JPH074742B2 - Tracer head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tracer head used as a component of a machine tool copy control and three-dimensional coordinate measuring device, a digitizing machine, or the like.

<Prior Art> This type of tracer head has three linear movement axes (X, Y, Z) arranged at right angles to each other as shown in FIG. 6 and two axes (X, Y) as shown in FIG. There is one in which the linear movement axis (Z axis) is combined with the swiveling movement axis. In the figure, A indicates an X-axis movement mechanism, B indicates a Y-axis movement mechanism, and C indicates a Z-axis movement mechanism.

A tracer head having a biaxial (X, Y) turning motion mechanism needs to detect a turning motion in a plane (XY plane) by breaking it down into axial displacements (X, Y) in each axial direction. The tracer head currently being implemented will be described below.

The first tracer head, as shown in FIG. 7, detects the amount of rotation of the pivot shaft 13 (pivot). In FIG. 7, 1 is a pivot, 2 is an X-axis displacement detector, 3 is a Y-axis displacement detector,
Reference numeral 4 is a measuring pressure generating spring, and 5 is a measuring needle.

The second tracer head is, as shown in FIGS. 8 and 9, a detector having a gap for absorbing movement in the direction perpendicular to the detection direction. In FIGS. 8 and 9, 6 is a detection cylinder, and 7 is a detector.

The third tracer head is, as shown in FIG. 10, a combination of a mechanical universal joint, for example, a spherical bearing, with an X, Y linear motion mechanism using parallel leaf springs. In FIG. 10, 8 is an X, Y linear motion mechanism, 9 is a detector, and 10 is a universal joint.

<Problems to be Solved by the Invention> In the above conventional configuration, the first tracer head is suitable for large displacement, but the resolution of detection is poor and the measurement pressure generating springs do not interfere with each other in the X and Y directions. Need to be incorporated into.

Further, the second tracer head is not suitable for an object requiring a large displacement because its detection range is limited by the gap in the direction perpendicular to the detector.

Further, the third tracer head causes friction in the universal joint portion and causes hysteresis, and it is necessary to attach a relief mechanism in the Z direction by the turning motion.

In view of the above-mentioned problems, the present invention is frictionless, can convert motion in a no-clash method, has a simple structure, and can absorb a change in the height direction due to the turning motion of a turning shaft by the deflection of a diaphragm such as a thin leaf spring. The purpose of the present invention is to provide a tracer head capable of large displacement regardless of the detector.

<Means for Solving Problems> The problem solving means according to the present invention is based on the tracer head main body 11
Is supported so that it can be swiveled in the XY plane, and a measuring needle is attached to the lower end.
A displacement detecting swivel shaft 13 having 12, a Z-axis displacement mechanism 14 provided on the swivel shaft 13, a Z-axis detector 15 for detecting the displacement amount of the Z-axis displacement mechanism 14, and a main body 11 The X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism 17 for converting the rotary motion of the rotary shaft 13 into the linear motion components in the X-axis direction and the Y-axis direction, and the displacement amount of the X-axis linear motion mechanism 16 are detected. X-axis detector 18
Y-axis detector 19 for detecting the amount of displacement of the Y-axis translation mechanism 17
And the upper end of the rotary shaft 13 and the X-axis linear motion mechanism 16 and Y.
The swing motion of the swivel shaft 13 in the XY plane is connected between the shaft linear motion mechanism 17 and the X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism.
It comprises a displacement amount transmitting diaphragm 20 for transmitting to the displacement amount 17.

<Operation> In the above problem solving means, the swivel shaft 13 freely swivels in the XY axis plane with the pivot 22 as a fulcrum.

When the measuring needle 12 is displaced, the swivel shaft 13 swivels around the pivot 22, and the upper diaphragm attachment position of the swivel shaft 13 is displaced at a ratio (b / a) proportional to the vertical length. Due to its nature, the diaphragm 20 has low rigidity in the film thickness direction and very high rigidity in the direction perpendicular to the film thickness, so that the displacement in the X-Y axis plane can be accurately performed in the X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism 17. Tell.

