JP5646251B2 - Internal surface processing tool and internal surface processing device - Google Patents

Description

The present invention relates to an inner diameter surface machining tool and an inner diameter surface machining apparatus , and more particularly to an inner diameter surface machining technique particularly suitable for finishing a small-diameter workpiece hole inner diameter surface of a workpiece.

  For inner surface machining that finishes the inner diameter surface of a workpiece (hereinafter referred to as a workpiece), for example, honing for finishing the inner surface of a workpiece into a mirror surface, a honing tool is attached to the tip of the rotating spindle of the honing machine. The honing tool and the workpiece are placed in a relatively floating state, and the honing tool is rotated and reciprocated, and the honing tool grindstone is expanded by the wedge or cone of the expansion rod, and the workpiece inner surface is precisely finished. I do.

  By the way, in the honing process, as shown in FIG. 13A, the grindstones a, a,... Are always in contact with the work hole inner diameter surface Wa of the workpiece W, and this is shown in FIG. As shown in b), in a grinding process in which a rotating grindstone (grinding wheel) b is used as a machining part, the grinding wheel b is contrasted with the work surface Wb of the workpiece W in only one rotation for a moment.

  As described above, in the honing process in which the grindstones a, a,... Are always in contact with the bore diameter surface Wa of the workpiece W, there is a situation in which chips are not easily discharged from the grindstone surface g.

  For example, FIG. 13C shows a case where the cutting amount of the grindstones a, a,... With respect to the workpiece W is small in the honing process, but when the cutting amount is small as described above, the grindstone surface g of the grindstone a. There is a gap d between the workpiece W and the work hole inner diameter surface Wa of the workpiece W, and this gap d becomes a passage for discharging the chips e.

  Furthermore, when the cutting depth of the grindstones a, a,... With respect to the workpiece W is increased, the gap d for discharging the chips e becomes narrower, and accordingly, the cutting fluid that assists the discharge of the chips e becomes difficult to flow in. For this reason, the chips e are not discharged from between the grinding wheel surface g and the bore diameter surface Wa to be machined, but adhere to the abrasive grains h on the grinding wheel surface g, thereby further narrowing the gap d. As a result, the heat generated by the cutting becomes difficult to escape and the honing accuracy is deteriorated. This is because the abrasive grain h becomes fine (the abrasive grain size is small), and the processing state is further severed.

  In this regard, a honing technique as disclosed in Patent Document 1 and Patent Document 2 is known. These honing techniques are configured such that a honing tool simultaneously performs a rotational motion and a reciprocating motion, and in addition to these motions, is ultrasonically excited and vibrates at a natural frequency.

  The ultrasonic vibration applied to the honing tool not only increases the amount of material removal compared to the conventional case, but also enables a good shape correction of the hole.

6-506157 Special table flat 7-50259

  By the way, in the conventional honing technique disclosed in Patent Document 1 and Patent Document 2, the vibrator is configured to be arranged in a direction in which the honing tool is desired to vibrate. However, it is difficult to apply ultrasonic vibration when the workpiece diameter to be processed is small. There wasn't.

  That is, the vibrations in these conventional honing techniques include an axial component and a radial component, both of which are affected by the natural frequency, and the latter radial direction compared to the former axial component. The component is small (inefficient), and the radial component of this vibration is not enough to actively use it as a cutting motion as well as adjusting the finished dimensions, and there is no such technical idea It was.

  Further, in these conventional honing techniques, the design conditions such as the tool length and shape dimensions of the honing tool are severe due to many constraint conditions, and there is room for further improvement in practice from this point of view.

  The present invention has been made in view of such conventional problems, and the object of the present invention is to increase the machining efficiency of the inner surface of the hole to be machined by widening vibration in the radial direction of the grindstone. It is an object to provide an inner surface processing technique capable of realizing the above.

In order to achieve the above object, an inner diameter surface processing tool of the present invention is attached to a spindle of a machine tool or the like and processes a work hole inner diameter surface of a workpiece. A grindstone processing part that is provided in a part and has a structure that widens and vibrates in the radial direction by axial vibration, and vibration applying means that applies axial vibration to the tool main body, and the lower end of the tool main body includes the above A weight portion that functions as a weight of the grindstone processing portion is provided, and a grindstone portion that has at least a radial outward deflection characteristic is provided above the weight portion to constitute the grindstone processing portion, and the vibration application Due to the cooperative action of the axial vibration of the tool body by means and the weight action of the weight part, the grindstone part bends radially outward and widens and vibrates .

The following configuration is adopted as a preferred embodiment.
(1) The vibration applying means is an ultrasonic vibrator integrally connected to the base end of the tool body.

( 2 ) The weight portion is made of a material having a specific gravity (density) larger than at least the constituent material of the grindstone portion.

( 3 ) The grindstone portion is provided with a plurality of widening slits in a hollow cylindrical body continuous with the outer circumference of the cylinder of the tool main body to form a hollow grindstone main body, and abrasive grains on the outer circumferential surface of the grindstone main body. Is electrodeposited.

( 4 ) The grindstone portion has a hollow grindstone body formed by arranging a plurality of thin metal plates on a cylindrical contour along the outer peripheral portion of the tool main body. The grains are electrodeposited.

Further, the inner surface processing apparatus of the present invention includes the above-mentioned inner surface processing tool attached to the main shaft as a processing tool, and the grinding wheel processing portion of the processing tool is vibrated in the radial direction by the vibration applying means. An inner surface processing apparatus for finishing an inner surface of a hole to be machined of a workpiece , wherein the vibration applying means includes an ultrasonic vibrator integrally connected to a base end of the tool body, and the ultrasonic vibrator Is arranged in the main shaft, and has a configuration for adjusting the amplitude amount of the widening vibration of the grindstone processing part in-process by controlling the operation of the ultrasonic vibrator during processing, and is adjusted in the in-process. An amplitude amount of the widening vibration of the grindstone processing portion is a grindstone wear amount .

