JPH0325892Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an error confirmation device that automatically records an error between a command value and an actual displacement of a feeding mechanism.

[Background technology] When automatically feeding a cutter or workpiece by a desired amount in an electrical discharge machine or machine tool, it is extremely difficult to completely match the command value and the actual value due to the machining and assembly accuracy of the feeding mechanism. be.

Therefore, in reality, operation is performed on the premise that a certain amount of feed error remains between the two. Such feed errors vary from machine to machine.

Here, it is important to clarify the feed error both in a wide range and in a narrow range. This is because if this is clear, the working conditions can be adjusted so that the feed error can be used without causing problems.

Conventionally, in the feed mechanism, the method used to record the error between the command value and the actual value moved was published in Japanese Patent Application Laid-Open No.
-87690 is known.

This is done by arranging the standard parallel to the screw shaft that is rotated by a pulse motor and feeding the drive unit, and also using a high-precision reader that reads the scale of the standard optically or magnetically on the drive unit. Attach the head and read the scale of the standard with the reading head every time a predetermined number of drive pulses are applied to the pulse motor, and calculate the value or error (difference between the set distance based on the number of drive pulses and the value of the standard). The information is stored in a storage device.

However, this method is expensive because it measures the actual feed amount of the drive unit using a standard and a reading head that optically or magnetically reads the scale of the standard. In particular, in order to accurately measure the actual feed amount of the drive unit, the scale of the standard must be machined with high precision without error over the entire movement process of the drive unit, that is, the entire length of the screw shaft. Machining a scale with high precision over its entire length is not only expensive but also difficult.

Furthermore, for these reasons, it cannot be said that the positional information obtained with the standard scale necessarily has sufficiently high accuracy, and as a result, highly accurate error confirmation cannot be expected. In addition, since the value read by the reading head is the moving position of the drive unit, in order to determine the feed error, a circuit and processing are required to calculate the difference between the read value and the set distance based on the number of drive pulses. It becomes necessary.

[Purpose of invention]

An object of the present invention is to provide an error confirmation device for a feeding mechanism that automatically records this information to improve the workability for error confirmation and, in turn, improve the reliability of the feeding mechanism.

[Structure of the invention] Therefore, in the present invention, in a feeding mechanism that feeds a movable member by a set distance relative to a fixed member based on a command from a control device, as a means for measuring the actual feed amount of the movable member, A reference block in which multiple reference planes are arranged in parallel at set distance intervals, and an analogue body in which a probe is supported so as to be movable within a predetermined range in a direction parallel to the feed direction of the movable member with respect to the neutral axis. By using a formula displacement detector, it can be constructed at low cost. Furthermore, when the movable member is sent based on a command from the control device and the probe of the displacement detector contacts the reference surface of the reference block, the output value of the displacement detector in that contact state can be directly recorded. It is composed of

Specifically, in an error checking device for a feeding mechanism that feeds a movable member by a set distance relative to a fixed member based on a command from a control device, a plurality of reference surfaces arranged parallel to the feeding direction of the movable member are used. a reference block arranged in parallel along the feeding direction at intervals of the set distance, a main body provided on the movable member, and a direction parallel to the feeding direction with respect to the neutral axis as a reference; A displacement detector that has a probe that can be displaced within a predetermined range and outputs an analog signal proportional to the amount of displacement of the probe, and a displacement detector that detects displacement when the probe of this displacement detector is on the neutral axis. an output regulator for shifting the output value of the displacement detector, and a recorder for recording the output value of the displacement detector each time the movable member is sequentially moved a set distance according to a command from the controller, The output value of the displacement detector is shifted to be positive or negative when the measuring stylus is on the neutral axis, or the output value of the displacement detector is 0 when the measuring stylus is on the neutral axis. This feature is characterized in that the probe is shifted in advance so that the output value of the displacement detector becomes positive or negative, and the probe is forcibly positioned in advance in a direction in which the output value of the displacement detector becomes positive or negative.

[Embodiment] FIG. 1 shows the arrangement relationship between the feeding mechanism and the reference block of this embodiment. In the figure, the feed mechanism 1 includes two guide shafts 3 supported parallel to each other between a pair of end plates 2, and a first motor 4 at the center between the two guide shafts 3. The feed screw shaft 5 rotated by the guide shaft 3 is
is supported parallel to the The feed screw shaft 5 and both guide shafts 3 are provided with a first movable body 6 that is slidable on the guide shaft 3 and meshed with the feed screw shaft 5 . 1st
Two guide shafts 8 which are orthogonal to the guide shaft 3 and the feed screw shaft 5 are disposed in parallel to each other on the upper surface of the movable body 6 via a pair of end plates 7, and the guide shafts 8 are arranged in parallel with each other. A second motor 9 in the center between the shafts 8
A feed screw shaft 10 rotated through the guide shaft 8 is rotatably supported parallel to the guide shaft 8. The feed screw shaft 10 and both guide shafts 8 are provided with a structure that is slidable with respect to the guide shaft 8 and that is attached to the feed screw shaft 10.
A second movable body 11 is provided which is meshed with the second movable body 11 . The second movable body 11 has a displacement detector that outputs an analog signal proportional to the amount of displacement of the gauge head 13 when the gauge head 13 is rotationally displaced within a predetermined range with respect to the main body 12 with respect to the neutral axis. A container 14 is attached.

