JP2015031537A - Measuring method and measuring apparatus for incomplete round bore shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method and a measuring apparatus for an incomplete round bore shape capable of high-accuracy measurement in a short cycle time at measurement and at low costs, using a cam mechanism.SOLUTION: A measuring method for an incomplete round bore shape comprises: a pretension step (step S111) for controlling the torque of a shaft motor 24 constant to apply pretension to a contact needle 14 through a cam 122; and a synchronization control rotation step (step S112) for rotating the cam 122 and a rotation drive mechanism 20 under synchronous control. The measuring method controls the torque of the shaft motor 24 constant with the contact needle 14 in contact with the irregularity on an inner peripheral surface of the incomplete round bore to displace the cam angle θ of the cam 122, and causes the contact needle 14 to make one rotation along the inner peripheral surface of the incomplete round bore to determine the displaced cam angle θ of the cam 122 by a second rotary encoder 241 and a first rotary encoder 252 to thereby measure the incomplete round bore shape.

Description

  The present invention relates to a non-circular bore shape measuring method and measuring apparatus. More specifically, the present invention relates to a non-circular bore shape measuring method and measuring apparatus using a cam mechanism that measures the shape of a hole formed in a workpiece having the same shape as a cross-sectional non-circular bore already formed.

Conventionally, in an automobile manufacturing process, a bore of a cylinder block of an engine is cut and then a cylinder head, a crankcase, and the like are assembled to the cylinder block.
Here, since the piston accommodated in the bore has a perfect circular cross section, the bore is cut so that the cross sectional shape of the bore is close to a perfect circle.

  However, even if the bore of the cylinder block is processed into a perfect circular cross section, the shape of the bore is deformed when a cylinder head, a crankcase, or the like is assembled. If the bore is deformed in this way, it becomes a factor that increases the sliding resistance between the bore and the piston when the engine is used, and the engine may not exhibit the desired performance.

Therefore, when machining the bore of the cylinder block, a dummy head imitating the cylinder head is attached and the bore is machined. When the bore machining is finished, the dummy head is removed.
However, there is a problem in that productivity is greatly reduced if a dummy head or the like is attached or removed each time the cylinder block is bored.

In order to solve this problem, the following methods have been proposed (see Patent Documents 1 and 2).
That is, first, the dummy head is mounted on the cylinder block, and the bore is machined into a perfect circular shape by a machine tool.

Next, the dummy head is removed from the cylinder block. Then, since the stress due to the assembly of the dummy head is eliminated, the bore shape is deformed to become a non-circular cross section. NC data is generated by measuring the overall shape of the bore having a non-circular cross section.
Specifically, the NC data is obtained by setting measurement points at predetermined intervals along the bore axis of the bore having a non-circular cross section when the dummy head is removed, and the bore at each measurement point. The cross-sectional shape is measured.

Thereafter, based on the generated NC data, a non-circular bore is formed by boring a non-processed cylinder block without mounting a dummy head.
In this way, even if the bore is processed without attaching the dummy head to the cylinder block, the bore becomes a perfect circle when the cylinder head is mounted.

JP 2007-313619 A International Publication No. 2009/125638

  In order to check whether the non-circular bore formed in the cylinder block is processed as designed, a non-contact dedicated sensor such as a laser sensor, eddy current sensor or air sizing sensor is used. The bore shape was measured.

However, the dedicated sensor is expensive, and in addition, there is a problem that the rotation time of the rotary part is restricted due to wear of the rotary part or wired communication, and the cycle time at the time of measurement is deteriorated.
In addition, when using an air sizing sensor that detects the back pressure by blowing air on the inner peripheral surface of the bore to the dedicated sensor, the air to be released diffuses in the case of a non-circular bore, There was a problem that the measurement accuracy deteriorated.

  The present invention is intended to solve the above-described problems, and an object thereof is to provide a non-circular bore shape measuring method and measuring apparatus that are inexpensive, have a short cycle time during measurement, and are capable of highly accurate measurement. It is in.

  (1) A non-circular bore shape measuring device (for example, a non-circular bore shape measuring device 1 described later) that measures a non-circular bore shape is a cam mechanism (for example, described later) that is inserted into the non-circular bore. Cam 122), a servo motor (for example, a shaft motor 24 described later) connected to the cam mechanism and rotating the cam mechanism, and a servo motor encoder (for example, described later) for detecting the rotation angle of the cam mechanism. The second rotary encoder 241) and a contact mechanism (for example, contact needle 14 described later) that can protrude and retract on the outer peripheral surface by rotating the cam mechanism, and a rotatable spindle mechanism (for example, rotation drive described later). A mechanism 20) and a spindle mechanism encoder (for example, a first rotary encoder 252 described later) for detecting the rotation angle of the spindle mechanism, and the torque of the servo motor A pre-tensioning step (for example, step S111 described later) for pre-tensioning the contact needle through the cam mechanism, and a synchronous control rotation step for rotating the cam mechanism and the spindle mechanism with synchronous control ( For example, step S112), which will be described later, includes a constant control of the torque of the servo motor in a state in which the contact needle is brought into contact with the unevenness of the inner peripheral surface of the non-circular bore by the pretensioning process, The servo angle of the cam mechanism and the encoder for the spindle mechanism are changed by displacing the cam angle of the cam mechanism and causing the contact needle to make one turn along the inner peripheral surface of the non-circular bore by the synchronous control rotation step. Is used to identify the displaced cam angle of the cam mechanism in one round of the non-circular bore and measure the non-circular bore shape. Method of measuring the non-circular bore shapes characterized by.

According to the invention of (1), the torque of the servo motor is controlled to be constant, a pre-tensioning step for pre-tensioning the contact needle via the cam mechanism, and a synchronous control rotation step for rotating the cam mechanism and the spindle mechanism by synchronous control. And measure the non-circular bore shape.
In the pretensioning process, the cam angle of the cam mechanism is displaced by constant control of the servomotor torque with the contact needle in contact with the irregularities on the inner peripheral surface of the non-circular bore, and the servomotor encoder and spindle The displaced cam angle of the cam mechanism is specified using a mechanism encoder. This specified cam angle corresponds to the inner diameter shape at a certain position on the circumference of the non-circular bore.
In the synchronous control rotation process, the servomotor torque controlled constant in the pretensioning process is maintained, and the contact needle is rotated once along the inner peripheral surface of the non-circular bore so that the servomotor encoder and spindle mechanism Using the encoder, the cam angle at each position on the circumference of the non-circular bore is specified. Thereby, the cam angle on the entire circumference of the non-circular bore is specified, and the inner diameter shape on the entire circumference of the non-circular bore is measured.
According to the above invention, since it has a simple configuration including the cam mechanism, the servo motor, the servo motor encoder, the spindle mechanism, and the spindle mechanism encoder, it can be manufactured at low cost. Further, the contact needle can be rotated without any rotation limitation by the spindle mechanism, and the cycle time at the time of measurement can be shortened. In addition, by controlling the torque of the servo motor at the time of contact with the contact needle to identify the cam angle displaced by the cam mechanism and measuring the inner diameter shape of the non-circular bore, high-precision measurement can be realized.