Further, the inner surface processing apparatus of the present invention includes the above-mentioned inner surface processing tool attached to the main shaft as a processing tool, and the grinding wheel processing portion of the processing tool is vibrated in the radial direction by the vibration applying means. An inner surface processing apparatus for finishing an inner surface of a hole to be machined of a workpiece, wherein the vibration applying means includes an ultrasonic vibrator integrally connected to a base end of the tool body, and the ultrasonic vibrator Is arranged in the main shaft, and has a configuration for adjusting the amplitude amount of the widening vibration of the grindstone processing part in-process by controlling the operation of the ultrasonic vibrator during processing, and is adjusted in the in-process. The amplitude amount of the widening vibration of the grindstone processing portion is an amplitude amount for adjusting the machining dimension.

And as a suitable embodiment, the following composition is adopted.
( 1 ) The power supply to the ultrasonic transducer is non-contact power feeding.

( 2 ) The main shaft, which is a rotary main shaft that is reciprocally movable in the axial direction of the inner diameter surface of the hole to be processed of the workpiece, and is rotatably supported around the axis, and the rotary main shaft is driven to rotate about the axis. Main shaft rotating means, main shaft reciprocating means for reciprocating the rotating main shaft in the axial direction of the inner surface of the hole to be machined, and control means for automatically controlling the operations of the main shaft rotating means and the main shaft reciprocating means in conjunction with each other. It is equipped with.

  According to the present invention, as a processing tool attached to a main shaft of a machine tool or the like, a grindstone processing portion having a structure that widens and vibrates in a radial direction due to axial vibration of the tool main body is provided in a part of the tool main body. By applying axial vibration to the main body, the grindstone processing section is vibrated in the radial direction to process the inner surface of the work hole. When axial vibration is applied to the tool main body, this axial vibration is applied. Thus, the grinding wheel processing portion vibrates in the radial direction, and this is used for the cutting motion, whereby mechanical removal processing with radial vibration can be performed on the inner surface of the workpiece hole.

  That is, according to the present invention, for example, the axial vibration of the ultrasonic wave can be efficiently converted as the widening vibration in the radial direction of the grindstone machining portion, and the machining efficiency in the inner surface machining such as honing is improved. be able to. The occurrence of large vibrations in the tool radial direction in such a machining tool brings about new progress in the precision machining technology of the inner surface of the hole to be machined.

  In other words, when the grindstone processing part vibrates in the radial direction, the grindstone processing part cuts into the work hole inner diameter surface of the workpiece, and the gap between the two becomes narrow, or the grindstone processing part becomes covered with the work. As a result of repeating the operation between these two states, the clearance between the two is increased away from the inner diameter surface of the machining hole, the cutting oil easily enters the gap and is discharged by the pump action generated here. In this way, the chip discharging property is improved.

  Thereby, since the cutting resistance at the time of inner surface machining does not increase excessively, the machining time is shortened by setting the cutting amount of the grindstone machining part large. Moreover, since the cutting force is small for thin-walled workpieces, highly accurate drilling with less distortion is possible.

It is a side view which shows the honing machine which is Embodiment 1 which concerns on this invention. It is front sectional drawing which shows the honing tool which is the main components of the honing machine. It is a front view which shows the tool main body of the honing tool. FIG. 4A is a front view showing the grindstone processing portion of the tool body in an enlarged manner, FIG. 4A shows a normal state, and FIG. 4B shows a wide state. It is a figure which shows typically the relationship between the structure of the honing tool, and an ultrasonic vibration mechanism. FIG. 6A is an enlarged schematic diagram showing a grindstone processing portion of the tool body, FIG. 6A is a state at the time of widening, FIG. 6B is a state at a normal state, and FIG. Respectively. It is a schematic diagram which expands and shows the modification of the grindstone processing part of the tool main body. It is an outline figure which shows the kind of cross-sectional outline shape at the time of the widening of the honing grindstone (grindstone part) of the tool main body. FIG. 9 (a) is a diagram schematically showing the relationship between the grinding wheel surface of the honing tool grinding portion and the work hole inner diameter surface of the workpiece. FIG. 9 (a) shows a narrow cutting gap due to the grinding stone surface of the honing tool grinding portion. FIG. 9B shows a state in which the notch gap is widened. FIG. 10A is a scanning electron micrograph of the finished surface of the work inner diameter surface of the workpiece by the honing tool, and FIG. 10B is a comparison with the finished surface of the work inner diameter surface of the workpiece by the conventional honing tool. It is a scanning electron micrograph shown. It is a graph which compares the finishing surface roughness of the to-be-processed internal-diameter surface of the workpiece | work by the same honing tool with the finishing surface roughness of the to-be-processed internal diameter surface of the workpiece | work by the conventional honing tool. It is a front view which shows the grindstone processing part of the tool main body of the honing tool which concerns on Embodiment 2 of this invention, Fig.12 (a) shows the state at the time of a normal state, FIG.12 (b) shows the state at the time of widening. FIG. 13A is a schematic diagram showing the relationship between the grindstone in the honing process and the bore diameter surface of the workpiece, and FIG. 13B is a schematic diagram showing the relationship between the grindstone in the grinding process and the workpiece surface of the workpiece. FIG. 13C is a diagram schematically showing the relationship between the grindstone surface of the grindstone portion and the bore diameter surface of the workpiece to be machined in the honing process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, the same reference numeral indicates the same component or element.

