JPH0584648A - Grinding method - Google Patents

Abstract

PURPOSE:To traverse grind a workpiece to a degree such that improper cylindricity of a cylindrical surface final end is not problematical. CONSTITUTION:In a grinding method for traverse grinding a workpiece, rotatably supported onto a movable table, by a single pass by a rotating grinding wheel, the method comprises a process, in which the workpiece W is traverse ground at its grinding time by a cut amount with a finish margin larger than a grinding excessive amount generated in a cylindrical final end left in a side of cylindrical surfaces WR1, WR2 and a side of an end face WS1 of the workpiece W is ground so as to be finished, and a process in which the side of the cylindrical surfaces WR1, WR2 is traverse ground to finish dimension without grinding the side of the end face WS1 after ending the grinding by this former mentioned process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method applied to a grinder that traverses a workpiece in one pass by using a grindstone having a narrow width.

[0002]

2. Description of the Related Art Conventionally, in the case of traverse grinding a cylindrical multi-stage work in one pass, a notch is made in an angular type grinding wheel 1 as shown in FIG. 5, and a headstock and tailstock (not shown) are used. By traversing the work piece 2 supported by the center in the axial direction, the grinding wheel 1 is moved along the shape of the work piece as shown by the arrow for grinding.

[0003]

However, in such a conventional grinding method, when the workpiece 2 is traversed by the thin grinding wheel 1 in one pass, the cylindrical surface of the workpiece 2 is cut as shown in FIG. The end 2a is ground more than the other by Δd / 2 (usually about 0.01 mm), which causes a problem that a cylindricity defective portion occurs at the end of the workpiece.

The cause of such cylindricity is caused by the fact that the grindstone approaches the cylindrical end of the workpiece and the grinding width is reduced, the grinding resistance of the grindstone is reduced, and at the same time, the work is deformed in the radial direction. This is because the amount also decreases. That is, when the grinding conditions such as the workpiece diameter, its rotation speed, and the grindstone cutting amount are constant, the grinding resistance of the grindstone is determined by the width of the grindstone contacting the work, so that the workpiece 2 is traversed in one pass. When the grindstone 1 reaches the grinding end of the cylindrical surface as shown by the broken line in the figure, the grindstone width involved in grinding the workpiece changes in the decreasing direction, and the grinding resistance of the grindstone also changes in the decreasing direction. Since the radial force component of the grinding resistance decreases along with this, the amount of bending of the workpiece at the grinding end of the cylindrical surface becomes smaller than when the full width of the grindstone was in contact with the workpiece.
This is because many ends of the cylindrical surface are ground.

The present invention has been made in view of the above circumstances, and provides a grinding method capable of traverse grinding a workpiece to the extent that a cylindricity defect at the end of the cylindrical surface thereof does not pose a practical problem. With the goal.

[0006]

The present invention will be described with reference to FIGS. 1 and 3 showing an embodiment. In the present invention, a work W rotatably supported on a movable table 14 is provided.
It is applied to a grinding method of traverse grinding in one pass by a rotating grinding wheel 121. And the above purpose is
The traverse grinding of the workpiece W is performed at the end of the cylinder by traverse grinding with a finishing amount larger than the excess grinding amount Δd / 2 left on the cylindrical surfaces W _R1 and W _R2 , and the end surface W _S1 side of the workpiece W. Includes a first step of grinding so as to be finished, and a step of traverse-grinding the cylindrical surfaces W _R1 and W _R2 sides to a finish dimension without grinding the end surface W _S1 side after finishing the grinding in the first step. This can be achieved.

[0007]

With the above construction, the remaining amount of grinding to be traversed in the second step after being traversed in the first step is small, and the grinding resistance applied to the grindstone is greatly reduced as compared with that in the first step. Therefore, the change in the radial direction of the workpiece due to the grinding resistance also becomes small. As a result, even if the cylindrical surface is traverse ground in the second step, the cylindricity defect that occurs at the end of the cylinder can be reduced to such a degree that it does not pose a practical problem.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an overall configuration diagram of a grinding apparatus to which the method of the present invention is applied. In FIG. 1, 10 is a grinder,
Reference numeral 20 is a numerical controller for controlling the grinder 10. The grinder 10 includes a grindstone base 12 that is provided on the bed 11 so as to be movable in the X-axis direction, and a workpiece table 14 that is provided on the bed 11 so as to be movable in the Y-axis direction. The workpiece table 14 is moved in the X-axis direction by the servo motor 15 and moved in the Y-axis direction.

The grindstone base 12 is provided with a grindstone shaft 122 that supports the grindstone 121, and a drive motor 124 that rotates the grindstone 121 at a high speed via a rotation transmission mechanism 123.
On the work table 14, a headstock 16 and a tailstock 17 are provided.
Are opposed to each other with their axes aligned, and both ends of the workpiece W are center-supported by a chuck 16b provided on a spindle 16a of the headstock 16 and a tailstock 17. Further, on the bed 11, a diameter measuring device (not shown) for measuring the diameter of the workpiece W partially trial ground by the grindstone 121 is installed. The headstock 16 has a built-in drive motor (not shown) that drives the main shaft 16a.

