JPH054167A - Grinding apparatus - Google Patents

Abstract

PURPOSE:To zero a defective straightness on the traverse grinding end of a work. CONSTITUTION:The grinding apparatus for traverse grinding of a work W is provided with a control means 120 adapted to control at least one of a drive means 100 for a work table 14, a main shaft supporter 16, a wheel spindle stock 12, and a drive means 110, thereby varying at least one of the table feed speed, work rotation speed, grinding wheel peripheral speed, and cut depth so as to cause the grinding resistance to become constant through a change in a grinding width of grinding wheel participating in the work grinding operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding device, and more particularly to a grinding device for traverse grinding a workpiece in one pass using a grindstone having a thin width.

[0002]

2. Description of the Related Art Conventionally, this type of grinding apparatus generally supports both ends of a work piece by a headstock and a tailstock on a worktable table which generally traverses, and the worktable is held on the worktable. By traversing in a direction parallel to the rotation axis, the outer peripheral surface of the workpiece is cylindrically ground in one pass.

[0003]

However, in such a conventional grinding machine, when one-pass traverse grinding is carried out with a grindstone having a thin width, as shown in FIG. There is a problem that the straightness of the work is deteriorated because it is ground more than the cylindrical surface. The reason why the straightness deteriorates in this way is that the grinding width B of the grindstone 2 which was involved in the grinding of the work piece 1 is applied to the work end in the 1-pass traverse grinding process of the work piece as shown in FIG. 8A. Then, as shown in FIG. 8b, the grinding resistance changes in the decreasing direction, and the grinding resistance of the grindstone also changes in the decreasing direction. For example, if the positional relationship between the grindstone 2 and the end of the workpiece 1 is as shown in FIG. 8b,
The grinding wheel grinding width B involved in grinding is B / 2, and the grinding resistance is also halved. As a result, the grinding efficiency per one rotation of the grindstone is increased, resulting in excessive cutting. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a grinding device capable of preventing a straightness defect at a traverse grinding end of a workpiece.

[0004]

The present invention will be described with reference to FIG. 1 which is a diagram corresponding to the claims. The present invention is based on a headstock 1 having a work drive motor 16a for rotationally driving a work.
6, a grindstone 12 having a grindstone driving motor 12a for rotating the grindstone, a headstock 16 and a grindstone 12 in a direction in which the workpiece W and the grindstone 12 approach and separate from each other and in a rotation axis direction of the workpiece. Drive means 100, 1 for relative movement
And the headstock 16 and the grindstone base 12 are moved relative to each other, and are applied to a grinding apparatus for traverse grinding the workpiece W.

The above-mentioned object is to increase the traverse speed, decrease the depth of cut, and decrease the rotational speed of the workpiece in accordance with the reduction of the grinding wheel grinding width involved in the workpiece grinding at the end of the workpiece. This can be achieved by providing control means 120 for controlling at least one of the drive means 100, 110, the workpiece drive motor 16a, and the grindstone drive motor 12a in the direction of decreasing the grinding wheel peripheral speed.

[0006]

With the above construction, when the grinding wheel 11 is moved relative to the work W in the direction of the rotation axis of the work W, the grinding wheel grinding width involved in the work grinding at the end of the work is reduced. At this time, the control means 120 drives the driving means 100, 110, the workpiece drive in the direction of increasing the traverse speed, the direction of decreasing the cutting depth, the direction of decreasing the workpiece rotation speed, and the direction of decreasing the grinding wheel peripheral speed. Motor 16
a, at least one of the grindstone drive motors 12a is controlled. As a result, over-cutting at the end of the workpiece is eliminated, and the straightness defect of the workpiece W can be eliminated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is an overall configuration diagram of the grinding apparatus according to the present invention. In FIG. 2, 10 is a grinder and 20 is a numerical controller. The grinder 10 is provided with a grindstone base 12 for rotatably supporting a grindstone wheel 11 having a thin width sufficiently smaller than the length L of the workpiece W, and a worktable 14 on which the workpiece W is mounted.
2 is moved on the head 19 by the servo motor 13 in the X-axis direction, and the workpiece table 14 is moved on the head 19 by the servo motor 15 in the Z-axis direction. On the work table 14, a headstock 16 and a tailstock 17 are installed opposite to each other with their axes aligned, and both ends of the work W are held by the headstock 16 and the tailstock 17. Reference numeral 18 is a grindstone correction tool attached to the headstock 16. Reference numeral 12a is a grinding wheel drive motor that rotationally drives the grinding wheel 11, and 16a is a workpiece drive motor that rotationally drives the workpiece W.

