JPH10146760A - Grinding wheel truing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a tip shape of a grinding wheel in a shape accurately corresponding to a tip surface shape of a truing grinding wheel by moving the edge of a tip surface of the grinding wheel along a tip surface of the truing grinding wheel in a condition where the edge of the tip surface of the grinding wheel contacts with a tip surface of the truing grinding wheel. SOLUTION: When a point θ of application is moved to the peripheral edge from the apex, the inclining direction of a surface of a cylindrical GC grinding wheel 8 contacting with the outside edge θ of a cup grinding wheel C, gradually changes in the direction parallel to an outer peripheral surface from the direction parallel to a tip surface of the cup grinding wheel C. The outside edge θis polished so as to become the same directional surface as a surface of the cylindrical GC grinding wheel 8 contacting with this. Therefore, this outside edge θ is ground from the arrow αdirection changing in an angle range of 90 degrees as the inclining direction of the surface of the contacting cylindrical GC grinding wheel 8 changes, and an inclination in all directions in a changing range is transferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding wheel truing method for forming the tip of a cylindrical grinding wheel such as a cup grinding wheel or the like and a columnar grinding wheel into a desired shape.

[0002]

2. Description of the Related Art A curve generator is used for grinding a spherical or aspherical surface such as a cemented carbide or a glass lens, a diffraction grating, or the like. A cup grindstone (diamond grindstone, etc.) or cylindrical grindstone having a cylindrical tip shape is attached to the grindstone spindle of this curve generator, and the workpiece (mold material or cemented carbide blank) attached to the work spindle is attached. , Glass blank, etc.).

[0003] The tip shape of such a grindstone needs to be trued into various shapes depending on the purpose of use of the grindstone, required accuracy, and the like. For example, in the case of a conventionally known cup grindstone, first, the tip surface is trued so as to be a plane orthogonal to the central axis, and then the outer peripheral surface is a cylindrical surface centered on the central axis. Trued. Lastly, the outer edge of the tip and the inner edge of the tip (the inner edge and the outer edge are hereinafter collectively referred to as “edges”), which are action points (portions to be ground in contact with the workpiece), improve grinding efficiency and processing accuracy. Therefore, in the longitudinal section including the central axis, the truing is performed so as to have an arc shape with high roundness.

The shape of the tip of the grinding wheel formed by truing as described above is determined by the NC (numeric) of the curve generator.
In order to realize high-precision grinding by merical control), it must be accurate at the micron level.

[0005]

However, with the truing method proposed so far, it has been almost impossible to obtain a grinding wheel shape as designed with a precision of a micron level.

For example, when the tip surface of a grindstone is formed on a plane perpendicular to the central axis, the grindstone is brought into contact with a rotating polishing plate (truing whetstone) by its own weight, so that the upper surface of the polishing plate is shaped. Although the transfer was made to the grindstone tip, the relative speed with respect to the polishing dish was not uniform over the entire area of the grindstone tip, so the top shape of the polishing dish could not be accurately transferred to the grindstone tip. In addition, since the grinding stone only contacted the circumference of the same radius on the upper surface of the polishing plate, only the circumferential portion in contact with the grinding stone was worn out, and the upper surface of the polishing plate to be transferred to the tip surface of the grinding wheel was worn. The shape was lost, and as a result, there was a problem that the tip surface of the grindstone did not become an accurate plane.

In the case where the vertical cross-sectional shape of the edge of the grindstone is an arc shape, a method for performing such truing with high accuracy has not been established, and the grindstone is monitored by using a precise shape sensor to monitor the shape. Truing had to be performed while finely adjusting the angle of the truing whetstone. Therefore, it has been almost impossible to satisfy the circularity of the arc shape of the edge in the vertical section including the central axis at the micron level.

[0008] The first object of the present invention is to provide a truing whetstone without changing the shape of the tip surface thereof in view of the above problems.
An object of the present invention is to provide a grindstone truing method capable of forming the tip shape of a grindstone into a shape that exactly corresponds to the tip surface shape of a truing grindstone.

Heretofore, truing of a grindstone has been performed before it is attached to a curve generator. Therefore, even if the shape of the tip of the grindstone can be trued with high precision using a special truing machine or the like, when the grindstone is removed from the truing machine and attached to the curve generator, inevitable core runout will occur. However, at the time of truing, the accuracy was still reduced.

[0010] A second object of the present invention is to solve this problem,
A grinding wheel truing method that does not cause the center deviation of the grinding wheel to the grinding wheel spindle of the curve generator,
To provide.

[0011]

According to a first aspect of the present invention, there is provided a grinding wheel truing method, comprising: rotating a columnar or cylindrical grinding wheel around its central axis to polish the grinding wheel. A truing wheel having a rotationally symmetrical tip surface for rotating the truing grindstone around its axis of symmetry, and the edge of the grindstone tip surface is in contact with the truing grindstone tip surface in a state in which the edge of the grindstone is in contact with the truing grindstone. As the edge moves along the tip surface of the truing whetstone, while relatively maintaining the center axis of the whetstone and the symmetry axis of the truing whetstone in parallel, relatively moving the whetstone and the truing whetstone It is characterized by.

[0012] According to a second aspect of the present invention, there is provided a whetstone truing method.
The tip surface of the truing grindstone of claim 1 is specified by having a shape having an arcuate portion in a cross section including the axis of symmetry.

