backlash is preventable for a long period of time.

Description

[Detailed Description of the Invention] [Field of Application and Summary of the Invention] The present invention relates to a worm gear device, and particularly to a worm gear device that can prevent backlash at the meshing portion between a worm and a worm wheel. A member corresponding to the teeth of the worm wheel (@ member) is held on the periphery of the wheel so that it can move forward and backward, and is biased in the advancing direction to prevent the above-mentioned backlash and the backlash between the tooth member and the wheel. be.

[Prior art and its problems] Worm gears are often used as transmission mechanisms for speed reduction devices and index tables. Recently, there has been a strong demand for improved transmission accuracy, and it has become a major issue to prevent backlash at the meshing portion between the worm and the worm wheel in the worm gear.

To prevent this backlash,
It is conceivable to use the technology disclosed in the above publication.

As shown in Fig. 5, the device described in this publication consists of a drum-shaped worm (1) and a worm wheel (less than H , simply called a wheel (HH)).

In this conventional device, a hole (3) is provided on the circumferential side of the disk (3).
1) The (31) are arranged radially at a predetermined pitch, and the shaft (21) of the bottle tooth (20) is rotatable through the hole (31) (:H) via the bearing (32). The wedge member (K) for adjusting the supporting position is pivoted into the hole (
31), and a sphere (B) is interposed between this bearing (32) and the tip of the shaft (21).

According to this conventional device, the meshing precision between the shape of the pin teeth (20) and the tooth profile of the worm (1) is improved, and each pin tooth (
By adjusting the degree of protrusion of 20), backlash at the engagement portion between the worm (1) and the wheel (HH) can be prevented. However, in this conventional device, backlash occurs when the meshing part between the pin tooth (20) and the tooth (11) of the worm (1) wears out due to long-term use. It cannot be used if it does not occur.

The present invention consists of a ``drum-shaped worm (1)'' and a wheel (H)I) that meshes with the worm, and this wheel (H)I) is provided with a toothed member on the circumferential side of the disk (3). (2) (2) is arranged radially at a predetermined pitch, and the tooth member (2) (2) is attached to the worm (1).
In the "Woom gear device" which is designed to mesh with the tooth (11) of the tooth member (2), by focusing on the rotation of the tooth member (2), there is no risk of backlash occurring over a long period of time, and moreover, the tooth member (2) and the tooth The task is to ensure smooth engagement with (11).

In order to solve this problem, the present invention cleverly takes advantage of the fact that the lead angle of the drum-shaped worm (1) changes to provide teeth that are held in a press-fit state with respect to the disk (3). Even if the tooth member (2) is the tooth member (2), the tooth member (2) is the tooth (11
) is configured so that it is biased in the advancing direction when engaged.

[Technical Means] The technical means of the present invention taken to solve the above problems is that each tooth member (2) is connected to a tooth portion (21) that meshes with the tooth (11) in a sliding contact state. Holes (31) are formed radially at a predetermined pitch on the circumferential side of the disk (3), and the shaft portion (22) is
) is press-fitted into the hole (31) through the bearing (32), and an allowance for movement in the axial direction is provided between the bearing and the shaft (22) in a state in which they are tightly fitted. A compression spring (34) is interposed between the bottom of the shaft (31) and the tip of the shaft (22), and when the tooth member (2) and the worm (1) are engaged, the tooth member (2) 1. The most advanced position of the tooth member (2) is set so that it is pushed in slightly in the axial direction.

[Effect] The above technical means of the present invention operates as follows.

The wheel (HH) and the worm (1) are some of the tooth members (2) (2) out of a large number of tooth members (2) (2).
) and teeth (11) are in a state of meshing, and the worm (1
) is transmitted to the wheel (HH). Warm (
Since 1) is drum-shaped, the lead angle of i (11) is not constant. Therefore, when the wheel (HH) rotates due to transmission with the worm (1), the tooth member (2) changes its posture in accordance with the change in the lead angle while being pushed from the engagement start position to the engagement end position. changes.

In other words, the shaft portion (22) rotates at a certain angle depending on the lead angle.

Here, the tooth member (2) has a compression spring (34) interposed between the bottom of the hole (31) and the tip of the shaft (22).
A protruding force in the radial direction is applied due to the biasing force of There is plenty of room for movement. Further, the advanced position of the tooth member (2) is set at a position that protrudes from the position of the tooth member (2) in the meshed state.

Therefore, the shaft portion (22) is rotated very slightly and is subjected to a biasing force in the advancing direction, and the tooth member (
2), when the shaft portion (21) is engaged with the teeth (11), it always tries to be located at the most extended position. In other words, it acts to eliminate backlash between the teeth (11) and the shaft (21).

If the bearing (32) is a needle bearing,
Although it is difficult for the shaft (22) to move in the axial direction, even if the shaft (22) is press-fitted into this type of bearing (32), if the shaft (22) rotates, it will not move in the axial direction. Since the motion proceeds smoothly, the backlash removal effect is not reduced.

