JP3682832B2 - Non-circular workpiece processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of NC machine tools, and more specifically, NC grinders and NC lathes that perform grinding or cutting on non-round workpieces such as camshafts and crankshafts. It belongs to the technical field of numerically controlled automatic processing equipment.
[0002]
[Prior art]
Taking a grinding machine as an example of a prior art non-circular workpiece processing apparatus, the position setting of the spindle and the grindstone head before starting processing in the grinding machine will be described.
In the NC grinder, the rotational movement of the spindle that holds and rotates the workpiece and the advancing and retreating movement of the grinding wheel head in the direction perpendicular to the spindle axis are controlled synchronously, and non-round workpieces such as camshafts There is one that made it possible to grind. In this type of grinding machine, when a non-round workpiece is attached to the main shaft and machining is started, a grindstone is placed at the next location to be ground among non-round workpieces that have multiple locations to be ground. When moving, it is necessary to position the grinding wheel base as a tool base and the spindle. That is, for the purpose of completing the preparation by setting the position immediately before starting the grinding process, a positioning operation for positioning the rotational angle position (phase) of the spindle and the advancing / retreating position of the grindstone base is required.
[0003]
In this positioning operation, interference (contact) between the convex portion of the non-round workpiece and the grindstone as a tool must be avoided. Therefore, as shown in FIGS. 6 and 7, first, positioning is performed to set the rotation angle position of the spindle to a predetermined position, and then the grindstone base is advanced to a predetermined machining preparation completion position. Positioning is performed.
[0004]
[Problems to be solved by the invention]
However, in the conventional grinding machine, since the positioning of the grindstone is performed after the spindle is positioned, the positioning operation before the grinding process takes time, which causes the cycle time to increase.
Accordingly, an object of the present invention is to provide a non-circular workpiece processing apparatus in which positioning operation before processing of a non-circular workpiece is performed in a short time and the cycle time is shortened.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the inventor has invented the following means.
(First means)
The first means of the present invention is the non-round workpiece processing apparatus according to claim 1.
Here, the non-circular workpiece is a workpiece that needs to be processed into a shape of an outer peripheral surface different from a concentric circle centered on the main axis, such as a camshaft or a crankshaft. Further, the non-circular workpiece processing apparatus mainly refers to an NC grinder, but is a concept including other NC processing apparatuses such as an NC lathe.
[0006]
This means has a control device that numerically controls drive means such as motors provided in a non-round workpiece processing apparatus such as a grinding machine, and this control device has fast-forward means as a numerical control program. The rapid traverse means has a function of performing the positioning of the spindle and the positioning of the tool base in parallel when positioning the spindle and the tool base as preparation for starting the machining of the non-round workpiece.
[0007]
That is, in this means, before starting the machining, in parallel with the operation of rotationally driving the non-circular workpiece by the spindle and positioning it at a predetermined rotational angle position, the tool is prevented from contacting the non-circular workpiece. The tool table is fast-forwarded to a predetermined position while adjusting the advance / retreat position of the table. Therefore, in this means, since the positioning of the spindle and the positioning of the tool base are performed in parallel, the time required for the positioning operation immediately before the machining is greatly shortened and generally halved.
[0008]
Therefore, according to this means, the positioning operation before machining the non-round workpiece can be performed in a short time, and the cycle time can be shortened. As a result, it is possible to improve the productivity of the non-round workpiece processing apparatus at low cost simply by changing the control program of the control apparatus.
(Second means)
The second means of the present invention is the non-round workpiece processing apparatus according to claim 2.
[0009]
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 machining 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 base as a combination of the rapid traverse movement amount of the tool base and the travel amount of the tool base based on the profile data accompanying the rapid traverse movement amount of the spindle. .
[0010]
That is, the advancing / retreating position of the tool table is determined by the fast-forwarding means as a combination of the rapid-feed movement amount of the tool table and the movement amount of the tool table based on the profile data accompanying the rapid-feed movement amount of the spindle. As a result, since the advance / retreat position of the tool table is set with a small amount of calculation, it becomes easier to perform the positioning operation before processing the non-round workpiece in real time.
[0011]
Therefore, according to this means, in addition to the effect of the first means described above, there is an effect that it becomes easier to perform the positioning operation before processing the non-round workpiece in real time.
(Third means)
The third means of the present invention is the non-circular workpiece processing apparatus according to claim 3.