  FIG. 1 shows an inner surface processing apparatus according to the present invention. Specifically, this inner surface processing apparatus hones the inner diameter surface of a work hole Wa having a small diameter of the workpiece W (in the illustrated case, an inner diameter of about 4.0 mm). A honing machine to be machined, and a honing tool (inner diameter surface machining tool) 1 that is a characteristic configuration of the present invention as a machining tool is provided at the tip of the rotary spindle 2, and the honing tool 1 is a grindstone as a grindstone cutting portion. The work hole inner diameter surface Wa of the workpiece W is subjected to honing finish processing while being vibrated in the radial direction by the vibrating portion 3.

  The honing machine has a conventionally known basic structure in addition to the above configuration. That is, the honing machine can be reciprocated in the axial direction of the work hole inner diameter surface Wa of the workpiece W, and is supported by the rotary main shaft 2 that is rotatably supported around the axis. Mainly includes a main shaft rotation drive unit (main shaft rotation means) 4 that rotates around the axis, and a main shaft reciprocation drive unit (main shaft reciprocation means) 5 that reciprocates the rotation main shaft 2 in the axial direction of the bore diameter surface Wa of the workpiece W. These main parts are mounted on a column 7 which is a main body of the apparatus, and the main shaft rotation driving unit 4 and the main shaft reciprocating driving unit 5 are interlocked with each other by a device control unit (control means) 6. It is configured to be driven and controlled.

  In addition, the workpiece W floats in the horizontal direction on the workpiece holding jig 8 of the workpiece holding portion (back and forth and left and right directions) with the axis of the cylindrical inner diameter surface Wa, which is the inner diameter surface of the hole to be processed, facing upward and downward. It is supported so that it can be removed and replaced.

  The rotation spindle 2 includes the honing tool 1 at the tip, that is, the lower end thereof, the spindle rotation drive unit 4 including the spindle drive shaft 10, the power transmission units 11a to 11c, the drive motor 12, and the like, the slide body 15, the feed screw. The main shaft reciprocating drive unit 5 including the mechanism 16, the drive motor 17 and the like is linked to each other.

  That is, the rotary main shaft 2 is rotatably supported by a slide main body 15. The slide main body 15 is guided up and down by a guide rail (not shown), and is driven by the feed screw mechanism 16 that is an up-and-down drive source. The main shaft reciprocating drive unit 5 is configured to be drivingly connected to the motor 17.

  Although not specifically shown, the guide rail is provided on the machine body 19 so as to extend linearly in the vertical direction, and the sliding portion 15a of the slide body 15 is supported by the guide rail so as to be able to slide. Yes. Further, a nut body 16a of a feed screw mechanism 16 is integrally connected and fixed to the sliding portion 15a of the slide body 15, and this nut body 16a extends in the vertical direction in the vertical direction and is rotatably supported by the machine body 19. The feed screw 16b is screwed so as to be able to advance and retract in the vertical direction. An upper end portion of the feed screw 16 b is drivingly connected to the motor shaft 17 a of the driving motor 17 through the coupling 20. As the drive motor 17, a servo motor integrally including a position detection sensor 21 such as a rotary encoder is used, and the rotation amount of the drive motor 17 is detected by the position detection sensor 21.

  When the motor shaft 17a of the drive motor 17 is rotationally driven, the feed screw 16b of the feed screw mechanism 16 is rotated, and the slide body 15 integral with the nut body 16a is moved in the vertical direction. The rotary main shaft 2, that is, the honing tool 1 is moved up and down via. Further, the hoisting / lowering operation of the honing tool 1 is detected by the position detection sensor 21 built in the drive motor 17 and the detection result is sent to the apparatus control unit 6 described later.

  Further, the upper end portion 2 b of the rotation main shaft 2 is drivingly connected to the main shaft rotation drive unit 4. That is, the upper end portion 2 b of the rotary spindle 2 is spline-fitted to the spindle drive shaft 10 that is rotatably provided on the head portion 19 a of the machine body 19, and the vertical direction (axial direction) with respect to the spindle drive shaft 10. It is relatively movable and connected to be integrally rotatable.

  Specifically, the upper end portion 2b of the rotary main shaft 2 is pivotally supported by the rotary spline device 22 on the head portion 19a of the machine body 19 so as to be slidable in the vertical direction, and is coaxial with the main shaft drive shaft 10 and It is connected so that it can rotate integrally.

  A transmission pulley 11a is attached to the main shaft drive shaft 10, and this transmission pulley 11a is connected to a transmission pulley 11c attached to the motor shaft 12a of the drive motor 12 via a transmission belt 11b. As the drive motor 12, a servo motor in which a position detection sensor 23 such as a rotary encoder is integrated is used, and the rotation amount of the drive motor 12 is detected by the position detection sensor 23. The rotational motion of the honing tool 1 is detected.

  Then, by the rotational drive of the drive motor 12, the rotary spindle 2, that is, the honing tool 1 is rotationally driven via the spindle drive shaft 10. Further, the rotation operation of the honing tool 1 is detected by the position detection sensor 23 built in the drive motor 12, and the detection result is sent to the device control unit 6 described later.

  As shown in FIG. 2, the honing tool 1 includes a tool main body 30, a grindstone processing unit 31 that vibrates in the radial direction, and an ultrasonic vibrator 32 that constitutes a vibration applying unit as main parts, and an attachment unit 33. Accordingly, the front end mounting portion 2a of the rotary main shaft 2 is mounted and fixed in a replaceable manner. In addition, when the honing tool 1 is mounted, the ultrasonic transducer 32 is housed and disposed in the distal end hollow portion 2 c of the rotating main shaft 2.