[0013] The grinding stone truing method according to claim 3 is characterized in that:
The edge of the tip surface of the grinding stone according to claim 1 or 2 is specified as being the outer edge of the tip surface of the grinding stone. Claim 4
In the grinding stone truing method described above, the edge of the leading end surface of the grinding wheel according to claim 2 is specified as being the inner edge of the leading end surface of the cylindrical grinding wheel.

[0014] A grinding stone truing method according to claim 5 is characterized in that:
The truing whetstone according to any one of claims 1 to 4 is specified by the fact that the tip surface is spherical. The truing method according to claim 6 is characterized in that the tip surface of the truing whetstone according to any one of claims 1 to 4 is a hemispherical surface.

[0015] According to a seventh aspect of the present invention, there is provided a whetstone truing method.
The edge of the tip surface of the truing whetstone according to any one of claims 1 to 4 is specified as being formed as an annular surface.

[0016] The grinding stone truing method according to claim 8 comprises:
The tip surface of the truing whetstone according to any one of claims 1 to 4, wherein the vicinity of the edge is perpendicular to the symmetry axis, and the vicinity of the symmetry axis is substantially parallel to the symmetry axis. By being a surface, it is specified.

A truing method of a grinding stone according to claim 9 is characterized in that:
It has been specified that the tip surface of the truing whetstone of claim 1 is a plane orthogonal to the axis of symmetry. The grinding stone truing method according to claim 10 is the method according to claims 1 to 9.
The edge of the tip surface of the grinding stone in any of the above is moved along the tip surface of the truing whetstone from a position contacting the rotation center of the tip surface of the truing whetstone to a position contacting the peripheral edge of the tip surface. That is what was specified.

According to an eleventh aspect of the present invention, there is provided a grinding stone truing method according to any one of the first to ninth aspects, wherein the edge of the tip end surface of the grinding stone is moved from a position in contact with a peripheral edge of the tip end surface of the truing wheel to the center of rotation of the tip end surface. The truing wheel is moved along the tip surface of the truing whetstone to a position where it contacts the truing wheel.

According to a twelfth aspect of the present invention, there is provided a grinding wheel truing method according to any one of the first to eleventh aspects, wherein the moving speed of the edge of the leading end surface of the grinding stone along the leading end surface of the truing whetstone is uniform. It was done.

According to a thirteenth aspect of the present invention, there is provided a grinding stone truing method according to any one of the first to twelfth aspects, wherein the edge of the tip end surface of the grinding stone is in contact with the tip end surface of the truing stone, and the truing stone is further removed. Is cut into the above-mentioned grindstone.

According to a fourteenth aspect of the present invention, there is provided a grinding stone truing method, comprising: forming a columnar or cylindrical grinding wheel having a tip edge whose section including a central axis is rounded in an arc shape; Rotate around the central axis, rotate the cylindrical truing whetstone whose tip surface is a hemispherical surface around the symmetry axis, and the edge of the whetstone tip surface contacts the tip surface of the truing whetstone. In such a state that the edge of the tip of the grinding wheel moves along the tip of the truing whetstone, while maintaining the center axis of the whetstone and the symmetry axis of the truing whetstone parallel, The truing whetstone is relatively moved.

According to a twelfth aspect of the present invention, there is provided a grinding stone truing method, wherein when the grinding wheel and the truing whetstone are relatively moved, a center of curvature of the leading edge of the leading edge of the grinding wheel in a cross section including the central axis is provided. It is specified by keeping a constant distance between the center of curvature of the hemispherical surface forming the tip end surface of the truing whetstone.

In order to solve the first and second problems, a grinding wheel truing method according to claim 16 rotates a grinding wheel spindle for rotating a columnar or cylindrical grinding wheel and a workpiece by the grinding wheel. A grinding wheel truing method using a curve generator having a work spindle, wherein the grinding wheel is attached to the grinding wheel spindle and rotated about its central axis by the grinding wheel spindle, and a rotationally symmetrical tip surface for polishing the grinding wheel. A truing whetstone having the following is attached to the work spindle and the work spindle is rotated around the axis of symmetry, and the edge of the tip surface of the whetstone is in contact with the tip surface of the truing whetstone. The edge of the surface moves along the tip of the truing whetstone So that the while parallel keeping a symmetry axis of the central shaft and the truing grindstone of the grinding wheel, and wherein the relatively moving the said grinding wheel and said truing grindstone.

A truing wheel truing method according to a seventeenth aspect is characterized in that the tip surface of the truing whetstone according to the sixteenth aspect has a shape having an arcuate portion in a cross section including the axis of symmetry.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

[0026]

Embodiment 1 First, a first embodiment of the present invention will be described. The grinding stone truing method according to the present embodiment is configured such that, on a curve generator for performing a grinding process using a cup grinding stone, the cup grinding stone is formed such that the vertical cross-sectional shape of the outer edge of the cup grinding stone attached to the tip of the grinding stone spindle becomes an arc shape. Truing. <Structure of Curve Generator> First, the structure of a curve generator used in the grinding stone truing method according to the present embodiment will be described.

