JPH02256408A - Three-dimensional machine - Google Patents

Abstract

PURPOSE:To achieve ease of three-dimensional machining by providing a working tool with a concavely curved surface at its rotating central portion between multiple cutting portions which are provided at the tip of a shaft and are roughly spherical in shape, and inclining it in a three-dimensional direction at its rotating center. CONSTITUTION:A working tool 12 is employed which is provided with multiple cutting portions 14, 15, roughly spherical in shape, at the tip of its shaft portion 13 that is driven rotatingly and which is additionally provided with a concave portion 16 on the periphery of the rotating center 17 between these cutting portions 14, 15. In this manner, cutting can be performed on the outer periphery of the cutting portions 14, 15 which provide cutting speed while the rotating center 17 is kept perpendicular with respect to the work to be cut, and the cutting of three-dimensional convex surfaces is possible because of the concaved portion 16. Thus, by inclining the working tool 12 in a three-dimensional direction around its tip by means of an inclining means, it is possible to perform three-dimensional machining with the rotating center of the tool 12 always kept perpendicular to the surface of the work.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention performs cutting or grinding by rotating a tool such as a milling cutter or drill, and moves the workpiece only in relation to the tool. The present invention relates to a three-dimensional processing machine that can produce an excellent finished surface with a small number of man-hours.

(Prior Art) The most typical model of this type of processing machine is generally called a machining center, in which the positional relationship between a rotating tool and a workpiece is controlled by a co/viewer.

In order to explain the functions of this machining center, we will take as an example the machining of three-dimensional solid objects, which is its most typical type of machining.

When performing three-dimensional processing using this machining center,
A ball end mill is usually used as a tool.

As shown in FIG. 2, the rotation center 3 of this ball end mill 1 is vertical as shown at normal position a.

Therefore, the rotation center 3 of the ball end mill 1 comes into contact with the workpiece 2.

Since the cutting speed at this center of rotation 6 is zero, the cutting force is small and it is necessary to perform cutting while making small feeds, which results in extremely inefficient machining. Therefore, it is more efficient to tilt the rotation center 6 of the ball end mill 1 at a certain angle as shown in FIG. 2 and perform machining at a portion where the rotation radius is large, that is, a portion where the cutting speed is high.

Therefore, processing machines such as the above-mentioned machining centers have been developed in which a fourth-dimensional adjustment function is added to the supporting portion of the ball end mill 1 so that the ball end mill 1 can be oscillated in order to change its angle.

When finishing cutting a concave curved surface such as the workpiece 2 shown in FIG. When the position C is reached, the rotation center 6 becomes perpendicular to the workpiece 2 again and the cutting speed is lost.

Therefore, at this point, the angle of the ball end mill 1 is changed again to make corrections so that the center of rotation 6 is at position d, and cutting is performed while repeating such corrections.

(Problem to be Solved by the Invention) As mentioned above, even if the angle of the conventional ball end mill 1 is finely corrected (support), the machined surface has a reciprocating feed value pitch as shown in Fig. 3. The waveform was a series of circular arcs, and it was not possible to obtain a smooth surface.

Therefore, in order to obtain an even smoother surface, it was necessary to perform a flattening process such that the cutting marks on the end face of the milling cutter as shown in FIG. 4 cross each other. Furthermore, as shown in FIGS. 5(A) and 5(B), in many cases where the tool is tilted, the center of oscillation rotation 4 is at the center of the main shaft 5. In this case, the tip of the tool is The portion 6 will be offset vertically by a distance and horizontally by a distance.

Therefore, it was necessary to add an offset correction movement in any two of the basic movement directions, x and ySz directions.

In order to avoid this correction, it is possible to give an inclination in advance around the machining part. For example, as shown in FIG. A structure in which the arm 9 is tilted at 45 degrees with respect to the arm 7 and is rotatable is double-combined.

This structure is compact and rigid enough to manually apply the tool tip to the workpiece at an appropriate angle by visual inspection, but it is very suitable for fully automatic NC. There are some weaknesses.

That is, if additional mechanisms such as automatic NC of each rotation axis 10.11 of arm 7.9, axial direction feed of the tool, and automatic tool change mechanism are added, the structure becomes large, and in particular, the structure of arm 7.9 becomes larger.
An interference relationship occurs between the tool 9 and the workpiece, which significantly limits the processing movement range.