On the other hand, the reference block 21 includes a plurality of reference surfaces 22 ₁ to 22 ₅ arranged in parallel at predetermined intervals along the feeding direction of the first movable body 6 . Here, the dimension between the adjacent reference planes 22 ₁ to 22 ₅ is set to a pitch P corresponding to a set distance that the first movable body 6 moves.

FIG. 2 shows a circuit for controlling the drive of the feed mechanism 1 and recording feed errors. The circuit includes a differential transformer 3 that outputs an analog signal proportional to the amount of displacement of the probe 13 of the displacement detector 14.
1. An output regulator 32 for shifting the output value from the differential transformer 31 when the probe 13 is on the neutral axis, an amplifier 33 for amplifying the output of the output regulator 32, and the first motor. 4 and the second motor 9 according to the command values recorded on the tape, and the control device 3
A recorder 35 is provided for recording the value of the differential transformer 31 applied via the amplifier 33 and the output regulator 32 when a data acquisition command is applied from 4.

The differential transformer 31 includes a primary coil 41 and
two differentially connected secondary coils 42; a core 43 that is directly or indirectly connected to the probe 13 and is displaced in conjunction with the displacement of the probe 13;
It is composed of. Further, the output regulator 3
2 is connected via a resistor 45 to a connection point between a resistor 44 inserted between the output terminals of the secondary coil 42 of the differential transformer 31 and the two secondary coils 42, and is connected to the resistor 45 by operating a knob or the like. It consists of a slider 46 that slides against a resistor 44, and the output value from the differential transformer 31 is shifted depending on the position of the slider 46 with respect to the resistor 44. Here, as shown in FIG. 3A, when the measuring element 13 of the displacement detector 14 is on the neutral axis, that is, when it is perpendicular to the feeding direction of the first movable body 6, 3
So that the output value from 1 indicates a negative value,
Further, as shown in FIG. 3B, when the first movable body 6 moves forward in the feeding direction and the measuring element 13 of the displacement detector 14 contacts the fixed member and is rotated by a predetermined angle, the output value from the differential transformer 31 is The output regulator 32 is set so that the value indicates a zero value.

On the other hand, the control device 34 controls the tape reader 47
The first motor 4 is activated via the driver 48 in accordance with the command value read from the tape by the driver 49.
The second motors 9 are respectively driven through the two motors.
Here, each time the first movable body 6 moves a set distance via the first motor 4, a data acquisition command is given from the control device 34 to the recorder 35. As a result, the recorder 35 records the output value of the differential transformer 31 provided via the amplifier 33 and the output regulator 32 on the recording paper every time a data import command is given from the control device 34. There is.

Next, the operation of this embodiment will be explained. First, the first
The first movable body 6 is moved in the Y direction through the drive of the motor 4, and if necessary, the second movable body 11 is moved in the X direction through the drive of the second motor 9. After the probe 13 of the detector 14 contacts the first reference surface 22 ₁ , it is moved to the position shown in FIG. 3B. Here, the differential transformer 3
Output regulator 32 so that the output value of 1 becomes 0 value.
Adjust it. In other words, when the probe 13 of the displacement detector 14 is on the neutral axis in FIG. 3A, -
Adjust in advance so that it becomes V. After adjusting the reference planes 22 ₁ to 22 ₅ one after another in this way, error checking is performed.

In the error confirmation work, after returning the first movable body 6 to its original position, the control device 34 gives a command value corresponding to the pitch P to the first motor 4 via the driver 48. Then, the first movable body 6 is moved by driving the first motor 4 in accordance with the command value. At this time, before the first movable body 6 moves by the command value, the second motor 9
The second movable body 11 is moved by driving, and the measuring element 13 of the displacement detector 14 is brought into contact with the reference surface 22 ₁ . Eventually, when the first movable body 6 comes to rest after moving by the command value, a data capture command is issued from the control device 34 to the recorder 35. Then, the output value of the differential transformer 31 at that time is recorded on the recorder 35.

At this time, the output value of the differential transformer 31 is −V ₁
Then, the actual feed amount of the machine is V ₁ for the command value P.
It will be shorter by the distance corresponding to . Also, ±0
Then, the actual feed amount of the machine will be equal to the command value P. Furthermore, if it is +V ₂ , the actual feed amount of the machine is ahead of the command value P by V ₂ .
Therefore, by plotting this output for each of the reference planes 22 ₁ to 22 ₅ , a so-called narrow range error diagram can be obtained over the entire stroke. Therefore, for example, by directly determining the relationship between the origin position and the n-th reference plane 22n, a so-called wide range error diagram can be easily obtained.

