JPH0671692B2 - Cam vertex position indexing method and control device therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cam apex position indexing method for determining the apex position of a workpiece such as a cam having a curved contour line, and a control device therefor. More specifically, the present invention relates to a cam vertex position indexing method for indexing the cam vertex position where the lift amount of the follower of the cam is maximum, and a control device therefor.

[Prior Art] Although various types of cams are known, for example, there is a tangent cam made by connecting an arc and a straight tangent. Various processing methods such as cutting and grinding are known as tangential cam processing methods, but the outer and inner circumferences are cut with a milling cutter on a milling machine, turning center (which can be milled on a lathe), etc. There is a way. For example, when a key groove is cut from a forged black-skin material to the shaft of a tangential cam at the turning center with reference to the cam shape, the base circle and the apex where the displacement of the follower is the maximum If it is not determined and the positioning is performed with reference to the apex portion and the like and cutting is performed, the machining allowance cannot be sufficiently obtained.

Conventionally, for indexing this apex position, attach a touch sensor to the tool spindle and gradually move it closer to the tangent cam side, and slowly rotate the tangent cam (C-axis (tangent cam Direction of the spindle attached via (Z
Axial direction) line)), the touch sensor detects the angular position when the tangential cam first touches,
This angular position is defined as the apex (at the angular position of the C axis line).

In JP-A-63-2651, the amount of eccentricity of a workpiece is measured by a displacement sensor, the angle at which the eccentric distances at the starting point angular position and the ending point angular position are equal is detected, and the angular center is determined. An eccentric position automatic detection method for an eccentric shaft that is determined to be the apex is described.

[Problems to be Solved by the Invention] However, since the tangential cam is rotated about the C axis many times at low speed, it takes time to measure the apex. Also, because the displacement gauge sensor contacts the workpiece to detect the amount of eccentricity,
It is impossible to measure beyond the measuring range of the displacement sensor. Therefore, it is impossible to detect the vertex position of the work piece having a large eccentricity. In addition, it cannot be applied to a workpiece such as black leather with many variations in shape.

An object of the present invention is to provide a cam vertex position indexing method for indexing a vertex of a workpiece having a curved surface such as a cam in a short time, and a control device therefor.

Another object of the present invention is to provide a cam vertex position indexing method for indexing the projection position of a workpiece having a projection with a large eccentricity amount, and a control device therefor.

[Means for Solving the Problems] A first invention is a method for detecting a vertex position of a workpiece having a cam, in which a radial position of a contour line is displaced with respect to a rotational angle position of a shaft, by a touch sensor, A step of positioning the touch sensor at a predetermined position in the radial direction of the work piece; a normal rotation step of rotating the work piece in the normal rotation direction around the axis of the shaft; A first detection step of detecting, as a first rotation angle position, a rotation angle position of the work piece when the contour line of the work piece and the touch sensor come into contact with each other; After detecting the rotation angle position of 1, the reversing step of rotating the workpiece in the reverse direction around the axis of the shaft, and the contour line of the workpiece and the touch sensor are contacted by the reversing step. When said A second detection step of detecting the rotation angle position of the workpiece as a second rotation angle position, and the first rotation angle position and the second rotation angle position are added, and a half angle position thereof is added. Is calculated as an intermediate angular position, and the intermediate angular position is estimated to be the apex position of the contour line of the workpiece.

2nd invention is a control apparatus which implements a cam vertex position indexing method, A touch sensor which outputs a contact signal when it contacts the said to-be-processed object, The said to-be-processed object is rotationally driven around the said axis line. First
Servo motor (15), a second servo motor (18) for driving the relative movement of the touch sensor and the workpiece in the radial direction of the workpiece, and the workpiece. Rotation angle position detection means for detecting a rotation angle position of the work piece when the touch sensor and the work piece contact each other and output a contact signal by rotating, and the work piece is rotated in a forward rotation direction. An intermediate angular position between a first rotation angle position obtained when the touch sensor is brought into contact with the touch sensor and a second rotation angle position obtained when the workpiece is rotated in the reverse direction to come into contact with the touch sensor. And a vertex calculating section (37) for calculating.

