JP3302545B2 - Worm gear reducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a worm gear reduction device used for a pickup feeding device mounted on a disk reproducing device such as a D or a disk reproducing recording device such as an MD.

[0002]

2. Description of the Related Art An example of a conventional worm gear reduction device will be described below with reference to FIG. In the figure, the worm gear reduction device includes a motor 101 as a drive source, a worm gear 103 as a worm press-fitted to a drive shaft 102 of the motor 101, and a worm gear 1.
A helical gear 104 serving as a worm wheel arranged to mesh with the helical gear 03; a spur gear 105 arranged on the helical gear 104 to rotate together with the helical gear 104 to extract torque; The thrust adjusting unit 10 is arranged with a slight gap from the thrust adjusting unit 10 for adjusting the movement of the drive shaft 102 in the axial direction.
6 and a fixing portion 107 for fixing the motor 101 and the thrust adjusting portion 106.

The helical gear 104 and the spur gear 10
5, a half of the engagement length between the worm gear 103 and the helical gear 104 is defined as L1 (L
1 ′), when half the length of the worm gear 103 is L2 (L2 ′), L1 (L1 ′) and L2 (L
2 ′), L1 (L1 ′) <L2 (L2 ′)
It has become.

In the above configuration, the rotational driving force generated by the motor 101 is transmitted to the worm gear 103 via the drive shaft 102, and the worm gear 103 rotates. Since the worm gear 103 meshes with the helical gear 104, the rotational driving force of the worm gear 103 is
4 and the helical gear 104 rotates. At this time, since the worm gear 103 receives the reaction force from the helical gear 104, the drive shaft 102 moves in the axial direction, but the thrust adjustment unit 106 adjusts the movement. Thereby, the movement of the drive shaft 102 in the axial direction can be avoided, so that the performance of the motor 101 can be maintained.

If the number of the worm gear 103 is Zw and the number of teeth of the helical gear 104 is Z, the rotational speed of the helical gear 104 is reduced to Zw / Z with respect to the rotational speed of the worm gear 103. Is spur gear 105
Is taken out through.

[0006]

However, as shown in FIG. 5, the teeth 1 at both ends of the worm gear 103 are arranged.
03a and 103b are formed at an acute angle,
One end of each of 3a and 103b is very sharp and thin. Therefore, when the worm gear 103 is molded by filling a mold with a moldable material,
The teeth 103a and 103b may be deformed at the time of opening the mold, and the teeth 103a and 103b less than the set dimensions may be formed due to insufficient filling of the material.
The worm gear 10 is formed by cutting metal or the like.
In the case of processing No. 3, the teeth 103a and 103b may be deformed when cutting both ends of the worm gear 103.

On the other hand, as shown in FIG. 6, in order to reduce the size of the worm gear reduction device, the lengths of the drive shaft 102 and the worm gear 103 may be reduced. That is, the relationship between L1 (L1 ′) and L2 (L2 ′) described above is expressed as L1 (L1 ′).
(L1 ′)> L2 (L2 ′), and by shortening L3, the worm gear reduction device is downsized. Note that L
Reference numeral 3 denotes a length from the center A to a rear end 106a opposite to the end of the thrust adjustment unit 106 facing the front end of the drive shaft 102.

However, if the lengths of the drive shaft 102 and the worm gear 103 are reduced, the deformed teeth 103a and 103b do not mesh properly with the helical gear 104. For this reason, the teeth 103a and 103b interfere with the teeth of the helical gear 104 and do not rotate smoothly, thereby generating noise. Therefore, by shortening the engagement length L1 (L1 ') between the worm gear 103 and the helical gear 104, There is a problem that the worm gear reduction device cannot be downsized.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a worm gear reduction device capable of suppressing the generation of noise even when downsized.

[0010]

In order to solve the above-mentioned problems, a worm gear reduction device according to a first aspect of the present invention includes a combination of a worm and a worm wheel, and a driving force is transmitted from the worm to the worm wheel. In the worm gear reduction device, the teeth at both ends of the worm have an inclined surface whose outer shape becomes smaller toward the end, and the inclined surface has the teeth at least from the tooth tip.
Also the above worm module x 2
It is characterized by being formed by being performed .

According to the above configuration, by forming the inclined surface, a sharp and thin portion does not exist at the tip of the tooth. For this reason, when molding the worm by filling the mold with a moldable material, it is possible to prevent the deformation of the teeth that occurred when the mold is opened, and set due to insufficient filling of the material. There is no danger that teeth smaller than the dimensions will be molded. Further, even when the worm is machined by cutting a metal or the like, it is possible to prevent the deformation of the teeth generated during the cutting.