FIG. 1 is a plan view showing the structure of the curve generator. As shown in FIG. 1, the curve generator includes a work part A and a grindstone part B. This work part A is placed on a bed (not shown) on which the whole work part A and the grindstone part B are stacked, in the X direction (the horizontal direction in FIG. 1).
And X table 2 to slide, the rotating shaft (workpiece axis) l ₁ and the workpiece spindle 11 which is fixed on the X table 2 in the X-direction, a work spindle so as to rotate about the workpiece axis l ₁ And the workpiece holder 3 attached to the tip of the workpiece 11. And
A cylindrical GC (green carborundum) grindstone 8 is attached to the workpiece holder 3 at the time of truing, and a workpiece (not shown) is attached at the time of machining.

On the other hand, the grindstone portion B has a Y table 5 that slides in the Y direction (up and down direction in FIG. 1) on a bed (not shown) on which the entire work portion A and the grindstone portion B are mounted. A θ table 6 that rotates about a θ axis oriented in the Z direction (a direction orthogonal to the X direction and the Y direction), and its rotation axis (grinding wheel axis) l ₂ is fixed on the θ table 6 perpendicular to the θ axis. a grindstone spindle 12, which is, from the attached tapered shape of the grindstone holder 7 for the tip of the grindstone spindle 12 so as to rotate about the wheel spindle l _2, is constructed. At the tip of the grindstone holder 7, a cup grindstone C having a bottomed cylindrical shape is detachably fixed. From these grindstone holder 7 and the cup grindstone C, and a wheel spindle l ₂ coaxially. The outer edge of the tip of the cup grindstone C functions as an action point when processing a spherical concave surface on the workpiece, and the inner edge of the tip functions as an action point when processing a spherical convex surface on the workpiece. Hereinafter, the outer edge of the tip of the cup grindstone C is referred to as “outer edge”, and the inner edge of the tip is referred to as “inner edge”.

The grinding wheel axis l _2, which is the rotation axis of the cup grinding wheel C, can cross the work axis l ₁ at any angle by the rotation of the θ table 6. For example, when a workpiece is machined, they intersect at an angle corresponding to the radius of curvature of a spherical surface formed on the workpiece. However, at the time of truing, the grindstone shaft l ₂ is in parallel with the workpiece axis l _1. <Structure of Cylindrical GC Grindstone> Next, the structure of the cylindrical GC grindstone 8 used as a truer (truing grindstone) when truing the edge of the cup grindstone C will be described.
The columnar GC grindstone 8 is made of a GC grindstone generally used as a dresser (for sharpening) of the grindstone, and has a columnar shape having a completely hemispherical tip surface. Accordingly, in the longitudinal section including the central axis, that is, the target axis, the distal end surface shape of the columnar GC grinding stone 8 includes an arc-shaped portion. The tip surface has a rotationally symmetric shape with the central axis of the columnar GC grinding wheel 8 as a symmetric axis.

The particle size of the silicon carbide abrasive grains constituting the columnar GC grinding stone 8 is determined by the cup grinding stone C to be trued.
Are almost the same or slightly coarser than the grain size of the diamond abrasive grains constituting

The diameter of the columnar GC grindstone 8 is equal to or less than the outer diameter of the cup grindstone 8 to be trued. In the following description, the center of the tip of the cylindrical GC grindstone 8 is referred to as “vertex”, and the boundary between the spherical surface at the tip surface and the cylindrical surface at the peripheral surface is referred to as “peripheral edge”. <Trueing Method> Next, the steps of the truing method according to the present embodiment will be described.

Firstly, in preparation, the cup grindstone C is truing target, the center axis thereof so as to match the wheel spindle l _2, attached to the grindstone holder 7. And
The tip surface is trued to be perpendicular with respect to the grinding wheel axis l _2. Specifically, the grinding wheel spindle 12 is rotated at high speed, with which allusion stick grindstone toward the long axis in a direction perpendicular to the grinding wheel axis l ₂ (not shown) on the distal end surface of the cup grindstone C, the The stick whetstone is reciprocated in its long axis direction. Note that the stick whetstone may be attached to the work holder 3 in a rotation stopped state. In this case, the X table 2 and the Y table 5 are NC-controlled, the stick table is cut by the X table 2, and the cup table C is reciprocated in the Y direction by the Y table 5. By the above truing, the outer edge of the cup grindstone C, in cross-section including the wheel spindle l _2, a sharp right angle.

Next, by appropriately moving the X table 2 and the Y table 5, the outer edge γ of the cup grindstone C is obtained.
Is brought into contact with the apex of the cylindrical GC grinding wheel 8 (see FIG. 2). Then, in this state, the cup grindstone C is rotated at a high speed by the grindstone spindle 12, and the columnar GC grindstone 8 is rotated at a low speed by the work spindle 11.
Start C control.

In this NC control, the X table 2
The cylindrical GC grinding wheel 8 is continuously provided with a notch of 5 to 30 μm from a state in contact with the cup grinding wheel C (FIG. 1).
Arrow β). At the same time, the X table 2 and the Y table 5 synchronize with each other so that the outer edge γ of the cup grindstone C relatively moves at a constant speed from the apex to the periphery along the tip end surface shape of the cylindrical GC grindstone 8. , Cup whetstone C
And the columnar GC grinding wheel 8 is relatively moved. The relative positions of the cup grindstone C and the columnar GC grindstone 8 during the relative movement are shown in FIGS. 3 and 4 (however, FIG. 4 shows a state after FIG. 3). FIG. 5 shows a state where the outer edge γ of the cup grindstone C has reached the peripheral edge of the columnar GC grindstone 8 after the completion of the relative movement.

