HK1232829A1 - Cutting method for inner circumferential face or outer circumferential face of work - Google Patents

Description

Cutting method for inner peripheral surface or outer peripheral surface of workpiece

Technical Field

The present invention relates to a cutting method for an inner peripheral surface and an outer peripheral surface of a workpiece by keeping a cutting speed constant in cutting by a cutting tool of a spindle that rotates (revolves) around a predetermined position and whose radius of the rotation is adjustable.

The "turning (revolving) of the spindle" includes not the rotation along the central axis of the spindle itself but the revolution around the predetermined position.

Background

As a method of forming the inner peripheral surface and the outer peripheral surface of the workpiece into curved surfaces formed in various shapes such as a cylindrical shape, a tapered shape, a flange shape, and the like, there is a technical advantage in that, in the case of this machining method, machining can be performed regardless of the position of a table supporting the workpiece by adopting so-called orbital (orbit) machining in which a spindle revolves around a predetermined revolution center, as shown in patent document 1.

However, in order to make the cutting surface uniform, the cutting speed is required to be constant.

However, in the above-described conventional raceway machining method, a configuration in which the cutting speed is constant is not adopted.

Patent document 2 discloses a structure required to ensure a constant cutting speed from a cutting start end to a cutting end in a gear shape machining method.

However, patent document 2 only describes that the cutting speed is made constant only by the control of the NC lathe, and does not make any explicit mention as to what kind of reference the cutting speed is made constant qualitatively or quantitatively.

Patent document 3 discloses that a constant cutting speed is obtained by controlling the spindle rotation speed by CAM, but patent document 3 does not show any concrete configuration in which the cutting speed is made constant by any reference.

In addition, in both patent documents 2 and 3, cutting by rotation along the central axis of the spindle itself is assumed, and in the case where the spindle revolves around a predetermined position as in the present invention, the cutting speed is made constant, which is not disclosed or suggested at all.

As described above, a cutting method of controlling the cutting speed of the cutting tool to be constant in the cutting process of the inner surface or the outer surface of the workpiece by the rotation of the spindle has not been proposed so far.

Patent document 4 discloses that when the rotational angular velocity of the spindle is ω, the distance from the center of rotation to the tip of the cutting tool is R, and a constant amount C is set as the cutting speed at the tip of the cutting tool, the cutting speed of the cutting tool is made constant by controlling ω to vary in accordance with the variation of the distance R (paragraph 0040 and fig. 7(a), (b)).

However, the constant cutting speed in patent document 4 is merely a state in which R · ω is constant, and there is no disclosure that a constant cutting speed is ensured when the temporal change rate of the distance R is also a factor.

In this sense, patent document 4 does not absolutely set the cutting state to be exactly constant.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 8-126938

Patent document 2: japanese patent laid-open No. 2000-190127

Patent document 3: japanese patent laid-open publication No. 2001-113443

Patent document 4: japanese patent laid-open publication No. 2011-131324

Disclosure of Invention

Problems to be solved by the invention

The present invention has an object to provide a cutting method capable of accurately performing control such that a cutting speed is constant in cutting an inner peripheral surface or an outer peripheral surface of a workpiece based on rotation of a spindle about a predetermined position.

Means for solving the problems

In order to solve the problems, the basic constitution of the present invention includes:

(1) a method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece by a cutting tool protruding from a spindle that revolves around a predetermined position and whose radius of the revolution is adjustable, wherein when a revolution angular velocity of the spindle is represented by ω, a distance from the center of the revolution to a tip end of the cutting tool is represented by R, and a constant value C is set as a cutting speed at the tip end of the cutting tool, the cutting speed of the cutting tool is made constant by controlling so that ω changes in accordance with a change in the distance R and the following equation 1 is satisfied,

formula 1:

wherein the content of the first and second substances,represents the time differential of said distance R;

(2) the method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to the above (1), wherein when the workpiece is placed on the table, a center position of a revolution of the spindle is made movable in a direction orthogonal to or in an oblique direction with respect to a plane orthogonal to a center axis of the revolution, and when the workpiece is movable in the oblique direction, the table is moved in the direction of the plane in accordance with the movement, whereby a support position of the workpiece on the table is set so that a cutting position of the workpiece is at the distance R from the center position of the revolution of the spindle, and a state in which cutting is possible is maintained;

