JP5208669B2 - Boring machine and hole machining method - Google Patents

Description

  The present invention relates to a boring apparatus and a hole drilling method.

Conventionally, as the boring apparatus, for example, there are those described in Japanese Patent Application Laid-Open No. 6-285705 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-307216 (Patent Document 2). The boring apparatus described in Patent Document 1 is provided so that the precision finishing tool can be moved in the radial direction with respect to the holder body. Moreover, the boring apparatus described in Patent Document 2 is provided so that the precision finishing tool bit and the intermediate finishing tool bit can be moved in the radial direction with respect to the holder body.
JP-A-6-285705 JP 2002-307216 A

  Generally, a boring apparatus described in Patent Document 1 exists. This type of boring device maintains the precision of precision finishing by correcting the amount of protrusion of the precision finishing tool from the holder body even if the tip attached to the precision finishing tool is worn. it can. However, in the boring apparatus in which the intermediate finishing tool is fixed, there is a problem that the life of the tip of the precision finishing tool is shortened.

  Therefore, as a result of intensive studies on the cause of the short tool life of the precision finishing tool, the present inventors have derived that the cause is as follows. In the boring apparatus described in Patent Document 1, the fine finishing tool bit is provided so as to be movable in the radial direction with respect to the holder body, but the intermediate finishing tool bit is provided fixed to the holder body. It has been. As a matter of course, by machining the workpiece, not only the fine finishing tool bit but also the intermediate finishing tool chip are worn. In other words, the machining diameter of the intermediate finishing tool with the insert gradually decreases. On the other hand, the precision finishing machining tool has a constant precision finishing machining diameter by moving in the radial direction with respect to the holder body.

  Therefore, the difference between the fine finishing diameter and the intermediate finishing diameter gradually increases. In other words, the machining allowance (corresponding to the cutting diameter) of the fine finishing tool tip gradually increases. For this reason, the wear of the precision finishing tool tip has increased. The present inventors have found that this is the cause of the reduction in the life of the tip of the precision finishing tool. In other words, the present inventors reduce the amount of change in the machining allowance due to the tip of the precision finishing tool even if the tip of the finishing tool bit wears out, thereby prolonging the life of the precision finishing tool tip. I found that it can be improved.

  By the way, Patent Document 2 describes a configuration in which the fine finishing tool bit and the intermediate finishing tool bit can be moved in the radial direction with respect to the holder body. Specifically, Patent Document 2 describes that it is easy to adjust the machining allowance with a precision finishing tool and the machining allowance with a medium finishing tool. However, the correction of both bytes is not described.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a boring apparatus and a hole drilling method capable of improving the life of a tip of a precision finishing tool.

Therefore, in order to solve the above problems, the features of the boring apparatus according to claim 1 are as follows:
A tool holder having a cutting tool provided on the outer peripheral surface of the holder body, and machining the hole in the workpiece by feeding the tool holder in the axial direction relative to the workpiece while rotating about the axis. In the boring machine,
The holder body;
A first tool provided on an outer peripheral surface of the holder body, provided so as to be movable in a radial direction of the holder body with respect to the holder body, and machining a hole of the workpiece in a first machining step When,
Provided on the outer peripheral surface of the holder body, provided so as to be movable in the radial direction of the holder body with respect to the holder body, and in a second machining step performed after the first machining step, A second bit to machine the hole,
Measuring means for measuring a hole in the workpiece after the second machining step;
When machining the next hole of the workpiece, based on the measurement result by the measuring means, the radial position of the first bite in the first machining step and the second in the second machining step Correction means for correcting the radial position of each tool,
It is to provide.

The feature of the invention according to claim 2 is that in claim 1,
The correction means determines a correction amount cumulative value of the radial position of the first bit based on a correction amount cumulative value of the radial position of the second bit.

The invention according to claim 3 is characterized in that in claim 2,
The correction means is to set a correction amount cumulative value of the radial position of the first cutting tool to be smaller than a correction amount cumulative value of the radial position of the second cutting tool.

A feature of the invention according to claim 4 is that in any one of claims 1 to 3,
The machining process of the hole of the workpiece includes a precision finishing process for precisely finishing the hole of the workpiece, and a medium finishing process performed immediately before the precision finishing process,
The first processing step is the intermediate finishing processing step,
The second processing step is the fine finishing processing step.

A feature of the invention according to claim 5 is that in any one of claims 1 to 3,
The hole processing step of the workpiece is performed immediately before the precision finishing processing step for precisely finishing the hole of the workpiece, the intermediate finishing processing step performed immediately before the precision finishing processing step, and the intermediate finishing processing step. Including roughing process,
The first processing step is the intermediate finishing step and the roughing step,
The second processing step is the fine finishing processing step,
The first cutting tool includes a medium finishing tool that processes a hole in the workpiece in the intermediate finishing process and a roughing tool that processes a hole in the workpiece in the roughing process. .

Further, in order to solve the above-mentioned problem, the feature of the invention of the hole machining method according to claim 6 is
Using a tool holder having a cutting tool provided on the outer peripheral surface of the holder body, the hole of the workpiece is machined by feeding the tool holder in the axial direction relative to the workpiece while rotating the tool holder around the axis. In the hole drilling method,
A first machining step of machining a hole in the workpiece by a first bit provided on an outer peripheral surface of the holder main body and movable relative to the holder main body in a radial direction of the holder main body; ,
The hole of the workpiece is machined after the first machining step by a second bit provided on the outer peripheral surface of the holder main body and movable relative to the holder main body in the radial direction of the holder main body. A second processing step to perform,
A measuring step of measuring the hole of the workpiece by a measuring means after the second machining step;
With
In the first machining step, when machining the next hole of the workpiece, the radial position of the first bit is corrected based on the measurement result by the measuring means to form the hole of the workpiece. Processed
In the second machining step, when machining the hole of the next workpiece, the radial position of the second tool is corrected based on the measurement result by the measuring means, and the hole of the workpiece is corrected. Is to process.

  According to the invention according to claim 1 configured as described above, the two types of tools, the first tool and the second tool, are configured to be movable in the radial direction with respect to the holder body. Therefore, when the tip of the first bite is worn, the radial position of the first bite is corrected, and when the tip of the second bite is worn, the radial position of the second bit is corrected. can do. Therefore, when the second machining step is a fine finishing machining step, a change in the machining allowance due to the second bite tip in the fine finishing machining step can be suppressed as compared with the conventional case. Thereby, the lifetime of the chip of the second byte can be improved.

  Furthermore, according to the present invention, it is possible to suppress the machining allowance of the first cutting tool tip from being changed by the workpiece, and to suppress the machining allowance of the second cutting tool tip from being changed by the workpiece. Therefore, the chip of the first byte and the chip of the second byte can be set so as to have almost the same lifetime. That is, according to the present invention, since the replacement of the first byte chip and the replacement of the second byte chip can be performed simultaneously, the facility stop time can be shortened.

  Furthermore, the workpiece is measured only after the second machining step, which is a subsequent step, and the radial positions of the first and second tools are corrected based on the measurement result. That is, the radial position of the first bit and the second bit is corrected by one measurement. By the way, correction of the radial position of the first tool can be performed with high accuracy by measuring the workpiece after the first machining step. However, if it does in this way, a measurement process will be 2 times after a 1st processing process and a 2nd processing process. This increases the time (cycle time) required for machining measurement of the workpiece. On the other hand, according to the present invention, not only the second byte but also the first byte is corrected by only one measurement after the second machining step. Thereby, it is not necessary to increase the number of times of measurement compared to the conventional case. Therefore, it is possible to prevent the cycle time from being prolonged.

