JP2000094291A - Machining device for incompletely round work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform positioning operation prior to machining in a short time, by providing a fast-forward means having a function capable of performing positioning of a tool stage in parallel with positioning of a main spindle when the positioning of the main spindle and the tool stage is performed preparatory to a start of machining of an incompletely round work. SOLUTION: A controller 8 has a fast-forward means. When positioning of a main spindle 25 and a grind stone stage 4 is performed preparatory to a start of machining of an incompletely round work W, the fast-forward means rotationally drives the main spindle 25 and the incompletely round work W so as to position them to prescribed rotation angle positions. In parallel with the positioning of the main spindle 25 and the incompletely round work W, the fast-forward means simultaneously moves the grind stone stage 4 to a prescribed position as adjusting an advance/retreat position of the grind stone stage 4 so as not to contact the grind stone 42 with the incompletely round work W. The fast-forward means has a function deciding the advance/retreat position of the grind stone stage 4 by composing the advance/retreat position in sync with the rotation angle position of the main spindle 25 and the advance/retreat position in sync with the rotation angle position of the incompletely round work W. The fast- forward means is stored in the controller 8 as an NC program.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an NC machine tool, and more specifically, an NC machine for performing a grinding process or a cutting process on a non-circular workpiece such as a camshaft or a crankshaft. It belongs to the technical field of numerically controlled automatic processing equipment such as grinding machines and NC lathes.

[0002]

2. Description of the Related Art A grinder is taken as an example of a conventional non-circular workpiece processing apparatus, and a description will be given of the setting of the positions of a spindle and a grindstone table before starting processing in the grinder. NC
In the grinding machine, the rotating motion of the spindle that holds and rotates the workpiece and the forward and backward motion of the grinding wheel head in the direction perpendicular to the spindle axis are controlled synchronously, and the non-circular workpiece such as a camshaft is controlled. Some have made grinding possible. In this type of grinding machine, when starting machining by attaching a non-circular workpiece to the main spindle, or grinding a grinding wheel to the next grinding location to be ground among non-circular workpieces with multiple grinding locations. When moving, it is necessary to position the grindstone as a tool table and the spindle. That is, in order to complete the preparation for machining by setting the position just before starting the grinding, it is necessary to perform a positioning operation for positioning the rotational angle position (phase) of the main spindle and the advancing / retreating position of the grinding wheel head.

In the positioning operation, it is necessary to avoid interference (contact) between the convex portion of the non-round workpiece and the grindstone as a tool. Therefore, as shown in FIGS. 6 and 7, positioning for setting the rotation angle position of the main spindle to a predetermined position is first performed, and thereafter, the grindstone head is advanced to a predetermined processing preparation completion position. Positioning is performed.

[0004]

However, in the grinding machine of the prior art, since the grindstone head is positioned after the spindle is positioned, the positioning operation before grinding takes a long time, and the cycle time is reduced. It is the cause of the increase. Therefore, an object of the present invention is to provide a non-circular workpiece processing apparatus in which a positioning operation before processing a non-circular workpiece is performed in a short time and a cycle time is reduced.

[0005]

In order to solve the above problems, the inventor has invented the following means. (First Means) A first means of the present invention is a non-circular workpiece processing apparatus according to the first aspect. Here, the non-circular workpiece is a workpiece, such as a camshaft or a crankshaft, that needs to be processed into a shape of an outer peripheral surface different from a concentric circle centered on the main shaft axis. Further, the non-circular workpiece processing device mainly refers to an NC grinding machine, but is a concept including other NC processing devices such as an NC lathe.

The present means has a control device for numerically controlling drive means such as motors provided in a non-circular workpiece processing device such as a grinding machine, and this control device is a fast-forward means as a numerical control program. have. The rapid traverse means has a function of positioning the spindle and the tool base in parallel when positioning the spindle and the tool base in preparation for starting the processing of a non-round workpiece.