(3) the method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to the above (1), wherein when the workpiece is placed on a table rotatable on a table of a machining center, the center position of the revolution of the spindle is set to be movable in a direction orthogonal to or in an oblique direction with respect to a plane orthogonal to the center axis of the revolution, and when the table is movable in the oblique direction, the table is moved in the direction of the plane in accordance with the movement, whereby the support position of the table with respect to the workpiece on the table is set so that the center position of the rotation of the spindle is set to be the distance R from the cutting position of the workpiece, and the cutting-enabled state is maintained, the machining center being a machining center that performs not only cutting but also other machining of the workpiece;

(4) the method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to the above (1), wherein when a workpiece is gripped by an arm of a robot, a center position of a revolution of a spindle is set to be movable in a direction orthogonal to or in an oblique direction with respect to a plane orthogonal to a center axis of the revolution, and when the workpiece is movable in the oblique direction, the arm is moved in the direction of the plane in accordance with the movement, whereby a position gripped by the arm is set to be a position where a cutting position of the workpiece is at the distance R from the center position of the revolution of the spindle, and a state where cutting is possible is maintained.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, the basic configuration (1) can ensure a uniform cutting surface by keeping the cutting speed constant, while the basic configuration (2), the basic configuration (3), and the basic configuration (4) can form the inner surface or the outer surface of the workpiece into various curved surfaces.

That is, as shown in patent documents 2 and 3, it is not necessary to perform complicated calculation or operation control.

Drawings

Fig. 1 is a block diagram relating to a system for implementing the method of the present invention, (a) shows an embodiment in which a workpiece is mounted on a table, and (b) shows an embodiment in which a workpiece is mounted on a table of a machining center via a rotatable table.

Fig. 2 is a plan view showing a planar state in a direction perpendicular to a central axis of revolution of the main shaft, (a) shows a case of cutting the inner peripheral surface, and (b) shows a case of cutting the outer peripheral surface.

Fig. 3 shows a method of forming a normal tapered shape by moving the center position of the revolution of the spindle and gradually changing the radius of the revolution, (a) is a plan view showing a movement locus at the tip end of the cutting tool, and (b) is a side view showing a tapered shape formed by the gradual change.

Fig. 4 shows a method of forming a stepwise tapered surface by moving the center position of the revolution of the spindle and changing the radius of the revolution stepwise, where (a) is a plan view showing the movement locus at the tip of the cutting tool, and (b) is a side view showing the stepwise tapered surface formed by the stepwise change.

Fig. 5 is a perspective view showing a process of forming an annular shape by spirally moving the tip of the cutting tool in the inner region and the outer region of the workpiece and finally moving the tip in a circular shape without moving the center position of the rotation of the spindle, (a) shows a process of forming an inner wall of the annular shape, (b) shows a process of forming an outer wall of the annular shape, and (c) shows the annular shape finally formed.

Description of the reference numerals

1 spindle

2 cutting tool

3 workpiece

4 working table

40 working part for performing work other than cutting on a workpiece in a machining center

41 platform of machining center

5 control device

6 centre axis of revolution or centre axis of rotation

Detailed Description

As shown in fig. 1(a) and (b), the present invention is configured with a revolving spindle 1, a cutting tool 2 provided on the tip side of the spindle 1, a workpiece 3, a table 4 (in the case of fig. 1 (a)) for supporting the workpiece 3, the table 4 for supporting the workpiece 3, and a table 41 on which a machining center of the table 4 is placed, or an arm (not shown) of a robot for gripping the workpiece 3, and a control device 5 for controlling the spindle 1 and the table 4, the table 41 (in the case of fig. 1 (b)), or the movement of the arm of the robot.