[0012]
In this means, the rapid traverse means acts to appropriately reduce the spindle rotation speed and set the tool table retraction speed below the limit value when the retreat speed of the tool table exceeds the limit value. have. In other words, in this method, when the tool table retraction speed is calculated to exceed the limit value, the spindle rotation speed is appropriately adjusted so that the tool table retraction speed is less than the limit value. Reduced.
[0013]
Therefore, according to this means, in addition to the effect of the above-mentioned second means, even when it is calculated that the retreating speed of the tool table exceeds the limit value, the non-circular workpiece processing apparatus can There is an effect that driving can be continued.
(Fourth means)
According to a fourth aspect of the present invention, there is provided the non-round workpiece processing apparatus according to the fourth aspect.
[0014]
In this means, the rapid feed means has an action of setting the advance speed of the tool table to the limit value when it is calculated that the advance speed of the tool table exceeds the limit value. That is, when it is calculated that the advance speed of the tool table exceeds the limit value, the tool table is sent forward at the limit value (full speed) of the advance speed.
Therefore, according to this means, in addition to the effect of the above-mentioned second means, even when it is calculated that the advance speed of the tool table exceeds the limit value, the non-circular workpiece processing apparatus of the non-circular workpiece processing apparatus can be obtained without causing an abnormal stop. There is an effect that driving can be continued.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The embodiments of the non-circular workpiece processing apparatus of the present invention will be described clearly and sufficiently in the following examples so that a person skilled in the art can understand that the embodiments can be implemented.
[Example 1]
(Configuration of Example 1)
As a non-round workpiece processing apparatus according to Embodiment 1 of the present invention, a grinding machine will be described as an example as shown in FIG. That is, the grinding machine of the present embodiment includes a spindle stock 24 having a spindle 25 that holds and rotates a non-round workpiece W, and a grinding wheel 42 as a grinding tool around a grinding wheel axis parallel to the spindle 25. There is a grindstone base 4 as a tool base that is pivotally supported and rotationally driven and can relatively move back and forth in a direction orthogonal to the main shaft 24, and a control device 8 that numerically controls the main shaft 24 and the grindstone base 4.
[0016]
The headstock 24 and the tailstock 23 are mounted on the spindle table 2 so as to face each other, and the headstock 24 that sandwiches the non-round workpiece W between the spindle 25 and the tailstock 23 is the spindle table. 2 is fixedly equipped. Between the end of the non-circular workpiece W on the main shaft 25 side and the main shaft 25, a reference pin 251 for making the rotation angle position (phase) of the main shaft 25 coincide with the rotation angle position of the non-round workpiece W is provided. It is fixed.
[0017]
The spindle table 2 is movable in the Z-axis direction along a guide rail 13 formed on the bed 1 and is moved by a ball screw 14 that is rotationally driven by a Z-axis motor 15. Therefore, the main shaft 25 is movable in the Z-axis direction with respect to the grindstone table 4.
Here, an axis indicating parallel movement along the main axis of the headstock 24 is referred to as a Z axis. Further, the rotation axis of the main shaft 25 is referred to as a C axis, and the C axis is an axis that indicates a rotational motion around the main axis 25. In addition, on the side surface of the head stock 24 on the side of the grindstone table 4, a truer 26 having a disk-shaped cutting blade that is rotationally driven by a motor is fixedly equipped.
[0018]
On the other hand, the grindstone table 4 includes a rotating disc-shaped grindstone 42 as a tool, a grindstone shaft 43, and a grindstone motor 46 that rotationally drives both 42 and 43, and the guide rail 17 formed on the bed 1. Along the X axis direction. Here, the X-axis is an axis that is orthogonal to the main shaft 25 and faces the direction of the main shaft 25, and indicates the parallel movement of the grindstone table 4. The grinding wheel base 4 is fed in the X-axis direction by a ball screw 18 that is rotationally driven by an X-axis motor 19. Therefore, the grindstone platform 4 can move in the X-axis direction with respect to the main shaft 25.
[0019]
The spindle head 24, the spindle 25, and the grinding wheel head 4 are all numerically controlled by the control device 8 precisely and quickly according to a predetermined control program. When positioning the spindle 25 and the grindstone base 4 in preparation for starting the machining of the non-round workpiece W, the control device 8 rotationally drives the non-round workpiece W by the spindle 25 to a predetermined rotational angle position. In parallel with the positioning operation, fast-feed means is provided for feeding the grindstone table 4 to a predetermined position while adjusting the advancing / retreating position of the grindstone table 4 so that the grindstone 42 does not contact the non-circular workpiece W.