In addition, a three-dimensional curved surface is usually specified by data given as design values or shape data measured by a three-dimensional measuring device, and this data is defined in two directions at regular intervals on the X-Y plane. given as a numerical value of °
It is customary to do so.

In this case, in order to calculate from this value the angle at which the rotational axis of the tool perpendicular to the curved surface is tilted, extremely complicated conversion calculations are required.

Of course, it is possible to input this calculation formula into computer software and perform it automatically, but the part required for this calculation alone takes up a considerable portion of the computer's capacity, and furthermore, the calculation time becomes longer, making processing more difficult. It becomes impossible to follow the rapid movement of the feed.

In order to increase this calculation speed, it is necessary to use a higher capacity and faster computer.
This will lead to higher prices.

Furthermore, when making minute corrections to a machined surface, it is easiest for humans to determine the correction value from the three-dimensional x, y, and z positions and the feed in the axial direction of the processing axis.

That is, it is easiest to add correction values one by one to a certain value.

However, in the triple arm structure described above, a corrective action given to one part will affect the numerical values of all other movable mechanisms, and multiple movable mechanisms must be made to move in a complex manner. , which required more complex calculations.

Especially around the highest apex, even a slight angular change that exceeds this apex must cause a large rotational angle change to each rotation axis to synthesize the small angular changes, and this is the most frequently used angle operation. It has the most disadvantageous drawback.

Therefore, in practice, it is necessary to use only a few points with large angle changes prepared in advance, such as the example shown in FIG. 2, and it is almost impossible to use the topmost portion.

SUMMARY OF THE INVENTION An object of the present invention is to provide a three-dimensional processing machine that solves the above problems of the conventional example with a simpler mechanism and enables automatic CNC processing using simple software.

(Means for Solving the Problem) The three-dimensional processing machine of the present invention includes a shaft portion, a plurality of approximately spherical cutting portions provided at the tip of the shaft portion, and a rotation center portion between the cutting portions. The present invention includes a machining tool including a concave curved surface portion provided on the machining tool, and a tilting mechanism that tilts the center of rotation of the machining tool in a three-dimensional direction around its tip.

(Function) The processing tool of the present invention is provided with a concave curved surface portion at the center of rotation where the cutting speed is zero.

Therefore, even if the machining tool is brought into contact with the rotation center perpendicular to the workpiece, the outer periphery of the cutting part that has the cutting speed will come into contact with the workpiece. .

Moreover, the concave curved surface part can also be used to cut the convex surface of a three-dimensional solid, and by tilting such a processing tool in a three-dimensional direction with its tip as the center using a tilting means,
Cutting is performed by keeping the center of rotation of the processing tool perpendicularly in contact with the surface of the workpiece.

In this way, it is possible to use a machining tool that can cut even if it is brought into contact with the workpiece in a perpendicular state, and furthermore, it is possible to tilt the machining tool without having to correct positional deviations due to angle changes using the X5YSz axes. By using a tilting mechanism, the machining tool can always be perpendicularly applied to a three-dimensional curved surface, and its position can be easily controlled.

(Example) The present invention will be described in detail below based on the drawings.

FIG. 1 and FIG. 7 are diagrams showing a processing tool of a processing machine according to an embodiment of the present invention.

This processing tool 12 has a shaft section 13 that is rotationally driven by a rotational drive section of the processing machine main body, a cutting section 14, 15 that is approximately spherical in shape provided at the tip of this shaft section 16, and a section between the cutting section. As shown in FIG. 1, this machining tool 12 is composed of a concave curved surface section 16 provided around a rotation center 17, and is positioned perpendicularly to the surface of the workpiece. The cutting part 1 rotates by moving while maintaining the
Cutting is performed using the outer circumference of 4.15 mm.
Further, as shown in FIG. 7, by using the concave curved surface portion 16, it is possible to perform circular cutting to the tip of a sharp convex shape.

FIG. 8 is a diagram showing a tilting mechanism of a processing tool in a processing machine according to an embodiment of the present invention.

