JPH09192985A - Linear servo machine - Google Patents

Abstract

(57) [PROBLEMS] To obtain a processing machine in a linear servo processing machine, which is capable of detecting the position of a movable member with a high detection accuracy and a high rigidity with no limit in the detection stroke. In a linear servo processing machine, a rotary encoder (8) provided on a mounting plate (9) of a mounting base (3) of the processing machine, a pinion (7) rotatably connected to the rotary encoder (8) and a mounting base (3) are provided. The mounting base 3 has a rack 6 which is provided on a linear guide rail 5 which moves relatively and which is screwed into the pinion 7, and which is output based on an output pulse of a rotary encoder 8 which is output according to the rotation of the pinion 7.
The position of the linear guide rail 5 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-scale processing machine using a linear servo motor, for example, a linear servo processing machine such as a laser processing machine or a machining center.

[0002]

2. Description of the Related Art In a linear servo processing machine, a linear servo motor is arranged as a drive source on each movable shaft of the processing machine, and the position of the movable portion is detected by some method using a linear scale or the like, and an NC device or the like is used. Position control is performed by the control device.

As a conventional linear servo processing machine, for example, there is an industrial robot apparatus using a linear motor disclosed in Japanese Patent Laid-Open No. Hei 5-269684. In this, an example of using a linear body (such as a timing belt) and a rotary encoder as a position detecting method of a linear motor is disclosed. Further, Japanese Patent Application Laid-Open No. 2-246705 discloses an example in which a rotary body such as a roller and a pulse encoder interlocked with the rotary body are provided to detect the position and speed of a linear motor. Further, an example is disclosed in which two linear motors are arranged on both sides of the moving body.

FIG. 11 shows an external view of a processing machine using a linear servo motor. Reference numeral 22 is a primary coil of the X-axis linear servo motor, 23 is a Z-axis partial mount fixed to the primary coil 22, and 25 is a rail portion of the X-axis linear guide rail. Reference numeral 21 denotes an X-axis cross beam portion, to which the rail portion 25 of the linear guide rail is attached. Linear guide rail guide block 2
4 is fixed to the Z-axis partial mount 23. Reference numeral 26 is a secondary side magnet portion of the X-axis linear servo motor.
Reference numeral 27 denotes a primary side coil of a Y-axis linear servomotor, which is fixed to lower portions on both sides of the cross beam portion 21. 28 is the rail portion of the Y-axis linear guide rail, 3
Reference numeral 0 is a secondary side magnet portion of the Y-axis linear servo motor. These are on both sides of the cross beam section. Reference numeral 20 denotes a pedestal portion for fixing the rail portion of the guide rail and the secondary magnet portion of the Y-axis linear servomotor.

FIG. 12 is a structural diagram of the cross beam portion 21. The cross beam has a drawing material structure, 17 is a square frame forming the cross beam, and 34 is a reinforcing plate arranged in the horizontal direction in the square frame 17.

Next, the operation of the above linear servo processing machine will be described. A movement command is given to the primary side coils 22 and 27 of the linear servo motor from a control device (not shown). The Z-axis part mount 23 and the part forming the X- and Y-axis parts move along a predetermined movement path. The position is detected by a linear scale or the like installed along the moving path of the position. Alternatively, as in the above-described disclosed example, the position is detected by the linear body stretched along the moving path and the rotary encoder attached to the moving table side. The position detection signal is fed back to the control device to perform position control.

Next, the action of the cross beam will be described. The cross beam supports the weights of the X and Z axes, and also bears the impact load generated during acceleration and deceleration of the Y axis.

[0008]

The conventional linear servo-machining machine as described above uses a linear scale, which limits the manufacturing stroke and cannot be used for a large-scale machine.

Further, the stretched strip and the rotary encoder have a weaker servo rigidity, so that they cannot be used with high speed, high acceleration and high precision in a large-scale processing machine.

Further, the conventional cross-beam drawn-out material structure is weak against shearing force, its eigenvalue is low, and its servo rigidity is low,
There was a problem that resonance could occur during acceleration / deceleration or during movement, making it impossible to operate at high speed and high acceleration.

Further, as shown in FIG. 11, when two linear servo motors are installed under both ends of the cross beam, a magnetic attraction force acts between the primary side coil and the secondary side magnet of the linear servo motor, and the cross beam is generated. There is a problem in that bending stress acts on the core to reduce its rigidity, resulting in resonance during operation, which makes it impossible to operate at high speed with high acceleration and high accuracy.

Further, in the rotating body and the pulse encoder associated therewith as disclosed in JP-A-2-246705, slippage may occur at high speed, and the position of the moving body can be detected with high accuracy. There wasn't.

[0013]

A linear servo processing machine according to the present invention includes a rotary encoder provided on a first member of the processing machine, and a pinion having a rotary shaft rotatably connected to the rotary encoder. An output pulse of the rotary encoder, which is provided on a second member of the processing machine that moves relative to the first member, has a rack screwed to the pinion, and is output according to rotation of the pinion. Based on the above, the relative position between the first member and the second member is detected.

