JP5350104B2 - Internal diameter machining method and apparatus for workpiece - Google Patents

Description

  The present invention relates to an inner diameter machining method and apparatus for machining an inner diameter of a hole formed in a workpiece using a piezoelectric element or the like.

  As a work processing method using a piezoelectric element, a tape running surface for running a magnetic tape on the outer peripheral surface of the fixed drum by moving a bite in the radial direction of the fixed drum using expansion and contraction of a piezoelectric element. A method of processing is disclosed. This document also describes that the piezo element arranged in parallel with the cutting tool protrudes toward the fixed drum from the cutting tool.

Japanese Patent Laid-Open No. 10-15713

  When machining the hole formed in the workpiece using the method of Patent Document 1, the piezo element protrudes from the bite, so that the piezo element hits the inner surface of the hole and may not be machined. . In order to solve this problem, it is possible to arrange the cutting tool inside the hole and the piezoelectric element outside the hole. In this case, depending on the shape of the hole (depth of the hole) Therefore, it is necessary to adjust the distance between the piezo element and the cutting tool, which complicates the apparatus.

  In Patent Document 1, it is necessary to process the outer peripheral surface of a portion of the fixed drum that is not the tape running surface as a reference in order to reliably run the magnetic tape on the tape running surface. Therefore, the outer surface shape of the fixed drum must be processed into a highly accurate circular shape in advance. When machining a hole formed in a workpiece using such a machining method, the inner diameter shape of the hole needs to be machined in advance into a highly accurate circular shape. There is also a problem that the cycle time is increased in a boring step for forming holes.

  Therefore, an object of the present invention is to provide a workpiece inner diameter machining method and apparatus that enable highly accurate inner diameter machining with a simple configuration.

A workpiece inner diameter machining method according to the present invention is a workpiece inner diameter machining method for machining a hole formed in a workpiece with an inner diameter, wherein a cutting tool is disposed between a piezoelectric element or a giant magnetostrictive material and the workpiece, and a rotating means. the workpiece while rotating and while advancing and retracting the cutting tool in the radial direction of the hole in the piezoelectric element or the giant magnetostrictive material, by relatively moving in the depth direction of the hole in the bore A machining step for machining an inner diameter , and a measurement step for measuring inner diameter shape data of a workpiece model that has already been machined, and performing frequency analysis based on the inner diameter shape data measured in the measurement step to The deformation is reproduced, and the voltage applied to the piezoelectric element or the magnetic field applied to the giant magnetostrictive material is controlled so that the cutting tool moves forward and backward based on the reproduced shape of the work model. It characterized that you control at part.

According to the inner diameter machining method for a workpiece according to the present invention , the cutting tool is disposed between the workpiece and a piezoelectric element or a giant magnetostrictive material (hereinafter sometimes referred to as a piezoelectric element or the like). There is no contact with the inner diameter surface of the hole. Therefore, it is not necessary to adjust the positions of the cutting tool and the piezoelectric element according to the shape of the hole. Further, since the expansion / contraction of the piezoelectric element or the like is used as means for moving the blade forward / backward, the responsiveness of the forward / backward movement of the blade is improved as compared with the case where a cam mechanism or the like is used as the means for moving the blade forward / backward. Therefore, it is possible to perform highly accurate inner diameter processing with a simple configuration.

Also , since the inner diameter of the hole formed in the workpiece is processed based on the inner diameter shape of the workpiece model measured in the measurement step, the amount of advancement / retraction of the cutting tool is set based on the rotation axis of the workpiece passing through the center of the hole can do. Thereby, since it is not necessary to set the advance / retreat amount of the cutting tool with reference to the inner diameter surface of the workpiece, in the boring step of forming a hole in the workpiece, which is a process prior to the inner diameter machining step, the inner shape of the hole is changed. The hole formed in the workpiece can be machined into the inner diameter shape of the workpiece model without using a precise circular shape. Therefore, an increase in the cycle time of the boring process can be suppressed.

In the present invention , the workpiece may be a cylinder block .

  Normally, the bore of the cylinder block is processed so as to have a perfect circular cross section in a state where the cylinder head is assembled.

