JP4225192B2 - Truing device and truing method - Google Patents

Description

The present invention relates to Ruth Ruingu method to correct the grinding wheel to rotate.

  In recent years, NC machine tools capable of ultra-precision machining of molds for optical components such as lenses have been developed. In this type of NC machine tool for ultra-precision machining, it is possible to grind the uneven surface of a mold as a work with high accuracy using a small-diameter grindstone. If the workpiece diameter is approximately 10 mm or less, the grinding wheel shaft should be tilted so that a thick grinding wheel shaft with the highest possible rigidity can be used while avoiding interference between the outer edge of the concave surface of the workpiece and the grinding wheel shaft attached to the grinding wheel. There is an oblique axis NC machine tool. This oblique axis NC machine tool uses a small-diameter cylindrical grindstone to grind the concave surface of the workpiece by the edge portion of the grindstone tip (see Patent Document 1, FIG. 6B).

  In this oblique axis NC machine tool, when the edge portion is trued, the posture of the grindstone shaft is changed so that the grindstone shaft is vertical from an oblique state, and a swing-type truer is provided on the work shaft for rotating the workpiece. A desired curvature was formed at the edge portion by mounting and swinging movement of the work shaft (see Patent Document 2, FIGS. 2A and 2B). When the truing is performed in a state where the grindstone shaft is in an oblique posture, an operator manually performs a stick grindstone.

JP 2003-11057 A

JP 2000-24898 A

  As a conventional problem, if the swinging-type truer shown in Patent Document 2 is attached to the work shaft and truing, a swiveling device that changes the slanting grindstone shaft to a vertical posture is required, which increases costs. To do. In addition, in the method of truing with a swing-type truer attached to the workpiece shaft, a constant value is required as the turning radius of the truer, and therefore a radius of curvature smaller than this value cannot be formed. That is, a sharp edge cannot be formed. In addition, since the swinging-type truer is made of a single stone, the wear of the truer is large.

  In order to form a sharp edge, it is possible to manually truing the front end surface of the grindstone and the cylindrical portion using a stick grindstone, but the shape of the edge portion varies depending on the skill of the operator. When grinding is performed on the edge portion having a variation, the quality of the processed surface, particularly the variation in shape error, increases.

The present invention has been made to solve the conventional problems relating to provide a Ruth Ruingu method can accurately correct the oblique grinding wheel.

The truing method according to claim 1, wherein a cylindrical grindstone that rotates about a grindstone rotation axis rotates a spherical grinder that rotates about a truer rotation axis that obliquely intersects the grindstone rotation axis within a plane formed by two orthogonal axes. In the truing method for synchronously controlling the truer and the grindstone in the plane so that the grindstone rotation axis and the truer rotation axis intersect and correct on the side forming an acute angle , the truer and the grindstone Are moved relative to each other in the two orthogonal directions to bring the true point of the truer into contact with the grinding point of the grindstone, and the truer 2 between the truer and the grindstone when the true point and the grinding point are in contact with each other. The relative position in the axial direction is memorized, and the front of the truer and the grindstone is adjusted so that the cutting amount of truing is based on the stored relative position in the two biaxial directions. Set the relative movement path of the orthogonal biaxial directions, the front end surface of said truing point along the relative movement path is relatively moved toward the rotation center from the outer periphery of the grinding wheel said grinding wheel at the rear conical surface of the truer Correcting, the truing point is relatively moved along the relative movement path from the front end to the rear end of the grindstone in the direction of the grindstone rotation axis to correct the cylindrical surface of the grindstone with the front conical surface of the truer. Features.

The truing method according to claim 2 is the truing point of the truer and the grinding point of the grindstone according to claim 1, based on an image of a microscope in which the truer and the tip of the grindstone are enlarged and measured in the plane. The truer and the grindstone are moved relative to each other in an axial direction perpendicular to the plane so that the truer and the grindstone are focused on the microscope image without being out of focus. The truing point and the grinding point are brought into contact with each other by relatively moving in two axial directions .

