JPH11153210A - Scissors gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide desired scissors force. SOLUTION: On mutual assemblage surfaces of a main gear 2 and a subsidiary gear 3, a main side spring support part 7 and a subsidiary side spring support part 8 are provided to be integrally formed with both gears 2, 3. Both end parts 4a, 4b of a scissors spring 4 assembled to be held between both gears 2, 3 are respectively semi-circularly protruded. Abutment parts 7a, 8a are formed on side surfaces of both spring support parts 7, 8 to be abutted against both end parts 4a, 4b of the scissors spring 4 to support both end parts 4a, 4b. On the back side of both abutment parts 7a, 8a, inclined surfaces 7b, 8b of which foot parts are enlarged in width toward a base bottom part are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scissor gear to which any scissor force can be applied.

[0002]

2. Description of the Related Art A gear is used as one of power transmission means. However, usually, a gap is formed between the tooth surfaces of the meshed gears, and backlash as backlash in the rotation direction of the gear often occurs. Are known. It is also well known that the scissors gear is an effective gear for reducing such backlash (for example, see Japanese Unexamined Patent Publication No.
No. 1099961).

FIG. 5 is an exploded perspective view of a conventional scissors gear 101. As shown in FIG. The scissor gear 101 generally includes a main gear 102 and a sub gear 103, and a scissor spring 104.
It is constituted by sandwiching. The main gear 102 and the sub gear 103 are provided with fitting openings 107 and 108 in the form shown in FIG. 5, respectively, and the fitting openings 107 and 108 are provided with the ends 104a and 104b of the scissor spring 104, respectively. Fixing pins 105 and 106 for fixing are fitted.

That is, as shown in FIG. 6, which is a partial sectional view of a scissor gear 101, a scissor spring 1
04 is supported by its ends 104a, 104b abutting against the fixing pins 105, 106.
Therefore, in such a scissors gear 101,
The elastic force due to the bending of the scissors spring 104 generates an urging force (hereinafter, referred to as a scissor force) acting on the sub gear 103 in the rotation return direction, and meshes the meshing teeth of the mating gear with the main gear 102 and the sub gear 103. , So that backlash can be reduced.

[0005]

FIG. 7 is a diagram showing the state of FIG.
When the scissors force T1 due to the scissors spring 104 is relatively small, the fixing pin 106 withstands the scissors force T1 applied from the side surface of the scissor spring 104 and does not bend, as shown in an enlarged view of a cross section taken along line AA of FIG. . Therefore, the scissors spring 104 can be stably supported by contacting the end portion 104b of the scissor spring 104 with the contact surface S1 having a large area on the side surface of the fixing pin 106.

However, when a large scissor force T2 is generated by the scissor gear 101 in order to further enhance the effect of reducing the backlash, as shown in FIG. 8, the fixing pin 106 cannot withstand the scissor force T2 and is greatly bent. Sometimes.

In this manner, when the fixing pin 106 is bent, the scissors force T2 is transmitted to the sub gear 103 into which the fixing pin 106 is fitted by tilting, and the scissor force T2 is transmitted to the main gear 102 by the distortion of the sub gear 103. There may be a gap between the sub gear 103 and the sub gear 103. Such a gap causes deterioration of gear noise, and also impairs the assemblability of the scissor gear 101.

Further, when the fixing pin 106 is bent, the side surface of the fixing pin 106 and the scissor spring 1
04 comes into contact with the end portion 104b with a small contact surface S2. That is, by supporting the large scissors force T2 on the contact surface S2 having a small area, the abrasion of the contact surface S2 remarkably progresses, and the durability and reliability of the scissors gear 101 such as breakage of the fixing pin 106 are impaired. There is also a risk. Therefore, the conventional scissors gear 10
In the case of No. 1, the scissors force that can be given is greatly limited by the durability of the fixing pins 105 and 106.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a scissor gear which can impart an arbitrary scissor force and is excellent in reliability and durability.

[0010]

According to a first aspect of the present invention, there is provided a main gear having a main gear and a sub gear on a side surface of the main gear to which a biasing force is applied by a scissor spring in a rotation returning direction. The main gear and the sub-gear sandwich a mating gear between the main gear and the sub-gear, and a spring supporting portion for supporting each end of the scissor spring is integrally formed on the mounting surface of the main gear and the sub-gear. That is the gist.

[0011] According to this configuration, the rigidity can be given to the same portion through the spring support portion which is formed integrally and protrudes. For this reason, reliability and durability can be improved with respect to any scissors force. Further, the number of parts as the scissor gear can be reduced.

According to a second aspect of the present invention, in the scissors gear according to the first aspect, the spring supporting portion is formed to have an inclined surface extending in a base portion direction on a back surface of a contact surface with the scissor spring. The gist is that it is done.

