JPH0255186B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for generating and machining a spheroidal surface, and its purpose is to avoid leaving cutting residue on the workpiece generation surface, etc. at the center of rotation of the workpiece while the cutting edge of the tool is in circular motion. The purpose of this process is to create a high-precision spheroidal surface.

Conventionally, in order to create a spheroidal surface and other aspherical surfaces, a spindle device 1 for attaching a workpiece W to the end face of a spindle 2 and rotating it at high speed is provided so as to be movable in the axis direction of the spindle, as shown in FIG. At the same time, the cutting tool 3 is fixed on a slide table 4 that can be moved in a direction perpendicular to the spindle axis, and while the workpiece W is rotating at high speed, the slide table 4 and the spindle device 1 are fed by numerical control to adjust the cutting edge. There is a method that creates a spheroidal surface by drawing a predetermined ellipse or the like.

In such conventional devices, since the rotational speed of the workpiece at the cutting point of the cutting tool is the cutting speed, cutting cannot be performed at the center of rotation of the workpiece because the cutting speed approaches zero, resulting in uncut residue.

In order to eliminate such conventional drawbacks, the present invention has the following features:
The purpose is to create a spheroidal surface by rotating the tool side, to avoid leaving uncut parts at the center of rotation of the workpiece, and to create a spheroidal surface of all specifications for a constant tool rotation radius. The purpose of this invention is to provide a highly versatile processing device that is equipped with adjustment elements that can perform the following steps.

The principle of creating an ellipsoid of revolution according to the present invention will be explained.

Generally, when an ellipsoid of revolution is expressed in an xyz coordinate system, x ² /a ² +y ² +z ² /b ² =1 (a: major axis, b: minor axis) The axis of rotational symmetry is the x-axis. This curved surface is an envelope surface of an inscribed sphere centered on a point on the x-axis. Therefore, as shown in Figure 2, the tool side passes through Oc and is tilted by θ with the x-axis as the rotation axis, rotates with the rotating tool radius, and if the workpiece side rotates once around the x-axis, the inscribed sphere Oc A part QQ′⌒−SS′⌒ is created. When part of this spherical surface includes MM', MM' of the ellipsoid is cut. Move the position of Oc along the x-axis to the center position of the sphere touching the vertex T (see Figure 3) and at the same time
By changing the length of OcP, an ellipsoid of revolution MTM′ is created.

Considering the xy plane, as shown in Figure 3, the equation of the circle tangent to the vertex T on the long axis of the ellipsoid is expressed as ≡X ₀ (X-a+X ₀ ) ² +y ² = R ² ₀ .

To touch the ellipse x ² /a ² +y ² /b ² =1, X ₀ = R ₀ = b ² /a ∴sinθ=PQ/OcQ=d/2/b ² /a=ad/2b ² ...... (1) (d: Tool rotation radius) Generally, the radius of the inscribed circle is R ² =b ² {1-(a-X) ² /a ² -b ² }.

If Z and X are controlled using the relationship expressed by equation (2), an ellipsoid of revolution can be created.

An example of a processing device to which such a creation principle is applied is shown in FIGS. 4 and 5.

10 is a bed, and on this bed 10 a tool support stand 11 and a workpiece support stand 12 are provided.
The tool support stand 11 includes a face plate 21 that supports the tool 20.
A tool headstock 23 that rotatably supports a rotating spindle 22 equipped with a rotary spindle 22, a slide base 24 and a guide base 25 for sliding the headstock 23 in a direction parallel to the spindle axis U, and a guide base 25. It is comprised of a swivel base 26 and a swivel support base 27 on which a rotary machine is placed and can be rotated about an axis V perpendicular to the spindle axis U. A spindle drive motor 28 is mounted on the spindle stock 23, and pulleys 23a, 28a and a belt 29
It is rotatably connected to the rotating main shaft 22 via. On the face plate 21 is a tool 20 made of a diamond cutting tool that is eccentric to the center of rotation and protrudes in the axial direction.
is provided, and the cutting edge 20a of the tool performs a circular motion with a rotational diameter d. Note that the tool 20 is not limited to a single-point cutting tool, and a milling cutter or a grindstone can also be used. The swivel support base 27 is provided with an adjustment handle 27a, and this handle 27a is connected to the swivel base 29 via a worm and a worm gear (not shown). The turning angle θ can be adjusted. Guide base 25 placed on swivel table 26
, a servo motor is connected to a slide table 24 on which a headstock 23 is mounted and a feed screw (not shown).
SMa is provided to control the amount of movement Z in FIG.