As a result, even if the engagement length between the worm and the worm wheel is shortened to reduce the size of the worm gear reduction device, the worm rotates smoothly without interfering with the worm wheel. Can be suppressed. Further, since the size of the worm can be reduced, the material cost can be reduced, and the cost can be reduced.

[0013]

Further, since the inclined surface is formed by being chamfered warm modules × 2 away from the tooth tip of the worm, the thin portion of the thickness of the teeth are deleted. As a result, the above-described deformation of the teeth does not occur, and teeth less than the set dimensions are not molded.

As a result, noise can be suppressed even if the engagement length between the worm and the worm wheel is further shortened and the worm gear reduction device is further downsized.

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, in a worm gear reduction device 1 of the present invention, a driving force of a motor 2 is transmitted from a worm gear 4 as a worm to a helical gear 5 as a worm wheel. The worm gear 4 is press-fitted to the drive shaft 3 of the motor 2, and is disposed so as to mesh with the helical gear 5. A spur gear 6 is arranged on the helical gear 5 so as to rotate with the helical gear 5 and take out torque. Further, the worm gear reduction device 1 is provided with a thrust adjusting portion 7 arranged with a slight gap from the tip of the drive shaft 3 and a fixing portion 8 for fixing the motor 2 and the thrust adjusting portion 7. ing. The thrust adjusting unit 7 adjusts the movement of the drive shaft 3 in the axial direction due to the reaction force from the helical gear 5 to the drive shaft 3 and the worm gear 4, and avoids the adverse effect on the motor 2 due to the movement of the drive shaft 3. This is to maintain the performance of the motor 2.

The center of rotation of the helical gear 5 and the spur gear 6 is defined as a starting point, and half of the meshing length between the worm gear 4 and the helical gear 5 is L1 (L1 '), while half of the length of the worm gear 4 is half. When L2 (L2 ′) is set, the relationship between L1 (L1 ′) and L2 (L2 ′) is L1 (L2 ′).
(L1 ′)> L2 (L2 ′).

Here, the worm gear 4 will be described in detail with reference to FIG. In the figure, the end faces 4c and 4d of the teeth 4a and 4b at both ends of the worm gear 4 are formed perpendicular to the drive shaft 3, and the teeth 4a and 4b
4b is chamfered. This chamfering is performed when the module of the worm gear 4 is m, and the teeth 4a and 4
The end faces 4c and 4d at a position m × 2 away from the tooth tip of b
And the teeth 4a and 4b are
It is formed in a shape whose outer shape becomes smaller toward the end faces 4c and 4d, that is, a so-called tapered shape. Thus, the teeth 4a and 4b are sharp and thin portions (B
Part) are all deleted.

In the above configuration, the rotational driving force generated by the motor 2 is transmitted to the worm gear 4 via the drive shaft 3, and the worm gear 4 rotates. Since the worm gear 4 meshes with the helical gear 5, the rotational driving force of the worm gear 4 is transmitted to the helical gear 5, and the helical gear 5 rotates. At this time, the drive shaft 3 and the worm gear 4 receive a reaction force from the helical gear 5, and the drive shaft 3 moves in the axial direction. However, since the thrust adjusting unit 7 adjusts the moving amount, there is no adverse effect on the motor 2.

Assuming that the number of the worm gear 4 is Zw and the number of teeth of the helical gear 5 is Z, the rotational speed of the helical gear 5 is reduced to Zw / Z with respect to the rotational speed of the worm gear 4, and the torque is reduced to a spur gear. 6 to be taken out.

By the way, at the tip of the teeth 4a and 4b,
Due to the above-described tapered chamfering, all the sharp and thin portions of the teeth 4a and 4b are deleted. For this reason, the teeth 4a and 4b are not deformed in the manufacturing process or the transport process of the worm gear 4 and the assembling process of the worm gear reduction device 1, so that the engagement length L1 (L) of the worm gear 4 and the helical gear 5 is not changed.
Even if the worm gear reduction device 1 is downsized by shortening 1 ′), the teeth 4 a and 4 b rotate smoothly without interfering with the teeth of the helical gear 5.

Here, the worm gear reduction device 1 of the present invention
The noise suppression effect when using is described below with reference to FIG. The number of revolutions of the motor 2 is 10,000 rpm, the number of the worm gear 4, the module and the pitch circle are 1, 0.25 and φ0.25, respectively, and the module, the pitch circle and the number of teeth of the helical gear 5 are 0.25, 11.54 and 46
Is set to Further, the horizontal axis in the figure represents the above-described engagement length L1 (L1 ′), and the vertical axis represents noise generated when a constant load is applied to the spur gear 6 and a constant voltage is applied to the motor 2. Level.

Graph a shows the results when the above-mentioned teeth 4a and 4b are chamfered at a position m × 2 away from the tooth tips to form a tapered shape. Graph b shows the above teeth 4a.
This is the result of chamfering 4b at a position m × 1 away from the tooth tip to form a tapered shape. Graph c shows the results when the above-mentioned teeth 4a and 4b are not chamfered.