This tilting mechanism, in the xSy,z three-dimensional space shown in the figure,
Axis 0 in the X direction passing through point P where the tip of the processing tool 12 is located
A second arm 19 is attached to the tip of the shaft-shaped first arm 18 that rotates around the point 01, and the second arm 19 is capable of changing the corner with respect to the side R1L in a plane including the plane 0RLP with this point as the center. A sixth arm 20 is attached to the tip and moves parallel to the axis OR in a plane centered on this point M and includes the plane 0RLP, and is further attached to its end and always moves in a plane centered on this point N and including the plane 0RLP. - It has a fourth arm 21 that moves parallel to the IJIJ2 arm 19.

The processing tool 12 is attached to the fourth arm 21 so that its center of rotation passes through the point P.

Also, the XSY of the tip of the processing tool 12 at point P.

Movement in the Z direction is similar to normal three-dimensional processing machines, such as XSY,
This is done using a Z slide (not shown) and its numerical value feed mechanism.

According to such a tilting mechanism shown in FIG. 8, the first arm 18 is pivoted, and the second, sixth, and fourth arms 19 are
．． 20 and 21, the inclination of the rotation center of the processing tool 12 can be changed without changing the position of the point P.

Therefore, while changing the inclination of the machining tool,
By moving the workpiece by driving the Z slide with a numerical feed mechanism, it is possible to easily cut any three-dimensional shape.

Next, the drive mechanism of each arm shown in FIG. 8 will be explained.
FIG. 9 is a diagram showing a drive mechanism for the first arm 18 shown in FIG. 8.

This drive mechanism includes a worm wheel 22 attached with its axis aligned with the axis OO1, an actuator 26 in an external structure provided on a sleeve (not shown) that rotatably holds the axis OO. , and a worm 24 driven thereby.

In this drive mechanism, when the worm wheel 22 is rotated by the worm 24, the first arm 18 is moved toward the axis 00'.
Rotate around the center of rotation.

The rotation angle of the first arm 18 and the rotation speed of the actuator 26 maintain a linear relationship. FIG. 10 is a diagram showing the drive mechanism of the second arm 19 shown in FIG. 8.

This drive mechanism includes a worm wheel 25 that is concentric with the rotation axis of the second arm 19 and integrated with the second arm 19, and an actuator 26 that is attached to the axes R and L of the first arm 18. The worm 27 is driven by the worm 27.

In this drive mechanism, when the worm wheel 25 is rotated by the worm 27, the worm wheel 25 is rotated by the worm 27.
5, the second arm 19 rotates.

Also in this mechanism, the rotation angle of the second arm 19 maintains a linear relationship with the rotation speed of the actuator 26.

FIG. 11 is a diagram showing a drive mechanism for the sixth arm 20 shown in FIG. 8.

This third arm 20 is always aligned with the axis OR of the first arm 18.
move parallel to.

In order to obtain this operation, as shown in the figure, a gear 28 integrated with the axis RL of the first arm with the dot as the center, an idle gear 29 on the second arm 19 meshing with this, and an idle gear 29 on the second arm 19 that meshes with the gear 28, The sixth arm 20 is rotated by a gear 30 that is engaged with the gear 30 and is fixed to the sixth arm 20 with the point M closed in the middle.

That is, in this gear train, the gears 28 and 30 are set to always maintain the same phase, and therefore the third arm 2
The direction of 0 is always kept constant regardless of the movement of the second arm 19.

FIG. 12 is a diagram showing a drive mechanism for the fourth arm 21 shown in FIG. 8.

This fourth arm 21 is always kept parallel to the second arm 19.

The drive mechanism that maintains the parallelism in this way consists of a sprocket 61 fixed to the sixth arm 20, a tin rocket 32 of the same diameter fixed to the fourth arm 21, and a sprocket 32 fixed to the fourth arm 21.
1.32 and a chain 66 connecting the two.

Since these sprockets 31 and 32 are connected by a chain 66, they are in the same phase, and the second arm 19 and the fourth
Arms 21 are kept parallel.

Instead of this sprocket, etc., it is also possible to use a gear train consisting of an odd number of gears.

The drive mechanism for each arm described above allows the rotation speed of the actuator and the movement of each arm to be driven in a simple proportional relationship. It can be tilted to this position.

On the other hand, weight, force applied during machining, etc. are constantly applied to each rotating arm in a variable manner.

Therefore, backlash between the worm and the worm wheel, the gear train, the sprocket, the chain, etc. is biased in the opposite direction, which may cause problems such as a decrease in accuracy and an increase in vibration.