  However, the correction of the first bite in the first machining step is performed based on the result measured after the second machining step. However, since the wear amount of the tip of the first bit is approximately proportional to the wear amount of the tip of the second bit, if the wear amount of the second bit can be measured, the wear of the tip of the first bit The amount can be guessed to some extent. Therefore, sufficient accuracy can be obtained by correcting the radial position of the first tool based on the measurement after the second machining step. In the present invention, the radial position of the first bit means the radial position of the holder main body with respect to the holder main body of the first bit, and the radial position of the second bit means the radial position of the second bit. It means the radial position of the holder body relative to the holder body.

  According to the second aspect of the present invention, the correction amount cumulative value of the radial position of the first bit can be made sufficiently appropriate. As described above, the wear amount of the tip of the first bite and the wear amount of the second bite are substantially proportional. The wear amount of the tip of the second bit corresponds to the correction amount cumulative value of the radial position of the second bit. In other words, since the accumulated correction value of the radial position of the first bit is determined after referring to the correction value accumulated value of the radial position of the second bit, the wear amount of the tip of the first bit Without directly measuring the correction amount, the correction amount cumulative value of the radial position of the first tool can be determined with sufficient accuracy.

  Here, the correction amount accumulated value of the radial position of the first bit is the radial position of the first bit in the initial state in which the tip of the first bit is not worn, and the corrected first bit It is a difference with the radial direction position. The cumulative correction value of the radial position of the second bit is the radial position of the second bit in the initial state where the tip of the second bit is not worn, and the corrected second bit of the second bit. It is the difference from the radial position.

  According to the invention which concerns on Claim 3, it can prevent that the chip | tip of a 1st cutting tool exceeds the process diameter which should be processed with the chip | tip of a 2nd cutting tool. If the tip of the first bit exceeds the machining diameter to be machined by the tip of the second bit, the workpiece cannot be formed into the target shape. That is, the workpiece is a defective product. Thus, by doing the above, it is possible to prevent the production of defective workpieces.

  According to the fourth aspect of the present invention, the cutting tool in the fine finishing process and the cutting tool in the intermediate finishing process are corrected. Thereby, the lifetime of the chip | tip of the 2nd cutting tool in a precision finishing process can be improved reliably.

  According to the fifth aspect of the present invention, the cutting tool in the fine finishing process, the cutting tool in the intermediate finishing process, and the cutting tool in the roughing process are corrected. Thereby, the lifetime of the chip | tip of the 2nd cutting tool in a precision finishing process can be improved reliably. Furthermore, the life of the intermediate finishing tool in the intermediate finishing process can be reliably improved.

  The invention according to claim 6 corresponds to a processing method to which the boring apparatus according to claim 1 described above is applied. That is, according to the invention concerning Claim 7, there exists an effect similar to the effect by the boring apparatus concerning Claim 1. That is, the lifetime of the second byte chip can be improved. Furthermore, since the replacement of the first byte chip and the replacement of the second byte chip can be performed simultaneously, the facility downtime can be shortened. Furthermore, it is possible to prevent the cycle time from being prolonged.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which a boring apparatus and a hole drilling method of the present invention are embodied will be described with reference to the drawings.

<First embodiment>
(Overall configuration of boring machine)
The overall configuration of the boring apparatus according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a front view of the boring apparatus. FIG. 2 is a right side view of the boring apparatus. Here, the workpiece W processed by the boring apparatus of this embodiment is a cylinder block of an engine, and the processing site is a bore portion of the cylinder block. Here, an example of a boring apparatus that targets a 4-cylinder block and that can simultaneously process every two cylinders will be described.

  As shown in FIGS. 1 and 2, the boring apparatus according to this embodiment mainly includes a bed 10, a column 20, a spindle head 30, a jig table 50, a measuring instrument 60, and a measuring table 70. And a control device 80.

  The bed 10 is formed in a thick flat plate shape by casting and is fixed on the floor. The column 20 includes a column main body 21, a Z-axis feed ball screw (not shown), and a Z-axis feed motor 22. The column main body 21 is formed in a substantially rectangular parallelepiped shape from a casting, is erected on the bed 10 and supports the spindle head 30 so as to be slidable. Two guide rails 21a are formed on the side surfaces of the column main body 21 (the front face in FIG. 1 and the left face in FIG. 2) so as to extend in the vertical direction and in parallel. The Z-axis feed ball screw is supported by the column body 21 so as to extend vertically between the two guide rails 21a and to be rotatable about the Z axis (around the vertical axis). . The Z-axis feed motor 22 is disposed at the upper end of the column body 21 and is coupled to the upper end of the Z-axis feed ball screw so as to rotationally drive the Z-axis feed ball screw.

  The spindle head 30 includes a spindle head body 31, first and second spindles 32 and 33, first and second tool holders 34 and 35, first and second draw bars 36 and 37, and a rotary head. A motor 38, a rotation transmission mechanism 39, first and second protruding motors 40 and 41, and first and second protruding mechanisms 42 and 43 are provided. The detailed configuration of the spindle head 30 will be described later. Here, an outline of the spindle head 30 will be described.

  The spindle head main body 31 is supported so as to be slidable in the vertical direction with respect to the column main body 21. The main spindle head body 31 is provided with first and second main spindles 32 and 33 so as to be rotatable about the vertical axis (around the X axis). First and second tool holders 34 and 35 are fixed to lower ends of the first and second main shafts 32 and 33. The first and second tool holders 34 and 35 include a holder main body 101 and a plurality of cutting tools 102 to 105 provided on the outer peripheral surface of the holder main body 101. Chips 102c to 105c are attached to the bytes 102 to 105, respectively. In other words, the bores (holes) of the cylinder block W are machined by rotating the tool holders 34 and 35 around their respective axis centers and sending them in the axial direction to the cylinder block W that is a workpiece. Here, the rotation of the first and second main shafts 32 and 33 is performed by driving the rotation motor 38 via the rotation transmission mechanism 39.

  Further, the fine finishing tool 105 and the intermediate finishing tools 103 and 104 are provided so as to be movable in the radial direction of the holder body 101 with respect to the holder body 101. That is, the fine finishing bit 105 and the intermediate finishing bit 103, 104 can correct the radial position with respect to the holder body 101 in accordance with the wear amount of the respective chips 105c, 103c, 104c. . The fine finishing bit 105 and the intermediate finishing bit 103, 104 are moved in the radial direction via the first and second draw bars 36, 37 and the first and second protruding mechanisms 42, 43. This is done by driving the second protruding motors 40 and 41.

  The jig table 50 is disposed on the bed 10, and is located on the front side of the column main body 21 (the front side of the hand in FIG. 1) and below the spindle head main body 31. The jig table 50 is provided so as to be movable in the X-axis direction between both ends of the column main body 21 with respect to the bed 10. Specifically, the jig table 50 includes an X-axis feed ball screw and an X-axis feed motor. Then, the jig table 50 clamps the workpiece (cylinder block) that has been carried into the boring apparatus after finishing the previous process.

