JP2005262425A - Processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct the positional relationship between a grinding wheel and a work, by accurately measuring a grinding wheel diameter, even if a touch sensor cannot be arranged on the rotational axis of the grinding wheel. <P>SOLUTION: A diametrally unchangeable reference grinding wheel 22b is coaxially arranged with the grinding wheel 22a. Even if the rotational axis O of the grinding wheel 22a moves by thermal displacement, the reference grinding wheel 22b is similarly moved. As a result, a contact position Xa for contacting this reference grinding wheel 22b with a detecting pin 34 is determined, and next, a contact position Xb for contacting the touch sensor 50 with the detecting pin 34 is determined. A distance C up to the tip of the touch sensor 50 can be determined from the rotational axis O on the basis of these contact positions Xa and Xb. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a touch sensor for accurately grasping the positional relationship between a rotary tool and a workpiece in a machining apparatus that performs machining by relatively moving a tool table that rotatably supports a rotary tool and a table that supports the workpiece. And a processing apparatus having a detection pin.

  2. Description of the Related Art Conventionally, for example, a cylindrical grinder is known as a processing apparatus that performs processing by relatively moving a tool table that rotatably supports a rotating tool and a table that supports a workpiece. This cylindrical grinder performs a grinding process by rotatably supporting a grinding wheel as a rotary tool on a grinding wheel base and cutting the grinding wheel into a workpiece held rotatably on a table. In a cylindrical grinder with such a configuration, it is necessary to accurately control the cutting amount of the grinding wheel into the workpiece in order to carry out high-precision grinding. The grinding surface of the grinding wheel, that is, the workpiece side tip position of the grinding wheel changes due to wear and truing of the grinding wheel. For this reason, during the grinding process, the diameter of the grinding wheel is periodically detected to correct the positional relationship between the grinding wheel and the workpiece.

  In addition, when grinding a cam profile such as a camshaft, the grinding point between the grinding wheel outer periphery and the workpiece changes around the rotation axis along with the change in the grinding wheel diameter, resulting in a profile error. Therefore, in order to reduce the profile error, it is necessary to accurately obtain the grindstone diameter.

Patent Document 1 discloses a configuration for correcting the positional relationship between a grinding wheel and a workpiece, as shown in FIG. 1 of Patent Document 1, on a grinding wheel (7) rotation axis of a grinding wheel base (6). 24), and a detection pin (34) is projected from the table (3). Then, the grinding wheel (7) and the touch sensor (24) are periodically brought into contact with the detection pin (34), the movement of the grinding wheel (7) due to thermal displacement of the rotational axis is corrected, and the grinding wheel diameter is measured. A change in the grinding wheel diameter due to wear and truing of the grinding wheel (7) is detected, and the positional relationship between the grinding wheel (7) and the workpiece W is corrected.
JP-A-11-277428 (paragraph number 0014, FIGS. 1 and 2)

  As in Patent Document 1, in order to accurately measure the grinding wheel diameter of the grinding wheel (7), it is necessary to eliminate the influence of the movement amount due to the thermal displacement of the rotation axis. For this reason, in Patent Document 1, the touch sensor (24) is formed of a low thermal expansion material, one end of the touch sensor (24) is mounted on the rotation axis of the grinding wheel (7), and the rotation axis of the grinding wheel (7). The amount of movement is the same as the amount of movement due to thermal displacement.

  However, depending on the configuration of the cylindrical grinder, the installation position of the touch sensor (24) may not be on the rotation axis of the grinding wheel (7). in this case,

The distance between the mounting position of the touch sensor (24) and the rotational axis of the grinding wheel (7) is stored in advance as an offset amount. However, the amount of movement due to the thermal displacement of the rotational axis of the grinding wheel (7) and the mounting position of the touch sensor do not match the thermal displacement, and an error is generated in the offset amount stored in advance. The grinding wheel diameter could not be measured, and the processing accuracy could be deteriorated.
In addition, the grindstone diameter is obtained by calculation from the position of the rotation axis and the measured position of the circumferential surface of the grindstone, but the position of the rotation axis in the cutting direction relative to the workpiece is largely thermally displaced by the cutting feed every time. Since it is difficult to accurately determine the position of the rotational axis that has been thermally displaced, the grindstone diameter determined by calculation is also inaccurate.

  The present invention has been made to improve the conventional problems, and has an object to accurately measure the diameter of a grinding wheel that is a rotary tool and to accurately correct the positional relationship between the grinding wheel and a workpiece. And

  In order to solve the above-mentioned problems, the structural features of the invention according to claim 1 include a tool table on which a rotary tool is rotatably supported around a tool axis, a table for holding a workpiece, and an outer peripheral surface of the rotary tool. And / or a machining apparatus for machining a workpiece by moving the tool table and the table relative to each other in a direction to be separated from each other with respect to the position of the side surface of the tool. Alternatively, the reference tool having a known tool width, the detection pin fixed to the table, and the outer peripheral surface and / or the tool side surface of the reference tool are moved toward the detection pin, so that the outer peripheral surface and / or the tool side surface of the reference tool are Means for storing the position touched or cut into the detection pin as a reference position, and the outer peripheral surface of the rotary tool and / or when the rotary tool is moved from the reference position toward the detection pin. The position where the tool side surface is in contact with or cut into the reference pin is stored as a feed position, and a means for storing the amount of movement of the rotary tool from the reference position and the difference between the reference position and the feed position are obtained. And means for calculating the amount of wear of the rotary tool from the difference between the difference and the amount of movement, and means for determining the diameter and / or side surface position of the tool based on the amount of wear of the rotary tool. .

  Further, the structural feature of the invention according to claim 2 is that a reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance, a touch sensor that extends toward the table on a grindstone table, A detection pin fixed to the table so as to be able to contact the touch sensor, a reference tool contact position storage means for storing a contact position of the reference rotation tool to the detection pin, and a contact of the reference rotation tool to the detection pin Later, the contact surface of the detection pin is detected by a touch sensor, and the first contact position storage means for storing the contact position, the contact position stored in the reference tool contact position storage means, and the first contact position storage means are stored. A first relative distance calculating means for calculating a relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor based on the contact position, and a calculation by the first relative distance calculating means. A touch sensor distance calculating means for calculating a distance from the tool axis to the tip of the touch sensor from a measured relative distance and a diameter of the reference rotating tool, and a tool contact position for storing a contact position of the rotating tool to the detection pin After contact with the detection pin by the rotating tool with the storage means, the second contact position storage means for detecting the contact surface of the detection pin with a touch sensor and storing the contact position, and the tool contact position storage means. Second relative distance calculation means for calculating a relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the second contact position storage means and the second contact position storage means; The rotation based on the relative distance calculated by the relative distance calculation means and the distance from the tool axis to the tip of the touch sensor calculated by the touch sensor distance calculation means. Rotating tool diameter calculating means for calculating the diameter of the tool, and position changing means for changing the position of the outer peripheral surface of the rotating tool based on the diameter of the rotating tool calculated by the rotating tool diameter calculating means. is there.

  Further, the structural feature of the invention according to claim 3 is that a reference tool having a known diameter in advance and coaxially supported with the rotation axis of the rotary tool, and an X axis which is fixed to the table and extends along the X axis and the Z axis. To the detection pin and the Z-axis detection pin, side distance storage means for storing the distance from the tool center of the rotary tool to the side of the reference rotary tool or the rotary tool, and the X-axis detection pin by the outer peripheral surface of the reference rotary tool X-axis contact position storage means for storing the contact position, Z-axis contact position storage means for storing a contact position of the reference rotary tool or the side surface of the rotary tool to the Z-axis detection pin, a diameter of the reference tool, The rotary tool based on the distance from the tool center of the rotary tool stored in the side distance storage means to the side surface of the reference rotary tool or rotary tool, and the cutting position to the X-axis detection pin and Z-axis detection pin Craft Coordinate correction means for calculating the correction coordinates of the tool center is provided.