In other words, in this means, before starting the machining, the tool does not come into contact with the non-circular workpiece in parallel with the operation of rotating the non-circular workpiece by the main shaft to position the workpiece at a predetermined rotational angle position. The tool table is rapidly moved to a predetermined position while adjusting the advance / retreat position of the tool table as described above. Therefore, in the present means, the positioning of the spindle and the positioning of the tool stand are performed in parallel, so that the time required for the positioning operation immediately before machining is greatly reduced, and is substantially reduced by half.

Therefore, according to the present invention, there is an effect that the positioning operation before processing the non-circular workpiece is performed in a short time, and the cycle time is shortened. As a result, there is an effect that the productivity of the non-round workpiece processing apparatus can be improved at low cost simply by changing the control program of the control apparatus. (Second Means) A second means of the present invention is a non-circular workpiece processing apparatus according to claim 2.

In this means, the control device has a function of controlling the rotation of the spindle and the advance / retreat of the tool table based on the profile data when processing a true circular workpiece. At the same time, the rapid traverse means of the control device has a function of determining the advance / retreat position of the tool table as a combination of the rapid traverse movement amount of the tool table and the movement amount of the tool table based on profile data accompanying the rapid traverse movement amount of the spindle. .

That is, the advance / retreat position of the tool table is determined by the rapid traverse means as a combination of the rapid traverse movement amount of the tool table and the movement amount of the tool table based on profile data accompanying the rapid traverse movement amount of the spindle. As a result, since the advance / retreat position of the tool stand is set with a small amount of calculation, it becomes easier to perform the positioning operation of the non-round workpiece before machining in real time.

Therefore, according to this means, in addition to the effect of the above-mentioned first means, there is an effect that it is easier to perform the positioning operation before processing the non-circular workpiece in real time. (Third Means) A third means of the present invention is a non-circular workpiece processing apparatus according to the third aspect.

In this means, when it is calculated that the retreat speed of the tool stand exceeds the limit value, the rapid traverse means appropriately reduces the rotational speed of the spindle to reduce the retreat speed of the tool stand to the limit value or less. Has the effect of setting. Conversely, in this means, when it is calculated that the retreat speed of the tool stand exceeds the limit value, the rotation speed of the spindle is appropriately adjusted so that the retreat speed of the tool stand becomes equal to or less than the limit value. Reduced.

Therefore, according to this means, in addition to the effect of the above-mentioned second means, even if it is calculated that the retreat speed of the tool table exceeds the limit value, the non-circular work piece is not stopped abnormally without stopping. There is an effect that the operation of the processing apparatus can be continued. (Fourth Means) A fourth means of the present invention is a non-circular workpiece processing apparatus according to the fourth aspect.

In this means, the fast-forward means has an operation of setting the advance speed of the tool base to the limit value when it is calculated that the advance speed of the tool base exceeds the limit value. That is, if it is determined that the forward speed of the tool table exceeds the limit value, the tool table is sent forward at the limit value of the forward speed (full speed). Therefore, according to this means, the second
In addition to the effect of the means, even when it is calculated that the advance speed of the tool table exceeds the limit value, there is an effect that the operation of the non-circular workpiece processing apparatus can be continued without abnormal stop.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the non-circular workpiece machining apparatus according to the present invention will be clearly and fully described in the following examples so that those skilled in the art can understand the present invention. Embodiment 1 (Structure of Embodiment 1) As a non-circular workpiece processing apparatus according to Embodiment 1 of the present invention, as shown in FIG. 1, a grinding machine will be described as an example. That is, the grinding machine of the present embodiment includes a headstock 24 having a spindle 25 that holds and rotates a non-round workpiece W and a grindstone 42 as a grinding tool around a grindstone axis parallel to the spindle 25. The grindstone table 4 is a tool table that is rotatably supported and driven to rotate and reciprocate relatively in a direction perpendicular to the main shaft 24, and a control device 8 that numerically controls the main shaft 24 and the grindstone table 4.

The headstock 24 and the tailstock 23 are mounted on the spindle table 2 so as to face each other, and hold the non-round work W between the spindle 25 and the tailstock 23.
4 is fixedly mounted on the spindle table 2. A reference pin 251 for matching the rotation angle position (phase) of the spindle 25 with the rotation angle position of the non-round workpiece W is provided between the end of the non-round workpiece W on the spindle 25 side and the spindle 25. Fixed.