[0020]
This fast-forward means has a function of determining the advance / retreat position of the grindstone table 4 as a combination of the advance / retreat position synchronized with the rotation angle position of the main shaft 25 and the advance / retreat position synchronized with the rotation angle position of the non-circular workpiece W. This fast-forwarding means is stored in the control device 8 as a numerical control program (NC program).
(Operation of Example 1)
Since the grinding machine of the present embodiment is configured as described above, the following operational effects are exhibited. The operation of the grinding machine of the present embodiment will be described by taking as an example the case where cam grinding of the camshaft is performed as the non-true circular workpiece W.
[0021]
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 a non-circular workpiece W, machining start positions and moving speeds of the X axis and the C axis. It includes a second line to be set and a third line to set grinding conditions.
That is, first, when the first row N001 is executed, the code G101 is read and the control device 8 is set to the cam mode to read the profile data P1234 for grinding the cam of the camshaft which is a non-round workpiece. Thus, the control device 8 is set.
[0022]
Next, when the second row N002 is executed, the code G00 is read and the control device 8 is set to the rapid feed mode, the feed conditions of the X axis and the C axis are read, and the grinding wheel base is mainly based on the feed conditions. 4 and the spindle 25 are fed. The feed condition is defined by a feed speed and a machining start position at which the grindstone table 4 and the spindle 25 are fed from an initial position that is a standby position to a machining start position that is a preparation position for starting grinding.
[0023]
The feed conditions in this case are such that the feed speed of the X-axis is basically 5000 and the grindstone table 4 is sent to the feed position -30, and the rotation speed of the C-axis is 50 and sent to the 0 ° position. Is set. Since the X-axis and C-axis feeds in this fast-forward mode are the main part of the present invention, they will be described in more detail later with reference to FIGS.
[0024]
Finally, when the third row N003 is executed, the code G01 is read and the cam is ground. The grinding conditions in this case are as follows. The initial cut amount of the X axis is 0.1, the cut amount per one rotation of the main shaft is 0.1, the grinding speed per one rotation of the main shaft is 0.1, and the main shaft rotation speed 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.
[0025]
First, in process step S100, the first line of the NC program is read and the code is set to G101. Then, after passing through steps S102, S104, S105, S106, and S110, the control logic reaches a determination step S120. In the determination step S120, since the read code is G101, the control logic proceeds to the processing step S121, and in the processing step S121, the control device 8 is set to the cam mode. Thereafter, the control logic passes through the remaining decision steps and returns to the start.
[0026]
Next, in process step S100, the second line of the NC program is read and the code is set to G00. Then, after passing through steps S102 and S104, the control logic reaches a determination step S105. In the determination step S105, since the read code is G00, the control logic proceeds to the processing step S2, and the control device 8 is set to the fast-forward mode in the processing step S2.
[0027]
Here, the control device 8 is set to the cam mode and the fast-forward mode. Therefore, after passing through the determination steps S132 and S134, it is determined in the determination step S135 that it is in the cam mode and the fast-forward mode, and the control logic reaches the processing step S1. In the processing step S1, fast feed pulse distribution is performed, and the spindle 25 and the grindstone table 4 are fast fed in parallel according to the positioning logic described later, and quickly move from the initial position to the machining start position. When this movement is complete, the control logic returns to the start again.
[0028]
Finally, the third line of the NC program is read in processing step S100, and the code is set to G01. Then, after passing through the determination steps S102, S104, and S105, the control logic reaches the determination step S106. In the determination step S106, since the read code is G01, the control logic proceeds to the processing step S108, and the control device 8 is set to the grinding feed mode in the processing step S108.
[0029]
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 in effect, and the control logic reaches the processing step S140. In processing step S140, cam generation pulse distribution is performed, and the main shaft 25 and the grindstone table 4 are sent in synchronization according to the above-described grinding conditions, and cam grinding is performed.
[0030]
When the cam grinding is finished, the control logic returns to the start. Then, in accordance with the NC program in the fourth and subsequent rows, which is omitted in FIG. 2 described above, a spark-out process, which is a cam finishing process, is performed in process step S144.