  The measuring instrument 60 is composed of, for example, a touch sensor and is provided next to the column 20 on the bed 10. Specifically, the measuring instrument 60 is provided on the carry-out side of the cylinder block W in the column 20. The measuring instrument 60 is movable in a direction (X-axis direction) approaching or separating from the upper surface of the bed 10. The measuring instrument 60 measures the inner diameter of the bore portion of the cylinder block W. Specifically, among the bore portions of the four cylinders, the bore portions of the second and fourth cylinders from the left side in FIG. 1 are measured. That is, the measuring instrument 60 measures the rear part of the part processed by the first tool holder and the rear part of the part processed by the second tool holder.

  The measurement table 70 is disposed on the bed 10 and is located directly below the measuring instrument 60. That is, the measurement table 70 is a table on which the cylinder block W that has been processed is placed. The measurement table 70 is provided so as to be movable with respect to the bed 10 in the X-axis direction. Specifically, the measurement table 70 includes an X-axis feed ball screw and an X-axis feed motor.

  The control device 80 includes a Z-axis feed motor 22 for driving the spindle head 30, a Z-axis feed motor for driving the measuring instrument 60, a rotation motor 38 for the first and second spindles 32 and 33, and cutting tools 102 to 105. Control of the protruding motors 40 and 41, the X-axis feed motor of the jig table 50, and the X-axis feed motor of the measurement table 70 is performed. That is, the control device 80 controls the positioning of each moving member by controlling each motor. The detailed configuration of the control device 80 will be described later.

(Detailed configuration of spindle head 30)
A detailed configuration of the spindle head 30 will be described with reference to FIGS. 3 to 6 in addition to FIGS. 1 and 2. 3 is an AA enlarged cross-sectional view of FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG. FIG. 5 is a diagram showing a state where the CC cross-sectional view of FIG. 4 is turned 90 ° clockwise. 6 is a cross-sectional view taken along the line DD of FIG.

  As described above, the spindle head 30 includes the spindle head body 31, the first and second spindles 32 and 33, the first and second tool holders 34 and 35, the first and second draw bars 36, 37, a rotation motor 38, a rotation transmission mechanism 39, first and second protrusion motors 40 and 41, and first and second protrusion mechanisms 42 and 43.

The spindle head main body 31 is formed in a substantially rectangular parallelepiped shape by casting. A ball screw nut (not shown) is formed on the back surface (right side surface in FIG. 2) of the spindle head main body 31. This ball screw nut is screwed into a Z-axis feed ball screw attached to the column main body 21. That is, by rotating the Z-axis feed motor 22 attached to the column body 21, the Z-axis feed ball screw rotates, and the spindle head body 31 moves vertically with respect to the column body 21 along with the rotation. Move to. In the spindle head main body 31, through holes 31a extending in the vertical direction are formed at two places on the left and right in FIG. The pitch of the two through holes 31a is set to twice the pitch of the bore portion of the cylinder block W.
The first and second main shafts 32 and 33 each have the same cylindrical shape, and are rotatably inserted through the through holes 31a of the main shaft head body 31 via bearings.

  The first and second tool holders 34 and 35 are attached to the lower ends of the first and second main shafts 32 and 33, respectively. That is, the first and second tool holders 34 and 35 rotate with respect to the spindle head main body 31 as the first and second spindles 32 and 33 rotate. The first and second tool holders 34 and 35 have the same configuration. Therefore, the first tool holder 34 will be described with reference to FIGS.

  The first tool holder 34 includes a holder main body 101, a roughing cutting tool 102, a first intermediate finishing tool 103, a second intermediate finishing tool 104, a fine finishing tool 105, first to The third slide pieces 106 to 108, first to third movable pins 109 to 111, a rotation restricting pin 112, and a cap 113 are configured.

  As shown in FIGS. 5 and 6, the holder body 101 is formed in a cylindrical shape having a through hole in the central axis. On the outer peripheral surface of the holder main body 101, four notches 101a to 101d having a predetermined length in the axial direction are formed at equal intervals in the circumferential direction. The radial cross-sectional shapes of the notches 101a to 101d are substantially L-shaped in the circumferential direction of the holder main body 101 as shown in FIG. Each notch 101a-101d is formed with a female screw. Further, three notches 101b to 101d in the holder main body 101 are formed with through holes 101e to 101g penetrating the surfaces of the notches 101b to 101d and the inner peripheral surface of the holder main body 101. Furthermore, a through hole 101h penetrating from the outer peripheral surface toward the inner peripheral surface is formed in the upper portion of the notch 101a where the through holes 101e to 101g are not formed. That is, the through holes 101e to 101g and the through hole 101h are formed at different positions in the axial direction.

  The roughing cutting tool 102 includes a tip 102c for roughing the bore portion of the cylinder block W. Specifically, as shown in FIG. 5, the roughing cutting tool 102 includes a cutting tool body 102a, a mounting bolt 102b, and a tip 102c. The bit body 102a of the roughing tool 102 is formed in an elongated rectangular shape. The cutting tool body 102a is disposed in the notch 101a, and is fixed to the holder body 101 by screwing the mounting bolt 102b into the female screw of the holder body 101. As shown in FIG. 4, the cutting tool body 102 a can be accommodated in a notch 101 a of the holder body 101. That is, the cutting tool main body 102 a is located inside the circumscribed circle of the holder main body 101 in a state of being attached to the holder main body 101. The chip 102c is fixed to the lower side of the cutting tool body 102a so as to protrude outward from the outer peripheral surface of the cutting tool body 102a. The tip 102 c protrudes outward in the radial direction from the circumscribed circle of the holder body 101 in a state where the cutting tool body 102 a is fixed to the holder body 101. And the processing diameter by the chip | tip 102c only changes with abrasion of the chip | tip 102c.

  The first intermediate finishing bit 103 includes a chip 103c for performing intermediate finishing after roughing the bore portion of the cylinder block W. Specifically, as shown in FIG. 6, the first intermediate finishing bit 102 includes a bit body 103a, a mounting bolt 103b, and a tip 103c. The bit body 103a of the first intermediate finishing bit 103 is formed in an elongated rectangular shape as a whole and includes a flexible portion 103d. The flexible portion 103d is formed thinner than other portions by forming a groove. When the flexible portion 103d is bent and deformed, the other side can be displaced with respect to one side of the flexible portion 103d.

  The cutting tool body 103a is disposed in a notch 101b formed next to the notch 101a, and is fixed to the holder body 101 by screwing the mounting bolt 103b into the female screw of the holder body 101. The position where the attachment bolt 103b is inserted in the bite body 103a is above the flexible portion 103d. As shown in FIG. 4, the tool body 103 a can be accommodated in a notch 101 b of the holder body 101. That is, the cutting tool main body 103 a is positioned inside the circumscribed circle of the holder main body 101 in a state where it is attached to the holder main body 101. The chip 103c is fixed below the flexible portion 103d of the bite body 103a so as to protrude outward from the outer peripheral surface of the bite body 103a. The tip 103 c protrudes outward in the radial direction from the circumscribed circle of the holder body 101 in a state where the tool body 103 a is fixed to the holder body 101. Furthermore, when the flexible portion 103d is bent and deformed, the position of the radially outer end portion of the chip 103c moves radially outward. That is, the processing diameter by the chip 103c varies depending on the amount of deformation of the cutting tool body 103a and the wear of the chip 103c.

  Similar to the first intermediate finishing bit 103, the second intermediate finishing bit 104 includes a tip 104c for performing intermediate finishing after roughing the bore portion of the cylinder block W. Specifically, as shown in FIG. 6, the second intermediate finishing bit 104 includes a bit body 104a, a mounting bolt 104b, and a tip 104c. The bit body 104a of the second intermediate finishing bit 104 is formed in an elongated rectangular shape as a whole and includes a flexible portion 104d. The flexible portion 104d is formed thinner than other portions by forming a groove. When the flexible portion 104d is bent and deformed, the other side can be displaced with respect to one side of the flexible portion 104d.