According to the truing method of the invention of claim 1, the truer when the truing point of the truer and the grinding point of the grindstone are brought into contact with each other by moving the abacus spherical truer and the grindstone relative to each other in two orthogonal axes. And the relative position in the orthogonal biaxial direction between the grindstone and the grindstone are set, and a relative movement path in the orthogonal biaxial direction between the grindstone and the truer is set so that the cutting amount of truing is based on the relative position. Since the grindstone rotating on the side that forms the acute angle of the intersecting rotation axis and the truer are synchronously moved relative to each other , the grindstone for oblique axis grinding can be accurately trued without changing the oblique grindstone axis to a vertical posture. it can. The edge portion of the grindstone tip can be formed with a desired curvature, and a sharp edge can be formed. Since the rotating grindstone is trued by rotating the abacus-shaped spherical truer, wear of the truer can be reduced. Further, since the grindstone and the truer are arranged close to each other, there is an effect that the installation space can be reduced.
According to the truing method of the invention according to claim 2, the true point of the truer based on a microscope image measured by enlarging the tip of the truer and the grindstone in a plane where the truer rotational axis is oblique to the grindstone rotational axis. And the grinding point of the grindstone are moved relative to each other in the axial direction perpendicular to the plane so that the image of the microscope is imaged without being out of focus. Then, the truer and the grindstone are relatively moved in the orthogonal biaxial direction within the plane based on the image of the microscope so that the truing point and the grinding point are in contact with each other. Accordingly, in addition to the effect of the invention according to claim 1, the true position of the truer and the grindstone when the truing point and the grinding point are in contact with each other is detected with high accuracy, and truing It is possible to accurately set the depth of cut.

  Embodiments of a truing device and a truing method according to the present invention will be described below with reference to the drawings. In FIG. 1, a bed 1 is installed on a base 2 via a vibration isolation table 3. A Y-axis slide table 4 is mounted on the front surface of the bed 1 by a guide mechanism 5 so as to be linearly movable in the vertical Y-axis direction. The Y-axis slide table 4 is linearly moved in the Y-axis direction by a linear motor (not shown), and the amount of movement is detected and fed back by a linear scale (not shown) for position control.

  An X-axis slide table 6 is mounted on the horizontal upper surface of the bed 1 so as to be linearly movable in the left and right X-axis directions by a guide mechanism 7. The X-axis slide table 6 is linearly moved in the X-axis direction by a linear motor 8, and the amount of movement is detected by a linear scale 9, which is fed back and position controlled.

  A workpiece support 10 is mounted on the X-axis slide table 6 by a guide mechanism 11 so as to be linearly movable in the front and rear Z-axis directions. The workpiece support 10 is linearly moved in the Z-axis direction by a linear motor (not shown), the amount of movement is detected by a linear scale 12, and the position is controlled by feedback.

  As described above, the Y-axis slide table 4, the X-axis slide table 6 and the workpiece support base 10 are the X-axis, Y-axis, and Z-axis straight lines configured by the guide mechanisms 5, 7, and 11 linear motors and linear scales, respectively. The moving devices 13 to 15 are relatively linearly moved in the three orthogonal axes.

  A rotary table 16 is mounted on the Y-axis slide table 4 so as to be rotatable about a B-axis parallel to the Y-axis, and is rotated by a direct drive motor (not shown) directly connected to the rotary table 16. ) Is detected and fed back to control the position.

  A known right-angled two-way fine movement device 51 is placed on the upper surface of the rotary table 16, and the adjustment table 52 on the upper surface of the right-angled two-way fine movement device 51 is movable in two orthogonal horizontal directions. The rotation original position of the rotary table 16 is adjusted so that the two right-angle directions of the right-angle two-direction fine movement device 51 are parallel to the X axis and the Y axis, respectively.

  On the upper surface of the adjustment table 52, an inclined table 53 having an inclined surface with an inclination angle of 45 degrees with respect to the horizontal upper surface of the rotary table 16 is placed. The inclined surface can be rotated by a hydrostatic air bearing (not shown). A grindstone base 62 having a grindstone shaft 61 that is supported by and driven by an air turbine (not shown) is disposed. As shown in FIG. 2, the grindstone shaft 61 is parallel to the inclined surface of the tilt table 53, that is, is inclined by 45 degrees with respect to the horizontal plane, and a cylindrical grindstone is provided at the tip portion (lower side in the vertical direction) of the grindstone shaft 61. T is detachably mounted, and the upper end of the grindstone T is a grinding point Tg for grinding the workpiece W.

  The right-angled two-way fine movement device 51 adjusts the grinding point Tg so as to coincide with the B axis that is the rotation center of the rotary table when the workpiece W is ground. As a result, the position of the grinding point Tg at the tip of the grindstone T can remain on the B-axis turning axis line (on the B-axis) with almost no deviation, regardless of the angle at which the rotary table turns.

  A truing device 71 is disposed on the right side of the workpiece shaft 37 and on the front surface of the workpiece support 10 so that the rotation axis of the truer shaft 72 is parallel to the Y axis (vertical) as shown in FIG. Yes. A truer shaft 72 is rotatably supported on a truing device 71 by a static pressure air bearing (not shown) and is driven by an air turbine (not shown). At the tip of the truer shaft 72 (lower side in the vertical direction), a truer 73 having a shape (an abacus ball shape) in which two cones having a head angle of 90 degrees and their bottoms are combined is detachably mounted. ing.

