JP2008229799A - Electrolytic dressing grinding method and electrolysis dressing grinding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic dressing grinding method which enables grinding by using a weak conductive or non-conductive grinding fluid, and is superior in working efficiency. <P>SOLUTION: According to the method, while the weak conductive or non-conductive grinding fluid is supplied in a machining section I, a workpiece material W is continuously ground by a grindstone 20 mounted on a honing tool main body 11 in a machining cycle in which a machining period for grinding the workpiece material W and a non-machining period are alternately repeated. In this case, while the conductive fluid is supplied to an electrolytic dressing section II during the non-machining period, voltage is applied to an electrolytic dressing electrode 38 and the grindstone 20 to carry out the electrolytic dressing of the grindstone 20. Thus maintenance of a dressing state of the grindstone 20 and prevention of excessive abrasion of the same are achieved, and shortening of a machining time, grinding with stabilized quality, and extension of the life of the grindstone are attained in the machining using the weak conductive or non-conductive grinding fluid by means of the grindstone 20. Further the electrolytic dressing is performed in a very short time during the non-machining period, and therefore it is efficiently carried out without influencing the machining cycle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrolytic dressing grinding method and an electrolytic dressing grinding apparatus.

  Conventionally, honing by a honing device has been applied to finish processing of a cylindrical inner peripheral surface of a work material that requires high accuracy, such as a cylinder bore of an automobile engine. Honing is a processing method that efficiently improves processing accuracy such as roundness, straightness, and surface roughness of a cylindrical inner peripheral surface processed by precision boring, grinding, or the like.

  The honing device has, for example, a honing tool in which square rod-shaped honing grinds are radially arranged. The honing tool applies a radially outward contact pressure to the honing grindstone in contact with the cylindrical inner surface of the work material, and rotates the honing tool. However, the cylindrical inner peripheral surface is ground by giving a reciprocating motion over the entire length of the work material in the direction of the rotation axis.

  According to the honing process by the honing apparatus, a grinding trace having a special mesh pattern called a cross hatch is formed by a honing grindstone that reciprocates simultaneously with rotation. This cross hatch has a function of retaining lubricating oil required for the cylinder bore of the engine.

  In general, a honing grindstone is a square bar shape in which extremely hard and small abrasive grains such as aluminum oxide, silicon carbide, diamond and the like are bound by a binder, and the grindstone itself is dressed simultaneously by grinding the work material. A grindstone with excellent self-generation (a phenomenon in which worn abrasive grains fall off and new abrasive grains protrude) is selected.

  However, since the dressing of the honing wheel depends on the self-generated action of the grinding wheel itself, the processing accuracy of the work material in the previous process by precision boring, grinding, etc., the variation in the shape etc. due to the manufacturing of the grinding wheel itself, honing The cycle of the self-generated action of the honing grindstone varies due to the contamination of the grinding fluid used for processing.

  If there is variation in the self-acting cycle of this honing wheel, clogging with chips and drop-off crushed grains in the honing wheel gap during honing processing, clogging that does not crush even if abrasive grains wear, Concerns may arise, such as excessive grinding resistance and impact, which may cause spillage of abrasive grains, leading to deterioration of the machined surface roughness, grinding burn of the machined surface, grinding cracks, etc., and excessive machining time. Is done. For this reason, it is necessary to dress the honing grindstone frequently.

  On the other hand, in recent years, a metal bond grindstone in which abrasive grains are bonded to a honing grindstone with a conductive bonding portion of bronze or cast iron is often used. Various electrolytic dressings have been proposed as dressing methods for this type of honing grindstone.

  For example, in the electrolytic dressing method of Patent Document 1, as shown in FIG. 14, a grindstone holder 102 for electrolytic dress is attached to the main shaft of the honing head 101, and a honing grindstone 105 composed of abrasive grains and a conductive coupling portion is attached to the grindstone holder 102. On the other hand, an electrode 103 having an arcuate facing surface 103a facing a predetermined interval is disposed on the outer peripheral surface serving as a processing surface of the honing grindstone 105 positioned and fixed to the grindstone holder 102, and is passed through the flow path 113b. A voltage applying means 104 such as a power supply device for supplying a predetermined voltage between the honing grindstone 105 and the electrode 103 is provided while supplying a conductive grinding liquid such as aqueous coolant to the facing surface 103 a. Then, a predetermined voltage is applied between the honing grindstone 105 and the electrode 103, and at the same time, a conductive grinding liquid such as an aqueous coolant is supplied between the honing grindstone 105 and the electrode 103, thereby conducting the electrical conductivity of the outer surface of the honing grindstone 105. Electrolytic (electrolysis) the sexually bonded portion to cause abrasive grains to protrude.

  Further, in the electrolytic dressing of Patent Document 2, as shown in FIG. 15, a work material 112 is attached to a rotating chuck 111 of a turning center processing machine, and a metal bond grindstone 115 is attached to a chuck (not shown) that can be driven to reciprocate. An electrode 114 having an electrode surface 114 a facing the grindstone 115 and a grinding fluid supply hole 114 b is provided, and the grindstone 115 and the electrode 114 are moved back and forth between the work material 112 and the electrode 114. A predetermined voltage is applied between them, and at the same time, a conductive grinding liquid such as aqueous coolant is supplied from the grinding liquid supply hole 114b between the grindstone 115 and the electrode 114 to perform electrolytic dressing and grinding alternately.

JP 2001-62721 A Japanese Patent No. 2838314

  In the above-mentioned patent document 1, when dressing the honing grindstone 105, the grindstone holder 102 for electrolytic dress is attached to the main shaft of the honing head 101, and the honing grindstone 105 is attached to the grindstone holder 102 for electrolytic dressing. A grindstone holder 102 for electrolytic dressing is attached to the main shaft instead of the honing tool, and the honing grindstone 105 removed from the honing tool is attached to the grindstone holder 102. After dressing, the honing grindstone 105 is attached to the honing tool again and honing is performed. Since the troublesome work of removing the grindstone holder 102 from the spindle of the head 101 and attaching the honing tool is required, a lot of man-hours are required for dressing the honing grindstone 105. Affects the honing cycle, there is a concern that lowering the honing work efficiency.