In the X-axis translation mechanism 16 and the Y-axis translation mechanism 17, the parallel leaf spring 3
1,32,38,39 are deflected, and the reaction force becomes the measurement pressure. Also,
The displacement amount is detected by the X-axis and Y-axis detectors (digital linear scale or differential transducer) and becomes the displacement amount in the X-Y axis direction.

The height change due to the turning of the turning shaft 13 and the height change due to the displacement of the X-axis translation mechanism 16 and the Y-axis translation mechanism 17 are flexibly absorbed by the diaphragm 20 as shown in FIG.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of a tracer head showing an embodiment of the present invention, FIGS. 2 (a) and 2 (b) are detailed front views and perspective views of a diaphragm part, and FIG. 3 is a longitudinal sectional view of the tracer head. , FIG. 4 is a perspective view of the X-axis translation mechanism.

As shown in the figure, the tracer head according to the present invention is for displacement detection having a measuring needle 12 which is supported by a tracer head main body 11 so as to be capable of pivoting movement in an XY plane and which is movable in an axial direction (Z-axis direction). The swivel shaft 13, the Z-axis displacement mechanism 14 provided on the swivel shaft 13, and Z for detecting the displacement amount of the Z-axis displacement mechanism 14.
The axis detector 15, the Z-axis damper 36, and the X-axis direct-acting mechanism 16 and the Y-axis direct-acting mechanism 16 provided in the main body 11 for converting the turning motion of the turning shaft 13 into a linear motion component in the X-axis direction and the Y-axis direction. Dynamic mechanism
17, an X-axis detector 18 that detects the amount of displacement of the X-axis linear motion mechanism 16, a Y-axis detector 19 that detects the amount of displacement of the Y-axis linear motion mechanism 17, an X-axis damper 46, and a Y-axis. The damper 47 and the swivel shaft
Is connected between the upper end of 13 and the Y-axis translation mechanism 17 for transmitting the pivoting motion of the pivot shaft 13 in the XY plane to the X-axis translation mechanism 16 and the Y-axis translation mechanism 17. Displacement transmission diaphragm
It is composed of 20 and.

The swivel shaft 13 is formed in a tubular shape, and an upper portion thereof is incorporated in the main body 11 of the tubular body, and a lower portion thereof projects downward from the tracer head main body 11. The pivot shaft 13 is supported by the inner flange 21 at the lower end of the main body 11 by the pivot 22 so as to be pivotable in the XY plane at the position of the length ratio a / b. Further, a measuring needle 12 is fitted into the lower end of the swivel shaft 13 so as to be able to move back and forth along the axial direction thereof, and the measuring needle 12 is fitted on the upper part of the swivel shaft 13.
The Z-axis displacement mechanism 14 connected to is internally fitted. In addition,
Reference numeral 23 in the drawing denotes a measuring needle self-weight adjusting ring attached to the swivel shaft 13, and a spring 25 is stretched between the ring 23 and a flange 24 of the main shaft 48. Reference numeral 26 is a spring stretched between the lower end of the rotary shaft 13 and the lower end of the main shaft 48. The Z-axis contact pressure is generated by the two compression springs. A Z-axis guide bearing 28 guides the movement of the main shaft 48 in the axial direction (Z direction). The main shaft 48 has the measuring needle fixed at the lower end, and the Z-axis detector 15 is provided at the upper end. A Z-axis damper 36 is provided on the upper end of the Z-axis detector 15.

The X-axis direct-acting mechanism 16 includes an intermediate movable member 30 disposed below the upper end of the main body 11 by an upper support member 29 and shared with the Y-axis direct-acting mechanism 17, and the upper support member 29 and the intermediate movable member 30. It is composed of a pair of parallel leaf springs 31 and 32 on each of the front and rear surfaces which are fixed in a bridging manner.

