JPS5945514A - Positioning device - Google Patents

Abstract

PURPOSE:To attain speedy and highly accurate positioning, by using a rotary motor and linear motors. CONSTITUTION:A command pulse corresponding to a distance to be moved and its speed is applied to a position controller. When receiving the command, a DC motor 6 is turned and a moving unit 10 is moved in the direction of the X axis. The revolution speed and the revolution variable detected from the shaft of the DC motor 6 are fed back. The command also actuates linear motors 19, 20 to move the moving unit 10. The rotary motor 6 changes its torque at the leading and trailing edges. At that time, the movement of the moving unit 10 is charged by the linear motors 19, 20. The final position of the positioning is determined by the rotation of a ball spring 9 driven by the DC motor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a high-speed and highly accurate positioning device using a linear motor.

[Prior art]

FIG. 1 is a perspective view schematically showing an example of a saucer/Z-chip press to which the present invention is applied. In the figure, an X-Y table 1 is driven vertically and horizontally by numerical control to move, for example, a sheet metal 2 clamped onto the X-Y f-pull 1. On the other hand, the turret 3 rotates to select the nozzle 4 to be machined. 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. FIG. 2 is a top view illustrating the configuration of an X-Y table using a conventional positioning device. In Figure 2, the base 5
When the upper rotary motor 6 rotates, the pole screw 9 rotates via the gears 7 and 8. On the other hand, a pole screw nut 11 is fixed to the moving unit 10, and the moving unit 10 is given a propulsion force in the X-axis direction (indicated by a dotted line in the figure) according to the rotation of the pole screw 9, and It is guided by a guide 12 and moves in the X-axis direction. Furthermore, a rotary motor 13 is mounted on the moving unit 10, and when the rotary motor 13 rotates, a pole screw 14 connected thereto rotates. On the other hand, the positioning unit 16 to which the pole screw nut 15 is fixed is guided by the linear guide 17 on the moving unit 10 as the pole screw 14 rotates, and moves on the moving unit 10 in the Y-axis direction (indicated by a dotted line in the figure). Move to. According to such a configuration, sheet metal 2 (
The positioning unit 16, which has a chuck 18 that holds the rotary motor 6 and the rotary motor 13 (Fig. 1), can be positioned at any position on the X and Y coordinates by numerically controlling the rotation of the rotary motor 6 and the rotary motor 13 by a control device (not shown). be done.

In the above-mentioned conventional technology, it is relatively easy to perform precise positioning using the pole screw 9 driven by the rotary motor 6, but a large acceleration is required if the moving unit 10 is to be moved at high speed. . A low inertia servo motor with a large torque-to-inertia ratio is generally used as the rotary motor 6 that drives the rotary motor 6. However, even if the rotary motors currently being developed have low inertia, the torque-to-inertia ratio T ('Kf-t:m) / , T (Kg
-J") is about Id1, and even if we assume that the inertia of the pole screw 9 is 0, the obtained angular acceleration is 980ra.
It is about d/θ2. In reality, in addition to the inertia of the pole screw 9, the mass of the moving unit 10 becomes a load on the rotary motor 6, so that the achievable angular acceleration is smaller and high-speed positioning becomes difficult. The same can be said of the pole screw 14 and the rotary motor 13.

A hydraulic servomotor is a driving source with a much larger torque-to-inertia ratio, but its use requires a hydraulic power source, and the hydraulic servo valve is expensive.

Furthermore, the rotor or stator of the linear motor is mounted on a moving unit or a positioning unit without using a rotating motor for driving, a pole screw, etc., and the stator or rotor of the linear motor is installed at a position facing the rotor or stator. Depending on the situation, a method of driving a moving unit or a positioning unit may also be considered. Linear pulse smoke can be used to increase positioning accuracy, but it has the disadvantage that the positioning speed becomes slow when a large thrust is obtained. Furthermore, when a linear induction motor with a large thrust is used, there is a drawback that it is difficult to control positioning with high precision.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a positioning device with high acceleration characteristics and high accuracy.

[Summary of the invention]

The present invention combines the drive by a linear motor with the drive by a rotary-linear motion conversion system consisting of a rotary motor and a pole screw, a nut, etc. connected to the rotary motor, and uses the accelerating force and deceleration force required when moving the positioning unit. By having the linear motor take over the load, high-speed and highly accurate positioning is possible.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 5, FIG. 4, and FIG. FIG. 3 is a top view showing an embodiment of the X-Y table to which the positioning device according to the present invention is applied;
The figure and Figure 5 are the I-I line sectional view of Figure 3 and ■-■ respectively.
In the line partial sectional view, the same reference numerals in the drawings indicate the same or similar parts. In Figure 3, Figure 4, and Figure 5, the base 5
A rotary motor 6 provided in the rotary motor 6 is connected to a pole screw 9 via gears 7 and 8. On the other hand, the pole screw nut 1
1 is fixed to the moving unit 10, and the pole screw 9
When rotates, the moving unit 10 is guided by a linear guide 12 provided on the base 5 and moves in the X-axis direction (indicated by a dotted line in the figure). Further, a stator 19 of a linear motor is fixed to the base 5, and a rotor 20 of a linear motor attached to the moving unit 10 is positioned opposite to this. Therefore, when the stator 19 of the linear motor is excited, a driving force is applied to the moving unit 10 in the X-axis direction.

