JP2012183599A - Electrolytic dressing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve grinding precision by preventing a surface of a grindstone from being damaged by electrolytic dressing.SOLUTION: An electrode member 32 is provided close to a turning grindstone 20. An arcuate electrode surface 32a facing a grinding surface 20a of the turning grindstone 20 is provided on the electrode member 32. A block member 51 is put on one end of the electrode surface 32a while a block member 52 is put on the other end of the electrode surface 32a. In addition, a coolant passage 53 is formed at the electrode member 32, and the coolant passage 53 is opened at the electrode surface 32a between the block members 51 and 52. Thus, an interval between the electrode surface 32a and the grinding surface 20a can be kept constant, and in turn, so that it is possible to inhibit a variation in a coolant amount interposed between the electrode surface 32a and the grinding surface 20a. Therefore, the grinding surface 20a can be uniformly dressed, and thus the grinding precision of a workpiece can be improved while preventing the grinding surface 20a from being damaged.

Description

  The present invention relates to an electrolytic dressing apparatus that performs electrolytic dressing on a grinding surface of a disc-shaped grindstone.

  Camshaft journals and cam profiles are ground using a grinder equipped with a disk-shaped grindstone. By the way, when clogging or spillage occurs on the grindstone of the grinding machine, it is not possible to properly grind the journal, cam profile, etc., and the processing accuracy of the camshaft is lowered. In order to maintain the machining accuracy of the camshaft, it is necessary to sharpen the grindstone regularly using a tool or the like, but periodically performing such dressing work is a factor that increases the work cost. It was. Therefore, an electrolytic dressing apparatus has been proposed in which a metal bond grindstone is employed for the grinder and an electrode close to the metal bond grindstone is provided (see, for example, Patent Document 1). According to this electrolytic dressing apparatus, by performing electrolysis on the metal bond grindstone, the bonding material on the grindstone surface can be removed and dressed, and dressing work can be simplified.

Japanese Utility Model Publication No. 7-37562

  By the way, in order to appropriately perform electrolytic dressing on the grindstone surface, not only a sufficient electrolytic solution is supplied between the grindstone surface and the electrode surface, but also the distance between the grindstone surface and the electrode surface is kept constant. This is very important. That is, in order to suppress the variation in the dressing condition at each part on the surface of the grindstone, it is important to make the amount of the electrolyte solution present between the grindstone surface and the electrode surface uniform. If unevenness occurs in the amount of electrolyte present between the grinding wheel surface and the electrode surface, the energization resistance changes locally, resulting in variations in the amount of electrolysis of the bond material, leading to the shape deformation of the grinding wheel surface. I was supposed to. Such shape deformation of the grindstone surface is a factor that lowers the grinding accuracy of a workpiece such as a camshaft. Therefore, it is desired to make the amount of electrolyte present between the grindstone surface and the electrode surface uniform. Yes.

  An object of the present invention is to suppress the shape deformation of the grindstone surface due to electrolytic dressing and to improve the grinding accuracy of the workpiece.

  The electrolytic dressing apparatus of the present invention is an electrolytic dressing apparatus that performs electrolytic dressing on a grinding surface provided on the outer periphery of a disc-shaped grindstone, and includes an electrode member having an arcuate electrode surface facing the grinding surface, and the grinding surface And an electrolyte supply means for supplying an electrolyte between the electrode surface and a voltage applying means for applying a voltage to the grinding surface and the electrode surface, on one end side in the longitudinal direction of the electrode surface A first partition member that protrudes toward the grinding surface from the electrode surface is attached, and a second partition member that protrudes toward the grinding surface from the electrode surface is attached to the other end in the longitudinal direction of the electrode surface. A flow path for guiding the electrolytic solution is opened on the electrode surface between the first partition member and the second partition member.

  The electrolytic dressing apparatus according to the present invention is characterized in that the protruding amounts of the first and second partition members from the electrode surface are the same.

  The electrolytic dressing apparatus of the present invention is characterized in that the first and second partition members are formed using a ceramic material.

  According to the present invention, the first partition member and the second partition member projecting from the electrode surface to the grinding surface side are attached to the electrode member having the electrode surface facing the grinding surface of the disc-shaped grindstone, and the electrolytic solution is added. A channel to be guided is opened on the electrode surface between the first partition member and the second partition member. Accordingly, the distance between the electrode surface and the grinding surface can be kept constant, and variations in the amount of electrolyte present between the electrode surface and the grinding surface can be suppressed. Thereby, it becomes possible to suppress the shape deformation of the grindstone surface due to the electrolytic dressing, and it is possible to improve the grinding accuracy of the workpiece.

It is the schematic which shows the grinding machine of the cam shaft provided with the electrolytic dressing apparatus which is one embodiment of this invention. (a) is a top view which shows a dress unit, (b) is a side view which shows a dress unit from the arrow A direction of Fig.2 (a). (a) is a side view showing an electrode unit provided in the dress unit of FIG. 2 (b), and (b) is a front view showing the electrode unit from the direction of arrow A in FIG. 3 (a). (a) is a side view which shows an electrode unit in the state which removed the cover member, (b) is a front view which shows an electrode unit from the arrow A direction of Fig.4 (a). It is explanatory drawing which shows the positional relationship of an electrode member and a rotating grindstone. (a) And (b) is a diagram which shows the cross-sectional curve of the cam surface ground by the rotating grindstone. It is a comparison figure which shows the arithmetic mean roughness of a cam surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a grinding machine 12 of a camshaft 11 provided with an electrolytic dressing apparatus 10 according to an embodiment of the present invention. As shown in FIG. 1, the grinding machine 12 has a bed 13, and a processing table 14 for fixing the camshaft 11 as a work is provided on the bed 13. The machining table 14 is movable in the arrow Z direction, and the machining table 14 is slidable in the arrow Z direction by a motor 15 assembled to the bed 13. A spindle stock 16 and a tailstock 17 are installed on the machining table 14, and the camshaft 11 is fixed on the machining table 14 by sandwiching the camshaft 11 between the spindle stock 16 and the tailstock 17. Note that a motor 18 is incorporated in the headstock 16 so that the camshaft 11 can be rotated on the processing table 14.

