JP2506759Y2 - Machine origin detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to a target object that linearly moves on the shaft by rotation of a shaft having a feed screw of a predetermined pitch in a target object feeding device driven by a motor or the like. The present invention relates to a mechanical origin detecting device of a positioning device that determines a stop position of a workpiece.

[Conventional technology]

In order to stop the work that moves linearly on the shaft of the target object feeding device at a predetermined position, set the origin,
It is necessary to detect this origin. FIG. 6 shows a conventional device of this origin detecting device.

In FIG. 6, reference numeral 1 denotes a work feeding device, which is supported by a bearing (not shown), and the work 6 is rotated in the normal direction / reverse direction by forward / reverse rotation of a shaft 5 having a feed screw of a predetermined pitch. Move linearly in the direction. Reference numeral 2 is a microcomputer that constitutes speed command means and origin detection means, which will be described later, and 3 is arranged close to the moving position of the work 6, and when the work 6 comes into contact with it, from low level (hereinafter simply referred to as “L”) to high level. (Hereinafter simply referred to as "H") limit switch (hereinafter simply referred to as switch) that outputs an origin signal LS that is inverted to 4 has a microcomputer 2 and an encoder 10.
Microcomputer 2 has origin signal LS from switch 3, encoder 1
Origin detection means for detecting the mechanical origin based on the marker signal ΦZ from 0, 7 is a motor which is connected to the shaft 5 via a coupling 8 and rotates in response to a speed command from the microcomputer 2, 10 is a motor 7 Directly connected to the motor 10 1
An encoder that reverses to "H" once per rotation and feeds back a marker signal ΦZ having a frequency proportional to the rotation of the motor 10 to the microcomputer 2, 11 and 12 are respectively the work feeding device 1
Limit switches for detecting the limit position for preventing the work 6 from colliding with the bearing and being damaged.

The operation of this mechanical origin detecting device will be described with reference to the time chart shown in FIG. 7 and the flowchart shown in FIG. In addition, S1 in the flowchart of FIG.
~ S6 shows the steps of each operation.

First, the motor 7 is rotated at a high speed V _H by homing command the microcomputer 2 is started (S1), to move the workpiece 6. When the workpiece 6 eventually contacts the switch 3, the origin signal LS is inverted to "H" (S2), and the motor 7 is switched to the low speed V _L (S3). In this way, the workpiece 6 passes through the switch 3 and the origin signal LS is inverted from "H" to "L" (S4),
At the time t _{1 when the} first marker signal ΦZ falls, the microcomputer 2
Stops the return command (S5). As a result, the motor 7 stops, but the work 6 shifts and stops until time t ₂ due to inertia. At this time, the origin shift amount from time t ₁ to time t ₂ corresponds to the shaded area, and the position at time t ₂ is the mechanical origin.

[Problems to be solved by the device]

In the above-mentioned conventional apparatus, the work 6 is the switch 3
Origin signal LS becomes “H” and the origin signal LS
Is inverted to "L", the mechanical origin is the position moved by the origin shift amount from the trailing edge of the first appearing marker signal ΦZ. Therefore, as shown in FIG. If it is in the middle, the machine origin can be detected by the above-mentioned operation, but the work 6 is switched to the switch 3
If it is between the switch 12 and the switch 12, the work 6 must be moved between the switch 3 and the switch 11 by some means, and then the mechanical origin must be detected. In other words, there is a problem that the mechanical origin can be detected only from one direction (for example, the normal rotation direction).