The X-axis detector 18 for converting the displacement of the intermediate movable member 30 in the X-axis direction into an electric signal includes a rigid X-axis supporting rod 33 protruding downward from the upper supporting member 29 and an X-axis supporting rod 33. And an X-axis detection head 35 fixed to the intermediate movable member 30, and is configured to detect relative displacement of the upper support member 29 and the intermediate movable member 30 in the X-axis direction. It

The measuring pressure in the X-axis direction at the tip of the measuring needle 12 is generated by the reaction force due to the bending of the parallel leaf springs 31 and 32. Therefore, the parallel leaf springs 31 and 32 are arranged such that the plate thickness direction thereof is the X-axis direction. The X-axis damper 46 has one end fixed to the X-axis support rod 33 and the other end fixed to the intermediate movable member 30 so as to absorb the vibration of the X-axis translation mechanism 16.

The Y-axis translation mechanism 17 includes the intermediate movable member 30, a lower movable member 37 connected to the diaphragm 20 at a position below the intermediate movable member 30, and a difference between the lower movable member 37 and the intermediate movable member 30. It is composed of a pair of parallel leaf springs 38, 39 on each of the left and right surfaces which are fixed in a fixed manner.

The Y-axis detector 19 for converting the displacement of the lower movable member 37 in the Y-axis direction into an electric signal includes a rigid Y-axis support rod 41 projecting upward from the lower movable member 37 and the support rod 41. Fixed Y
It is composed of an axis detector 42 and a Y-axis detection head 43 fixed to the intermediate movable member 30, and is configured to detect the relative displacement of the intermediate movable member 30 and the lower movable member 37 in the Y-axis direction.

The measurement pressure in the Y-axis direction at the tip of the measuring needle 12 is generated by the reaction force due to the bending of the parallel leaf springs 38, 39. Therefore, the parallel leaf springs 38, 39 are arranged such that the plate thickness direction thereof is the Y-axis direction. The Y-axis damper 47 has one end fixed to the Y-axis support rod 41 and the other end fixed to the intermediate movable member 30, and absorbs the vibration of the Y-axis translation mechanism.

As shown in FIG. 2 (b), the diaphragm 20 is made of, for example, a disk-shaped thin leaf spring, and its front and rear ends are at the upper end of the swivel shaft 13.
The pair of front and rear mounting pieces 45 protruding downward from the diaphragm 20 fixes the left and right ends to the lower end of the lower movable member 37 by the pair of left and right mounting pieces 27 protruding upward from the diaphragm 20. The line segment connecting the pair of front and rear mounting pieces 45 and the line segment connecting the pair of left and right mounting pieces 27 are orthogonal to each other.
7,45 are arranged.

In the above structure, the swivel shaft 13 freely swivels in the XY plane with the pivot 22 as a fulcrum.

When the measuring needle is displaced, the swivel shaft 13 swivels around the pivot 22, and the swivel shaft 1 moves at a ratio (b / a) proportional to the vertical length.
The upper diaphragm attachment position of 3 is displaced. Due to its nature, the diaphragm 20 has low rigidity in the film thickness direction and very high rigidity in the direction perpendicular to the film thickness, so that the displacement in the X-Y axis plane can be accurately performed in the X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism 17. Tell.

In the X-axis translation mechanism 16 and the Y-axis translation mechanism 17, the parallel leaf spring 3
1, 32, 38, 39 are deflected, and the reaction force generates the measurement pressure of the measurement needle 12. Further, the displacement amount is detected by the X-axis and Y-axis detectors (digital linear case or differential transducer) and becomes the displacement amount in the X-Y axis direction.

The X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism 17 are arranged at right angles, and X,
Since the displacement spring constant in the Y direction is the same, the X-
The displacement vector in the Y plane can be accurately decomposed into X and Y displacement components.