The spindle table 2 is movable in the Z-axis direction along a guide rail 13 formed on the bed 1.
It is moved by a ball screw 14 driven to rotate by a Z-axis motor 15. Therefore, the main spindle 25 is movable in the Z-axis direction with respect to the grinding wheel head 4. Here, an axis indicating the parallel movement of the headstock 24 along the main axis is referred to as a Z-axis. Also,
The rotation axis of the main shaft 25 is referred to as a C-axis, and the C-axis is an axis indicating a rotational movement around the main shaft 25. In addition, the grindstone head 4 of the headstock 24
On the side surface, a truer 26 having a disk-shaped cutting blade driven to rotate by a motor is fixedly provided.

On the other hand, the grindstone table 4 comprises a rotating disk-shaped grindstone 42 as a tool, a grindstone shaft 43 thereof, and both 42, 43.
And a grindstone motor 46 that rotationally drives the bed 1 and is movable in the X-axis direction along a guide rail 17 formed on the bed 1. Here, the X axis is an axis orthogonal to the main shaft 25 and oriented in the direction of the main shaft 25, and indicates the parallel movement of the grinding wheel head 4. The wheel head 4 is fed in the X-axis direction by a ball screw 18 driven to rotate by an X-axis motor 19. therefore,
The wheel head 4 is movable in the X-axis direction with respect to the main shaft 25.

The headstock 24, the spindle 25, the grinding wheel head 4 and the like are all numerically controlled by the controller 8 precisely and quickly according to a predetermined control program. When positioning the spindle 25 and the grindstone head 4 in preparation for starting the processing of the non-round workpiece W, the control device 8
In parallel with the operation of rotating the non-circular workpiece W by the main shaft 25 and positioning the non-circular workpiece W at a predetermined rotation angle position, the grinding wheel 42
Has a fast-forward means for moving the grinding wheel head 4 to a predetermined position while adjusting the advancing / retreating position of the grinding wheel head 4 so as not to contact the non-round workpiece W.

The rapid traverse means determines the advance / retreat position of the grinding wheel head 4 as a combination of the advance / retreat position synchronized with the rotational angle position of the main shaft 25 and the advance / retreat position synchronized with the rotational angle position of the non-circular workpiece W. With. In addition, this fast-forward means
It is stored in the control device 8 as a numerical control program (NC program). (Operation of Embodiment 1) Since the grinding machine of this embodiment is configured as described above, the following operations and effects are exhibited. The operation of the grinding machine of the present embodiment will be described by taking as an example a case of performing cam grinding of a camshaft as a non-circular workpiece W.

As shown in FIG. 2, the NC program executed by the control device 8 includes a first line for declaring a grinding mode suitable for the non-circular workpiece W, a machining start position of the X axis and a C axis, and It includes a second line for setting the moving speed and a third line for setting the conditions for the grinding process. That is, first, when the first line N001 is executed, the code G101 is read, the control device 8 is set to the cam mode, and reads the profile data P1234 for grinding the cam of the camshaft which is a non-circular workpiece. Control device 8 is set as described above.

Next, when the second line N002 is executed, the code G00 is read, the control device 8 is set to the rapid traverse mode, the feed conditions of the X-axis and the C-axis are read, and mainly based on the feed condition. The wheel head 4 and the main shaft 25 are sent. The feed conditions are defined by a feed speed and a processing start position at which the grindstone head 4 and the spindle 25 are sent from an initial position, which is a standby position, to a processing start position, which is a preparation position for starting grinding.

The feed conditions in this case are as follows: the feed speed of the X-axis is basically 5000, the grinding wheel head 4 is fed to the feed position -30, and the rotation speed of the C-axis is 50, and the feed speed is up to 0 °. It is set to be. The feed of the X axis and the C axis in the rapid traverse mode is a main part of the present invention.
This will be described in more detail later with reference to FIGS.

