JP2006192516A - Machine tool, and work measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is required to prepare a special measuring means when measuring the dimension of a work machined, which causes in increase in the cost. <P>SOLUTION: This work measuring device is provided with a feed movement means giving a relative movement to a spindle 17 for mounting a working tool and a worktable 12 for fixing the work 15, and a position detecting sensor detecting position information accompanied by the operation of the feed movement means; and is incorporated in a machine tool. This work measuring device is further provided with a contact 18 mounted on the spindle 17 and pushed against the measuring position of the work 15, a torque sensor detecting a change in a driving torque when driving the feed movement means for making the contact 18 push against the measuring position of the work, and a control means stopping the operation of the feed movement means when an amount of the torque change detected by the torque sensor 20 exceeds a predetermined value, and calculating a distance between two measurement positions of the work 15 based on the detecting information from the position detecting sensor at that time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a workpiece measuring device for measuring a workpiece dimension, a machine tool incorporating the workpiece measuring device, and a workpiece measuring method.

  In order to obtain a product with a highly accurate shape required for various types of cutting, it is difficult to finish the final product with a single cutting process. It is necessary to divide the cutting process several times. In order to confirm the machining shape of the cut workpiece, the operator removes the workpiece fixed on the work table of the machine tool, and confirms the dimensions using a measuring instrument such as a caliper or a tool microscope. At this time, if the machined workpiece has not reached the required design accuracy, the workpiece is again fixed to the work table of the machine tool, and the necessary cutting is resumed. Then, such a series of operations are repeated until the required accuracy is reached.

  A cutting method disclosed in Patent Document 1 is known in order to efficiently advance a series of operations as described above on a workpiece that requires high-precision machining. In this cutting method, measuring means for measuring the dimensions of the work held by the chuck through a contactor that is detachably attached to the main spindle by automatic tool changing means, and position adjustment for adjusting the relative position between the main spindle and the work. Control means for controlling the means on the basis of the measurement result of the measuring means, and measuring the dimension of the workpiece by the measuring means and cutting the workpiece by the cutting tool until the dimension of the workpiece measured by the measuring means reaches a specified dimension. The process is repeated.

Japanese Patent Laid-Open No. 5-146949

  In the case of the cutting method described in Patent Document 1, it is necessary to additionally provide a measuring means using a contact with respect to the accessory equipment of an existing machine tool.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a workpiece measuring apparatus that measures the dimensions of a workpiece using various elements incorporated in the machine tool as much as possible without incorporating an independent dimension measuring device for the machine tool, and the workpiece measurement. It is an object of the present invention to provide a machine tool incorporating a device and a workpiece measuring method.

  According to a first aspect of the present invention, a work table to which a workpiece is fixed, a spindle on which a machining tool for performing predetermined machining on the workpiece is interchangeably mounted, and the spindle and the work table are relative to each other. A feed moving means for giving a movement and performing a predetermined machining on the work fixed to the work table, and detecting information on a relative position between the spindle and the work table in accordance with the operation of the feed moving means. A workpiece measuring device incorporated in a machine tool having a position detection sensor for measuring the dimensions of a workpiece, and pressed against a measurement position of a workpiece mounted on a spindle of the machine tool and fixed to the workpiece table And a torque sensor that detects a change in driving torque when the feed moving means is driven so that the contact is pressed against the measurement position of the workpiece. And when the amount of torque change detected by the torque sensor exceeds a predetermined value, the operation of the feed moving means is stopped, and based on detection information from the position detection sensor at this time, Control means for calculating the distance between the measurement positions is provided.

  Further, the second form of the present invention is a work table on which a work is fixed, and a spindle on which a work tool for performing predetermined processing on the work fixed on the work table is replaceably mounted, Feed movement means for giving a relative movement between the spindle and the work table to perform predetermined machining on the work fixed to the work table, and the spindle and the work table accompanying the operation of the feed movement means A contact detection device that includes a position detection sensor that detects information related to a relative position of the workpiece, and a contactor mounted on a spindle of the machine tool and pressed against a measurement position of a workpiece fixed to the worktable, and the contactor A torque sensor that detects a change in driving torque when the feed moving means is driven so as to press against the measurement position of the workpiece, and the torque sensor. When the amount of torque change detected by the servo exceeds a predetermined value, the operation of the feed moving means is stopped, and based on detection information from the position detection sensor at this time, between the two measurement positions of the workpiece And a control means for calculating a distance.