In the same graph, the graph a shows that when the meshing length becomes Xa or less, the noise level which has been constant until then suddenly increases, while the graph c shows that when the meshing length becomes Xc or less. The noise level, which was constant until then, rises sharply. When Xa is compared with Xc, it is found that Xa <Xc.

Therefore, the above-mentioned teeth 4a and 4b are chamfered at a distance of m × 2 from the tooth tips and formed in a tapered shape, so that the meshing length is shortened and the worm gear reduction device 1 is reduced in size. However, noise generated due to interference between the teeth 4a and 4b and the teeth of the helical gear 5 is suppressed.

Further, in the graph b, when the engagement length becomes Xb or less, the noise level which has been constant until then rapidly increases. However, this Xb is
Xc, there is almost no difference from the above-mentioned teeth 4a, 4
Even if chamfering is performed at a position m × 1 away from the tooth tip of b and the tapered shape is formed, the above-described noise generated when the worm gear reduction device 1 is downsized cannot be suppressed. The reason for this is that in the chamfering at a position mx1 away from the tooth tip, the thin portions of the teeth 4a and 4b are not completely deleted.

As described above, the teeth 4a and 4b at both ends of the worm gear 4 are chamfered at a position away from the tooth tip of the worm gear 4 by a module × 2 of the worm gear 4, and are formed in a tapered shape. The sharp and thin portions of the teeth 4a and 4b are deleted.

As a result, in the worm gear reduction device 1 according to the present invention, even if the mesh length is reduced and the worm gear reduction device 1 is reduced in size, the worm gear reduction device 1 is caused by the interference between the teeth 4a and 4b and the teeth of the helical gear 5. Noise can be suppressed. Further, since the material of the worm gear 4 can be reduced by reducing the length of the worm gear 4, the cost can be reduced.

The teeth 4a and 4b may be formed as shown in FIG. That is, in the same figure, the teeth 4a and 4b
Is chamfered in an arc shape bulging outward,
The radius of this arc shape is m × 2. As a result, all the sharp and thin portions (part B) of the tooth tips are deleted. For this reason, even if the mesh length is shortened and the worm gear reduction device 1 is downsized, the teeth are reduced. 4a
4b rotates smoothly without interfering with the teeth of the helical gear 5.

As a result, even if the tips of the teeth 4a and 4b have an arc shape with a radius of the module × 2, the tooth 4a
Since the sharp and thin portions of 4b are deleted, the same effects as those described above can be obtained.

[0037]

As described above, the worm gear reduction device according to the first aspect of the present invention is a worm gear reduction device in which a worm and a worm wheel are combined and a driving force is transmitted from the worm to the worm wheel. The teeth at both ends have inclined surfaces whose outer shape becomes smaller toward the ends, and the inclined surfaces are
The inscribed tooth is at least from the tip of the worm module ×
This is a configuration formed by chamfering two positions apart .

As a result, even if the engagement length between the worm and the worm wheel is shortened and the worm gear reduction device is downsized, the worm rotates smoothly without interfering with the worm wheel. This has the effect of being able to be suppressed. Further, since the size of the worm can be reduced, the material cost can be reduced and the cost can be reduced.

[0039]

Further, by further shortening the meshing length of the worm and the worm wheel, be further downsized worm reduction gear, an effect that it is possible to suppress the generation of noise.

[0041]

[0042]

[0043]

[0044]

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of a worm gear reduction device of the present invention.

FIG. 2 is an enlarged plan view of a worm gear of the worm gear reduction device shown in FIG. 1;

FIG. 3 is a graph illustrating a relationship between a distance from a center of a helical gear of the worm gear reduction device illustrated in FIG. 1 to an end surface of the worm gear and a noise level.

FIG. 4 is an enlarged plan view of another worm gear.

FIG. 5 is a plan view showing a schematic configuration of a conventional worm gear reduction device.

6 is a plan view showing a schematic configuration of the worm gear reduction device shown in FIG. 5 when the engagement length between the helical gear and the worm gear is reduced.

[Explanation of symbols]

 Reference Signs List 1 worm gear reducer 4 worm gear (worm) 4a tooth 4b tooth 5 helical gear (worm wheel)

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 55/00-55/30 F16H 1/00-1/26

Claims (1)

(57) [Claims] In a worm gear reduction device in which a worm and a worm wheel are combined and a driving force is transmitted from the worm to the worm wheel, the teeth at both ends of the worm are inclined such that the outer shape becomes smaller toward the ends. Surface and its inclined surface
Means that the teeth are at least
Formed by chamfering at a distance of 2 x
Worm gear reduction gear, characterized in that are.