JPH0712585B2 - Automatic work recess measuring device for machine tools - Google Patents

Description

TECHNICAL FIELD The present invention relates to a workpiece recess automatic measuring device for a machine tool,
In particular, the present invention relates to a work recess automatic measuring device for a machine tool that is suitable for detecting a work recess on the circumference and measuring the angular position of the work with high accuracy.

[Conventional technology]

Conventionally, when drilling a circular surface of a workpiece, as shown in FIG. 5, as numerical data indicating the hole positions H1, H2, H3, ..., Angles θ1, θ2, θ3, from the center point of the circular surface, Is used to measure the position of the recess Q formed in the circumferential surface of the work by the touch sensor Ts and use it as the angle reference point.

FIG. 6 is an explanatory view showing an example of a touch sensor suitable for the above method. As shown in FIG. 6A, when the sensor Ts is brought into contact with the work W, a closed circuit C is formed. The ring core R is arranged at the base of the sensor Ts. The ring core R is composed of an exciting core ER and a detecting core SR, as shown in FIG.
If ER sends a current to circuit C and a closed circuit is formed,
The detection core SR detects the circulating current and emits a signal. When the touch sensor Ts is brought into contact with both side wall surfaces of the recess and the intermediate value of the angle at that moment is calculated, the angular position of the center point of the recess can be obtained.

[Problems to be solved by the invention]

As described above, there are some problems in the measuring method in which the sensor probe is moved into the concave portion of the work and then the probe is moved in the width direction of the concave portion to touch the side wall surface.

One of them is whether the operation of touching the surface of the work piece with the probe at a predetermined pitch can correctly enter the concave portion, and if the pitch is selected incorrectly, the concave portion will pop out. Even if it can be inserted, if it is not close to the center of the recess but is too close to the side wall surface, a precise measurement result cannot be obtained for the following reasons. That is, strictly speaking, the driving means provided in the machine tool is disliked because it lacks stability in rising, and if the probe is moved too close to the side wall surface, the measurement operation should be performed at the rising speed of the rising portion. become. Further, even if the side wall surface of the workpiece to be contacted is immediately determined by the contact at the initial stage of movement of the probe, an accurate side wall surface position cannot be obtained, and it cannot be endured if the tolerance for the measurement of the center point is severe.

The present invention has been devised in view of such problems, and automatically selects a suitable measurement start point, improves measurement accuracy, and provides a machine tool having an excellent effect of setting a work reference point. An object is to provide an automatic workpiece recess measuring device.

[Means for solving problems]

In the present invention, as a means for solving the above-mentioned problems, as shown in FIG. 1, a concave portion formed on a work surface is moved in a concave portion width direction and a concave portion depth direction of a single probe. Is a work recess automatic measuring device of a machine tool for measuring the position in the width direction of the recess formed on the work surface by touching the tip of the probe to the work surface at equal intervals at a predetermined width direction. , The predetermined widthwise pitch is set to a value within a range of 1 to 1/2 times the expected width of the recess, and the first stylus scheduled as the approximate position of the recess is tried from the position The stylus is tried by moving the probe in the depth direction of the concave portion until the probe enters the concave portion in a desired widthwise area so as to alternately move away from each other in the widthwise direction at a predetermined widthwise pitch. The concave part search processing part and the case where the probe can enter the concave part. If the approach is the first time, re-entry is attempted by moving the probe in the depth direction at both positions adjacent to the pitch interval, and if the approach is the second time or later, the outside of the pitch interval is attempted. At the side position, the measurement start point search processing unit that attempts re-entry by moving the probe in the depth direction, and when the number of times that the recess can be entered is one, the entry position in the width direction is set as the measurement start point, and the recess When the number of times the vehicle has been able to enter is two times, a measurement start point setting unit having a measurement start point at an intermediate point in the width direction thereof and a recess width direction from the set measurement start point to both side wall surfaces of the recess And a concave portion measurement processing unit for measuring the concave portion by touching the probe by the movement of the probe, and an automatic workpiece concave measuring device for a machine tool.