[Operation] The touch sensor is positioned on the outer periphery of the workpiece, and the workpiece is normally rotated. The first point on the contour line of the workpiece is brought into contact with the touch sensor, and the rotation angle position at the time of contact is detected, and then the workpiece is reversed to bring the second point on the contour line into contact with the touch sensor. Then, the rotation angle position at the time of contact is detected, and an intermediate angle position between the rotation angle position of the first point and the rotation angle position of the second point is used as the apex of the contour line of the workpiece to form a cam shape. This is a method of indexing the apex of the workpiece.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows the principle of the present invention. Taking the tangential cam 1 as an example, the contour line 2 of the tangential cam 1 has a radius R
Of the basic circle 3, a tangent line 4 to the basic circle 3, and a concentric circle 5 having a radius R ₁ concentric with the basic circle 3. To measure, first touch the contact 21a of the touch sensor 21 having a radius r with X.
The position is fixed at the point a, which is on the axis and has a radius larger than the base circle 3. Point a is a position on the X-axis line obtained by adding α to the radius R of the basic circle 3 (where α> r). The tangential cam 1 is rotated forward about the C axis. A on contour line 2
The outer circumference of the contact 21a of the touch sensor 21 comes into contact with the point.

The rotation angle position in the C-axis direction at the point A that has made contact is detected and stored. Next, when the C axis is reversed, the axis cam 1
The point B, which is one point on the outer circumference of the contact, is the contact 21a of the touch sensor 21.
It contacts the outer circumference of and detects the rotation angle position in the C-axis direction. It is estimated that the rotational angular position of the point A and the intermediate angular position on the bisector of the rotational angular position of the point B are the vertex C of the tangential cam 1. The angular position of the vertex C can be detected within one reciprocating rotation. However, the vertex C of the tangential cam 1 does not always exist on the bisector. It is just an estimated position.

Cam Apex Indexing Control Device FIG. 2 is a functional block diagram of a cam vertex indexing control device when the above-described principle of the present invention is implemented in a turning center. The CPU 11 is a central processing unit of the index control device. A bus 12 to which I / O devices, memories, etc. are connected is connected to the CPU 11. The terminal 13 is equipped with a keyboard and performs input / output and display of data, programs and the like. The terminal 13 is connected to the bus 12 via the interface 14.

The cam shaft servomotor 15 is a drive motor that rotates around the basic circle 3 of the tangential cam 1 (C axis). The cam shaft servomotor 15 is connected to and controlled by the bus 12 via an interpolator 17 and an amplifier 16. The current position of the camshaft servomotor 15 in the C-axis direction is also detected. The cam shaft servo motor 15
In this embodiment, since it is a turning center, it also serves as an attachment holding the workpiece and a spindle motor for driving the spindle. X-axis servo motor 18 has touch sensor 21
Is to drive. X-axis servo motor 18 is an interpolator
20, controlled via amplifier 19. Cam axis servo motor
The 15 and the X-axis servomotor 18 are provided with detectors such as pulse encoders (not shown), and their feedback outputs are fed back to the interpolator 17 and the interpolator 11, respectively.

The touch sensor 21 is connected to the bus 12 via the interface 22.
It is connected to the. Therefore, when the contact 21a of the touch sensor 21 detects the tangential cam 1, the position of the C-axis at the moment of detection, that is, the output value from the feedback detector of the cam shaft servomotor 15 is added or subtracted from the current value counter value. Can be detected. This detection method is well known and will not be described in detail. The machining program memory 23 is a memory that stores a program for machining the shape of the tangential cam 1 by the turning center. The measurement program memory 24 is a memory for storing a program in which details of the measurement operation of this embodiment described later are programmed.

The measurement information memory 26 is a memory for storing data obtained by measuring the tangential cam 1 as described above. In particular,
A point which is the contact point on the contour line 2 of the tangential cam 1 described above,
This is a memory that temporarily stores the angular positions on the C axis of the B point, the C point, and the D point that is the measured apex position, each time it is measured and calculated. The sensor position memory 27 is the touch sensor 21.
It is a memory for storing measurement positions and data for the measurement of. The point a (R +
α), point b (R ₁ + r) and point e (R ₁ + r + β) described later.

