JPS5874226A - Positioning method - Google Patents

Abstract

PURPOSE:To execute positioning at a high speed and also with high accuracy, by using driving of a motor and a ball screw and driving by a linear motor at the same time, and sharing accelerating force and decelerating force required when moving a positioning unit, with this linear motor. CONSTITUTION:A motor 18 is rotated, and by rotation of a ball screw 21, a moving unit 23 is guided by a guide 24 and is moved in the direction X, and also, accelerating force is provided to the moving unit 23 by energizing a stator 26 of a linear motor. When it has reached a decelerating position, the number of revolutions of the motor 18 is decreased, also the stator 26 is energized in the opposite direction, and to the moving unit 23, force is applied backward against its advancing direction, and it is decelerated. When its speed has become a prescribed value or below, energizing of the stator 26 is stopped, and positioning is executed by rotation of the ball screw 21. Movement and positioning in the direction of an axis Y are executed in the same way by moving a positioning unit 34 by a motor 28, a ball screw 29, a stator 31, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-speed and highly accurate positioning method using a linear motor. FIG. 1 shows an example of a turret punch press to which the present invention is applied. The X-Y table 1 is driven vertically and horizontally by numerical control to move the sheet metal 2 clamped on the X-Y table 1. Meanwhile, the turret 3 rotates to select the bunch 4 to be processed. When the sheet metal 2 is moved to the position where it is to be processed, the selected punch 4 is lowered to perform punching or the like. Figure 2 shows the conventionally used
FIG. 3 is an explanatory diagram of the structure of a Y table. When the motor 5 rotates, the ball screw 8 rotates through the gears 6 and 7.

A pole screw nut 10 is fixed to the moving unit 9, which is given a propulsion force in the X direction, and is guided by a linear guide 11 to move. In addition, the moving unit 9 has a motor 12.
is mounted, and when the motor 12 rotates, the connected ball screw 13 rotates. Pole screw nut 14
The positioning unit 15 to which is fixed is the pole screw 1
With this configuration, the positioning unit 15 with the chuck 17 that holds the sheet metal moves in the Y direction on the moving unit 9 guided by the linear guide 16 according to 30 rotations, and the positioning unit 15 with the chuck 17 that holds the sheet metal rotates the motor 5' and the motor 1'2. X by numerical control.

0 positioned at an arbitrary position in Y In the above-mentioned conventional technology, it is relatively easy to perform precise positioning using a ball screw, but if the moving unit is to be moved at high speed, a large acceleration is required. Therefore, a low inertia servo motor with a large torque-to-inertia ratio is generally used as a drive motor. However, even if the currently developed motors have a low inertia, the torque-to-inertia ratio T (Kg-cm)/J ( Kg-i) is about 1, and even if we assume that the inertia of the ball screw is 0, the angular acceleration is about 980 rad/s22.

In reality, in addition to the inertia of the ball screw, the mass of the moving unit acts as a load on the motor, and the achievable angular velocity is at most small.

A hydraulic servo motor is a driving source with a much larger torque-to-inertia ratio, but it requires a hydraulic power source and has disadvantages such as the high cost of hydraulic servo valves.

Alternatively, instead of using a ball screw or the like, a method of driving the linear motor by mounting the rotor or stator of the linear motor on a moving unit or a positioning unit and setting the stator or rotor at opposing positions can also be considered. Linear pulse motors are used to improve positioning accuracy, but they have the disadvantage of being difficult to obtain large thrust and slow positioning speed. Furthermore, a linear induction motor with a large thrust has the disadvantage that it is difficult to control positioning with high precision.

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a positioning method that has high acceleration characteristics and is highly accurate.

In order to achieve the above object, the present invention uses a linear motor to drive the motor and the ball screw in combination, and shares the additional force and deceleration force required when moving the positioning unit with the linear motor. The load applied to the rotor is limited to the inertia of the rotor itself and the inertia of the ball screw.

Figure 6 shows the present invention. One example is X-Y Chi・□.

Shows the structure of the pull. In FIG. 3, motor 18 is connected to gear 19. It is connected to a ball screw 21 via a gear 20. The pole screw nut 22 is fixed to the moving unit 23, and when the ball screw 21 rotates, the moving unit 25
is guided by the guide 24 and moves in the X direction. Further, a stator 26 of the near motor is fixed to the base 25, and a rotor 27 of the near motor is mounted to the moving unit 26 and positioned opposite to the stator 26 of the near motor. Therefore, stator 2
When 6 is excited, driving force is applied to the moving unit 26 in the X direction.

A ball screw 29 is connected to the motor 2B mounted on the moving unit 26. A ball screw nut 65 is fixed to the positioning unit 34, and when the ball screw 29 rotates, the positioning unit 34 is guided by the guide 30 and moves in the Y direction. The stator 31 of the linear motor is mounted on the moving unit 34, and the rotor 32 of the linear motor is mounted on the moving unit 260 facing it.
is installed. Therefore, when the stator 31 is excited, the positioning unit 54 is given a driving force in the Y direction.

In this arrangement, when moving the moving unit 23 in the X-axis direction and positioning it, the motor 1B is rotated, and the stator 26 of the linear motor is excited to apply acceleration force to the moving unit 23. When the moving unit 26 moves to the position where it should be decelerated, the rotational speed of the motor 18 is reduced, and the stator 26 of the linear motor is excited in the opposite direction to apply force to the moving unit 26 in the opposite direction to the direction of movement. is added to reduce the speed. When the speed falls below a predetermined value, the excitation of the stator 26 is stopped and positioning is performed in the OYX axis direction by rotation of the ball screw 21. In this case, the energy required to move the unit is
FIG. 6 shows the division of labor between the linear motor and the ball screw rotation motor. In FIG. 6, the shaded area is the energy shared by the linear motor, and the dotted area is the energy shared by the ball screw rotation motor.

As described above, according to the present invention, the load applied to the rotary motor can be significantly reduced, and as a result, it is possible to rotate the rotary motor with high angular acceleration, and high-speed positioning can be performed. Furthermore, since positioning itself is performed using a ball screw,
It is possible to maintain high positioning accuracy as before. Furthermore, compared to positioning using only a linear pulse motor, control is simpler and high-speed, high-precision positioning can be achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of an application example of the present invention in which sheet metal is processed with a turret punch press, Figure 2 is a configuration diagram of an X-Y table using a conventional positioning method, and Figure 3 is An explanatory diagram of the X-Y table to which the present invention is applied, FIG. 4 is a sectional view taken along the line 1-1 in FIG. 6, FIG. 5 is a sectional view taken along the if-If line in FIG. 3, and FIG. FIG. 1B...Morta 21...Pole screw 22...
Ball screw nut 26... Stator 27... Rotor 28... Motor 29... Pole screw 33.
... Ball Nejina Figure 4 Day 5 67

Claims (1)

[Claims] The stator or rotor of a linear motor is mounted on the positioning unit, the rotor or stator is installed on a fixed part facing the stator or rotor, and the driving of the linear motor provides acceleration and deceleration force for movement to the positioning unit. At the same time, a positioning method in which the propulsive force generated by the relative rotational movement of the screw and nut by the rotary motor acts on the positioning unit, thereby controlling the linear motor and the rotary motor.