  (2) A state in which the cam angle of the cam mechanism is set to a predetermined angle (for example, a predetermined angle θo described later) by the pre-tensioning step and the contact needle is brought into contact with the irregularities on the inner peripheral surface of the non-circular bore. The cam angle of the cam mechanism is corrected in accordance with a reaction force (for example, an estimated reaction force Fe described later) output from the contact needle by constant control of the torque of the servo motor. The cam angle of the cam mechanism is displaced from the predetermined angle, and the contact needle is rotated once along the inner peripheral surface of the non-circular bore by the synchronous control rotation step, thereby The method for measuring a non-circular bore shape according to (1), wherein the displaced cam angle of the cam mechanism in one circumference of the non-circular bore is specified using the spindle mechanism encoder. .

  According to the invention of (2), by using the reaction force from the contact needle that is output to the torque of the servo motor, there is no need to provide extra parts to identify the displaced cam angle of the cam mechanism. Can be reduced. Thereby, since it is a simple structure, it can manufacture at low cost.

  (3) The cam angle of the cam mechanism is set to a predetermined angle (for example, a predetermined angle θo described later) by the pre-tensioning step, and the contact needle is brought into contact with the irregularities on the inner peripheral surface of the non-circular bore. By controlling the torque of the servo motor to a constant value, a mechanical mechanism resistance force (for example, a later-described mechanism) is applied from a load force (for example, a later-described load force Fl) based on the torque (for example, a later-described torque Tl) of the servo motor. When the reaction force from the contact needle (for example, estimated reaction force Fe described later) is calculated by subtracting the mechanism resistance force Fm), the cam angle of the cam mechanism is a predetermined angle from the calculated reaction force. After subtracting a constant force corresponding to the reaction force (for example, a constant force Fwo described later), a reaction force corresponding angle of the cam angle of the cam mechanism (for example, a reaction force corresponding angle θco described later) is calculated, Calculated reaction force The angle is added to the predetermined angle, and the cam angle of the cam mechanism is displaced according to a correction angle (for example, a correction angle θam described later) obtained by adding the reaction force corresponding angle to the predetermined angle. The cam mechanism in one round of the non-circular bore using the servo motor encoder and the spindle mechanism encoder by causing the contact needle to make one round along the inner circumferential surface of the non-circular bore (1) or (2), wherein the displaced cam angle is specified.

  According to the invention of (3), the reaction force from the contact needle can be calculated with high accuracy by subtracting the mechanical mechanism resistance from the torque of the servo motor. For this reason, the displaced cam angle of the cam mechanism to be corrected according to the reaction force can be specified with high accuracy, and high-accuracy measurement can be realized.

  (4) The spindle mechanism has a bore working tool (for example, a cutting tool 13 described later) that can project and retract on an outer peripheral surface by rotating the cam mechanism, and the servo mechanism is used to drive the cam mechanism ( For example, the cam 121) described later is rotated to change the protruding amount of the bore processing tool, and the non-circular bore is processed using the servo motor encoder and the spindle mechanism encoder. The method for measuring a non-circular bore shape according to any one of (1) to (3).

  According to the invention of (4), the spindle mechanism, the servo motor, the servo motor encoder, and the spindle mechanism encoder use the same parts for machining the non-circular bore and measuring the non-circular bore shape. Less. Thereby, since it is a simple structure, it can manufacture at low cost.

  (5) A cam mechanism (for example, a cam 122 described later) inserted into the non-circular bore, a servo motor (for example, a shaft motor 24 described later) connected to the cam mechanism and rotating the cam mechanism, An encoder for a servo motor (for example, a second rotary encoder 241 described later) that detects the rotation angle of the cam mechanism, and a contact needle (for example, a contact needle 14 described later) that can project and retract on the outer peripheral surface by rotating the cam mechanism. ) And a rotatable spindle mechanism (for example, a rotation driving mechanism 20 described later), a spindle mechanism encoder (for example, a first rotary encoder 252 described later) for detecting a rotation angle of the spindle mechanism, and the servo A constant torque of the motor is controlled, a pretension is applied to the contact needle through the cam mechanism, and the cam mechanism and the spindle mechanism are connected. The cam mechanism is displaced in a cam angle by constantly controlling the torque of the servo motor with the contact needle in contact with the irregularities on the inner peripheral surface of the non-circular bore. Displacement of the cam mechanism in one round of the non-circular bore using the servo motor encoder and the spindle mechanism encoder by causing the contact needle to make one round along the inner circumferential surface of the non-circular bore. A non-circular bore shape measuring device (for example, a non-circular bore shape) using a cam mechanism, characterized in that it has a measuring means (for example, step S11 described later) for measuring the non-circular bore shape. Non-round hole drilling device 1) described later.

  According to the invention of (5), the same actions and effects as the invention of (1) can be achieved.

  According to the present invention, it is possible to provide a non-circular bore shape measuring method and measuring apparatus that are inexpensive, have a short cycle time during measurement, and are capable of highly accurate measurement.

It is a schematic block diagram of the non-round hole drilling apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the protrusion amount of the cutting bit of the non-round hole drilling apparatus which concerns on the said embodiment. It is a figure which shows the relationship between the cam angle of the non-round hole drilling apparatus which concerns on the said embodiment, and the protrusion amount of a cutting tool. It is a schematic diagram which shows the protrusion amount of the contact needle of the non-round hole processing apparatus according to the embodiment. It is a figure which shows the relationship between the cam angle of the non-round hole processing apparatus which concerns on the said embodiment, and the protrusion amount of a contact needle. It is a block diagram which shows operation | movement of the synchronous controller at the time of the boring process of the non-round hole drilling apparatus which concerns on the said embodiment. It is a flowchart which shows the procedure which carries out the boring process of the bore | bore of a cylinder block using the non-round hole drilling apparatus which concerns on the said embodiment. It is sectional drawing which shows the cylinder block bored using the non-round hole drilling apparatus which concerns on the said embodiment. It is a figure for demonstrating the state which the cylinder block which concerns on the said embodiment deform | transformed. It is a block diagram which shows operation | movement of the synchronous controller at the time of the bore | bore shape measurement of the non-round hole drilling apparatus which concerns on the said embodiment. It is a figure which shows the torque which the cam of the contact needle of the non-round hole processing apparatus which concerns on the said embodiment receives. It is a flowchart which shows the procedure which measures the internal-diameter shape of the non-circular bore | bore of a cylinder block using the non-round hole processing apparatus which concerns on the said embodiment. It is a figure which shows the correction map which correct | amends the internal diameter shape of the non-circular bore of the cylinder block which concerns on the said embodiment. It is a schematic diagram which shows the internal diameter shape of the bore measured at the measurement point of the cylinder block which concerns on the said embodiment. It is sectional drawing which shows the internal diameter shape of the bore measured at one measuring point of the cylinder block which concerns on the said embodiment. It is the figure which represented the internal diameter shape of the bore measured at one measuring point of the cylinder block which concerns on the said embodiment by making a rotating shaft into a horizontal axis. It is the figure which compared the contact needle measuring method which concerns on the said embodiment, and the conventional measuring method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a non-round hole processing apparatus 1 as a non-round bore shape measuring apparatus according to an embodiment of the present invention.
The non-round hole drilling apparatus 1 inserts a machining head 10 into a bore of a cylinder block of an automobile engine as a workpiece, for example, and performs boring. Then, the machining head 10 is inserted into a non-circular bore formed by boring, and the inner diameter shape of the bore is measured.
The non-round hole processing apparatus 1 includes a rotation drive mechanism (spindle mechanism) 20 that rotates the machining head 10 and that can rotate itself, an advance / retreat mechanism 30 that moves the rotation drive mechanism 20 back and forth, and a control that controls these mechanisms. The apparatus 40 and the high-order computer 52 which analyzes the measurement result which measured the internal diameter shape of the bore | bore of a workpiece | work are provided.
The host computer 52 is connected to a CAE system 54 that performs workpiece simulation analysis and a CAD system 53 that performs workpiece design.