  Further, the structural feature of the invention according to claim 4 is that a reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance, a touch sensor that extends toward the table on a grindstone table, A detection pin fixed to the table so as to be able to contact the touch sensor, a reference tool contact position storage means for storing a contact position of the reference rotation tool to the detection pin, and a contact of the reference rotation tool to the detection pin Later, the contact surface of the detection pin is detected by a touch sensor, and the first contact position storage means for storing the contact position, the contact position stored in the reference tool contact position storage means, and the first contact position storage means are stored. A first relative distance calculating means for calculating a relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor based on the contact position, and a calculation by the first relative distance calculating means. A touch sensor distance calculating means for calculating a distance from the tool axis to the tip of the touch sensor from a measured relative distance and a diameter of the reference rotating tool, and a tool contact position for storing a contact position of the rotating tool to the detection pin After contact with the detection pin by the rotating tool with the storage means, the second contact position storage means for detecting the contact surface of the detection pin with a touch sensor and storing the contact position, and the tool contact position storage means. Second relative distance calculation means for calculating a relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the second contact position storage means and the second contact position storage means; The rotation based on the relative distance calculated by the relative distance calculation means and the distance from the tool axis to the tip of the touch sensor calculated by the touch sensor distance calculation means. A rotating tool diameter calculating means for calculating the tool diameter; and a tool correcting means for cutting the truing tool by a predetermined amount into the end face of the rotating tool based on the diameter of the rotating tool calculated by the rotating tool diameter calculating means. That is.

  Further, the structural feature of the invention according to claim 5 is that a reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter, and an X-axis detection that is fixed to the table and extends along the X-axis and the Z-axis. A pin and a Z-axis detection pin; a side-distance storage means for storing a distance from the center of the rotary tool to a side of the reference rotary tool or the rotary tool; and contact with the X-axis detection pin by an outer peripheral surface of the reference rotary tool X-axis contact position storage means for storing a position; Z-axis contact position storage means for storing a contact position of the reference rotary tool or the side surface of the rotary tool to the Z-axis detection pin; a diameter of the reference tool; Based on the distance from the center of the rotary tool stored in the distance storage means to the side surface of the reference rotary tool or the rotary tool, and the cutting position to the X-axis detection pin and the Z-axis detection pin, the center of the rotary tool is determined. Correction coordinates Coordinate correction means for calculating, and after contact with the X axis detection pin by the reference rotary tool, a first contact position storage means for detecting contact with the end surface of the X axis detection pin with a touch sensor and storing the contact position; Based on the X-axis contact position stored in the X-axis contact position storage means and the contact position stored in the first contact position storage means, the relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor is calculated. First relative distance calculating means for calculating, and touch sensor distance calculating means for calculating the distance from the tool center to the tip of the touch sensor from the relative distance calculated by the first relative distance calculating means and the diameter of the reference rotating tool. A cutting execution means for making contact with the X-axis detection pin based on a correction coordinate of the center of the rotary tool by the coordinate correction means, and a contact with the X-axis detection pin by the cutting execution means Tool contact position storage means for storing the position, and second contact position storage means for detecting the contact of the end surface of the X axis detection pin with a touch sensor after the contact with the X axis detection pin by the rotary tool and storing the contact position And calculating the relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the tool contact position storage means and the contact position stored in the second contact position storage means. A spherical surface of the rotary tool based on a second relative distance calculation means, a relative distance calculated by the second relative distance calculation means, and a distance from the tool center to the tip of the touch sensor calculated by the touch sensor distance calculation means. A rotating tool spherical diameter calculating means for calculating a diameter; a tool center of the rotating tool calculated by the coordinate correcting means; and a spherical diameter calculated by the rotating tool spherical diameter calculating means. And spherical truing means for performing truing of the rotary tool on the basis thereof.

  According to the present invention, when the rotary tool is worn by machining, the outer peripheral surface and / or the tool side surface before the rotary tool is worn are machined from the reference position determined by the reference tool. The amount of movement of the worn rotating tool until the current outer peripheral surface and / or tool side surface contacts or cuts the detection pin is obtained. Next, the difference (distance) between the position where the current outer peripheral surface and / or the tool side surface of the rotary tool is in contact with or cut into the detection pin and the reference position is obtained, and the distance between the two positions and the movement amount are calculated. Since the deviation becomes the amount of wear of the rotary tool, by correcting the diameter or tool width before the rotary tool is worn by this amount of wear, the current diameter of the rotary tool and / or the movement of the rotary axis due to thermal displacement are eliminated. Alternatively, the tool width can be determined.

  According to the present invention, since the reference tool is arranged coaxially with the rotary tool by configuring as in claim 2, even if the rotation axis of the rotary tool moves due to thermal displacement, the reference tool moves similarly. To do. Therefore, if the diameter of the reference tool is known, the distance from the rotation axis to the tip of the touch sensor can be obtained, and the diameter of the rotary tool can be accurately determined based on the distance from the rotation axis to the tip of the touch sensor. Thus, the positional relationship between the tip position of the rotary tool and the workpiece can be accurately corrected.

  Further, according to the third aspect of the present invention, even if the rotation axis of the rotary tool moves due to thermal displacement and the tool center moves, the reference tool moves in the same manner. For this reason, the movement amount by the thermal displacement of a tool center is detectable by detecting the position change of the outer peripheral surface and side surface (or side surface of a rotary tool) of a reference | standard tool. By correcting the position of the tool center by the amount of movement of this thermal displacement, the positional relationship between the rotary tool and the workpiece can be accurately grasped.

  Further, since the reference tool is arranged coaxially with the rotary tool by configuring as in the fourth aspect, even if the rotation axis of the rotary tool moves due to thermal displacement, the reference tool moves in the same way. Therefore, if the diameter of the reference tool is known, the distance from the rotation axis to the tip of the touch sensor can be obtained, and the diameter of the rotary tool can be accurately determined based on the distance from the rotation axis to the tip of the touch sensor. Since the diameter of the rotating tool can be obtained accurately, the correction amount at the time of truing can be accurately managed, and therefore the optimum truing can be realized without excessively truing the rotating tool.

  In addition, since the rotation axis of the rotary tool moves due to thermal displacement and the tool center moves, the reference tool moves in the same manner. For this reason, the movement amount by the thermal displacement of a tool center is detectable by detecting the position change of the outer peripheral surface and side surface (or side surface of a rotary tool) of a reference | standard tool. By correcting the position of the tool center by the amount of movement of this thermal displacement, the distance from the rotation axis to the tip of the touch sensor can be obtained if the diameter of the reference tool is known. The diameter of the rotary tool can be accurately determined based on the distance to the tip, and if the accurate diameter of the rotary tool and the position of the tool center are determined, the spherical blade surface of the rotary tool can be accurately trued.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. FIG. 1 is a plan view of a cylindrical grinding machine 10 that embodies a grinding apparatus according to an embodiment of the present invention. In FIG. 1, a table 14 is supported on a bed 12 so as to be movable in the Z-axis direction. A headstock 16 and a tailstock 18 are disposed on the table 14 so as to face each other. A spindle 17 is supported on the spindle stock 16 so as to be rotatable about a rotation axis Q parallel to the Z axis. It is rotationally driven by a motor. A chuck 17 a that holds one end of the workpiece W is provided at one end of the main shaft 17. A center 18 a that supports the other end of the workpiece W as a center is supported on the tailstock 18 so as to be rotatable coaxially with the rotation axis Q. As a result, the workpiece W is rotationally driven with the chuck 17a and the center 18a supporting both ends of the workpiece W coaxially with the rotation axis Q.

  The table 14 is provided with a contact detection device 30 for detecting the position of the grinding wheel 22 described later and a truing device 40 for sharpening the grinding wheel 22. In the contact detection device 30, a detection pin 34 that faces the outer peripheral side of the grinding wheel 22 protrudes from the detection pin head 32 in the X direction. The detection pin head 32 is supported on the table 14 side via a vibration detector (hereinafter referred to as an AE sensor) 36 that detects a contact signal between the detection pin 34 and the grinding wheel 22. On the other hand, as shown in FIG. 2A, the truing device 40 is configured such that a truing tool 44 is rotated on a truing shaft 42 when the truing shaft 42 is rotated by a built-in motor (not shown). Yes.