Finally, when the third line N003 is executed, the code G01 is read and the cam is ground.
The grinding condition at this time is such that the initial cutting amount on the X axis is 0.
1, the cutting amount per spindle revolution is 0.1, the grinding speed per spindle revolution is 0.1, and the spindle revolution number is 20.
It is. The above operation will be described below with reference to the flowchart of FIG. 3 showing the control logic of the NC program.

First, in the processing step S100, the NC
The first line of the program is read and the code is set to G101. Then, steps S102, S104, S
After passing through steps 105, S106, and S110, the control logic proceeds to decision step S120. Judgment step S
At 120, since the code read is G101, the control logic proceeds to the processing step S121, and at the processing step S121, the control device 8 is set to the cam mode. Thereafter, the control logic goes through the remaining decision steps and returns to the start.

Next, in the processing step S100, the second line of the NC program is read, and the code is set to G00. Then, after skipping steps S102 and S104, the control logic proceeds to a determination step S105. In the judgment step S105, the read code is G
Since it is 00, the control logic proceeds to the processing step S2, in which the control device 8 is set to the fast-forward mode.

Here, the control device 8 is set to the cam mode and the fast-forward mode. Therefore, the decision step S
132 and S134, and then the judgment step S
At 135, it is determined that the camera is in the cam mode and the fast-forward mode, and the control logic proceeds to processing step S1. In the processing step S1, a rapid feed pulse distribution is performed, and the spindle 25 and the grindstone head 4 are rapidly fed in parallel according to a positioning logic described later, and quickly move from the initial position to the machining start position. When this movement is completed, the control logic returns to the start again.

Finally, in the processing step S100, the third line of the NC program is read, and the code is set to G01. Then, judgment steps S102, S104, S1
05, the control logic proceeds to the decision step S
It reaches 106. In determination step S106, since the read code is G01, the control logic proceeds to processing step S108, where the control device 8 is set to the grinding feed mode in processing step S108.

Here, the control device 8 is set to the cam mode and the grinding feed mode. Therefore, after passing through the determination steps S110, S120, and S132, it is determined in the determination step S134 that the cam mode and the grinding feed mode are set, and the control logic proceeds to the processing step S140.
Leads to. In processing step S140, cam generation pulse distribution is performed, and the spindle 25 and the grinding wheel head 4 are synchronously sent according to the above-described grinding processing conditions, and the cam is ground.

When the grinding of the cam is completed, the control logic returns to the start. Then, in accordance with the NC program in the fourth row and below, which is omitted in FIG. 2 described above, the spark-out processing which is the finishing processing of the cam is performed in processing step S144. In the above control logic, steps other than steps S1, S2, S105, and S135 are:
It is disclosed in Japanese Patent No. 2611123, and has a common step number. Therefore, those who want to know the control logic shown in FIG. 3 in more detail should refer to the publication.

The fast-forward pulse distribution executed in the above-described processing step S1 is performed according to the positioning logic shown in FIG. That is, first, in processing step S10, the second line (G0) of the aforementioned NC program (see FIG. 2)
(0 code) is called out. Then, as shown in the upper half of FIG. 5, a unit time (interpolation cycle) for sending the C axis to the machining start position at a constant speed.
The movement amount of the C-axis per hit is calculated. Then, NC
Based on the profile data P1234 declared in the first line (G101 code) of the program, the amount of movement per unit time of the X axis synchronized with the rotation of the C axis as shown by the thin curve in the lower half of FIG. Is calculated. That is, the amount of movement of the grinding wheel head 4 per unit time in synchronization with the rotation of the spindle 25 is calculated based on the profile data of the cam described above.

Next, in processing step S11 (see FIG. 4), based on the feed position and the feed speed specified in the second line of the NC program, the unit time for moving the X axis to the specified machining start position (see FIG. 4). The amount of movement (feed speed) per interpolation cycle is calculated. That is, as shown by a thin straight line in the lower half of FIG. 5, the movement amount per unit time of the grinding wheel head 4 moving from the initial position to the processing start position at a constant speed is calculated.