In fig. 1(a) and (b), the open arrows indicate the movement of the spindle 1 in accordance with the turning radius adjustment and the movement state in the orthogonal direction or the oblique direction, the curved arrows indicate the turning state of the spindle 1, the broken-line arrows extending from the control device 5 indicate the transmission state of the signal for controlling the turning angular velocity, the solid arrows indicate the transmission states of signals for controlling the movement of the table 4, the table 41, or the rotation center of the arm of the robot corresponding to the movement of the center of the spin of the spindle 1 in the above-described oblique direction, and the movement of the spindle 1 in accordance with the adjustment of the radius of the spin, and the movement of the center of the spin of the spindle 1 in the above-described orthogonal direction or the oblique direction in the above-described basic configuration (2), the basic configuration (3), and the basic configuration (4).

In the present invention, the main factors to be controlled are parameters such as the rotational angular velocity of the main shaft 1 with respect to the center of the revolution, the radius of the revolution of the main shaft 1 (in the case of the basic configuration (1) above), and the position or the moving speed at which the center of the revolution moves in the direction orthogonal or oblique to the plane orthogonal to the revolution center axis 6 of the main shaft 1 (in the case of the basic configuration (2), the basic configuration (3), and the basic configuration (4) above), two parameters in the case of the basic configuration (1), and three parameters in the case of the basic configuration (2), the basic configuration (3), and the basic configuration (4).

The spindle 1 and the cutting tool 2 are rotated at a predetermined center position, and the tip of the cutting tool 2 cuts the inner peripheral surface of the workpiece 3 as shown in fig. 2(a) or the outer peripheral surface of the workpiece 3 as shown in fig. 2(b), but since the radius of rotation of the spindle 1 from the center position is freely adjustable, the radius of curvature at the tip of the cutting tool 2 is also freely adjustable, and a curved surface to be cut can be arbitrarily selected.

That is, the circumferential curved surfaces in fig. 2(a) and (b) are merely typical examples, and the cutting curved surface is not limited to the circumferential curved surface at all.

The reference of the mathematical expression based on the basic configuration (1) corresponding to the technical requirement of making the cutting surface uniform will be described below.

As shown in fig. 2(a) and (b), when the radius of the tip of the cutting tool 2 is R, the angular position is θ, and the coordinate position is (X, Y), X ═ Rcos θ and Y ═ Rsin θ are satisfied, and the following equation 2 is satisfied,

formula 2:

in addition, a point indicated by "·" of each symbol represents time differentiation.

Therefore, when the cutting speed is V, the following expression 3 is established.

Formula 3:

according to the above relational expression, when the rotational angular velocity of the spindle 1 is ω 1 and the rotational angular velocity of the table 4 is ω 2, the distance R and the time derivative thereof are further differentiated when the constant amount C is set in advance so that the cutting speed V at the distal end of the cutting tool 2 is constantAccordingly, control is performed so that the following expression 4 is satisfied.

Formula 4:

in the present invention, in order to form the cutting shapes of the inner peripheral surface and the outer peripheral surface having various shapes, an embodiment of the basic configuration (2) may be adopted, as shown in fig. 1(a), wherein when the workpiece 3 is placed on the table 4, the center position of the revolution of the spindle 1 is made movable in a direction orthogonal to a plane orthogonal to the center axis 6 of the revolution or in an inclined direction, and when the workpiece 3 is movable in the inclined direction, the table 4 is moved in the direction of the plane in accordance with the movement, whereby the support position of the workpiece 3 on the table 4 is set so that the center position of the rotation of the spindle 1 is the cutting position of the workpiece 3 at the distance R from the cutting position of the workpiece 3 and the cutting state is maintained,

or, as shown in fig. 1(b), the embodiment of the basic configuration (3) is characterized in that, when the workpiece 3 is placed on the table 4 rotatable on the table 41 of the machining center, the center position of the revolution of the spindle 1 is made movable in a direction orthogonal to a plane orthogonal to the center axis 6 of the revolution or in an inclined direction, and when the table 41 is movable in the inclined direction, the table 41 is moved in the direction of the plane in accordance with the movement, whereby the support position of the table 4 on the table 41 for the workpiece 3 is set so that the cutting position of the workpiece 3 is at the distance R from the center position of the revolution of the spindle 1 and the cutting-enabled state is maintained,

alternatively, the embodiment of the basic configuration (4) is characterized in that, when the workpiece 3 is gripped by an arm of a robot (not shown), the center position of the revolution of the spindle 1 is made movable in a direction orthogonal to a plane orthogonal to the center axis 6 of the revolution or in an oblique direction, and when the workpiece 3 is movable in the oblique direction, the arm is moved in the direction of the plane in accordance with the movement, whereby the position gripped by the arm is set so that the center position of the rotation of the spindle 1 from the cutting position of the workpiece 3 is the distance R and the cutting-enabled state is maintained.