In this case , the bore is processed in advance so that the dummy head imitating the cylinder head of the product is attached to the cylinder block so as to have a perfect circular cross section, and then the dummy head is removed from the cylinder block to remove the stress. The inner shape of the bore is measured using the bore as a workpiece model. At this time, the bore has a non-circular cross section. And when machining the bore of a new cylinder block, holes are formed in the cylinder block in advance in the boring process, and the formed holes are bored on the basis of the inner surface shape of the bore. Eliminates the need to install and remove dummy heads. Thereby, the cycle time of the bore machining of the cylinder block can be shortened.

An inner diameter machining apparatus for a workpiece according to the present invention is an inner diameter machining apparatus for machining a hole formed in a workpiece, and can be brought into contact with the inner diameter surface of the hole while the workpiece is rotated by a rotating means. A moving tool for moving the cutting tool relative to the workpiece in the depth direction of the hole, a piezoelectric element or a giant magnetostrictive material for moving the cutting tool back and forth in the radial direction of the hole, and an inner diameter. A frequency analysis is performed based on the inner diameter shape data of the machined workpiece model to reproduce the deformation of the workpiece model, and the cutting tool is applied to the piezoelectric element so that the cutting tool is advanced and retracted based on the reproduced shape of the workpiece model. and a control unit for controlling the voltage or the magnetic field applied to the giant magnetostrictive material that, a, especially that the cutting tool is, the piezoelectric element or the is disposed between the super magnetostrictive material and the workpiece To.

Further, in the above-described inner diameter processing apparatus, the holder is disposed in a holder for holding the cutting tool, a head portion provided with the holder, and a chamber formed in the head portion, and presses the holder outward in the radial direction of the hole. An actuator having the piezoelectric element or the giant magnetostrictive material, and a biasing member that is provided on the head portion and biases the holder toward the actuator. The holder includes the chamber and the outside. A communicating through hole may be formed.

Furthermore, in the above inner diameter processing apparatus, the actuator may be formed with a curved surface that contacts the opening of the through hole in the holder.

  According to this invention, since the cutting tool is disposed between the workpiece and the piezoelectric element or the giant magnetostrictive material, the piezoelectric element or the like does not hit the inner diameter surface of the hole, and the cutting tool and the piezoelectric element according to the shape of the hole. It is not necessary to adjust the position of the etc. Therefore, it is possible to perform highly accurate inner diameter processing with a simple configuration.

It is the figure which showed the internal diameter processing apparatus which concerns on this invention, and its peripheral device. It is a partial cross section enlarged view of a processing head and a holder part. It is sectional drawing along the III-III line of FIG. It is a flowchart which shows the procedure which processes the bore | bore of a cylinder block. FIG. 5A is a diagram showing a state in which a bore having a perfectly circular cross section is formed in a model block to which a dummy head is attached, and FIG. 5B is a diagram showing an inner shape of the bore when the dummy head in FIG. 5A is removed. FIG. 5C is a view showing a state in which the cylinder head is attached to a cylinder block having a bore that has been bored by the bore machining apparatus according to the present invention. 6A is a partial cross-sectional view of a model block to which a dummy head is attached, FIG. 6B is a view showing a state where the bore is deformed into an elliptical cross section, and FIG. 6C is a view where the bore is deformed into a quadrangular cross section. FIG. It is the flowchart which showed the procedure of step S4-S7 in the flowchart of FIG. 4 in detail. It is a schematic diagram which shows the internal diameter shape of the bore measured at the measurement point of the model block. It is sectional drawing which shows the internal diameter shape of the bore measured at one measurement point of the model block. It is the figure which expressed the internal diameter shape of the bore measured at one measurement point of the model block with the axis of rotation as the horizontal axis. It is a figure which shows the frequency component which comprises the internal diameter shape of the bore | bore of a model block. It is a figure which shows the state which synthesize | combined and inverted the frequency component which comprises the internal diameter shape of the bore | bore of a model block. FIG. 13A is a diagram showing a processing chip advance / retreat map, and FIG. 13B is a partially enlarged view of FIG. 13A.

  Embodiments according to the present invention will be described below with reference to FIGS.

  First, the inner diameter machining apparatus according to the present embodiment is an apparatus for machining an inner diameter of a hole formed in a workpiece, and is used, for example, to form a bore of a cylinder block of an in-line four-cylinder engine. However, the inner diameter processing apparatus according to this embodiment may be used to form a bore of a cylinder block of a single cylinder engine.