The numerical controller 20 includes a central processing unit (hereinafter referred to as CPU) 201 for controlling and managing the whole, and a CP.
A storage device 202 connected to the U201, an X-axis pulse distribution circuit 203 that outputs a number of pulse signals according to a command value from the CPU 201, and a Z-axis pulse distribution circuit 20.
4 and an interface 205. The X-axis pulse distribution circuit 203 is connected to the grindstone head feed servo motor 13 via the drive circuit 30, and the Z-axis pulse distribution circuit 204 is connected to the table feed servo motor 15 via the drive circuit 31. It is supported. Further, the interface 205 is connected to an input device 32 for inputting and setting a machining program, correction data and the like into the storage device 202 and for inputting signals such as control commands.

The storage device 202 changes a grinding program such as a machining program for grinding the workpiece W and table feed speed (traverse speed) so that the grinding resistance is constant even at the traverse grinding end of the workpiece W. The correction data and the like are stored. As the correction data for changing the grinding conditions, for example, as shown in FIG. 3, the number K of steps corresponding to the number N of corrections set according to the grinding wheel grinding width B,
The table is constructed with a table feed speed correction command value f (K) previously obtained corresponding to this K.
Note that f (K) is a function that depends on the grinding position of the grindstone with respect to the workpiece and that the tangential grinding resistance becomes constant.

Next, the operation of this embodiment configured as described above will be described with reference to FIGS. When the grinding device is activated, the program shown in FIG. 4 is executed according to the grinding program. First, in step S1, the grinding wheel grinding width B
And the unit traverse amount ΔB, the number of corrections N at the end portion of the workpiece W corresponding to the grinding width B is set. In the next step S2, the step number K corresponding to the set number N is set to K =
Set to 0. In the next step S3, the grindstone head 12 is moved forward in the workpiece direction by the forward movement command value Xi = A1 read from the storage device 202 into the CPU 201. That is, the command value Xi = A1 is decoded by the CPU 201, and the decoded command data is added to the pulse distribution circuit 203, so that the pulse distribution circuit 203 outputs a number of pulses corresponding to the command data, and the pulses are output to the drive circuit 30. In addition to the above, the servomotor 13 is driven to move the grindstone base 12 forward by the number of command pulses toward the workpiece W, and the grindstone 11 is moved to the position shown in FIG.
The workpiece W is moved to the grinding start position indicated by the alternate long and short dash line. At this time, the grinding wheel 11 and the workpiece W are rotating at a preset speed.

In the next step S4, the table feed amount command value Z read from the storage device 202 to the CPU 201.
i =-(LB), the table feed speed command value F = A2 is moved to the left. That is, the table feed amount command value Z
The number of pulses corresponding to i =-(LB) is the speed command value F = A
By applying a pulse from the pulse distribution circuit 204 to the drive circuit 31 at a pulse interval corresponding to 2, the servo motor 15 is driven to move the work table 14 to the left.
Thus, the workpiece W is cylindrically ground over the entire grinding width B of the grinding wheel 11. At this time, as shown in FIG. 6, the feed speed F of the work table 12 is kept constant until the LB traverse position is reached. In the next step S5, it is determined whether or not the traverse position of the work table 14 is Zi =-(LB). However, L represents the length of the workpiece W.
Here, when it is determined that Zi =-(LB) is not satisfied, the process returns to step S4, and the traverse position of the workpiece table 14 becomes a value obtained by subtracting the grindstone grinding width B from the length L of the workpiece W. The table 12 is moved to the left at speed A2. On the other hand, the position of the work table 14 is Zi =-
When it is determined that (LB) has occurred, that is, the grinding wheel 1
When 1 reaches the stage where the end of the workpiece W begins to be contacted as shown by the chain double-dashed line in FIG. The address of the correction data table stored in is specified, and the table feed speed correction command value f (K) stored at address K + 1 is read.
Here, the correction command value read first from the correction data table is f (K) = 1.1, as is apparent from FIG.
Is. Also, when K = 0, it becomes 1.0.

In the next step S7, the correction command value read from the correction data table according to K = K + 1 is multiplied by the table speed A2 when the entire grinding width B is ground F = f (K) * The work table 14 is moved leftward by the unit traverse amount Δ at a speed of A2. That is, by increasing the feed speed of the workpiece table 12, the grinding resistance is made the same as when grinding the entire grinding width B.