  On the bed 12, a grindstone table 20 as a tool table is guided and supported in the X-axis direction orthogonal to the moving direction of the table 14, and the grindstone wheel 22 is parallel to the moving direction of the table 14 on the grindstone table 20. It is supported rotatably around O. The grinding wheel 22 includes a disk-shaped grinding wheel (rotary tool) 22a and a reference grinding wheel (reference tool) 22b attached to the side surface of the grinding wheel 22a. The grinding wheel 22a grinds the workpiece W, the reference grindstone 22b is used to measure the diameter of the grinding wheel 22a, and both the grindstones 22a and 22b are integrally coupled and driven to rotate by the grindstone drive motor 24. It has become. A touch sensor 50 is disposed on the table 14 side of the grindstone table 20. As shown in FIG. 2A, the touch sensor 50 has a measurement head 54 for detecting the position in contact with the tip of the detection pin 34, and a feeler 52 for supporting the measurement head 54. In order to avoid contact with other members, they are retracted to a position indicated by a dotted line in FIG. The touch sensor 50 is configured to send an end face measurement signal to the numerical controller 60 side when detecting contact with the detection pin 34.

  Next, the configuration of the numerical controller 60 that controls the cylindrical grinding machine 10 will be described. The numerical controller 60 mainly includes a central controller 62 that manages the entire apparatus, a memory 64 that stores various control values and programs, and interfaces 66 and 68. The memory 64 stores a grinding program, a grindstone correction program, a grindstone diameter correction program, grindstone diameter data, and a distance C from the rotation axis Q to the measuring head 52. An input device 70 is connected to the numerical control device 60 through an interface 66, and various data are input by the input device 70. The input device 70 includes a keyboard for inputting data and the like, and a display device such as a CRT for displaying data. In addition, a contact signal from the contact detection device 30 is input to the numerical control device 60 via an amplifier 72. The amplifier 72 is configured to output an on / off signal to the numerical control device 60 side in response to a detection signal from the contact detection device 30.

  The numerical control device 60 is driven via a first motor drive circuit 80 to a first servo motor 82 for sending the grinding wheel base 20 in the X-axis direction orthogonal to the moving direction of the table 14 by a ball screw (not shown). Give a signal. The first encoder 84 attached to the first servo motor 82 sends the rotational position of the first servo motor 82, that is, the position of the grindstone table 20 to the first motor drive circuit 80 and the numerical controller 60 side. It is configured.

  The numerical controller 60 gives a drive signal via a second motor drive circuit 90 to a second servo motor 92 for feeding the table 14 in the horizontal direction by a ball screw (not shown). The second encoder 94 attached to the second servo motor 92 is configured to send the position of the table 14 to the second motor drive circuit 90 and the numerical controller 60.

  Here, the coordinate system of the cylindrical grinding machine 10 will be described. There are two types of coordinate systems: a machine coordinate system and a workpiece coordinate system. A point unique to the machine is the origin, the basic coordinate system is called the machine coordinate system, and a coordinate system that can be arbitrarily set (position stored) by the user with a certain point on the workpiece as the program origin is called the work coordinate system. Normally, the cylindrical grinding machine 10 is controlled by this work coordinate system. In the workpiece coordinate system for the X axis, the center of the workpiece W (rotation axis O) is the program origin, and the current position of the grinding wheel base is “0” when the center of the workpiece W and the tip of the grinding wheel 22a coincide with each other. It is said that. The grindstone table 20 is set as a retreat end Xend where the tip of the grindstone has retreated by a predetermined amount from the center of the workpiece W, and the movement command of the grindstone table 20 at the time of machining is commanded by the advance amount from the retreat end Xend. The For this reason, when the tip position of the grinding wheel 22a changes due to wear and truing due to processing, it is necessary to advance the grinding wheel base 20 to correct the backward end Xend, and the grinding machine 10 is always capable of accurate grinding wheel 22a. Remember the diameter. When the grinding wheel 22 is replaced with a new one, a grinding wheel diameter correction process is performed, and after machining is performed based on accurate grinding wheel diameter data, machining is started. Then, when a predetermined number of workpieces W are processed and it becomes necessary to correct the grindstone surface of the grinding wheel 22a, truing is performed, and the truing and workpiece machining are repeated. Further, in the cylindrical grinding machine 10 of the present embodiment, as will be described later, the grinding wheel diameter correction processing is performed in the truing interval, and the grinding wheel diameter data is updated to always proceed the processing based on accurate grinding wheel diameter data. The operation of the cylindrical grinding machine 10 will be described with reference to the explanatory diagram of FIG. 2 and the flowcharts of FIGS.

  The numerical controller 60 first determines whether the grinding wheel 22 has been replaced (S100 shown in FIG. 3). When the grinding wheel 22 is replaced (S100 is Yes), the temporary grinding wheel diameter is stored as the current grinding wheel diameter RO, and the grinding wheel 22 when the grinding wheel base is at the retracted end based on the grinding wheel diameter R0 is stored. The tip position Xend is initialized. (S101) Thereafter, the grinding wheel 22a is shaken (S102). Here, the runout refers to a portion that is not a perfect circle around the grindstone axis O on the outer peripheral surface of the grindstone, and when the grindstone wheel 22 is attached to the grindstone shaft (not shown), a runout of several hundred μm occurs. Has occurred. For this reason, in the same manner as the operation at the time of truing described later, contact is made in several tens of times with the truing tool 44, and the surface of the grindstone is peeled off to remove the shake.

Then, the numerical controller 60 starts truing (S103). This truing is performed continuously with the above-described run-out cycle. The truing process will be described in detail with reference to the flowchart of FIG. 6 showing the subroutine of the process and FIG. 2 showing the operation at this time.
When the grindstone is replaced, the memory 64 of the numerical controller 60 shown in FIG. 1 stores the diameter G of the reference grindstone 22b and the temporary diameter R0 of the grindstone 22a. In this state, the accurate length C of the measuring head 52 of the touch sensor 50 is measured. By controlling the second servo motor 92 and moving the table 14 horizontally, the reference grindstone 22b and the detection pin 34 are brought into a position facing each other, and then the first servo motor 82 is controlled to place the grindstone table 20 on the table. 14 side, and the grindstone base 20 is moved until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 2 (A) (S400). This contact feed is continued until a contact signal is detected (S401 is No). When the contact between the detection pin 34 and the outer periphery of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (S401 is Yes), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xa of the tip position of the grindstone 22a from the center of the workpiece W are stored (S402). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 2B, the touch sensor 50 is turned to the measurement position, and then the second servo motor 92 is controlled to move the table 14 horizontally, whereby the feeler 54 and the detection pin 34 are moved. 2, the first servo motor 82 is controlled to send the grinding wheel base 20 to the table 14 side, and the grinding wheel base 20 is touched until the feeler 54 contacts the detection pin 34 as shown in FIG. Is moved (S403). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S404), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xb of the tip position of the grinding wheel from the center of W are stored (S405). Then, the grindstone platform 20 is retracted to the retracted end Xend.

Then, the exact length C of the feeler 54 is calculated from the contact position coordinate Xa of the reference grindstone 22b and the contact position coordinate Xb of the touch sensor 50 by the following formula, and the distance C from the rotation axis Q to the measuring head 52 is stored in the memory 64. To remember. (S406).
C = (Xa−Xb) + G (1)
Next, as shown in FIG. 2C, the grinding wheel base 20 is moved until the grinding wheel 22a contacts the detection pin 34 (S407). This contact feed is continued until a contact signal is detected (No in S408). When the contact between the detection pin 34 and the outer periphery of the grinding wheel is detected by the AE sensor 36 and the contact signal is input through the amplifier (S408 is Yes), the movement of the table 14 is stopped and The contact position coordinates of the grinding wheel, that is, the coordinates Xc of the tip position of the grinding wheel from the center of the workpiece W are stored (S409). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 2D, after the touch sensor 50 is turned to the measurement position, the second servo motor 92 is controlled to move the table 14 horizontally, whereby the feeler 54 and the detection pin 34 are moved. 2, the first servo motor 82 is controlled to feed the grinding wheel base 20 to the table 14 side, and the grinding wheel base 20 is touched until the feeler 54 contacts the detection pin 34 as shown in FIG. Is moved (S410). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S411), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xd of the tip position of the grinding wheel 22a from the center of W are stored (S412). Then, the grindstone platform 20 is retracted to the retracted end Xend.