In processing step S12 (see FIG. 4), the movement amount of the X-axis per unit time calculated in step S11 is added to the movement amount of the X-axis per unit time calculated in step S10. . As a result, as shown by the bold line in the lower half of FIG. 5, the movement amount per unit time of the X axis to which the grinding wheel head 4 is to be actually sent is synthesized. This movement amount will be referred to as a combined movement amount.

Here, in the judgment step S13, it is judged whether or not the combined movement amount on the X axis exceeds the limit value VX _MAX of the movement amount per unit time on the X axis. When the synthesis amount of movement in the X-axis has exceeded the limit value VX _MAX, the positioning logic proceeds to processing step S15 for performing abnormality processing, the control unit 8, feed speed commanded by the preceding code G00 is too large To the operator on the CRT display,
The feed of the spindle 25 and the wheel head 4 is stopped. Conversely, X
If the synthesis amount of movement of the shaft does not exceed the limit value VX _MAX is normal, positioning logic in this case proceeds to the next processing step S14.

In the next processing step S14, based on the movement amount of the C-axis per unit time and the combined movement amount of the X-axis, the spindle motor and the X-axis motor 19 (see FIG. 1) which are servo motors are sent. A pulse output is sent. as a result,
Again, as shown by the thick lines in the upper and lower graphs of FIG.
The rotation of the wheel and the feed of the grinding wheel head 4 are performed quickly and in parallel.

In the last determination step S16, it is determined whether or not the spindle 25 and the grindstone head 4 have completed the movement to the machining start position for each cycle, and the above-described steps S10 to S14 are performed until it is determined that the movement has been completed. Is repeated. As a result, the rotation angle position of the spindle 25 and the feed position of the grindstone table 4 reach the machining start position and stop, and thereafter, the grinding is performed.

(Effects of the First Embodiment) Since the control device 8 incorporates the fast-forward means having the above functions as control logic, the following effects are exhibited by the grinding machine of the present embodiment. You. That is, before starting the grinding, the spindle 2
In parallel with the operation of rotating the non-round workpiece W by 5 and positioning it at the processing start position, the grinding wheel is adjusted while adjusting the advance / retreat position of the grinding wheel base 4 so that the grinding wheel 42 does not contact the non-round workpiece W. The table 4 is rapidly moved to the processing start position. Therefore, since the positioning of the main spindle 25 and the positioning of the grindstone table 4 are performed in parallel, the time required for the positioning operation immediately before the processing is greatly reduced, and the time required for the positioning operation is almost halved. This effect
This is apparent from a comparison between FIG. 5 showing the positioning operation of the present embodiment and FIG. 7 showing the positioning operation of the prior art.

Therefore, according to the grinding machine of the present embodiment,
The positioning operation of the non-round workpiece W before machining is performed in a short time, and the cycle time is shortened.
As a result, there is an effect that the productivity of the grinding machine can be improved at low cost only by changing the control program of the control device 8. (Modification 1 of Embodiment 1) As Modification 1 of this embodiment, the content of the abnormality processing step S15 shown in FIG. 4 is revised again, and the operation of the grinding machine is continued without stopping the C-axis and the X-axis. It is possible to implement a grinding machine with a possible control device 8.

In this modification, the grinding step S13
The retreat speed of the stone bed 4 is the limit value VX _MAXJudge if exceeds
If the rotation has been performed, the rotation of the main shaft 25 is performed in the processing step S15.
The speed is properly reduced and the retreat speed of the grinding wheel head 4 is below the limit value.
Set below. Conversely, the retreat speed of the grinding wheel head 4 is slow.
If it is determined that the limit value is exceeded,
The rotation of the main shaft 25 is set so that the retreat speed is less than the limit value.
The speed is properly reduced.

