JPH0521707B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a position correction device for an angular grinding machine.

<Prior art> Generally, when grinding the shoulder portion of a workpiece at the same time as grinding the cylindrical portion of the workpiece, an angular grinder having a cylindrical portion grinding surface for grinding the cylindrical portion of the workpiece and a shoulder portion grinding surface for grinding the shoulder end surface is used. Workpieces are processed using an angular grinding machine equipped with a shaped grinding wheel, but in such a grinding machine, the grinding surface of the cylindrical part of the grinding wheel is damaged due to thermal expansion and contraction of the grinding wheel shaft, wear of the grinding surface during grinding, etc. When the position of the top, which is the intersection of the shoulder grinding surface and the shoulder grinding surface, is displaced, and as a result, the position of the path through which the top of the grinding wheel passes is displaced in a direction parallel to the workpiece axis, the cylindrical part of the workpiece is ground to a predetermined dimension. The position of the shoulder grinding surface is not constant when the shoulder is ground, making it impossible to accurately grind the shoulder end surface to a predetermined dimension.

For this reason, in conventional angular grinding machines, the depth of cut is set large during truing, as shown in Figure 1, so that the position of the top P of the grinding wheel G in the direction parallel to the grinding wheel axis is always the same after truing. I was trying to position it.

However, when such truing is performed, if an appropriate depth of cut is given on one ground surface Gb, more of the abrasive grain layer is removed than necessary on the other ground surface Ga, and cubic boron nitride, etc. It is not desirable to perform this type of truing with expensive grinding wheels that use hard material as abrasive grains.
As shown in Fig. 2, it is necessary to perform truing on each of the ground surfaces Ga and Gb with the minimum depth of cut that can remove the waviness of the ground surface. However, when such truing is performed, as shown in Fig. 2, the position of the top P of the grinding wheel G is not constant, and there is a problem that it becomes impossible to grind the shoulder end face of the workpiece to a predetermined dimension with high precision. .

<Purpose of the Invention> Therefore, the present invention is capable of grinding the shoulder end face of a workpiece with high precision even if the position of the top of the grinding wheel is displaced due to thermal expansion and contraction of the grinding wheel shaft. The purpose of this is to enable highly accurate machining of the shoulder end face of a workpiece by limited truing.

<Structure of the Invention> The present invention includes a truing tool provided on a grinding wheel head that holds an angular grinding wheel, and a moving device that moves the truing tool in an axial direction of the angular grinding wheel and in a direction orthogonal to the axis, respectively. , a truing tool control means for driving the moving device according to shape data corresponding to a pair of mutually orthogonal grinding surfaces of the angular grinding wheel, and a truing tool control means for driving the moving device according to shape data corresponding to a pair of mutually orthogonal grinding surfaces of the angular grinding wheel, and truing the position of the pair of grinding surfaces in the cutting direction of the grinding wheel, respectively. A grinding surface detection means for detecting immediately before and after, a position storage means for storing each position of the grinding surface detected by the grinding surface detection means in the cutting direction of the grinding wheel, and a truing stored in the storage means. A first calculation means for calculating a displacement in a direction parallel to the axis of the top grinding wheel where the pair of grinding surfaces intersect from the position detected immediately before and the position detected immediately after the previous truing, and the first calculation means stores the displacement in the storage means. a second calculation means for calculating a displacement in a direction parallel to the workpiece axis at the top where the pair of grinding surfaces intersect from a position detected immediately before truing and a position detected immediately after the previous truing; and the first calculation means. shape data correction means for correcting the shape data in a direction parallel to the grinding wheel axis based on the displacement of the top part in a direction parallel to the grinding wheel axis calculated by the means; and a top part calculated by the second calculation means. The position of the workpiece in the direction of the spindle axis is corrected based on the displacement in the direction parallel to the workpiece axis, so that the path of the grinding wheel passing through the top of the grinding wheel passes through a theoretical passing point set on the workpiece. This is provided with a position correction means for doing so.

This makes it possible to carry out the minimum amount of truing required, and even if the position of the top changes, the relative position of the path that the top passes with respect to the workpiece remains constant, making it possible to accurately align the shoulder end face of the workpiece. Can be grinded.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 3, reference numeral 11 denotes a workpiece table that supports a workpiece W by a headstock 12 and a tailstock 13. It is slidably guided in the Z-axis direction parallel to the axis of the workpiece W, and a feed screw 18 rotated by a servo motor 17 is screwed together. Note that 19 indicates an end face sizing device installed on the bed 10.

On the other hand, behind the bed 10, a grindstone head 20 is guided by guide surfaces 21 and 22 so as to be slidable in the X-axis direction, which runs obliquely at a constant angle θ with respect to the spindle axis OS. A feed screw 25 that is rotated by the grinding wheel is screwed together, and a cylindrical grinding surface Ga parallel to the axis of the workpiece W and a shoulder grinding surface perpendicular to the grinding surface Ga are provided on the front side of the grindstone head 20. An anguilla-shaped grinding wheel G having Gb is mounted on the shaft.

On the other hand, at the rear side of the whetstone head 20, there are shown in FIG.
As shown in FIG. 6, a tracing type truing device 30 is attached with a surface position detection device 40 for detecting the surface position of the grinding surface of the grinding wheel.

As shown in FIG. 4, the truing device 30 is placed on a traverse table 32 that is moved by a cylinder 31 in a direction parallel to the axis of the grinding wheel G, and is moved in a direction perpendicular to the axis of the grinding wheel G by following a template 33. Guide the advancing/retracting platform 35 to advance and retreat, and this advancing/retracting platform 3
A truing head 36 on which a truing vehicle T is mounted is attached to the tip of the truing head 5. The advancing/retracting table 35 is provided with a feed screw 38a that is screwed into a ram portion 37 integral with the truing head 36 and rotated by a servo motor 38. Further, the support base 34 supporting the template 33 has a feed screw 39 rotated by a servo motor 39.
are screwed together, and the position of the grinding wheel G in a direction parallel to the axis of the grinding wheel G is adjusted by rotation of the servo motor 39.

On the other hand, as shown in FIG. 6, the surface position detection device 40 is mounted on a shift table 42 that is shifted by a cylinder 41 by a certain distance in a direction parallel to the axis of the grinding wheel G. A ram 43 that is movable in orthogonal directions and has a contact S attached to its tip is disposed, and a turbo motor 44 is attached to the rear end of this ram 34.
It has a structure in which a feed screw 45 that is rotated by is screwed together. A first contact portion Sa and a second contact portion Sb are formed at the tip of the contactor S, and a first contact portion Sa and a second contact portion Sb are formed with contact surfaces parallel to the ground surfaces Ga and Gb, respectively, and a vibration sensor 46 is formed at the base thereof. is installed,
Contact of the first contact portion Sa and the second contact portion Sb with the grinding wheel G is detected by vibration.

Next, to explain the control circuit, 50 in FIG. 7 is a computer, a memory 51 is connected to this computer 50, and an interface IF connected to the computer 50
1 includes a data input device 52 and a vibration sensor 46.
A contact detection circuit 53 that detects that the contact detector S has contacted the grinding wheel G is connected to a sizing circuit 54 that detects that the output of the end face sizing device 19 has become zero. ing. The interface IF2 also includes servo motors 23, 17,
Drive units DUX, DUZ, DUU, DUV, and DUW are connected to drive the motors 38, 39, and 44, respectively.

Now, when a truing command is given to the computer 50, the computer 50 performs the processing shown in FIG.

Step 1000 Step 116 is a step for detecting the position of each grinding surface Ga and Gb of the grinding wheel G with respect to the origin of the contact, and by distributing pulses to the U axis, 1 in FIG. The contact plate in the state shown by the dotted chain line is moved toward the central axis of the grinding wheel G. And the first contact part Sa
When it comes into contact with the grinding surface Ga, the contact drive device is stopped and the feed amount is stored as MR in step 104. This value of MR represents the position of the ground surface Ga with the origin of the contact S as a reference. After returning the contact to the origin in step 106, in order to measure the position of the grinding surface Gb, the shift cylinder is operated to move the contact S to the right side in the figure, as shown in FIG. 10b. Shift, second
The contact portion Sb is shifted to a predetermined position in the V-axis direction, that is, in a direction parallel to the grindstone axis. Then, in step 110, as described above, after the contact is fed until it makes contact, the amount of feed is stored as NR. This value of NR indicates the position of the grinding surface Gb with respect to the origin of the contact S. Then step 116
At , the contact S is returned to its origin. In this way, the position of the grinding surface immediately before truing is detected as the amount of movement of the contact S.

Next, in step 118, MR-MO, NR-
Calculate NO to find the displacements A and B of the feed amount of each contact portion Sa and Sb. That is, as described later,
MO and NO are the memorized values of the amount of movement of each contact part Sa and Sb until they contact the ground surfaces Ga and Gb, which were measured immediately after the previous truing, and are the values for the step
The values of A and B calculated in 118 are shown in Figure 10 a and b.
As shown in the figure, the displacement of each grinding surface Ga, Gb in the U-axis direction is shown.

Next, in step 120, the displacements △U and △V of the top P of the grinding wheel G in the U-axis direction and the V-axis direction are calculated using the following equations (1) and (2), and using equation (3), The amount of displacement ΔZ in the Z-axis direction parallel to the axis of the workpiece W of the path R through which the top P passes is calculated.

△V=(A-B) sinθ・cosθ...(1) △U=Asin ² θ+Bcos ² θ...(2) △Z=(A-B) cosθ...(3) In addition, Fig. 11 shows the ground surface Ga , Gb radial displacement A, B and each axial displacement △V, △U, △
It is a figure showing the relationship of Z.

When the deviation amounts △V, △U, △Z of the top P of the grinding wheel G in each axial direction are calculated in this way, the process proceeds to step 122.
At this time, the servo motor 39 is operated to move the template 33 by ΔV in the V-axis direction, and the top of the template is moved in accordance with the change in the position of the top P of the grinding wheel G. Next, in step 124,
Drive the servo motor 44 to advance the truing tool by △U+C in the normal direction (U-axis direction), and move the truing wheel T closer to the axis of the grinding wheel G by a certain amount of cut C to the grinding surface Ga. position.

Next, in step 126, the traverse cylinder 41 is operated to move the truing tool T while tracing the template 33 to grind the grinding wheel surfaces Ga and Gb. After grinding, the traverse cylinder 41 is operated in the opposite direction to move the truing tool T in the positive direction of the V-axis to the origin position, thereby completing the truing. Thereafter, in step 130, the grindstone head is advanced by ΔU+C in the normal direction. As a result, the position of the ground surface Ga viewed from the workpiece W side is the ground surface before truing.
It will be the same position as Ga.

Next, in steps 132 to 144, the contact S is brought into contact with the ground surface immediately after truing, and the ground surface is
This is the process of measuring and storing the positions of Ga and Gb with the origin of the contact as a reference. Step 134 is similar to steps 100 and 102 described above. Also, step 136
Then, the detected movement amount is stored in the MO as the position of the grinding surface immediately after the previous truing.
After returning the contact to the origin in step 138,
Shift the contact by K in the -V direction and step
140, measure the feed amount in the same way for the other grinding surface Gb. Its value is set to NO in step 142.
is memorized. Next, in step 144, the contact S is returned to the origin, and the process ends. Through the above-described processing, the grinding wheel can correct errors caused by displacement in the axial direction and accurately true the grinding surfaces Ga and Gb.

When the trueing of the ground surfaces Ga and Gb is completed through the above processing, in step 146, the displacement amount △ calculated in step 120 is determined.
Z is added to the correction value register CVR to update the correction movement amount CV in the workpiece table 11. This correction value register VCR is installed with a new grinding wheel G,
It is reset to zero when the positional relationship between the top P of the grinding wheel G and the top of the template 33 is matched, and thereafter, the displacement ΔZ is cumulatively added every time truing is performed. Therefore, the correction value register
The value of VCR is determined in the direction parallel to the axis of the workpiece W on the path R through which the top P of the grinding wheel G passes, with the top of the template 33 whose position does not change due to thermal expansion and contraction of the grinding wheel G as a reference. It represents the amount of positional deviation.

On the other hand, when a machining command is given to the computer 50, the computer 50 performs the table positioning process shown in FIG. 9, and then executes a machining program (not shown).

In step 200, the end face sizing device 19 is advanced so that the feeler of the end face sizing device 19 can engage with the reference surface Ws of the workpiece W as shown in FIG. Pulse distribution is performed to position the workpiece table 11 at a position where the output of the end face sizing device 19 is zero. As a result, the plane passing through the reference end surface Ws of the workpiece W is
The path taken by the top of the grinding wheel G when there is no thermal displacement
It is located at the intersection point CPO of the main axis OS with RO.

Furthermore, in step 204, the amount of deviation L between the reference end surface Ws and the shoulder end surface Wb in the direction parallel to the workpiece axis direction, and the finished diameter D of the cylindrical portion Wa are determined.
Based on this, the table shift amount S is calculated by formula (4) as S=L-(D/2tanθ)...(4), and in step 206,
From this shift amount S, the table correction amount CV calculated at the time of truing is subtracted, and the table movement amount Zl is calculated.
Calculate.

Then, in step 208, pulse distribution is performed on the Z axis, and the workpiece W is moved to the left in FIG. 12 by a movement amount Zl.

As a result, the workpiece W is positioned at a position where R of the grinding wheel G passes through the intersection of the shoulder end surface Wa and the cylindrical portion Wb at the time of completion of grinding.

In this way, the shift amount S of the workpiece table 11 determined by the shape of the workpiece W is determined by the top P of the grinding wheel G.
Since the movement amount Zl of the workpiece table 11 is calculated by correcting it by CV proportional to the thermal displacement amount,
After such a positioning operation, regardless of the thermal displacement of the top P of the grinding wheel G, the path R taken by the top P is
It passes through the intersection of the shoulder end face Wa and the cylindrical part Wb during finishing.

Therefore, by executing the machining program that follows, the grinding surface Ga is engaged with the cylindrical part Wa, and the cylindrical part Wa is ground to the finished dimension based on a signal from a sizing device (not shown). Shoulder end face
Wb will be ground to the specified finish dimensions with high precision.

<Effects of the Invention> As described above, in the present invention, the displacement of the top of the grinding wheel is detected, the movement of the truing tool is corrected based on this displacement, and the relative position between the workpiece and the grinding wheel is corrected. The path taken by the top of the grinding wheel is corrected so that it passes through the theoretical passing point set on the workpiece, so even if the top of the grinding wheel changes due to thermal expansion and contraction of the grinding wheel shaft, the path taken by the top of the grinding wheel can be minimized. This has the advantage that the grinding surface can be trued in a short period of time, and the machining accuracy of the shoulder end face of the workpiece is not deteriorated, and the machining accuracy of the workpiece can be improved without increasing the wear amount of the grinding wheel. be.

[Brief explanation of drawings]

FIG. 1 is a diagram showing truing in which the position of the top P of the grinding wheel G does not change, FIG. 2 is a diagram showing truing in which the consumption amount of the grinding wheel G is reduced, and FIG.
12 show embodiments of the present invention, FIG. 3 is a schematic plan view of a grinding machine, FIG. 4 is an enlarged view of the truing device 30 in FIG. 3, and FIG. 5 is an enlarged view of the truing device 30 in FIG. V-V line cross-sectional view, Figure 6 is the 5th
7 is a block diagram showing the control circuit, FIGS. 8 and 9 are flowcharts showing the operation of the computer 50 in FIG. 7, and FIGS. 10a and 10b are surface positions. A diagram showing the positional relationship between the contact S and the grinding wheel G during the detection operation, FIG. 11 is a diagram showing the relationship between the displacement of the grinding surfaces Ga and Gb and the displacement of the top P, and FIG. 12 is the positioning operation of the workpiece W. It is an explanatory diagram for explaining. 11... Workpiece table, 12... Headstock, 1
3... Tailstock, 17... Servo motor, 20...
Grinding wheel head, 23... Servo motor, 30... Truing device, 40... Surface position detection device, 50...
...Computer, 53...Contact detection circuit, G...
Grinding wheel, P...Top, R...Route, S...Contact, T...Truing wheel.

Claims (1)

[Claims] 1. The workpiece is moved in a direction parallel to the spindle axis to position the workpiece in the axial direction, and then an angular grinding wheel having a pair of grinding surfaces perpendicular to each other is moved to intersect with the spindle axis. In this angular grinding machine, the truing tool is installed on a grinding wheel head that holds the angular grinding wheel, and the truing tool is connected to the angular grinding wheel. a moving device that moves in the axial direction of the wheel and a direction perpendicular to the axis, and a truing tool control means that drives the moving device based on shape data corresponding to a pair of mutually orthogonal grinding surfaces of the angular grinding wheel; , the positions of the pair of grinding surfaces in the cutting direction of the grinding wheel are respectively immediately before truing,
a grinding surface detection means for detecting immediately after, a position storage means for storing each position of the grinding surface detected by the grinding surface detection means in the cutting direction of the grinding wheel, and a position storage means for storing each position of the grinding surface detected by the grinding surface detection means immediately before truing, which is stored in the storage means immediately before truing. a first calculation means for calculating a displacement in a direction parallel to the axis of the top grinding wheel where the pair of grinding surfaces intersect from the detected position and the position detected immediately after the previous truing; and a truing stored in the storage means. a second calculation means for calculating a displacement in a direction parallel to the workpiece axis at the top where the pair of grinding surfaces intersect from the position detected immediately before and the position detected immediately after the previous truing; and the first calculation means shape data correction means for correcting the shape data in a direction parallel to the grinding wheel axis based on the displacement of the top part in a direction parallel to the grinding wheel axis calculated by the second calculation means; The position of the workpiece in the direction of the spindle axis is corrected based on the displacement in the direction parallel to the workpiece axis so that the path of the grinding wheel passing through the top of the grinding wheel passes through a theoretical passing point set on the workpiece. A position correction device for an angular grinding machine, characterized in that a position correction means is provided for adjusting the position. 2. The position correction means holds the workpiece,
a workpiece table that is movable in a direction parallel to the workpiece axis; and a table position that corrects the position of the workpiece table based on the displacement of the top part in the direction parallel to the workpiece axis calculated by a second calculation means. Claim 1, characterized in that it consists of a correction means.
A position correction device for an anguilla grinding machine as described in 2.