Of the above control logic, steps other than steps S1, S2, S105, and S135 are disclosed in Japanese Patent No. 2611123, and step numbers are also common. Therefore, for those who want to know the control logic shown in FIG. 3 in more detail, refer to this publication.
[0031]
Now, 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 process step S10, the C-axis feed condition set in the second line (G00 code) of the NC program (see FIG. 2) is called. Then, as shown in the upper half of FIG. 5, the amount of movement of the C axis per unit time (interpolation cycle) for sending the C axis to the machining start position at a constant speed is calculated. Then, based on the profile data P1234 declared in the first line (G101 code) of the NC program, as shown in the thin curve in the lower half of FIG. 5, per unit time of the X axis synchronized with the rotation of the C axis. Is calculated. That is, the amount of movement per unit time of the grindstone table 4 synchronized with the rotation of the spindle 25 is calculated based on the cam profile data described above.
[0032]
Next, in processing step S11 (see FIG. 4), a unit time (interpolation period) for moving the X axis to the designated machining start position based on the feed position and feed speed designated in the second line of the NC program. The amount of movement (feed speed) per hit is calculated. That is, as shown by the thin straight line in the lower half of FIG. 5, the amount of movement per unit time of the grindstone table 4 that moves from the initial position to the machining start position at a constant speed is calculated.
[0033]
In processing step S12 (see FIG. 4), the movement amount per unit time of the X axis 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 thick line in the lower half of FIG. 5, the movement amount per unit time of the X axis to which the grindstone table 4 is actually sent is synthesized. This movement amount is referred to as a combined movement amount.
[0034]
Here, in the determination step S13, it is determined whether or not the combined movement amount of the X axis exceeds the limit value VX _MAX of the movement amount per unit time of the X axis. If the combined movement amount of the X-axis exceeds the limit value VX _MAX , the positioning logic proceeds to processing step S15 for performing an abnormal process, and the control device 8 has the feed speed commanded by the above-mentioned code G00 too large. The effect is notified to the operator by a CRT display, and the feeding of the spindle 25 and the grinding wheel base 4 is stopped. Conversely, it is normal that the combined movement amount of the X-axis does not exceed the limit value VX _MAX , and in this case, the positioning logic proceeds to the next processing step S14.
[0035]
In the next processing step S14, a pulse output is sent to the spindle motor and the X-axis motor 19 (see FIG. 1), which are servo motors, based on the aforementioned movement amount per unit time of the C-axis and the combined movement amount of the X-axis. Sent. As a result, as indicated by thick lines in the upper and lower graphs in FIG. 5 again, the rotation of the spindle 25 and the feed of the grindstone table 4 are quickly performed in parallel.
[0036]
In the final determination step S16, it is determined whether or not the spindle 25 and the grindstone table 4 have finished moving to the machining start position for each cycle, and the above-described steps S10 to S14 are repeated until it is determined that the movement has been completed. . As a result, the rotational angle position of the spindle 25 and the feed position of the grindstone table 4 reach the machining start position and stop, and then grinding is performed.
[0037]
(Effect of Example 1)
Since the control device 8 has built-in fast-forwarding means that exhibits the above functions as control logic, the grinding machine of this embodiment exhibits the following effects.
That is, before starting the grinding process, in parallel with the operation of rotationally driving the non-circular workpiece W by the spindle 25 and positioning the non-circular workpiece W at the machining start position, the grinding wheel base is set so that the grindstone 42 does not contact the non-circular workpiece W. The grindstone table 4 is fast-forwarded to the machining start position while adjusting the forward / backward position of 4. 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 machining is greatly shortened and generally halved. This effect is apparent when comparing FIG. 5 showing the positioning operation of this embodiment with FIG. 7 showing the positioning operation of the prior art.
[0038]
Therefore, according to the grinding machine of the present embodiment, the positioning operation before the processing of the non-round workpiece W is performed in a short time, and the cycle time is shortened. As a result, 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 Example 1)
As a modification 1 of the present embodiment, the content of the abnormality processing step S15 shown in FIG. 4 is revised again, and grinding with a control device 8 capable of continuing the operation of the grinding machine without stopping the C axis and the X axis. A board can be implemented.