Then, the actual grinding wheel diameter R1 is obtained by the following equation (S413).
R1 = (Xc−Xd) + C (2)
In order to measure the amount of wear that occurred during processing, the diameter R1 of the grinding wheel measured this time is calculated from the diameter R0 (temporary diameter in this case) of the grinding wheel that was previously measured and stored in the memory 64. By subtracting, a change amount ΔR (= R0−R1) of the grindstone diameter is calculated, and this value ΔR is stored (S414), and the diameter R0 of the grinding wheel 22a when the measurement is performed previously is obtained by this calculation. The grinding wheel 22a is replaced with the diameter R1 (S415). Then, the position (= Xend + ΔR) where the wheel head 20 is moved forward by the change amount ΔR is updated to the retreat end Xend of the new wheel head (S416). Here, since the grinding wheel is replaced immediately, the change ΔR is zero if there is no thermal displacement.
Thereafter, the table 14 is moved horizontally so that the grinding wheel 22a and the truing tool 44 are opposed to each other, and then the first servo motor 82 is controlled to move the wheel base 20 from the retracted end Xend to the table 14 side. A fixed amount is fed, and the grindstone surface is positioned at the grindstone correction start position facing the correction grinding surface of the truing tool 44 (S417). Then, the grinding wheel base 20 is moved forward by the corrected cutting amount T1 (S418), and the table 14 is moved horizontally, whereby the grinding wheel surface of the grinding wheel 22b is trued with the corrected grinding surface 44a (S419). The correction cutting amount T1 may be divided into a plurality, and the correction cutting amount of the table 14 and the correction feed of the grindstone table 20 may be performed a plurality of times. When the correction of the grindstone surface G1 is finished, the grindstone base 20 is retracted to the retracted end Xend.
Thereafter, the numerical controller 60 updates the back end Xend of the grinding wheel base (= Xend + T1) based on the wheel diameter reduction amount T1 (S420), and ends the truing process on the grinding wheel surface.

  The description will be continued again with reference to the flowchart of FIG. 5 showing the main operation. When the truing process in step 103 is completed, the numerical controller 60 resets the variable K indicating the number of machining after truing (S104), and resets the variable D indicating the number of machining after the grinding wheel width correction (S105). ).

  Thereafter, the workpiece W is carried in and held between the head stock 16 and the tailstock 18 on the table 14 shown in FIG. 1 (S106 shown in FIG. 4). Then, it is determined whether to perform truing based on whether or not the variable K indicating the machining number after truing exceeds a predetermined number K1 (here, 100) (S107). Here, since processing is to be started, the determination in step 107 is No, and the process proceeds to step 111.

  In step 111, the workpiece W is machined based on the data of the backward end Xend updated and stored in the memory 64. Thereafter, 1 is added to the variable K indicating the number of processed pieces after truing (S112). Further, 1 is added to the variable D indicating the number of machining after the grinding wheel diameter correction (S113).

  Subsequently, the numerical controller 60 determines whether or not to correct the grinding wheel diameter (S114 shown in FIG. 7). That is, it is determined whether or not the machining number D after the grinding wheel diameter correction has exceeded a preset predetermined number D1 (here, 20), and if it exceeds the predetermined number D1 (Yes in S114). ) In the truing interval (from the truing to the next truing), the grindstone diameter correction described later is performed (S115). Here, since the machining of the first workpiece W has been performed (No in S114), the process proceeds to step 117, where the workpiece W that has been machined is unloaded and it is determined whether machining has been completed for all the workpieces W ( S118). Here, since the processing has not been completed (No in S118), the process returns to step 100 shown in FIG.

In Step 100, it is determined whether the grinding wheel 22 has been replaced. Here, the determination in Step 100 is No, the workpiece W is loaded (S108 shown in FIG. 4), and the next workpiece W is processed. To start.
Then, the machining of the workpiece W is repeated, and when the machining number D exceeds a predetermined number D1 (20), that is, step 114 becomes Yes at the 21st machining, and the grindstone diameter correcting process (S115) is performed. .

Here, the grindstone diameter correcting process in step 115 will be described with reference to FIG. 7 showing a subroutine of the process.
This grindstone diameter correcting process is the same as the process from step 400 to step 416 of the truing process shown in FIG. In the memory 64 of the numerical controller 60 shown in FIG. 1, the diameter G of the reference grindstone 22b and the diameter R0 of the grinding wheel measured before are stored. In this state, the accurate length C of the measuring head 52 of the touch sensor 50 is measured. By controlling the second servo motor 92 and moving the table 14 horizontally, the reference grindstone 22b and the detection pin 34 are brought into a position facing each other, and then the first servo motor 82 is controlled to place the grindstone table 20 on the table. 14 side, and the grindstone base 20 is moved until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 2 (A) (S450). This contact feed is continued until a contact signal is detected (No in S451). When the contact between the detection pin 34 and the outer periphery of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (Yes in S451), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xa of the tip position of the grinding grindstone 22a from the center of the workpiece W are stored (S452). Then, the grindstone platform 20 is retracted to the retracted end Xend.

Next, as shown in FIG. 2B, after the touch sensor 50 is turned to the measurement position, the second servo motor 92 is controlled to move the table 14 horizontally, whereby the measurement head 54 and the detection pin are moved. 34, the first servo motor 82 is controlled to feed the grindstone table 20 to the table 14 side, and the grindstone is moved until the measuring head 54 contacts the detection pin 34 as shown in FIG. The table 20 is moved (S453). When contact between the detection pin 34 and the measurement head 54 is detected and a contact signal is input (Yes in S454), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, The coordinates Xb of the tip position of the grinding wheel 22a from the center of the workpiece W are stored (S455). Then, the grindstone platform 20 is retracted to the retracted end Xend.
Then, the distance C from the rotation axis Q to the measurement head 52 is calculated from the contact position coordinate Xa of the reference grindstone 22b and the contact position coordinate Xb of the touch sensor 50 by the equation (1), and the distance from the rotation axis Q to the measurement head 52 is calculated. The distance C is stored in the memory 64 (S456).

  Next, as shown in FIG. 2C, the grinding wheel base 20 is moved until the grinding wheel 22b contacts the detection pin 34 (S457). This contact feed is continued until a contact signal is detected (No in S458). When the contact between the detection pin 34 and the outer periphery of the grinding wheel 22a is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (S458 is Yes), the movement of the table 14 is stopped. The contact position coordinates of the grinding wheel 22a, that is, the coordinates Xc of the tip position of the grinding wheel 22a from the center of the workpiece W are stored (S459). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 2D, after the touch sensor 50 is turned to the measurement position, the second servo motor 92 is controlled to move the table 14 horizontally, whereby the measurement head 54 and the detection pin are moved. 34, the first servo motor 82 is controlled to feed the grindstone table 20 to the table 14 side, and the grindstone table is moved until the feeler 54 contacts the detection pin 34 as shown in FIG. 20 is moved (S460). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S461), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xd of the tip position of the grinding wheel 22a from the center of W are stored (S462). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Thereafter, the diameter R1 of the actual grinding wheel is obtained by the equation (2) (S463), and the grinding wheel 22a when the measurement is performed before being stored in the memory 64 in order to measure the wear amount generated during the processing. The grinding wheel diameter change amount ΔR (= R0−R1) is calculated by subtracting the grinding wheel diameter R1 measured this time from the diameter R0, and this value is stored (S464). The diameter R0 of the grinding wheel 22a is replaced with the diameter R1 of the grinding wheel 22a obtained by this calculation. (S465). Then, the position (= Xend + ΔR) where the wheel head is advanced by this change amount ΔR is updated to the backward end Xend of the new wheel head (S466).

  Upon completion of the grinding wheel diameter correction process, the machining number D is cleared (S116 shown in FIG. 5), the process proceeds to step 117, and the workpiece W that has been machined is carried out. Thereafter, the machining is continued, and the grinding wheel diameter correction process is repeated every 20 machining cycles (that is, the 41st, 61st, and 81st).