Further, a ball screw 14 is connected to a rotary motor 13 mounted on the moving unit 10. On the other hand, the ball screw nut 15 is fixed to a positioning unit 16, and when the ball screw 14 rotates, the positioning unit 16 is guided by a linear guide 17 provided on the positioning unit 16 in the Y-axis direction (indicated by a dotted line in the figure). ). Furthermore, the positioning unit 16 includes a stator 21 of the linear motor.
is mounted, and a rotor 22 of the same linear motor is fixedly attached to the portion of the moving unit 10 that faces this. Therefore, when the stator 21 of the linear motor is excited, a driving force is applied to the positioning unit 16 in the Y-axis direction.

With this configuration, the positioning unit 16 having the chuck 18 that holds the sheet metal 2 (FIG. 1) controls the rotary motor 6 and the stator 19 of the linear motor, and the rotary motor 15 and the stator 21 of the linear motor to It is positioned at an arbitrary position on the Y coordinate.

In the embodiment according to the present invention described above, drive by a linear motor is used in combination with drive by a rotary motor, a ball screw, etc., and the acceleration force and deceleration force necessary when moving the positioning unit are shared by the linear motor. , the load on the ball screw and therefore the rotary motor can be reduced, and high-speed and highly accurate positioning can be achieved. In this case, if the load on the ball screw is reduced, the required diameter of the capole screw can be reduced in terms of strength, and as a result, the load on the rotary motor can be further reduced.

In the above embodiment, linear motors are used to drive both the moving unit and the positioning unit in both the X-axis direction and the Y-axis direction, but a corresponding effect can be obtained even if a linear motor is used in only one of them. Furthermore, the above embodiment applies the present invention to the positioning of a two-dimensional X-Y table, and can be applied not only to a turret punch press (Fig. 1) but also to a wide range of machine tools, assembly machines, etc. Note that the present invention is similarly applicable to one-dimensional, three-dimensional, etc. positioning. Therefore, the names of the moving unit and positioning unit in this embodiment are generally represented by the name of the positioning unit. In the above embodiment, the rotational-linear motion conversion system connected to the rotary motor is composed of a ball screw and a nut, but it may be composed of a rack and a pinion.

Next, FIG. 6 shows a control block diagram of an example of a control device for controlling the above rotary motor and linear motor according to the present invention. , in the figure, a pulse train of a number and interval corresponding to the amount and speed to be moved by the command pulse is input to the position controller 23.

This input signal is converted into an analog voltage by the position controller 23, and the speed controller 24 and the Do motor driver 25.
Then, the DC motor 26 is driven to move the load 27.

Here, the DC motor 26 corresponds to the rotary motor 6 or the rotary motor 13 (FIG. 3), and the load 27 corresponds to the moving unit 10.
Alternatively, the motor load corresponding to the positioning unit 16 (FIG. 3) is shown. A tacho generator 28 and an encoder 29 are directly connected to the shaft of the DC motor 26, and detect the rotational speed of the motor shaft and the moving speed and amount of rotation of the load 27, respectively. These detected quantities are fed back to the inlet portions of the speed controller 24 and position controller 23, respectively. Furthermore, the output voltage e of the speed controller 24 is inputted to the phase controller 30, and the output current 1 of this phase controller 30
is given as an exciting current to the stator of the linear induction motor 31, and the linear induction motor 31 controlled by this moves the load 27 together with the Do motor 26.

In such a configuration, the load 27, for example the mobile unit 1
0 (Fig. 3) in the X-axis direction, when a pulse train of a number and interval corresponding to the movement amount and movement speed is applied to the input of the position controller 23 as a command pulse, the speed controller 23 The output voltage θ of 24 changes as illustrated in FIG. This output voltage e has an acceleration portion and a deceleration portion as shown. At this time, the torque of the DC motor 26, for example the rotary motor 6, changes in proportion to this output voltage e.

Furthermore, the thrust of the linear induction motor 3, for example, the stator 19 and rotor 20 (FIG. 3) of the linear motor, depends on the characteristics of the phase controller 30 that controls it. Changes in proportion to output current 1. Next, when the load 27, for example, the positioning unit 16 (FIG. 3) is moved and positioned in the Y-axis direction, the same procedure is performed.

According to the control device of this embodiment, high-speed and highly accurate positioning control is possible by giving the amount and speed of movement as command pulses to control the rotary motor and linear motor.

Next, in this embodiment, the load 2
7. For example, just before the moving unit 10 (FIG. 3) reaches the final predetermined position in the The thrust of the linear motor may be controlled to be zero. In this way, for example, the final part of positioning of the moving unit 10 is performed only by the rotation of the ball screw 9 (FIG. 3) driven by the DC motor 26, for example, the rotary motor 6 (FIG. 3). High positioning accuracy can be easily obtained. The same applies to positioning control in the Y-axis direction of the positioning unit 16 (FIG. 3).