  Specifically, the tool main body 30 is in the form of a linear metal rod having a diameter smaller than the inner diameter surface Wa of the workpiece W to be processed, and a weight portion 35 is provided at the tip, that is, the lower end. In addition, a plurality of (four in the illustrated example) honing grindstones 36, 36,... Constituting the grindstone portion are provided above the weight portion 35, and the weight portion 35 and the honing grindstones 36, 36,. The grindstone processing unit 31 is configured.

  In the illustrated embodiment, a hollow cylindrical body 36A constituting the honing grindstones 36, 36,... Is integrally fitted and connected to the tip 30a of a solid columnar tool body 30, and this hollow cylindrical body is further connected. The solid columnar weight portion 35 is integrally fitted and connected to the lower side of 36A, and these three members 30, 36A and 35 are connected coaxially and linearly.

  As shown in FIG. 4, the honing grindstones 36, 36,... Have a plurality of (four in the illustrated example) widening slits 37, 37 in the hollow cylindrical body 36 </ b> A continuous with the cylindrical outer periphery of the tool body 30. Are provided to form a hollow grindstone main body (grinding wheel base), and a large number of minute abrasive grains 38 are electrodeposited on the outer peripheral surface of the grindstone main body. Thus, a plurality of honing grindstones 36, 36,... Are arranged at equal intervals in the circumferential direction (four in the illustrated example).

  Superabrasive grains such as CBN abrasive grains and diamond abrasive grains can be suitably used as the abrasive grains constituting the honing grindstone 36, and the honing grindstone 36 of this embodiment is a CBN formed by electrodeposition of CBN abrasive grains. An electrodeposition grindstone is used.

  The specific configuration of the honing grindstone 36 is not particularly limited as long as it satisfies the conditions described later (at least radial outward deflection characteristics). For example, the abrasive grains 38 may be a bonding means other than electrodeposition. A structure adhered to the outer peripheral surface of the hollow cylindrical body 36A can also be employed.

  The weight portion 35 has a weight effect on the honing grindstones 36, 36,..., And is made of a material having a specific gravity (density) larger than that of the constituent materials of the honing grindstones 36, 36,. , 36,... Are at least radially outwardly (both radially outwardly and inwardly in this embodiment) structured (easy to bend), and the weight 35 and the honing grindstone 36, The grindstone processing part 31 having a structure that vibrates in the radial direction by axial vibration is constituted by the combined structure with.

  In addition, since the said weight part 35 functions also as a pilot guide part which guides the tool main body 30 in the to-be-processed hole Wa of the workpiece | work W, the diameter dimension inevitably has the outer diameter of the honing grindstones 36, 36, ... Since it is designed to be smaller than the dimensions, it is important that the weight portion 35 is made of a material having a relatively large specific gravity (density) also in this respect.

  The material of the tool body 30, the hollow cylindrical body 36A constituting the grindstone body of the honing grindstone 36, and the weight portion 35 are axial vibrations of the tool body 30 by the ultrasonic vibrator 32, that is, vertical vibrations, as will be described later. And the weight action of the weight portion 35, considering the material characteristics, particularly the specific gravity (density), so that the honing grindstones 36, 36,... Selected and adopted.

  In relation to this, a tool holder 45 is integrally fixed to a base end portion of the tool body 1 by a fixing means 46 such as a brazing, and a connection bolt 45 a of the tool holder 45 is connected to the ultrasonic transducer 32. The tool body 30 and the ultrasonic transducer 32 are coaxially and integrally fixed by being screwed and fixed to the tip 40a of the first horn 40. Further, although not specifically shown, the tool body 1 and the tool holder 45 may have a cut-out integrated structure.

  Referring to FIG. 5, when an AC voltage having a frequency equal to the resonance frequency of the tool body 30 that is a vibration system is applied to the piezo elements 41, 41,. The sound wave oscillator 32 resonates in the axial direction. On the other hand, the vibrating body including the tool holder 45, the tool main body 30, the grindstone portion 36, and the weight portion 35 vibrates axially at the same frequency by excitation by the ultrasonic transducer 32.

  In normal resonance vibration, if the vibrating body has a uniform rod shape and the material is uniform, for example, the vibration amplitude distribution at the tip of the vibrating bodies 45, 30, 36 and 35 in FIG. Draw a rising curve like a sine wave like the distribution shown.

  However, the vibrating bodies 45, 30, 36, and 35 of the present embodiment are made of a cemented carbide or the like in which the weight portion 35 at the tip portion has a large specific gravity (density), and the grindstone portions 36, 36,. With this configuration, the amplitude of the vibration distribution decreases at the weight portion 35 at the tip as shown by the solid line in the upper part of FIG.

  At this time, the honing grindstones 36, 36,..., Which have low rigidity and have a characteristic of bending outward in the radial direction (in the present embodiment, radially outward and inward), are affected by the axial vibration. Will be converted into flexural vibration. The solid line shown in the lower part of FIG. 5 is an amplitude distribution diagram obtained by measuring the amplitude in the radial direction, and shows the diametrically outward amplitude that is prominently protruded with the low-stiffness honing grindstones 36, 36,. The amplitude of this radial vibration is proportional to the amplitude of the ultrasonic transducer 32 that generates axial vibration. Therefore, by accurately controlling the AC voltage that drives the ultrasonic transducer 32, it is possible to accurately convert the amplitude of the honing grindstones 36, 36,...