[Action]

The present invention is used to measure or confirm the position of a recess, and normally the size of the recess, such as the groove width, is input as data. The probe pitch of the probe is set within a range of 1 to 1/2 times the predetermined width of the recess, so that if the probe is tried at that interval, the probe always enters the recess at least once, and The measurement start point search processing unit is provided because it gives a condition that it can enter at most twice and never more than three times.
The reason why the two stylus are tried at 20 is to prevent missing the position that the stylus can enter twice if the first stylus can enter the concave portion. At least one of the adjacent positions on one side is re-entered, is the approach to a position that can be entered only once as shown in FIG. 2 (a), or as shown in FIG. 2 (b). This is to confirm whether it is one of the positions that can be entered twice. Then, if the position is as shown in FIG. 2 (a), it is almost at the center, and that position can be used as a measurement starting point without any problem.
If the position is as shown in FIG. 2 (b), the measurement start point avoiding the rising region can be obtained by calculating the midpoint between both approach positions.

As a relationship that more preferably satisfies the above, if the maximum allowable error that both side walls can uniformly allow for the predetermined width W of the recess is α ₀ , in the case of FIG. (A), 2P = W + 2α ₀ ... (1), and in the case of Fig. (B), P = W-2α ₀ ... (2), and from both equations, it is desirable to divide P / W = 2/3 as a predetermined pitch. The ratio is obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a view of an automatic workpiece recess measuring device embodying the present invention.
It is a block diagram which shows an example. In Fig. 3, the work recess automatic measurement device also serves as the central controller of the NC machine tool.
CPU1 and display 2 with keyboard that is an input / output means
And its input / output port 2a, touch sensor 3, detection circuit 3a
And its interface 3b, a motor 4, an amplifier 4a and an interpolator position control circuit 4b, a register 5 for coordinate value data fed back from the motor 4, and a storage means 6 for storing an NC machining program and work reference point data. The recessed portion search processing unit 10, the measurement start point search processing unit 20, the measurement start point setting unit 30, and the recessed portion measurement processing unit 40 are roughly configured.

FIG. 4 is a flowchart of the operation procedure of the embodiment. The apparatus of the above embodiment will be described below in more detail with reference to the flowchart and the block diagram of FIG.

The device of the above embodiment starts its operation when the measurement start command from the CPU 1 is input to the AND gate 101. The concave portion search processing unit 10 is a processing unit that controls the trial of the stylus, and the concave portion search operation in the present invention is performed in the circumferential direction of the work surface from the position where the stylus is first tried, as shown in FIG. The stylus is to be repeated until the probe enters the recess so as to move away from each side twice at regular intervals. Regarding the position where the stylus is first performed, the concave portion is arranged at an approximate position where the probe can easily enter when attaching the work. Therefore, the search area is limited, and the range can be easily set by limiting the number of stylus. The present invention is not limited to the case of measuring the groove on the circumferential surface, but as shown in FIG. 7 (b),
It can also be generally applied to a concave portion on a plane. In this case, the searching operation is performed while moving from the position where the probe Ts first contacts the work to both sides in the concave portion width direction at equal intervals. The pattern of such a search operation is input to each gate as the setting data 7. The setting data 7 includes, for example, the following items.

R: Measurement position radius Z1; Work surface position Z2; Recess bottom surface position W; Recess width θ: Recess center position angle A; Search area (sometimes indicated by nmax) First, the search number counter 8 is set to n = 1. After the initial setting, the setting data 7 is fetched from the AND gate 101 to the recessed part search operation data setting part 11 of the recessed part search processing part 10, and the recessed part search operation processing part 12 displays the data as the second stage of the flow. At the first position at the approximate position of the recess at
The search position is approached for the second time, and the search is performed as the second stage of the flow.

In the first approach and search, if the probe contacts the surface position Z1 instead of the concave part of the workpiece,
A signal is input to the search pitch calculation unit 13 via the AND gate 102, and the calculation of P = 2 / 3W described in FIG.
Advance 1 and return to the first stage of the flow. The search is repeated until a concave portion is detected or the number of searches n reaches the limited number, and when the limited number is reached, an alarm is generated.