The workpiece support device 12 includes a workhead 3 rotatably supporting a rotating main shaft 30 that supports a workpiece W.
1, a movable base 32 and a slide base 33 for sliding the work head 31 in a direction parallel to the spindle axis T, and a guide base 34 for slidingly guiding the slide base 33 in a direction perpendicular to the spindle axis T.
It is composed of. The work head 31
A main shaft drive motor 35 is provided and connected to one end of the rotating main shaft 30 via a speed reduction mechanism. A face plate 30a is provided at the other end of the rotating main shaft 30, and a workpiece W is concentrically fixed to this face plate 30a. The guide base 34 includes an adjustment handle 3.
4a, and a feed screw (not shown) that screws into the slide base 33 is connected to the handle 34a. By turning this handle 34a, the work head 31 is moved in a direction perpendicular to the axis, and the work head 31 is set in a positional relationship such that the cutting point of the tool 20 passes on the work rotation center line T, as shown in FIG. be able to. The slide base 33 is provided with a servo motor SMa connected to a feed screw (not shown) that is screwed into the slide base 32 and controls movement of the work head 31 in the work axis direction.

40 is a numerical control device, which controls the servo motor.
SMa and SMb are controlled to maintain the relationship expressed by equation (2) above. Here, as shown in FIG. 5, the angle θ formed by the tool rotation axis U and the workpiece rotation axis T is constant, and the Z dimension with respect to the intersection Oc of both axes is controlled by the servo motor SMa. That is, the intersection point Oc is an immovable point if the angle θ is constant, and if the headstock 23 is fed forward along the tool rotation axis U, Z will increase, and if it is fed backward, Z will decrease. Also, the X dimension with respect to the intersection Oc is the servo motor
Controlled by SMb, if the work head 31 is fed forward (to the left in the figure) along the work rotation axis T, X will decrease, and if it is sent backward (to the right in the figure), X will increase. Note that the angle θ formed by both axes is adjusted when changing the major axis a and minor axis b of the ellipsoid of revolution based on the relationship in equation (1) above.
If this angle θ is changed, the tool cutting edge no longer passes on the workpiece rotation axis T, so it is necessary to make an adjustment using the handle 34a to move the workhead 31 in a direction perpendicular to the workpiece rotation axis T. These adjustments are made manually as the creation specifications (major axis a, minor axis b) of the spheroid are changed.

By calculating the above formula (1) with an electronic computer,
Although several sets of Z and X are found, the number of sets to be found may be increased or decreased depending on the required accuracy. The Z I asked for
The numerical control device 40 performs two-dimensional pulse distribution by connecting a large number of points defined by
In this case, the Z and X point group data are programmed in advance and stored in the storage device 41 built into the numerical control device 40. Among the simultaneous two-axis pulse trains output from the numerical control device 40, the A-axis pulse train is applied to the servo motor SMa to move the tool headstock 23 to the tool rotation axis U and calculate the distance a from the intersection point Oc to the cutting edge rotation plane. The pulse train for the other B-axis is given to the servo motor SMb and the pulse train is sent to the work head 3.
1 in the direction of the workpiece rotation axis T, and
Controls the distance X to the work creation surface with respect to Oc. In this way, one set of Z and X is given, and the workpiece W is 1
When rotated, part of the paraboloid in Figure 2
Since MM' is machined, another set of Z and X is given every time the work W is rotated once, and by sequentially shifting the machining point in the Z-axis direction, an ellipsoid of revolution can be created.

Note that it is also possible to control the machining point along a helical locus by shifting the machining point in the z-axis direction according to the rotation of the workpiece. In this case, the work drive motor is also a servo motor, and the numerical control device 40 is programmed with a set of point group data (α, Z, X) including the work rotation angle α, and this data is Therefore, it is sufficient to perform pulse distribution for three axes simultaneously and apply the distributed pulses to each servo motor.

