JPH06126607A - Curved surface polishing device - Google Patents

Abstract

PURPOSE:To machine a curved-surface work piece' with good accuracy and remarkably improve the working efficiency by connecting an oscillating device for oscillating a polishing head to make the axis of a tool parallel to the tangential line in a working point of a work piece to the polishing head. CONSTITUTION:A curved surface polishing device includes a polishing head 14 for rotatably supporting a disc-like tool 13 round the shaft center and pressing the outer peripheral surface of the tool 13 to a surface 11a to be worked of a workpiece 11 with designated pressing force and a driving device 15 for rotating the tool 13. A NC table 16 as an oscillating device for oscillating the polishing head 14 to make the axis of the tool 13 parallel to the tangential line C in a working point 11b of a work piece 11 is connected to the polishing head 1. Thus, the outer peripheral surface of the tool 13 is pressed to a surface 11a to be worked to uniformalize the relative speed in a contact area between the tool 13 and the surface 11a to be worked. Accordingly, the working amount is equalized extending over the whole area of the contact surface of the tool 13 so that the shaps of single working traces are uniformalized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curved surface polishing apparatus for highly accurately processing a curved surface-shaped workpiece such as a reflection mirror for X-rays or an engineering lens.

[0002]

2. Description of the Related Art As a conventional curved surface polishing apparatus of this type,
For example, there is an aspherical surface processing machine disclosed in Japanese Patent Publication No. 4-50152. The aspherical surface processing machine shown in this publication is shown in FIG.
Shown in.

FIG. 5 is an enlarged sectional view showing a tool portion of a conventional aspherical surface processing machine. In the figure, reference numeral 1 denotes a work piece, and a work surface 1 formed of a concave curved surface on the upper surface of the work piece 1.
a is formed. The workpiece 1 is placed and fixed on a rotary table (not shown), and is rotated about the central axis a during machining.

Reference numeral 2 denotes a tool formed in a substantially round bar shape. The tool 2 is supported by a spindle 3 so as to be rotatable around an axial center thereof, and is connected to a drive device (not shown) to rotate. It has become. In the figure, the alternate long and short dash line b indicates the axis of rotation of the tool 2. The spindle 3 is supported by a support member 4 via a compression coil spring 5, and is mounted on the support member 4 so as to be vertically movable. Then, the support member 4 rotates so as to move the tool 2 along the machining surface 1a,
It was structured to be driven by a lifting device.

In the conventional device thus constructed, the lower end surface of the tool 2 is pressed against the machining point of the machining surface 1a (this machining point is indicated by reference numeral 6 in the drawing) to rotate, and at the same time, the workpiece is machined. Processing was performed by rotating 1 around the center line a. The inclination angle when the tool 2 is pressed against the machining point 6 is the angle at which the rotation axis b of the tool 2 coincides with the normal direction at the machining point 6.

Further, the pressing force when the tool 2 is pressed against the tool 2 and the spindle 3 is set to be a force that is obtained by subtracting the elastic force of the compression coil spring 5 from the force of the tool 2 and the spindle 3 being lowered. That is, in this apparatus, the working pressure is increased by lowering the support member 4, and is increased by increasing the working pressure.

[0007]

However, in the conventional aspherical surface processing machine configured as described above, since the rotation axis b of the tool 2 is made to coincide with the normal direction at the processing point 6, the processing is performed. The center of rotation of the lower end surface of the tool 2 hits the processing surface 1a. That is, since the outer peripheral portion of the tool 2 has a relatively higher rotational speed than the radial central portion, the outer peripheral portion of the tool 2 has a larger amount of machining than the radial central portion. Therefore, the shape of the single processing mark was non-uniform. Further, when the polishing head composed of the tool 2 and the spindle 3 is tilted, the pressing force (processing pressure) in the axial direction is smaller than that in the vertical state, so that the processing pressure can be kept constant over the entire processing surface 1a. Can not. In other words, the processing pressure decreases as the angle θ shown in FIG. 5 increases.

That is, in the conventional device, the above-mentioned tool 2 is used.
There is a problem that the shape accuracy of the machined surface 1a becomes low due to two problems, namely, the contact structure and the problem that the processing pressure becomes non-uniform.

In order to make the working pressure uniform over the entire working surface 1a, the support member 4 may be moved up and down according to the tilt angle. To do so, a sensor or a support for detecting the tilt angle is used. A drive device for raising and lowering the members must be provided, which complicates the structure.

Furthermore, when processing an aspherical surface with a conventional aspherical machine, the tool 2 having a small outer diameter must be used in order to make the processing pressure distribution uniform. That is, in such a case, the relative speed between the tool 2 and the machined surface becomes small and the machining efficiency becomes extremely low.

The present invention has been made in order to solve the above-mentioned problems, and highly accurately processes a curved workpiece such as a reflection mirror for X-rays or an engineering lens, and
The purpose is to significantly improve processing efficiency.