The arrow v in each figure indicates the relative movement direction of the cup grindstone C with respect to the cylindrical GC grindstone 8 at that time, and the direction is the same as the cylindrical GC grindstone at the point of contact with the outer edge γ. 8 coincides with the inclination direction of the tip end surface. The arrow α in each drawing indicates the direction in which the cylindrical GC grinding stone 8 acts on the outer edge γ (the direction in which friction is applied) at that time, and the center O of the tip hemispherical shape of the cylindrical GC grinding stone 8 is shown. This line coincides with the line connecting ₁ and the outer edge γ. Therefore, the direction α in which friction is applied to the outer edge γ is determined by the movement of the outer edge γ and the grinding wheel axis l _2.
From the direction of 0 degrees to the direction of 90 degrees.

As can be understood from FIGS. 2 to 5, since the tip of the columnar GC grinding stone 8 is a perfect hemisphere, the inclination direction of the surface thereof is such that the work axis l extends from the top to the periphery. gradually changes from the direction perpendicular to the workpiece axis l ₁ to a direction parallel to _1. Accordingly, when the action point γ is moved from the vertex to the peripheral edge, the inclination direction of the surface of the columnar GC grinding stone 8 in contact with the outer edge γ is changed from a direction parallel to the tip end surface of the cup grinding stone C to a direction parallel to the outer peripheral surface. And gradually change. Since the outer edge γ is polished so as to be a surface in the same direction as the surface of the cylindrical GC grinding stone 8 in contact with the outer edge γ,
Grinding is applied to the outer edge γ from the direction of the arrow α that changes in an angle range of 90 degrees as the inclination direction of the surface of the cylindrical GC grinding stone 8 in contact changes. In all directions is transferred.

Therefore, the outer edge γ of the cylindrical GC grinding stone 8 is
Relative along the shape from the top to the periphery at a constant speed
When it moves, the vertical section of the tip of the cylindrical GC grinding wheel 8 (workpiece
Axis l ₁, Including the same in the following), that is, 90 degrees
The arc shape of the opening angle is reduced and the vertical section of the outer edge γ
(Wheel axis l_Two(The same applies hereinafter).
As a result, the vertical cross-sectional shape of the outer edge γ has an opening angle of 90 degrees.
It is processed into an accurate arc shape. This first time
Cross section of cup grinding wheel C at the time when rouing is completed
The shape is indicated by the reference symbol I in FIG. In addition, outside
The edge γ is, on the contrary to the above, the cylindrical GC grinding wheel 8.
Relative to the vertex from the periphery along the shape at a constant speed
May be moved.

Since the columnar GC grinding wheel 8 is softer than the cup grinding wheel C, when the first truing is completed, the total length of the columnar GC grinding wheel 8 is shortened by almost the cut amount. However, the tip surface of the columnar GC grinding wheel 8 is worn evenly over the entire surface, so that the shape of the tip remains a hemisphere.

In the second and subsequent truing operations, the center of curvature O ₂ of the arc in the longitudinal section of the outer edge of the cup grindstone C machined as a result of the previous truing operation is set to the work axis l _1.
The tip surface of the cup grindstone C is brought into contact with the apex of the columnar GC grindstone 8 in a state where it is positioned on an extension of. Then, similarly to the first truing, the NC control is started.

However, NC in the second and subsequent truing
In the control, the X-table 2 and the Y-table 5 are provided with the center of curvature O ₁ of the tip hemispherical shape of the columnar GC grinding wheel 8 and the center of curvature O ₂ of the arc shape formed on the longitudinal section of the outer edge of the cup grinding wheel C. While maintaining a constant distance (a distance obtained by adding the radius of curvature of the hemispherical tip of the cylindrical GC grinding wheel 8 and the radius of curvature R of the arc formed in the longitudinal section of the cup grinding wheel C), the cylindrical GC grinding wheel 8 and the cup The point of contact with the grinding wheel C is cylindrical GC
The cup grindstone C and the columnar GC grindstone 8 are relatively moved so as to relatively move at a constant speed from the vertex to the periphery along the shape of the tip surface of the grindstone 8 (at the time when the first truing is started). Is the center of curvature O ₂ of the arc shape in the cross section of the outer edge of the cup grinding wheel C and the columnar GC
If it is considered that the contact point between the grindstone 8 and the cup grindstone C overlaps at the same position γ, the condition in the first truing can be generalized by the condition in the second and subsequent truing).

By repeating the truing described above,
The radius of curvature R of the arc formed on the longitudinal section of the outer edge of the cup grindstone C gradually increases as shown in FIG. 6 (the reference symbol V in FIG. 6 indicates the state at the end of five truing operations). , And the reference symbol X indicates the state at the end of 10 truing operations.) Even if the radius of curvature R is increased in this manner, the vertical cross-sectional shape of the outer edge of the cup grindstone C is similar to one side (vertex to peripheral edge) of the vertical cross-sectional shape of the tip of the cylindrical GC grindstone 8, and its arc shape Has an opening angle of 90 degrees. Then, when the radius of curvature R of the circular arc formed on the longitudinal section of the outer edge γ of the cup grindstone C reaches the target value, the entire truing is completed.