The numerical controller 20 controls a whole and controls the central processing unit (hereinafter referred to as CPU) 21 and the workpiece W.
A processing program for grinding in two steps and a memory 22 for storing other data, and an X-axis pulse distribution for sending a pulse signal according to a command value sent from the CPU 21 by decoding the program. Circuit 2
A pulse distribution circuit 24 for 3 and Y axes is provided.

The X-axis pulse distribution circuit 23 includes a drive circuit 2
The wheel head feed servomotor 13 is connected via 5,
A table feed servomotor 15 is connected to the Y-axis pulse distribution circuit 24 via a drive circuit 26. Further, the CPU 21 is connected to an input device 27 such as an operation panel for inputting a machining program and other data and various operation commands.

Next, the operation of the present embodiment configured as described above will be described with reference to the flow chart shown in FIG. 2 and FIGS. When the grinding device is activated by a command from the input device 27, the processing shown in FIG. 2 is executed according to the machining program written in the memory 22.
First, in step S1, in order to grind the first step of the workpiece W, the grinding wheel head advance command value X = A and the table rightward command value Y = -B are stored in the memory 22 according to the machining program.
From the CPU 21 to the CPU 21, and the grindstone base 12 is moved forward by an amount corresponding to X = A and the table 14 is moved rightward by an amount corresponding to Y = -B in accordance with these command values. That is, the CPU 21 decodes the command value X = A, and the decoded command data is added to the pulse distribution circuit 23, so that the pulse distribution circuit 23 sends out a number of pulse signals corresponding to the command data.
By applying this pulse signal to the drive circuit 25, the servomotor 13 is driven to move the grindstone 12 toward the workpiece W by an amount corresponding to X = A. Further, the command value Y =-
By decoding B, the command data is applied to the pulse distribution circuit 24, and thereby the pulse signal sent from the pulse distribution circuit 24 is applied to the servomotor 15 via the drive circuit 26. -Move rightward by an amount equivalent to B.

The cutting amount added to the forward command value A is set so that the cylindrical surface W _R1 is ground while leaving a finishing allowance larger than Δd / 2 shown in FIG. In the next step S2, while the grinding wheel 121 and the workpiece W are rotated at a preset speed, the table 14 is moved leftward by an amount corresponding to Y = C to traverse the cylindrical surface W _R1 of the workpiece W. .. At this time, the command value Y = C for moving the table 14 to the left is read from the memory 22 to the CPU 21, and after the command value is decoded by the CPU 21, the decoded data is added to the pulse distribution circuit 24. The pulse distribution circuit 24 generates a number of pulse signals corresponding to Y = C, and the pulse signals are applied to the servomotor 15 through the drive circuit 26 to move the table 14 to the left. Since the grinding amount of the cylindrical portion W _R1 ends with the grinding amount of the end surface W _S1 left, it is possible to prevent a large cylindricity defect from occurring at the end of the cylindrical portion W _R1 .

When the grinding of the cylindrical portion W _R1 is completed, the process proceeds to step S3, the command value X = D is read from the memory 22, and the grinding stone head 12 is moved to X = D based on the command value X = D.
End face W of the workpiece W by advancing by an amount equivalent to
_{Grind S1} . Thereafter, in step S4, the memory 22 reads out the Y = E, an amount corresponding to the table 14 in the Y = E Based on the instruction value Y = E, further by forehand, cylindrical surface W of the workpiece W _R2 To grind.

In such a grinding process of the first step, Δd / 2
By performing a traverse grinding with a cutting amount that leaves a larger finishing allowance on the cylindrical side and grinding the end surface W _S1 side to the finished size, the workpiece before grinding shown by the solid line in FIG. W is ground into the size and shape shown by the chain double-dashed line. At this time, the cylindrical surfaces W _R1 and W to be ground in the first process
The grinding amount of _R2 is, for example, about 0.3 mm, and the end surface W
The grinding amount of _S1 is, for example, about 0.1 mm. Further, the feed speed Vs for the end surface grinding is about 1/10 of the traverse speed Vt on the cylinder side.

When the traverse grinding of the first step is completed,
In step S5, the table 14 is read by the amount corresponding to Y = N based on the command value Y = E read from the memory 22,
While moving further to the left from the grinding end point, the retreat amount X =-(A + D) of the grinding wheel base 12 is calculated, and the grinding wheel base 12 is moved backward by the amount corresponding to the calculated value and returned to the original position. Then, in step S6, the rightward travel amount Y = B- (C + E + F) of the table from the leftmost advance end to the standby position is calculated,
The table is moved to the right by an amount according to the calculated value to return to the original position, and the process proceeds to traverse grinding in the second step.

In traverse grinding of the second step, first, in step S7, the grindstone 12 is directed from the standby position toward the workpiece based on the command value X = G read from the memory 22 by an amount corresponding to X = G. To move forward. Further, based on the command value Y = -H read from the memory 22, the table 14 is moved to the right from the standby position by an amount corresponding to Y = -H. At this time, the depth of cut to be added to the forward command value G of the wheel head 12 is set to a finishing dimension including a remaining machining allowance larger than Δd / 2.