  Furthermore, according to Patent Document 2, a predetermined voltage is applied between the grindstone 115 and the electrode 114 while rotating the grindstone 115 to reciprocate between the work material 112 and the electrode 114, and at the same time, the grindstone 115 and the electrode 114 is supplied with a conductive grinding fluid such as aqueous coolant and alternately performs electrolytic dressing and cutting, so that it can be used for finishing grinding using weak or non-conductive grinding fluid such as oil-based coolant. In that case, since only a weak current flows in the grinding fluid during the electrolytic dressing, the electrolytic dressing ability for the grindstone 115 is remarkably reduced or the electrolytic dressing becomes impossible due to an unstable electrolytic current or a current that does not flow. There is concern about becoming.

  Accordingly, an object of the present invention made in view of such a point is to provide an electrolytic dressing grinding method and an electrolytic dressing grinding apparatus capable of grinding by using a weakly conductive or nonconductive grinding liquid and having excellent work efficiency. is there.

  The invention of the electrolytic dressing grinding method according to claim 1, which achieves the above object, comprises mounting a grindstone comprising abrasive grains and a conductive joint for fixing the abrasive grains on a tool, and performing weak or non-conductive grinding. It has a grinding cycle in which the work material is ground sequentially and continuously by grinding the work material with the grindstone while supplying the liquid, and the work material is electrolyzed with the grindstone at the non-work time. The electrode for dressing is made to face with an interval for the presence of the conductive liquid, and a voltage is applied to the grindstone and the electrode for electrolytic dressing while supplying the conductive liquid between the wheel and the electrode for electrolytic dressing. Electrolytic dressing.

  According to this invention, while supplying weakly conductive or nonconductive grinding fluid such as oil-based coolant, grinding the work material continuously by repeating the processing time and non-processing time of grinding with a tool equipped with a grindstone, Since the grindstone is electrolytically dressed by applying a voltage to the grindstone and the electrode for electrolytic dressing while supplying the conductive liquid such as aqueous coolant with the grindstone facing the electrode for electrolytic dressing in the non-processing time, Electrolytic dressing can be performed even when grinding with the use of non-conductive grinding fluid, making it possible to maintain the sharpness of the grinding wheel and to suppress excessive wear of the grinding wheel. In processing using liquid, processing time can be shortened and tool life can be extended, and stable quality grinding can be performed. Moreover, the electrolytic dressing can be performed in a very short time in the non-working time, and can be executed efficiently without affecting the working cycle, and the work efficiency is excellent.

  The invention of the electrolytic dressing grinding method according to claim 2, which achieves the above object, comprises a tool equipped with a grindstone comprising abrasive grains and a conductive joint for fixing the abrasive grains, and a work holding a work material. A voltage is applied to the processing part having a material holding part and a grinding liquid supply means for supplying a weakly conductive or nonconductive grinding liquid, and the grindstone and the electrode for electrolytic dressing that are opposed to each other with an interval in which the conductive liquid is present. And an electrolytic dressing section provided with a conductive liquid supply means, and is held on the work material holding section with the grindstone while supplying weakly conductive or nonconductive grinding liquid at the processing section. A grinding cycle for grinding the work material successively and successively by repeating the processing time and non-working time for grinding the work material, and for the grinding stone and the electrolytic dressing in the electrolytic dressing section at the non-working time. Conductive with electrode Electrolyze the grindstone by applying a voltage to the grindstone and the electrode for electrolytic dressing while supplying the conductive liquid from the conductive liquid supply means between the grindstone and the electrode for electrolytic dressing. It is characterized by dressing.

  According to the present invention, the processing time and the non-processing time for grinding the work material held in the work material holding part by the grindstone mounted on the tool while supplying the weakly conductive or non-conductive grinding liquid in the work part. In the electrolytic dressing section during non-processing time, the voltage application means is applied to the opposing electrode for electrolytic dressing and the grindstone while supplying the conductive liquid from the conductive liquid supply means. Therefore, even if grinding is performed using a weakly conductive or non-conductive grinding liquid, electrolytic dressing can be performed, and the sharpening state of the grindstone can be maintained and the grindstone can be maintained. Excessive wear can be suppressed, and in machining using weakly conductive or non-conductive grinding fluid, machining time can be shortened and tool life can be extended, and stable quality grinding can be achieved. . Further, the electrolytic dressing can be performed in a very short time in the non-processing time, and can be executed efficiently without affecting the processing cycle.

  The invention according to claim 3 is the electrolytic dressing grinding method according to claim 1 or 2, wherein the conductive liquid is an aqueous coolant or an aqueous cleaning liquid.

  The present invention shows a specific example of the conductive liquid, and can be easily realized by using an aqueous coolant as the conductive liquid, has excellent versatility, and does not adversely affect the tool. . Alternatively, by using an aqueous cleaning liquid as the conductive liquid, the weakly conductive or non-conductive grinding liquid adhering to the grindstone during electrolytic dressing is surely washed away, and the conductive state between the grindstone and the electrode for electrolytic dressing is changed. It is good and can perform electrolytic dressing effectively.

  The invention of the electrolytic dressing grinding apparatus according to claim 4, which achieves the above object, comprises a tool equipped with a grindstone composed of abrasive grains and a conductive joint for fixing the abrasive grains, and a work holding a work material. A workpiece holding portion and a grinding fluid supply means for supplying a weakly conductive or nonconductive grinding fluid, and the work material held by the workpiece holding portion while supplying the weakly conductive or nonconductive grinding fluid is A processing part that continuously grinds the work material by successively repeating a processing time and a non-processing time for grinding with a grindstone, an electrode for electrolytic dressing arranged in a tool storage part, and an electrode for the electrode dressing A voltage applying means for applying a voltage to the grindstone disposed oppositely, and an electrolytic dressing section having a conductive liquid supplying means for supplying a conductive liquid between the electrode for electrolytic dressing and the grindstone, and in the non-working time Electrolytic dressing The tool is inserted into the tool housing portion at the wrapping portion, the grindstone and the electrode for electrolytic dressing are opposed to each other with an interval for allowing the conductive liquid to exist, and the conductive material is interposed between the grindstone and the electrode for electrolytic dressing. While supplying a conductive liquid from the liquid supply means, a voltage is applied to the grindstone and the electrode for electrolytic dressing to electrolytically dress the grindstone.