Therefore, an object of the present invention is to provide a machine origin detecting apparatus which eliminates the above-mentioned drawbacks of the conventional apparatus and enables the machine origin to be accurately detected from both the forward rotation direction and the reverse rotation direction.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides a target object feeding device that linearly moves a target object by rotating a shaft having a feed screw of a predetermined pitch, speed command means for rotating a motor connected to the shaft, and It is arranged close to the moving position of the target object, and when the target object comes into contact with it, it is inverted from low level to high level, and when the target object is separated, it outputs an origin signal that is inverted from high level to low level. A limit switch and an encoder that outputs a marker signal that inverts to a high level once per rotation of the motor are provided, and the target object is present on a predetermined side with respect to the limit switch, and the motor is rotated in the forward direction. When rotating and moving the target object in one direction, the origin signal from the limit switch changes from high level to low level. The motor signal is stopped by the first marker signal that appears after the motor is turned, and the target object moves from the position where the motor is stopped due to inertia and stops (the target object moves from the position where this motor stops due to inertia). In the mechanical origin detecting device having origin detecting means for detecting the amount up to the stopped position as an origin shift amount), the encoder outputs an A phase pulse and a B phase pulse in addition to the marker signal. And a waveform shaping circuit that outputs a high-level normal rotation signal and a low-level reverse rotation signal based on the A-phase pulse and the B-phase pulse from the encoder, and the normal rotation signal of the waveform shaping circuit during normal rotation. And the marker signal, and at the time of the reverse rotation, the reverse rotation signal of the waveform shaping circuit and the signal obtained by inverting the marker signal are taken during the forward rotation. And a signal switching circuit for switching the marker signal between the forward rotation signal and the reverse rotation signal at the time of reverse rotation, the origin detection means, in addition to the means for detecting the mechanical origin at the time of forward rotation, the inverted marker signal falls at the time of reverse rotation. The origin shift amount is set as the current position each time, the motor is stopped when the origin signal from the limit switch reverses from low level to high level, and the target object moves due to inertia after stopping the motor from the existing position. It is characterized by further comprising means for detecting the mechanical origin by rotating the motor in the forward direction by an amount corresponding to the addition of the origin shift amount to the movement amount to the stop position.

In the present invention, the mechanical origin is detected by the origin detecting means in the normal rotation by the marker signal in the normal rotation output from the waveform shaping circuit and the signal switching circuit. During reverse rotation, the waveform shaping circuit and signal switching circuit output the marker signal during reverse rotation (the signal that is the inverted marker signal during normal rotation) to detect the trailing edge of the marker signal at the same timing as during normal rotation and shift the position. Is lost.
Then, each time the inverted marker signal falls, set the origin shift amount that the target object moves after stopping the motor during forward rotation as the current position, and change the origin signal from the limit switch from low level to high level. When the motor is stopped when it is reversed, the motor is normally rotated by an amount obtained by adding the origin shift amount to the movement amount from the motor stop to the position where the target object moves due to inertia, and becomes the mechanical origin.

[Embodiment of Device]

An embodiment of the present invention will be described with reference to FIG. 1. A target object feeding device 1 for linearly moving a target object 6 by rotating a shaft 5 having a feed screw with a predetermined pitch.
And a speed command means constituted by a microcomputer 2 for rotating a motor 7 connected to the shaft 5, and the speed command means is arranged close to the moving position of the target object 6 and the target object 6 comes into contact with the low speed command means. A marker that inverts from a level to a high level and outputs an origin signal LS that inverts from a high level to a low level when the target object 6 separates and a high level once per revolution of the motor 7. Encoder that outputs signal ΦZ
10 has the target object 6 on one side with respect to the limit switch 3 (for example, between the switch 3 and the switch 11)
When the target object 6 is moved in one direction by rotating the motor 7 in the normal direction, the origin signal LS from the limit switch 3 first appears after being inverted from high level to low level. The motor 7 is stopped by the marker signal ΦZ, and the target object 6 moves from the position where the motor 7 is stopped due to inertia and stops (the target object 6 moves from the position where the motor 7 stops due to inertia and stops). A mechanical origin detecting device having an origin detecting means configured by a microcomputer 2 for detecting a quantity up to a position as an origin shift amount) as a mechanical origin, wherein the encoder 10 includes an A phase pulse in addition to the marker signal ΦZ. ΦA and B phase pulse Φ
A waveform shaping circuit 13 configured to output B, which outputs a high-level normal rotation signal ΦR and a low-level reverse rotation signal ΦR based on the A-phase pulse ΦA and the B-phase pulse ΦB from the encoder 10, At the time of turning, the logic of the normal signal ΦR of the waveform shaping circuit 13 and the marker signal ΦZ is taken by the AND gate 17, and at the time of reverse, the reverse signal ΦR of the waveform shaping circuit 13 and the marker signal ΦZ are inverted by the inverter 16. A signal switching circuit 14 is provided for switching the marker signal ΦZ by the forward rotation signal ΦR and the reverse rotation signal ΦR at the time of forward rotation and reverse rotation so that the AND gate 18 takes the logic. In addition to the means for detecting, at the time of reverse rotation, the origin shift amount is set as the current position each time the inverted marker signal ΦZ falls, and the origin signal LS from the limit switch 3 is at a low level. From the current position to the position where the target object 6 moves due to inertia and then stops, the motor 7 is stopped and the origin shift amount is added. It is provided with a detecting means constituted by the microcomputer 2 which detects the mechanical origin by rotating the motor 7 in the forward direction.