  The bite body 104a is disposed in a notch 101d formed next to the notch 101a and on the back surface side of the notch 101b, and the mounting bolt 104b is screwed to the female screw of the holder body 101. It is fixed to the holder body 101. The position where the attachment bolt 104b is inserted in the bite body 104a is above the flexible portion 104d. As shown in FIG. 4, the cutting tool body 104 a can be accommodated in a notch 101 d of the holder body 101. That is, the cutting tool main body 104 a is located inside the circumscribed circle of the holder main body 101 in a state where it is attached to the holder main body 101. The tip 104c is fixed below the flexible portion 104d of the bite body 104a so as to protrude outward from the outer peripheral surface of the bite body 104a. The tip 104 c protrudes outward in the radial direction from the circumscribed circle of the holder body 101 in a state where the tool body 104 a is fixed to the holder body 101. Furthermore, when the flexible portion 104d is bent and deformed, the position of the radially outer end portion of the chip 104c moves radially outward. That is, the processing diameter by the tip 104c changes depending on the amount of bending deformation of the tool body 104a and the wear of the tip 104c.

  The fine finishing bit 105 includes a tip 105c for performing fine finishing after performing the medium finishing of the bore portion of the cylinder block W. Specifically, as shown in FIG. 5, the precision finishing bit 105 includes a bit body 105a, a mounting bolt 105b, and a tip 105c. The tool body 105a of the precision finishing tool 105 is formed in an elongated rectangular shape as a whole and includes a flexible portion 105d. The flexible portion 105d is formed thinner than other portions by forming a groove. When the flexible portion 105d is bent and deformed, the other side can be displaced with respect to one side of the flexible portion 105d.

  The bit body 105a is disposed in a notch 101c formed next to the notches 101b and 101d and on the back side of the notch 101a to which the roughing bit 102 is fixed, and the mounting bolt 105b is attached to the holder. The holder body 101 is fixed by screwing with the female screw of the body 101. The position where the mounting bolt 103c is inserted in the bite body 105a is above the flexible portion 105d. As shown in FIG. 4, the tool body 105 a can be accommodated in a notch 101 c of the holder body 101. That is, the cutting tool main body 105 a is located inside the circumscribed circle of the holder main body 101 in a state where it is attached to the holder main body 101. The chip 105c is fixed below the flexible portion 105d of the bite body 105a so as to protrude outward from the outer peripheral surface of the bite body 105a. The tip 105c protrudes outward in the radial direction from the circumscribed circle of the holder body 101 in a state where the tool body 105a is fixed to the holder body 101. Furthermore, when the flexible portion 105d is bent and deformed, the position of the radially outer end portion of the chip 105c moves radially outward. That is, the processing diameter by the chip 105c varies depending on the amount of deformation of the cutting tool body 105a and the wear of the chip 105c.

  As shown in FIGS. 5 and 6, each of the first to third slide pieces 106 to 108 has an L shape. One side of the L shape of the first to third slide pieces 106 to 108 is engaged with the lower end surface of the holder body 101, and the other side of the L shape of the first to third slide pieces 106 to 108 is engaged. The holder body 101 is in contact with the inner peripheral surface.

  Specifically, as shown in FIG. 6, the first slide piece 106 is disposed in a first reduced diameter tapered groove 202 of the draw bars 36 and 37, which will be described later, so that the inside of the through hole 101e in the circumferential direction. It is located at a position to close the circumferential opening. Further, as shown in FIG. 6, the second slide piece 107 is disposed in a second reduced diameter tapered groove 203 of the draw bars 36 and 37 described later, thereby opening the inner peripheral side opening of the through hole 101 f in the circumferential direction. It is located at the position to close. As shown in FIG. 5, the third slide piece 108 is disposed in a diameter-expanded tapered groove 204 of the draw bars 36 and 37 to be described later, thereby closing the inner peripheral side opening of the through hole 101 g in the circumferential direction. positioned.

  The first to third movable pins 109 to 111 are fitted into the through holes 101 e to 101 g formed in the holder main body 101. These first to third movable pins 109 to 111 are movable in the radial direction of the holder body 101 with respect to the holder body 101. The radially outer end of the first movable pin 109 is in contact with the bit body 103a of the first intermediate finishing bit 103, and the radially inner end of the first movable pin 109 is the first slide. It abuts on the piece 106. The radially outer end of the second movable pin 110 abuts against the bit body 104a of the second intermediate finishing bit 104, and the radially inner end of the second movable pin 110 is the second slide piece 107. Abut. The radially outer end of the third movable pin 111 is in contact with the tool body 105 a of the precision finishing tool 105, and the radially inner end of the third movable pin 111 is in contact with the third slide piece 108. ing.

The rotation regulating pin 112 is fitted and fixed in the through hole 101h. The radially inner end of the rotation restricting pin 112 protrudes radially inward from the inner peripheral surface of the holder body 101 and is engaged with the key groove 201 of the draw bars 36 and 37. That is, the rotation restricting pin 112 has a function of restricting relative rotation between the holder main body 101 and the draw bars 36 and 37.
The cap 113 is fixed to the lower end surface of the holder main body 101 and covers the lower end side of the holder main body 101.

  The first and second drawbars 36 and 37 are inserted through the hollow portions of the first and second main shafts 32 and 33, are provided so as not to rotate relative to the first and second main shafts 32 and 33, and The first and second main shafts 32 and 33 are provided so as to be relatively movable in the axial direction. The first and second drawbars 36 and 37 have the same configuration. Accordingly, the first draw bar 36 will be described with reference to FIGS.

  The first draw bar 36 is made of a solid shaft member. The first draw bar 36 is inserted through the hollow portion of the first main shaft 32 and the hollow portion of the holder main body 101. A key groove 201, a first reduced diameter tapered groove 202, a second reduced diameter tapered groove 203, and an enlarged diameter tapered groove 204 are formed on the outer peripheral surface on the lower end side of the first draw bar 36. Yes.

  As shown in FIG. 5, the key groove 201 has a predetermined length in the axial direction, and is formed so that the groove bottom of the key groove 201 is parallel to the axial direction. The key groove 201 is formed at a position corresponding to the inner peripheral opening of the through hole 101 h formed in the holder main body 101. The rotation restriction pin 112 is engaged with the key groove 201. That is, when the rotation restricting pin 112 is engaged with the key groove 201, relative rotation between the holder main body 101 and the draw bar 36 is restricted. However, the holder body 101 to which the rotation restricting pin 112 is fixed can be moved relative to the draw bar 36 in the axial direction by the length of the key groove 201.

  As shown in FIG. 6, the first reduced diameter tapered groove 202 has a predetermined length in the axial direction from the lower end of the draw bar 36 at a position shifted by 90 ° in the circumferential direction from the key groove 201. The groove bottom of the diameter-reduced taper groove 202 is formed so as to decrease in diameter downward in FIG. A first slide piece 106 is slidably fitted in the first reduced diameter tapered groove 202. The groove depth of the first reduced diameter tapered groove 202 is slightly larger than the radial thickness of the sliding portion of the first slide piece 106 on the lower end side of the draw bar 36, and on the upper end side of the draw bar 36. The first slide piece 106 is formed to have approximately the same thickness as the radial thickness of the sliding portion. That is, the first slide piece 106 moves in the radial direction of the holder body 101 as the draw bar 36 moves relative to the holder body 101 in the axial direction.