[0012]

A curved surface polishing apparatus according to a first aspect of the present invention supports a disk-shaped tool rotatably around an axis, and applies an outer peripheral surface of the tool to a machined surface of a workpiece in a predetermined manner. A polishing head that presses with pressure and a drive device that rotates the tool are provided, and the polishing head is oscillated so that the axis of the tool is parallel to the tangent line at the processing point of the workpiece. The device is connected.

A curved surface polishing apparatus according to a second aspect of the present invention is the curved surface polishing apparatus according to the first aspect of the present invention, in which the polishing head supports a tool supporting shaft member and the shaft member so as to be movable along the pressing direction. And a polishing head body for applying a pressing force to the polishing head body, and a balancer having a weight equivalent to the weight of the shaft member with the tool mounted thereon is movable in parallel with the moving direction of the shaft member. The balancer is provided to pull the shaft member from above.

[0014]

According to the curved surface polishing apparatus of the first aspect of the present invention, since the outer peripheral surface of the disk-shaped tool is pressed against the machining surface, the relative speed at the contact portion between the tool and the machining surface becomes uniform.

According to the curved surface polishing apparatus of the second invention,
Since the shaft member is pulled from above by the balancer having substantially the same weight, the shaft member becomes substantially weightless. For this reason,
Even if the polishing head is tilted, the processing pressure applied to the processing point does not change.

[0016]

【Example】

Example. 1 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. In this embodiment, an apparatus adopting both the first invention and the second invention is shown.

FIG. 1 is a front view of a curved surface polishing apparatus according to the present invention, and FIG. 2 is a side view of the same. In these figures,
Reference numeral 11 denotes a workpiece, and this workpiece 11 is an X-ray reflection mirror, and is mounted and fixed on a support (not shown) with a processing surface 11a having a concave curved surface facing upward.

Reference numeral 12 denotes a curved surface polishing apparatus according to the present invention. The curved surface polishing apparatus 12 has a polishing head 14 for pressing a tool 13 against the workpiece 11, a drive unit 15 for rotating the tool 13, and these polishing heads 14. And an NC table 16 as an oscillating device according to the first invention for moving the drive device 15.

The tool 13 is formed in a disk shape, and a tool rotating shaft 17 is fixed to the shaft center portion thereof. The axis of the tool rotating shaft 17 is determined so that the disk surface 13a of the tool 13 is oriented in a substantially horizontal direction, and is rotatably supported by the polishing head 14 via bearings 18 and 19. Further, a bevel gear 17a rotated by a drive device 15 described later is fixed to one end of the tool rotation shaft 17.

The polishing head 14 has the tool rotating shaft 17
And a polishing head main body 23 for movably supporting the shaft member 20 through slide bearings 21 and 22 in a substantially vertical direction orthogonal to the axial direction of the tool rotation shaft 17. And is supported by an NC table 16 described later. A lower end portion of the shaft member 20 is formed in a fork shape, and the tool 13 is faced to the fork-shaped portion, and the tool rotating shaft 17 is supported on the lower end of the fork. The upper part of the shaft member 20 has a pressing mechanism 2 which will be described later.
4 and the balancer 25. In addition, a stopper 20a provided at a substantially central portion of the shaft member 20 in the up-down direction is a stopper for retaining. In the illustrated state, the stopper 20a is in contact with the receiving portion 23a of the polishing head main body 23, but when performing polishing, the stopper 20a is positioned above the illustrated state and is separated from the receiving portion 23a.

The polishing head main body 23 is provided with a pressing mechanism 24 for applying a pressing force to the tool 13, and a balancer 25 is mounted on the side of the shaft member supporting portion. The pressure mechanism 24 includes a pressure setting screw 24a screwed into the polishing head main body 23, a pressure sensor 24b contacting the lower end of the pressure setting screw 24a, and the pressure sensor 2
4b and the compression coil spring 24c interposed between the upper end spring bearing 20b of the shaft member 20. To use the pressurizing mechanism 24 to set the pressing force to a desired value,
This is performed by tightening or loosening the pressure setting screw 24a so that the value detected by the pressure sensor becomes a predetermined value.

The balancer 25 is formed in a cylindrical shape in this embodiment, and has a weight equivalent to the weight of the shaft member 20 to which the tool 13 is attached. The balancer 25 is movably mounted on the polishing head main body 23 via a slide bearing 26 so that the longitudinal axis of the balancer 25 is parallel to the moving axis of the shaft member 20. It is connected to the upper part of the shaft member 20 via 27. The wire 27 is used for the polishing head body 2
The structure is such that the weight of the balancer 25 is applied to the shaft member 20 in a substantially upward direction by being guided to the upper end portion of the shaft member 20 by being guided by the wire supporting members 28 and 29 pivotally supported on the upper part of the shaft 3. That is, the balancer 25 has a structure in which the shaft member 20 is pulled substantially upward.