The measurement setting data memory 28 is a memory that stores setting values that can be freely set by the operator. A value α (α that is appropriately selected for calculating the point a from the base circle 3 of the tangential cam 1
> R), β for calculating the radius r, e point of the contact 21a of the touch sensor (a value close to the machining allowance), and the like. Point a calculation unit
Reference numeral 29 is an adder that adds the radius R of the basic circle 3 and the set constant α when the command to measure the vertex is issued.

The value α added by the a point calculation unit 29 is written in a predetermined storage position of the sensor position memory 27 by the a point writing means 30. The point b calculator 32 adds the radius R ₁ of the concentric circle 5 of the basic circle 3 and the radius r of the contact 21a of the touch sensor 21. The b-point calculation unit 32 starts calculation when the AND circuit 31 issues a calculation command for the b-point. The calculation result from the b point calculation unit 32 is b
It is input to the point writing means 33. b-point writing means 33
Writes the value in the memory position of point b of the sensor position memory 27.

The point e calculation unit 35 determines the radius R _{1 of the} concentric circle 5 and the touch sensor 21.
This is a calculation unit that adds the radius r of the contact 21a and the set value β. The e-point calculation unit 35 starts calculation when the calculation instruction of the e-point is issued from the AND circuit 34. The calculation result is sent to the e-point writing means 36. The e-point writing means 36 writes this calculation result in the memory position of the point e of the sensor position memory 27.

When the calculation command is issued, the vertex index calculation unit 37 is an intermediate value between the rotation angle position of point A and the rotation angle position of point B (A +
B) / 2 is calculated. The point C (angular position) that is the result of this calculation is the apex on the contour line 4 of the tangent cam 1. The C point writing means 38 writes the C point in the measurement information memory 26. Comparator
39 is to compare the first measured value and the second measured value. If the calculated vertex position is different from the angular position of the point C, the second measured value is recognized as a new vertex C. This detected value rewrites the memory of the vertex C of the measurement information memory 26 as a new vertex C.

Operation of Cam Top Indexing Device The flowchart shown in FIG. 3 is a flowchart of the cam indexing control device described above. When the measurement command is issued, the a point calculation unit 29 and the b point calculation unit of the cam vertex indexing control device
32, the point e calculator 35 draws out the necessary data from the cam shape data memory 25 or the like to start the calculation, and stores the calculation result in the sensor position memory 27 (step P ₁ ). Contact 21a of the touch sensor 21 moves to the base circle 3 position greater than a point (Step P _2).

In step P ₃ , it is determined whether the home position is fixed. The tangential cam 1 is rotated by the cam shaft servomotor 15 about the C axis (step P ₄ ). Contact 21a of touch sensor 21 and tangential cam 1
When the touch sensor 21 makes contact with the contour line 2 of the contact point A, the touch sensor 21 detects and measures the rotational angular position of the contact point A, that is, the angular position of the point A which is the angular position around the C axis (step P ₅
~ P ₆ ).

When detecting the contact point A, to immediately reverse the cam axis servomotor 15 (Step P _7). This reverse rotation speed is fast forward at first and slow feed rotation near the next contact point B. This is because, after detecting the contact point A, the position of the next contact point B can be predicted to some extent. The following is the contact point B rotational angular position, that detects the center and the point B rotational angular position C-axis like the A point rotational angular position of the contact point A in (Step P ₈ to P ₉₎ the contact point A An intermediate angle position between the rotation angle position of the point A and the rotation angle position of the contact point B at the point B about the C axis is the vertex of the tangential cam 1, in other words, the angle position of the concentric circle 5 is the vertex angle position C of the tangent cam. Considering it as a point, the reference angular position of the C-axis of the tangential cam 1 is provisionally set (step P ₁₀
~ P ₁₁ ).