  When the number of workpieces C processed becomes the 101st and exceeds the predetermined number K1 (100) set in advance, the determination of K> K1 in step 107 shown in FIG. 6 becomes Yes, and the truing process is started. (S108) The truing of the grinding wheel 22a is performed by truing in the same manner as with reference to FIGS. Upon completion of the truing process (S108), the value of the variable K indicating the number of workpieces after truing is reset (S109), and the grinding wheel diameter correction is performed in order to avoid performing the grinding wheel diameter correction subsequent to truing. The value of the variable D indicating the number of subsequent machining is reset (S110). Here, after the end of the truing process (S108), the grindstone diameter R0 is updated to R1.

  Thereafter, the loaded workpiece W (101st workpiece) is processed (S111), and the workpiece W is unloaded through the processing from step 112 to step 114 (S117).

  The numerical controller 60 performs the above-described grinding wheel diameter correction processing on the 121st, 141st, 161st, and 181st lines after the end of truing at the time of processing the 101st work until the next truing at the time of machining the 201st work. (S115) is performed. This can reduce errors in cases where there is a large amount of change due to grinding wheel wear and thermal displacement during the truing interval (for example, when the number of workpieces W is large), resulting in defective products. To prevent.

  In this embodiment, the grindstone diameter correction process is performed several times during the truing interval in the machining cycle. For this reason, when it is determined that the grinding wheel wear amount and the thermal displacement amount are small during the truing interval, it is possible to omit the grinding wheel diameter correction processing in the truing interval. This can be realized by setting the variable D1 and the variable K1 equal.

  As described above, by providing the reference grindstone 22b coaxially with the grinding grindstone 22a, even if the rotation axis Q moves due to thermal displacement, the grindstone 22a and the reference grindstone 22b move by the equivalent thermal displacement. It will be. Therefore, the current grindstone diameter can be accurately obtained by correcting the distance C from the rotation axis Q to the measuring head 52 based on the diameter G of the reference grindstone 22b. Therefore, by correcting the coordinate system based on the current grindstone diameter, it is possible to improve the grinding accuracy and to perform the truing process with high accuracy.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the description of the second embodiment, illustration and description of members similar to those of the first embodiment are omitted. In the second embodiment, as shown in FIG. 8A, the grinding surface of the grinding wheel is a spherical grinding wheel 23 formed into a spherical surface centered on a point P set on the axis O. Further, in order to prevent interference between the table and the grindstone table due to the approach of the spherical grindstone 23 and the workpiece W during grinding, the axis O is installed with an inclination of an angle θ.

  Thus, when grinding using the spherical grindstone 23, it is necessary to accurately obtain the position of the center point P of the spherical grindstone 23 and to perform truing and coordinate setting based on the center point P. Therefore, in the cylindrical grinder 10 in the second embodiment, the center point of the spherical grindstone is obtained by measuring the thermal displacement in the direction in which the grindstone axis O extends and the direction orthogonal to the grindstone axis O in addition to the grindstone diameter. In the cylindrical grinding machine 10 according to the second embodiment, as shown in FIG. 8A, in order to measure the thermal displacement in the direction in which the grinding wheel axis O extends, the detection pin 34 that extends in the X-axis direction and the Z-axis direction extend. And a detection pin 35.

  In the second embodiment, the coordinate in the X-axis direction is “0” when the center of the workpiece W and the workpiece-side tip of the grinding wheel coincide with each other, as in the first embodiment. The value is set so as to increase as the grindstone head moves backward. The coordinate in the Z-axis direction is set such that the left or right moving end of the table is set to “0”, and the left moving end is set to “0” here.

  Further, in the memory 64, as initial setting values at the time of exchanging the grindstone, the diameter G of the reference grindstone 22b, the provisional diameter R0 of the spherical grindstone, the coordinates (X0, Z0) of the provisional center position P of the spherical grindstone, and the reference grindstone 22b The distance H from the side surface to the center point P is stored. Further, the tip position Xend of the spherical grinding wheel at the retreating end of the grinding wheel base calculated in advance or experimentally based on these grinding wheel data, and the initial contact position Xα0 of the grinding wheel tip when the reference grinding wheel 22b contacts the detection pin 34. In addition, an initial contact position Zα0 where the side surface of the reference grindstone 22b contacts the detection pin 35 is stored.

  The operation of the grinding machine in the second embodiment will be described below. The main operation is substantially the same as the main operation in the first embodiment shown in FIGS. 3 to 5, and the initial contact positions Xα0 and Zα0 in step 102 are set to Xα and Zα as parameter values indicating the contact positions. The only difference is.

  Accordingly, the description of the main operation is omitted, and only the operations of truing and grindstone diameter correction shown in steps 103, 108, and 115 of FIGS. 3 to 5 will be described.

  The truing operation shown in steps 103 and 108 of FIGS. 3 to 5 will be described with reference to FIGS. First, after the initial contact position Xα0 at the tip of the grindstone and the initial contact position Zα0 at which the side surface of the reference grindstone 22b contacts the detection pin 35 are set to the contact positions Xα and Zα (S500), the center position of the actual spherical grindstone is obtained. . The actual center of the spherical grindstone 23 is obtained by the procedure from step 501 to step 509 shown in FIG. The second servo motor 92 is controlled to move the table 14 horizontally, so that the cylindrical surface of the reference grindstone 22b and the detection pin 34 face each other, and then the first servo motor 82 is controlled to grindstone table. 20 is sent to the table 14 side, and the grindstone base 20 is moved until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 8A (S501). This contact feed is continued until a contact signal is detected (No in S502). When the contact between the detection pin 34 and the cylindrical surface of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (Yes in S502), the movement of the table 14 is stopped. At the same time, the contact position coordinates of the reference grindstone 22b, that is, the coordinates Xβ of the tip position of the spherical grindstone 23 from the center of the workpiece W are stored (S503). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, after setting the side surface of the reference grindstone 22b and the detection pin 35 to face each other, the first servo motor 82 is controlled to send the table 14 to the grindstone table 20 side, and as shown in FIG. The table 14 is moved until the side surface of 22b contacts the detection pin 35 (S504). This contact feed is continued until a contact signal is detected (No in S505). When the contact between the detection pin 35 and the side surface of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input via the amplifier 72 (Yes in S505), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xβ of the position from the moving end of the table 14 are stored (S506). Then, the grindstone table 20 moves backward to the backward end Xend and returns the table 14 to the left moving end.

Then, an error ΔX in the X direction and an error in the Z direction are obtained from the currently set contact positions Xα and Zα and the current contact positions Xβ and Zβ measured in steps 503 and 506 by the following equations (S507).
ΔX = Xα−Xβ (3a)
ΔZ = Zα−Zβ (3b)
The errors ΔX and ΔZ indicate the shift of the grinding wheel axis of the grinding wheel base 20 due to thermal displacement. In step 508, the contact positions Xα and Zα are replaced with the current contact positions Xβ and Zβ in preparation for the next measurement.

Next, in step 509, the provisional (previous) center position P0 (X0, Z0) of the set spherical grindstone 23 is corrected to the actual center by the following equation.
X0 = X0−ΔX (4a)
Z0 = Z0−ΔZ (4b)
Further, since the shift of the grinding wheel axis of the grinding wheel base due to thermal displacement also affects the backward end Xend, in step 510, the backward end Xend is updated by the following equation.
Xend = Xend−ΔX (5)
Following the renewal of the shift of the backward end Xend due to the thermal displacement in step 510, the measurement of the grindstone diameter is achieved by steps 511 to 524 shown in FIG.