The rotational drive mechanism 20 includes a cylindrical arbor 21, a shaft 22 housed in the arbor 21, an arbor motor 23 that rotationally drives the arbor 21, a shaft motor (servo motor) 24 that rotationally drives the shaft 22, And a housing 25 that houses the arbor motor 23.
Here, the rotation axis of the arbor 21 and the rotation axis of the shaft 22 are coaxial.

  In addition to the arbor motor 23, the housing 25 includes a bearing 251 that rotatably holds the arbor 21, a first rotary encoder (spindle mechanism encoder) 252 that detects a rotation speed and a rotation angle of the arbor 21, and an advance / retreat mechanism 30. And a nut portion 253 to be screwed together.

  The shaft motor 24 is provided with a second rotary encoder (servo motor encoder) 241 that detects the rotation speed and rotation angle (cam angle) of the shaft 22.

The advance / retreat mechanism 30 is a feed screw mechanism, and includes a shaft portion 31 in which a screw is engraved, an advance / retreat motor 32 that rotationally drives the shaft portion 31, and a third rotary that detects the rotation speed and rotation angle of the shaft portion 31. And an encoder 33. The shaft portion 31 is screwed into the nut portion 253 of the housing 25.
According to this advance / retreat mechanism 30, the shaft portion 31 rotates by driving the advance / retreat motor 32, and the rotation drive mechanism 20 can be advanced / retracted.

  The machining head 10 is capable of projecting and retracting on the outer peripheral surface of the arbor 11, a cylindrical arbor 11 that is integrally connected to the arbor 21, a shaft 12 that is housed inside the arbor 11 and is integrally connected to the shaft 22, and the like. The cutting tool 13 is provided, and the contact needle 14 is provided on the outer peripheral surface of the arbor 11 so as to be able to project and retract on the distal end side of the shaft 22 with respect to the cutting tool 13.

A through-hole 111 extending in a direction intersecting the rotation axis of the arbor 11 is formed on the distal end side of the arbor 11.
The cutting tool 13 has a rod shape, is inserted into the through hole 111, and is biased toward the shaft 12 by a biasing means (not shown).

As shown in FIG. 2, the shaft 12 is provided with a cam 121 that presses the cutting tool 13 in a protruding direction.
The cam 121 has a perfect circle shape, for example. The shaft 12 is inserted in a position shifted from the center of the true circular cam 121. Thereby, the distance from the rotation center of the shaft 12 to the peripheral edge of the cam 121 changes continuously.
The shape of the cam 121 is not limited to a perfect circle, but a perfect circle is preferable in order to reduce costs.

  The base edge of the cutting tool 13 abuts on the periphery of the cam 121. Therefore, by changing the angle of the shaft 12 with respect to the arbor 11, the portion of the peripheral edge of the cam 121 that contacts the cutting bit 13 changes, and the amount of protrusion of the cutting bit 13 from the outer peripheral surface of the arbor 11 changes.

FIG. 2A is a schematic diagram illustrating a state where the protruding amount of the cam 121 is t1. FIG. 2B is a schematic diagram showing a state where the protruding amount of the cutting tool 13 is zero.
In FIG. 2, a straight line from the rotation center of the cam 121 to the farthest part of the peripheral edge of the cam 121 from the shaft 12 is defined as a reference line Q <b> 1 of the cam 121, and a straight line passing through the central axis of the cutting bit 13 is The reference line is K1. The angle formed between the reference line Q1 of the cam 121 and the reference line K1 of the cutting bit 13 is defined as a cam angle.

In a state where the protruding amount of the cutting tool 13 is t1, the cam angle is α1. Let α1 be the initial angle. On the other hand, the cam angle is (α1 + β1) when the protruding amount of the cutting bit 13 is zero.
When the radius of the cam 121 is Cr1 and the offset dimension from the center of the cam 121 to the center of rotation is Co1, the maximum dimension L11 and the minimum dimension L12 from the rotation center of the cam 121 to the base edge of the cutting bit 13 are as follows: It is represented by formulas (1) and (2).

L11 = Co1 × cos (α1) + Cr1 Formula (1)
L12 = Co1 × cos (α1 + β1) + Cr1 (2)

  From the above, the stroke of the cam angle is β1 (swing angle), the stroke of the protruding amount of the cutting tool 13 is t1, and the following equation (3) is established.

t1 = L11−L12 = Co1 × {cos (α1) −cos (α1 + β1)}
... Formula (3)

Based on this equation (3), the relationship between the cam angle and the cutting tool protrusion amount is shown in FIG.
As shown by the solid line in FIG. 3, the protruding amount of the cutting tool 13 changes nonlinearly, that is, in an arc shape with respect to the change of the cam angle. On the other hand, as shown by a broken line in FIG. 3, with an ideal cam, the protruding amount of the cutting bit changes linearly. Therefore, as compared with the case where the protruding amount of the cutting bit is changed linearly, the error of the protruding amount of the cutting bit 13 is near the middle between the cam angle α1 (initial angle) and the cam angle (α1 + β1). Become the largest.

Therefore, when it is desired to project the cutting tool 13 by Δt1, the cam angle (α1 + Δβ1) corresponding to the projecting amount (Δt1) is used as the cam angle command value. Thereby, the protrusion amount can be easily changed to a linear shape (linear).
Specifically, for example, a projection amount cam angle correspondence table 90 (see FIG. 1) in which the projection amount (Δt1) and the cam angle command value (α1 + Δβ1) are associated with each other is generated, and the main controller 41 is preliminarily generated. The command value (α1 + Δβ1) can be called by the synchronous controller 42 described later. The protrusion amount cam angle correspondence table 90 may be stored in the synchronization controller 42 itself, or may be output from the host computer 52 to the synchronization controller 42.

A through hole 112 extending in a direction intersecting the rotation axis of the arbor 11 is formed at a more distal end side of the through hole 111 of the arbor 11 with different positions in the circumferential direction on the through hole 111 and the arbor 21.
The contact needle 14 protrudes in the outer diameter direction by contacting the outer periphery of the cam 122. The contact needle 14 includes a tip 141, an advance / retreat rod 142, a support rod 143, and a retract spring 144.
The tip 141 is made of metal, has a sharp point in the outer diameter direction of the arbor 11, has a spherical portion at the tip, and comes into contact with the inner peripheral surface of the bore by protruding from the state inserted in the through hole 112.
The advance / retreat rod 142 has a rod shape and is inserted into the inner diameter side of the through-hole 112 continuously to the tip 141.
The support rod 143 extends in the axial direction of the arbor 11 inside the arbor 11, one end is fixed to the tip 141, the other end is connected to one end of the retract spring 144, and has a fulcrum at a substantially central portion.
The retract spring 144 is a spring that repels elastically and urges the other end of the support rod 143 from the inner diameter side to the outer diameter direction. Thus, in a standby state where the tip 141 is not pressed in the outer diameter direction of the arbor 11 by the advance / retreat rod 142, the retract spring 144 presses the other end of the support rod 143 in the outer diameter direction, and the action of the support rod 143 is supported by the fulcrum. The tip 141 is fixed to one end of the support rod 143, and the tip 141 is retracted toward the shaft 12.