When the entire truing is completed in this way, the workpiece is processed. At this time,
Only the columnar GC grindstone 8 is replaced with the workpiece, and the trued cup grindstone C is used without being removed from the grindstone holder 7. Therefore,
No dedicated truing machine is used, and there will be no center runout associated with the attachment and detachment of the cup grindstone C.

[0043]

EXAMPLE A cup grindstone C having a diamond grain size of 800 was trued according to the grindstone truing method according to the present embodiment, and the radius of curvature R of the arc shape in the longitudinal section of the outer edge γ was measured. When measuring, use a cup grindstone C
Was tilted by 45 degrees with the θ table 6 and the shape of the outer edge γ was transferred to a material such as carbon or delrin (polyacetal), and then the shape was measured.

The measured radius of curvature R is 0.825 mm
And its roundness was PV 2 μm including roughness. Therefore, excluding the roughness component, the roundness is about 0.5 μm
It seems to have reached the level of. According to the truing method according to the present embodiment, this degree of roundness can be easily reproduced.

The above description has been made in connection with the case where the outer edge γ of the cup grindstone C is trued. However, if the outer diameter of the columnar GC grindstone 8 is smaller than the inner diameter of the cup grindstone C, according to the present embodiment, the cup grindstone is formed. It is also possible to truing the inner edge of C.

[0046]

[Embodiment 2] Fig. 7 shows a cylindrical GC grinding wheel 1 used in a truing method according to a second embodiment of the present invention.
8 is shown. The outer edge of the tip end surface of the cylindrical GC grinding wheel 18 is
The vertical cross-sectional shape is formed so as to form a part of a ring-shaped surface having an arc shape with an opening angle of 90 degrees. Also, near the center of its tip surface is formed as a work axis l ₁ perpendicular planes.

The steps of the truing method according to the present embodiment are exactly the same as those of the first embodiment, and a description thereof will be omitted. Also in the present embodiment, if the outer edge γ of the cup grinding wheel C is relatively moved at a constant speed from the center point to the periphery along the shape of the cylindrical GC grinding wheel 18, the cross section of the outer edge γ of the cup grinding wheel C The shape becomes an arc shape with an opening angle of 90 degrees.

[0048]

Third Embodiment FIG. 8 shows a columnar GC grinding wheel 2 used in a truing method according to a third embodiment of the present invention.
8 is shown. The distal end surface of the cylindrical GC grindstone 28, near the center portion thereof with pointed so as to be substantially parallel to the workpiece axis l _1, has spread so that at its periphery the workpiece axis l ₁ and a plane perpendicular . And the vertical cross-sectional shape between the center and the periphery is an arc shape depressed inward.

The steps of the truing method according to the present embodiment are exactly the same as those of the first embodiment, and a description thereof will be omitted. Also in the present embodiment, if the outer edge γ of the cup grindstone C is relatively moved at a constant speed from the center point to the periphery along the shape of the cylindrical GC grindstone 28, the cross section of the outer edge γ of the cup grindstone C is obtained. The shape becomes an arc shape with an opening angle of 90 degrees.

[0050]

Embodiment 4 FIG. 9 shows a columnar GC grinding wheel 3 used in a truing method according to a fourth embodiment of the present invention.
8 is shown. The distal end surface of the columnar GC grinding wheel 38 is processed as a circular flat surface, and the boundary (peripheral edge) between the distal end surface and the outer peripheral surface is processed into a shape that forms the inner surface of the annular surface.
The inner surface of the ring surface and the front end surface form a right-angled edge, and the inner surface of the ring surface and the outer peripheral surface form a right-angled edge.

The steps of the truing method according to the present embodiment are exactly the same as those of the first embodiment, and a description thereof will be omitted. Also in the present embodiment, the outer edge γ of the cup grinding wheel C is constant from the edge with the tip surface to the edge with the peripheral surface along the shape of the inner surface of the annular surface formed on the periphery of the cylindrical GC grinding wheel 38. If relatively moved at the speed, the cup grinding wheel C
Has a 90 ° open angle arc-shaped cross section.

[0052]

Embodiment 5 Next, a fifth embodiment of the present invention will be described. The grinding wheel truing method according to the present embodiment, on a curve generator that performs grinding using a cylindrical grinding wheel, the tip surface of the cylindrical grinding wheel attached to the grinding wheel spindle tip as a plane perpendicular to the center axis of the cylindrical grinding wheel. In addition to truing, the outer peripheral surface of the cylindrical grindstone is trued as a cylindrical surface coaxial with the center axis of the cylindrical grindstone. <Structure of Curve Generator> First, the structure of a curve generator used in the grinding stone truing method according to the present embodiment will be described.

FIG. 10 is a side view of the curve generator. As shown in FIG. 10, the curve generator in the present embodiment is different from that of the first embodiment in the moving direction of the X table 42 on which the work spindle 46 is mounted (the X direction, ie, the horizontal direction in FIG. 10). ) And the direction of the rotation axis (work axis l ₁ ) of the work spindle 46 (the Y direction, ie, the vertical direction in FIG. 10) are orthogonal to each other. Hereinafter, the detailed configuration will be described.