According to this configuration, even when the spring supporting portion is formed to project with a small volume, the rigidity according to the bending moment applied to the spring supporting portion can be easily and accurately provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a scissor gear embodying the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the scissors gear 1 is constituted by sandwiching a scissor spring 4 between a main gear 2 and a sub gear 3 as in the conventional scissor gear 101. The main gear 2 is a disk-shaped helical gear having teeth formed on the outer peripheral surface thereof, and a through hole 5 is formed at the center of the main gear 2 for assembling to a mounting shaft. A cylindrical portion 6 having a cylindrical shape protrudes around the through hole 5 on the side of the main gear 2 to be attached to the sub gear 3. A main-side spring support 7 is also formed on the surface of the main gear 2 to be assembled to the sub-gear 3. The main-side spring support portion 7 is provided with an abutment portion 7a which is a concave wall formed perpendicular to a surface to be assembled to the sub gear 3. An arc-shaped guide wall 7c is formed from the contact portion 7a toward the outer periphery. An inclined surface 7b is formed on the back surface of the contact portion 7a so that the base becomes wider at the base as described later.

The sub gear 3 is a disk-shaped helical gear having the same diameter as the main gear 2 and has a main gear 2 on its outer peripheral surface.
The same number of teeth and the same standard are formed. Sub gear 3
A through hole 9 is formed at the center of the main gear 2 so as to be able to engage with the outer peripheral surface of the cylindrical portion 6 of the main gear 2. A sub-side spring support portion 8 is formed on the surface of the sub-gear 3 to be attached to the main gear 2. Similarly to the main-side spring support portion 7, the sub-side spring support portion 8 is a contact portion 8 that is a concave wall formed perpendicular to the mounting surface to the main gear 2.
a is provided. An arc-shaped guide wall 8c is formed from the contact portion 8a toward the outer periphery. An inclined surface 8b is also formed on the back surface of the contact portion 8a so that the base becomes wider at the base.

The scissors spring 4 has an annular shape with a part missing, and is made of a material having a high elasticity.
At each end of the scissors spring 4, convex ends 4a and 4b formed in a semicircular shape are formed.

Next, the assembly structure of the scissors gear 1 will be described. FIG. 2 is a partial cross-sectional view of the scissor gear 1, and FIG. 3 is a cross-sectional view taken along line BB of FIG. The end 4a of the scissors spring 4 is in contact with the contact portion 7a of the main-side spring support portion 7 provided on the main gear 2, and the other end 4b is in contact with the contact portion 8a of the sub-side spring support portion 8. It is arranged so as to be in contact with. Then, the sub-gear 3 is assembled so that the through-hole 9 of the sub-gear 3 passes through the cylindrical portion 6 of the main gear 2. Thus, the scissors gear 1
The main gear 2 and the sub gear 3 are assembled in the form of a single gear that is overlapped so as to be relatively rotatable along the axis.

When meshing with a mating gear as the scissors gear 1, first, the main gear 2 and the sub gear 3 are shifted in phase on the same axis, and the respective ends 4a, 4b of the scissors spring 4 supported by the two gears 2, 3 respectively. The scissors spring 4 is flexed by widening the distance between the springs. The scissors gear 1 generates a scissors force T3 in the rotation return direction due to the elastic force generated by the bending of the scissors spring 4. Then, a bending moment due to the scissors force T3 is applied to each of the contact portions 7a and 8a.

The details are described below in the scissors spring 4
This will be described with reference to FIG. 4 which is an enlarged view of the contact portion between the end portion 4b of FIG. When assembling the scissors gear 1, the contact portion 8a of the sub-side spring support portion 8
The end portion 4b of the scissors spring 4 that abuts against the contact portion 8a by the scissor force T3 of the scissor spring 4. The scissors force T3 generates a bending moment M1 in the sub-side spring support portion 8. The bending moment M1 generated in the sub-side spring support 8 increases as it approaches the base. The sub-side spring support portion 8 can withstand the bending moment M1 by the inclined surface 8b formed on the back surface of the contact portion 8a so as to be thicker toward the base.

The manner of assembling the scissor gear 1 with the mating gear is the same as that of the conventional scissor gear 101, and a description thereof will be omitted. Next, effects of the scissors gear 1 of the above-described embodiment will be described below.

Contact portions 7 of the respective spring support portions 7 and 8
A sloped surface 7b, 8b was formed on the back surface of each of a and 8a. By forming these inclined surfaces 7b, 8b, it is possible to provide the spring support portions 7, 8 that can withstand the bending moment M1 applied to each of the spring support portions 7, 8. Further, since the spring support portions 7 and 8 withstand the bending moment M1, the two gears 2 and 3 are hardly deformed. Further, by preventing deformation of both gears 2 and 3, assemblability can be improved, and gear noise generated when scissor gear 1 rotates can be reduced.