Therefore, according to this embodiment, since the feed error of the feed mechanism 1 can be automatically recorded, the work efficiency for error confirmation can be improved, and the reliability of the feed mechanism 1 can be improved. .

In addition, as a means for measuring the amount of feed of the first movable body 6 in the Y direction, the reference block 21 and the analog displacement detector 14 are used for measurement. It is cheaper than one that uses a reading head to read the scale.

Furthermore, the output adjuster 32 shifts the output value of the displacement detector 14 to a negative value (-V) when the probe 13 of the displacement detector 14 is on the neutral axis. When the first movable body 6 is sent based on a command from the control device 34 and the probe 13 of the displacement detector 14 comes into contact with the reference surface of the reference block 21, the output value of the displacement detector 14 is directly detected. It can be recorded as a feed error. In other words, there is an advantage that no circuit or processing is required to determine the feed error. This also has the advantage that assembly manufacturing and inspection can be easily performed.

In addition, since the reference position is provided by the reference block 21, the reference plane serving as the reference position can be positioned with high accuracy, and as a result, highly accurate error confirmation can be expected.

Furthermore, by providing a plurality of reference surfaces 22 ₁ to 22 ₅ and sequentially confirming the feed error for these reference surfaces 22 ₁ to 22 ₅ , a so-called narrow range error can be obtained, and the reference surfaces 22 ₁ to 22 ₅ are If selected, a so-called wide range error diagram can also be easily created.

Furthermore, since records can be taken, excessive errors can be adjusted,
The error can be reduced, and as a result, it can also contribute to higher precision of the feeding mechanism.

In addition, in the above embodiment, the probe 13 is connected to the main body 12.
Although the displacement detector 14 is used, the measuring element 13 may be displaced parallel to the main body 12, as shown in FIG. 4, for example.

Further, in the above embodiment, when the probe 13 of the displacement detector 14 is in a free state, the output of the differential transformer 31 indicates a negative value, that is, the probe 13 of the displacement detector 14 is configured to indicate a negative value.
The output adjuster 32 is set so that the output value of the probe 13 indicates 0 value when the contact point contacts the fixed member and is rotated by a predetermined angle. The output value of the differential transformer 31 is set to indicate 0 value when the measuring head 13 of the instrument 14 is in a free state, and the measuring head 1 is set as shown in FIG. 5B.
3 forcibly rotated in the feeding direction of the first movable body 6 (the direction in which the output value of the differential transformer 31 indicates a negative value) by the spring 51 or the like, the same effect as in the above embodiment can be obtained. can be expected.

Furthermore, in the above embodiment, in order to cope with the feed error direction, the output value of the differential transformer 31 is set to indicate a negative value when the probe 13 of the displacement detector 14 is in a free state. The output value of the differential transformer 31 may be either positive or negative. Furthermore, the displacement detector that outputs an analog signal proportional to the amount of displacement of the probe may not be a differential transformer.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an error confirmation device that can directly record the feed error of the feed mechanism with an inexpensive and simple configuration.

[Brief explanation of drawings]

FIG. 1 is a front view showing the arrangement relationship between the feeding mechanism and the reference block of this embodiment, FIG. 2 is a block diagram showing its circuit, and FIG. 3 is an explanatory diagram showing the state of the probe of the displacement detector. FIG. 4 and FIG. 5 are diagrams each showing a modification of the displacement detector. 1... feeding mechanism, 6... first as a movable member
movable body, 11... second movable body as a movable member, 12... main body, 13... measuring element, 14... displacement detector, 21... reference block, 22 ₁ to 22 ₅
... Reference surface, 32 ... Output regulator, 34 ... Control device, 35 ... Recorder.

Claims (1)

[Claims for Utility Model Registration] An error checking device for a feeding mechanism that feeds a movable member relative to a fixed member by a set distance based on a command from a control device, comprising a plurality of a reference block having reference planes arranged in parallel along the feed direction at intervals of the set distance; a body provided on the movable member; and a body parallel to the feed direction with respect to the neutral axis as a reference. A displacement detector has a measuring point that can be displaced in a certain direction and within a predetermined range, and outputs an analog signal proportional to the amount of displacement of the measuring point, and when the measuring point of this displacement detector is on a neutral axis. an output adjuster for shifting the output value of the displacement detector; and a recorder for recording the output value of the displacement detector each time the movable member is sequentially moved a set distance according to a command from the control device. , when the measuring stylus is on the neutral axis, the output value of the displacement detector is shifted to be positive or negative, or when the measuring stylus is on the neutral axis, the output value of the displacement detector is shifted What is claimed is: 1. An error confirmation device for a feeding mechanism, characterized in that the probe is shifted so that the value becomes 0, and the probe is forcibly positioned in advance in a direction in which the output value of the displacement detector becomes positive or negative.