First, an accurate length Cx in the grinding wheel diameter direction (W direction shown in FIG. 9B) from the rotation axis O of the grinding wheel to the measurement head 52 of the touch sensor 50 is measured.
By controlling the second servo motor 92 and moving the table 14 horizontally, the reference grindstone 22b and the detection pin 34 are brought into a position facing each other, and then the first servo motor 82 is controlled to place the grindstone table 20 on the table. 14 side, and the grindstone base 20 is moved until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 9A (S511). This contact feed is continued until a contact signal is detected (No in S512). When the contact between the detection pin 34 and the outer periphery of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input via the amplifier 72 (S512 is Yes), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xa of the tip position of the spherical grindstone 23 from the center of the workpiece W are stored (S513). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 9B, after the touch sensor 50 is turned to the measurement position, the feeler 54 and the detection pin are moved by controlling the second servo motor 92 and moving the table 14 horizontally. After the opposing position is reached, the first servo motor 82 is controlled to feed the grinding wheel base 20 to the table 14 side, and the grinding wheel base 20 is moved until the feeler 54 contacts the detection pin 34 as shown in FIG. 9B. (S514). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S515), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xb of the tip position of the spherical grindstone 23 from the center of W are stored (S516). Then, the grindstone platform 20 is retracted to the retracted end Xend.

Then, the exact length Cx of the feeler 54 is calculated from the contact position coordinate Xa of the reference grindstone 22b and the contact position coordinate Xb of the touch sensor 50 by the following formula, and the distance Cx from the rotation axis Q to the measuring head 52 is stored in the memory 64. To remember. (S517).
Cx = (Xa / Cosθ) − (Xb / Cosθ) + G (6)
Next, as shown in FIG. 10 (A), the table 14 and the grindstone base 20 are simultaneously controlled in two axes while giving a fine notch in the X-axis direction, and the spherical grindstone 23 is detected in the direction parallel to the grindstone axis O. The grindstone platform 20 is moved until it comes into contact with (S518). This contact feed is continued until a contact signal is detected (No in S519). When the contact between the detection pin 34 and the outer periphery of the spherical grindstone 23 is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (Yes in S519), the grindstone table 20 and the table 14 are moved. And the contact position coordinates of the spherical grindstone 23, that is, the coordinates Xc of the tip position of the spherical grindstone 23 from the center of the workpiece W are stored (S520). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 10B, after turning the touch sensor 50 to the measurement position, the feeler 54 and the detection pin 34 are controlled by controlling the second servo motor 92 and moving the table 14 horizontally. And the first servo motor 82 is controlled to feed the wheel head 20 to the table 14 side, and the wheel head 20 is moved until the feeler 54 contacts the detection pin 34 as shown in FIG. Is moved (S521). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S522), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xd of the tip position of the spherical grindstone 23 from the center of W are stored (S523). Then, the grindstone platform 20 is retracted to the retracted end Xend.

And the diameter R1 of the actual spherical grindstone 23 is calculated | required by following Formula (S524).
R1 = (Xc / Cosθ) − (Xd / Cosθ) + Cx (7)
In order to measure the amount of wear generated during machining, the diameter of the spherical grindstone 23 measured this time from the diameter R0 (temporary diameter here) of the spherical grindstone 23 measured previously before being stored in the memory 64. By subtracting R1, the change amount ΔR (= R0−R1) of the grindstone diameter is calculated (S525), and this value ΔR is stored, and the diameter R0 of the spherical grindstone 23 when previously measured is calculated this time. This is replaced with the diameter R1 of the spherical grindstone 23 obtained in step S526. Then, the X-direction component ΔRx of the change amount ΔR is obtained by the following equation (S527).

          ΔRX = ΔR · Cosθ (8)

Then, based on the X-direction component ΔRx of the diameter change amount ΔR of the spherical grindstone 23, the position (= Xend−ΔRx) where the grindstone head is advanced is updated to the retreat end Xend of the new grindstone base (S528). Note that the amount of change ΔR is zero and the X-direction component ΔRx is also zero immediately after the wheel replacement.
After that, the table 14 is moved horizontally based on the coordinates (X0, Z0) of the center position P of the spherical grindstone 23, so that the spherical grindstone 23 and the truing tool 44 face each other, and then the first servo motor. 82 is controlled to feed the grindstone table 20 by a predetermined amount from the retracted end Xend to the table 14 side, and the grindstone surface of the spherical grindstone is positioned at the grindstone correction start position facing the truing tool 44 (S529). Then, the grinding wheel base 20 is moved forward by the correction cutting amount T1 (S530), the table 14 and the grinding wheel base 20 are controlled in two axes, and the truing tool 44 is centered on the coordinates (X0, Z0) of the center position P of the spherical grinding wheel 23. Control is made to move around the circumference of the diameter (R1-T1) (S531). As a result, the grinding surface of the spherical grindstone 23 is trued into a highly accurate spherical surface that eliminates the effects of thermal displacement and grinding wheel wear, and when the grindstone surface G1 is corrected, the grindstone base 20 moves back to the retreat end Xend.

  After that, the numerical controller 60 updates the back end Xend of the grinding wheel base (= Xend−T1) based on the grinding wheel diameter reduction amount T1 (S532), and ends the truing process on the grinding wheel surface.

The grindstone diameter correcting process in step 115 will be described with reference to FIGS. 13 and 14 showing a subroutine of the process.
This grindstone diameter correcting process is the same as the process from step 500 to step 528 of the truing process shown in FIGS. That is, after the initial contact position Xα0 of the grindstone tip and the initial contact position Zα0 where the side surface of the reference grindstone 22b contacts the detection pin 35 are set to the contact positions Xα and Zα (S550), the center position of the actual spherical grindstone 23 is set. Ask. The actual center of the spherical grindstone 23 is obtained by the procedure from step 551 to step 559 shown in FIG. The second servo motor 92 is controlled to move the table 14 horizontally, so that the cylindrical surface of the reference grindstone 22b and the detection pin are opposed to each other, and then the first servo motor 82 is controlled to move the grindstone table 20. It sends to the table 14 side, and moves the grindstone base 20 until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 8A (S551). This contact feed is continued until a contact signal is detected (No in S552). When the contact between the detection pin 34 and the cylindrical surface of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input via the amplifier 72 (S552 is Yes), the movement of the table 14 is stopped. At the same time, the contact position coordinates of the reference grindstone 22b, that is, the coordinates Xβ of the tip position of the spherical grindstone from the center of the workpiece W are stored (S553). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, after setting the cylindrical surface of the reference grindstone 22b and the detection pin to face each other, the first servo motor 82 is controlled to feed the table 14 to the grindstone table 20, and as shown in FIG. 8B, the reference grindstone 22b. The table 14 is moved until the side surface thereof contacts the detection pin 34 (S554). This contact feed is continued until a contact signal is detected (S555 is No). When the contact between the detection pin 34 and the side surface of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (S555 is Yes), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xβ of the position from the table moving end are stored (S556). Then, the grindstone table 20 moves backward to the backward end Xend and returns the table 14 to the left moving end.

  Then, from the currently set contact positions Xα and Zα and the current contact positions Xβ and Zβ measured in step 553 and step 556, the errors in the X direction ΔX and the errors in the Z direction are calculated according to equations (3a) and (3b). Obtain (S557).

  The errors ΔX and ΔZ indicate the shift of the grindstone axis of the grindstone table due to thermal displacement. In step 558, the contact positions Xα and Zα are replaced with the current contact positions Xβ and Zβ in preparation for the next measurement.

Next, in step 559, the provisional (previous) center position P0 (X0, Z0) of the set spherical grindstone 23 is corrected to the actual center by the equations (4a) and (4b).
Furthermore, since the deviation of the grinding wheel axis of the grinding wheel base due to the thermal displacement also affects the backward end Xend, in step 560, the backward end Xend is updated by equation (5).
Following the renewal of the shift of the backward end Xend due to the thermal displacement in step 560, the measurement of the grindstone diameter is achieved by steps 561 to 574.
First, an accurate length Cx in the grinding wheel diameter direction (W direction shown in FIG. 9B) from the rotation axis O of the grinding wheel to the measurement head 52 of the touch sensor 50 is measured.

