JPS58196356A - Positioner - Google Patents

Abstract

PURPOSE:To eliminate backlash and permit high-speed positioning by allowing the rotational movement of a pinion to be transmitted to a shaft through a flexible gear. CONSTITUTION:The rotational movement of the output shaft 25 of a motor permits the linear driving control of a shaft 20 through a pinion 26 and a flexible gear 24. Since the flexible gear is pressed onto the pinion 26 and the shaft 20 by a bearing 28 at this time, transmission free from backlash is permitted, and the rotational angular movement of a motor is transmitted to the shaft 20 correctly. In other words, when the distance between the both is varied by the swing of the pinion and the crook of the shaft 20, error is absorbed by the elastic deformation of the flexible gear 24. Therefore, generation of the surface pressure more than necessary and increase of the clearance can be suppressed. Thus, the rotational movement of the motor can be transmitted correctly to the shaft 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning device, and particularly aims at high-speed positioning without bank lashing.

In recent years, as a flexible automation tool,
Many automatic positioning devices using numerical control or the like have come into use. Pole screws are often used as positioning devices, but linear motors and the like are also being considered for higher speeds. The most typical positioning devices using ball screws are shown in Figures 1 and 2.
As shown in the figure, 1 is a table for positioning, and a well-known linear ball bearing is built into the table (not shown), which guides and slides on a shaft 3 supported by a bracket 2. let Further, a pole nut 5 is attached to the lower part of the table 1 via a bracket 4. Further, a ball screw 6 is engaged with the pole nut 6 via a steel ball. A steel ball (not shown) is
It circulates in the pipe 7 and is continuously supplied between the pole nut 6 and the ball screw 6. At both ends of the ball screw 6,
A bearing 8 and a bearing 9 support the ball screw so that it can rotate. These bearings 8 and 9 each have a bolt 10
．． 11, it is attached to the base. Furthermore, the right end of the ball screw 6 is connected to the output shaft of the motor 12 via a bearing 9.

Further, on the opposite side of the motor 12, a rotary encoder 1 is installed.
3 is attached to read the rotation angle of the motor 12 and convert it into an electrical signal. When the motor 12 rotates, its rotation angle is accurately detected by the rotary encoder 13, and the motor is controlled according to the output electric signal. The rotation of the motor is transmitted to the ball screw 6 and converted into linear motion.

The above is the principle of a positioning mechanism using a ball screw, which is commonly used in the past. This method uses a ball screw, so a major feature is that high positioning accuracy can be obtained, but due to structural problems such as the steel ball passing through the pipe 7, it is difficult to move at high speeds. It is said that it is difficult to carry out.

There are also other methods of positioning by modulating rotary motion into linear motion using a rack and pinion, but because of the backlash between the rack and pinion, it is not possible to perform highly accurate positioning. It is considered difficult to do.

The present invention eliminates these drawbacks of conventional positioning mechanisms and provides a positioning mechanism that is capable of achieving high speed and high accuracy. An embodiment of the present invention will be described below with reference to FIGS. 3 to 9.

14 is a fixed block, and by driving a motor 15 attached to this fixed block 14, shafts 19 and 20 supported at both ends by two brackets 17 and 18 are connected.
The aim of the present invention is to drive the motor in the left-right direction in FIG. The motor 16 is fixed to the main body 14 with screws 16, and a rotary encoder 2 is attached to the other end of the motor.
1 is attached with screws 22. Fixed block 14
Four slide bearings 23 are mounted inside and receive the shaft 19.20. A rack tooth surface is formed on the inside of the shaft 20, and a flexible gear 24 is formed on this tooth.
are meshing together. Here, the flexible gear 24 has a thin wall structure so that it can be slightly deformed in the radial direction. A pinion 26 mounted on the output shaft 25 of the motor 15 or a flexible gear 24 meshes with the shaft 2o. Inside the flexible/pull gear 24, there are four bearings that press the flexible gear in order to prevent its deformation and to eliminate some backlash between the flexible gear and the shaft 20 and between the flexible gear and the pinion 26. Four shafts 27 with 28 fixed to the fixed block 14
is installed on.

In FIG. 7, in addition to the four bearings 28 that support the flexible gear 24, two bearings 30 are arranged parallel to the shaft 2o, and are attached to the fixed block 14 by the shaft 29. In this way, By adding two more bearings 3o, the flexible gear 24 is prevented from moving slightly in the left-right direction in FIG.