  The inner diameter machining apparatus 10 is used in cooperation with a rotation drive mechanism 300 serving as a rotation unit that rotates the cylinder block 200 serving as a workpiece, an inner surface shape measuring device 400, and a host computer 402.

  The rotation drive mechanism 300 includes a rotation table 302, a chuck 304 that is provided on the rotation table 302 and holds the cylinder block 200, a first motor 306 that rotationally drives the rotation table 302, and the rotation speed and rotation of the rotation table 302. A first rotary encoder 308 for detecting a corner is provided. The first rotary encoder 308 detects an analog current flowing through the first motor 306, converts the detected analog current into an analog voltage, converts the converted analog voltage into a digital voltage, and outputs the digital voltage.

  Before the cylinder block 200 is held by the chuck 304, four holes 202 are formed in series in order to perform inner diameter processing in the boring step (only one hole is shown in FIG. 1). The cylinder block 200 is held by the chuck 304 so that the center of the hole 202 for performing the inner diameter processing is positioned on the rotation axis A of the turntable 302.

  The inner surface shape measuring instrument 400 measures the inner surface shape of the work model. As the work model, the bore 206 of the cylinder block 204 shown in FIG. 5B is used. The bore 206 of the cylinder block 204 shown in FIG. 5B is formed by the following procedure. First, as shown in FIG. 5A, a dummy head 208 is attached to a cylinder block (hereinafter sometimes referred to as a model block) 204 of the same type as the cylinder block 200 that performs inner diameter processing. Next, a bore 206 having a circular cross section is processed (boring and inner diameter processing) in the model block 204 to which the dummy head 208 is attached. Thereafter, by removing the dummy head 208, the bore 206 of the model block 204 is formed. The inner surface shape measuring instrument 400 outputs the measured inner surface shape data of the work model to the host computer 402.

  As shown in FIG. 1, the inner diameter processing apparatus 10 includes a moving mechanism 12 as a moving means, an apparatus main body 14, and a control unit 16.

  The moving mechanism 12 is for moving the apparatus main body 14 in the depth direction of the hole of the cylinder block 200 (X direction in FIG. 1), and is configured as a feed screw mechanism. Further, the moving mechanism 12 includes a shaft portion 18 extending in one direction and having a screw formed on the outer periphery, a nut portion 20 screwed into the shaft portion 18, and an end portion of the shaft portion 18. A second motor 22 that rotates the shaft 18 and a second rotary encoder 24 that detects the rotation speed and rotation angle of the shaft portion 18 are provided. Similar to the first rotary encoder 308, the second rotary encoder 24 converts an analog current flowing through the second motor 22 into a digital voltage and outputs the digital voltage.

  In the apparatus main body 14, a support portion 26 to which the nut portion 20 is connected, a holder portion 28 provided on the support portion 26 and extending in the axial direction of the shaft portion 18, and a machining head inserted into the hole 202 of the cylinder block 200. 30 is provided.

  As shown in FIGS. 2 and 3, the machining head 30 includes a head portion 32 connected to the end of the holder portion 28, and a machining tip 34 as a cutting tool that contacts the inner diameter surface of the hole 202 of the cylinder block 200. A chip holder 36 for holding the machining chip 34 and a biasing mechanism 38 for biasing the chip holder 36 are provided.

  The head unit 32 includes an actuator chamber 40 formed in the head unit 32 and a piezoelectric actuator 42 as a piezoelectric element disposed so that a gap is formed in the actuator chamber 40.

  The piezo actuator 42 is for advancing and retracting the machining chip 34, and a piezo element (not shown) that expands and contracts in one direction (Y direction in FIG. 2) when a voltage is applied through the electric wire 44 in the expansion and contraction direction. A plurality of actuator main bodies 46 are arranged, and a protrusion 48 protrudes from one end surface of the actuator main body 46 in the expansion / contraction direction. The number of piezoelectric elements may be arbitrarily set according to the degree of unevenness of the inner shape of the work model. This is because the advance / retreat width of the machining tip 34 can be adjusted by the number of piezoelectric elements. The actuator main body 46 is fixed to the head portion 32 with a bolt 50 in a state where the other end surface in the expansion / contraction direction is in contact with the wall surface of the actuator chamber 40. The protrusion 48 has a curved surface 52 that contacts the chip holder 36. Further, the piezo actuator 42 outputs a digital voltage to the electric wire 54 in accordance with the displacement of the actuator body 46. The electric wires 44 and 54 are connected to the control unit 16.