Furthermore, in this embodiment, the characteristic of the phase controller 300 that controls the linear induction motor 31 is such that when the input voltage e is between 81 and θ2 as illustrated in FIG. In this way, when moving the load 27, for example, the moving cornice 10 (FIG. 3) in the X-axis direction and positioning it, the position controller 25 receives a command pulse. When a pulse train corresponding to the movement and movement speed is applied with l-, the output voltage θ of the speed controller 24 changes as illustrated in FIG. 9 as well as FIG. 7, and the DC motor 26
For example, the torque of the rotary motor 6 changes in proportion to the output voltage θ, but the stator of the linear induction motor 31, for example, the phase controller 30 that drives the stator 19 of the linear motor has a dead zone as illustrated in FIG. Therefore, the excitation current 1 of the stator 19 of the linear motor 31, for example, changes as shown in FIG. It changes in proportion to the current 1 as illustrated in FIG. The near motor is driven only in the moving parts where the acceleration force and deceleration force are most needed. Further, in the final part of positioning, the value of the output voltage e of the speed controller 24 becomes small, so that the excitation current 1 of the stator 19 of the near motor becomes 0, and therefore, the excitation current 1 of the stator 19 of the near motor becomes 0. Positioning is done only by rotation. At this time, the energy necessary for moving the moving unit 10 is transferred to the linear induction motor 3, for example, to the stator 1.
FIG. 10 shows how the linear motor 9 and the DC motor 26, such as the rotary motor 6 for driving the ball screw 9, are separated. In this way, the linear motor can be distributed to the parts where acceleration and deceleration forces are most needed for movement, and
Since the final part of positioning is performed only by the rotation of the ball screw driven by the rotary motor, high-speed and highly accurate positioning can be easily and effectively performed. The same applies when positioning the load 27, for example, the positioning unit 16 (FIG. 3), by moving it in the Y-axis direction.

〔Effect of the invention〕

As described above, according to the present invention, by using a linear motor in combination, the load on the rotary motor can be significantly reduced, making it possible to rotate with high angular acceleration and perform high-speed positioning. Driven by a rotating motor
It has its own high positioning accuracy due to the rotation-linear motion conversion system of ball screws, etc., and it is easier to control and allows for high-speed, high-precision positioning compared to positioning with a single linear nozzle motor. Therefore, it can be widely used as a positioning device for machine tools, assembly machines, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a turret punch press as an example to which the present invention is applied, FIG. 2 is a top view illustrating an X-Y table using a conventional positioning device, and FIG. 3 is a positioning device according to the present invention. 4 is a sectional view taken along line II in FIG. 3, FIG. 5 is a sectional view taken along line n-■ in FIG. 3, and FIG. A control block diagram showing an embodiment of a control device for a positioning device according to the present invention,
7 is an explanatory diagram illustrating the output voltage e of the speed controller 24 in FIG. 6 during movement positioning, FIG. 8 is a characteristic diagram when the phase controller 30 in FIG. 6 is provided with a dead zone, FIG. 9 is an explanatory diagram illustrating the excitation current 1 and thrust of the linear induction motor 31 shown in FIG. 6 when the characteristics shown in FIG. 8 are provided, and FIG.
．． ! : is an explanatory diagram illustrating the state of energy sharing of the DO motor 26. 6...Rotating motor, 9...Ball screw, 10...
Moving unit, 11...Ball screw nut, 14...
・Ball screw, 15...Ball screw nut, 16...
- Positioning unit, 19... Stator of the linear motor, 20... Rotor of the linear motor, 21... Stator of the linear motor, 22... Rotor of the linear motor, 23... Position controller, 24...speed controller,
25...DC driver, 26...DC motor, 27
...Load, 2B...Tacho generator, 29...Encoder, 30...Phase controller, 31...Linear induction motor. Agent Patent Attorney Tadashi Akiki Figure 3 Figure 4 Figure 9 Figure 5 Figure 7 Figure 8 Izuku/Hiki Figure 9

Claims (1)

[Claims] 1. A rotary motor is provided between the positioning unit and the fixed part via a rotation-linear motion conversion system, and the positioning unit is driven by the rotation motor via the rotation-linear motion conversion system. At the same time, the stator (or rotor) of the linear motor is mounted on the positioning unit, and the rotor (or stator) of the linear motor is mounted on the fixed part facing the stator (or rotor).
The linear motor is driven to apply accelerating and decelerating forces to move the positioning unit, and a control device that controls the rotary motor and the linear motor moves the positioning unit to a predetermined position and performs positioning. In addition, the positioning device is configured to stop driving the linear motor just before the positioning unit reaches the predetermined position, and then perform the final portion only by driving the rotary motor. 2. The drive of the linear motor is stopped at a portion where the accelerating force and deceleration force for moving the unit is below a predetermined value, and the portion below this predetermined value is driven only by the rotary motor. A positioning device according to claim 1, characterized in that: