JP2973196B2 - Grinding method for non-round workpieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for grinding a non-circular workpiece by preparing data for spindle rotation control in the grinding of a non-circular workpiece.

[0002]

2. Description of the Related Art A grinding machine for grinding a cam, which is a non-round workpiece, is used for controlling a spindle rotation over one rotation range of a cam based on profile data representing the non-round shape of a cam as a final product. Data is created, and the spindle controller controls the rotation of the spindle based on the data.

The spindle rotation control data specifies the rotation speed of the spindle at a rotation angle position at an appropriate angular interval of the cam so that the grinding resistance during grinding is always kept constant.

[0004] This data is generally created artificially based on the experience and feeling of the operator, such as by repeating test processing, but this takes too much time. In order to cope with this, in Japanese Unexamined Patent Publication No. 9-251311, data for spindle rotation control is mechanically created by an electronic computer.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-open No. Hei 9-2
In the technique of No. 51311, the main shaft rotation speed at the rotation position at an appropriate angular interval of the cam is calculated from the radius of curvature of a specific point on the cam peripheral surface related to the rotation position.

Although the processing speed is dramatically improved by this method as compared with the case of artificially, the fact that the calculation of the radius of curvature is a relatively cumbersome calculation including the first derivative and the second derivative is a problem in the data creation process. In addition to hindering further improvement, it also causes data accuracy to be impaired, which in turn reduces grinding efficiency. An object of the present invention is to solve such a problem.

[0007]

In order to achieve the above object, in the method of preparing spindle rotation control data according to the present invention, the spindle rotation speed for equalizing the grinding resistance or an index for representing this speed is used. The non-circular workpiece corresponding to the main spindle rotation angle at an appropriate angular interval is mechanically calculated using a calculation formula that does not use the curvature radius of the workpiece as a variable. According to this, it is not necessary to calculate the radius of curvature, so that the processing of the primary differentiation and the secondary differentiation becomes unnecessary.

[0008] The above calculation formulas include: a base circle radius, a reference rotation angular velocity, a rotation radius, a rotation angle, and a contact angle of a non-circular workpiece;
The peripheral speed and contact angle of the grindstone for grinding the workpiece, and the moving speed of the cutting point are set as dimensional numbers to be specified. More specifically, the dimensional number and the trigonometric function value related to the contact angle are added, multiplied, and divided.

In the method of grinding a non-circular workpiece, the non-circular workpiece is rotated by a spindle which is controlled and rotated, while the rotationally operated grindstone is relatively displaced in a direction intersecting with the spindle to form a non-circular workpiece. Grinding is performed, and at this time, the rotation of the spindle is controlled based on the spindle rotation control data obtained by the above formula.

[0010] More preferably, the main spindle rotation control data is displayed as a line on orthogonal coordinates in which the horizontal axis represents the rotation angle of the main spindle and the vertical axis represents a predetermined rotation ratio related to the rotation speed of the main spindle. The data is converted into data that is simplified by replacing the portion where the line becomes a curve with an appropriate number of straight lines, and the simplified data is displayed on a display device as a line or a character, and as necessary. The content of this simplified data can be corrected by manual input,
The rotation of the spindle is controlled by the simplified final data.

It is preferable that the grinding force is measured and the computer calculates the maximum reference rotation angular velocity as large as possible so that the grinding resistance does not exceed a predetermined value, and the main shaft rotation control data is created from the reference angular velocity. According to this, the processing efficiency is largely maintained as long as the quality of the workpiece does not deteriorate.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The spindle rotation control data is created as follows.

That is, the computer stores profile data representing a non-perfect circle of the cam 1 as a final product. This profile data represents, for example, the radius of rotation r of the cam 1 at the position of the rotation angle C for each unit angle interval.

Then, a required numerical value relating to the cam 1 as a final product is specified and input to an electronic computer. The required numerical values include a base circle radius r ₀ and a reference rotation angular velocity ω.
It is ₀ . Here, the base circle radius r ₀ is a radius of the base circle portion 1a having a constant radius of curvature, and refers to a dimension from the rotation center o to the outer periphery of the base circle portion 1a, and the reference rotation angular velocity ω ₀
Is an angular velocity used as a reference for calculation, and is an angular velocity around the rotation center o of the cam 1 when grinding the base circle portion 1a.

At this time, the basic circle radius r ₀ is specific to the cam 1 as the final product, and can be immediately known from the above profile data. The reference rotational angular velocity ω ₀ may be an arbitrary specific value, and may be appropriately determined based on past experience or the like.

Further, a radius R and a rotational peripheral speed V ₀ of the grindstone 2 for cutting a workpiece are specified and input. The radius R and the rotational peripheral speed V ₀ are determined by specifying a grinding device for grinding the cam 1.

Next, the cam 1 fixed to the main shaft of the grinding device
When the cam 1 is rotated in the same manner as the main shaft, the rotation radius r and the rotation angle C of the cam corresponding to the point (grinding point) P at which the cam 1 comes into contact with the grindstone 2 relatively displaced in a direction perpendicular to the main shaft.
And the contact angle β, the contact angle δ of the grinding wheel 2, and the moving speed v _P of the grinding point P are specified for the rotation angle C of the cam at each unit angular interval.

Here, the radius of rotation r of the cam 1 corresponding to the grinding point P means a linear dimension from the center of rotation o to the grinding point P, and the rotation angle C means that the cam 1 contacts the grinding wheel 2 at the cutting point P. The center of rotation o and the center of rotation o of the whetstone 2
1, the angle formed by the straight line s1 passing through the center point of the length of the base circle portion 1a and the center of rotation o with respect to the straight line s2 passing through the cam 1 and the grinding wheel 2 at the cutting point P. The grinding point P and the rotation center o with respect to the straight line s1
And the angle formed by a straight line s3 passing through.

The contact angle δ of the grindstone 2 is
It refers to the angle formed by a straight line passing through the grinding point P and the rotation center o1. Also the movement speed v _P of the grinding point P, since cam 1 is non-round, again grinding point P of rotating the cam 1 to the main shaft and the homologues are the tangential s4 direction of the grinding wheel 2 the peripheral surface of the point P It moves at a specific speed, and refers to the moving speed at this time.

In these specifications, the computer is caused to execute necessary calculations. At this time, since the reference rotation angular velocity ω ₀ , the profile data representing the non-circular shape of the cam 1 and the radius R of the grinding wheel 2 have already been specified, the rotation radius r and the contact angle β of the cam 2 described above, The angle δ and the moving speed of the grinding point P are easily calculated for each rotation angle C. However, this calculated value is related to the previously specified reference rotational angular velocity ω ₀ .

Then, the rotational speed (angular velocity) ωt of the main shaft at each rotational angle C position at an appropriate angular interval of the cam 1 is calculated by a predetermined formula so that the grinding resistance during grinding is always constant. Let it. The calculation formula (Equation 1) at this time is as follows.

[0022]

(Equation 1)

Here, ωt is the rotational angular velocity of the cam 1 (main shaft), and v _p (= Equation 2) is determined when the rotational angular velocity ωt of the cam 1 is specified by the moving velocity of the grinding point P. Number 2
In the equation, T represents time.

[0024]

(Equation 2)

This calculation formula is for a cam 1 which is a non-circular workpiece.
The base circle radius r ₀ , the reference rotation angular velocity ω ₀ , the rotation radius r,
The contact angle β and the rotation angle C, the peripheral speed V ₀ and the contact angle δ of the grinding wheel 2 for cutting the cam 1, and the moving speed v _p of the grinding point P are dimensional numbers to be specified. The number of dimensions and the trigonometric function values related to the contact angles β and δ are added, multiplied and divided.

Therefore, the radius of curvature of the cam 1 which requires the first and second derivative calculations is not included.

[0027] Since the right-hand side of the equation are not independent with respect to the rotational angular velocity ω _t, the rotational angular velocity ω _t to satisfy the equation
In order to specify, the rotation angular velocity ω _t is sequentially changed, and the calculation is repeatedly performed, so that the error between the values on the left and right sides is within an allowable range.

Thus, the rotation angle C of the cam 1 within one rotation range of the cam 1 (this is the same as the rotation angle of the main shaft)
Spindle rotation control data for specifying a relationship with the rotation angular velocity ω _t of the cam 1 at the position of the rotation angle C (this is the same as the rotation angular velocity of the spindle) is obtained, and this data is stored in a computer.

When machining is performed based on this data, a driving means for relatively displacing the grindstone 2 with respect to the main shaft is caused to calculate an acceleration to be generated. If the acceleration does not exceed an allowable range, this data is used as temporary fixed data. None, if it exceeds one, the reference rotation angular velocity ω ₀ is set again to a small value, and again, the above-described calculation is repeated to create new spindle rotation control data, and the spindle rotation with respect to the maximum allowable reference rotation angular velocity ω ₀ is repeated. The control data is specified, and the data is replaced with temporary spindle rotation control data and stored as temporary fixed data.

Next, the cam 1 to be ground is fixed to the main shaft. At this time, the cam 1 is brought into a state in which the position where the rotation angle of the cam 1 is 0 degrees and the position where the rotation angle of the main shaft is 0 degrees are matched. Then, grinding is performed by specifying the cutting amount of the grindstone 2 to a required size. At this time, the rotation of the spindle is controlled based on the temporarily determined spindle rotation control data.

The grinding wheel 2 is controlled so as to be relatively displaced in a direction perpendicular to the main axis by the same control data as the conventional one, the description of which is omitted, whereby the cam 1 is moved to its final non-roundness. The peripheral surface is ground under a constant grinding force according to the represented profile data.

During processing, the actual grinding force is measured by a measuring device incorporated in the grinding device, and when this measured value does not exceed an allowable range, this is regarded as final confirmed data,
Meanwhile repeated to create a new spindle rotation control data by calculation again, the newly set further smaller, the standard rotational angular velocity omega ₀ of the cam 1 when crossing, to the maximum reference rotation angular velocity omega ₀ allowed Identify the spindle rotation control data, replace it with the previous spindle rotation control data as final fixed data, and store it in the computer.

Thereafter, full-scale cutting of the cam 1 as a workpiece is performed based on the final spindle rotation control data obtained by such processing.

Further, in the present embodiment, a display device for displaying the spindle rotation control data as temporary or final fixed data obtained as described above is provided, and this display device is provided with this display device. The contents can be displayed as a curve on rectangular coordinates as shown in FIG.

In this case, the horizontal axis of the coordinate is the rotation angle C of the main shaft.
The vertical axis represents the rotation ratio (= ω _t / ω ₀ × 100) obtained by dividing the rotation angular speed ω _{t of the} main shaft by the reference rotation angular speed ω _0.
%). When data is displayed as a line on the coordinates in this way, if there is an error in the calculation,
The operator can immediately judge it visually.

The lines representing the spindle rotation control data as described above are simplified as necessary so that the results can be displayed on a display device.

That is, the approximate calculation by the computer is simplified, as shown in FIG. 3, in which the curved line portion of the line representing the spindle rotation control data on the coordinates is approximately replaced by an appropriate number of straight lines. The main shaft rotation control data is converted so as to be represented by a broken line, and the simplified line is displayed on a display device or displayed by characters. As the display by characters, for example, the rotation angle range of the main shaft as shown in FIG. 4 and the rotation ratio (= ω _t) within each range are shown.
/ Ω ₀ × 100%).

When the operator recognizes that the content of the simplified data is satisfactory, the rotation of the main shaft may be controlled based on this data.

On the other hand, if the operator recognizes that the user is unsatisfied, he or she can manually input the correction information by manually inputting the displayed rotation angle range and rotation ratio from an input device such as a keyboard as necessary. Thus, the contents of the simplified data can be appropriately modified.

Then, the rotation of the main shaft is controlled based on the corrected data. This allows
Processing errors due to inadvertent factors can be easily and quickly eliminated.

[0041]

According to the present invention described above, it is not necessary to calculate the first derivative and second derivative when calculating the radius of curvature of the cam, so that the information processing is simplified and the speed is further accelerated. Thus, high-quality grinding can be efficiently performed under a constant grinding force. In particular, when grinding with a constant resistance cannot be performed due to a factor that was not planned when creating the spindle rotation control data, this can be quickly corrected to perform the required grinding.

According to the third aspect, the variables can be easily specified, the accuracy is improved, and the calculation process is facilitated because the number of dimensional numbers to be specified is small.

According to the fourth aspect of the present invention, the calculation formula is simple and does not require complicated processing such as differentiation, and the spindle rotation control data can be obtained quickly.

According to the fifth aspect, high-quality grinding can be efficiently performed under a constant grinding force without calculating the first derivative or the second derivative when calculating the radius of curvature of the cam. It will be.

According to the sixth aspect of the present invention, the cutting force exceeds the allowable range due to a factor not intended in the grinding based on the spindle rotation control data obtained by the mechanical operation without measuring the actual grinding force. It is possible, but at this time it can be quickly and mechanically corrected.

[0046]

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a cam is ground by a grindstone in a grinding device.

FIG. 2 is a diagram showing spindle rotation control data as final fixed data on coordinates.

FIG. 3 is a diagram in which main spindle rotation control data as final fixed data is simplified and displayed on coordinates.

FIG. 4 is a diagram showing a state in which main shaft rotation control data as final fixed data is displayed in characters.

[Explanation of symbols]

1 cam (workpiece) r ₀ basic circle radius ω ₀ reference rotation angular velocity β cam contact angle δ grinding wheel contact angle C cam rotation angle (spindle rotation angle) P grinding point V ₀ grinding wheel peripheral velocity

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-305434 (JP, A) JP-A-9-251310 (JP, A) JP-A-9-97103 (JP, A)

Claims (6)

(57) [Claims] 1. A rotational speed of a spindle for equalizing a grinding force or an index for representing the speed, which corresponds to a rotational angle of a spindle at an appropriate angular interval of a non-circular workpiece. Equations that do not use the radius of curvature as a variable, that is, the base circle radius of a non-circular workpiece, the reference rotation angular velocity, the rotation radius,
There is no spindle rotation control data calculated as a dimensional number to specify the rotation angle and contact angle, the peripheral speed and contact angle of the grinding wheel for grinding this workpiece, and the moving speed of the grinding point. In the case where the spindle rotation control data is represented by a line representing a rotation angle of the spindle on one axis and a rotation ratio related to the rotation speed of the spindle on orthogonal coordinates represented on the other axis, the line becomes a curve. Is converted to simplified data so as to be replaced with an appropriate number of straight lines, and the simplified data is displayed as a line or a character on a display device, and the rotation of the spindle is simplified. A non-round work grinding method characterized by control with final data. 2. The rotational speed of the spindle for equalizing the grinding force or an index for representing this speed, which corresponds to the rotational angle of the spindle at an appropriate angular interval of the non-circular workpiece. Equations that do not use the radius of curvature as a variable, that is, the base circle radius of a non-circular workpiece, the reference rotation angular velocity, the rotation radius,
There is no spindle rotation control data calculated as a dimensional number to specify the rotation angle and contact angle, the peripheral speed and contact angle of the grinding wheel for grinding this workpiece, and the moving speed of the grinding point. In the case where the spindle rotation control data is represented by a line representing a rotation angle of the spindle on one axis and a rotation ratio related to the rotation speed of the spindle on orthogonal coordinates represented on the other axis, the line becomes a curve. Is converted to simplified data so as to be replaced with an appropriate number of straight lines, and the simplified data is displayed as a line or a character on a display device. A non-circular workpiece grinding method, characterized in that the contents of the data can be corrected by manual input, and the rotation of the spindle is controlled by the simplified final data. 3. The calculation formula is a base circle radius of a non-circular workpiece,
Reference rotation angular velocity, rotation radius, rotation angle and contact angle, and peripheral speed and contact angle of the grinding wheel for grinding this workpiece,
3. The method for grinding a non-circular workpiece according to claim 1, wherein the moving speed of the grinding point is a dimensional number to be specified. 4. The formula for calculating the radius of a base circle of a non-circular workpiece,
Reference rotation angular speed, rotation radius, rotation speed and contact angle, and the peripheral speed and contact angle of the grinding wheel for grinding this workpiece,
3. The method according to claim 1, wherein the moving speed of the grinding point is a dimension to be specified, and the dimension number and the trigonometric function value related to the contact angle are added, multiplied, and divided. Circular workpiece grinding method. 5. The method according to claim 1, wherein the non-circular workpiece is rotated by a controlled spindle, and the workpiece is ground by relatively displacing a rotationally operated grindstone in a direction intersecting the spindle. A non-circular workpiece grinding method characterized by performing control based on the spindle rotation control data according to any one of claims 1 to 4. 6. A method for measuring a grinding force, causing a computer to calculate a large reference rotation angular velocity of a workpiece such that the grinding resistance does not exceed a predetermined value, and generating spindle rotation control data from the reference angular velocity. The method for grinding a non-round workpiece according to claim 3, 4 or 5.