  Specifically, when the draw bar 36 moves from the upper side to the lower side with respect to the holder main body 101, the first slide piece 106 moves radially outward with respect to the holder main body 101. At this time, the first slide piece 106 pushes the first movable pin 109 outward in the radial direction. As a result, the bit body 103a of the first intermediate finishing bit 103 is bent and deformed radially outward. That is, by this operation, the position of the radially outer end of the tip 103c of the first intermediate finishing bit 103 is moved radially outward.

  On the other hand, when the draw bar 36 moves from the lower side to the upper side with respect to the holder main body 101, the first slide piece 106 moves inward in the radial direction with respect to the holder main body 101. At this time, the first slide piece 106 pulls back the first movable pin 109 radially inward by the elastic return of the cutting tool body 103a. That is, by this operation, the position of the radially outer end of the tip 103c of the first intermediate finishing bit 103 is moved radially inward.

  As shown in FIG. 6, the second diameter-reduced taper groove 203 is formed at a position shifted by 90 ° in the circumferential direction from the key groove 201 at a position on the back surface side of the first diameter-reduced taper groove 202. It has a predetermined length in the axial direction from the lower end, and is formed so that the groove bottom of the second reduced diameter tapered groove 203 is reduced in diameter downward in FIG. The shape of the second reduced diameter tapered groove 203 is the same as that of the first reduced diameter tapered groove 202. A second slide piece 107 is slidably fitted in the second reduced diameter tapered groove 203. The groove depth of the second reduced diameter tapered groove 203 is slightly larger than the radial thickness of the sliding portion of the second slide piece 107 on the lower end side of the draw bar 36, and on the upper end side of the draw bar 36. The second slide piece 107 is formed to have substantially the same thickness as the radial thickness of the sliding portion. That is, as the draw bar 36 moves relative to the holder body 101 in the axial direction, the second slide piece 107 moves in the radial direction of the holder body 101.

  Specifically, when the draw bar 36 moves from the upper side to the lower side with respect to the holder main body 101, the second slide piece 107 moves radially outward with respect to the holder main body 101. At this time, the second slide piece 107 pushes the second movable pin 110 radially outward. As a result, the bit body 104a of the second intermediate finishing bit 104 is bent and deformed radially outward. That is, by this operation, the position of the radially outer end of the tip 104c of the second intermediate finishing bit 104 is moved radially outward.

  On the other hand, when the draw bar 36 moves from the lower side to the upper side with respect to the holder main body 101, the second slide piece 107 moves radially inward with respect to the holder main body 101. At this time, the second slide piece 107 pulls back the second movable pin 110 radially inward by the elastic return of the cutting tool body 104a. That is, by this operation, the position of the radially outer end of the tip 104c of the second intermediate finishing bit 104 is moved radially inward.

  As shown in FIG. 5, the diameter-expanded taper groove 204 has a draw bar at a position shifted by 90 ° in the circumferential direction from the first and second diameter-reduced taper grooves 202 and 203 at a position on the back surface side of the key groove 201. It has a predetermined length in the axial direction from the lower end of 36, and is formed so that the groove bottom of the diameter-expanded taper groove 204 increases in diameter downward in FIG. The third slide piece 108 is slidably fitted in the diameter-expanded taper groove 204. The groove depth of the diameter-expanded tapered groove 204 is formed to be approximately the same as the radial thickness of the sliding portion of the third slide piece 108 on the lower end side of the draw bar 36, and on the upper end side of the draw bar 36. The thickness of the slide piece 108 is slightly larger than the thickness in the radial direction. In other words, the third slide piece 108 moves in the radial direction of the holder body 101 as the draw bar 36 moves relative to the holder body 101 in the axial direction.

  Specifically, when the draw bar 36 moves from the lower side to the upper side with respect to the holder main body 101, the third slide piece 108 moves radially outward with respect to the holder main body 101. At this time, the third slide piece 108 pushes the third movable pin 111 outward in the radial direction. As a result, the tool body 105a of the precision finishing tool 105 is bent and deformed radially outward. That is, by this operation, the position of the radially outer end of the tip 105c of the precision finishing bit 105 is moved radially outward.

  On the other hand, when the draw bar 36 moves from the upper side to the lower side with respect to the holder main body 101, the third slide piece 108 moves radially inward with respect to the holder main body 101. At this time, the third slide piece 108 pulls back the third movable pin 111 radially inward by the elastic return of the cutting tool body 105a. That is, by this operation, the position of the radially outer end of the tip 105c of the precision finishing bit 105 is moved radially inward.

As shown in FIGS. 1 to 3, the rotation motor 38 is fixed near the upper ends of the draw bars 36 and 37 and on the front side of the spindle head body 31 in FIG. 1. The rotation motor 38 is a motor for rotating the first and second main shafts 32 and 33 simultaneously.
The rotation transmission mechanism 39 includes, for example, gear drive or belt drive. The rotation transmission mechanism 39 transmits the rotational driving force of the rotation motor 38 to the first and second main shafts 32 and 33.

  The first and second protruding motors 40 and 41 are fixed to the upper ends of the spindle head main body 31 and directly above the first and second spindles 32 and 33. These first and second protruding motors 40 and 41 are motors for moving the first and second draw bars 36 and 37 relative to the first and second main shafts 32 and 33 in the axial direction. . That is, the first and second protruding motors 40 and 41 are motors for positioning the radial positions of the chips 103c, 104c, and 105c.

  The first and second protruding mechanisms 42 and 43 are for converting the rotational driving force of the first and second protruding motors 40 and 41 into the axial movement of the draw bars 36 and 37. Specifically, the first and second protruding mechanisms 42 and 43 include a ball screw 301, a ball screw nut 302, and a connecting member 303. The ball screw 301 is connected to the first and second protruding motors 40 and 41 and is provided on the spindle head main body 31 coaxially with the first and second draw bars 36 and 37. The ball screw nut 302 is screwed into the ball screw 301 and is fixed to the connecting member 303. The connecting member 303 connects the ball screw nut 302 and the draw bars 36 and 37. The connecting member 303 is provided between the draw bars 36 and 37 via a rolling bearing. That is, when the first and second protruding motors 40 and 41 are rotated, the ball screw 301 is rotated and the ball screw nut 302 is moved in the axial direction with respect to the spindle head main body 31. As the ball screw nut 302 moves, the connecting member 303 moves in the axial direction with respect to the spindle head main body 31. At this time, since the connecting member 303 is engaged with the draw bars 36 and 37 in the axial direction, the draw bars 36 and 37 move relative to the spindle head body 31 as the connecting member 303 moves in the axial direction with respect to the spindle head body 31. To move in the axial direction.

(Detailed configuration of control device 80)
Next, a detailed configuration of the control device 80 will be described with reference to FIG. FIG. 7 is a block configuration diagram of the control device 80. As shown in FIG. 7, the control device 80 includes a command unit 81, a processing control unit 82, a measurement control unit 83, and a correction unit 84.

  The command unit 81 outputs a command related to machining and measurement of the cylinder block W, which is a workpiece, based on a predetermined program. The machining control unit 82 controls various motors necessary for machining based on the command output from the command unit 81 and the correction command output from the correction unit 84. More specifically, the machining control unit 82 includes the Z-axis feed motor 22 that drives the spindle head 30, the rotation motor 38, the first and second projecting motors 40 and 41, and the X-axis feed of the jig table 50. Control the motor.