The driving device 15 is provided with the polishing head 14.
A tool rotation driving motor 31 supported by an NC table 16, which will be described later, a shaft 32 connected to an output shaft 31a of the motor 31 and extending downward, and a gear assembly 33 connected to a lower end of the shaft 32. It consists of and.

The shaft 32 has a structure with high flexibility, and can be easily bent or expanded in the axial direction. The gear assembly 33 includes the shaft member 20.
Has a rotating shaft 37 rotatably supported by bearing blocks 35 and 36 on a support block 34 of the umbrella, and the lower end of the shaft 32 is coupled to the upper end of the rotating shaft 37, and an umbrella that meshes with the bevel gear 17a. The structure is such that the gear 38 is fixed to the lower end.

The NC table 16 includes the polishing head 14
The driving device 15 is scanned to relatively move the contact point between the tool 13 and the workpiece 11 on the machining surface 11a so that the machining surface 11a is entirely polished. The scanning locus of the NC table 16 is obtained by measuring the pre-machined shape of the workpiece 11 in advance and determining the coordinates (X-axis and Y-axis in the drawing) on the machined surface 11a from the difference between the pre-machined shape and the target shape. , Z
The required amount of polishing in the axis and the rotation A axis) is obtained, and the required amount of polishing is set as a locus for polishing by the tool 13. That is, scanning is performed at a scanning speed such that the tool 13 stays for the time required to polish the required polishing amount.

Next, the operation of the curved surface polishing apparatus 12 according to the present invention configured as described above will be described. First,
The NC head 16 lowers the polishing head 14 and the drive unit 15 to bring the outer peripheral surface 13b of the tool 13 at the lower end into contact with the machined surface 11a of the workpiece 11. At this time,
The polishing head 14 and the drive unit 15 are arranged such that the axis of the tool rotating shaft 17 is parallel to the tangent line (indicated by the chain double-dashed line C in FIG. 1) at the processing point (indicated by reference numeral 11b in FIG. 1) on the processing surface 11a. Rock. Further, at this time, the processing pressure applied from the tool 13 to the workpiece 11 is zero because the weight of the balancer 25 acts on the shaft member 23 of the polishing head 14.

Next, the pressure setting screw 24a of the pressurizing mechanism 24
And a predetermined processing pressure is applied by the compression coil spring 24c. This processing pressure is applied from the normal direction at the processing point 11b. When applying the processing pressure, the shaft member 20 moves up and down with respect to the polishing head main body 23. At this time, the shaft 3 of the drive unit 15 is moved.
2 flexes as it extends.

Then, the motor 31 is operated in this state. The rotation of the output shaft 31a of the motor 31 is transmitted from the shaft 32 to the gear assembly 33, and is transmitted from the bevel gear 28 of the gear assembly 33 to the bevel gear 17a so that the rotation direction is changed and the tool is rotated via the tool rotation shaft 17. It is transmitted to 13. As a result, the tool 13 is driven to rotate about its axis.

In this manner, while the tool 13 is rotated, the polishing is performed while supplying the abrasive, which is the working liquid, to the contact surface between the tool 13 and the workpiece 11. This polishing is performed by scanning the NC head 16 with the polishing head 14 and the driving device 15 as described above. That is, the polishing head 14 and the driving device 15 are swung in the rotational A-axis direction in the drawing so that the axis line of the tool rotation shaft 17 is parallel to the tangent line at the processing point of the processing surface 11a, and at the same time the X-axis, Scanning is performed in the Y-axis and Z-axis directions.

Therefore, in the curved surface polishing apparatus 12 thus constructed, the outer peripheral surface 13b of the disk-shaped tool 13 is pressed against the processing surface 11a, so that the tool 13
And the relative speed at the contact portion between the processed surface 11a becomes uniform.

Further, since the shaft member 20 of the polishing head 14 is pulled from above by the balancer 25 having substantially the same weight, the shaft member 20 becomes substantially weightless. Therefore, even if the polishing head 14 is tilted, the processing pressure applied to the processing point does not change.

In this embodiment, when the tool 13 is rotated, the shaft 31 that rotates together with the motor output shaft 31a is connected to the pair of bevel gears 38 and 17a to change the power transmission direction. The member to be changed should be determined by the rotation speed and the like, and is not limited to the bevel gears 38 and 17a as shown in this embodiment.

Example 2. Further, the drive device 15 is not limited to the shaft drive type as shown in this embodiment, and the output shaft of the motor and the tool rotation shaft may be parallel to each other as shown in FIGS. 3 and 4, for example. it can.