In the configuration of the basic configuration (2), the table 4 does not necessarily need to be rotatable, but in the case of the basic configuration (3), the table 4 needs to be rotatable in order to operate the working portion 40 that performs a work other than cutting of the workpiece 3.

As in the basic configuration (2), the basic configuration (3), and the basic configuration (4), when the center of the revolution of the spindle 1 is made movable in the oblique direction, since the center axis 6 of the revolution of the spindle 1 itself moves, it is preferable to move the position in the direction of the plane of the table 4 or the mounting table 41 (in the case of the basic configuration (2) or the basic configuration (3)) or the position in the direction of the plane of the arm (in the case of the basic configuration (4)) in synchronization with the center position of the revolution in order to maintain the cutting state of the cutting tool 2 with respect to the workpiece 3.

Fig. 3(a) and (b) show a case where an outer peripheral surface having a normal tapered shape is formed by an embodiment characterized in that the center position of the revolution of the main shaft 1 is moved in the orthogonal direction or the oblique direction, and the radius of the revolution is gradually changed.

In the case where both side ends of the tapered surface are formed as circumferential curved surfaces, as shown in fig. 3(a) and (b), the radius of the convolution may be substantially constant at the initial stage and the final stage of the convolution.

Fig. 4(a) and (b) show a case where a tapered inner peripheral surface is formed in a stepped state in an embodiment characterized in that the center position of the revolution of the spindle 1 is moved in the orthogonal direction or the oblique direction, and the radius of the revolution is changed stepwise.

As is clear from fig. 3(a) and (b) and fig. 4(a) and (b), in the basic configuration (2), the inner circumferential surface or the outer circumferential surface can be formed in various shapes.

In each of the above figures, although the center of the revolution of the main shaft 1 is moved in a direction perpendicular to a plane perpendicular to the center axis 6 of the revolution, that is, in the same direction as the center axis 6 of the revolution, even when the center is moved in an inclined direction inclined with respect to the plane, a tapered shape in which the overall shape changes in the inclined direction can be obtained.

Unlike the embodiments shown in fig. 3(a) and (b) and fig. 4(a) and (b), an inner peripheral surface or an outer peripheral surface (not shown) of a normal cylindrical shape (here, a case where the center of the revolution moves in the orthogonal direction) or an inclined direction cylindrical shape (here, a case where the center of the revolution moves in the inclined direction) can be obtained without changing the radius of the revolution of the main shaft 1.

Fig. 5 shows an embodiment with the following features: the center position of the revolution of the spindle 1 is not moved in the orthogonal direction or the oblique direction, but

(1) In the inner region of the workpiece 3 near the center of the turning, the distance from the center of the turning to the tip of the cutting tool is gradually increased, and the tip is moved along a spiral trajectory, and at the stage when the distance reaches the maximum, the maximum state is maintained to form an inner wall in an annular shape,

(2) in the outer region of the workpiece 3 away from the center of the revolution, the distance from the center of the revolution to the tip of the cutting tool 2 is gradually reduced, whereby the tip is moved along a spiral trajectory, and at the stage when the distance is minimized, the minimum state is maintained to form an outer wall in a circular shape,

thereby forming a circular ring shape.

In the above embodiment, the annular shape can be obtained quickly.

As described above, in the present invention, the inner peripheral surface and the outer peripheral surface of various shapes can be formed quickly by cutting the workpiece 3 with a load of a cutting speed, and a separate control is not necessary at the time of applying the load, thereby realizing a simple control.

Examples

An embodiment is characterized in that: a plurality of spindles 1 and a cutting tool 2 protruding from the spindles 1 are used.