The first member provided with the rotary encoder is a movable member, and the second member provided with the rack is a fixed member.

Further, a ball screw shaft rotatably provided on a fixed member of the processing machine, a ball screw nut screwed on the ball screw shaft provided on the movable member of the processing machine, and rotatable with the ball screw shaft. And a rotary encoder connected to the rotary encoder, and the position of the movable member is detected based on the output pulse of the rotary encoder that is output according to the rotation of the ball screw shaft.

Further, the cross beam having a pull-out member structure in which reinforcing members are provided obliquely from both corners of the cross beam having a square-shaped cross section is provided.

Further, the primary sides of the linear servo motors are provided on both side surfaces of the cross beam, and the secondary sides of the two linear servo motors are provided in the fixed-side mount portion.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 is a side view showing a position detecting method of a processing machine using a linear servo motor according to the first embodiment, and FIG. 2 is a plan view of FIG. In the figure, 1 is a primary side coil portion of the linear servo motor, and 2 is a secondary side magnet portion of the linear servo motor.
A linear servomotor is constituted by 1 and 2, and when a command is given to the primary side coil portion 1 of the linear servomotor from the control device, a linear reciprocating motion is performed along the movement path. Reference numeral 3 is a mounting base as a first member fixed to a primary side coil portion 1 of the linear servo motor and a guide block 4 of a linear guide mounted along the movement path. Reference numeral 5 denotes a rail portion of the linear guide, which is installed on both sides of the linear servo motor along the movement path. The linear guide rail 5 corresponds to the second member. A rack 6 is attached to the outside of the linear guide rail 5 and meshes with the pinion 7. The pinion 7 is attached to the output shaft of the rotary encoder 8, and the mounting base 3
When is moved along the moving path, the pinion 7 engaged with the rack 6 is rotated, the position of the mounting base 3 is accurately detected by the rotary encoder 8, and the feedback is given to the control device.
Reference numeral 9 is a mounting plate for fixing the rotary encoder 8 to the mounting base 3. This device has X, shown in FIGS.
Can be used on either Y axis.

Embodiment 2. 3 is a front view showing a position detecting method of a processing machine using a linear servo motor according to the second embodiment, and FIG. 4 is a plan view of FIG. In the figure, 10 is a screw shaft portion of the ball screw, which is mounted on the outside of the linear guide rail 5 and has bearings 13, 1
4 rotatably supported. Reference numeral 11 denotes a nut portion of the ball screw, which is a fixed block 12 fixed to the mounting base 3.
It is fixed so that it does not rotate. Reference numeral 15 is a coupling that connects the ball screw shaft 10 and the rotary encoder 8, and 16 is a bracket that fixes the rotary encoder 8. When the mounting base 3 makes a linear reciprocating motion along the movement path, the ball screw nut 11 also moves, the ball screw shaft 10 rotates in accordance with the movement, and the rotary encoder 8 also rotates in synchronization with the position of the mounting base 3. Accurate detection without the need for a mechanical backlash adjustment mechanism,
Give feedback to the controller. This device can be used for both the X and Y axes shown in FIGS.

Embodiment 3 FIG. 5 is a structural diagram of a cross beam of a drawn material structure of a processing machine used for the linear servo motor according to the third embodiment. Reference numeral 17 is a square frame forming a cross beam, 18 is a reinforcing plate that is reinforced diagonally from both corners of the square frame 17, and 19 is extended horizontally from the mating portion of the reinforcing plate 18 to the frame side surface. It is a reinforced plate. A lightweight, high-rigidity cross beam is configured by 17, 18, and 19.

Embodiment 4 FIG. FIG. 6 is a structural diagram of a processing machine using the linear servo motor according to the fourth embodiment. Description of the same reference numerals is omitted. 20 is a pedestal part. On the mounting surface protruding from both side surfaces of the pedestal portion 20, the secondary magnet portion 31 of the linear servo motor,
A linear guide rail 28 is attached. Reference numeral 21 denotes the X-axis cross beam described in the third embodiment. A primary side coil portion 27 of a linear servomotor and a linear guide block 29 are attached to both side surfaces of the X-axis cross beam 21. 31 is a laser processing head 3
It is a processing head mounting plate for mounting 2. The processing head mounting plate 31 is adapted to move up and down in the Z-axis direction. FIG.
In the above, a case of a laser processing machine has been described as one of the embodiments, but as another embodiment, a case of a processing machine such as a machining center will be described with reference to FIG. 7.
Description of the same reference numerals is omitted. A machining head portion 33 is composed of a spindle motor of a machining center or the like. The processing head portion moves up and down in the Z-axis direction. Although the machining head is located on the front side of the cross beam in both FIG. 6 and FIG. 7, it is possible to attach the machining head to the opposite side of the cross beam or to both front and rear surfaces of the cross beam. FIG. 8 shows a sectional view of the X-axis cross beam 21. Description of the same reference numerals is omitted.