As shown in FIG. 4, the shaft 12 is provided with a cam 122 that presses the contact needle 14 in a protruding direction.
The cam 122 has, for example, a perfect circle shape. The shaft 12 is inserted at a position shifted from the center of the true circular cam 122. Thereby, the distance from the rotation center of the shaft 12 to the peripheral edge of the cam 121 changes continuously.
In addition, the cam 122 is fixed to the shaft 12 at a position different from the fixing position of the cam 121 of the cutting tool 13, and the eccentric positions of the cam 121 and the cam 122 are different from each other.
The shape of the cam 122 is not limited to a perfect circle, but a perfect circle is preferable in order to reduce costs.

  The proximal end edge on the inner diameter side of the advance / retreat rod 142 of the contact needle 14 abuts on the peripheral edge of the cam 122. Therefore, by changing the angle of the shaft 12 with respect to the arbor 11, the portion of the peripheral edge of the cam 122 that contacts the advance / retreat rod 142 changes, and the amount of protrusion of the tip 141 of the contact needle 14 from the outer peripheral surface of the arbor 11 changes. To do.

FIG. 4A is a schematic diagram showing a state where the protruding amount of the cam 122 is t2. FIG. 4B is a schematic diagram showing a state where the protruding amount of the contact needle 14 is zero.
In FIG. 4, a straight line from the rotation center of the cam 122 to the farthest part of the peripheral edge of the cam 122 from the shaft 12 is defined as a reference line Q <b> 2 of the cam 122, and a straight line passing through the central axis of the contact needle 14 is The reference line K2. The angle formed between the reference line Q2 of the cam 122 and the reference line K2 of the contact needle 14 is defined as a cam angle.

In a state where the protruding amount of the contact needle 14 is t2, the cam angle is α2. Let α2 be the initial angle. On the other hand, when the protruding amount of the contact needle 14 is zero, the cam angle is (α2 + β2).
When the radius of the cam 122 is Cr2 and the offset dimension from the center of the cam 122 to the rotation center is Co2, the maximum dimension L21 and the minimum dimension L22 from the rotation center of the cam 122 to the base end edge of the advancing / retreating rod of the contact needle 14 are Are represented by the following formulas (4) and (5).

L21 = Co2 × cos (α2) + Cr2 Formula (4)
L22 = Co2 × cos (α2 + β2) + Cr2 (5)

  From the above, the stroke of the cam angle is β2 (swing angle), the stroke of the protruding amount of the contact needle 14 is t2, and the following equation (6) is established.

t2 = L21−L22 = Co2 × {cos (α2) −cos (α2 + β2)}
... Formula (6)

Based on this equation (6), the relationship between the cam angle and the contact needle protrusion amount is shown in FIG.
As shown by the solid line in FIG. 5, the protrusion amount of the contact needle 14 changes nonlinearly, that is, in an arc shape with respect to the change of the cam angle. On the other hand, as shown by a broken line in FIG. 5, with an ideal cam, the protruding amount of the contact needle changes linearly. Therefore, as compared with the case where the protruding amount of the contact needle is changed linearly, the error of the protruding amount of the contact needle 14 is near the middle between the cam angle α2 (initial angle) and the cam angle (α2 + β2). Become the largest.

Therefore, when the contact needle 14 is protruded by Δt2, the cam angle (α2 + Δβ2) corresponding to the protrusion amount (Δt2) is used as the cam angle command value. Thereby, the protrusion amount can be easily changed to a linear shape (linear).
Specifically, for example, a projection amount cam angle correspondence table 90 (see FIG. 1) in which the projection amount (Δt2) and the cam angle command value (α2 + Δβ2) are associated with each other is generated, and the main controller 41 is preliminarily generated. The command value (α2 + Δβ2) can be called by the main control device 41 described later.

First, the case where the machining head 10 is inserted into the bore of the workpiece and boring is performed will be described.
Returning to FIG. 1, the control device 40 advances or retards the phase of the rotation angle of the shaft 22 with respect to the phase of the rotation angle of the arbor 21 while rotating the arbor 21 and the shaft 22 synchronously. Thereby, the protrusion amount of the cutting bit 13 from the outer peripheral surface of the arbor 11 of the cutting bit 13 can be adjusted.
The control device 40 includes a main control device 41, a synchronization controller 42, a first servo amplifier 43, a second servo amplifier 44, and a third servo amplifier 45.

  The main control device 41 drives the arbor motor 23 and the advance / retreat motor 32 via the first servo amplifier 43 and the third servo amplifier 45 according to the output from the host computer 52, and the cutting speed of the cutting bit 13 with respect to the workpiece and on the axis line Control the position of the. That is, the main control device 41 is a device that operates in the same manner as a so-called NC (numerical value) control device. The main control device 41 includes a memory 91 that stores a protrusion amount cam angle correspondence table 90.

  The synchronous controller 42 is configured such that the direction of the cutting bit 13 with respect to the workpiece bore (that is, the rotation angle of the arbor 21) and the position on the axis line of the cutting bit 13 with respect to the bore of the workpiece (that is, the rotation angle of the shaft portion 31 of the advance / retreat mechanism 30). In response to the command signal is output. As a result, the shaft motor 24 is driven via the second servo amplifier 44 to adjust the protruding dimension of the cutting bit 13 (that is, the protruding amount of the cutting bit 13 from the outer peripheral surface of the arbor 11).

Specifically, a map showing the relationship between the rotation angle of the arbor 21 and the position of the machining head 10 in the forward / backward direction (that is, the position on the axis of the cutting bit 13 with respect to the bore of the workpiece) and the protruding amount of the cutting bit 13 The map is generated based on the output from the host computer 52, and this map is stored in the memory in the synchronization controller 42 by the synchronization controller 42.
A map is an array of parameters. That is, the above-described map shows the relationship between the rotation angle of the arbor 21 and the protruding amount of the cutting bit 13 for each position in the advancing / retreating direction of the machining head 10 (that is, the position on the axis of the cutting bit 13 with respect to the bore of the workpiece). The bore cross-sectional two-dimensional data is obtained and arranged in the axial direction.

The synchronous controller 42 then rotates the rotation speed and rotation angle of the arbor 21 detected by the first rotary encoder 252 (specifically, the number of pulses generated by the rotary encoder per unit time, that is, the number of pulses of the sampling time), In addition, based on the rotation angle of the shaft portion 31 detected by the third rotary encoder (specifically, the number of pulses generated by the rotary encoder per unit time, that is, the number of pulses of the sampling time), The shaft motor 24 is driven via the second servo amplifier 44 with reference to the map showing the relationship of the protruding amount of the cutting tool 13 stored in the memory.
At this time, the rotation speed and rotation angle of the shaft 22 detected by the second rotary encoder 241 by the second servo amplifier 44 (specifically, the number of pulses generated by the rotary encoder per unit time, that is, the pulse of the sampling time) The shaft motor 24 is feedback-controlled according to the number.