On the upper surface of the fixed table 40 serving as the base of the entire curve generator, two rails 41 (only the front one is shown in FIG. 10) oriented in the X direction are arranged in a direction perpendicular to the paper surface. Is fixed. An X table 42 slidable only in the X direction along the two rails 41, 41 is provided between the two rails 41, 41.
The rails 41, 41 are engaged so as not to fall off. In addition, a female screw hole penetrating in the X direction is formed inside the X table 42.

A plate-like stay 43 whose longitudinal direction is perpendicular to the paper surface of FIG. 10 is stretched between one ends (left ends in FIG. 10) of both rails 41, 41.
A screw shaft 44 screwed into the female screw hole of the X table 42 is rotatably penetrated through the stay 43. The screw shaft 44 is driven to rotate by a motor 45 supported on the outer surface of the stay 43. Accordingly, the motor 45 causes the screw shaft 4
By appropriately rotating the table 4, the X table 42 can be slid in the X direction along the rails 41, 41 as appropriate.

[0056] the upper surface of the X table 42, the rotation axis (workpiece axis) l ₁ in a state directed in the Y direction, the workpiece spindle 46 is fixed. This work spindle 4
6 is a workpiece holder 47 attached to the tip of the workpiece holder 47.
Is rotated about the work axis l ₁ . A polishing plate 48 is fixed to the workpiece holder 47 detachably during truing, and a workpiece (not shown) is detachably fixed during processing.

On the other hand, the rail 41 on the far side in FIG.
(Not shown), on the upper surface of the fixed table 40, two parallel rails 55, 5 facing in the Y direction.
5 are arranged and fixed in the X direction. Between these rails 55, 55, along both rails 55, Y
A Y table 49 slidable only in the direction is engaged with the two rails 48, 48 in a state where it cannot be dropped off. In addition, a female screw hole penetrating in the Y direction is formed inside the Y table 49.

A plate-like stay 50 is stretched between the ends (upper ends in FIG. 10) of both rails 55, 55. A screw shaft 51 screwed into a female screw hole of the Y table 49 is rotatably penetrated through the stay 50. The screw shaft 51 is connected to the stay 5
It is directly connected to a handle 52 attached to the upper surface of the "0". Therefore, if the screw shaft 51 is appropriately rotated by the handle 52, the Y table 49 can be slidably moved in the Y direction along both the rails 55, 55.

On the surface of the Y table 49 (the surface facing the near side in FIG. 10), the grindstone spindle 53 is rotatable around the θ axis in the Z direction (a direction orthogonal to the X direction and the Y direction). Is attached. The grindstone spindle 53 includes a grindstone holder 54 attached to the tip thereof,
rotation axis perpendicular to θ-axis is rotated around the (wheel spindle) l _2. At the tip of the grindstone holder 54, a cylindrical grindstone G is provided.
It is fixed to the wheel spindle l ₂ coaxially.

The grinding wheel shaft l _2, which is the rotation axis of the columnar grinding wheel G, can cross the work shaft l ₁ at any angle by the rotation of the grinding wheel spindle 53 itself with respect to the Y table 49. <Structure of Polishing Dish> Next, a truer (truing whetstone) for truing the tip end surface and outer peripheral surface of the cylindrical whetstone G
The structure of the polishing plate 48 used as the above will be described. The polishing plate 48 is made of cast iron, stainless steel, or a copper alloy, and has a disk shape as shown in FIG. Therefore, the upper surface (tip surface) for polishing the cylindrical grindstone G has a rotationally symmetric shape (that is, a circular plane) with the central axis of the polishing plate 48 itself as a target axis. <Trueing Method> Next, the steps of the truing method according to the present embodiment will be described.

[0061] First, as a preparation stage, a cylindrical grinding wheel G is trued object, in a state of being matched with the central axis wheel spindle l _2, it is fixed to the grindstone holder 54. Similarly, the polisher 48, in a state of being matched its central axis (target axis) to the work axis l _1, is fixed to the workpiece holder 47 of the work spindle 46. At this time, an abrasive is applied to the upper surface 48a of the polishing plate 48.

[0062] Then, the grinding wheel spindle 53 itself rotates relative to the Y table 49, the wheel spindle l ₂ accurately directed to the Y direction. Next, the motor 45 is rotated to rotate the X table 4.
2 moves the causes intersect the outer periphery of the polisher 48 between the wheel spindle l _2. Next, by rotating the handle 52, the Y table 49 is moved toward the fixed table 40, and the tip end surface of the cylindrical grindstone G is pressed against the upper surface 48a of the polishing plate 48 (see FIG. 10).

After the above preparation is completed, the columnar grindstone G is rotated at a low speed by the grindstone spindle 53, and the polishing plate 48 is rotated at a high speed by the work spindle 46. Further, the X-table 42 is reciprocated by the NC control of the motor 45, whereby the columnar grindstone G is repeatedly reciprocated relatively between the center and the periphery of the upper surface 48a of the polishing plate 48. Truing working tip surface of the cylindrical grinding wheel G which is carried out in this way, the shape of the upper surface 48a of the polishing dish 48 (i.e., a plane shape perpendicular to the wheel spindle l ₁₎ is completely the front end surface of the cylindrical grinding wheel G It continues until it is transferred to.