For this reason, it is important to eliminate backlash.
FIGS. 13A, 13B, and 13C show common basic structures for eliminating backlash.

FIG. 13(A) shows the worm wheel 64 and the worm 3.
5. Fig. 13 (B) shows a gear train consisting of three gears 66, 67, 58, and Fig. 13 (C) shows a sprocket 40.
．． 42 and the chain 46 are shown.

What they all have in common is the distance between the axes of the worm 65 and the worm wheel 64, and the distance between the axes of the idle gear 37 and the center line of the in-phase gear 3 (5, 38, sprocket) 40. Connecting each axis of 42 For each axis distance of the chain tension roller 41 in the line direction, F
Pressure is applied with a spring in the direction to absorb minute movements due to component errors, and crimping is performed to eliminate backlash.

If some abnormal force is applied and the reverse direction is greater than the spring pressure, a stopper 44 is provided to stop the reverse movement at the furthest position within the normal range of variation, and the stopper is used instead of the spring pressure to maintain the fixed state. and hold the position.

Steel belts, wire ropes, etc. may be used instead of chains.

Further, a composite structure is also possible that uses the tension of this belt to eliminate backlash in the gear train drive.

By adding a mechanism for moving the machining tool 12 in the direction of the rotation axis, the position of the point P relative to the outer diameter of the cutting part can be finely adjusted to the most desirable position as shown in positions C, 2, and E shown in FIG. becomes possible.

It is, of course, desirable to place this movement mechanism under NC control, and with this structure, it is possible to perform slight polling, make slight modifications to the curved surface shape, add variations by subtle design changes, process small convex spherical or concave surfaces by rotating the arm, and process cylindrical surfaces. It becomes possible to process the surface completely separately from other x, y, z positions and inclination angles.

(Effects of the Invention) According to the present invention, the processing tool is moved 900 degrees in each direction around the vertical axis.
It is possible to position it arbitrarily and near IJ within the solid angle of the hemisphere, and it is possible to smoothly finish a three-dimensional curved surface with a simpler structure and without complicating computer software.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a cutting state by a processing tool of a three-dimensional processing machine according to an embodiment of the present invention, Fig. 2 is a diagram showing a cutting state by a conventional ball end mill, and Fig. 3 is a diagram shown in Fig. 2. A diagram showing a curved surface cut by a ball end mill. Figure 4 is a diagram showing an example of finishing machining of the curved surface shown in Figure 3. Figures 5 (A) and (B) are tilted states of the processing tool in a conventional processing machine. FIG. 6 is a diagram showing an example of improving the drawbacks of the processing machine shown in FIG. 8 is a diagram showing a tilting mechanism of a three-dimensional processing machine according to an embodiment of the present invention, FIG. 9 is a diagram showing a drive mechanism of the first arm shown in FIG. 8, and FIG. FIG. 11 is a diagram showing the drive mechanism of the sixth arm shown in FIG. 8. FIG. 12 is a diagram showing the drive mechanism of the fourth arm shown in FIG. , FIGS. 13(A), 13(B), and 13(C) are diagrams showing a mechanism for eliminating backlash in the drive mechanism of each arm. 12... Processing tool, 16... Shaft part, 14.15...
・Cutting part, 16... Concave curved surface part, 17... Center of rotation,
18... 1st arm 19... 2nd arm, 20...
・6th arm, 21...4th arm. Figure 3 Figure 4

Claims (3)

[Claims] (1) A processing tool consisting of a shaft portion, a plurality of approximately spherical cutting portions provided at the tip of the shaft portion, and a concave curved surface portion provided at the center of rotation between the cutting portions; A three-dimensional processing machine comprising: a tilting mechanism that tilts the center of rotation of a processing tool in a three-dimensional direction with its tip as the center; (2) comprising: a shaft; a plurality of substantially spherical cutting parts provided at the tip of the shaft; and a concave curved part provided at the center of rotation between the cutting parts. processing tools. (3) A processing tool having a shaft portion, a plurality of approximately spherical cutting portions provided at the tip of the shaft portion, and a concave curved surface portion provided at the center of rotation between the cutting portions. It is characterized by cutting by tilting the center of rotation in a three-dimensional direction around its tip, keeping the center of rotation perpendicular to the workpiece, and then moving the workpiece in the processing direction. A processing method using a three-dimensional processing machine.