The control of the shaft 22 by the synchronous controller 42 will be described with reference to FIG.
FIG. 6 is a block diagram showing the operation of the synchronization controller 42.
When the arbor 21 and the shaft 22 are completely synchronized, first, the rotational speed of the arbor 21 is multiplied by the resolution (PG2) of the second rotary encoder 241 that detects the rotational speed of the shaft 22, and the rotational speed of the shaft 22 is also multiplied. Is multiplied by the resolution (PG1) of the first rotary encoder 252 that detects the rotation speed of the arbor 21, and the difference between the two is calculated.
The reason for performing such multiplication is that the resolution (PG1) of the first rotary encoder 252 and the resolution (PG2) of the second rotary encoder 241 are different, so that the resolution is adjusted in consideration of these resolution ratios. is there.

Next, the calculated difference is calculated as a speed error, and the speed error is integrated to obtain a position error.
Next, the feed forward amount is obtained from the rotation speed of the arbor 21 and the speed error and the position error are added to obtain a speed command to the shaft motor 24.
Then, the phase difference between the arbor and the cam is maintained, and the protruding amount of the cutting bit 13 becomes constant.

On the other hand, when the phases of the arbor 21 and the shaft 22 are shifted, first, when the rotation angle of the shaft portion 31 for moving the machining head 10 back and forth is acquired, the position of the machining head 10 in the forward / backward direction (that is, the cutting bit 13 is obtained). The position of the arbor 21 and the amount of protrusion of the cutting tool 13 are calculated according to the calculated position of the machining head 10 in the advancing / retreating direction by the map changer. The map (two-dimensional cross-section data of the bore) is switched.
Further, when the map address converter acquires the rotation speed and rotation angle of the arbor 21, the map address converter obtains the rotation position of the arbor 21.
Next, the map address converter refers to the above-mentioned map, calls the protrusion amount data of the cutting bit 13 corresponding to the rotation angle of the arbor 21, extracts the difference from the previous data, and changes this difference. The amount (that is, speed) is added to the rotational speed command of the shaft motor 24.

  Next, a procedure for boring a bore of a cylinder block of an automobile engine using the non-round hole drilling apparatus 1 configured as described above will be described with reference to a flowchart of FIG.

  First, in step S1, as shown in FIG. 8A, the dummy head 70 is attached to the cylinder block 60, which is a cylinder block material, with bolts 71. The dummy head 70 is made of a shape and material simulating a product cylinder head, and a hole into which the machining head 10 of the non-round hole machining apparatus 1 can be inserted is formed at the center.

  Next, in step S2, the cylinder block 60 is disposed at a predetermined position, and the bore 61 is machined to a desired roundness by the non-round hole drilling apparatus 1.

  Next, in step S <b> 3, the bolt 71 is released from the cylinder block 60 and the dummy head 70 is removed. Then, as shown in FIG. 8B, the inner diameter of the bore 61 of the cylinder block 60 is slightly deformed from the state of FIG. This is because the stress due to the assembly of the dummy head 70 is released.

Specifically, as shown in FIG. 9A, the cylinder block 60 is formed with four bores 61 arranged in a straight line. A bolt hole 72 into which the bolt 71 is screwed is formed around each bore 61.
When the dummy head 70 is removed from the cylinder block 60, the pressing force by the dummy head 70 is removed, so that the inner diameter shape of the bore 61 on the dummy head side is deformed into an ellipse as shown in FIG. 9B. Further, since the stress acting between the screw thread of the bolt hole 72 and the screw thread of the bolt 71 is removed, the inner diameter shape of the bore 61 on the crankshaft side is rectangular as shown in FIG. Deform.

Here, when frequency analysis is performed on the inner diameter shape of the bore, frequency analysis up to the fourth order is performed. This is because the deformation of the bore of the cylinder block 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 cylinder block bore 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 the data in the data format, the amount of data can be considerably reduced and the data processing can be accelerated.
In other words, in order to form a hole with a non-circular cross section so as to eliminate the deformation of the bore of the cylinder block when the cylinder head is assembled to the cylinder block, frequency analysis from the 0th order to the 4th order may be performed. The amount of data is small.

  In addition, it is not limited to the fourth-order frequency analysis, and 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, 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 on the axis of the bore 61 of the cylinder block 60 after the dummy head 70 is removed, and stored in the host computer 52 as inner diameter shape data. The measurement of the inner diameter shape of the bore 61 uses the method described later.

  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 S6, the calculated analysis inner diameter shape parameter is input to the synchronous controller 42 of the non-round hole drilling apparatus 1 to generate a combined inner diameter shape map.

  In step S7, first, a cylinder block 60A which is a new cylinder block material different from the cylinder block 60 which has already been subjected to boring is arranged at a predetermined position. Next, under the control of the synchronous controller 42, the cylinder block 60A is subjected to boring processing based on the generated composite inner diameter shape map.

  In step S8, unlike the dummy head 70, a product cylinder head 80 to be used as an actual product is prepared. As shown in FIG. 8C, a new cylinder block 60A subjected to boring processing is provided on the product cylinder head 60A. 80 is attached with a bolt 81. Then, the bore 61A of the cylinder block 60A has the same roundness as the bore 61 of the cylinder block 60.

Second, the case where the machining head 10 is inserted into the bore 61A formed in the cylinder block 60A by performing boring and the inner diameter shape of the non-circular bore is measured will be described. This measurement is also performed in step S4 when performing the boring process.
Returning to FIG. 1, the control device 40 advances or retards the phase of the rotation angle of the shaft 22 with respect to the phase of the rotation angle of the arbor 21 while rotating the arbor 21 and the shaft 22 synchronously. Thereby, the protrusion amount of the contact needle 14 from the outer peripheral surface of the arbor 11 of the contact needle 14 can be adjusted.

  The synchronous controller 42 drives the arbor motor 23 and the advance / retreat motor 32 via the first servo amplifier 43 and the third servo amplifier 45 in accordance with the output from the host computer 52, such as a cylinder block 60A in which the bore 61A is formed. The probe needle speed with respect to the workpiece and the position on the axis are controlled.

  First, as a pretensioning process, the synchronous controller 42 controls the torque of the shaft motor 24 to be constant and applies pretension to the bore from the contact needle 14 via the cam 122. That is, in the pretensioning step, the outer periphery of the cam 122 and the proximal end of the advance / retreat rod 142 of the contact needle 14 are brought into contact with each other so that the contact needle 14 is brought into contact with the irregularities on the inner peripheral surface of the non-circular bore. By outputting a constant torque to 24, the cam angle of the cam 122 is controlled to be displaced.

  Then, as a synchronous control rotation process, the synchronization controller 42 refers to a predetermined map and refers to the direction of the contact needle 14 with respect to the non-circular bore of the work (that is, the rotation angle of the arbor 21) and the non-circular bore of the work. The position on the axis of the contact needle 14 (that is, the rotation angle of the shaft portion 31 of the advance / retreat mechanism 30) is controlled. At this time, similarly to the pretensioning process, the synchronous controller 42 controls to output a constant torque to the shaft motor 24 in a state where the contact needle 14 is in contact with the unevenness of the inner peripheral surface of the non-circular bore. . As a result, the shaft motor 24 is driven via the second servo amplifier 44, and the protruding dimension of the contact needle 14 (ie, the protruding amount of the contact needle 14 from the outer peripheral surface of the arbor 11) when a constant value of torque is output. The inner diameter shape of the non-circular bore is measured from the cam angle of the cam 122 that changes accordingly.