During the truing operation, the handle 52 must be appropriately adjusted so that the cutting amount of the cylindrical grindstone G into the polishing plate 48 becomes a predetermined amount. Specifically, when the truing operation proceeds and the tip surface of the cylindrical grindstone G and the upper surface 48a of the polishing plate 48 are cut, the Y table 49 is moved toward the fixed table 40 by the cut amount. That is, the cut amount is adjusted to be constant.

[0065] Truing work continued result, the polisher 48 of the upper surface 48a of the shape (i.e., a plane shape perpendicular to the workpiece axis l ₁₎ is completely transferred to the distal end surface of the cylindrical grinding wheel G, cylindrical grinding wheel G When the distal end surface of is a plane that is perpendicular to the wheel spindle l _2, by moving the Y table 49 toward the stay 50 together pull the cylindrical grinding wheel G from polisher 48, and stops the motor 45 and the spindle 46, 53 . Next, the grindstone spindle 53 itself is rotated 90 degrees clockwise in FIG. Next, the X table 42 is moved by rotating the motor 45 so that the vicinity of the peripheral edge of the polishing plate 48 is located immediately below the tip of the cylindrical grindstone G. Next, by rotating the handle 52, the Y table 4
9 is moved toward the fixed table 40, and the outer peripheral surface near the tip of the cylindrical grindstone G is pressed against the upper surface 48a of the polishing plate 48 (see FIG. 11).

After the above preparation is completed, the columnar grindstone G is rotated at a low speed by the grindstone spindle 53, and the polishing plate 48 is rotated at a high speed by the work spindle 46. The X-table 42 is reciprocated by the NC control of the motor 45, so that the periphery of the upper surface 48a of the polishing plate 48 is repeatedly reciprocated between the tip end and the base end of the cylindrical grindstone G (see FIG. 12). Such truing operations of the outer peripheral surface of the cylindrical grinding wheel G which is carried out in, until the outer peripheral surface of the cylindrical grinding wheel G is a cylindrical surface of the wheel spindle l ₂ coaxially, continues. During this truing operation, the handle 52 must be appropriately adjusted so that the cutting amount of the cylindrical grindstone G into the polishing plate 48 is a predetermined amount.

As a result of continuing the truing operation, when the outer peripheral surface of the cylindrical grindstone G becomes a cylindrical surface coaxial with the grindstone axis l ₂ ,
The Y table 49 is moved toward the stay 50 to separate the cylindrical grindstone G from the polishing plate 48, and the motor 45 and the spindles 46 and 53 are stopped. This allows
Since all the truing operations are completed, the polishing plate 48 is replaced with a workpiece, and the workpiece is subsequently ground. At this time, the truing cylindrical whetstone G
Is used as it is without being removed from the grindstone holder 54. Therefore, a dedicated truing machine is not used, and there is no occurrence of center runout due to attachment and detachment of the cylindrical grindstone G. As described above, according to the grindstone truing method according to the present embodiment, when the tip surface of the cylindrical grindstone G is trued, not only the polishing plate 48 but also the cylindrical grindstone G itself rotates. The tip surface of the cylindrical grindstone G is trued in a state close to the state of the grinding operation. As a result, the tip end surface of the cylindrical grindstone G is polished evenly over the entire area. During truing, the polishing plate 48 is reciprocated in the X direction so that the columnar grindstone G relatively moves back and forth between the center and the periphery of the upper surface 48a of the polishing plate 48. Therefore, the polishing plate 48
Is polished evenly over its entire area, so that its shape does not collapse. On the other hand, when truing the outer peripheral surface of the cylindrical grindstone G, the cylindrical grindstone G
There therefore is polished in a state that is rotating about a grinding wheel axis l _2, the cylindrical accuracy of the outer peripheral surface is improved. As a result, an ideal tool shape can be obtained. In addition, according to the present embodiment, the cutting amount of the cylindrical grindstone G into the polishing plate 48 can be arbitrarily adjusted by appropriately rotating the handle 52, so that the truing amount can be accurately determined. As a result, for example, even when the columnar grindstone G once used is re-trued, the cylindrical grindstone G is not unnecessarily worn.

[0068]

According to the grinding stone truing method of the present invention, the shape of the tip surface of the truing grindstone can be maintained without breaking.
The tip shape of the grindstone can be formed into a shape that exactly corresponds to the tip surface shape of the truing grindstone.

Further, according to the configuration of claim 16, since the accuracy does not decrease due to the attachment / detachment of the grindstone, high-precision machining can be performed using the curve generator to which the grindstone is mounted.

[Brief description of the drawings]

FIG. 1 is a plan view of a curve generator used in a truing method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a cylindrical GC grinding wheel and a cup grinding wheel during truing.

FIG. 3 is a diagram showing a positional relationship between a cylindrical GC grinding wheel and a cup grinding wheel during truing.

FIG. 4 is a view showing a positional relationship between a cylindrical GC grinding wheel and a cup grinding wheel during truing.

FIG. 5 is a diagram showing a positional relationship between a cylindrical GC grinding wheel and a cup grinding wheel during truing.

FIG. 6 is an explanatory view of the shape of a cup grinding wheel after truing.

FIG. 7 is a side view of a columnar GC grinding wheel used in a second embodiment of the present invention.