  According to this invention, the work material held in the work material holding part by the grindstone mounted on the tool while supplying weakly conductive or non-conductive grinding liquid such as oil-based coolant by the grinding liquid supply means in the machining part is provided. For electrolytic dressing while grinding the work material continuously by repeating the grinding time and non-working time, and supplying the conductive liquid such as aqueous coolant from the conductive liquid supply means in the electrolytic dressing part during the non-working time Since the electrode and the grinding stone are subjected to electrolytic dressing by applying a voltage to the grinding wheel, electrolytic dressing can be performed even when grinding is performed using a weakly conductive or non-conductive grinding fluid. Maintenance and suppression of excessive wear of the grindstone are possible, and excessive reduction of the grinding ability by the grindstone is suppressed. As a result, in processing using weakly conductive or nonconductive grinding fluid in the processing portion, the processing time can be shortened and the tool life can be extended, and stable quality grinding can be performed. Electrolytic dressing can be performed in an extremely short time because the electrolytic dressing is applied to the electrode for electrolytic dressing and the grinding wheel while supplying the conductive liquid from the conductive liquid supply means in the non-working time, and the machining cycle can be performed in a very short time. It can be executed efficiently without affecting the work efficiency.

  According to a fifth aspect of the present invention, in the electrolytic dressing grinding apparatus according to the fourth aspect of the present invention, the electrolytic dressing grinding apparatus has a processing time measuring means for measuring the processing time, and when the processing time reaches a preset threshold value, the electrolytic dressing It is characterized by doing.

  The present invention has been made by paying attention to the fact that when the abrasive grains are worn by grinding, the grinding ability gradually decreases and the processing time gradually increases. When the processing time reaches a preset threshold, Electrolytic dressing can effectively perform electrolytic dressing at an appropriate time, and processing using weakly conductive or nonconductive grinding fluid in the processing part without excessively reducing the grinding ability of the grindstone Therefore, it is possible to shorten the machining time and to perform stable quality grinding. Moreover, since excessive wear of the grindstone is suppressed by the electrolytic dressing, the processing time can be shortened and the processing cycle can be made more efficient.

  According to a sixth aspect of the invention, in the electrolytic dressing grinding apparatus of the fourth aspect, the electrolytic dressing is performed every preset non-working time.

  According to the present invention, by performing electrolytic dressing every preset non-working time, it is possible to effectively perform electrolytic dressing for each accurate cycle, without excessively reducing the grinding ability of the grindstone, and processing parts Therefore, in processing using a weakly conductive or non-conductive grinding fluid, it is possible to shorten the processing time and perform stable quality grinding. Moreover, since excessive wear of the grindstone is suppressed by the electrolytic dressing, the processing time can be shortened and the processing cycle can be made more efficient.

  A seventh aspect of the present invention is the electrolytic dressing grinding apparatus according to any one of the fourth to sixth aspects, wherein the tool is supported by a main shaft and driven to rotate, and an outer periphery of the honing tool main body. A honing tool including the rod-shaped grindstones arranged radially, wherein the electrode for electrolytic dressing allows the insertion of the honing tool main body and the grindstone that are supported by the main shaft and descend from above, and each grindstone The electrode surfaces are arranged opposite to each other at a distance from each other and are arranged in the tool accommodating portion.

  The present invention is limited to a honing tool including a honing tool main body provided on a main shaft and a rod-shaped grindstone arranged radially on the outer periphery of the honing tool main body, and the electrode for electrolytic dressing of the electrolytic dressing section has a specific shape The electrode for electrolytic dressing allows the insertion of a honing tool body and a grindstone that are supported by the main shaft from the upper side and descends, and the electrode surface is opposed to each grindstone with a gap therebetween. Arranged in the accommodating part.

  The invention according to claim 8 is the electrolytic dressing grinding apparatus according to claim 7, wherein the electrode for electrolytic dressing allows insertion of a honing tool main body and a grindstone that are supported by the main shaft and descend from above, and each grindstone It is characterized by the cylindrical shape with which an electrode surface opposes at intervals.

  According to a ninth aspect of the present invention, in the electrolytic dressing grinding apparatus according to the seventh aspect, the electrode for electrolytic dressing allows insertion of a honing tool body and a grindstone that are supported by the main shaft and descend from above, and each grindstone A plurality of the electrode surfaces are arranged radially in the tool accommodating portion with a gap therebetween.

  The electrode dressing electrode of the electrolytic dressing portion is limited to a specific cylindrical shape according to the honing tool, and the electrode dressing electrode is radially arranged with the electrode surfaces facing each other. It is limited to a specific shape that is arranged in a plurality in the accommodating portion.

    The invention according to claim 10 is the electrolytic dressing grinding apparatus according to any one of claims 4 to 9, wherein the conductive liquid is an aqueous coolant or an aqueous cleaning liquid.

  This invention shows a specific example of the conductive liquid. By using an aqueous coolant as the conductive liquid, it can be easily dealt with and is excellent in versatility and realized without adversely affecting the honing tool. it can. Alternatively, by using an aqueous cleaning liquid as the conductive liquid, the weakly conductive or non-conductive grinding liquid adhering to the grindstone during electrolytic dressing is surely washed away, and the conductive state between the grindstone and the electrode for electrolytic dressing is changed. It is good and can perform electrolytic dressing effectively.

  According to the present invention, while a weakly conductive or non-conductive grinding fluid is supplied, a workpiece is ground continuously by repeating a processing time and a non-processing time for grinding with a tool equipped with a grindstone, while in a non-processing time By applying a voltage to the grindstone and the electrode for electrolytic dressing while supplying the conductive liquid between the grindstone and the electrode for electrolytic dressing, electrolytic grinding is performed on the grindstone to perform grinding by using a weakly conductive or non-conductive grinding liquid. Even in this case, electrolytic dressing is possible, shortening the processing time and maintaining stable quality in processing using weakly conductive or non-conductive grinding fluid that maintains the sharpness of the grinding wheel and suppresses excessive wear. Can be ground. Moreover, the electrolytic dressing can be performed in a very short time in the non-working time, and can be executed efficiently without affecting the working cycle, and the work efficiency is excellent.