[effect] Since the present invention has the above configuration, it has the following unique effects.

The shaft (22) of the tooth member (2) is press-fitted into the hole (31) of the disk (3) via the bearing (32), and the shaft (21) is in an engaged state. Since the tooth member (2) is always urged in the advancing direction, backlash does not occur at the meshing portion between the shaft portion (21) and the teeth (11). Further, even if the meshing portions are worn out due to long-term use, a backlash-free meshing state is ensured accordingly, so backlash does not occur for a long period of time.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

In the first embodiment shown in FIGS. 1 to 3, the shaft portion (21) of the tooth member (2) is configured in a chevron shape, and the entire tooth member (2) is made of a material with sufficient hardness. There is. and,
As shown in FIG. 3, the surface of the shaft portion (21) is surrounded by a metal material (M) having a certain thickness.

The shaft portion (22) of the tooth member (2) has a groove (35) of a constant width around its base end and near the tip.
A large number of steel balls (31) are located between the bottom of the disc (3) and the inner peripheral surface of the hole (31) (31) formed radially on the circumferential side of the disc (3).
38) (36) is inserted in a press-fitted state. Therefore, the tooth member (2) is rotatably and in rolling contact between the shaft portion (22) and the hole portion (31). Further, the tooth member (2) has an 8-movement allowance in the axial direction in accordance with the transfer allowance of the steel balls (31i) (36) with respect to the width of the groove (35).

The tip of the shaft (22) faces the bottom wall of the hole (31),
A disc spring serving as a compression spring (34) is stacked between the two in the axial direction. Then, the disc spring and the shaft portion (22
) is interposed with a flat washer.

In this embodiment, the cross section of the shaft (21) is similar to that of the worm (1).
The shaft portion ( The height of the shaft (21) is set, and when it is engaged with the drum-shaped worm (1), both sides of the shaft (21) have teeth (11) (11).
) is in contact with the side of the

Further, the tooth member (2) is biased in the axial direction (protrusion direction) by the action of the disc spring as the compression spring (34), and is rotatably held by the steel balls (36) (36) as the bearing (32). be done.

In this embodiment, the tooth member (2) is entirely made of a material with sufficient hardness, and the groove (
A through hole (37) (37) for inserting a steel ball (36) is provided at a position opposite to the screw plug (35).
8) are screwed together. Therefore, after storing the disc spring as the compression spring (34) in the bottom of the hole (31), the shaft (22) of the tooth member (2) is inserted to a predetermined depth and the through hole (37) ( A predetermined number of steel balls (3B) from 37) (
3B), and then insert a screw plug (3B) into each through hole (37).
38), the tooth member (2) will be supported by the rolling bearing mechanism (bearing (32)).

Further, since the shaft portion (21) is covered with the metal material (M), the friction at the contact portion between the shaft portion (21) and the teeth (11) is also reduced.

Regarding the shape of the shaft portion (21) of the tooth member (2), as shown in FIG. (11) It is also possible to have a shape with so-called troughs, which have contact surfaces that come into contact with each other on both sides.

In addition, as for the bearing structure of the shaft (22), in addition to the structure using steel balls (3B) (36) as in the above embodiment, a needle bearing is used between the shaft (22) and the hole (31). It may also be configured to be press-fitted between it and the peripheral surface. When using this double bearing, the shaft portion (22) may have a size similar to that from the base end to the distal end.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the main parts of the embodiment of the present invention, Fig. 2 is a sectional view taken along line XX, Fig. 3 is an explanatory diagram of the tooth member (2) used therein, and Fig. 4 is an explanatory diagram of the tooth member (2). An explanatory diagram of another example, FIG. 5 is an explanatory diagram of a conventional example. 1...Worm H...Wheel 3...Disc 2...Tooth member 11)...Tooth 21...Tooth part 22...Shaft part 31...Hole part 32...Bearing 34... Compression spring

Claims (1)

[Claims] A drum-shaped worm (1) and a wheel that engages with it (H
), and this wheel (H) is connected to the disc (3).
Teeth members (2) (2) are implanted radially at a predetermined pitch on the circumferential side of the worm (1), and the tooth members (2) (2) are engaged with the teeth (11) of the worm (1). In the worm gear device, each tooth member (2) is replaced with a tooth (11).
It consists of a tooth part (21) and a shaft part (22) that mesh with each other in a certain range of sliding contact, and holes (31) (31) are opened radially at a predetermined pitch on the circumferential side of the disk (3). , the shaft (22) is inserted into the hole (3) via the bearing (32).
1), and provide a margin for movement in the axial direction in a tightly fitted state between this bearing and the shaft (22), so that the bottom of the hole (31) and the tip of the shaft (22) A compression spring (34) is interposed between the tooth member (2) and the worm (1) so that the tooth member (2) is slightly pushed in the axial direction when the tooth member (2) and the worm (1) are engaged. Worm gear device with the most advanced position set