JPS6049152A - Gear reduction device - Google Patents

Abstract

PURPOSE:To obtain better accurate feed at a high reduction ratio in a narrow installation space by engaging two planetary gears to a sun gear directly connected to a driving source so as to revolve both planetary gears around the sun gear at an identical speed. CONSTITUTION:A pinion 30 serving as a sun gear and directly connected to a rotational driving source 26 transmits rotation force to a first planetary gear 34, and the planetary gear 34 rotates while engaging with the pinion 30 and a stationary inner gear 32 and revolves around the sun gear 30 to rotate a retainer 48. While a second planetary gear 42 is engaged with the pinion 30 and a rotary inner gear 36, and further rotates by effect of rotation of the retainer 48 and revolves around the sun gear 30 at an identical speed to that of the first planetary gear 34 to transmit rotation force to the rotary inner gear 36. By this planetary gear mechanism, better accurate feed can be obtained at a high reduction ratio in a narrow installation space.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gear reduction device, and more particularly to a gear reduction device that uses a planetary gear mechanism and can obtain a high reduction ratio.

In general, when the reduction ratio of a gear reduction device is high, for example, about 1/60, if the reduction ratio is a float reduction device consisting of a gear mechanism, the number of gears increases, and the reduction mechanism There is a problem that the installation space becomes large.

In order to solve these problems, a gear reduction device that utilizes a planetary gear mechanism and can obtain a high reduction ratio as shown in FIG. 1 has been proposed. That is, a drive shaft 12 is directly connected to the drive source 10, and a pinion 14 is provided on the drive shaft 12. Around this pinion 14, a fixed internal gear 16 and a rotating internal gear 18 are arranged around the pinion 14.
are arranged, and this pinion 14 and internal gears 16 and 18
A common planetary gear 20 is meshed between them. That is, the normal loose M gear 20 is the fixed internal gear 16 and the fixed internal gear]
However, by rearranging the rotating internal gear 18, the number of teeth is slightly changed compared to the fixed internal gear 16, and the planetary gear 20 meshes with both internal gears 16.8. I try to mesh with 18. Also, planetary gear 2
The rotary shaft 22 of 0 is pivotally supported by a retainer 24 as an arm member. Although only one planetary gear 20 is shown in FIG. 1, a plurality of identical planetary gears are pivotally supported on this retainer 24 at predetermined intervals. The gear reduction device configured as described above can obtain a large reduction ratio using a planetary gear mechanism.

However, in the conventional gear reduction device, the rotating internal gear 18 is forcibly meshed with the M star gear 20 by shifting the gears, so the planetary gear 20 and the internal gear 18 mesh with each other with a slight distance from each other compared to normal meshing. Therefore, hacklash cannot be removed and precise meshing cannot be achieved. Therefore, for example, if you want to obtain a precise feed pitch, for example, 100
When used in a magnetic disk writing or reading head feeding mechanism that performs pinch feeding in micron increments, the gear reduction device shown in FIG. 1 is not satisfactory in terms of accuracy.

The present invention was made in view of the above circumstances, and an object of the present invention is to propose a gear reduction device that can obtain accurate feed with a high reduction ratio.

In order to achieve the above object, the present invention includes a sun gear connected to a drive source, at least one first planetary gear that meshes with the sun gear and meshes with a fixed internal gear, and a fixed internal gear. output rotating internal gears arranged intermittently, at least one second planetary gear meshing with the sun gear and meshing with the rotating internal gears, a first planetary float, and a second planetary float. and an arm member pivotally supported so as to revolve around the sun gear at the same speed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the gear reduction device according to the present invention will be described in detail below with reference to the accompanying drawings.