  Hereinafter, embodiments of the electrolytic dressing grinding method and the electrolytic dressing grinding apparatus of the present invention will be described with reference to FIGS. 1 to 7 by taking a honing method and a honing apparatus as an example.

  FIG. 1 is a schematic explanatory diagram of a honing device, FIG. 2 is a configuration diagram of a honing tool 10 that is a tool, and FIG. 3 is a view taken in the direction of arrow A in FIG. The honing tool 10 is swingably supported by a main shaft 1 of a honing head that includes a driving device such as a main shaft motor, and is configured to be rotatable about the rotation axis Z by the main shaft 1. The main shaft 1 and the honing tool 10 are provided with a machining portion I for grinding, that is, honing, a workpiece W having a cylindrical inner peripheral surface Wa to be honed, such as an engine cylinder bore shown in FIG. It moves between the dressing part II.

  As shown in FIGS. 2 and 3, the honing tool 10 includes a hollow cylindrical honing tool main body 11 whose upper end is supported by the main shaft 1. A plurality of, in the present embodiment, twelve honing shoe guide holes 12 extending along the extending direction of the rotary shaft Z are opened at equal intervals on the outer periphery of the honing tool main body 11, and are slid into the honing shoe guide holes 12. The first honing shoe 13A and the second hosing shoe 13B are alternately fitted and mounted so as to be movable in a radial direction that is guided by movement and moves toward and away from the rotation axis Z.

  In the first honing shoe 13A and the second honing shoe 13B, a grindstone mounting groove 13a extending along the rotation axis Z direction is formed on the outer end surface, and both side surfaces 13b are slidable on the end surface 12a of the honing shoe guide hole 12. The engaging grooves 13c and 13d are formed at both ends of the outer peripheral surface, respectively.

  A proximal-side tapered surface 13Aa and a distal-side tapered surface 13Ab that gradually approach the rotational axis Z are formed in the proximal-side range and the distal-side range of the inner end surface of the first honing shoe 13A as they move from the proximal side to the distal side. Has been. A proximal-side tapered surface 13Ba and a distal-side tapered surface 13Bb that gradually approach the rotation axis Z as the transition from the proximal end side to the distal end side occurs in the proximal end range and the distal end range of the inner end surface of the second honing shoe 13B, respectively. Has been. The engaging grooves 13c and 13d of the first honing shoe 13A and the second honing shoe 13B are fitted with annular spring bands 14a and 14b serving as a diameter urging means, and the spring bands 14a and 14b respectively The first honing shoe 13A and the second honing shoe 13B are urged in the direction of the rotation axis Z, that is, in the radially inwardly decreasing direction.

  A rod-shaped grindstone extending along the rotation axis Z direction, that is, a honing grindstone 20 is attached to each grindstone mounting groove 13a of the first honing shoe 13A and the second homing shoe 13B. The honing grindstone 20 is composed of, for example, a metal bond grindstone in which abrasive grains such as diamond, CBN (cubic boron nitride), crystalline aluminum oxide, silicon carbide, and the like are bonded by a conductive bonding portion made of bronze or cast iron. Yes.

  Further, a plurality of honing guide member mounting grooves 11a extending along the rotation axis Z direction at equal intervals are formed on the outer periphery of the honing tool main body 11, and the honing guide member mounting grooves 11a are made of ceramic or the like via the mounting member 15. A honing guide member 16 extending in the direction of the rotation axis Z is attached. The distance from the rotation axis Z to the outer peripheral surface 16a of each honing guide member 16 is formed constant. Further, an air passage 11b for an air micrometer (not shown) for accurately measuring the gap between the outer peripheral surface 16a of the honing guide member 16 and the processing surface by air pressure is formed in the honing tool main body 11, and the outer peripheral surface 16a of the honing guide member 16 is formed. Is open.

  The proximal end side penetrating through the honing tool main body 11 and slidably comes into contact with the proximal tapered surface 13Aa and the distal tapered surface 13Ab of the first honing shoe 13A and gradually approaches the rotation axis Z as it moves to the distal end side. A first expansion / contraction bar 17 </ b> A having a tapered surface 17 </ b> Aa and a tip-side tapered surface 17 </ b> Ab is disposed in the honing tool main body 11. Further, a base which is coupled to the first expansion / contraction bar 17A and slidably contacts the proximal side taper surface 13Ba and the distal side taper surface 13Bb of the second honing shoe 13B and gradually approaches the rotation axis Z as it moves to the distal end side. A second expansion / contraction bar 17B in which the end tapered surface 17Ba and the tip tapered surface 17Bb are formed is disposed in the honing tool main body 11.

  The first expansion / contraction bar 17A and the second expansion / contraction bar 17B are pulled and released by a traction operation mechanism (not shown) disposed in the honing head. Further, the first expansion / contraction bar 17A and the second expansion / contraction bar 17B are constantly urged toward the distal end side by a spring 18 disposed in the honing tool main body 11.

  By releasing the traction by the traction operation mechanism of the honing head, the proximal end side taper surface 17Aa and the front end side taper surface 17Ab of the first expansion / contraction bar 17A are urged by the spring 18 and the proximal end side taper surface 13Aa of the first honing shoe 13A and The first honing shoes 13A are pushed outward in the radial direction away from the rotation axis Z while being in pressure contact with the tip-side tapered surface 13Ab. Similarly, the proximal end tapered surface 17Ba and the distal end tapered surface 17Bb of the second expansion / contraction bar 17B are in pressure contact with the proximal end tapered surface 13Ba and the distal end tapered surface 13Bb of the second honing shoe 13B, respectively. 13B is pushed outward in the radial direction away from the rotation axis Z.