  The measurement control unit 83 controls various motors for measuring the cylinder block W that is a workpiece after machining, based on the command output from the command unit 81. Specifically, the measurement command unit 83 controls the Z-axis feed motor that drives the measuring instrument 60 and the X-axis feed motor of the measurement table 70. Further, the measurement control unit 83 causes the measurement device 60 to perform a measurement operation.

  The correction unit 84 inputs the measurement result obtained by the measuring instrument 60. And the correction | amendment part 84 outputs a correction instruction | command to the process control part 82 based on a measurement result. The correction command is a command for correcting the radial position of the first and second intermediate finishing tools 103 and 104 and the radial position of the precision finishing tool 105. Specifically, when the difference between the inner diameter of the bore portion of the cylinder block W after processing measured by the measuring instrument 60 and a reference value is equal to or greater than a predetermined first threshold (for example, 2 μm), the next cylinder When the fine finishing of the block W is performed, the radial position of the fine finishing bit 105 is corrected so that the difference from the reference value becomes zero. After correcting the radial position of the precision finishing bit 105 several times, the radial position of the intermediate finishing bit 103, 104 is corrected.

(Drilling method with boring machine)
Next, a hole drilling method using the above-described boring apparatus will be described with reference to FIGS. FIG. 8 is a flowchart showing a hole drilling method using a boring apparatus. FIG. 9 is a process diagram showing the processing by the processing control unit 82. FIG. 10 is a graph showing the correction process by the correction unit 84 constituting the control device 80, and showing the relationship of the correction amount accumulated value to the number of fine finishing corrections.

  As shown in FIG. 8, the cylinder block W, which is a workpiece carried into the boring apparatus, is processed (machining process: S1). In this processing, as shown in FIG. 9, first, the jig table 50 that clamps the cylinder block W is positioned at a predetermined position. At this time, the draw bars 36 and 37 are moved downward in the axial direction (S11). Along with this operation, the intermediate finishing tools 103 and 104 move radially outward, and the fine finishing tool 105 moves radially inward. At this time, the most projecting tip radially outward is the tip of the roughing cutting tool 102, and the next tip projecting radially outward is the tip 103c of the intermediate finishing tool 103, 104. The tip that is 104c and located most inward in the radial direction is the tip 105c of the precision finishing bit 105. Here, when a correction command for the intermediate finishing bit 103, 104 is output by a correction process described later, the draw bars 36, 37 are positioned at the axial position corresponding to the correction amount. That is, the positions of the radially outer ends of the chips 103c and 104c of the intermediate finishing tools 103 and 104 are corrected.

Subsequently, while rotating the tool holders 34 and 35 around the axis, the tool holders 34 and 35 are lowered by rapid traverse to approach the workpiece W (S12).
Subsequently, the tool holders 34 and 35 are inserted into the bore portions of the first cylinder and the third cylinder of the cylinder block W, respectively (S13). At this time, the chip 102c of the roughing cutting tool 102 is positioned slightly lower in the axial direction than the chips 103c, 104c of the intermediate finishing tool 103, 104. Therefore, the bore portion into which the tool holders 34 and 35 are inserted is subjected to rough machining by the chip 102 of the roughing cutting tool 102, and immediately after that, the intermediate finishing process is performed by the chips 103c and 104c of the semi-finishing cutting tool 103 and 104. Done.

  Subsequently, after all the chips 102c to 105c have popped out from the lower end opening of the bore portion, the draw bars 36 and 37 are pulled up (S14). With this operation, the intermediate finishing tools 103 and 104 move radially inward, and the fine finishing tool 105 moves radially outward. At this time, the tip that protrudes most outward in the radial direction is the tip 105c of the precision finishing bit 105, and the next tip that protrudes radially outward is the tip 102c of the roughing bit 102. The chips positioned radially inward are the chips 103c and 104c of the intermediate finishing tools 103 and 104, respectively. Here, when a correction command for the precision finishing bit 105 is output by a correction process described later, the draw bars 36 and 37 are positioned at axial positions corresponding to the correction amount. That is, the position of the radially outer end of the tip 105c of the precision finishing bit 105 is corrected.

Subsequently, the tool holders 34 and 35 inserted in the bore portions of the first cylinder and the third cylinder of the cylinder block W are respectively lifted (S15). At this time, the fine finishing of the bore portion is performed by the tip 105c of the precision finishing bit 105 protruding most outward in the radial direction.
Subsequently, after all of the chips 102c to 105c have popped out from the upper end opening of the bore portion, the tool holders 34 and 35 are raised by rapid return while maintaining the state where the tool holders 34 and 35 are rotated around the axis. Separate (S16).

Subsequently, the draw bars 36 and 37 are pushed down (S17). With this operation, the intermediate finishing tools 103 and 104 move radially outward, and the fine finishing tool 105 moves radially inward. At this time, the draw bars 36 and 37 are positioned in consideration of the correction amount of the intermediate finishing bits 103 and 104 by the correction process.
At the same time, the jig table 50 is moved so that the bores of the second cylinder and the fourth cylinder of the cylinder block W are positioned directly below the tool holders 34 and 35 (S17).

Subsequently, the tool holders 34 and 35 are lowered by rapid traverse to approach the workpiece W (S18).
Subsequently, tool holders 34 and 35 are inserted into the bores of the second cylinder and the fourth cylinder of the cylinder block W, respectively (S19). This is the same processing as step S13 described above. In other words, the bores of the second and fourth cylinders are roughed by the chip 102c of the roughing cutting tool 102, and immediately after that, the intermediate finishing process is performed by the chips 103c and 104c of the half finishing cutting tools 103 and 104. Is called.

  Subsequently, after all the chips 102c to 105c have popped out from the lower end opening of the bore portion, the draw bars 36 and 37 are pulled up (S20). With this operation, the intermediate finishing tools 103 and 104 move radially inward, and the fine finishing tool 105 moves radially outward. At this time, the draw bars 36 and 37 are positioned in consideration of the correction amount of the precision finishing bit 105 by the correction process.

Subsequently, the tool holders 34 and 35 inserted in the bores of the second cylinder and the fourth cylinder of the cylinder block W are respectively lifted (S21). At this time, the fine finishing of the bore portion is performed by the tip 105c of the precision finishing bit 105 protruding most outward in the radial direction.
Subsequently, after all of the chips 102c to 105c have popped out from the upper end opening of the bore portion, the tool holders 34 and 35 are raised by rapid return while maintaining the state where the tool holders 34 and 35 are rotated around the axis. Separate (S22). Then, the cylinder block W that has been processed is unloaded to the measurement table 70 of the measuring instrument 60, and the cylinder block W that has been loaded next is processed.

  Returning to FIG. When the processing of the cylinder block W is completed, measurement processing by the measuring instrument 60 is subsequently performed (S2). The measuring instrument 60 measures the inner diameters of the bore portions of the second cylinder and the fourth cylinder of the cylinder block W that have been finished up to the fine finishing process.

  When the measurement process is completed, a correction process is performed next when processing the cylinder block W (S3). Specifically, the cutting tools 103 to 105 of the first tool holder 34 are corrected based on the measurement result of the bore portion of the second cylinder, and the second tool holder 35 of the second tool holder 35 is corrected based on the measurement result of the bore portion of the fourth cylinder. Each byte 103 to 105 is corrected. Further details of each correction process will be described with reference to FIG. Here, the predetermined first threshold value for correcting the fine finishing bit 105 will be described as 2 μm.