Therefore, according to this modification, the grinding wheel head 4
Even when it is determined that the retreat speed exceeds the limit value, the operation of the grinding machine can be continued without abnormal stop. Conversely, in the present modified embodiment, when it is determined in decision step S13 that the forward speed of the grinding wheel head 4 exceeds the limit value VX _MAX , the forward speed of the grinding wheel head 4 is set to the limit value in processing step S15. Is done. That is, when it is determined that the forward speed of the grinding wheel head 4 exceeds the limit value, the grinding wheel head 4 is sent forward at the limit value of the forward speed (full speed).

Therefore, according to this modification, even when it is determined that the forward speed of the grinding wheel head 4 exceeds the limit value, the operation of the grinding machine can be continued without abnormal stop. . [Embodiment 2] (Structure and operation and effect of Embodiment 2) A non-round workpiece machining apparatus according to Embodiment 2 of the present invention is obtained by replacing the grinding machine of Embodiment 1 or its modification 1 with an NC lathe. is there. That is, in the NC lathe of the present embodiment, instead of the grindstone table 4, a tool table for holding a tool as a tool is attached so as to be able to advance and retreat in the X-axis direction, and other parts are substantially the same as those of the first embodiment.
Or, it has a configuration similar to that of Modification 1. Also,
The control device 8 also has control logic that is substantially the same as that of the first embodiment or its modification 1.

Therefore, according to the NC lathe of the present embodiment, the same effects as those of the embodiment 1 or its modification 1 can be obtained. (Modification of the Second Embodiment) The present invention is applicable to another NC machining apparatus provided with a tool table holding another tool in place of the cutting tool instead of the NC lathe of the second embodiment so as to be able to advance and retreat. The same operation and effect as those of the embodiments can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a grinding machine according to a first embodiment.

FIG. 2 is an NC program list of the grinding machine according to the first embodiment.

FIG. 3 is a flowchart illustrating control logic of the grinding machine according to the first embodiment.

FIG. 4 is a flowchart illustrating positioning logic of the grinding machine according to the first embodiment.

FIG. 5 is a time chart showing the positioning operation of the grinding machine according to the first embodiment.

FIG. 6 is a schematic view showing a positioning operation of a grinding machine according to a conventional technique.

FIG. 7 is a time chart showing a positioning operation of a grinding machine according to a conventional technique.

[Explanation of symbols]

1: Bed 13: Guide rail 14: Ball screw 15: Z
Shaft motor 17: Guide rail 18: Ball screw 19: X
Axis motor 2: Spindle table 23: Tailstock 24: Spindlehead 25: Spindle 251: Reference pin
26: Truer 4: Wheel head 42: Wheel 43: Wheel shaft 46: Wheel motor 8: Control device

Claims (4)

[Claims] 1. A headstock having a spindle that holds and rotates a non-round workpiece and a tool that processes the non-round workpiece, and is relatively movable in a direction intersecting with the spindle. A non-circular workpiece processing apparatus having a tool table, and a control device for numerically controlling the spindle and the tool table, wherein the control device includes: In positioning the tool stand, in parallel with the operation of driving the non-circular workpiece by the main shaft and positioning it at a predetermined rotation angle position,
A non-circular workpiece machining apparatus, comprising: a rapid traverse means for moving the tool platform to a predetermined position while adjusting the advance / retreat position of the tool platform so that the tool does not contact the non-round workpiece. 2. The machine according to claim 1, wherein the control device controls the rotation of the spindle and the reciprocation of the tool base based on profile data when processing the non-round workpiece. The non-circular workpiece according to claim 1, wherein the advance / retreat position of the tool base is determined as a combination of the rapid traverse movement of the tool base and the travel distance of the tool base based on the profile data associated with the rapid traverse movement of the spindle. Processing equipment. 3. The rapid traverse means, when it is calculated that the retreat speed of the tool stand exceeds the limit value, appropriately reduces the rotational speed of the spindle to reduce the retreat speed of the tool stand. The non-circular workpiece processing apparatus according to claim 2, wherein the apparatus is set to be equal to or less than a limit value. 4. The method according to claim 2, wherein said fast-forward means sets said advance speed of said tool base to said limit value when it is calculated that said advance speed of said tool base exceeds said limit value. Non-circular workpiece processing equipment.