  The actuator chamber 40 is formed on the tip side from the center of the head portion 32. As a result, as shown in FIG. 1, the piezo actuator 42, the chip holder 36, and the machining chip 34 are positioned on the tip side from the center of the head portion 32, so that the rotary table 302 and the cylinder block 200 of the rotary drive mechanism 300 Can be narrowed. Thereby, the cylinder block 200 can be held and rotated at a position close to the turntable 302 by the chuck 304, so that the rotation of the cylinder block 200 can be stabilized.

  As shown in FIG. 2, the tip holder 36 is urged toward the piezo actuator 42 by the urging mechanism 38. As a result, the tip holder 36 can advance and retreat in the radial direction of the hole 202 of the cylinder block 200 (Y direction in FIG. 2). As shown in FIG. 3, a through hole 56 is formed in the chip holder 36. Thereby, since the actuator chamber 40 communicates with the outside, even when the piezo actuator 42 generates heat due to expansion and contraction of the piezo element, the heat can be released to the outside. Furthermore, since the curved surface 52 of the protrusion 48 is received by the opening of the through hole 56, the advance / retreat of the piezo actuator 42 can be accurately transmitted to the machining chip 34. As shown in FIG. 1, the machining tip 34 is located between the piezo actuator 42 and the cylinder block 200.

  As shown in FIG. 2, the urging mechanism 38 includes a cartridge 60 fixed to the head portion 32 by bolts 58 and 58, and an urging force provided on the cartridge 60 to urge the chip holder 36 toward the piezo actuator 42. A member 62 is provided. For example, a spring member or the like may be used as the urging member 62.

  Next, the advancing / retreating operation of the machining tip 34 will be briefly described. When the control unit 16 applies a voltage to the actuator main body 46 through the electric wire 44, the plurality of piezoelectric elements extend in proportion to the magnitude of the applied voltage, so that the actuator main body 46 extends toward the chip holder 36 side. At this time, the actuator body 46 presses the chip holder 36 via the curved surface 52 of the protrusion 48 against the urging force from the urging member 62 generated in the chip holder 36. As a result, the machining tip 34 moves from the initial position to the outside in the radial direction of the hole 202 of the cylinder block 200. The initial position of the processing chip 34 may be set so that the position of the tip of the processing chip 34 matches the position of the outer surface of the cartridge 60 with respect to the radial direction of the hole 202 of the cylinder block 200, for example.

  Further, when the control unit 16 increases the voltage applied to the actuator body 46 through the electric wire 44, the machining tip 34 moves to the outside in the radial direction of the hole 202 of the cylinder block 200 from the position before the voltage is increased.

  On the other hand, when the control unit 16 reduces the voltage applied to the actuator body 46 through the electric wire 44, the plurality of piezoelectric elements are contracted, and thus the actuator body 46 is contracted to the bolt 50 side. At this time, the tip holder 36 is pressed by the urging member 62 in a state where the pressing force from the actuator body 46 is reduced. As a result, the machining tip 34 moves inward in the radial direction of the hole 202 of the cylinder block 200 from the position before the voltage is reduced.

  Further, when the control unit 16 stops the voltage applied to the actuator body 46 via the electric wire 44, the machining tip 34 returns to the initial position.

  As shown in FIG. 1, the control unit 16 is provided with a main control device 64, a synchronization controller 66, a first servo amplifier 68, a second servo amplifier 70, and a piezo driver 72.

  The main control device 64 drives the first motor 306 via the first servo amplifier 68 and the second motor 22 via the second servo amplifier 70 according to the output from the host computer 402, and rotates the turntable 302. The position of the machining tip 34 with respect to the speed and the X direction is controlled. That is, the main control device 64 is a device that operates in the same manner as a so-called NC (numerical value) control device.