〔Example〕

1 to 5 show an embodiment of a mechanical origin detecting device according to the present invention. In FIG. 1, the same parts as those of the conventional device shown in FIG. To do.

In FIG. 1, the origin detecting means 4 includes a waveform shaping circuit 13, a signal switching circuit 14 in addition to the microcomputer 2 and the encoder 10.
It has. The encoder 10 generates the marker signal ΦZ which is inverted to “H” once per one rotation of the motor 7, and further generates the A phase pulse ΦA and the B phase pulse ΦB. The quantity pulses .PHI.A and .PHI.B are input to the waveform shaping circuit 13 and shaped into a normal / reverse rotation signal .PHI.R. The signal switching circuit 14 includes two inverters 15 and 16 and two AND gates 17 and 18.
And OR gate 19, and the output of waveform shaping circuit 13 is AND
AN via one input of gate 17 and inverter 15
The marker signal ΦZ is connected to one input terminal of the D gate 18, and the other input terminal of the AND gate 17 and the inverter 16
Is connected to the other input terminal of the AND gate 18 via. The outputs of the AND gates 17 and 18 are connected to the input ends of the OR gate 19, and the output of the OR gate 19 is connected to the microcomputer 2.

Forward / reverse rotation signal Φ output from the waveform shaping circuit 13
Since R becomes "H" at the time of forward rotation and "L" at the time of reverse rotation, the AND gate 17 is in a conductive state at the time of forward rotation, and the AND gate 17 at the time of reverse rotation.
18 becomes conductive. Therefore, during normal rotation, the detection signal ΦO corresponding to the marker signal ΦZ is input to the microcomputer 2 through the AND gate 17 and OR gate 19, and during reverse rotation, detection is performed by inverting the marker signal ΦZ through the AND gate 18 and OR gate 19. The signal ΦO is input to the microcomputer 2. The detection signal .PHI.O will be described with reference to FIG. 2. In FIG. 2, assuming that the time lapse of the origin signal LS of the switch 3 advances from the left to the right in the drawing in the normal direction, the signal switching circuit 14 operates in the normal direction.
The detection signal .PHI.O output from the signal corresponds to the marker signal .PHI.Z as shown by .PHI.0 _1. At the time of reverse rotation, the detection signal .PHI.O output from the signal switching circuit 14 is a signal obtained by inverting the marker signal .PHI.Z as shown by .PHI.0 _2. Becomes As is clear from FIG. 2, the detection signal Φ 0 ₁ at the time of forward rotation and the detection signal Φ 0 ₂ at the time of reverse rotation have the same falling time points, and the marker signal ΦZ is used for both the forward rotation direction and the reverse rotation direction. Does not cause misalignment.

Next, the operation of the mechanical origin detecting device according to the present invention will be described. In FIG. 1, assuming that the direction in which the workpiece 6 moves from the switch 11 to the switch 12 side is forward rotation, the switch
When the work 6 exists between 11 and the switch 3, the forward rotation mechanical origin detection method is used. When the work 6 exists between the switch 3 and the switch 12, the reverse rotation mechanical origin detection method is used. Detect the machine origin.

FIG. 3 is a time chart showing the mechanical origin detection operation during normal rotation. In this case, it is the same as the conventional device except that the detection signal ΦO is “H”. Therefore, although duplicate description is omitted here, if the origin shift amount is set to 1 mm (shown by diagonal lines), the origin signal LS is inverted from “H” to “L”, and then the first fall of the marker signal ΦZ. The position of is -1 mm.