2 and 3 show the structure of the float reduction device according to this embodiment, and the stepping motor 2 is used as the rotational drive source.
6 is provided with a drive shaft 28, and this drive shaft 28 is provided with a pinion 30 as a sun gear. Around the pinion 30, there is an internal gear 32 fixed to the pinion 30.
is located. A first planetary gear 34 meshes with the pinion 30 and the fixed internal gear 32. Further, an output rotary internal gear 36 is arranged between the fixed internal gear 32 and the fixed internal gear 32 . This rotating internal gear 36 is pivotally supported by a frame 38 via a shaft 40. A second planetary gear 42 meshes with the pinion 30 and the rotating internal gear 36. In this way, the first planetary gear 34 meshes with the pinion 30 and the fixed internal gear 32, and the second planetary gear 42 meshes with the pinion 30 and the rotating internal gear 3.
It meshes with 6.

This first planetary gear 34 is provided with a shaft 44 , and the second planetary gear 42 is further provided with a shaft 46 , and this shaft 44 is provided with a shaft 44 .
．． 46 is pivotally supported by a retainer 48 as a common arm member. The rotary internal gear 36 has external teeth 49 formed on its outer periphery and is used as an output extraction gear.The operation of the embodiment according to the present invention constructed as described above is as follows. First, the pinion 30 directly connected to the rotational drive source 10 transmits its rotational force to the first planetary gear 34, and the planetary gear 34 rotates on its own axis while meshing with both the pinion 30 and the fixed internal gear 32. It revolves around the surroundings and rotates the retainer 48. - The planetary gear 42 of the receiving box 2 meshes with the pinion 30 and the rotating internal gear 36, and also rotates under the influence of the rotation of the retainer 48 and rotates at the same speed as the first planetary gear 34. It revolves around the surroundings and transmits its rotational force to the rotating internal gear 36.

Next, the pinion 30 on the input end and the rotating internal gear 36 on the output side
The reduction ratio ρ is determined by the law.

Za・・・・・・Number of teeth of pinion 30 zb・・・
... Number of threads Zc of the first planetary gear 34 ...
... Number of teeth Zd of fixed internal gear 32 ...
・Number of threads Ze on the second planetary gear 42 Number of threads L on the rotating internal gear 36 Arm (
Retainer) (11 Zb = 15 Zc = 63 Zd = 16 Ze = 66 4 An extremely high reduction ratio can be obtained as described above.

In the embodiment shown in FIGS. 2 and 3, the first and second planetary gears 34 and 42 are provided on separate shafts with their positions shifted, but as shown in FIG. 52 may be provided coaxially with the respective planetary gears 34, 42 so as to be independently rotatable. In this case, the pinion 30 is formed into a two-stage tooth structure, and If154.56 is formed to mesh with the first and second planetary gears 34.42, respectively.

As explained above, according to the gear reduction device according to the present invention, a high reduction ratio can be obtained in a narrow installation space by using a planetary gear mechanism.

Further, according to the gear reduction device according to the present invention, the first planetary gear that meshes with the sun gear and the fixed internal gear, and the second planetary gear that meshes with the sun gear and the rotating internal gear are provided. Since the planetary gears mesh without shifting, highly accurate feed can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a gear reduction device using a conventional planetary gear mechanism, Fig. 2 is a sectional view showing the structure of the present embodiment, and Fig. 3 is a sectional view of the structure of the present embodiment shown in Fig. 2. An explanatory diagram showing the arrangement of gears, and FIG. 4 is a sectional view showing the structure of another embodiment. 26... Rotation drive source, 28... Drive shaft, 30.
...Binion as a sun gear, 32... Fixed internal gear, 34... First planetary gear, 36... Rotating internal gear, 42... Second 'M star gear, 48.・
・Retainer agent as arm month Patent attorney Kenzo Matsuura Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] a sun gear connected to a drive source; a fixed internal gear disposed around the sun gear intermittently with the sun gear; and at least one first gear that meshes with the sun gear and meshes with the fixed internal gear. a planetary gear, a rotating internal gear for output disposed intermittently with the fixed internal gear, a second planetary gear (one second planetary gear) that meshes with the sun float and also meshes with the rotating internal gear;
A gear reduction device comprising an arm member pivotally supported so that a first planetary gear and a second planetary gear can revolve around a sun gear at the same speed.