Thereafter, the process proceeds to step S8 and the memory 22
Based on the command value Y = K read from the table 14, the table 14 is moved leftward from the grinding start point by an amount corresponding to Y = K, whereby the cylindrical surface W _R1 ground in the first step is further traversed ground. The leftward movement amount Y = K on the table at this time is larger than Y = E by ΔS (about 0.01 to 0.02 mm) as shown in FIG. 4 so that the finish ground end surface W _S1 is not ground. Set to the value.

Therefore, in the next step S9,
Even if the grindstone base 12 is moved forward based on the command value X = M read out from the memory 22, the end surface W _S1 of the workpiece W is
It is not ground by 1 and moves forward by an amount corresponding to X = M. In the next step S10, the table 14 is set to Y based on the table command value Y = N read from the memory 22.
= N, the cylinder surface W _R2 ground in the first step is further traverse ground to a finished size.

A chain line shown in FIG. 4 is a processed shape at the time of traverse grinding in the second step. Cylindrical surface W at this time
Cylindrical defects also occur at the grinding ends of _R1 and W _R2 , but 1
Depth of cut on the cylindrical surface of the workpiece is 3/1 compared to the process
Since it is as small as 00 mm to 5/100 mm and the grinding resistance is small, even if the grindstone approaches the end of the cylindrical surface and the specific grinding resistance decreases, the deflection displacement of the work piece is much smaller than during the first step of grinding. .. As a result, the amount of defective cylindricity that occurs at the grinding end of the cylindrical surface does not pose a practical problem.

When the second step of grinding the cylindrical surface W _R2 is completed, the process proceeds to step S11, and the table 14 is further moved to the left by an amount corresponding to Y = P based on the command value Y = P. Then, based on the command value X =-(G + M), the grindstone base 12 is retracted from the grinding end position of the cylindrical surface W _R2 by an amount corresponding to X =-(G + M), and returned to the standby position. Then, in step S12, the table 14 is moved to the right by an amount corresponding to the command value Y = H- (K + N + P) to return to the standby position.

In FIG. 3, arrow I represents the operating sequence of the grindstone head and table in the first step, and arrow II represents the operating sequence in the second step. Then, S1 to S12 attached to the arrows I and II correspond to steps S1 to S12 in FIG. As described above, in the present embodiment, the grinding of the workpiece is divided into two steps, and in the first step, the cutting amount that leaves a finishing allowance larger than the excessive grinding amount Δd / 2 at the grinding end of the cylindrical surface on the cylindrical side. After traverse grinding and grinding the end face side so that it can be finished, in the second step, the end face side is offset by ΔS and the cylinder side is traversed to the finish dimension. The cylindricity can be processed to such an extent that it does not pose a practical problem, and the cylindricity of the workpiece can be improved as compared with the conventional method. In addition, since the end face grinding with a slow feed rate is not performed in the 2nd process, even if the grinding of the workpiece is divided into 2 steps, the machining cycle time of the workpiece should be twice or less than that of 1 time grinding. You can

In the above embodiment, the case of grinding a cylindrical multi-stage workpiece is described, but the present invention is not limited to this. For example, it can also be used for cylindrical grinding of straight workpieces. Further, the present invention is not limited to the configuration shown in the above embodiment, but can be variously modified without departing from the scope described in the claims.

[0024]

As described above, according to the present invention, traverse grinding is performed with a cutting amount left on the cylinder side for a finishing allowance larger than the excessive grinding amount generated at the cylindrical end of the workpiece, and the end face side is finished. Since it is divided into the process of grinding and the process of traverse grinding the cylinder side to the finished dimension without grinding the end face side after grinding by this process, even if the workpiece is traversed in one pass, the cylinder generated at the end of the cylinder Defects can be machined to such an extent that they are not a problem in practice, and even if traverse grinding is performed twice, the processing cycle time can be made twice or less than that of single grinding.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an example of a grinding apparatus to which a method of the present invention is applied.

FIG. 2 is a flowchart for explaining a workpiece grinding procedure in this embodiment.

FIG. 3 is an explanatory diagram showing an operation procedure of a grindstone base and a table in the present embodiment.

FIG. 4 is an explanatory diagram showing a grinding state of a workpiece in the present embodiment.

FIG. 5 is an explanatory view showing a conventional grinding method.

FIG. 6 is an explanatory diagram showing a conventional cylindricity defect at the end of a cylindrical surface.

[Explanation of symbols]

W Workpiece W _R1 , W _R2 Cylindrical surface W _S1 End surface 10 Grinding machine 12 Wheel head 13 Servo motor 14 Table 15 Servo motor 20 Numerical control device

Claims (1)

[Claims] 1. A grinding method in which a workpiece rotatably supported on a movable table is traversed in one pass by a rotating grinding wheel, and is larger than an excessive amount of grinding generated at the end of a cylinder during traverse grinding of the workpiece. The first step in which the finishing allowance is traverse-ground with the grinding amount left on the cylindrical side and the end surface side of the workpiece is finished so that the end surface side is not ground after the grinding in the first step is completed. And a step of traverse-grinding the cylindrical side to a finished size.