  The synchronous controller 66 outputs a command signal to the piezo driver 72 with reference to the machining tip advance / retreat map based on the rotation angle of the turntable 302 (cylinder block 200) and the position of the machining tip with respect to the X direction. Applies a voltage to the piezo actuator 42 in accordance with the command signal, thereby controlling the advance / retreat of the machining tip 34. The machining chip advance / retreat map is for controlling the position of the machining chip 34 with respect to the Y direction when the rotation axis A of the turntable 302 is used as a reference. Specifically, the machining tip advance / retreat map indicates the position of the machining tip 34 with respect to the Y direction with respect to the rotation angle of the cylinder block 200 and the rotation axis A of the turntable 302 for each position of the machining tip 34 with respect to the X direction. Are obtained in the direction of the axis of rotation A (see FIG. 13A), and are generated by the host computer 402 and stored in the synchronization controller 66. The rotation angle and rotation speed of the cylinder block 200 are obtained from the number of pulses per unit time of the digital voltage acquired with reference to the output signal from the first rotary encoder 308, that is, the number of pulses of the sampling time. Further, the position of the machining tip 34 with respect to the X direction is obtained from the number of pulses per unit time of the digital voltage obtained by referring to the output signal from the second rotary encoder 24, that is, the number of pulses of the sampling time.

  The piezo driver 72 performs feedback control by referring to the output signal from the piezo actuator 42 so that the displacement amount of the piezo actuator 42 matches the advance / retreat amount of the machining chip 34 instructed from the synchronous controller 66.

  Next, the procedure for machining the bore of the cylinder block will be described with reference to the flowchart of FIG.

  First, in step S1, as shown in FIG. 5A, a dummy head 208 is attached to a model block 204, which is a cylinder block material, by a plurality of bolts 210... 210 (only two are shown in the figure). The dummy head 208 is made of a shape and material simulating a product cylinder head, and a hole 212 into which a machining head of a boring machine (not shown) can be inserted is formed in the center.

  Next, in step S2, the model block 204 is arranged at a predetermined position, and a bore 206 having a desired roundness is processed in the model block 204 by a boring apparatus.

  Next, in step S3, tightening of the plurality of bolts 210... 210 is released from the model block 204, and the dummy head 208 is removed. Then, as shown in FIG. 5B, the inner diameter of the bore 206 of the model block 204 is slightly deformed from the state of FIG. 5A. This is because the stress due to the assembly of the dummy head 208 is released.

  Specifically, as shown in FIG. 6A, the model block 204 has four bores 206 arranged in a straight line. Around each bore 206, a plurality of bolt holes 214... 214 to which a plurality of bolts are screwed are formed. As shown in FIGS. 5 and 6, when the dummy head 208 is removed from the model block 204, the pressing force by the dummy head 208 is removed, so that the inner diameter shape of the bore 206 on the dummy head 208 side is deformed into an elliptical shape. (See FIG. 6B). Also, since the stress acting between the screw thread of the bolt holes 214... 214 and the screw thread of the bolt is removed, the inner diameter shape of the bore 206 on the side opposite to the dummy head 208 (crankshaft side) is shown in FIG. As shown, it transforms into a square.

  Therefore, hereinafter, in the step of analyzing the frequency of the inner diameter shape of the bore 206, an example of performing frequency analysis up to the fourth order is described. This is because the deformation of the bore 206 of the model block 204 can be almost reproduced by frequency analysis up to the fourth order. That is, the quaternary component represents a quadrilateral component, the tertiary component represents a triangular component, and the secondary component represents an elliptical component. Therefore, the cosine wave is obtained by performing frequency analysis from the 0th to the 4th order. By synthesizing these cosine waves, the deformation of the bore 206 of the model block 204 can be reproduced, and higher-order noise can be removed.

If the two-dimensional cross section (X _I , Y _I ) is stored as a point cloud (X _I , Y _I ) in the normal NC data format, the amount of data becomes enormous. By storing data in a data format, the amount of data can be considerably reduced, and data processing can be speeded up. In other words, in order to form a hole with a non-circular cross section so as to eliminate the deformation of the bore when the cylinder head is assembled to the cylinder block, frequency analysis from the 0th order to the 4th order may be performed. Less amount is required. In the present embodiment, an example up to the fourth-order frequency analysis is shown, but it may be 50th, 100th, or higher order depending on the shape of the hole. For example, when expressing one round of the shape of a hole with a non-circular cross section in the normal NC data format every 1 °, 720 parameters are required, but when expressing in the 50th order curve data format , 101 parameters are sufficient. That is, the radius error (0th order), 50 nth order amplitudes, and 50 nth order phases. As described above, even if frequency analysis up to the 50th order is executed, the amount of data can be reduced and the data processing can be speeded up by storing in the curve data format.