According to the present invention, the tool is rotated around an axis that makes an angle with the workpiece axis, the tool and the workpiece are controlled to move relative to each other in the direction of the tool rotation axis and the workpiece rotation axis, and the workpiece is rotated. Since the spheroid is created by moving the tool to draw an ellipsoid on the workpiece creation surface, even if the cutting point of the tool is at the center of rotation of the workpiece, the cutting speed will not decrease and no uncut material will be left. .

Furthermore, since the A-axis and B-axis, which are the control axes, do not have to be controlled as a function of the rotation angle of the tool rotating at high speed, control is relatively easy and the mechanical system can be easily designed.

In addition, the major axis a and minor axis b, which are the creation parameters of the spheroidal surface, can be changed arbitrarily by adjusting the angle θ formed by the tool rotation axis with respect to the workpiece rotation axis, so it is a versatile processing device. It has the advantage of being able to

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional device, Fig. 2 is an explanatory diagram of the principle of creation of the spheroidal surface according to the present invention, Fig. 3 is a diagram showing the relationship with the inscribed sphere touching the vertex, Fig. 4,
FIG. 5 shows a processing apparatus according to an embodiment of the present invention, with FIG. 4 being a front view and FIG. 5 being a plan view. DESCRIPTION OF SYMBOLS 11... Tool support device, 12... Work support device, 20... Tool, 23... Tool headstock, 24...
...Sliding base, 25...Guide base, 26...Swivel base, 27...Swivel support base, 30...Rotating main shaft, 3
1...Work head, 32...Sliding table, 33...
Slide base, 34... Guide base, SMa,
SMb...Servo motor.

Claims (1)

[Scope of Claims] 1. A workpiece support device that supports and rotates a workpiece on which an ellipsoidal surface of revolution is formed, and has a rotational axis inclined with respect to the rotational axis of the workpiece, and has a tool eccentrically protruding from one end thereof. a rotating spindle; a tool headstock rotatably supporting the rotating spindle; a first feeding means for moving the rotating spindle and the workpiece relative to each other in the axial direction of the rotating spindle; The tool has a second feeding means for relatively moving the tool, and a numerical control device, and rotates the tool to cause the first feeding means to move the rotating main shaft in the axial direction and the second feeding means to move the workpiece in the axial direction. In a processing device that controls and cuts a spheroidal surface, the major axis of the spheroidal surface is a, the minor axis is b, and the rotating diameter of the tool is d, and the angle θ between the axis of the rotational spindle and the axis of the workpiece is sinθ. = ad/2b ^2The amount of axial movement of the rotating main shaft by the first feeding means Z and the amount of axial movement of the workpiece by the second feeding means A spheroidal ellipsoidal surface generation processing device is characterized in that spheroidal ellipsoidal surface generation processing is performed by controlling to maintain the following relationship. 2. The first feeding means includes a guide means for slidably guiding a tool headstock that rotatably supports the rotary spindle in an axial direction of the rotary spindle, and a guide means for moving the tool headstock guided by the guide means. The spheroidal surface generating processing device according to claim 1, comprising a feed screw mechanism and a servo motor connected to the feed screw mechanism. 3. The second feeding means includes a guiding means for slidably guiding the work supporting device in the direction of the rotational axis of the work, a feed screw mechanism for moving the work supporting device guided by the guiding means, and a feeding screw mechanism for moving the work supporting device guided by the guiding means. The spheroidal surface generating processing device according to claim 1, comprising a servo motor connected to a screw mechanism. 4. The first feeding means rotates the guide means for guiding the tool headstock about an axis that is perpendicular to a plane including the axis of the rotational spindle and the rotational axis of the workpiece and orthogonal to the axis of the rotational spindle. 3. The spheroidal surface generating processing apparatus according to claim 2, further comprising a turning adjustment means for adjusting the spheroidal surface. 5. The spheroidal surface generating process according to claim 3, wherein the second feeding means includes movement adjusting means for adjusting the movement of the guiding means for guiding the work supporting device in a direction perpendicular to the guiding direction. Device.