  That is, the ultrasonic vibrator 32 resonates and vibrates in the axial direction, so that the vibrating body including the tool holder 45, the tool main body 30, the grindstone portion 36, and the weight portion 35 also vibrates axially at the same frequency as the ultrasonic vibrator 32. In this case, however, the honing grindstones 36, 36,... Are low in rigidity and have at least a radially outward bending characteristic (in the present embodiment, radially outward and inward). A weight 35 having a large specific gravity (density) is connected to the front end side (lower end side) of the honing grindstones 36, 36,..., So that vibration force in the axial rear end (upper end) direction is applied. The honing grindstones 36, 36,... Maintain the normal state shown in FIG. 4A (outer diameter = D0). On the contrary, when a vibration force in the axial tip (lower end) direction is applied, the honing grindstone 36 is maintained. , 36, etc. remain normal Can not be deflected to flex radially outwardly (outer diameter = D1) or inner (present embodiment). In the present embodiment, the honing grindstones 36, 36,... Are radially outward and inwardly bent outward (FIG. 6B) centering on the state shown in FIG. 6B (FIG. 4A). (A)) and inward (FIG. 6 (c)) are equally increased or decreased with equal amplitude.

  That is, the honing grindstones 36, 36,... Bend radially outward and widen by the cooperative action of the axial vibration of the tool body 30 by the ultrasonic vibrator 32 and the weight action of the weight portion 35, and widening vibration. Will do. And 1/2 of the difference D1-D0 of the outer diameter D1 at the time of bending and the outer diameter D0 at the normal state is the cutting amount of the honing grindstones 36, 36,.

  In order for the honing grindstones 36, 36,... To exhibit their intended effects, at least the honing grindstones 36, 36,... Must have at least a radially outward deflection characteristic. As described above, the honing grindstones 36, 36,... Of the present embodiment have a structure that has a characteristic of bending outward and inward in the radial direction (FIGS. 6A, 6B, 6). c)).

  Thereby, the honing grindstones 36, 36,... Of the present embodiment are regularly and regularly operated in the radially outward and inward bending (widening / shrinking) operations, that is, the widening / shrinking operations. Consider the structural conditions.

  Referring to FIG. 4, the honing grindstones 36, 36 are structural conditions for the regular enlargement (+) and contraction (−) of the outer diameter of the honing grindstones 36, 36,. The hollow cylindrical body 36A constituting the grindstone main body (grindstone base) is a parallel pipe shape, that is, a straight cylindrical shape, and the number of divisions of the hollow cylindrical body 36 by the widening slits 37, 37,. it is conceivable that.

  For example, as shown in FIG. 7, when the hollow cylindrical body 36A is not parallel and is curved in an extremely bulging shape radially outward, the outer diameter of the honing grindstones 36, 36,. Even if (+) and normal state (0) are repeated (single amplitude motion) or reduced (−), the value is very small, and it seems that equal amplitude motion cannot be obtained.

  In addition, even when the widening slits 37, 37,... Have a small width and the number of divisions of the hollow cylindrical body 36 is small, the same phenomenon as described above occurs, and in addition, it seems that a large amplitude cannot be obtained. On the other hand, when the number of divisions of the hollow cylindrical body 36 is large, a plurality of vibration nodes appear due to insufficient rigidity of the honing grindstones 36, 36,... (See, for example, FIGS. 8B and 8C). ), It has been experimentally found out of control.

  When the hollow cylindrical body 36A constituting the grindstone main body (grindstone base) of the honing grindstones 36, 36,... Is a parallel pipe, and the number of divisions of the hollow cylindrical body 36 is appropriate, the acceleration reaching 20,000 g. When this occurs, an overrun phenomenon occurs at the timing when the honing grindstones 36, 36,... Extend in the axial direction and the deflection becomes neutral, and the axial reduction process starts again at that moment. Deflection occurs in the overrun direction opposite to the reduction stroke, and in order to repeat this, instead of the single amplitude as described above, regular (+), (+) like the honing grindstones 36, 36,. It is considered that the vibration (-amplitude motion) of −) occurs in the radial direction.

  In this embodiment, the honing grindstones 36, 36,... Have a double-amplitude structure. However, depending on the purpose, the hollow cylinder that forms the grindstone main body (grindstone base) of the honing grindstones 36, 36,. By changing the design of the body 36A, the honing tool 1 including the single amplitude type honing grindstones 36, 36,... Can be manufactured.

  Moreover, about the cross-sectional outline shape at the time of the widening of the honing grindstone 36,36, ..., as shown in FIG. 8 (a), (b) or (c) by adjusting the thickness dimension of the hollow cylindrical body 36A. To change. Incidentally, the contour shape of FIG. 8A is an ideal shape in the present embodiment, and when the thickness is further reduced, the shape as shown in FIG. 8B or FIG. 8C is obtained. . The wall thickness of the hollow cylindrical body 36A is adjusted while analyzing by the finite element method.

  Then, as in the present embodiment, the honing grindstones 36, 36,... Move radially outward as shown in FIG. 6 (a) from the normal position (outer diameter = D0) shown in FIG. 6 (b). In addition to bending (outer diameter = D1) (widening), it also bends radially inward as shown in FIG. 6C (outer diameter = D2 (D0− (D1−D0)) (reduced) When the structure is widened, as will be described later, the pump action due to repeated changes in the gap C between the state shown in FIG. 9A and the state shown in FIG. 9B is effective and significant. As a result, a large discharge effect of the chips Wc due to the smooth flow of the lubricating oil can be obtained.