Specifically, the synchronization controller 42 refers to a predetermined map, and the rotation speed and rotation angle of the arbor 21 detected by the first rotary encoder 252 (specifically, pulses generated by the rotary encoder per unit time). And the rotation angle of the shaft portion 31 detected by the third rotary encoder (specifically, the number of pulses generated by the rotary encoder per unit time, that is, the pulse of the sampling time) Number).
At this time, the synchronous controller 42 simultaneously brings the outer periphery of the cam 122 into contact with the proximal end of the advancing / retreating rod 142 of the contact needle 14 so that the shaft motor 24 outputs a constant value torque stored in the memory. The rotation speed and rotation angle of the shaft 22 detected by the second rotary encoder 241 by the second servo amplifier 44 in a state where the contact needle 14 is in contact with the irregularities on the inner peripheral surface of the perfect circular bore (specifically, the unit The shaft motor 24 is feedback-controlled according to the number of pulses generated by the rotary encoder per time, that is, the number of pulses of the sampling time.

The control of the shaft 22 by the synchronous controller 42 will be described with reference to FIG.
FIG. 10 is a block diagram showing the operation of the synchronization controller 42. FIG. 11 is a diagram illustrating torque generated at the cam angle θ.
First, the synchronous controller 42 transmits an angle command of a predetermined angle θo to the shaft motor 24. Thus, the contact needle 14 is brought into contact with the irregularities on the inner peripheral surface of the non-circular bore in a state where the cam angle of the cam 122 is the angle θ.
At this time, as shown in FIG. 11, the workpiece reaction force Fw caused by bringing the contact needle 14 into contact with the inner peripheral surface of the bore with the cam angle of the cam 122 being the angle θ, and the arbor 11 and the advance / retreat rod 142 And a mechanical mechanism resistance force Fm caused by a friction force between them and a resistance force by the retract spring 144 are generated.
For this reason, the torque Tl applied to the shaft motor 24 is expressed by the following equation (7) as a moment by the cam 122.

  Tl = (Fm + Fw) × Co2 × sin (θ) (7)

  Next, the load force Fl is calculated from the angle θ and the torque Tl of the shaft motor 24, and the mechanical mechanism resistance force Fm calculated by the no-load force calculation at the time of no load is calculated from the angle command of the predetermined angle θo. The estimated reaction force Fe from the contact needle 14 is calculated by subtracting the mechanical mechanism resistance force (no load force) Fm from the load force Fl. Specifically, the load force Fl = Fm + Fw = Tl / {Co2 × sin (θ)} is calculated by modifying the equation (7), and the mechanical mechanism resistance force Fm = no-load torque To / {Co2 × sin ( θo)} is calculated, and the estimated reaction force Fe≈Fw = load force Fl−mechanical mechanism resistance force Fm is calculated.

  Next, an impedance controller that subtracts a constant force Fwo corresponding to the reaction force when the cam angle of the cam 122 is the predetermined angle θo from the calculated estimated reaction force Fe, and converts the differential reaction force into a corresponding cam angle. , The reaction force corresponding angle θco of the cam angle of the cam 122 is calculated, and an angle command obtained by adding the calculated reaction force corresponding angle θco to the predetermined angle θo of the angle command is transmitted. As a result, the cam angle of the cam 122 is displaced using the PID controller based on the angle command which is the correction angle θam (= θo + θco) obtained by adding the reaction force corresponding angle θco to the predetermined angle θo, and the second encoder and the first encoder Is used to identify the displaced cam angle θ of the cam 122.

As described above, the cam angle θ at a certain position on the circumference of the non-circular bore can be specified. And while performing such control, the contact needle 14 is rotated once along the inner peripheral surface of the bore without changing the position on the axis of the bore by the synchronous control rotation process, so that the entire circumference of the non-circular bore is obtained. The upper cam angle θ is specified, and the inner diameter shape on the entire circumference of the non-circular bore is measured by calculating from the cam angle θ by the inner diameter dimension Lre.
The inner diameter dimension Lre is expressed by the following equation (8) shown in FIG. 11 when the offset dimension from the center of the cam 122 to the center of rotation is Co2, the radius of the cam 122 is Cr2, and the length of the contact needle 14 is Ls. expressed.

  Lre = Co2 × cos (θ) + Cr2 + Ls (8)

  This measurement is made at predetermined intervals on the axis of the non-circular bore.

  The procedure for measuring the non-round bore shape formed in the cylinder block of the automobile engine using the non-round hole processing apparatus 1 configured as described above will be described with reference to the flowchart of FIG.

In step S11, after inserting the machining head 10 of the non-round hole machining apparatus 1 into the non-round bore of the workpiece, the tip 141 of the contact needle 14 is aligned with the measurement point set at a predetermined position on the bore axis, The bore size Lre of the bore at the measurement point is measured.
Specifically, as S111, a pre-tensioning process is executed in which the torque of the shaft motor 24 is controlled to be constant and pre-tensioning is applied from the tip 141 of the contact needle 14 to the inner peripheral surface of the bore via the cam 122. Next, as S112, referring to a predetermined map, the direction of the contact needle 14 with respect to the non-circular bore of the work (that is, the rotation angle of the arbor 21) and the axis of the contact needle 14 with respect to the non-circular bore of the work The synchronous control rotation process which controls a position (namely, rotation angle of the axial part 31 of the advance / retreat mechanism 30) is performed. During the execution of S112, S111 is also executed at the same time. Then, in S113, the cam angle θ on the entire circumference of the non-circular bore on the predetermined axis is specified, and the inner diameter dimension Lre (= offset dimension Co2 × cos (θ) is calculated from the cam angle θ by the equation (8). (+ Radius Cr of cam 122 + contact needle length Ls) is calculated and the measurement process is executed.

In step S12, a tip wear correction term (Lam) is calculated.
FIG. 13 is a diagram showing a calculation map of the tip wear correction term (Lam) according to the present embodiment. The horizontal axis of FIG. 13 represents the number N of times of chip use. The vertical axis in FIG. 13 represents the tip wear correction term (Lam). The relationship between the chip use frequency N and the chip wear correction term (Lam) shown in FIG. 16 is defined as Lam = 1 at the beginning of a new chip, and the chip wear correction term increases as the chip use frequency N increases and the chip wear progresses. Is larger than 0 and lower than 1. When the tip wear increases, the cam angle θ of the cam 122 needs to be made smaller in order to cause the contact needle 14 to protrude to a constant protrusion amount. This calculation map is obtained in advance by experiments or the like and stored in the control device 40.
The chip wear correction term (Lam) is calculated by searching the calculation map of the chip wear correction term (Lam) in FIG. 13 using the chip usage count N stored in the memory 91 of the control device 40.

In step S13, the bore internal diameter Lre measured in step S11 is multiplied by the tip wear correction term (Lam) calculated in step S12 to calculate the bore internal diameter Lpr.
The inner diameter Lpr is expressed by the following formula (9).

  Lpr = Lre × Lam (9)

  From the above, the actual inner diameter dimension Lpr of the bore is calculated.

In step S14, it is determined whether or not the measurement at each measurement point set at a predetermined position on the bore axis has been completed.
Specifically, each measurement point Mn (n = 1, 2, 3, 4) is set, and it is determined whether or not the measurement is completed until n becomes 1 to 4.
If an affirmative determination is made in step S14, this routine ends. On the other hand, if a negative determination is made, the process returns to step S11.