In such an embodiment, the cutting speed can be further improved by cutting with the plurality of cutting tools 2, and on the other hand, the properties of the cutting surfaces of the individual cutting tools 2 can be averaged to ensure a more uniform cutting surface.

Industrial applicability

Thus, the present invention can ensure various shapes while achieving a uniform cutting surface on the inner peripheral surface and the outer peripheral surface of the workpiece at a constant cutting speed, and is of great utility value.

Claims (8)

1. A cutting method for an inner peripheral surface or an outer peripheral surface of a workpiece,

the method for cutting an inner peripheral surface or an outer peripheral surface of a workpiece by a cutting tool protruding from a spindle that revolves around a predetermined position and has a radius of the revolution adjustable, wherein when a revolution angular velocity of the spindle is represented by ω, a distance from the center of the revolution to a tip end of the cutting tool is represented by R, and a constant value C is set as a cutting velocity at the tip end of the cutting tool, ω is controlled to vary in accordance with a change in the distance R so that the following formula 1 is satisfied,

formula 1:

thereby, the cutting speed of the cutting tool is set to be constant, whereinRepresenting the time differential of said distance R.

2. The cutting method for an inner peripheral surface or an outer peripheral surface of a workpiece according to claim 1,

when a workpiece is placed on a table, the center position of the revolution of the spindle is set to be movable in a direction orthogonal or an oblique direction with respect to a plane orthogonal to the center axis of the revolution, and when the center position of the revolution of the spindle is movable in the oblique direction, the table is moved in the direction of the plane in accordance with the movement, whereby the support position of the workpiece on the table is set to be the distance R from the center position of the revolution of the spindle, and a state in which cutting is possible is maintained.

3. The cutting method for an inner peripheral surface or an outer peripheral surface of a workpiece according to claim 1,

when a workpiece is placed on a table of a machining center for performing not only cutting but also other machining on the workpiece via a rotatable table, the center position of the revolution of the spindle is made movable in a direction orthogonal or oblique to a plane orthogonal to the center axis of the revolution, and when the table is movable in the oblique direction, the table is moved in the direction of the plane in accordance with the movement, whereby the support position of the table on the table for the workpiece is set so that the cutting position of the workpiece is at the distance R from the center position of the revolution of the spindle, and the state in which cutting is possible is maintained.

4. The cutting method for an inner peripheral surface or an outer peripheral surface of a workpiece according to claim 1,

when a workpiece is gripped by an arm of a robot, the center position of the revolution of the spindle is set to be movable in a direction orthogonal or an oblique direction with respect to a plane orthogonal to the center axis of the revolution, and when the center position of the revolution of the spindle is movable in the oblique direction, the arm is moved in the direction of the plane in accordance with the movement, whereby the position gripped by the arm is set to the position where the cutting position of the workpiece is at the distance R from the center position of the revolution of the spindle, and a state where cutting is possible is maintained.

5. The method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to any one of claims 2 to 4,

the center position of the gyration of the main shaft is moved in the orthogonal direction or the oblique direction, and the distance R is gradually changed.

6. The method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to any one of claims 2 to 4,

the center position of the gyration of the main axis is moved in the orthogonal direction or the oblique direction, and the distance R is changed stepwise.

7. The cutting method for an inner peripheral surface or an outer peripheral surface of a workpiece according to claim 1,

so that the center position of the backspin of the spindle does not move in the orthogonal direction or the oblique direction,

(1) in the inner region of the workpiece near the center of revolution, the distance from the center of revolution to the tip of the cutting tool is gradually increased, so that the tip is moved along a spiral trajectory, and at the stage when the distance reaches the maximum, the maximum state is maintained to form an inner wall in an annular shape,

(2) in the outer region of the workpiece away from the center of the revolution, the distance from the center of the revolution to the tip of the cutting tool is gradually reduced, so that the tip is moved along a spiral trajectory, and at the stage when the distance is minimized, the minimum state is maintained to form an annular outer wall,

thereby, a circular ring shape is formed.

8. The method of cutting an inner peripheral surface or an outer peripheral surface of a workpiece according to any one of claims 1 to 7,

a plurality of spindles and a cutting tool protruding from the spindles are used.