  On the other hand, by pulling the first expansion / contraction bar 17A and the second expansion / contraction bar 17B by the pulling operation mechanism against the urging of the spring 18, the proximal-side taper surface 17Aa and the distal-side taper surface 17Ab of the first expansion / contraction bar 17A. The second honing shoe by the proximal end taper surface 17Ba and the distal end side taper surface 17Bb of the second expansion / contraction bar 17B is released, while the pressing of the proximal end taper surface 13Aa and the distal end side taper surface 13Ab of the first honing shoe 13A is released. The pressing of the proximal end taper surface 13Ba and the distal end taper surface 13Bb of 13B is released. The first honing shoe 13A and the second honing shoe 13B released from the pressure by the first expansion / contraction bar 17A and the second expansion / contraction bar 17B are moved in the direction of the rotation axis Z, that is, in the diameter reduction direction by the spring bands 14a and 14b. . The honing tool body 11 is provided with an electrode 23 connected to the voltage applying means.

  FIG. 4 is a diagram showing an outline of a processing portion I that performs honing on the cylindrical inner peripheral surface Wa of the work material W. In the machining part I, a workpiece holding part (not shown) for positioning and holding the workpiece W, and a honing tool main body 11 which is arranged above the workpiece holding part and descends from above are held by the workpiece holding part. A cylindrical insertion guide 25 is provided for guiding and guiding into the cylindrical inner peripheral surface Wa of the work material W. Further, the cylindrical inner peripheral surface Wa of the work material W to be processed is provided with weak conductivity such as oil-based coolant. A grinding fluid supply means (not shown) for supplying a non-conductive grinding fluid is disposed. That is, in the processing section I, finish grinding using weakly conductive or nonconductive grinding fluid such as oil-based coolant is performed.

  In this processing part I, the work material W carried in is held in the work material holding part, and the first expansion / contraction bar 17A and the second expansion / contraction bar 17B of the honing tool 10 by the traction operation mechanism disposed in the honing head. The honing tool 10 in a diameter-reduced state in which the first honing shoe 13A and the second honing shoe 13B are moved in the rotation axis Z direction, that is, the diameter-reducing direction, is guided by the insertion guide 25 while the workpiece W is pulled. It inserts in the cylindrical inner peripheral surface Wa. With the honing tool main body 11 inserted into the cylindrical inner peripheral surface Wa, the honing tool 10 is reciprocated in the direction of the rotation axis Z while rotating the honing tool 10 while supplying a weakly conductive or non-conductive grinding fluid such as oil coolant. In addition, the traction of the first expansion / contraction bar 17A and the second expansion / contraction bar 17B of the honing tool 10 by the traction operation mechanism is released.

  By releasing the pulling, the first expansion / contraction bar 17A and the second expansion / contraction bar 17B are moved to the distal end side by the urging force of the spring 18, and the proximal end side tapered surface 17Aa and the distal end side tapered surface 17Ab of the first expansion / contraction bar 17A are respectively The first honing shoe 13A is pressed outwardly in the radial direction away from the rotation axis Z while being pressed against the proximal end side tapered surface 13Aa and the distal end side tapered surface 13Ab of the one honing shoe 13A. Similarly, the proximal end tapered surface 17Ba and the distal end tapered surface 17Bb of the second expansion / contraction bar 17B are in pressure contact with the proximal end tapered surface 13Ba and the distal end tapered surface 13Bb of the second honing shoe 13B, respectively. The outer surface 21 of each honing grindstone 20 comes into contact with the cylindrical inner peripheral surface Wa of the work material W by pushing 13B outward in the radial direction away from the rotation axis Z. Then, the cylindrical inner peripheral surface Wa is ground by the honing grindstone 20 with a preset contact pressure, that is, honing is started.

  A gap between the outer peripheral surface 16a of the honing guide member 16 and the cylindrical inner peripheral surface Wa of the workpiece W to be processed is detected by an air micrometer while honing is performed, and the outer peripheral surface 16a of the honing guide member 16 and the processed surface are detected. When the gap reaches a predetermined value, the first expansion / contraction bar 17A and the second expansion / contraction bar 17B are pulled by the traction operation mechanism, and the first honing is performed by the proximal end taper surface 17Aa and the distal end taper surface 17Ab of the first expansion / contraction bar 17A. The proximal end side taper surface 13Aa and the distal end side tapered surface 13Ab of the shoe 13A are released, and the proximal end side of the second honing shoe 13B by the proximal end side tapered surface 17Ba and the distal end side tapered surface 17Bb of the second expansion / contraction bar 17B. The pressing of the taper surface 13Ba and the tip side taper surface 13Bb is released. Accordingly, the first honing shoe 13A and the second honing shoe 13B are moved in the rotation axis Z direction, that is, the diameter reducing direction by the spring bands 14a and 14b, so that each honing grindstone 20 is a work surface of the work material W. The honing process ends after leaving the cylindrical inner peripheral surface Wa. The machining time is from the start of the honing process to the end of the honing process.

  When the honing process is completed, the rotation of the honing tool 10 and the reciprocation in the direction of the rotation axis Z are stopped, the honing head is raised, and the honing tool body 11 is inserted into the cylindrical inner peripheral surface Wa of the work material W from the insertion guide 25. Then, it is retracted to the upper position. Thereafter, the work material W subjected to the honing process is carried out from the work material holding part, and the work material W to be subjected to the next honing process is carried in and held in the work material holding part. That is, the work material is carried out and carried in during the non-machining time from the end of honing to the start of the next honing.

  From the process of holding the loaded work material W to the work material holding part, the process of carrying out the honing work material W from the work material holding part, that is, the grinding process in which the machining time and the non-working time are sequentially repeated. The work material W can be honed sequentially sequentially by the cycle.

  A time chart of this grinding cycle is shown in FIG. In FIG. 7, the horizontal axis represents time, and the vertical strokes indicate the lifting and lowering operations of the honing tool 10 by the honing head, and “ON” and “OFF” of the spindle motor indicate the rotation and stop of the spindle 1, that is, the honing tool 10. Corresponding to this, the operations of expanding and reducing the diameter of the honing grindstone 20 are shown, and the work material W is carried in and out during the non-machining time when the main shaft 1 is in the raised position.

  By repeating the processing time and the non-processing time in this grinding processing cycle, the grinding ability gradually decreases due to the abrasion of the abrasive grains of each honing grindstone 20, and each processing time becomes gradually longer. A processing time measuring means for measuring the processing time is provided, and when the processing time reaches a preset threshold value, that is, when the grinding ability is reduced to a set level due to wear of abrasive grains, the honing grindstone is used in the non-processing time. Electrolytic dressing 20 is used to ensure processing accuracy.