  In the first and second aspects of the present invention, the feed moving means is operated so that the contact mounted on the spindle of the machine tool presses against the first measurement position of the work fixed to the work table. The change in the driving torque of the feed moving means is detected by a torque sensor, and when the amount of change in the drive torque exceeds a predetermined value, the operation of the feed moving means is stopped, and the spindle and work table of the machine tool in this state The position detection sensor detects information related to the relative position. Next, the feed moving means is operated so that the contactor presses against the second measurement position of the workpiece, and a change in the driving torque at this time is detected by a torque sensor, and the amount of change in the driving torque exceeds a predetermined value. In this case, the operation of the feed moving means is stopped, and information on the relative position between the spindle of the machine tool and the work table in this state is detected by the position detection sensor. The control device calculates the distance between the two measurement positions of the workpiece based on the two position detection information from the position detection sensor thus obtained.

  According to a third aspect of the present invention, there is provided a step of mounting a contactor, which is pressed against a measurement position of a work fixed to a work table, on a spindle of a machine tool, and a first of the work in which the contact is fixed to the work table. Activating a feed moving means for providing relative movement between the spindle of the machine tool and the work table so as to press against the one measurement position; and when activating the feed movement means with respect to the first measurement position. Detecting a change in the driving torque of the machine tool, and when the amount of change in the driving torque exceeds a predetermined value, the operation of the feed moving means is stopped, and the spindle of the machine tool and the work table in this state are Detecting the information on the position, and the feed so that the contact is pressed against a second measurement position of the work fixed to the work table. A step of operating a moving means, a step of detecting a change in driving torque when the feed moving means is operated with respect to the second measurement position, and a case where the amount of change in the driving torque exceeds a predetermined value. Stopping the operation of the feed movement means, detecting information on the relative position between the spindle of the machine tool and the work table in this state, and calculating the distance between the two measurement positions of the work Is a workpiece measuring method characterized by

  In the first, second, and third embodiments of the present invention, the machine tool may be an NC machine tool, and may have three sets of feed moving means along three directions orthogonal to each other. Further, the distance between the two measurement positions of the workpiece may be a distance along the relative movement direction between the spindle of the machine tool and the work table by the feed moving means.

  According to the workpiece measuring device of the present invention and the machine tool in which the workpiece measuring device is incorporated, the contact mounted on the spindle of the machine tool and pressed against the measurement position of the workpiece fixed to the work table, and the contact A torque sensor that detects a change in driving torque when the feed moving means is driven so as to press against the measurement position of the workpiece, and when the amount of torque change detected by the torque sensor exceeds a predetermined value, the feed moving means Since the operation was stopped and the control means for calculating the distance between the two measurement positions of the workpiece based on the detection information from the position detection sensor at this time was incorporated into the machine tool, the dimension of the workpiece was measured. Eliminates the need to incorporate a separate measuring device into the machine tool to measure workpiece dimensions, incorporates a torque sensor into an existing machine tool, At low cost control device only by a small improvement it was possible to measure the dimensions of the workpiece.

  According to the work measuring method of the present invention, the contact that is pressed against the measurement position of the work fixed to the work table is mounted on the spindle of the machine tool, and the first measurement position of the work with the contact fixed to the work table. The feed movement means for moving the spindle of the machine tool and the work table relative to each other is actuated to detect the change in the drive torque when the feed movement means is actuated with respect to the first measurement position. When the amount of change in drive torque exceeds a predetermined value, the feed movement means stops operating, and after detecting information on the relative position between the spindle of the machine tool and the work table in this state, the contact is fixed to the work table. The feed movement means is operated so as to press against the second measurement position of the workpiece, and the driving torque when the feed movement means is activated with respect to the second measurement position is When the amount of change in the drive torque exceeds a predetermined value, the operation of the feed moving means is stopped, and information on the relative position between the spindle of the machine tool and the work table in this state is detected. Since the distance between the two measurement positions is calculated, there is no need to incorporate an independent measuring device for measuring the workpiece dimensions into the machine tool, a torque sensor is incorporated into the existing machine tool, and a control device. It is possible to measure the dimensions of the workpiece at low cost by making a small improvement.

  Embodiments in which a machine tool according to the present invention is applied to a vertical machining center will be described in detail with reference to FIGS. 1 to 8, but the present invention is not limited to such embodiments and is described in the claims. Any change or modification encompassed by the disclosed concept of the present invention is possible, and can naturally be applied to other techniques belonging to the spirit of the present invention.

  FIG. 1 shows the front shape of the vertical machining center in this embodiment, FIG. 2 shows the right side shape thereof, and FIG. 3 shows the control block of the feed drive motor incorporated in this vertical machining center. That is, the base 11 of the vertical machining center 10 has a work table 12 movable in the left-right direction in FIG. 1 and a left-right direction in FIG. 2 and a column 14 that supports the spindle head 13 movably in the up-down direction in FIG. And are installed. The work table 12 on which the work 15 is fixedly supported is driven by an X direction (left and right direction in FIG. 1) feed drive motor 16X and a Y direction (left and right direction in FIG. 2) feed drive motor 16Y. Hold in any position above. The spindle head 13 is driven by a feed driving motor 16Z in the Z direction (vertical direction in FIG. 2). A spindle 17 that is driven and rotated by a spindle drive motor (not shown) incorporated in the spindle head 13 is attached to the spindle head 13 downward, and a desired tool and a contact 18 according to the present invention are not shown. ) To the lower end of the main shaft 17 in a replaceable manner.