The touch sensor 21 is moved to the retracted position outward in the X-axis direction (direction away from the tangential cam 1) (step P ₁₂ ).
The tangent cam 1 is rotated, for indexing the tangent cam 1 provisional C axis reference position (step P _13). The touch sensor 21 is moved at a low feed speed to the position b where the radius R _{1 of the} concentric circle 5 which is known in advance and the radius r of the contact 21a of the touch sensor 21 are integrated (step P ₁₄ ). The tangent cam 1 are rotationally driven, the touch sensor 21 and tangents cam 1 detects a vertex angle position C first contacts (step P _15).

It is determined whether or not the detected coordinate values of the vertex C in the radial direction are larger than expected (step P ₁₆ ). If NO, remove the work because it is an abnormal work such as the material size is small (step P ₂₄ ).

If it is larger than planned, the work can be processed. That is, it is a judgment as to whether or not a predetermined minimum machining allowance is included. Long as have this minimum or machining margin, the process proceeds to step P _17, is moved further outside position than the position b of the touch sensor 21 (in this example, beta = about 0.5 mm),
That is, it is moved to the position e (step P ₁₇ ). The tangential cam 1 is rotated once (step P ₁₈ ), and it is determined whether or not the touch sensor contact 21 a contacts the apex of the tangential cam 1 (step P ₁₉ ). If there is contact, the rotation angle position at the time of contact is set as the rollover angular position of the contact point D (step P ₂₀ ).

It is determined whether or not A <D <B or A>D> B in step P _22. If this judgment is Yes, regarded as new vertex angular position C of the rotational angular position of the point D in step P _23.
That is, if it is between the A point rotation angle position and the B point rotation angle position and is not the vertex angle position C of the above-described calculation result, this D point rotation angle position is set to the vertex angle position C of the workpiece.
To consider. And indexing the tangent cam 1 with respect to this new vertex angular position C (step P _23), for machining the tangent cam 1. Further, the position of the cam apex can be indexed even in a shape having variations such as a black skin material to be processed.

[Effects of the Invention] As described in detail above, the present invention can shorten the time for indexing the cam apex. The vertex can be indexed in a short time even for a work piece with a large amount of eccentricity.

[Brief description of drawings]

FIG. 1 is a view showing the principle of the present invention, FIG. 2 is a cam vertex position indexing control device, and FIGS. 3 (a) and 3 (b) are flowcharts of the cam vertex indexing control device. 1 ... tangential cam, 3 ... basic circle, 21 ... touch sensor,
29 ...... a point calculation unit, 32 ... b point calculation unit, 35 ... e point calculation unit, 37 ... vertex index calculation unit, 39 ... comparator

Claims (2)

[Claims] 1. A method for detecting, with a touch sensor, an apex position of a work having a cam whose radial position of a contour line is displaced with respect to a rotational angle position of a shaft, wherein the touch sensor is a radius of the work. Direction, a normal rotation step of rotating the workpiece in the forward direction around the axis of the shaft, and a contour line of the workpiece and the touch sensor by the forward rotation step. And a first detection step of detecting the rotation angle position of the workpiece as a first rotation angle position when and are contacted, and after detecting the first rotation angle position in the first detection step, A reversing step of rotating the work piece in the reverse direction around the axis of the shaft, and a rotation angle position of the work piece when the contour line of the work piece and the touch sensor come into contact with each other in the reversing step. The second The second detection step of detecting the rotation angle position, the first rotation angle position and the second rotation angle position are added, and the half angle position thereof is obtained as the intermediate angle position, and this intermediate angle And a cam vertex position estimating step of estimating a position as a vertex position of the contour line of the workpiece. 2. A control device for implementing the cam vertex position indexing method according to claim 1, wherein a touch sensor that outputs a contact signal when contacting the work piece, and the work piece around the axis line. To drive to rotate first
Servo motor (15), a second servo motor (18) for driving the relative movement of the touch sensor and the workpiece in the radial direction of the workpiece, and the workpiece. Rotation angle position detection means for detecting a rotation angle position of the work piece when the touch sensor and the work piece contact each other and output a contact signal by rotating, and the work piece is rotated in a forward rotation direction. An intermediate angular position between a first rotation angle position obtained when the touch sensor is brought into contact with the touch sensor and a second rotation angle position obtained when the workpiece is rotated in the reverse direction to come into contact with the touch sensor. And a vertex calculating section (37) for calculating.