  By controlling the second servo motor 92 and moving the table 14 horizontally, the reference grindstone 22b and the detection pin 34 are brought into a position facing each other, and then the first servo motor 82 is controlled to place the grindstone table 20 on the table. 14 side and moves the grindstone base 20 until the reference grindstone 22b contacts the detection pin 34 as shown in FIG. 9A (S561). This contact feed is continued until a contact signal is detected (No in S562). When the contact between the detection pin 34 and the outer periphery of the reference grindstone 22b is detected by the AE sensor 36 and the contact signal is input through the amplifier 72 (S562 is Yes), the movement of the table 14 is stopped. The contact position coordinates of the reference grindstone 22b, that is, the coordinates Xa of the tip position of the spherical grindstone 23 from the center of the workpiece W are stored (S563). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 2B, after the touch sensor 50 is turned to the measurement position, the feeler 54 and the detection pin are moved by controlling the second servo motor 92 and moving the table 14 horizontally. After the opposing position is reached, the first servo motor 82 is controlled to feed the grinding wheel base 20 to the table 14 side, and the grinding wheel base 20 is moved until the feeler 54 contacts the detection pin 34 as shown in FIG. 9B. (S564). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S565), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xb of the tip position of the spherical grindstone 23 from the center of W are stored (S566). Then, the grindstone platform 20 is retracted to the retracted end Xend.

Then, the exact length C of the feeler 54 is calculated from the contact position coordinate Xa of the reference grindstone 22b and the contact position coordinate Xb of the touch sensor 50 by the equation (5), and the distance C from the rotation axis Q to the measuring head 52 is calculated. Store in the memory 64. (S567).
Next, as shown in FIG. 10 (A), the spherical grindstone 23 contacts the detection pin 34 in the direction parallel to the grindstone axis O by simultaneously controlling the table and grindstone two axes while giving a minute cut in the X-axis direction. The grindstone table 20 is moved until it is done (S568). This contact feed is continued until a contact signal is detected (No in S569). When the contact between the detection pin 34 and the outer periphery of the spherical grindstone 23 is detected by the AE sensor 36 and the contact signal is input via the amplifier 72 (Yes in S569), the grindstone table and the table 14 are moved. While stopping, the contact position coordinates of the spherical grindstone 23, that is, the coordinates Xc of the tip position of the spherical grindstone 23 from the center of the workpiece W are stored (S570). Then, the grindstone platform 20 is retracted to the retracted end Xend.

  Next, as shown in FIG. 10B, after the touch sensor 50 is turned to the measurement position, the feeler 54 and the detection pin are moved by controlling the second servo motor 92 and moving the table 14 horizontally. After the opposing position is reached, the first servo motor 82 is controlled to feed the grinding wheel base 20 to the table 14 side, and the grinding wheel base 20 is moved until the feeler 54 contacts the detection pin 34 as shown in FIG. (S571). When the contact between the detection pin 34 and the feeler 52 is detected and the contact signal is input (Yes in S572), the movement of the table 14 is stopped and the contact position coordinates of the touch sensor 50, that is, the workpiece is detected. The coordinates Xd of the tip position of the spherical grindstone 23 from the center of W are stored (S573). Then, the grindstone platform 20 is retracted to the retracted end Xend. And the diameter R1 of an actual spherical grindstone is calculated | required by Formula (6) (S574).

  In order to measure the amount of wear generated during machining, the diameter of the spherical grindstone 23 measured this time from the diameter R0 (temporary diameter here) of the spherical grindstone 23 measured previously before being stored in the memory 64. The amount of change ΔR (= R0−R1) of the grindstone diameter is calculated by subtracting R1 (S575), and this value ΔR is stored, and the diameter R0 of the spherical grindstone 23 at the time of previous measurement is calculated this time. This is replaced with the diameter R1 of the spherical grindstone 23 obtained in (S576). Then, the X-direction component ΔRx of the change amount ΔR is obtained by Expression (7) (S577). Then, based on the X direction component ΔRx of the diameter change amount ΔR of the spherical grindstone 23, the position (= Xend−ΔRx) where the grindstone base 20 is advanced is updated to the retreat end Xend of the new grindstone base 20 (S578). .

  The technical idea of the present invention is that the reference grindstone 22b having a known diameter (and / or side surface position) and not involved in the grinding of the workpiece W is arranged coaxially with the grinding grindstone 22a and the position of the outer peripheral surface of the reference grindstone 22b. By comparing the position of the outer peripheral surface of the grinding wheel 22a worn by grinding, even if thermal displacement occurs in the rotation axis of the grinding wheel 22a, the influence of this thermal displacement is eliminated, and the diameter (and / or / Alternatively, the side surface position) can be accurately obtained.

  And as a method of calculating | requiring the position of the outer peripheral surface of the reference grindstone 22b and the outer peripheral surface of the grinding grindstone 22a, in the embodiment of this invention mentioned above, the outer peripheral surface of the reference grindstone 22b and the outer peripheral surface of the grinding grindstone are used as the detection pins 34 and 35. The vibration generated at this time is detected using a vibration detector (AE sensor) 36. As another method, the detection pins 34 and 35 are slightly ground with a reference grindstone, and the ground positions are measured by the touch sensor 50. Next, a method in which a predetermined amount is fed to the detection pins 34 and 35 by the worn grinding wheel 22b and the positions of the ground detection pins 34 and 35 are measured by the touch sensor 50 may be used. Since the difference between the difference between the positions of the detection pins 34 and 35 obtained by the measurement and the predetermined amount corresponds to the wear amount of the grinding wheel 22b, the diameter (and / or the side surface) of the grinding wheel 22b depends on the wear amount. (Position) may be obtained.

  In the above-described embodiment, the example in which the present invention is applied to the cylindrical grinding machine 10 has been described. However, the present invention can be used for a processing apparatus using a rotating tool in addition to the grinding wheel 20. Other processing devices include a milling machine using a milling tool as a rotary tool, a machining center, and the like.

The top view which shows the outline | summary of the cylindrical grinding machine which concerns on embodiment. Operation | movement explanatory drawing in the truing and grindstone diameter correction | amendment which concern on 1st Embodiment. The flowchart which shows the main operation | movement of a cylindrical grinder. The flowchart which shows the main operation | movement of a cylindrical grinder. The flowchart which shows the main operation | movement of a cylindrical grinder. The flowchart which shows the operation | movement at the time of truing which concerns on 1st Embodiment. The flowchart which shows the operation | movement of the grindstone diameter correction | amendment which concerns on 1st Embodiment. Operation | movement explanatory drawing in the truing and grindstone diameter correction | amendment which concern on 2nd Embodiment. Operation | movement explanatory drawing in the truing and grindstone diameter correction | amendment which concern on 2nd Embodiment. Operation | movement explanatory drawing in the truing and grindstone diameter correction | amendment which concern on 2nd Embodiment. The flowchart which shows the operation | movement at the time of truing which concerns on 2nd Embodiment. The flowchart which shows the operation | movement at the time of truing which concerns on 2nd Embodiment. The flowchart which shows the operation | movement of the grindstone diameter correction | amendment which concerns on 2nd Embodiment. Illustration. The flowchart which shows the operation | movement of the grindstone diameter correction | amendment which concerns on 2nd Embodiment. Illustration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Cylindrical grinding machine, 12 ... Bed, 14 ... Table, 16 ... Main shaft base, 17 ... Main shaft, 17a ... Chuck, 18 ... Tailstock, 18a ... Center, 20 ... Grinding wheel base (tool table), 22 ... Grinding wheel , 22a ... grinding wheel (rotary tool), 22b ... reference wheel (reference tool), 23 ... spherical wheel, 30 ... contact detector, 32 ... detection pin head, 34, 35 ... detection pin, 36 ... vibration detector (AE sensor) 40 ... truing device, 44 ... truing tool, 50 ... touch sensor, 52 ... feeler, 54 ... measuring head, 60 ... numerical control device, 62 ... central control device, 64 ... memory, 66, 68 ... interface, DESCRIPTION OF SYMBOLS 70 ... Input device, 72 ... Amplifier, 80 ... 1st motor drive circuit, 82 ... 1st servo motor, 84 ... 1st encoder, 90 ... 2nd motor drive circuit, 92 ... 2nd servo model Data, 94 ... the second encoder.