  Therefore, in step S4, the inner diameter shape is measured at predetermined intervals in the depth direction of the bore 206 in the bore 206 of the model block 204 after the dummy head 208 is removed, and stored in the upper computer 402 as inner diameter shape data.

  In step S5, frequency analysis is performed based on the inner diameter shape data, and an analysis inner diameter shape parameter is calculated.

  Next, in step S <b> 6, a machining tip advance / retreat map is generated by the host computer 402 based on the calculated analysis inner diameter shape parameter and stored in the synchronous controller 66 of the inner diameter processing apparatus 10.

  In step S7, first, a cylinder block 200, which is a new cylinder block material different from the model block 204, is arranged at a predetermined position. Next, after boring the cylinder block 200, the inner diameter machining based on the stored machining tip advance / retreat map is applied to the hole 202 of the cylinder block 200 under the control of the synchronous controller 66.

  In step S8, as shown in FIG. 5C, unlike the dummy head 208, a cylinder head 216 used as an actual product is prepared, and the cylinder head 216 is attached to the cylinder block 200 on which the inner diameter processing is performed. 218 is attached. Then, the inner diameter shape of the hole (bore) 202 of the cylinder block 200 has the same roundness as the bore 206 of the model block 204.

  Next, a detailed procedure from the measurement of the bore inner diameter shape in step S4 to the inner diameter machining in step S7 will be described with reference to the flowchart of FIG.

  In step S11 (S4), for example, as shown in FIG. 8, four measurement points M1 to M4 are set at predetermined intervals in the depth direction of the bore 206 by the inner surface shape measuring device 400 for all cylinders. The inner diameter shape of the bore 206 at the measurement points M1 to M4 is measured.

  Specifically, for all cylinders, sensors such as an air microsensor, a proximity sensor, and a laser sensor are inserted into the bore 206, moved in the depth direction of the bore 206 while rotating, and the bore 206 at each measurement point is measured. The inner diameter shape is measured and used as inner diameter shape data. In addition, although the example measured at predetermined intervals is shown, even if it is measured at non-equal intervals, for example, several points on the cylinder head side of the model block 204, or conversely, several points on the crankshaft side of the model block 204 are measured. Good. In FIG. 8, the inner diameter shapes R1 to R4 of the bore 206 at the respective measurement points M1 to M4 are different from each other and have a non-circular shape such as an ellipse, a triangle, a quadrangle, or an eccentric perfect circle. .

  As shown in FIGS. 9 and 10, it can be seen that the measured inner diameter shape of the bore 206 has irregularities of about ΔL and further includes high-order noise. 9 and 10, the position of the inner peripheral surface of the bore 206 when the deformation amount of the bore 206 is zero is set as a reference line L0, and the inner side of the reference line L0 by ΔL is set as L1, and the reference line L0 is set. The outer side is set to L2 by ΔL.

In step S12, the host computer 402 performs frequency analysis on the inner diameter shape of the bore 206 at each of the measurement points M1 to M4, thereby extracting an n-order component of an error with respect to a perfect circle, obtaining each amplitude and phase, Generate analysis inner diameter shape parameters (A _n , P _n ) for the phase.

Specifically, the amount of protrusion from the reference line L0 is represented by a function x (θ) of the angle θ according to the following formulas (1) to (4), Fourier transform is performed according to the following formula, and the amplitude of the nth-order component _An and phase _Pn are obtained.

Here, the amplitude A ₀ represents an error in the radius with respect to the perfect circle that is the reference line, the amplitude A ₁ represents the eccentricity from the perfect circle that is the reference line, the amplitude A ₂ represents the elliptical component, The amplitude A ₃ represents a triangular component, and the amplitude A ₄ represents a square component. P ₀ is not necessary.

When the analysis inner diameter shape parameters (A _n , P _n ) of these n-order components are subjected to inverse Fourier transform, and the amount of protrusion from the reference line L0 is expressed by a function T (θ) of the angle θ, equation (5) is obtained. become.

  Next, calculation is performed with k = 4 in equation (5). This is because the deformation of the bore 206 of the model block 204 can be substantially reproduced by performing the frequency analysis from the 0th order to the 4th order as described above.

Therefore, in equation (5), k = 4, and A ₁ × cos (θ + P ₁ ), A ₂ × cos (2θ + P ₂ ), A ₃ × cos (3θ + P ₃ ), A ₄ × cos (4θ + P ₄ ) When the waveforms of the four frequencies are plotted, FIG. 11 is obtained.