  The grindstone vibrating section 3 vibrates the honing grindstones 36, 36,... Of the honing tool 1 in the radial direction as a notch, and specifically, the ultrasonic vibrator 32, the power supply section 50, and the power supply control. The part 51 is provided as a main part.

  The power supply control unit 51 controls the application timing of the AC voltage (frequency) to be applied to the ultrasonic transducer 32 and the magnitude of the AC voltage (frequency) by the power supply unit 50. Specifically, By controlling the amplitude of the ultrasonic vibrator 32 in the axial direction, the amplitude amount of the widening vibration of the honing grindstones 36, 36,. The power supply control unit 51 constitutes a part of the device control unit 6 described later.

  In the power supply control unit 51, a program for controlling the operation of the honing grindstones 36, 36,... In the honing tool 1 is incorporated in advance or can be appropriately changed. Further, by controlling the operation of the ultrasonic vibrator 32, the amplitude amount of the widening vibration of the honing grindstones 36, 36,... Is adjusted in-process. Therefore, in this embodiment, the finishing accuracy correction method for the inner diameter surface Wa of the workpiece W of the workpiece W can be realized only by electric means, and the accuracy is improved (control stability) compared to the conventional mechanical correction. And suppression of changes over time).

  Further, a non-contact power feeding method is adopted for power supply to the ultrasonic transducer 32 by the power supply unit 50.

  The device control unit 6 automatically controls the operation of each drive unit of the honing machine in conjunction with each other. Specifically, the main unit is a microcomputer including a CPU, a ROM, a RAM, an I / O port, and the like. It is configured.

  The device control unit 6 incorporates a machining program for executing honing, and includes the above-described power supply control unit 51 of the grindstone vibrating unit 3 as a constituent element.

  Thus, in the honing machine configured as described above, the grindstone vibration unit 3, the spindle rotation driving unit 4 and the spindle reciprocating driving unit 5 are automatically controlled by the device control unit 6 in relation to each other. A honing process by the honing tool 1 is performed on the work hole inner diameter surface Wa of the workpiece W supported by the holding jig 8.

  That is, according to a control program that is input or set in advance in the apparatus control unit 6, the honing tool 1 has the honing grindstones 36, 36,. As a result of the cooperative action, the workpiece is inserted into the work hole inner diameter surface Wa of the workpiece W and is rotated and reciprocated along with the operation of the rotary spindle 2 while bending and vibrating in the radial direction. Is given to the workpiece inner diameter surface Wa of the workpiece W.

  In this case, the widening vibration width of the honing grindstones 36, 36,... When the honing tool 1 is fed into the work hole inner diameter surface Wa of the workpiece W and inserted is set to be small. When the work hole inner diameter surface Wa of the workpiece W is close to the honing grindstones 36, 36,..., The honing tool 1 moves the workpiece W while the widening vibration of the honing grindstones 36, 36,. Are inserted into the inner diameter surface Wa of the processed hole.

  As described above, the honing tool 1 of the present embodiment is provided on the tool body 30 and a part of the tool body 30, and has a grindstone processing portion 31 (35, 35) having a structure that vibrates in the radial direction by axial vibration. 36) and an ultrasonic vibrator 32 that applies axial vibration to the tool body 30. When axial vibration is applied to the tool body 30 by the ultrasonic vibrator 32, the axial vibration causes the tool main body 30 to vibrate. The honing grindstones 36, 36,... Oscillate in the radial direction and can perform machining with radial vibration on the bore surface Wa of the workpiece W. That is, according to the present embodiment, the axial vibration of the ultrasonic vibrator 32 can be efficiently converted as the widening vibration in the radial direction of the honing grindstones 36, 36,. Can be made.

  That is, according to the configuration in which the honing grindstones 36, 36,... Vibrate in the radial direction as described above, it is possible to improve the chip dischargeability and increase the material removal efficiency in the honing process.

  In other words, the honing grindstones 36, 36,... Of the grindstone processing unit 31 are ultrasonically vibrated in the radial direction, so that the abrasive grains 38, 38 on the grindstone surface 36a of the honing grindstone 36 are shown in FIG. ,... Are cut into the work hole inner diameter surface Wa of the workpiece W (see FIG. 4B), and the gap C between the two 36a and Wa becomes narrower, or as shown in FIG. The abrasive grains 38, 38,... Of the grindstone surface 36a of the 36 are separated from the work hole inner diameter surface Wa of the workpiece W (see FIG. 4A), and the gap C between the both 36a, Wa is widened. As a result of repeating the operation between these two states, the cutting oil (refer to the arrow) easily enters the gap C by the pump action generated here, and is discharged, thereby improving the dischargeability of the chips Wc.

  Further, when the honing grindstones 36, 36,... Are ultrasonically vibrated in the radial direction, a large acceleration works, and the honing grindstones 36, 36,. For example, when the frequency is 44 kHz and the vibration amplitude is 3 μm, the honing grindstones 36, 36,... Have an acceleration of 20,000 times or more the gravitational acceleration.

  Thereby, since the cutting resistance at the time of the honing process does not increase excessively, the machining time is shortened by setting the cutting amount of the honing grindstones 36, 36,. Further, since the thin-walled workpiece W has a small cutting resistance, it is possible to perform highly accurate drilling with less distortion.

  The honing machine of the present embodiment can provide the following effects regardless of whether it is used for the final finishing process or the roughing process.

(1) When used in the final finishing process:
(A) By applying ultrasonic vibration to the honing tool 1, the surface roughness of the work hole inner diameter surface Wa of the workpiece W is good even if the grits 38 and 38 of the grindstone surface 36 a of the honing grindstone 36 are the same. Finished.