  In each of the feed drive motors 16X to 16Z (hereinafter collectively referred to as 16), movement amounts of the work table 12 in the X direction and the Y direction in accordance with the operation of the feed drive motor 16 and the Z of the spindle head 13 are set. An encoder 19 for detecting the amount of directional movement and a torque sensor 20 for detecting a load associated with the operation of the feed drive motor 16 are connected to each other, and these detection signals control the operation of the feed drive motor 16. Each of them is transmitted to the control device 21. The torque sensor 20 detects a change in driving torque when the feed driving motor 16 is driven so that the contact 18 mounted on the main shaft 17 is pressed against the measurement position of the workpiece 15, and the control device 21 will be described later. Further, based on detection information from the encoder 19 as a position detection sensor according to the present invention, a distance between two measurement points of the work 15 mounted on the work table 12 is calculated.

  When measuring the dimensions of the workpiece 15 after cutting mounted on the workpiece table 12, chips and machining fluid adhering to the measurement surface are removed, and the tip is pressed against the measurement surface. The contactor 18 is used by being replaced with a cutting tool (not shown) attached to the main shaft 17. For example, when measuring the height from the work table 12 to the uppermost end surface of the work 15, the operation of the feed drive motor 16 is controlled according to the work procedure shown in FIG. That is, the tip of the contact 18 mounted on the main shaft 17 at the retracted position where there is no interference with the work 15 mounted on the work table 12 in step S1 is positioned right above the reference surface 22 on the work table 12. The work table 12 is moved so as to position the work 15 and the contact 18 with respect to the work table 12. Next, in step S2, the Z-direction feed drive motor 16Z is operated, and the spindle head 13 is slowly moved at a constant speed set in advance on the work table 12 side so that the contact 18 comes into contact with the reference surface 22 of the work table 12. In step S3, the output from the torque sensor 20 at this time is continuously read. In step S4, it is determined whether the torque change amount at this time is equal to or greater than a preset value. In a state where the tip of the contact 18 is not in contact with the reference surface 22 of the work table 12, the detected torque does not change beyond a predetermined amount, and therefore the Z-direction feed drive motor 16Z continues to operate. As shown in FIG. 5, when the tip of the contact 18 comes into contact with the reference surface 22 of the work table 12, the lowering of the spindle head 13 is suppressed. As a result, the amount of torque change suddenly increases, and the tip of the contact 18. It can be determined that is in contact with the reference surface 22 of the work table 12. Thus, when the torque change amount reaches a predetermined value or more, the process proceeds to step S5 to stop the operation of the Z-direction feed drive motor 16Z, and from the output of the encoder 19 of the Z-direction feed drive motor 16Z in this state, The control device 21 stores the Z-direction coordinate position of the tip of the contact 18 as shown in step S6.

  Thereafter, the process proceeds to step S7, and it is determined whether or not the acquisition of the Z-direction coordinate position of the tip of the contact 18 in step S6 is the second time. Since the first measurement is the first time, the spindle head 13 is again raised to the retracted position, and the process returns to the step S1, and the work table 12 is moved so that the contact 18 is positioned directly above the measurement surface 23 of the work 15. Then, the contactor 18 is positioned again. In step S2, the Z-direction feed drive motor 16Z is operated to lower the spindle head 13 toward the work table 12 at a constant speed so that the contact 18 abuts on the measurement surface 23 of the work 15, and step S3. In step S4, the output from the torque sensor 20 is read, and it is determined in step S4 whether or not the torque change amount is equal to or greater than a preset value. As shown in FIG. 6, when it is determined in step S4 that the tip of the contact 18 is in contact with the measurement surface 23 of the workpiece 15 and the torque change amount has reached a predetermined value or more, the process proceeds to step S5. The operation of the Z-direction feed drive motor 16Z is stopped, and the control device 21 stores the Z-direction coordinate position of the tip of the contact 18 at this time from the output of the encoder 19 of the Z-direction feed drive motor 16Z in step S6. In step S7, it is determined whether or not the Z-direction coordinate position of the tip of the contactor 18 is acquired for the second time. In this case, since it is the second acquisition, the process proceeds to step S8, the dimension of the work 15 along the Z direction is calculated from the previous coordinate position in the Z direction, and the result is output in step S9.

  In addition, if the coordinate data regarding the reference surface 22 of the work table 12 is stored in the control device 21 in advance, the above-described position measuring operation of the reference surface 22 of the work table 12 can be omitted. The movement of the work table 12 and the spindle head 13 for measuring the work 15 can be controlled by a control program using the control device 21 of the machining center 10.