  FIG. 5 is a diagram showing an outline of the electrolytic dressing portion II for electrolytic dressing the honing grindstone 20 of the honing tool 10, and FIG. 6 is a cross-sectional view taken along the line II of FIG. 5.

  The electrolytic dressing part II is provided with a storage tank 31 for storing a conductive liquid having a bottom 32 and a peripheral wall 33 and having an open top, in this embodiment, an aqueous coolant 40, and a honing tool above the storage tank 31. A tool storage portion 35 made of an insulating material for positioning and holding 10 is provided.

  The tool accommodating portion 35 has an annular honing tool holding portion 36 for positioning the honing tool 10 with the discharge port 35a being opened at the center and the honing tool main body 11 being placed, and a lower end on the outer periphery of the honing tool holding portion 36. Are formed in a substantially cylindrical shape in which a cylindrical electrode holding portion 37 is formed so as to form an opening 35b opened at the upper end.

  The electrode holding portion 37 has a height slightly larger than the length of the honing grindstone 20, and is provided with a cylindrical electrolytic dressing electrode (hereinafter referred to as ELID electrode) 38 having an electrode surface 38a along the inner peripheral surface 37a. . The ELID electrode 38 is made of, for example, iron, and a terminal (not shown) is connected to a negative electrode (negative electrode) of a voltage applying unit (not shown).

  The electrode surface 38 a of the ELID electrode 38 disposed along the inner peripheral surface 37 a of the electrode holding portion 37 allows insertion of the honing tool body 11 and the honing grindstone 20 that are supported by the spindle 1 and descend from above. And an outer surface 21 of each honing grindstone 20 disposed on the honing tool 10 positioned and positioned on the honing tool holding portion 36, and facing each honing grindstone 20 with a space therebetween. Oppositely conductive liquid, in the present embodiment, a gap allowing the interposition of the aqueous coolant 40, for example, an inner diameter in which about 1 to 5 mm is formed, and a length in the vertical direction slightly larger than the length of the honing grindstone 20 have.

  Furthermore, the electroconductive liquid supply means 39 which ejects and supplies the aqueous | water-based coolant stored in the storage tank 31 in the tool accommodating part 35 from the opening part 35b is provided. The aqueous coolant stored in the storage tank 31 by the conductive liquid supply means 39 is supplied into the tool storage portion 35 from the upper opening 35b, and the aqueous coolant supplied into the tool storage portion 35 flows down from the discharge port 35a. Then, it is collected again in the storage tank 31.

  The honing tool 10 is moved above the tool accommodating part 35 of the electrolytic dressing part II by the movement of the main shaft 1 by the honing head or the movement of the electrolytic dressing part II from the processing part I, and the main shaft 1 is lowered along the rotation axis Z. Then, the honing tool 10 is lowered and inserted into the tool storage portion 35 and positioned and placed on the honing tool holding portion 36. In the honing tool 10 positioned and mounted on the honing tool holding portion 36, the outer surface 21 of each honing grindstone 20 faces the electrode surface 38a of the ELID electrode 38 with a gap. Further, the honing tool 10 is pulled upward from the tool accommodating portion 35 by the main shaft 1 rising, and is returned to the processing portion I by the movement of the main shaft 1 by the honing head or the movement of the electrolytic dressing portion II.

  Further, when the honing tool 10 is moved above the tool accommodating portion 35 of the electrolytic dressing portion II by the movement of the main shaft 1 by the honing head or the movement of the electrolytic dressing portion II from the processing portion I, the conductive liquid supply means is synchronized with this. When the hoisting tool 10 moves from the upper side of the tool accommodating portion 35 to the processing portion I, the conductive liquid supply means 39 is stopped accordingly. Thus, the supply of the aqueous coolant is stopped.

  Then, when the honing tool 10 is moved above the tool accommodating portion 35 of the electrolytic dressing portion II by the movement of the main shaft 1 by the honing head or the movement of the electrolytic dressing portion II from the processing portion I, the conductive liquid supply means is moved by the movement. The supply of the aqueous coolant into the tool storage unit 35 by 39 is started. The main shaft 1 of the honing head is lowered along the rotation axis Z or moved through the electrolytic dressing portion II in a state where the aqueous coolant is supplied to the tool storage portion 35. An aqueous coolant in which oil-based coolant and fine abrasive powder, grinding powder, etc. adhering to the honing tool 10 and the honing grindstone 20 are ejected from the conductive liquid supply means 39 by the lowering of the honing tool 10 or the movement of the electrolytic dressing part II. To be removed by washing.

  Further, the honing tool 10 is lowered or the electrolytic dressing part II is moved and inserted into the tool storage part 35 and positioned and placed on the honing tool holding part 36. The honing tool 10 positioned on the honing tool holding part 36 has an electrode surface 38a of the ELID electrode 38 and an outer surface 21 of each honing grindstone 20 via an aqueous coolant 40 supplied from the conductive liquid supply means 39. opposite.

  While the honing tool 10 is positioned and held on the honing tool holder 36, a negative voltage is applied to the ELID electrode 38 for a preset dressing time from the voltage applying means, and each honing grindstone 20 is positively applied by the voltage applying means. A voltage is applied, and the electroconductive dressing is electrolyzed on the outer surface 21 of each honing grindstone 20 by electrolytic action to perform electrolytic dressing. In this electrolytic dressing, since the aqueous coolant 40 interposed between the electrode surface 38a of the ELID electrode 38 and the outer surface 21 of the honing grindstone 20 is excellent in conductivity, a stable electrolytic dressing can be obtained. This electrolytic dressing time is determined by the electrolytic voltage, the amount of protrusion of the abrasive grains, the material of the conductive coupling portion, and the like, but can be set by appropriately finding an optimal arbitrary time by experiment or simulation. Moreover, the protrusion amount of the abrasive grains can be optimized by the electrolytic voltage and the electrolytic dressing time.