When the conventional scissors gear 101 is assembled, the recesses formed at the ends 104a and 104b of the scissor spring 104 abut against the diameters of the fixing pins 105 and 106 fitted into the two gears 102 and 103. Had to be set up. However, in the scissors gear 1 of the present embodiment, each end 4a, 4b of the scissor spring 4 is merely disposed near the contact portions 7a, 8a of the spring support portions 7, 8 formed on the two gears 2, 3. so,
When the two gears 2 and 3 are shifted in phase, the guide walls 7c and 8c can guide the ends 4a and 4b to the contact portions 7a and 8a. Therefore, the assembling work of the scissors gear 1 can be simplified.

In the scissors gear 1 of the present embodiment, the spring supports 7 and 8 instead of the fixing pins 105 and 106 are formed integrally with both gears 2 and 3, so that the fixing pin 1
05 and 106 can be eliminated, and the number of parts of the scissors gear 1 can be reduced. In addition, the number of work steps for fitting the fixing pins 105 and 106 into the fitting holes 107 and 108 can be reduced, so that the labor for assembling the scissors gear 1 can be reduced. In addition, since the fixing pins 105 and 106 are eliminated, the fixing pins 105 and 10 due to scissor force are eliminated.
Since there is no possibility of causing breakage of the scissors 6, the durability and reliability of the scissors gear 1 can be improved.

The above embodiment may be modified as follows, and the same operation and effect can be obtained in such a case. In the present embodiment, the inclined surfaces 7 are provided on the back surfaces of the contact portions 7a and 8a.
Although the b and 8b are formed, the inclined surfaces 7b and 8b may be omitted as long as the spring support portions 7 and 8 have sufficient rigidity against the scissor force applied to the scissor gear 1.

In the present embodiment, the guide walls 7c, 8c are provided on the respective contact portions 7a, 8a, but may be omitted. In the present embodiment, the arc-shaped guide walls 7c, 8c are provided from the respective contact portions 7a, 8a toward the outer periphery. However, the arc-shaped guide walls may be provided toward the inner periphery.

In the scissors gear 1 of the present embodiment, a semicircular convex portion is formed at each end 4a, 4b of the scissor spring 4, and the scissor spring 4 comes into contact with the spring support portions 7, 8 formed on both gears 2, 3. Although the scissors spring 4 is supported by the spring supporting portions 7 and 8 by making the contact portions 7a and 8a concave portions and making the two concave and convex portions abut, the formation of these concave portions and convex portions may be reversed.

In the present embodiment, the helical gear is formed on the main gear 2 and the sub gear 3, but a spur gear may be formed. Next, technical ideas other than the claims that can be grasped from the above embodiment will be described together with their effects.

[0029] The scissors gear according to claim 1 or 2, wherein the spring supporting portion has a guide wall forming a recess in the spring supporting portion.

According to this configuration, when the phases of both gears are shifted, each end of the scissor spring is guided to the respective spring support by the guide wall.

[0031]

As described above in detail, according to the first aspect of the present invention, it is possible to provide the same portion with any rigidity through the spring support portion which is formed integrally and protrudes. Become like For this reason, reliability and durability can be improved with respect to any scissors force.
Further, the number of parts of the scissor gear can be reduced.

According to the second aspect of the present invention, even when the spring supporting portion is formed to project from a small volume, the rigidity according to the bending moment applied to the spring supporting portion can be easily and accurately provided. be able to.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a scissors gear according to an embodiment of the present invention.

FIG. 2 is a plan view showing a partial cross section of the scissors gear.

FIG. 3 is a sectional view of the scissors gear, taken along the line BB in FIG. 2;

FIG. 4 is an enlarged view of a spring supporting portion on the sub gear side of the scissor gear and a contact portion of the scissor spring.

FIG. 5 is an exploded perspective view of a conventional scissors gear.

FIG. 6 is a plan view showing a partial cross section of the scissors gear.

7 is an enlarged cross-sectional view taken along line AA of FIG. 6 of the scissor gear that has generated a small scissor force.

FIG. 8 is an enlarged cross-sectional view taken along line AA of FIG. 6 of the scissor gear that has generated a large scissor force.

[Explanation of symbols]

1 ... scissors gear, 2 ... main gear, 3 ... sub gear, 4
... scissors spring, 7 ... main side spring support part, 8 ... sub side spring support part, 7a, 8a ... contact part, 7b, 8b ... inclined surface, 7c, 8c ... guide wall.

Claims (2)

[Claims] A scissors gear having a main gear and a sub gear on a side surface of the main gear to which a biasing force is applied by a scissor spring in a rotation returning direction, wherein a mating gear meshed with the main gear is held between the main gear and the sub gear. 2. The scissors gear according to claim 1, wherein spring support portions for supporting the respective ends of the scissor spring are integrally formed and protruded from the assembling surfaces of the main gear and the sub gear. 2. The scissors gear according to claim 1, wherein the spring supporting portion is formed to have an inclined surface extending toward a base portion on a back surface of a contact surface with the scissor spring. Scissors gear.