  First, it is assumed that the difference between the measurement result by the measuring instrument 60 and the reference value is 2 μm in the state where the machining of the plurality of cylinder blocks W is completed. In this case, since the difference is not less than the predetermined first threshold value (2 μm), when performing fine finishing (S15 and S21 in FIG. 9), the radial position of the fine finishing bit 105 is set to a difference of 2 μm. Move radially outward (first fine finish correction). Fine finishing correction second time: 3 μm, fine finishing correction third time: 3 μm. At this time, the correction amount cumulative value of the precision finishing bit 105 is 8 μm.

  Here, the intermediate finishing tools 103 and 104 are corrected in accordance with the intermediate finishing of the next cylinder block W when the accumulated correction amount of the precision finishing tool 105 becomes equal to or greater than a predetermined second threshold (for example, 10 μm). At the time of processing (S13 and S19 in FIG. 9), 5 μm correction is performed so that the radial position of the intermediate finishing tools 103 and 104 approaches the reference value. However, the correction of the radial position of the intermediate finishing tools 103 and 104 is not performed so that the difference from the reference value becomes zero, but is always corrected so that the difference from the reference value becomes positive. Here, when the correction amount accumulated value of the fine finishing bit 105 becomes 10 μm or more, the intermediate finishing bit 103, 104 is corrected so as to approach the reference value side by 5 μm.

  In the third fine finishing correction, since the correction amount accumulated value of the fine finishing bit 105 has not yet reached 10 μm, the correction of the intermediate finishing bits 103 and 104 is not performed at this point. Thereafter, in the fourth correction of the fine finishing bit 105, the correction amount of the fine finishing bit 105 is 3 μm, so that the correction amount cumulative value is 11 μm. That is, the correction amount accumulated value of the precision finishing bit 105 is 10 μm or more. At this time, when performing the next intermediate finishing, the radial positions of the intermediate finishing tools 103 and 104 are moved outward in the radial direction by 5 μm.

  In some cases, the correction of the precision finishing bit 105 may be a negative correction as shown in the fifth correction. This reason is considered to be influenced by, for example, measurement variations. Since the correction of the intermediate finishing tools 103 and 104 is based on the correction amount accumulated value of the precision finishing tool 105, the negative correction is counted as negative.

  As described above, the fine finishing bit 105 is corrected in a fine correction, so that even if the tip 105c of the fine finishing bit 105 is worn, the processing accuracy after the fine finishing is closer to the reference value. can do. On the other hand, the correction of the intermediate finishing tools 103 and 104 is less frequent than the precision finishing tool 105. Furthermore, the correction amount of the intermediate finishing tools 103 and 104 is smaller than the difference between the measured value after the fine finishing and the reference value.

  This is because the correction of the intermediate finishing tools 103 and 104 is not performed based on the result of measuring the workpiece W after the intermediate finishing process, but based on the correction amount accumulated value of the precision finishing tool 105. Yes. In other words, the intermediate finishing bits 103 and 104 are corrected after the correction amounts of the intermediate finishing bits 103 and 104 are estimated indirectly. Thus, since the correction amount is indirect, the correction of the intermediate finishing bits 103 and 104 cannot be said to have high accuracy.

  Furthermore, in order to improve the processing accuracy after fine finishing, it is necessary that the processing diameter by the intermediate finishing bit 103, 104 does not become larger than the processing diameter by the fine finishing bit 105. Therefore, as described above, the intermediate finishing tools 103 and 104 are corrected.

  According to the boring apparatus of this embodiment described above, the following effects are obtained. Two types of cutting tools 103 and 104 for intermediate finishing and a cutting tool 105 for fine finishing are movable in the radial direction with respect to the holder body 101. Accordingly, when the chips 103c, 104c of the intermediate finishing bit 103, 104 are worn, the radial position of the intermediate finishing bit 103, 104 is corrected, and when the tip 105c of the fine finishing bit 105 is worn. The radial position of the precision finishing bit 105 can be corrected. Therefore, the change in the machining allowance by the tip 105c of the fine finishing tool 105 in the fine finishing process can be suppressed as compared with the conventional case. Thereby, the life of the chip 105c of the precision finishing bit 105 can be improved.

  Further, it is possible to prevent the machining allowance of the intermediate finishing tool 103, 104 by the chips 103c, 104c from being changed by the workpiece W, and the machining allowance of the precision finishing tool 105 by the tip 105c is changed by the workpiece W. Can be suppressed. Therefore, the chips 103c and 104c of the intermediate finishing bit 103 and 104 and the chip 105c of the fine finishing bit 105 can be set to have almost the same lifetime. That is, since the replacement of the chips 103c and 104c of the intermediate finishing tool 103 and 104 and the replacement of the chip 105c of the precision finishing tool 105 can be performed at the same time, the facility stop time can be shortened.

  Further, the workpiece W is measured only after the fine finishing machining step which is the final step, and the radial positions of the intermediate finishing bits 103 and 104 and the fine finishing bit 105 are corrected based on the measurement result. That is, the radial positions of the intermediate finishing tools 103 and 104 and the fine finishing tool 105 are corrected by one measurement. Thereby, it is not necessary to increase the number of times of measurement compared to the conventional case. Therefore, it is possible to prevent the cycle time from being prolonged.

  Here, based on the result measured after the fine finishing process, the intermediate finishing tools 103 and 104 in the intermediate finishing process are corrected. However, since the wear amount of the chips 103c and 104c of the intermediate finishing bit 103, 104 is substantially proportional to the wear amount of the tip 105c of the fine finishing bit 105, the wear amount of the tip 105c of the fine finishing bit 105 is measured. If possible, the wear amount of the chips 103c, 104c of the intermediate finishing tools 103, 104 can be estimated to some extent. Therefore, sufficient accuracy can be obtained by correcting the radial positions of the intermediate finishing tools 103 and 104 based on the measurement after the fine finishing process.

  Further, the accumulated correction value of the radial position of the intermediate finishing bit 103, 104 is determined based on the accumulated correction value of the radial position of the precision finishing bit 105. As a result, the correction amount cumulative value of the radial position of the intermediate finishing tools 103 and 104 can be set to a sufficiently appropriate value. As described above, the amount of wear of the tips 103c and 104c of the intermediate finishing bit 103 and 104 and the amount of wear of the tip 105c of the fine finishing bit 105 are substantially proportional. The wear amount of the tip 105c of the fine finishing bit 105 substantially corresponds to the correction amount accumulated value of the radial position of the fine finishing bit 105. That is, since the accumulated correction amount value of the radial position of the intermediate finishing bit 103, 104 is determined after referring to the correction amount accumulated value of the radial position of the fine finishing bit 105, the intermediate finishing bit 103 is determined. , 104 without directly measuring the wear amount of the chips 103c, 104c, it is possible to determine a cumulative correction amount value of the radial position of the finishing tools 103, 104 with sufficient accuracy.

  Further, the correction amount cumulative value of the radial finishing position of the intermediate finishing tool 103, 104 is set to be smaller than the correction amount cumulative value of the radial finishing position of the precision finishing tool 105. Thereby, it is possible to prevent the chips 103c and 104c of the intermediate finishing tool 103 and 104 from being processed beyond the processing diameter to be processed by the chip 105c of the precision finishing tool 105. Thereby, it can prevent taking out the workpiece W of inferior goods.