  Therefore, during truing, the truing device 71 is located in the overhead space of the grindstone T, and the truer shaft 72 and the grindstone shaft 61 intersect at an acute angle of 45 degrees as shown in FIG. Thus, since the truing device 71 is disposed in the overhead space of the grindstone T on the front surface of the workpiece support base 10, the entire machine tool can be made compact.

  A strobe 81 is fixed to the left front portion of the bed 1 so that the tip of the grindstone T and the truer 73 can be irradiated. A slide base 84 is placed on the right front portion of the bed 1 via a bracket. A slider 82 is guided to the slide base 84, and the slider 82 can reciprocate on the slide base 84 in the X-axis direction by a feed cylinder (not shown). A microscope 83 is mounted on the upper surface of the slider 82 to measure the grindstone T and the tip of the truer 73 in an enlarged manner. The microscope 83 is provided with a CCD camera (not shown) on the eyepiece side. As shown in FIG. 4, a monitor 101 capable of displaying a horizontal axis line 103 and a vertical axis line 104 is connected to the CCD camera. On the screen 102 of the monitor 101, the tip part of the grindstone T, the tip part of the truer 73, and the like. It is magnified and can be seen accurately.

  In FIG. 5, reference numeral 91 denotes a numerical control device (hereinafter referred to as CNC), which is connected to drive circuits DUX, DUY, DUZ, and DUB through an interface (not shown), and is used for driving the respective X, Y, and Z axes. The linear motor and the direct drive motor of the rotary table 16 are driven. The CNC 91 is connected to a program storage device 92 having a memory (not shown) via an interface. The program storage device 92 stores a grinding program for grinding the workpiece W and a truing program for truing the grindstone T.

  The CNC 91 is connected to an input device 93 including an automatic / manual changeover switch, each axis operation button, a control axis changeover switch, a truing cycle button, a grinding cycle button, a manual pulse generator 95, and the monitor. . Further, a known pulse distribution circuit (not shown) is connected to the CNC 91, and the X axis, Y axis, Z axis, and B axis can be driven synchronously by this pulse distribution circuit.

  The conditions for truing are, for example, a grinding wheel having a diameter of 5 mm as a grinding stone T, a rotational speed of 30,000 rpm, a diamond roll having diamond as a truer 73 bonded by metal bond, a rotational speed of 70,000 rpm, and a true feed speed of 5 mm. / Min, the depth of cut is 2 μm.

  The operation of the embodiment of the present invention configured as described above will be described below.

  An automatic / manual switch (not shown) of the input means 93 is switched to manual. By operating the X-axis operation button, the X-axis slide table 6 is moved by an amount set in advance in the machine so that the truer 73 is substantially in the same position in the X-axis direction as the B-axis of the rotary table 16. The Y-axis slide table 4 in which the grindstone table 62 is disposed via the rotary table 16 and the Z-axis slide table 5 in which the truing device 71 is disposed have a gap in the YZ direction so that the grindstone T and the truer do not interfere with each other. The Y-axis slide table 4 is positioned downward and the Z-axis slide table 5 is positioned rearward so as to open.

  The strobe 81 is caused to emit light and the microscope feed cylinder is operated to bring the slider 82 closer to the rotary table 16 so that an image of the grinding point Tg at the tip of the grindstone T is displayed on the monitor screen 102. The rotating grindstone T and the rotating truer 73 can be visually recognized as being stationary on the monitor screen 102. Next, the manual changeover switch (not shown) of the input device 93 is changed to the manual feed mode, and the control axis changeover switch 94 is changed to the X axis as shown in FIG. The handle 96 of the manual pulse generator 95 is rotated to generate a pulse, drive the linear motor, and move the X-axis slide table 6 to the position where the true point 73t of the truer 73 projected on the monitor screen forms an image in the field of view without being out of focus. Slightly move. As a result, the truing point 73t exactly coincides with the B-axis and the X-axis direction. That is, the truing point 73t coincides with the grinding point Tg in the X-axis direction. Next, a horizontal line position adjustment digital switch (not shown) of the monitor 101 is adjusted so that the horizontal line 103 of the monitor screen coincides with the truing point 73t.

The control axis changeover switch is changed over to the Y axis, and the grinding point Tg worn by the manual pulse generator 95 is slightly moved up to a position where the horizontal line 103 and the Y axis direction coincide with the monitor screen. The position Y1 of the Y-axis slide table 4 is stored. The control axis changeover switch is switched to the Z axis, and the Z-axis slide table 5 is finely advanced by the manual pulse generator 95 until the truing point 73t slightly contacts the grinding point Tg. The position of the Z-axis slide table 5 at this time Z1 is stored (the state of the monitor screen in FIG. 4). Based on the contact positions Y1 and Z1, the movement path of the Y-axis slide table 4 and the Z-axis slide table 5 of the truing program is set so that the truing cut amount t is obtained.