FIG. 14 is a schematic diagram showing bore inner diameter shapes R1 to R4 measured at each measurement point M1 to M4.
As shown in FIG. 14, the bore inner diameter shapes R1 to R4 at the respective measurement points M1 to M4 are different from each other, and are non-circular shapes such as an ellipse, a triangle, a quadrangular shape, and an eccentric perfect circle. .

FIG. 15 is a cross-sectional view showing an inner diameter shape R2 of the bore measured at one of the measurement points M1 to M4, here, the measurement point M2. FIG. 16 is a view showing the bore shape R2 of the bore of FIG. 15 with the rotation angle as the horizontal axis.
In FIGS. 15 and 16, the position of the inner peripheral surface of the bore when the deformation amount of the bore is zero is set as a reference line Lo, the inner side is ΔL from the reference line Lo, and the inner side is LA by ΔL from the reference line Lo. The outside is LB.

  According to this embodiment, there are the following effects.

(1) A constant tension control for controlling the torque of the shaft motor 24 and pretensioning the contact needle 14 via the cam 122 (step S111), and synchronization for rotating the cam 122 and the rotary drive mechanism 20 by synchronous control. The control rotation step (step S112) is performed to measure the non-true circular bore shape.
In the pretensioning step (step S111), the torque of the shaft motor 24 is controlled to be constant with the contact needle 14 being in contact with the irregularities on the inner peripheral surface of the non-circular bore so that the torque of the shaft motor 24 is controlled to be constant. Thus, the cam angle of the cam 122 is displaced, and the displaced cam angle θ of the cam 122 is specified using the second rotary encoder 241 and the first rotary encoder 252. The specified cam angle θ corresponds to the inner diameter shape at a certain position on the circumference of the non-circular bore.
In the synchronous control rotation process (step S112), the torque of the shaft motor 24 controlled in the pretension process (step S111) is maintained, and the contact needle 14 is rotated once along the inner peripheral surface of the non-circular bore. Thus, the cam angle θ at each position on the circumference of the non-circular bore is specified using the second rotary encoder 241 and the first rotary encoder 252. Thus, the cam angle θ on the entire circumference of the non-circular bore is specified, and the inner diameter shape on the entire circumference of the non-circular bore is measured.
According to the present embodiment, the cam 122, the shaft motor 24, the second rotary encoder 241, the rotary drive mechanism 20, and the first rotary encoder 252 have a simple configuration, and therefore can be manufactured at low cost. Further, the contact needle 14 can be rotated by the rotation drive mechanism 20 without rotation limitation, and the cycle time at the time of measurement can be shortened. Furthermore, by controlling the torque of the shaft motor 24 at the time of contact with the contact needle 14 to identify the cam angle θ displaced by the cam 122 and measuring the inner diameter shape of the non-circular bore, highly accurate measurement is realized. it can.

  FIG. 17 is a diagram comparing the measurement method according to the present embodiment and the measurement method of the prior art. In FIG. 17, the conventional air sizing measurement method, laser measurement method, and eddy current measurement method are compared with the contact needle measurement method according to this embodiment. In FIG. 17, “Good” indicates that each factor is good, “Δ” indicates a slight adverse effect, and “X” indicates an adverse effect.

The conventional air sizing measurement method, laser measurement method, and eddy current measurement method are all methods using a non-contact sensor. In the air sizing measurement method, air is blown onto the inner peripheral surface of the bore to detect the back pressure. In the laser measurement method, the emitted laser is reflected on the inner peripheral surface of the bore and measured by the time difference between transmission and reception of the laser. In the eddy current measurement method, an eddy current is generated on the inner peripheral surface of the bore by the high-frequency magnetic flux generated from the sensor coil, and the impedance of the sensor coil changed at that time is measured.
Although the measurement accuracy is high according to the air sizing measurement method, when measuring the non-circular bore shape which is the object in the present embodiment, the released air diffuses and the measurement accuracy deteriorates. The material effect is adversely affected by the eddy current measurement method in which current is applied. In the temperature effect, the air sizing measurement method is adversely affected by changes in air flow. As for the influence of chips, according to the laser measuring method and the eddy current measuring method, adverse effects are exerted due to changes in the relative distance and the amount of energization due to the adhesion of the chips. With respect to the surface roughness effect, the laser measurement method has an adverse effect because the accuracy of laser reflection decreases. In the measurement speed, according to the air sizing measurement method, the measurement speed deteriorates because it takes time until the back pressure of the air is stabilized. The signal path is a wired path according to the laser measurement method and the eddy current measurement method, which restricts the rotation of the rotary component and deteriorates the cycle time during measurement.

  On the other hand, the contact needle measurement method according to the present embodiment uses a contact sensor. In the measurement accuracy, the measurement accuracy is lower than the air sizing measurement method according to the contact needle measurement method, but the non-circular bore which is the object in this embodiment does not deteriorate the measurement accuracy like the air sizing measurement method. Therefore, the measurement accuracy becomes high and stable. In the influence of the material, according to the contact needle measurement method, the contact needle 14 is merely brought into contact with the inner peripheral surface of the bore, and there is no influence. In the temperature influence, according to the contact needle measurement method, the contact needle 14 is merely brought into contact with the inner peripheral surface of the bore without being affected by the change in air flow, and there is no influence. In the influence of chips, according to the contact needle measurement method, there is a slight adverse effect because the contact needle 14 also contacts the chip when the contact needle 14 contacts the inner peripheral surface of the bore. In the surface roughness effect, according to the contact needle measurement method, only the contact needle 14 is brought into contact with the inner peripheral surface of the bore and there is no influence. In the measurement speed, according to the contact needle measurement method, one round is performed while detecting the cam angle θ of the cam 122 when the contact needle 14 is brought into contact with the inner peripheral surface of the bore to obtain a constant torque, so the measurement speed is somewhat slow. In the signal path, according to the contact needle measurement method, the signal path is configured by torque calculation by a cam mechanism inside the arbor, and a wired path is not required. For this reason, the rotation limit of a rotary component does not arise and the cycle time at the time of measurement does not deteriorate.

(2) The torque of the shaft motor 24 in a state where the cam angle θ of the cam 122 is set to a predetermined angle θo by the pretensioning step (step S111) and the contact needle 14 is in contact with the irregularities on the inner peripheral surface of the non-circular bore. , The cam angle θ of the cam 122 is corrected according to the reaction force (estimated reaction force Fe) from the contact needle 14 output to the torque of the shaft motor 24, and the cam angle θ of the cam 122 is set to a predetermined value. The second rotary encoder 241 and the first rotary encoder 252 are used by displacing from the angle θo and causing the contact needle 14 to make one round along the inner peripheral surface of the non-circular bore by the synchronous control rotation process (step S112). Thus, the displaced cam angle θ of the cam 122 in one round of the non-circular bore is specified.
According to the present embodiment, by using the reaction force (estimated reaction force Fe) from the contact needle 14 that is output as the torque of the shaft motor 24, extra parts are used to specify the cam angle θ that the cam 122 has displaced. The number of parts can be reduced. Thereby, since it is a simple structure, it can manufacture at low cost.