FIG. 9 shows an eigenvalue analysis according to this embodiment, and FIG. 10 shows an eigenvalue analysis result according to the conventional method. As the boundary condition, both ends of the cross beam were analyzed as free. Also the weight of the cross beam, and Z
A weight of 100 kg was applied to the shaft portion at a position of Y = 240 mm and Z = -60 mm from the center of the cross beam.
As is clear from the analysis results, in a cross beam of similar weight, the primary eigenvalue is 51 Hz in the conventional method.
Whereas that of the present invention is raised to 106 Hz.

[0023]

As is apparent from the above description, the linear servo processing machine of the present invention has the following effects.

By detecting the relative movement of the rack and the pinion with the rotary encoder, the position of the movable member in the linear servo machine can be detected with high servo rigidity and at high speed and with high accuracy.

The first member provided with the rotary encoder is used as the movable member, and the second member provided with the rack is provided.
By using the above member as the fixed side member, the rack, which requires a space in the longitudinal direction, is fixed without moving, and space saving can be achieved.

Further, since the position of the movable portion of the linear servo motor is constituted by a ball screw and detected by a rotary encoder, servo rigidity is high and high-speed and high-accuracy position detection is possible.

Further, in a large-scale processing machine driven by a linear servomotor, a cross beam having a square-shaped drawing material structure and an oblique reinforcing member is provided so that a cross beam having a strong shearing force, a high rigidity and a light weight can be obtained. With possible
This enables highly accurate position detection without resonance.

Further, since two linear servo motors are arranged on both side surfaces of the cross beam, the magnetic attraction force generated in the linear servo motor acts on the cross beam not by bending stress but by tensile stress. The cross beam, which is a movable portion, has a high rigidity, and it is possible to prevent resonance during movement. Further, the structure of the Z-axis portion can be easily attached to the front surface and the rear surface or both surfaces of the cross beam.
Furthermore, the cross beam itself is lightweight, enabling highly accurate position detection without resonance.

[Brief description of the drawings]

FIG. 1 is a side view showing a position detecting method for a linear servo processing machine according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a position detecting method for the linear servo processing machine according to the first embodiment of the present invention.

FIG. 3 is a front view showing a position detecting method for a linear servo processing machine according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a position detecting method for a linear servo processing machine according to a second embodiment of the present invention.

FIG. 5 is a structural diagram showing a cross beam structure of a linear servo processing machine according to a third embodiment of the present invention.

FIG. 6 is a structural diagram showing a structure of a linear servo processing machine according to a fourth embodiment of the present invention.

FIG. 7 is a structural diagram showing a structure of a linear servo processing machine according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a cross beam according to a fourth embodiment of the present invention.

FIG. 9 is a structural analysis result of a cross beam according to the present invention.

FIG. 10 is a result of a conventional structural analysis of a cross beam.

FIG. 11 is a structural diagram showing a structure of a conventional linear servo processing machine.

FIG. 12 is a structural diagram showing a cross beam structure of a conventional linear servo processing machine.

[Explanation of symbols]

1 Primary servo coil part of linear servo motor 2 Secondary magnet part of linear servo motor 3 Mounting base 4 Linear guide block 5 Linear guide rail 6 Rack 7 Pinion 8 Rotary encoder 9 Mounting plate 10 Ball screw screw shaft 11 Ball screw nut part 12 fixed block 13,14 bearing part 15 coupling 16 bracket 17 square frame 18,19 reinforcing plate 20 frame part 21 X-axis cross beam part 22 X-axis linear servo motor primary side coil part 23 Z-axis part Mounting base 24 X-axis linear guide block 25 X-axis linear guide rail 26 Secondary magnet part of X-axis linear servo motor 27 Primary coil part of Y-axis linear servo motor 28 Y-axis linear guide rail 29 Y Linear guide for shaft Lock 30 Y-axis linear servo motor secondary magnet unit 31 processing head mounting plate 32 processing head portion 34 a reinforcing plate such as a laser for machining head 33 machining center

Claims (5)

[Claims] 1. A rotary encoder provided on a first member of a processing machine, a pinion having a rotary shaft rotatably connected to the rotary encoder, and a processing machine of the processing machine that moves relative to the first member. The first member and the second member are provided on a second member and have a rack screwed into the pinion, and based on an output pulse of the rotary encoder that is output according to the rotation of the pinion. A linear servo processing machine characterized by performing relative position detection. 2. A first unit provided with a rotary encoder
The linear servo processing machine according to claim 1, wherein the member is a movable member, and the second member provided with the rack is a fixed member. 3. A ball screw shaft rotatably provided on a fixed side member of the processing machine, and a ball screw nut provided on a movable side member of the processing machine and screwed with the ball screw shaft.
A rotary encoder rotatably connected to the ball screw shaft is provided, and the position of the movable member is detected based on an output pulse of the rotary encoder output according to the rotation of the ball screw shaft. And linear servo processing machine. 4. A linear servo processing machine comprising a cross beam having a pull-out material structure in which reinforcing members are provided obliquely from both corners of the cross beam having a square cross section. 5. The primary side of the linear servo motor is provided on both side surfaces of the cross beam, and two of the two linear servo motors are provided.
A linear servo processing machine characterized in that the secondary side is provided on the fixed side pedestal part.