If the probe can enter the recess, AND gate 10
The processed signal is input to the search number determination unit 21 of the measurement start point search processing unit 20 via 3, and as the stage of the flow, when the approach is the first time, the data for further searching the two points on both sides Is set by the measurement start point search operation first setting unit 22, and if it is the second time or later, data for searching one point on the outer side is set by the measurement start point search operation second setting unit 23, and Either one is selected by the OR gate 104, and the measurement start point search processing unit 24 executes the selection.

When the probe can enter the recess, the respective coordinate values are transferred through the AND gates 105 and 106 to the first coordinate value register 31 and the second coordinate value register of the measurement start point setting unit 30.
When it is taken into 32 and the approach is only once as shown in FIG. 7 (c), the instruction is input from the AND gate 107 to the AND gate 108, so only the first coordinate value is the measurement start point. When it is input to the first setting unit 33, branched to the right of the second stage of the flow, the first entry position is set as it is as the measurement start point Sp, and there are two entries as shown in FIG. 7 (d). Inputs both coordinate values to the midpoint calculation unit 34, branches to the left in the second stage of the flow, and the measurement start point second setting unit 35 sets the midpoint between the two entry positions to the measurement start point. Set to Sp.

One of the set measurement start points is the OR gate 10.
The signal is output to the concave portion measurement processing unit 40 via 9 and, as the second stage of the flow, the concave portion measurement operation processing unit 41 performs the measurement operation from the measurement start point to both side wall surfaces of the concave portion, and the AND gate.
The center point calculating unit 43 calculates the coordinate values of the both side wall surfaces taken into the recess width coordinate value register 42 via 110, and the calculated center point is used as the center point of the recess, and the recess center point position setting unit 44
Then, as the step of the flow, it is set and stored in the work reference point memory 62 in the storage means 6.

Since the workpiece reference point in this embodiment is a measurement operation from substantially the center point of the concave portion, the accuracy is improved as compared with the conventional one, and it is possible to sufficiently withstand strict tolerances.

〔The invention's effect〕

As described above, according to the present invention, an automatic work recess measuring device for a machine tool that automatically selects a suitable measurement start point, improves measurement accuracy, and exerts an excellent effect in setting a work reference point. Can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the basic configuration of the present invention, FIG. 2 is an explanatory diagram of the basic principle of the present invention, and FIG. 3 is a block diagram of one embodiment of the present invention. FIG. 4 is a flow chart of the operating means of the embodiment, FIG. 5 is an explanatory view of a general example of concave portion measurement, and FIG.
FIG. 7 is an illustration of an example of the touch sensor, and FIG. 7 is an illustration of measurement operation. 1; CPU, 2; input / output means, 3; touch sensor, 4; position control drive means, 5; coordinate value data register, 6; storage means 10; concave portion search processing unit, 20; measurement start point search processing unit, 30: measurement start point setting section, 40: concave section measurement processing section, Ts: touch sensor and its probe, P: measurement pitch, W: concave section width.

Claims (1)

[Claims] 1. A recess formed on a work surface is moved by moving one probe in the width direction of the recess and in the depth direction of the recess.
A workpiece recess automatic measuring device for a machine tool, wherein the tip of a probe is touched at an equal interval to a work surface at a predetermined pitch in the width direction, and the position in the width direction of a recess formed on the work surface is measured. The specified width pitch is 1 to 1/2 the planned width of the recess
It is set to a value within a range of double, and the desired position is set so that the first stylus scheduled as the approximate position of the recess is alternately moved to both sides in the width direction at predetermined pitches in the width direction from the position at which the stylus is tried. Within the widthwise area, until the probe enters the recess,
When the probe can enter the recess, if the probe is able to enter the recess for the first time, the depth is detected at both adjacent positions of the pitch interval. Re-entry is attempted by moving the probe in the depth direction, and when the approach is the second time or later, a re-entry is attempted by moving the probe in the depth direction at the position on the outer side of the pitch interval. When the number of times the processing part has entered the recess is one, the position in the width direction is set as the measurement start point, and when the number of times the product can be entered into the recess is two, the intermediate point in the width direction is set. A measurement start point setting unit that is a measurement start point, and a recess measurement processing unit that measures the recess by causing the probe to stylus by moving from the set measurement start point to both side wall surfaces of the recess in the recess width direction. Machine tool characterized by being equipped Automatic workpiece recess measuring device for machines.