  After the dressing time elapses, voltage application to the ELID electrode 38 and the grindstone 20 is stopped, and when the electrolytic dressing of the honing grindstone 20 is finished, the honing tool 10 is moved to the tool housing portion 35 by the movement of the spindle 1 or the movement of the electrolytic dressing portion II. It is pulled out from the inside and returned to the processing part I by the movement of the main shaft 1 by the honing head or the movement of the electrolytic dressing part II. The time required for this electrolytic dressing is sufficiently short and does not affect the honing cycle. The timing of this electrolytic dressing is shown in FIG.

  Therefore, according to the present embodiment, the honing grindstone 20 is worn by repeating the honing with the honing tool 10 attached to the spindle 1 using weakly conductive or nonconductive grinding fluid such as oil-based coolant in the machining portion I. When the grinding ability is reduced due to, for example, the machining time exceeds a preset threshold, the honing tool 10 is moved together with the spindle 1 to the electrolytic dressing part II, or the electrolytic dressing part II is moved to conduct the electrolytic dressing. Electrolytic dressing is possible even when grinding by using weakly conductive or non-conductive grinding fluid such as oil-based coolant by applying electrolytic dressing to the honing grindstone 20 using an aqueous coolant that is excellent in performance. As a result, it is possible to perform honing with stable quality without variation in surface roughness. In addition, excessive wear of the honing grindstone 20 is suppressed, and work efficiency is improved as the machining time is shortened.

  The electrolytic dressing in the electrolytic dressing section II can be set to a non-machining time such as loading and unloading of the work material W in a state where the honing tool 10 is attached to the main shaft 1 and in a very short time. This can be realized without affecting the machining cycle.

  Furthermore, by using an aqueous coolant as the conductive liquid, it can be easily dealt with, has excellent versatility, and can be realized without adversely affecting the honing tool.

  In the above embodiment, the cylindrical ELID electrode 38 is provided in the honing tool accommodating portion 35 disposed in the electrolytic dressing portion II. However, instead of the cylindrical ELID electrode 38, various shapes of ELID electrodes are used. It is possible to provide.

  For example, FIG. 8 shows a cross-sectional view of the tool storage portion 35 corresponding to FIG. 5, and FIG. 9 shows a cross-sectional view taken along line II-II of FIG. A plurality of electrode surfaces 38Aa of the ELID electrode 38A formed in a flat plate shape having a rectangular cross section continuous in the vertical direction along the peripheral surface 37a are exposed from the inner peripheral surface 37a and radially arranged at equal intervals in the circumferential direction. It is also possible to do. The ELID electrode 38A can be manufactured very easily by cutting a flat conductive material. Further, since a plurality of the electrodes are arranged at equal intervals, it can be obtained from a small amount of material as compared with the cylindrical ELID electrode 38.

  10 shows a sectional view of the tool storage portion 35 corresponding to FIG. 5, and FIG. 11 shows a sectional view taken along the line III-III of FIG. It is also possible to dispose a plurality of electrode surfaces 38Ba of the ELID electrode 38B that are formed in an arc cross-sectional shape continuous in the vertical direction along the peripheral surface 37a so as to be exposed from the inner peripheral surface 37a at equal intervals in the peripheral direction. It is. The ELID electrode 38B can be manufactured very easily by cutting a continuous conductive material having a circular arc cross section.

  Further, FIG. 12 shows a sectional view of the tool accommodating portion 35 corresponding to FIG. 5, and FIG. 13 shows a sectional view taken along line IV-IV in FIG. 12, and the cylindrical end face is an electrode surface 38Ca of the ELID electrode 38C. It is also possible to expose a plurality of radial positions from the inner peripheral surface 37a of the electrode holding portion 37 at equal intervals in the circumferential direction. The ELID electrode 38C can be manufactured very easily by cutting a columnar conductive material. In addition, since a plurality of cylindrical ELID electrodes 38C are arranged in the circumferential direction at equal intervals, it can be obtained from a very small amount of conductive material.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the processing time required for the honing process is measured and the timing of the electrolytic dressing of the honing grindstone 20 is set. However, focusing on the fact that the grinding resistance gradually increases as the honing grindstone 20 wears, Set the timing of the electrolytic dressing so that the electrolytic dressing is performed when the resistance exceeds a preset threshold value, or set the electrolytic dressing timing so that the electrolytic dressing is performed every preset non-processing time You can also

  By performing electrolytic dressing every preset non-working time, the grinding ability of the grinding wheel is not excessively reduced, and stable in machining with a honing grindstone using weakly conductive or non-conductive grinding fluid in the machined part Quality grinding is possible. Further, the electrolytic dressing can maintain the sharpened state of the honing grindstone and suppress excessive wear, so that the machining time can be shortened and the machining cycle can be made more efficient and the grindstone life can be extended.

  In the above embodiment, honing is described as an example. However, the present invention is not limited to honing, and of course, the honing is not limited to honing. Electrolytic dressing grinding method in other grinding processes such as super-finishing using a grinding stone composed of abrasive grains and a conductive coupling part for fixing the abrasive grains, using a weakly conductive or non-conductive grinding liquid at the time of grinding It can also be applied to an electrolytic dressing grinding apparatus.

  Furthermore, in the said embodiment, although conductive grinding liquids, such as aqueous coolant, were used as a conductive liquid, not only this but an appropriate conductive liquid can be used. For example, by using an aqueous cleaning liquid as the conductive liquid, the weakly conductive or non-conductive grinding liquid adhered to the grindstone during electrolytic dressing can be surely washed away, and the conductive state between the grindstone and the electrode for electrolytic dressing The electrolytic dressing can be effectively performed.

It is an outline explanatory view of a honing device concerning an embodiment of the invention. It is a block diagram of a honing tool. FIG. 3 is a view taken in the direction of arrow A in FIG. 2. It is a figure which shows the outline | summary of a process part. It is a figure which shows the outline | summary of an electrolytic dressing part. It is the II sectional view taken on the line of FIG. It is a time chart of a grinding cycle. It is sectional drawing of the tool accommodating part by which the electrode for electrolytic dressing of rectangular cross-sectional shape was arrange | positioned. It is the II-II sectional view taken on the line of FIG. It is sectional drawing of the tool accommodating part by which the electrode for electrolytic dressing of circular cross-sectional shape was arrange | positioned. It is the III-III sectional view taken on the line of FIG. It is sectional drawing of the tool accommodating part by which the electrode for columnar electrolytic dressing was arrange | positioned. It is the IV-IV sectional view taken on the line of FIG. It is a schematic diagram of the electrolytic dressing means of the conventional honing grindstone. It is a schematic diagram of the electrolytic dressing means of the conventional honing grindstone.