  In other words, since the slightly rough abrasive grains 38, 38,... Can be used on the grindstone surface 36a of the honing grindstone 36, the effect is that the grindstone surface 36a of the honing grindstone 36 and the bore diameter of the workpiece W in the workpiece W are as follows. A sufficient gap C can be secured between the surface Wa and the chip Wc can be discharged well. As a result, the cutting amount of the honing grindstones 36, 36,... Can be increased and the machining time can be shortened.

(B) Since the work hole inner diameter surface Wa of the workpiece W has an equally spaced pattern due to ultrasonic vibration as shown in FIG. When used as a lubricant, lubricating oil accumulates in the grooves forming these patterns, and a uniform and stable sliding resistance reduction effect can be expected.

  Incidentally, in machining that does not involve normal ultrasonic vibration, an irregularly raised pattern as shown in FIG. 10B is formed on the inner diameter surface Wa of the workpiece W, and a large amount of chips remain. The surface becomes rough.

(C) In addition, as shown in FIG. 11, the finished surface roughness of the work hole inner diameter surface Wa of the workpiece W is honing that does not involve normal ultrasonic vibration in the honing processing with ultrasonic vibration according to the present embodiment. It is as good as 1/2 times the processing.

(2) When used in roughing process:
(A) In the roughing process, the smaller the variation in the diameter of the prepared hole, the more stable the machining time and the shorter the machining time.

  That is, as an adverse effect caused by the variation in the diameter of the prepared hole, the larger the variation, the greater the amount of air cut in which the honing grindstones 36, 36,... Do not contact the bored surface Wa of the workpiece W (the honing grindstones 36, 36). ,... Need to be released from the inner surface Wa of the workpiece W of the workpiece W), which increases the air cut time and the machining time.

  On the other hand, when the air cut amount is reduced, the honing grindstones 36, 36,... Immediately come into contact with the bore diameter surface Wa of the workpiece W and the honing tool 1 is broken or the honing grindstones 36, 36,. The cutting amount of the honing grindstones 36, 36,... Immediately after the start of machining is generally large in order to shorten the machining time, even if the hole diameter error occurs. It is set to be able to process somehow even if there is.)

  In this regard, as in the present embodiment, even if the prepared hole inner diameter surface Wa of the workpiece W varies by applying ultrasonic vibration to the honing tool 1, the grindstone surface 36a of the honing grindstone 36 varies. It is unlikely that the workpiece W is immediately brought into contact with the work hole inner diameter surface Wa and the honing tool 1 is damaged or the honing grindstones 36, 36,.

(B) In general, immediately after the honing process is started, the work hole inner diameter surface Wa of the workpiece W does not hit the entire surface of the honing grindstone 36, so the processing load tends to be low (there is a lot of space for the chips Wc to escape).

  In this regard, since the honing tool 1 of the present embodiment is in contact with the bore diameter surface Wa of the workpiece W by ultrasonic vibration, if the hole diameter of the bore diameter surface Wa of the workpiece W is smaller than expected, The amplitude amount of the honing grindstones 36, 36,... Is limited, and the amount of bending is reduced. Therefore, the honing tool 1 is hardly damaged.

  By electrically controlling the expansion amount of the honing grindstones 36, 36,..., The finished diameter of the work hole inner diameter surface Wa of the workpiece W can be adjusted in-process. In this case, there are two types of methods for adjusting the amount of expansion of the honing grindstones 36, 36,...

  In this case, the amplitude amount control of the honing grindstones 36, 36,... During the honing process is the same concept as the conventional method of pushing and cutting the wedge. For example, during the honing process, the amplitude amount of the honing grindstones 36, 36,... Is increased continuously in a stepless manner or in a plurality of steps. Initially, the diameter of the work hole inner diameter surface Wa of the workpiece W is small, so the amplitude is reduced. However, the amplitude is increased step by step as the hole diameter increases.

  Another way of thinking is to process as a large expansion amount (amplitude amount) from the beginning. When the hole diameter of the work hole inner diameter surface Wa of the initial workpiece W is small, the amount of expansion (deflection) is limited, and although it is small, the hole diameter is gradually increased to finish the target hole diameter.

  An ultrasonic vibrator 32 is incorporated in the rotary main shaft 2, and a tool main body 30 capable of ultrasonic vibration in the radial direction is disposed at the tip thereof, and a honing grindstone 36 for axial vibration by the ultrasonic vibrator 32, The honing tool 1 can be downsized because of its small and simple structure that converts it into radial vibrations 36,.

Embodiment 2
This embodiment is shown in FIG. 12, and the specific structure of the tool main body 30 of the first embodiment is slightly modified.

  That is, the honing grindstones 36, 36,... Of the tool main body 30 of the present embodiment include a plurality of (four in the illustrated example) thin metal plates 136 on the cylindrical contour along the outer peripheral portion of the tool main body 30. 136 are arranged at equal intervals to form a hollow grindstone main body, and abrasive grains 38, 38,... Are electrodeposited on the outer peripheral surface of the grindstone main body.

Specifically, the distal end portion 30a of the tool body 30 and the proximal end portion 35a of the weight portion 35 are connected to and fixed to these cylindrical outer peripheral surfaces in a bridging manner by four thin metal plates 136, 136,. A coaxial grindstone body is formed by the thin metal plates 136, 136,..., And is integrally connected on the same axis and in a straight line. A large number of abrasive grains 38, 38,. The honing grindstones 36, 36,... Are formed by electrodeposition. Thus, a plurality of honing grindstones 36, 36,... Are arranged at equal intervals in the circumferential direction (four in the illustrated example).
Other configurations and operations are the same as those of the first embodiment.