  As shown in FIG. 7, when the work 15 has the protrusion 24, the height of the protrusion 24 can be measured. In this case, the height of the protrusion 24 can be measured from the Z-direction coordinates of the first measurement position indicated by the two-dot chain line and the Z-direction coordinates of the second measurement position indicated by the solid line. It is also possible to measure the dimension of the workpiece 15 in the X direction or the Y direction. For example, when measuring the width dimension along the X direction of the workpiece 15, as shown in FIG. 8 showing the measurement concept, the X direction coordinate of the tip of the contact 18 at the first measurement position indicated by a two-dot chain line and The width dimension along the X direction of the workpiece 15 can be measured from the X direction coordinates of the second measurement position indicated by the solid line. In this case, it goes without saying that the X-direction feed drive motor 16X and the encoder 19 and torque sensor 20 connected thereto are used.

1 is a front view illustrating an appearance of an embodiment in which a machine tool according to the present invention is applied to a vertical machining center. FIG. 2 is a side view of the vertical machining center shown in FIG. 1. FIG. 3 is a control block diagram of an embodiment of a workpiece measuring apparatus according to the present invention incorporated in the vertical machining center shown in FIGS. 1 and 2. It is a flowchart showing the workpiece | work measurement procedure in one Embodiment of the workpiece | work measuring method by this invention. FIG. 7 is a work conceptual diagram showing a state in the middle of measuring the workpiece height together with FIG. 6. FIG. 6 is a work conceptual diagram showing a state in the middle of measuring the workpiece height together with FIG. 5. It is a schematic diagram showing the measurement concept of the height with respect to another workpiece | work. It is a schematic diagram showing the measurement concept of the width | variety of a workpiece | work.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vertical machining center 11 Base 12 Work table 13 Spindle head 14 Column 15 Work 16X X direction feed drive motor 16Y Y direction feed drive motor 16Z Z direction feed drive motor 17 Spindle 18 Contact 19 Encoder 20 Torque sensor 21 Control device 22 Reference surface 23 Measuring surface 24 Projection

Claims (3)

A work table to which a workpiece is fixed, a spindle on which a machining tool for performing predetermined machining on the workpiece is exchangeably mounted, and a relative movement between the spindle and the work table is given and fixed to the work table. A machine tool having a feed moving means for performing predetermined machining on a given workpiece, and a position detection sensor for detecting information on a relative position between the spindle and the work table in accordance with the operation of the feed moving means. A workpiece measuring device for measuring the dimensions of a workpiece,
A contactor mounted on a spindle of the machine tool and pressed against a measurement position of a workpiece fixed to the worktable;
A torque sensor for detecting a change in driving torque when the feed moving means is driven so that the contact is pressed against the measurement position of the workpiece;
When the amount of torque change detected by the torque sensor exceeds a predetermined value, the operation of the feed moving means is stopped, and two measurement positions of the workpiece are detected based on detection information from the position detection sensor at this time. And a control means for calculating the distance between the workpiece measuring devices. A work table to which a work is fixed, a spindle on which a machining tool for performing predetermined machining on the work fixed to the work table is exchangeably mounted, and relative movement between the spindle and the work table. Position detection for detecting information relating to the relative position between the main spindle and the work table in accordance with the operation of the feed moving means, and a feed moving means for performing predetermined machining on the work fixed to the work table In a machine tool having a sensor,
A contactor mounted on a spindle of a machine tool and pressed against a measurement position of a workpiece fixed to the worktable;
A torque sensor for detecting a change in driving torque when the feed moving means is driven so that the contact is pressed against the measurement position of the workpiece;
When the amount of torque change detected by the torque sensor exceeds a predetermined value, the operation of the feed moving means is stopped, and two measurement positions of the workpiece are detected based on detection information from the position detection sensor at this time. And a control means for calculating the distance between the machine tools. Attaching a contactor pressed against the measurement position of the workpiece fixed to the worktable to the spindle of the machine tool;
Activating feed moving means for providing relative movement between the spindle of the machine tool and the work table so that the contact is pressed against a first measurement position of a work fixed to the work table;
Detecting a change in driving torque when the feed moving means is operated with respect to the first measurement position;
Stopping the operation of the feed movement means when the amount of change in the drive torque exceeds a predetermined value, and detecting information on the relative position between the spindle of the machine tool and the work table in this state;
Activating the feed moving means such that the contact presses against a second measurement position of a work fixed to the work table;
Detecting a change in driving torque when the feed moving means is operated with respect to the second measurement position;
When the amount of change in the drive torque exceeds a predetermined value, the operation of the feed moving means is stopped, and information on the relative position between the spindle of the machine tool and the work table in this state is detected to detect two of the workpieces. A workpiece measuring method comprising: calculating a distance between measurement positions.

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