<Second embodiment>
Next, the boring apparatus according to the second embodiment will be described. In the boring apparatus of the first embodiment, the roughing cutting tool 102 is fixed to the holder body 101. In the second embodiment, the roughing cutting tool 102 is configured to be movable in the radial direction with respect to the holder main body 101, similarly to the intermediate finishing tool 103.

  In this case, the rough machining tool 102 in the first embodiment, the structure of the holder body 101 near the roughing tool 102, and the structure of the draw bars 36 and 37 in the vicinity of the roughing tool 102 are the same as in the first embodiment. The configuration is changed to that corresponding to the intermediate finishing bit 103. That is, when the draw bars 36 and 37 are pulled up from the upper side to the lower side, the roughing cutting tool 102 moves outward in the radial direction in the same manner as the intermediate finishing tools 103 and 104. On the contrary, when the draw bars 36 and 37 are pushed down from the lower side to the upper side, the roughing cutting tool 102 moves inward in the radial direction in the same manner as the intermediate finishing tools 103 and 104. Thereby, the lifetime of the chips 103c and 104c of the intermediate finishing bit 103 and 104 can be improved.

<Third embodiment>
In the boring apparatus according to the first embodiment, the bores of the second and fourth cylinders of the cylinder block W are measured by the measuring instrument 60 by moving the measurement table 70 in the X-axis direction. did. Then, the correction unit 84 corrects each bite 103 to 105 of the first tool holder 34 based on the measurement result of the bore portion of the second cylinder, which is the rear part of the part processed by the first tool holder 34. did. On the other hand, the correction unit 84 corrects each bite 103 to 105 of the second tool holder 35 based on the measurement result of the bore portion of the fourth cylinder, which is the rear part of the part processed by the second tool holder 35. did.

  On the other hand, in the third embodiment, the measuring instrument 60 measures the inner diameter of only the second cylinder of the cylinder block W, and the correction unit 84 is based on the measurement result, and the first and second tool holders 34, 35. These bytes 103 to 105 may be corrected. In this case, since it is not necessary to move the position of the cylinder block W in the X-axis direction with respect to the measuring instrument 60, the measurement table 70 becomes unnecessary. Therefore, the apparatus can be simplified. Furthermore, since the time for moving the measurement table 70 can be eliminated, cycle time can be shortened. However, as in the first embodiment described above, it is possible to perform machining with higher accuracy by measuring and correcting each portion machined by the tool holder of each tool holder.

It is a front view of the boring apparatus of this embodiment. It is a right view of the boring apparatus according to the present embodiment. It is an AA expanded sectional view of FIG. It is BB expanded sectional drawing of FIG. It is a figure of the state which turned CC sectional drawing of FIG. 4 clockwise by 90 degrees. It is DD sectional drawing of FIG. It is a block block diagram of the control apparatus 80 of this embodiment. It is a flowchart which shows the hole drilling method using the boring apparatus of this embodiment. FIG. 6 is a process diagram showing a processing process by a processing control unit 82. It is a graph which shows the correction process by the correction | amendment part 84 which comprises the control apparatus 80, and shows the relationship of the corrected amount accumulated value with respect to the number of fine finishing corrections.

Explanation of symbols

10: Bed 20: Column 21: Column body 21a: Guide rail 22: Z-axis feed motor 30: Spindle head 31: Spindle head body 31a: Through holes 32, 33: First and second spindles 34, 35: first and second tool holders 36, 37: first and second draw bars, 38: rotation motor, 39: rotation transmission mechanism 40, 41: first and second protrusion motors, 42 43: First and second protruding mechanisms 50: Jig table, 60: Measuring instrument, 70: Measuring table 80: Control device 81: Command unit, 82: Processing control unit, 83: Measurement control unit, 84: Correction part 101: Holder body 102: Roughing tool 103, 104: First and second intermediate finishing tool 105: Fine finishing tool 106-108: First to third slide pieces 109-111 : First to third Movable pins 112: rotation restricting pins, 113: caps 101a to 101d: notches, 101e to 101h: through holes 102a, 103a, 104a, 105a: bite bodies 102b, 103b, 104b, 105b: mounting bolts 102c, 103c, 104c 105c: Chips 103d, 104d, 105d: Flexible portion 201: Key groove 202, 203: First and second reduced diameter tapered grooves 204: Expanded tapered grooves

Claims (6)

A tool holder having a cutting tool provided on the outer peripheral surface of the holder body, and machining the hole in the workpiece by feeding the tool holder in the axial direction relative to the workpiece while rotating about the axis. In the boring machine,
The holder body;
A first tool provided on an outer peripheral surface of the holder body, provided so as to be movable in a radial direction of the holder body with respect to the holder body, and machining a hole of the workpiece in a first machining step When,
Provided on the outer peripheral surface of the holder body, provided so as to be movable in the radial direction of the holder body with respect to the holder body, and in a second machining step performed after the first machining step, A second bit to machine the hole,
Measuring means for measuring a hole in the workpiece after the second machining step;
When machining the next hole of the workpiece, based on the measurement result by the measuring means, the radial position of the first bite in the first machining step and the second in the second machining step Correction means for correcting the radial position of each tool,
A boring apparatus characterized by comprising: In claim 1,
The boring apparatus according to claim 1, wherein the correction means determines a cumulative correction amount value of the radial position of the first bit based on a correction amount cumulative value of the radial position of the second bit. In claim 2,
The boring apparatus according to claim 1, wherein the correction means sets a correction amount cumulative value of the radial position of the first cutting tool to be smaller than a correction amount cumulative value of the radial position of the second cutting tool. In any one of Claims 1-3,
The machining process of the hole of the workpiece includes a precision finishing process for precisely finishing the hole of the workpiece, and a medium finishing process performed immediately before the precision finishing process,
The first processing step is the intermediate finishing processing step,
The boring apparatus characterized in that the second machining process is the fine finishing process. In any one of Claims 1-3,
The hole processing step of the workpiece is performed immediately before the precision finishing processing step for precisely finishing the hole of the workpiece, the intermediate finishing processing step performed immediately before the precision finishing processing step, and the intermediate finishing processing step. Including roughing process,
The first processing step is the intermediate finishing step and the roughing step,
The second processing step is the fine finishing processing step,
The first cutting tool includes a medium finishing tool that processes a hole in the workpiece in the intermediate finishing process, and a roughing tool that processes a hole in the workpiece in the roughing process. Boring machine. Using a tool holder having a cutting tool provided on the outer peripheral surface of the holder body, the hole of the workpiece is machined by feeding the tool holder in the axial direction relative to the workpiece while rotating the tool holder around the axis. In the hole drilling method,
A first machining step of machining a hole in the workpiece by a first bit provided on an outer peripheral surface of the holder main body and movable relative to the holder main body in a radial direction of the holder main body; ,
The hole of the workpiece is machined after the first machining step by a second bit provided on the outer peripheral surface of the holder main body and movable relative to the holder main body in the radial direction of the holder main body. A second processing step to perform,
A measuring step of measuring the hole of the workpiece by a measuring means after the second machining step;
With
In the first machining step, when machining the next hole of the workpiece, the radial position of the first bit is corrected based on the measurement result by the measuring means to form the hole of the workpiece. Processed
In the second machining step, when machining the hole of the next workpiece, the radial position of the second tool is corrected based on the measurement result by the measuring means, and the hole of the workpiece is corrected. A hole machining method characterized by machining.

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