  Next, when the waveforms of these four frequencies are synthesized, the polarity is inverted to correct the shape, and plotted, the result is as shown in FIG.

In step S13, the higher-order computer 402 performs inverse Fourier transform on the analysis inner diameter shape parameters (A _n , P _n ).

  In step S <b> 14, the host computer 402 converts the inverse Fourier transformed data into a position in the Y direction of the machining tip 34 with respect to the rotation axis A of the turntable 302, and the rotation angle of the cylinder block 200 and the protrusion amount of the machining tip 34. A processing chip advance / retreat map representing the relationship between

  In step S15, the high-order computer 402 generates a detailed machining tip advance / retreat map for internal diameter processing by proportional interpolation processing based on the machining tip advance / retreat map, and stores the detailed machining chip advance / retreat map in the synchronous controller 66. To do. As shown in FIG. 13A, the detailed machining chip advance / retreat map has a trajectory S of the actual machining chip 34 having a spiral shape when the locus of the machining tip 34 of the machining chip advance / retreat map is R1A to R4A. The interval between the trajectories S is necessary because it is narrower than the interval between the trajectories R1A to R4A.

Specifically, for example, as shown in FIG. 13B, the position of a point S1 on the trajectory S located between the trajectories R1A and R2A adjacent to each other in the vertical direction is obtained. A straight line V passing through the point S1 is drawn, and intersections between the straight line V and the trajectories R1A and R2A are defined as points V1 and V2. Furthermore, the distance in the height direction between the point V1 and the point V2 is ΔZ, the distance in the horizontal direction between the point V1 and the point V2 is ΔR, the distance in the height direction from the point V2 to the point S1 is δz, and from the point V2 The position of the point S1 is obtained according to the following formula (6), where δr is the horizontal interval to the point S1.
ΔR: δr = ΔZ: δz (6)

  In step S <b> 16, the synchronization controller 66 moves the machining tip 34 in the Y direction relative to the rotation axis of the turntable 302 according to the stored machining tip advance / retreat map based on the rotation angle of the cylinder block 200 and the position of the machining tip 34 in the X direction. Find the position.

  In step S17, the inner diameter of the hole 202 of the cylinder block 200 is machined by the synchronous controller 66 in accordance with the position of the machining tip 34 in the Y direction.

  Step S18 determines whether machining has been completed for all cylinders. If this determination is YES, the process ends. If NO, the process returns to step S13.

  In the above control, steps S7 and S17 correspond to processing steps, and steps S4 and S11 correspond to measurement steps.

  In the inner diameter machining apparatus 10 of the present embodiment, the machining tip 34 is disposed between the piezo actuator 42 and the cylinder block 200, so that the piezo actuator 42 does not hit the inner diameter surface of the hole 202 of the cylinder block 200. This adjusts the position of the piezo actuator and the machining tip according to the hole depth of the cylinder block compared to the case where the piezo actuator is arranged in parallel with the machining tip so as to protrude to the cylinder block side from the machining tip. Therefore, the configuration of the inner diameter machining apparatus can be simplified. In addition, since the machining tip 34 advances and retreats due to the expansion and contraction of the plurality of piezoelectric elements, the responsiveness of the advancing and retreating operation of the machining tip is improved as compared with the case where the machining tip is advanced and retracted using a cam mechanism or the like. Therefore, it is possible to perform highly accurate inner diameter processing with a simple configuration.

  In the inner diameter machining apparatus 10 of the present embodiment, the position of the machining tip 34 in the Y direction is set with reference to the rotation axis A of the turntable 302, and therefore the machining tip 34 has a reference to the inner diameter surface of the hole 202 of the cylinder block 200. There is no need to set the advance / retreat amount. Therefore, the inner shape of the hole 202 of the cylinder block 200 is changed to that of the model block 204 even if the inner shape of the hole 202 of the cylinder block 200 is not made to be a highly accurate circular shape in the boring step that is a step before the inner diameter machining step. The inner diameter of the bore 206 can be machined. Therefore, an increase in the cycle time of the boring process can be suppressed.