The mechanical origin detecting operation during reverse rotation will be described with reference to the time chart of FIG. 4 and the flowchart of FIG. First, when the microcomputer 2 starts, a home return command is output in step P1 and the motor 7 rotates in the reverse direction. The forward / reverse rotation signal ΦR output from the waveform shaping circuit 13 due to the reverse rotation of the motor 7 is “L”, and the detection signal ΦO output from the signal switching circuit 14 is a signal obtained by inverting the marker signal ΦZ. In step P2, it is determined whether or not the origin signal LS is inverted from "L" to "H". If the determination is affirmative, the process proceeds to step P5, and if the determination is negative, the process proceeds to step P3. In the period in which the origin signal LS is in the "L" state without being inverted, the fall of the detection signal ΦO (a signal obtained by inverting the marker signal ΦZ) is determined in step P3. Here, in step P3, as shown in FIG.
At the time points a, b, c, d, and e, the falling edge of the detection signal ΦO is discriminated and the process proceeds to step P4. At step P4, the origin is set at the current position of the work 6 managed by the microcomputer 2 at each time point. The operation of setting 1 which is the shift amount is repeated. Work 6
Moves to contact the switch 3 and the origin signal LS is inverted from "L" to "H" in step P2, the process proceeds to step P5 to stop the motor 7. When the motor 7 stops, the work 6 moves to point Q due to inertia and stops. Since the position of the Q point at which the work 6 moves and stops is managed by the microcomputer 2, the microcomputer 2 measures the amount of movement from the point e to the Q point at which the detection signal ΦO falls. Therefore, in step P6, the motor 7 is normally rotated by an amount obtained by adding the amount of movement of the origin set at the current position to the amount of movement from the point e to the point Q.
When is moved, the work 6 reaches the machine origin.

[Effect of device]

As described above, in the mechanical origin detecting device of the present invention, the marker signal is switched between the forward rotation and the reverse rotation by using the waveform shaping circuit and the signal switching circuit, and the signal obtained by inverting the marker signal during the reverse rotation is used. By doing so, it is configured to eliminate the deviation of the marker signal at the time of forward rotation and reverse rotation, so even if the target object is on the right or left side of the limit switch that outputs the origin signal, the motor can be rotated forward or reverse. It is possible to detect the mechanical origin, and it is not necessary to move the target object to a predetermined side in order to detect the mechanical origin as in the conventional device, and the mechanical origin can be detected promptly.

[Brief description of drawings]

1 to 5 show an embodiment of the mechanical origin detecting device of the present invention, and FIG. 1 is its block diagram and FIG.
The figure is a waveform diagram explaining that there is no deviation even when the motor rotates in the forward direction and the reverse direction even if the marker signal is used. FIG. 3 is a timing chart showing the operation during the forward rotation of the motor. FIG. 5 is a flow chart for explaining the operation of the motor during reverse rotation. Sixth
1 to 8 show an example of a conventional mechanical origin detecting device, FIG. 6 is a block diagram thereof, FIG. 7 is a time chart showing the operation, and FIG. 8 is a flow chart. 1: Target object (work) feeding device, 2: Microcomputer, 3: Limit switch, 4: Origin detection means, 10: Encoder, 13: Waveform shaping circuit, 14: Signal switching circuit.

Claims (1)

(57) [Scope of utility model registration request] 1. A target object feeding device for linearly moving a target object by rotation of a shaft having a feed screw of a predetermined pitch, speed command means for rotating a motor connected to the shaft, and a moving position of the target object. The limit switch and the motor, which are arranged close to each other, output an origin signal which is inverted from a low level to a high level when the target object abuts, and which is inverted from a high level to a low level when the target object is separated. An encoder that outputs a marker signal that is inverted to a high level once per one rotation is provided, and the target object exists on a predetermined side with respect to a limit switch, and the motor is rotated in the forward direction to rotate the target object. When moved in one direction, the origin signal from the limit switch first appeared after being inverted from high level to low level. Position of the target object moved by inertia from the position where the motor was stopped by the marker signal (hereinafter, from the position where the motor stopped to the position where the target object moved due to inertia and stopped) In the mechanical origin detecting device provided with origin detecting means for detecting the amount as an origin shift amount) as a mechanical origin, the encoder is configured to output an A phase pulse and a B phase pulse in addition to the marker signal. A waveform shaping circuit that outputs a high-level normal rotation signal and a low-level reverse rotation signal based on the A-phase pulse and the B-phase pulse from the encoder, and the logic of the normal rotation signal and the marker signal of the waveform shaping circuit during normal rotation. In reverse rotation, the reverse rotation signal of the waveform shaping circuit and the signal obtained by inverting the marker signal are taken as the logic during forward rotation and reverse rotation. A signal switching circuit for switching the power supply signal between the forward rotation signal and the reverse rotation signal is provided, and the origin detection means, in addition to the means for detecting the mechanical origin during the forward rotation, shifts the origin every time the inverted marker signal falls during the reverse rotation. Set the amount as the current position,
When the origin signal from the limit switch reverses from low level to high level, the motor is stopped, the origin is shifted to the movement amount from the current position to the position where the target object moves due to inertia after stopping the motor. A machine origin detecting device comprising means for detecting the machine origin by rotating the motor forward by an amount obtained by adding the quantities.