In the next step S8, it is determined whether the step count K has reached the correction count N. Here, when it is determined that N = K is not satisfied, the process returns to step S6, and the processes of steps S6 to S8 are executed until N = K.
At this time, as the step count K increases, the correction data of f (K) corresponding to the step count K is sequentially read from the table of the storage device 202, and F = f (K).
* Workpiece table 14 with the speed calculated by A2
In increments of ΔB to the left until the grinding wheel 11 passes the end of the workpiece W. As a result, the feed speed F of the work table 14 in the leftward direction at the end of the work W rises in a quadratic function as shown in FIG. 6, whereby the grinding wheel resistance at the end of the work is kept constant. As described above, the straightness of the workpiece W can be obtained by eliminating the excessive cutting.

If it is determined in step S8 that N = K, the process proceeds to step S9, in which the grindstone 12 is retracted, and then the work table 14 is moved to the right to return to the grinding start position. Return to the cylindrical grinding process. As described above, in this embodiment, even if the grindstone grinding width involved in the traverse grinding of the work changes at the end of the work, the feed speed of the work table is changed so that the grinding resistance becomes constant. Since the structure is adopted, it is possible to obtain the straightness of the work by eliminating the overcutting at the end of the work which has been conventionally generated.

In the above embodiment, by changing the feed rate of the work table, the grinding resistance at the work end side (traverse end side) is assumed when the entire grindstone grinding width is involved in grinding. The control method for making the grinding resistance the same as the above has been described, but the present invention is not limited to this. For example, the grinding resistance is changed by changing the grinding condition by at least one of the rotation speed of the workpiece including the table feed speed (lowered at the workpiece end side) and the grinding wheel peripheral speed (lowered at the workpiece end side). It can also be controlled. Further, if the cutting depth is reduced as the grindstone grinding width at the end of the workpiece is reduced, excessive cutting at the end of the workpiece can be eliminated.
Furthermore, instead of moving the workpiece table in the traverse direction, the grindstone head may be moved in the traverse direction.

In the above embodiment, the servo motor 13 is the driving means 110, and the servo motor 15 is the driving means 100.
The CPU 201 and the storage device 201 make the control means 120
Respectively.

[0017]

As described above, according to the present invention,
Even if the grinding width of the grindstone involved in the traverse grinding of the work at the end of the work decreases, the grindstone decreases in the direction in which the work rotation speed decreases, the table feed speed increases, and the cutting depth decreases. Since the control method is such that at least one grinding condition is changed in the direction in which the peripheral speed decreases, there is an effect that over-cutting at the traverse end of the workpiece is eliminated and straightness can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of a grinding device according to the present invention.

FIG. 2 is an overall configuration diagram showing an embodiment of a grinding apparatus according to the present invention.

FIG. 3 is an explanatory diagram showing a table construction example of correction data in the present embodiment.

FIG. 4 is a flowchart showing an operation procedure of grinding in this embodiment.

FIG. 5 is an explanatory diagram showing a positional relationship between a workpiece and a grindstone in the present embodiment.

FIG. 6 is an explanatory characteristic diagram showing the relationship between the table feed speed and the trace position in this embodiment.

FIG. 7 is an explanatory diagram showing a conventional grinding state of a workpiece.

FIG. 8A is an explanatory diagram showing a state in which the entire grinding width of the grindstone is involved in grinding. FIG. 7B is an explanatory diagram showing a state when the grindstone is located at the end of the workpiece.

[Explanation of symbols]

 10 Grinding machine 11 Grinding wheel 12 Grinding wheel base 13 Servo motor 14 Work table 15 Servo motor 16 Spindle base 17 Tailstock 20 Numerical control device 201 CPU 202 Storage device 203,204 Pulse distribution circuit 205 Interface 30, 31 Drive circuit 32 Input Device 100 Driving means 110 Driving means 120 Control means

Claims (1)

Claim: What is claimed is: 1. A headstock having a work driving motor for rotating a work, a grinding head having a grinding wheel drive motor for rotating a grinding wheel, a work and a grinding wheel. Have a drive means for relatively moving the headstock and the grindstone head in a direction in which they approach and separate from each other and in a rotation axis direction of the workpiece, and by performing relative movement of the headstock and the grindstone head, grinding for traverse grinding the workpiece In the device, the traverse speed is increased, the depth of cut is decreased, the rotational speed of the work is decreased, and the peripheral speed of the grindstone is decreased in accordance with the decrease in the grinding wheel grinding width that is involved in the grinding of the workpiece at the end of the workpiece. A grinding machine comprising a control means for controlling at least one of the drive means, the workpiece drive motor, and the grindstone drive motor in a lowering direction.