  2. Description of the Related Art Generally, an apparatus that performs inner diameter processing while rotating a processing head (processing tip) in a state in which a cylinder block is fixed is known in the inner diameter processing of a cylinder block hole. When the piezo actuator used in the inner diameter device according to the present invention is used in such an apparatus, there is a possibility that the electric wire connected to the actuator main body is entangled when the machining head rotates. However, in the inner diameter machining apparatus of the present embodiment, the cylinder block is rotated with the machining head fixed, so that the electric wire does not get tangled.

  The present invention is not limited to the above-described embodiment, and can be implemented in various forms within the scope of the gist of the present invention.

  The inner diameter machining apparatus according to the present invention uses a piezoelectric element as means for advancing and retracting the machining chip in this embodiment, but a giant magnetostrictive material may be used instead of the piezoelectric element. In this case, it is only necessary to apply a magnetic field to the giant magnetostrictive material by supplying an electric current from the piezo driver to the giant magnetostrictive material via an electric wire, thereby expanding and contracting the giant magnetostrictive material. Thereby, there can exist the same effect as this embodiment using a piezoelectric element.

  In this embodiment, the machining tip is moved relative to the cylinder block by the moving mechanism. However, in the state where the apparatus main body is fixed without the moving mechanism, the rotational drive mechanism is moved to the depth of the hole of the cylinder block. The machining tip may be moved relative to the cylinder block by moving in the direction.

  The workpiece that can be machined by the bore machining apparatus according to the present invention is not limited to the cylinder block described above. For example, a bearing or the like can be used as the workpiece.

DESCRIPTION OF SYMBOLS 10 ... Inner diameter processing apparatus 12 ... Movement mechanism 16 ... Control part 30 ... Processing head 34 ... Processing chip 42 ... Piezo actuator 66 ... Synchronous controller 72 ... Piezo driver 200 ... Cylinder block 202 ... Hole 204 ... Model block 206 ... Bore 400 ... Inner surface Shape measuring instrument 402 ... host computer

Claims (6)

An inner diameter machining method of a workpiece for machining an inner diameter of a hole formed in the workpiece,
A cutting tool is disposed between the piezoelectric element or the giant magnetostrictive material and the workpiece,
While rotating the workpiece by the rotation means, while advancing and retracting the cutting tool in the radial direction of the hole in the piezoelectric element or the giant magnetostrictive material, by relatively moving in the depth direction of the hole, the A machining step for machining the inner diameter of the hole;
Measuring the inner diameter shape data of a workpiece model that has already been machined,
Perform frequency analysis based on the inner diameter shape data measured in the measuring step to reproduce the deformation of the work model,
A voltage applied to the piezoelectric element or a magnetic field applied to the giant magnetostrictive material is controlled by a control unit so that the cutting tool moves forward and backward based on the reproduced shape of the workpiece model . Inner diameter machining method. In the inside diameter processing method of the workpiece according to claim 1 ,
An internal diameter machining method for a workpiece, wherein the workpiece is a cylinder block. An inner diameter machining apparatus for a workpiece for machining an inner diameter of a hole formed in the workpiece,
A blade provided so as to be able to contact the inner diameter surface of the hole in a state in which the workpiece is rotated by a rotating means;
Moving means for moving the cutting tool relative to the workpiece in the depth direction of the hole;
A piezoelectric element or a giant magnetostrictive material that advances and retracts the blade in the radial direction of the hole;
Frequency analysis is performed based on the inner diameter shape data of the workpiece model that has already been machined to reproduce the deformation of the workpiece model, and the cutting tool is advanced and retracted based on the reproduced shape of the workpiece model. A control unit that controls an applied voltage or a magnetic field applied to the giant magnetostrictive material ,
An inner diameter machining apparatus for a workpiece, wherein the cutting tool is disposed between the piezoelectric element or the giant magnetostrictive material and the workpiece. In the inside diameter processing apparatus of the workpiece according to claim 3,
A holder for holding the blade,
A head portion provided with the holder;
An actuator having the piezoelectric element or the giant magnetostrictive material disposed in a chamber formed in the head portion and pressing the holder radially outward of the hole;
An urging member provided on the head portion and urging the holder toward the actuator;
The workpiece inner diameter processing apparatus, wherein the holder is formed with a through hole that communicates the chamber with the outside. In the inside diameter processing apparatus of the workpiece according to claim 4,
The actuator is formed with a curved surface in contact with the opening of the through hole in the holder. 6. The workpiece inner diameter machining apparatus according to claim 3 , wherein the workpiece is a cylinder block.

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