JPS6322052Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a nut runner for tightening screw parts at high speed and low torque and at low speed and high torque.

<Prior art> Nut runners that tighten threaded parts at high speed, low torque, and low speed, high torque have a large reduction ratio (for example, 1/
100 to 1/200), methods have been used in which a plurality of known planetary gear devices are arranged in series in the axial direction, or a method in which a harmonic drive device and a planetary gear device are combined. however,
All of these problems lead to an increase in the size and weight of the nut runner, and also to an increase in the number of component parts.

The object of the present invention is to provide a nut drive that is small and lightweight, has a large reduction ratio, and is quiet.

<Structure of the invention> In order to achieve the above-mentioned object, the invention meshes a sun gear formed on an input shaft with a thin-walled cylindrical planetary gear whose hollow interior is filled with an elastic material, and this planetary gear has a number of teeth. A fixed internal gear and a movable internal gear having a difference are meshed with each other, and the forward rotation of the input shaft by the drive motor drives the rotary shaft at high speed and low torque through the first one-way rotation clutch. The reverse motion of the input shaft by the motor is transmitted at a reduced speed to the movable internal gear, and the rotation of the movable internal gear drives the rotary shaft to rotate at low speed and high torque via a second one-way rotating clutch. This is what I did.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, reference numeral 10 indicates a mounting frame, and this mounting frame 10 includes a fixed housing 1.
1 is fixed to the fixed housing 11, and a movable housing 12 is rotatably supported on the fixed housing 11. A rotary shaft 13 is rotatably supported on the movable housing 12 concentrically with the rotation axis of the movable housing 12,
A drive shaft 14 is slidably engaged with one end of the rotary shaft 13 by a spline, and is normally held at the forward end position by the repulsive force of a spring 15. Drive shaft 1
A socket 16 that engages with a threaded part such as a bolt is attached to the tip of the bolt 4.

An input shaft 21 on which a sun gear 20 is formed is rotatably supported on the movable housing 12 on the same axis as the rotating shaft 13. The drive motor 22 is connected to a drive motor 22 . Input shaft 21
The other end is connected to the rotating shaft 13 via a one-way rotating clutch 23.
3 transmits rotation to the rotary shaft 13 only when the input shaft 21 rotates normally. The sun gear 20 has two planetary gears 24 arranged on its diameter line.
25 are meshed with the sun gear 20 so as to be able to revolve and rotate on its axis, and a fixed internal gear 26 with the sun gear 20 fixed concentrically to the planet gears 24 and 25 in the movable housing 12 is connected to the planet gears 24 and 25. They are engaged over approximately 1/2 of the total length. A movable internal gear 27 is meshed with the remaining portions of the planetary gears 24 and 25. The movable internal gear 27 is rotatably supported in the movable housing 12 concentrically with the fixed internal gear 26, and is configured as a shifted gear having a number of teeth 2n (n is an integer) smaller than the fixed internal gear 26. ing. One end of the movable internal gear 27 is coupled to the rotary shaft 13 via a one-way rotary clutch 28, and the one-way rotary clutch 28 transmits rotation to the rotary shaft 13 only when the movable internal gear 27 rotates in the normal direction. It's getting old.

The fixed housing 11 has a cap 3 on its outer surface.
A cap 30 is removably fixed to the movable housing 12, and a bending rod 31 is provided between the cap 30 and the movable housing 12. The bending rod 31 is bent by the rotation of the movable housing 12 caused by the reaction force during screw tightening, and the bending of the bending rod 31 is detected by a sensor such as a strain gauge, making it possible to manage the screw tightening torque.

The planetary gears 24 and 25 do not have support shafts, and only the sun gear 20 and the two internal gears 26 and 27 mesh with each other.
7, and is positioned in the axial direction by a pair of thrust plates 33, 34. Because of this support configuration, the sun gear 20 and the planet gears 24, 25 have increased axial widths to improve the stability of supporting the planet gears 24, 25.

Further, as shown in FIG. 2, the planetary gears 24 and 25 are formed into thin cylindrical shapes in order to reduce the weight of the planetary gear mechanism.
The hollow interiors of 4 and 25 are filled with cylindrical elastic bodies 35 and 36 made of rubber or plastic by press-fitting.

In the above configuration, when the drive motor 22 is started in normal rotation, the rotation of the input shaft 21 is directly transmitted to the rotating shaft 13 via the one-way rotating clutch 23, and the rotating shaft 13 is driven at high speed and low torque. Ru.
When the drive motor 22 is started in reverse, the rotation of the input shaft 21 causes the planetary gears 24, 2
5 is rotated between the sun gear 20 and the fixed internal gear 26 and revolved counterclockwise in FIG. is rotated at a low speed, and the rotation of this movable internal gear 27 is caused by a one-way rotating clutch 28.
The rotation shaft 13 is driven at low speed and high torque. In this case, the reduction ratio i
The number of teeth of sun gear 20 is Z1, and the number of teeth of fixed internal gear 2 is
When the number of teeth of the movable internal gear 27 is Z2 and the number of teeth of the movable internal gear 27 is Z3, it is determined by the following formula, and the maximum reduction ratio is obtained when (Z2-Z3)=2.

i=(1+Z2/Z1)(Z3/Z3-Z2) By the way, when the planetary gears 24 and 25 are made into a thin cylindrical shape to reduce weight, it has been recognized that considerable noise is generated during rotational driving. By filling the hollow interiors with elastic bodies 35 and 36, noise can be significantly reduced, and it has been demonstrated that this is effective in reducing noise without sacrificing weight reduction.

<Effects of the Invention> As described above, the nut runner of the present invention has the following advantages.

(1) Since a large reduction ratio can be obtained using one set of planetary gear mechanisms, the number of parts can be significantly reduced, and the device can be made lighter and smaller.

(2) Since the planetary gear is made into a thin cylindrical shape and its hollow interior is filled with elastic material, noise generation can be suppressed without sacrificing weight reduction.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view of a nut runner, and FIG. 2 is a cross-sectional view of the nut runner shown in FIG.
It is an enlarged sectional view taken along the line. 11, 12...housing, 13...rotating shaft,
14... Drive shaft, 16... Socket, 20... Sun gear, 21... Input shaft, 22... Drive motor,
23, 28...One-way rotating clutch, 24, 25
... Planetary gear, 26 ... Fixed internal gear, 27 ...
Movable internal gear, 35, 36... elastic body.

Claims (1)

[Claims for Utility Model Registration] (1) A housing, a rotating shaft rotatably supported by the housing, a drive shaft connected to the rotating shaft so as to be relatively slidable and having a socket at its tip, and the housing. an input shaft rotatably supported on the same axis as the rotating shaft and having a sun gear formed on its outer periphery; and a first one-way rotating clutch that transmits rotation to the rotating shaft only when the input shaft rotates in the normal direction. , a planetary gear meshed with the sun gear, and a fixed internal gear fixed to the housing concentrically with the input shaft and meshed with the planetary gear.
a movable internal gear that is rotatably supported on the housing concentrically with the input shaft, has a tooth number difference from the fixed internal gear, and meshes with the planetary gear; and only when the movable internal gear rotates in the normal direction. The planetary gear includes a second one-way rotating clutch that transmits rotation to the rotating shaft, and a drive motor that rotates the input shaft in the forward and reverse directions. Nuttranna is filled with. (2) Two of the planetary gears are arranged on the diameter line of the sun gear, and the movable internal gear has a difference in the number of teeth by two from the fixed internal gear. Natsutranna as mentioned.