(3) The torque of the shaft motor 24 in a state where the cam angle θ of the cam 122 is set to a predetermined angle θo by the pretensioning step (step S111) and the contact needle 14 is in contact with the irregularities on the inner peripheral surface of the non-circular bore. Is controlled to calculate the reaction force (estimated reaction force Fe) from the contact needle 14 by subtracting the mechanical mechanism resistance force Fm from the load force Fl based on the torque Tl of the shaft motor 24. A constant force Fwo corresponding to the reaction force when the cam angle θ of the cam 122 is the predetermined angle θo is subtracted from the force (estimated reaction force Fe) and then converted to calculate the reaction force corresponding angle θco of the cam angle of the cam 122. Then, the calculated reaction force corresponding angle θco is added to the predetermined angle θo, and the cam angle of the cam 122 is displaced based on an angle command which is a correction angle θam obtained by adding the reaction force corresponding angle θco to the predetermined angle θo, and synchronous control is performed. By rotating the contact needle 14 once along the inner peripheral surface of the non-circular bore by the rolling process (step S112), one round of the non-circular bore is performed using the second rotary encoder 241 and the first rotary encoder 252. The cam angle θ of the displaced cam 122 is specified.
According to the present embodiment, the reaction force (estimated reaction force Fe) from the contact needle 14 can be calculated with high accuracy by subtracting the mechanical mechanism resistance force Fm from the torque of the shaft motor 24. For this reason, the displaced rotation angle θ of the cam 122 corrected according to the reaction force (estimated reaction force Fe) can be specified with high accuracy, and high-accuracy measurement can be realized.

(4) The cam motor 121 of the cutting bit 13 is rotated by the shaft motor 24 to change the protruding amount of the cutting bit 13, and the non-round bore is machined using the second rotary encoder 241 and the first rotary encoder 252. .
According to the present embodiment, the rotary drive mechanism 20, the shaft motor 24, the second rotary encoder 241, and the first rotary encoder 252 use the same components for processing the non-round bore and measuring the non-round bore shape. The number of parts can be reduced. Thereby, since it is a simple structure, it can manufacture at low cost.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements and the like within a scope that can achieve the object of the present invention are included in the present invention.

  In the present embodiment, the contact needle 14 is provided separately from the cutting tool 13. However, the contact needle 14 may not be provided separately from the cutting bit 13, and the cutting bit 13 may also serve as the contact needle and be the same part. According to this, the number of parts can be reduced by using a non-round hole drilling apparatus having exactly the same configuration for processing a non-round bore and measuring a non-round bore shape. Therefore, since it is a simple structure, it can be manufactured at low cost.

1. Non-round hole drilling device (non-round bore shape measuring device)
13 ... Cutting tool (bore processing tool)
14 ... Contact needle 20 ... Rotation drive mechanism (spindle mechanism)
24 ... Shaft motor (servo motor)
121 ... Cam (cam mechanism of bore processing tool)
122 ... Cam (cam mechanism)
241 ... Second rotary encoder (servo motor encoder)
252 ... 1st rotary encoder (encoder for spindle mechanism)

Claims (5)

Non-circular bore shape measuring device that measures non-circular bore shape is
A cam mechanism inserted into the non-circular bore;
A servo motor connected to the cam mechanism and rotating the cam mechanism;
An encoder for a servo motor that detects a rotation angle of the cam mechanism;
A rotating spindle mechanism that holds a contact needle that can project and retract on the outer peripheral surface by rotating the cam mechanism;
A spindle mechanism encoder for detecting a rotation angle of the spindle mechanism;
A pre-tensioning step for controlling the torque of the servo motor to be constant and pre-tensioning the contact needle through the cam mechanism;
A synchronous control rotation step of rotating the cam mechanism and the spindle mechanism by synchronous control,
The cam angle of the cam mechanism is displaced by constant control of the torque of the servo motor while the contact needle is in contact with the irregularities of the inner peripheral surface of the non-circular bore by the pre-tensioning process, and the synchronization is performed. By rotating the contact needle once along the inner peripheral surface of the non-circular bore by a controlled rotation step, the servo needle and the spindle mechanism encoder are used in one turn of the non-circular bore. A non-circular bore shape measuring method, wherein a cam angle displaced by the cam mechanism is specified and the non-circular bore shape is measured.   The cam angle of the cam mechanism is set to a predetermined angle by the pre-tensioning process, and the torque of the servo motor is controlled to be constant while the contact needle is in contact with the unevenness of the inner peripheral surface of the non-circular bore. The cam angle of the cam mechanism is corrected according to the reaction force from the contact needle output to the torque of the servo motor, the cam angle of the cam mechanism is displaced from the predetermined angle, and the synchronous control rotation step By causing the contact needle to make one round along the inner circumferential surface of the non-circular bore, the cam mechanism on the first round of the non-circular bore can be obtained using the servo motor encoder and the spindle mechanism encoder. 2. The non-circular bore shape measuring method according to claim 1, wherein the displaced cam angle is specified.   The cam angle of the cam mechanism is set to a predetermined angle by the pre-tensioning process, and the torque of the servo motor is controlled to be constant while the contact needle is in contact with the unevenness of the inner peripheral surface of the non-circular bore. The reaction force from the contact needle is calculated by subtracting the mechanical mechanism resistance force from the torque of the servo motor, and corresponds to the reaction force when the cam angle of the cam mechanism is a predetermined angle from the calculated reaction force. After subtracting the constant force to be converted, a reaction force corresponding angle of the cam angle of the cam mechanism is calculated, the calculated reaction force corresponding angle is added to the predetermined angle, and the cam angle of the cam mechanism is The servo motor is displaced according to a correction angle obtained by adding the reaction force corresponding angle to a predetermined angle, and the contact needle is rotated once along the inner peripheral surface of the non-circular bore by the synchronous control rotation step. For encoder The method for measuring a non-circular bore shape according to claim 1 or 2, wherein a displaced cam angle of the cam mechanism in one round of the non-circular bore is specified using an encoder for a spindle mechanism. . The spindle mechanism has a bore processing tool that can project and retract on an outer peripheral surface by rotating a cam mechanism;
The cam mechanism of the bore working tool is rotated by the servo motor to change the protrusion amount of the bore working tool, and the non-circular bore is machined using the servo motor encoder and the spindle mechanism encoder. The non-circular bore shape measuring method according to any one of claims 1 to 3. A cam mechanism inserted into the non-circular bore;
A servo motor connected to the cam mechanism and rotating the cam mechanism;
An encoder for a servo motor that detects a rotation angle of the cam mechanism;
A rotating spindle mechanism that holds a contact needle that can project and retract on the outer peripheral surface by rotating the cam mechanism;
An encoder for a spindle mechanism for detecting a rotation angle of the spindle mechanism;
The torque of the servo motor is controlled to be constant, the contact needle is pretensioned via the cam mechanism, the cam mechanism and the spindle mechanism are rotated by synchronous control, and the inner peripheral surface of the non-circular bore is The cam angle of the cam mechanism is displaced by constant control of the torque of the servo motor while the contact needle is in contact with the unevenness, and the contact needle is moved along the inner peripheral surface of the non-circular bore by 1 Measurement by measuring the shape of the non-circular bore by specifying the displaced cam angle of the cam mechanism in one round of the non-circular bore using the servo motor encoder and the spindle mechanism encoder. Means for measuring a non-circular bore shape.

Images