Claims (5)

A tool table on which a rotating tool is rotatably supported around the tool axis;
A table for holding the workpiece;
In a processing apparatus for processing a workpiece by moving the tool table and the table relative to each other in a direction in which they are separated from each other with reference to the positions of the outer peripheral surface and / or the tool side surface of the rotary tool
A reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter and / or tool width in advance, a detection pin fixed to the table, and an outer peripheral surface and / or a tool side surface of the reference tool toward the detection pin Means for storing as a reference position a position where the outer peripheral surface and / or the tool side surface of the reference tool is contacted or cut into the detection pin, and the rotary tool is moved from the reference position toward the detection pin; Means for storing a position at which an outer peripheral surface and / or a tool side surface of the rotary tool is in contact with or cut into the reference pin as a feed position and storing a movement amount of the rotary tool moved from the reference position; A means for calculating a difference between the reference position and the feed position, calculating a wear amount of the rotary tool from a deviation between the difference and the moving amount, and based on the wear amount of the rotary tool. Processing apparatus characterized by comprising a means for determining the size and or side position of the tool. A tool table on which a rotating tool is rotatably supported around the tool axis;
A table for holding the workpiece;
In a processing apparatus for processing a workpiece by moving the tool table and the table relative to each other in the X-axis direction with reference to the position of the outer peripheral surface of the rotary tool,
A reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance;
A touch sensor extending toward the table on the grinding wheel platform;
A detection pin fixed to the table so as to be able to contact the touch sensor;
Reference tool contact position storage means for storing a contact position of the reference rotary tool to the detection pin;
First contact position storage means for detecting contact of the end surface of the detection pin with a touch sensor after the contact with the detection pin by the reference rotary tool, and storing the contact position;
Based on the contact position stored in the reference tool contact position storage means and the contact position stored in the first contact position storage means, the relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor is calculated. First relative distance calculation means;
Touch sensor distance calculation means for calculating a distance from the tool axis to the tip of the touch sensor from the relative distance calculated by the first relative distance calculation means and the diameter of the reference rotary tool;
Tool contact position storage means for storing a contact position of the rotary tool to the detection pin;
A second contact position storage means for detecting contact of the end face of the detection pin with a touch sensor after the contact with the detection pin by the rotary tool, and storing the contact position;
A second calculating the relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the tool contact position storage means and the contact position stored in the second contact position storage means; A relative distance calculation means;
Rotating tool diameter calculating means for calculating the diameter of the rotating tool based on the relative distance calculated by the second relative distance calculating means and the distance from the tool axis to the tip of the touch sensor calculated by the touch sensor distance calculating means. When,
Position changing means for changing the position of the outer peripheral surface of the rotating tool based on the diameter of the rotating tool calculated by the rotating tool diameter calculating means;
A processing apparatus comprising: A tool table that rotatably supports a rotary tool having a spherical blade surface with a predetermined diameter from the center of the tool on the outer peripheral surface;
A table for holding the workpiece;
A processing apparatus for processing a workpiece with the rotary tool by moving the tool table and the table relative to each other in the X-axis direction and the Z-axis direction orthogonal to the X-axis direction with respect to the outer peripheral surface of the rotary tool. In
A reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance;
An X axis detection pin and a Z axis detection pin fixed to the table and extending along the X axis and the Z axis;
Side distance storage means for storing the distance from the tool center of the rotary tool to the side of the reference rotary tool or the rotary tool;
X-axis contact position storage means for storing a contact position of the outer peripheral surface of the reference rotary tool to the X-axis detection pin;
Z-axis contact position storage means for storing the contact position of the reference rotary tool or the side surface of the rotary tool to the Z-axis detection pin;
The diameter of the reference tool, the distance from the tool center of the rotating tool stored in the side distance storage means to the side surface of the reference rotating tool or the rotating tool, and the cutting position to the X-axis detection pin and the Z-axis detection pin Coordinate correction means for calculating the correction coordinates of the tool center of the rotary tool based on
A processing apparatus comprising: A tool table on which a rotating tool is rotatably supported around the tool axis;
A table for holding the workpiece;
In a processing apparatus for processing a workpiece by moving the tool table and the table relative to each other in the X-axis direction with reference to the position of the outer peripheral surface of the rotary tool,
A reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance;
A touch sensor extending toward the table on the grinding wheel platform;
A detection pin fixed to the table so as to be able to contact the touch sensor;
Reference tool contact position storage means for storing a contact position of the reference rotary tool to the detection pin;
First contact position storage means for detecting contact of the end surface of the detection pin with a touch sensor after the contact with the detection pin by the reference rotary tool, and storing the contact position;
Based on the contact position stored in the reference tool contact position storage means and the contact position stored in the first contact position storage means, the relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor is calculated. First relative distance calculation means;
Touch sensor distance calculation means for calculating a distance from the tool axis to the tip of the touch sensor from the relative distance calculated by the first relative distance calculation means and the diameter of the reference rotary tool;
Tool contact position storage means for storing a contact position of the rotary tool to the detection pin;
A second contact position storage means for detecting contact of the end face of the detection pin with a touch sensor after the contact with the detection pin by the rotary tool, and storing the contact position;
A second calculating the relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the tool contact position storage means and the contact position stored in the second contact position storage means; A relative distance calculation means;
Rotating tool diameter calculating means for calculating the diameter of the rotating tool based on the relative distance calculated by the second relative distance calculating means and the distance from the tool axis to the tip of the touch sensor calculated by the touch sensor distance calculating means. When,
A processing apparatus comprising tool correcting means for cutting a predetermined amount of the truing tool into an end face of the rotating tool based on the diameter of the rotating tool calculated by the rotating tool diameter calculating means. A tool base that rotatably supports a rotary tool having a spherical blade surface with a predetermined diameter from the tool center of the rotary tool on the outer peripheral surface;
A table for holding the workpiece;
A processing apparatus for processing a workpiece with the rotary tool by moving the tool table and the table relative to each other in the X-axis direction and the Z-axis direction orthogonal to the X-axis direction with respect to the outer peripheral surface of the rotary tool. In
A reference tool that is supported coaxially with the rotation axis of the rotary tool and has a known diameter in advance;
An X axis detection pin and a Z axis detection pin fixed to the table and extending along the X axis and the Z axis;
Side distance storage means for storing the distance from the center of the rotary tool to the side of the reference rotary tool or rotary tool;
X-axis contact position storage means for storing a contact position of the outer peripheral surface of the reference rotary tool to the X-axis detection pin;
Z-axis contact position storage means for storing the contact position of the reference rotary tool or the side surface of the rotary tool to the Z-axis detection pin;
In the diameter of the reference tool, the distance from the center of the rotary tool stored in the side distance storage means to the side of the reference rotary tool or the rotary tool, and the cutting position to the X-axis detection pin and the Z-axis detection pin A coordinate correcting means for calculating a correction coordinate of the center of the rotary tool based on;
A first contact position storage means for detecting contact of the end surface of the X-axis detection pin with a touch sensor after the contact with the X-axis detection pin by the reference rotary tool, and storing the contact position;
Based on the X-axis contact position stored in the X-axis contact position storage means and the contact position stored in the first contact position storage means, the relative distance between the outer peripheral surface of the reference rotary tool and the tip of the touch sensor is calculated. First relative distance calculating means for calculating;
Touch sensor distance calculation means for calculating a distance from the tool center to the tip of the touch sensor from the relative distance calculated by the first relative distance calculation means and the diameter of the reference rotary tool;
Incision execution means for making contact with the X-axis detection pin with reference to the correction coordinates of the center of the rotary tool by the coordinate correction means;
Tool contact position storage means for storing a contact position to the X-axis detection pin by the cutting execution means;
A second contact position storage means for detecting contact of the end surface of the X-axis detection pin with a touch sensor after the contact with the X-axis detection pin by the rotary tool, and storing the contact position;
A second calculating the relative distance between the outer peripheral surface of the rotary tool and the tip of the touch sensor based on the contact position stored in the tool contact position storage means and the contact position stored in the second contact position storage means; A relative distance calculation means;
A rotating tool spherical diameter for calculating the spherical diameter of the rotating tool based on the relative distance calculated by the second relative distance calculating means and the distance from the tool center to the tip of the touch sensor calculated by the touch sensor distance calculating means. Computing means;
Spherical truing means for truing the rotary tool based on the tool center of the rotary tool calculated by the coordinate correction means and the spherical diameter calculated by the rotary tool spherical diameter calculation means;
A processing apparatus comprising:

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