[0039]
In this modified embodiment, when the reverse speed of the wheel head 4 in the determination step S13 is determined to exceed the limit value VX _MAX, the rotational speed of the spindle 25 in the process step S15 is properly reduced by the wheel head 4 The reverse speed is set below the limit value. In other words, when it is determined that the reverse speed of the grindstone table 4 exceeds the limit value, the rotational speed of the spindle 25 is appropriately reduced so that the reverse speed of the grindstone table 4 is less than the limit value. Is done.
[0040]
Therefore, according to this modification, even if it is determined that the retraction speed of the grindstone table 4 exceeds the limit value, there is an effect that the operation of the grinding machine can be continued without causing an abnormal stop.
On the contrary, in this modification, when it is determined in the determination step S13 that the advance speed of the grindstone table 4 exceeds the limit value VX _MAX , the advance speed of the grindstone table 4 is set to the limit value in the processing step S15. Is done. That is, when it is determined that the forward speed of the grindstone table 4 exceeds the limit value, the grindstone table 4 is fed forward at the limit value (full speed) of the forward speed.
[0041]
Therefore, according to this modification, even when it is determined that the forward speed of the grindstone table 4 exceeds the limit value, there is an effect that the operation of the grinding machine can be continued without causing an abnormal stop.
[Example 2]
(Configuration and effect of Example 2)
The non-round workpiece processing apparatus according to the second embodiment of the present invention is obtained by replacing the grinding machine according to the first embodiment or the modification 1 thereof with an NC lathe. That is, in the NC lathe of this embodiment, instead of the grinding wheel base 4, a tool base for holding a cutting tool as a tool is attached so as to be able to advance and retreat in the X-axis direction. The configuration is the same as in the first aspect. Also, the control device 8 has substantially the same control logic as that of the first embodiment or the modification 1 thereof.
[0042]
Therefore, according to the NC lathe of the present embodiment, the same effects as those of the first embodiment or the modification 1 thereof can be obtained.
(Modification of Example 2)
In place of the NC lathe according to the second embodiment, other NC machining apparatuses equipped with a tool table that holds other tools in place of the cutting tool are capable of moving back and forth. An effect is obtained.
[Brief description of the drawings]
FIG. 1 is a plan view showing the configuration of a grinding machine as Example 1. FIG. 2 is a NC program list of the grinding machine of Example 1. FIG. 3 is a flowchart showing control logic of the grinding machine of Example 1. Flowchart showing the 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 diagram showing the positioning operation of the grinding machine according to the prior art. Time chart showing the positioning operation of a grinding machine according to the prior art
1: Bed 13: Guide rail 14: Ball screw 15: Z-axis motor 17: Guide rail 18: Ball screw 19: X-axis motor 2: Spindle table 23: Tailstock 24: Spindle base 25: Spindle 251: Reference pin 26 : Truer 4: Grinding wheel base 42: Grinding wheel 43: Grinding wheel shaft 46: Grinding wheel motor 8: Control device

Claims (4)

A headstock with a spindle that rotates and holds a non-round workpiece;
A tool table that holds a tool for machining the non-circular workpiece and is capable of moving back and forth in a direction intersecting the main axis;
A controller for numerically controlling the spindle and the tool table;
In a non-round workpiece processing apparatus having
In preparation for starting the machining of the non-circular workpiece, the control device rotationally drives the non-circular workpiece with the spindle to position it at a predetermined rotational angle position. In parallel with the operation to perform, there is a fast-forwarding means for adjusting the advancing / retreating position of the tool table so that the tool does not contact the non-circular workpiece, and sending the tool table to a predetermined position.
A non-circular workpiece processing apparatus characterized by that. The control device controls the rotation of the spindle and the advance / retreat of the tool table based on profile data when processing the non-circular workpiece.
The rapid feed means determines an advance / retreat position of the tool table as a combination of a rapid feed movement amount of the tool table and a movement amount of the tool table based on the profile data associated with the rapid feed movement amount of the spindle.
The non-circular workpiece processing apparatus according to claim 1. When it is calculated that the retreating speed of the tool table exceeds the limit value, the rapid feed means appropriately reduces the rotation speed of the spindle and sets the retreating speed of the tool table to be equal to or less than the limit value. To
The non-round workpiece processing apparatus according to claim 2. The rapid traverse means sets the advance speed of the tool table to the limit value when it is calculated that the advance speed of the tool table exceeds the limit value;
The non-round workpiece processing apparatus according to claim 2.

Images