FIG. 8 is a side view of a cylindrical GC grinding wheel used in a third embodiment of the present invention.

FIG. 9 is a side view of a columnar GC grinding wheel used in a fourth embodiment of the present invention.

FIG. 10 is a side view of a curve generator used in a truing method according to a fifth embodiment of the present invention.

11 is a side view of the curve generator of FIG. 10 when truing the outer peripheral surface of the cylindrical grinding wheel.

FIG. 12 is a perspective view of a polishing dish and a grinding wheel spindle in the state of FIG. 11;

[Explanation of symbols]

8, 18, 28, 38 Cylindrical GC grinding wheel 11, 46 Work spindle 12, 53 Grinding wheel spindle 48 Polishing dish C Cup grinding wheel G Cylindrical grinding wheel l ₁ Work shaft l ₂ Grinding wheel shaft

Continuation of the front page (72) Inventor Satoshi Hiyama 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd.

Claims (17)

[Claims] 1. A truing grindstone having a rotationally symmetrical tip surface for polishing said grindstone is rotated about a symmetric axis by rotating a cylindrical or cylindrical grindstone about its central axis. The center axis of the whetstone, such that the edge of the tip surface of the grinding wheel moves along the tip surface of the truing whetstone while the edge of the tip surface of the whetstone is in contact with the tip surface of the truing whetstone. A grindstone truing method, wherein the truing grindstone and the truing grindstone are relatively moved while keeping the symmetry axis of the truing grindstone parallel. 2. The method according to claim 1, wherein the tip surface of the truing grindstone has a shape having an arcuate portion in a cross section including the axis of symmetry. 3. The grinding stone truing method according to claim 1, wherein the edge of the tip surface of the grinding stone is an outer edge of the tip surface of the grinding stone. 4. The grinding stone truing method according to claim 2, wherein the edge of the tip surface of the grinding wheel is an inner edge of the tip surface of the cylindrical grinding wheel. 5. A grinding stone truing method according to claim 1, wherein the tip surface of the truing grindstone is spherical. 6. The grinding stone truing method according to claim 1, wherein a tip surface of the truing grindstone has a hemispherical surface. 7. A grinding stone truing method according to claim 1, wherein an edge of a tip end surface of said truing grindstone is formed as an annular surface. 8. The tip surface of the truing whetstone is a pointed surface such that the vicinity of the edge is perpendicular to the axis of symmetry and the portion near the axis of symmetry is substantially parallel to the axis of symmetry. The grinding stone truing method according to any one of claims 1 to 4, wherein: 9. The truing wheel according to claim 1, wherein a tip surface of the truing wheel is a plane orthogonal to the axis of symmetry.
The described grinding stone truing method. 10. The edge of the tip of the truing wheel along the tip of the truing wheel from a position in contact with the center of rotation of the tip of the truing wheel to a position in contact with the periphery of the tip. The grinding stone truing method according to any one of claims 1 to 9, wherein the grinding wheel is moved. 11. The edge of the tip of the truing wheel along the tip of the truing wheel from a position in contact with a peripheral edge of the tip of the truing wheel to a position in contact with a rotation center of the tip. The grinding stone truing method according to any one of claims 1 to 9, wherein the grinding wheel is moved. 12. The grinding wheel truing method according to claim 1, wherein the moving speed of the edge of the leading end surface of the grinding wheel along the leading end surface of the truing whetstone is a uniform speed. . 13. The truing wheel is further cut into the grindstone from the state where the edge of the tip surface of the grindstone is in contact with the tip surface of the truing grindstone. The truing method of a grinding stone according to the above. 14. A cylindrical or cylindrical grindstone having a tip edge whose cross section including the center axis is rounded in an arc shape is rotated about the center axis, and the tip surface is a hemispherical column. The truing whetstone is rotated about its axis of symmetry, and the edge of the tip surface of the whetstone contacts the tip surface of the truing whetstone while the edge of the tip surface of the whetstone contacts the tip surface of the truing whetstone. The truing wheel and the truing wheel are moved relative to each other while keeping the center axis of the grinding wheel and the symmetric axis of the truing wheel parallel to each other so as to move along. 15. When the grindstone and the truing grindstone are relatively moved, the center of curvature of the tip edge in a cross section including the central axis of the grindstone and a hemispherical surface forming the tip face of the truing grindstone are provided. The method according to claim 14, wherein the distance from the center of curvature is kept constant. 16. A grindstone truing method using a curve generator having a grindstone spindle for rotating a cylindrical or cylindrical grindstone and a work spindle for rotating a workpiece to be machined by the grindstone, wherein the grindstone is the grindstone. A truing whetstone having a rotationally symmetrical tip surface for polishing the whetstone is attached to the work spindle, and is attached to the work spindle. So that the edge of the tip of the grinding wheel moves along the tip of the truing whetstone in a state where the edge of the tip of the whetstone is in contact with the tip of the truing whetstone. Parallel the center axis of the grinding wheel and the axis of symmetry of the truing wheel Keeping while, grindstone truing method for causing relative movement of said grinding wheel and said truing grindstone. 17. The grinding wheel truewing method according to claim 16, wherein a tip end surface of the truing grinding wheel has a shape having an arcuate portion in a cross section including the axis of symmetry.