  In addition, Embodiment 1 and 2 mentioned above show the suitable embodiment of this invention to the last, This invention is not limited to these, A various design change is possible in the range.

  For example, the specific structure of the honing tool 1 (the honing grindstones 36, 36,..., The ultrasonic vibrator 32, etc.) can be variously modified as long as it has a similar function.

  In the illustrated embodiment, the power supply to the ultrasonic transducer 32 is a non-contact power supply method, but although not specifically illustrated, a slip ring type contact power supply method can also be used.

  In the honing machine of the illustrated embodiment, the rotating spindle 2 side rotates. However, a structure in which the workpiece holding jig 8 side rotates can also be used.

  Furthermore, the honing tool 1 can be applied to other types of precision processing machine tools such as a fine boring machine in addition to the honing machine as shown in the illustrated embodiment. As an alternative, or through an attachment, it can be applied to a general-purpose machine tool such as a machining center.

W Workpiece Wafer work hole inner diameter surface 1 Honing tool (inner diameter surface processing tool)
2 Rotating spindle 3 Grinding wheel vibration part 4 Spindle rotation drive part (spindle rotating means)
5 Spindle reciprocating drive (spindle reciprocating means)
6 Device control unit (control means)
30 Tool body 31 Grinding wheel processing section 32 Ultrasonic vibrator (vibration applying means)
35 Weight 36 Honing wheel (grinding wheel)
36A Hollow cylindrical body 37 Widening slit 38 Abrasive grain 40 First horn 41 Piezo element 42 Second horn 50 Power supply unit 51 Power supply control unit 136 Thin metal plate

Claims (9)

An inner surface machining tool that is attached to a spindle of a machine tool or the like and processes an inner surface of a workpiece to be machined,
A tool main body, a grindstone processing portion provided in a part of the tool main body and having a structure that expands and vibrates in a radial direction by axial vibration, and a vibration applying unit that applies axial vibration to the tool main body,
A weight portion that functions as a weight of the grindstone processing portion is provided at a lower end portion of the tool main body, and a grindstone portion having at least a radially outward deflection characteristic is provided above the weight portion, so that the grindstone processing is performed. Part is composed,
An inner surface machining tool characterized by the fact that the grindstone portion bends radially outward and widens and vibrates due to the cooperative action of the axial vibration of the tool body by the vibration applying means and the weight action of the weight portion. . The inner diameter surface processing tool according to claim 1 , wherein the vibration applying means is an ultrasonic vibrator integrally connected to a base end of the tool main body. 2. The inner surface machining tool according to claim 1 , wherein the weight portion is made of a material having a specific gravity larger than that of at least the constituent material of the grindstone portion. In the grindstone portion, a hollow cylindrical body continuous with the outer circumference of the tool body is provided with a plurality of widening slits to form a hollow grindstone body, and abrasive grains are electrodeposited on the outer circumferential surface of the grindstone body. The inner diameter surface processing tool according to claim 1 , wherein the inner diameter surface processing tool is formed. In the grindstone portion, a plurality of thin metal plates are arranged on a cylindrical contour along the outer peripheral portion of the tool main body to form a hollow grindstone main body, and abrasive grains are electrically connected to the outer peripheral surface of the grindstone main body. The inner surface machining tool according to claim 1 , wherein the inner surface machining tool is attached. As the processing tool, the inner surface machining tool according to any one of claims 1, 3, 4, and 5 is attached to the main shaft,
An inner surface processing apparatus for finishing a work hole inner diameter surface of a workpiece by the vibration imparting means, wherein a grindstone processing portion of the processing tool is subjected to widening vibration in a radial direction,
The vibration applying means comprises an ultrasonic vibrator integrally connected to a base end of the tool body, and the ultrasonic vibrator is disposed in the main shaft,
By controlling the operation of the ultrasonic vibrator during processing, it has a configuration for adjusting the amplitude amount of the widening vibration of the grindstone processing part in-process,
An inner diameter surface machining apparatus, wherein the amount of amplitude of the widening vibration of the grinding wheel machining section adjusted by the in-process is a grinding wheel wear amount. As the processing tool, the inner surface machining tool according to any one of claims 1, 3, 4, and 5 is attached to the main shaft,
An inner surface processing apparatus for finishing a work hole inner diameter surface of a workpiece by the vibration imparting means, wherein a grindstone processing portion of the processing tool is subjected to widening vibration in a radial direction,
The vibration applying means comprises an ultrasonic vibrator integrally connected to a base end of the tool body, and the ultrasonic vibrator is disposed in the main shaft,
By controlling the operation of the ultrasonic vibrator during processing, it has a configuration for adjusting the amplitude amount of the widening vibration of the grindstone processing part in-process,
Inner surface machining apparatus, wherein the amplitude of the widening oscillation of the grinding wheel working portion which is adjusted by the in-process is the amplitude amount for feature size adjustment. The inner diameter surface processing apparatus according to claim 6 or 7 , wherein power supply to the ultrasonic transducer is non-contact power feeding. The main shaft that is a rotation main shaft that is reciprocally movable in the axial direction of the inner surface of the work hole of the workpiece and is rotatably supported around the axis;
A spindle rotating means for rotating the rotating spindle around the axis, and
Main shaft reciprocating means for reciprocating the rotating main shaft in the axial direction of the inner surface of the hole to be processed;
The inner surface processing apparatus according to any one of claims 6 to 8 , further comprising control means for automatically controlling operations of the spindle rotating means and the spindle reciprocating means in conjunction with each other.

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