FIG. 3 is a front view showing another embodiment of the curved surface polishing apparatus, and FIG. 4 is a side view of the same, in which only the polishing head and the driving apparatus are shown. Further, in these figures, the same or equivalent members as those described in FIG. 1 and FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted. The curved surface polishing apparatus shown in FIGS. 3 and 4 has the same structure as that of the curved surface polishing apparatus 12 of the above-mentioned embodiment except that the structure of the driving device is different.

Reference numeral 51 denotes a belt drive type drive device. The belt drive type drive device 51 has a motor 52 whose axial direction is parallel to the tool rotating shaft 17 and a drive pulley fixed to an output shaft 52a of the motor 52. 53, a driven pulley 54 fixed to the tool rotating shaft 17, a belt 55 wound around these pulleys 53, 54, and a tension pulley 5 for adjusting the tension of the belt 55.
It is composed of 6 mag.

When the belt drive type drive device 51 thus constructed is used, the axial distance between the drive pulley 53 and the driven pulley 54 changes when the shaft member 20 moves up and down with respect to the polishing head body 23. Become.

The power transmission member for parallelizing the output shaft 52a of the motor 52 and the tool rotation shaft 17 is not limited to the belt 55 as shown in FIGS. Other than belts can be used depending on the requirements.

Further, in each of the above-mentioned embodiments, the polishing head 14 and the driving devices 15 and 51 are driven by four axes (X axis, Y axis).
Axis, Z axis, and rotation A axis), the selection of the type of axis and the number of axes should be determined by the shape of the workpiece, the required accuracy, etc., and is not limited to this embodiment. .

[0039]

As described above, the curved surface polishing apparatus according to the first aspect of the present invention supports a disk-shaped tool rotatably around its axis and sets the outer peripheral surface of the tool as a predetermined machining surface of a workpiece. A polishing head that presses with a pressing force and a drive device that rotates the tool are provided, and the swinging head causes the polishing head to swing so that the axis of the tool is parallel to the tangent line at the processing point of the workpiece. Since the moving device is connected, the outer peripheral surface of the disk-shaped tool is pressed against the machining surface, so that the relative speed at the contact portion between the tool and the machining surface becomes uniform. For this reason, since the machining amount becomes equal over the entire contact surface of the tool, the shape of the single machining mark becomes uniform.

A curved surface polishing apparatus according to a second aspect of the present invention is the curved surface polishing apparatus of the first aspect, wherein the polishing head supports a tool supporting shaft member and the shaft member so as to be movable along a pressing direction. And a polishing head body for applying a pressing force to the polishing head body, and a balancer having a weight equivalent to the weight of the shaft member with the tool mounted thereon is movable in parallel with the moving direction of the shaft member. Since the balancer is provided and the shaft member is pulled from above by the balancer, the shaft member is pulled from above by the balancer having substantially the same weight, so that the shaft member becomes substantially weightless. For this reason, since the processing pressure applied to the processing point does not change even if the polishing head is tilted, an error due to the polishing position of the processing pressure does not occur, and polishing can be performed with uniform processing pressure over the entire processing surface. .

Therefore, the curved surface polishing apparatus according to the present invention has the effect of improving the shape accuracy of the machined surface.

Further, when polishing an aspherical machined surface, it is not necessary to use a tool having a small outer diameter in order to make the machining pressure distribution uniform, and the tool outer diameter can be set to a large value. Since the relative speed with the machined surface also increases,
The polishing can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a front view of a curved surface polishing apparatus according to the present invention.

FIG. 2 is a side view of the curved surface polishing apparatus according to the present invention.

FIG. 3 is a front view showing another embodiment of the curved surface polishing apparatus.

FIG. 4 is a side view showing another embodiment of the curved surface polishing apparatus.

FIG. 5 is an enlarged sectional view showing a tool portion of a conventional aspherical surface processing machine.

[Explanation of symbols]

 13 Tool 14 Polishing Head 15 Drive Device 16 NC Table 20 Shaft Member 23 Polishing Head Main Body 24 Pressurizing Mechanism 25 Balancer 27 Wire

Claims (2)

[Claims] 1. A polishing head, which rotatably supports a disk-shaped tool around an axis and presses the outer peripheral surface of the tool against a machining surface formed of a curved surface of a workpiece with a predetermined pressing force. A drive device for rotating the tool, and a swinging device connected to the polishing head for swinging the polishing head to make the axis of the tool parallel to the tangent line at the processing point of the workpiece. Curved surface polishing equipment. 2. The curved surface polishing apparatus according to claim 1,
The polishing head is formed by a shaft member that supports the tool, and a polishing head body that movably supports the shaft member along the pressing direction and applies a pressing force, and the tool is mounted on the polishing head body. A curved surface polishing apparatus characterized in that a balancer having a weight equivalent to the weight of the shaft member in the opened state is movably provided along an axis parallel to the moving axis of the shaft member, and the shaft member is pulled from above by the balancer.