The height change due to the turning of the turning shaft and the height change h due to the displacement of the X-axis linear motion mechanism 16 and the Y-axis linear motion mechanism 17 are absorbed by the diaphragm 20 as shown in FIG. 2 (a). It

The parallel leaf springs 31, 32, 38, 39 have low rigidity in the plate thickness direction, but have extremely high rigidity in the direction perpendicular to the plate thickness direction. Therefore, displacement of the lower movable member 37 causes the Y-axis translation mechanism 17 to move. Parallel leaf springs 38,3
9 bends only in the Y-axis direction and transmits the X-displacement directly to the intermediate movable member 30 without bending in the X-axis direction. Similarly, the parallel leaf springs 31 and 32 of the X-axis translation mechanism 16 bend only in the X-axis direction and do not bend in the Y-axis direction. Axial displacement and Y
Axial displacement can be detected.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention. For example, the diaphragm 20 is not limited to the thin leaf spring as in the above embodiment, but may be a diaphragm, a membrane plate, or the like.

<Effects of the Invention> As is clear from the above description, in the present invention, the swivel shaft freely swivels in the XY axis plane with the pivot as the fulcrum, the diaphragm mounting position of the swivel shaft is displaced, and the X film is moved by the diaphragm. −
Since the displacement in the Y-axis plane is accurately transmitted to the X-axis linear motion mechanism and the Y-axis linear motion mechanism, it is possible to perform motion conversion without friction and without backlash, the structure is simple, and the large displacement does not depend on the detector. It is possible to provide a tracer head. Further, if the change in the height direction due to the turning motion of the turning shaft can be absorbed by the deflection of the diaphragm such as the thin leaf spring, it is possible to obtain an excellent effect.

[Brief description of drawings]

FIG. 1 is a perspective view of a tracer head showing an embodiment of the present invention, FIGS. 2 (a) and 2 (b) are detailed front views and perspective views of a diaphragm part, and FIG. 3 is a longitudinal sectional view of the tracer head. , 4th
FIG. 5 is a perspective view of an X-axis linear motion mechanism, FIG. 5 is a perspective view of a tracer head having a Z-axis turning motion and a uniaxial rectilinear shaft, and FIG. 6 is a perspective view of a tracer head having a triaxial rectilinear shaft. FIG. 8 is a perspective view of a first tracer head having a conventional swivel axis, FIG. 8 is a side view of a second tracer head having a conventional swivel axis, FIG. 9 is a front sectional view of the same, and FIG. FIG. 9 is a front cross-sectional view of a third tracer head having the pivot axis of FIG. 11 …… Main body, 12 …… Measurement needle, 13 …… Swivel axis, 14 …… Z-axis displacement mechanism, 15 …… Z-axis detector, 16 …… X-axis translation mechanism, 17
...... Y-axis linear motion mechanism, 18 ... X-axis detector, 19 ... Y-axis detector, 20 ... diaphragm.

Claims (1)

[Claims] 1. A displacement detecting swivel shaft having a measuring needle at its lower end, which is supported by a tracer head body so as to swivel in an XY plane, a Z-axis displacement mechanism provided on the swivel shaft, and the Z-axis. A Z-axis detector for detecting the amount of displacement of the displacement mechanism, an X-axis linear motion mechanism and a Y-axis linear motion provided in the main body for converting the rotary motion of the rotary shaft into a linear motion component in the X-axis direction and the Y-axis direction. Mechanism, an X-axis detector that detects the amount of displacement of the X-axis direct-acting mechanism, a Y-axis detector that detects the amount of displacement of the Y-axis direct-acting mechanism, an upper end of the swing shaft, and the X-axis direct-acting. A displacement amount transmitting diaphragm that is connected between the mechanism and the Y-axis direct-acting mechanism to transmit the swivel motion of the swivel axis in the XY plane to the X-axis direct-acting mechanism and the Y-axis direct-acting mechanism. A tracer head characterized by comprising.