  Next, the operation of the truing cycle of the present invention will be described. When the truing cycle button of the input device 13 is pressed by the operator, the truing program is started by the CNC device. As shown in FIG. 3A, the Y-axis table 4 and the Z-axis table 5 are driven synchronously, and the truing point 73t is moved from the outer circumferential direction of the grindstone T so that the front end surface Ta of the grindstone T has a predetermined cutting amount t. It is moved toward the center of the rotation axis. The truing of the front end face Ta by the grindstone T and the truer 73 is completed at the position where the truing point 73t reaches the vicinity of the center of the grindstone rotation axis. The front end surface Ta of the grindstone T is trued by the rear conical surface 73a of the abacus spherical truer 73.

  Next, the Y-axis table 4 and the Z-axis table 5 are driven synchronously so that the truing point 73t extends in the direction of the rotation axis from the outer peripheral front end to the rear end of the grindstone T so that the cylindrical surface Tb of the grindstone T has a predetermined cut amount t. Moved along. The cylindrical surface Tb of the grindstone T is trued by the front conical surface 73b of the abacus spherical truer 73.

  When the truing of the front end surface Ta and the cylindrical surface Tb of the grindstone T is completed, the cylindrical surface tip Tg of the grindstone T is formed with a sharp edge. As described above, the truing of the grindstone T by the truing program has been described. If the correction of the grindstone T is incomplete in one process, the truing program may be repeated in the same manner.

  In the above embodiment, a method for forming a sharp edge has been described. However, by programming the grindstone T and the truer to move relative to each other with a desired radius of curvature as shown in FIG. It is possible to form.

  Moreover, in the said embodiment, although the operator visually recognized the screen of a monitor and the method of detecting the contact of the grindstone T and the truer 73 was shown, for example, a contact detection apparatus, such as acoustic emission, was provided and preset. An automatic method of automatically detecting contact by operating a contact operation program may be used.

The perspective view which shows the whole NC machine tool which concerns on embodiment of this invention The figure explaining the grinding process which concerns on embodiment of this invention The figure explaining the truing which concerns on embodiment of this invention The figure explaining the contact operation of the grindstone T and the truer concerning embodiment of this invention Block diagram of an NC machine tool according to an embodiment of the present invention The figure explaining the other Example of the truing which concerns on embodiment of this invention.

Explanation of symbols

1 ... bed, 4 ... Y-axis slide table, 5 ... Z-axis slide table,
6 ... X-axis slide table, 10 ... workpiece support table, 16 ... rotary table 71 ... truing device, 51 ... right-angle two-way fine movement device, 29 ... grinding stone table 35 ... light source, 36 ... microscope, 37 ... main shaft, W ... Workpiece, T ... Whetstone, 73 ... Trua

Claims (2)

The grindstone rotation axis and the truer rotation of a cylindrical grindstone that rotates around the grindstone rotation axis by an abacus spherical truer that rotates around a truer rotation axis that is oblique to the grindstone rotation axis in a plane formed by two orthogonal axes. In the truing method for synchronously controlling the truer and the grindstone in the plane so as to correct on the side where the axis intersects and forms an acute angle ,
The truer and the grindstone are moved relative to each other in the two orthogonal directions to bring the truer point of the truer into contact with the grinding point of the grindstone.
Storing the relative positions of the truer and the grindstone in the orthogonal biaxial direction when the truing point and the grinding point are in contact with each other;
Based on the stored relative position in the orthogonal biaxial direction, a relative movement path in the orthogonal biaxial direction between the truer and the grindstone is set so as to be the cutting amount of truing.
The truing point is relatively moved from the outer periphery of the grindstone toward the rotational axis center along the relative movement path, and the front end surface of the grindstone is corrected by the rear conical surface of the truer.
The truing point is relatively moved along the relative movement path from the front end to the rear end of the grindstone in the direction of the grindstone rotation axis , and the cylindrical surface of the grindstone is corrected by the front conical surface of the truer. Truing method . 2. The microscope image according to claim 1, wherein a true point of the truer and a grinding point of the grindstone are not defocused based on a microscope image obtained by enlarging and measuring the tip of the truer and the grindstone in the plane. The truer and the grindstone are relatively moved in an axial direction perpendicular to the plane so as to form an image, and the truer and the grindstone are relatively moved in the orthogonal two-axis directions based on the image of the microscope, A truing method comprising contacting a truing point and the grinding point.

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