Explanation of symbols

I Processing part II Electrolytic dressing part 1 Spindle 10 Honing tool (tool)
11 Honing tool body 12 Honing shoe guide holes 13A, 13B First honing shoe, second honing shoe (honing shoe)
15 mounting members 17A, 17B first expansion / contraction bar, second expansion / contraction bar (expansion / contraction bar)
20 Honing wheel
DESCRIPTION OF SYMBOLS 21 Outer surface 31 Storage tank 32 Bottom part 33 Perimeter wall 35 Tool accommodating part 35a Discharge port 35b Opening part 36 Honing tool holding part 37 Electrode holding part 37a Inner peripheral surface 38 Electrode for electrode dressing (ELID electrode)
38a Electrode surface 38A Electrode dressing electrode (ELID electrode)
38Aa Electrode surface 38B Electrode dressing electrode (ELID electrode)
38Ba Electrode surface 38C Electrode dressing electrode (ELID electrode)
38Ca electrode surface 39 conductive liquid supply means 40 aqueous coolant (conductive liquid)
W Work material Wa Cylindrical inner peripheral surface

Claims (10)

A grinding wheel composed of an abrasive grain and a conductive joint for fixing the abrasive grain is mounted on a tool, and the processing time and non-machining of grinding the work material with the grinding stone while supplying a weakly conductive or non-conductive grinding fluid. It has a grinding cycle that grinds the work material sequentially and sequentially over time,
For the non-working time, the grinding wheel and the electrode for electrolytic dressing are opposed to each other with an interval for allowing the conductive liquid to exist, and the conductive liquid is supplied between the grinding stone and the electrode for electrolytic dressing while the electrode for electrolytic dressing is used. An electrolytic dressing grinding method, wherein voltage is applied to an electrode to electrolytically dress a grindstone. A tool equipped with a grindstone composed of abrasive grains and a conductive joint for fixing the abrasive grains;
A workpiece holding section for holding a workpiece and a processing section provided with a grinding fluid supply means for supplying a weakly conductive or non-conductive grinding fluid;
An electrolytic dressing unit including a voltage applying means for applying a voltage to the grinding stone and the electrode for electrolytic dressing opposed to each other with an interval in which the conductive liquid is present and an electrode for electrolytic dressing; and
While supplying the weakly conductive or nonconductive grinding fluid at the processing section, the processing time for grinding the work material held by the work material holding section with the grindstone and the non-processing time are repeated successively and sequentially. Has a grinding cycle to grind the work material,
In the non-working time, the grinding stone and the electrode for electrolytic dressing are opposed to each other at an interval in which the conductive liquid is present in the electrolytic dressing section, and the conductive liquid supply means conducts electricity between the grinding stone and the electrode for electrolytic dressing. An electrolytic dressing grinding method characterized by applying a voltage to a grindstone and an electrode for electrolytic dressing while electrolytically dressing the grindstone while electrolytically dressing the grindstone.   3. The electrolytic dressing grinding method according to claim 1, wherein the conductive liquid is an aqueous coolant or an aqueous cleaning liquid. A tool equipped with a grindstone composed of abrasive grains and a conductive joint for fixing the abrasive grains;
A work material holding portion for holding a work material and a grinding fluid supply means for supplying a weak conductive or non-conductive grinding fluid are provided, and the work material holding portion is supplied while supplying a weak conductive or non-conductive grinding fluid. A processing unit that continuously grinds the work material successively by repeating a processing time and a non-working time for grinding the held work material with the grindstone, and
A conductive liquid is applied between the electrode for electrolytic dressing disposed in the tool housing portion, a voltage applying means for applying a voltage to the grindstone disposed opposite to the electrode for electrolytic dressing, and the electrode for electrolytic dressing and the grindstone. An electrolysis dressing unit provided with a conductive liquid supply means for supplying,
In the non-working time, the tool is inserted into the tool storage portion at the electrolytic dressing portion, and the grindstone and the electrode for electrolytic dressing are opposed to each other with an interval for the presence of a conductive liquid. An electrolytic dressing grinding apparatus characterized in that the dressing is electrolytically dressed by applying a voltage to the grindstone and the electrode for electrolytic dressing while supplying the conductive liquid from the conductive liquid supply means.   5. The electrolytic dressing grinding apparatus according to claim 4, further comprising a machining time measuring means for measuring the machining time, wherein the electrolytic dressing is performed when the machining time reaches a preset threshold value.   The electrolytic dressing grinding apparatus according to claim 4, wherein the electrolytic dressing is performed every preset non-processing time. The above tools are
A honing tool comprising a honing tool main body supported by a main shaft and driven to rotate, and the rod-shaped grindstones arranged radially on the outer periphery of the honing tool main body,
The electrode for electrolytic dressing is
5. The honing tool main body and the grindstone that are supported by the main shaft and descend from the upper side are allowed to be inserted, and the electrode surfaces are arranged in the tool accommodating portion so as to face each grindstone with a space therebetween. The electrolytic dressing grinding apparatus of any one of -6. The electrode for electrolytic dressing is
8. The electrolysis according to claim 7, wherein the honing tool main body and the grindstone supported by the spindle from above are lowered, and the electrode surface is opposed to each grindstone with a space therebetween. Dressing grinding device. The electrode for electrolytic dressing is
The honing tool main body and the grindstone that are supported by the spindle from the lower side are allowed to be inserted, and a plurality of electrode surfaces are arranged radially in the tool accommodating portion so as to face each grindstone with a space therebetween. The electrolytic dressing grinding apparatus according to claim 7.   The electrolytic dressing grinding apparatus according to any one of claims 4 to 9, wherein the conductive liquid is an aqueous coolant or an aqueous cleaning liquid.

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