Furthermore, FIG. 8 shows an embodiment showing a method of attaching the shaft 27 holding the bearing 28 to the fixed block 14. In the figure, the bearing 28a is rotatably mounted on the shaft 2, and its movement in the thrust direction is restricted by a right ring 34.

The left end of the shaft 27a forms a flange, and a washer 32. It is fixed to the fixed block 14 with screws 33. Here, an eccentric ring 31 is attached to the outer periphery of the flange portion of the shaft 27a, and by rotating the eccentric ring 31, the shaft 27a is rotated with respect to the fixed block 14.
a can be finely adjusted in the radial direction.

In a similar manner, shaft 29. Therefore, the bearing 30 also
It is also possible to make fine adjustments to the fixed block 14 in the radial direction.

FIG. 9 shows another embodiment of the mechanism for catching the pack rat/coat between the pinion and the flexible gear, and between the shaft and the flexible gear, in which the flexible gear 24 is slightly suppressed and deformed by the pinion 26 and the shaft 20. This eliminates backlash between the two. Further, in order to prevent the flexible center from moving in the left-right direction in the figure, a bearing 30 is fixed to the fixed block 14 via a shaft 29.

Next, the operation of the present invention will be explained. In FIG. 6, the rotation angle of the motor 15 is determined by the rotary encoder 21.
is detected and converted into an electrical signal. By means of this signal, the angular rotational speed of the motor is precisely controlled via a suitable control device. This rotational movement causes the pinion 2
6. Via the flexible gear 24, the shaft 20 is driven linearly. At this time, the bearing 28 causes the flexible/pull gear to move from the pinion 26. Since it is pressed against the shaft 2o, transmission without backlash can be performed, and the rotational angle operation of the motor is accurately transmitted to the shaft 2o. When the motor is driven and the pinion rotates when a large load is applied to the shaft 2o, the flexible gear may move in the left-right direction in Fig. 6. In this case, the bearing 3o in Fig. 7 prevents the movement. It is played. In this way, the axis 2o
When the is driven, the brackets 17 and 18 connected to this
and shaft 19 are driven together.

As can be understood from the above explanation, the drive mechanism of the present invention transmits the rotational motion of the pinion 26 to the shaft 20 via the flexible gear 24. The discrepancy between the shaft 2o and the shaft 2o can be made zero. In other words, when the distance between the two changes due to vibration 1 of the pinion, bending of the shaft 2o, etc., the error is absorbed by the elastic deformation VC of the flexible gear 24, and as a result, the error is absorbed by the tooth surface.
Second,.

There will be no surface pressure or gaps. As a result, the rotational motion of the motor 16 can be accurately transmitted to the shaft 20.

In addition, as shown in FIG.
The flexible gear 2 is provided with several bearings.
By deforming the motor 4 and pressing it against the pinion 26 and the shaft 2o, and by adjusting the position of the shaft 27 using a more eccentric ring shown in FIG. ．． It is possible to easily eliminate backlash while fixing the position of the shaft 2o.

Furthermore, as shown in FIGS. 7 and 9, more accurate transmission can be achieved by preventing the flexible gear from moving in the left-right direction in the drawings by the bearing 3o.

As described above, according to the present invention, with a simple configuration, it is possible to eliminate the discrepancy and achieve high-speed positioning.

[Brief explanation of drawings]

Figure 1 is a plan view of a positioning device using a ball screw.
2 is a side view of the same, FIG. 3 is a front view of a positioning device according to an embodiment of the present invention, FIG. 4 is a side view of the same, FIGS. 5 and 6 are sectional views of essential parts of the device, and FIG. FIG. 7 is a sectional view of the flexible gear, FIG. 8 is a sectional view of the shaft supporting the bearing, and FIG. 9 is a sectional view of another flexible gear. 14...Fixed block, 2o...Curved axis, 24...
...Flexible gear, 26...Pinio/, 28, curve, bearing. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 5 Figure 4A! O Figure 6 Q Figure 7 4 Figure 9 G

Claims (2)

[Claims] (1) A shaft extending in one direction, a fixed block that is slidable in the axial direction of this shaft, and fixed to this fixed professional ivy,
and a rotationally driven pinion; a ring-shaped flexible gear that can mesh with the pinion and the shaft; A positioning device consisting of a bending ring that deforms this flexible gear. (2) The positioning device according to claim 1, wherein two of the bearings are provided in a direction substantially perpendicular to a direction connecting the pinion that contacts the flexible gear and the shaft.