  The bed 13 of the grinding machine 12 is provided with a grindstone table 21 provided with a disc-shaped rotating grindstone (disk-shaped grindstone) 20. The grindstone table 21 is movable in the direction of arrow X, and the grindstone table 21 can be slid in the direction of arrow X by the motor 22 assembled to the bed 13. The grindstone table 21 is provided with a rotary grindstone 20 and a motor 23 that rotationally drives the grindstone 20. In order to control the plurality of motors 15, 18, 22, and 23 provided in the grinding machine 12, the grinding machine 12 is provided with a control unit 24 including a CPU, a memory, and the like. A control signal is output to each motor according to the control program. Thereby, according to a predetermined control program, while the processing table 14 and the grindstone table 21 can be slid, the camshaft 11 on the processing table 14 can be rotated, and the cam surface (cam profile) of the camshaft 11 is rotated by the rotating grindstone 20. ) 11a can be ground.

  When clogging or the like occurs in the rotary grindstone 20, the grinding accuracy of the camshaft 11 is lowered. Therefore, the electrolytic dressing device 10 is assembled in the grinding machine 12, and the rotary grindstone 20 that grinds the camshaft 11. Electrolytic dressing (sharpening) is applied continuously. The electrolytic dressing apparatus 10 includes a dress unit 30 installed on the grindstone table 21 and a dress control unit (voltage applying unit) 31 incorporated in the control unit 24. The dress unit 30 is provided with an electrode member 32 close to the outer periphery of the rotating grindstone 20, and a negative electrode terminal 33 extending from the dress control unit 31 is connected to the electrode member 32. Further, the rotating grindstone 20 is constituted by a so-called metal bond grindstone, and a positive electrode terminal 34 extending from the dress control unit 31 is connected to the rotating grindstone 20. Further, a pump 35 as an electrolytic solution supply means is connected to the dress unit 30, and coolant (electrolytic solution, conductive grinding fluid) is supplied from the pump 35 into the dress unit 30. The dress control unit 31 of the control unit 24 supplies a coolant to the dress unit 30 and applies a pulse voltage to the electrode member 32 and the rotating grindstone 20. Thereby, the bond material of the rotating grindstone 20 can be removed by electrolysis, and the rotating grindstone 20 can be dressed. The metal bond grindstone is, for example, a grindstone in which abrasive grains such as diamond, cBN (cubic boron nitride), aluminum oxide, silicon carbide, and silicon dioxide are bonded with a bond material mainly composed of bronze, cast iron, or the like. is there.

  2A is a plan view showing the dress unit 30, and FIG. 2B is a side view showing the dress unit 30 from the direction of arrow A in FIG. 2A. 3A is a side view showing the electrode unit 41 included in the dressing unit 30 in FIG. 2B, and FIG. 3B shows the electrode unit 41 from the direction of arrow A in FIG. It is a front view. 4A is a side view showing the electrode unit 41 with the cover member 44 removed, and FIG. 4B is a front view showing the electrode unit 41 from the direction of arrow A in FIG. is there.

  As shown in FIGS. 2A and 2B, the dress unit 30 has a housing 40 that covers a part of the rotating grindstone 20, and an electrode that is close to the grinding surface 20 a of the rotating grindstone 20 in the housing 40. A unit 41 is provided. The electrode unit 41 is held by a positioning mechanism 42, and the electrode unit 41 can be positioned and fixed by operating the positioning mechanism 42. As shown in FIGS. 3A and 3B, the electrode unit 41 includes a resin base member 43 fixed in the housing 40, a metal electrode member 32 fixed to the base member 43, And a resin cover member 44 fixed so as to cover the side surface of the electrode member 32. Thus, the electrode unit 41 in which the electrode member 32 is sandwiched between the base member 43 and the cover member 44 has a substantially U-shaped cross-sectional shape, and the electrode unit 41 rotates as shown in FIG. It is installed so as to partially cover the outer periphery of the grindstone 20.

As shown in FIGS. 4A and 4B, the electrode member 32 of the electrode unit 41 has an arcuate electrode surface 32 a that faces the grinding surface 20 a of the rotating grindstone 20. A block member 51 as a first partition member is attached to one end side in the longitudinal direction of the electrode surface 32a, and a block member 52 as a second partition member is attached to the other end side in the longitudinal direction of the electrode surface 32a. It has been. In other words, the block member 51 is attached to the upstream electrode surface 32a in the rotation direction of the rotary grindstone 20, and the block member 52 is attached to the electrode surface 32a downstream in the rotation direction of the rotary grindstone 20. Yes. These block members 51 and 52 are formed using an insulating ceramic material. As the ceramic material, alumina (aluminum oxide, Al ₂ O ₃ ), sialon (Si—Al—O—N compound), or the like can be used. The block members 51 and 52 protrude from the electrode surface 32a toward the grinding surface 20a, and the protrusion amounts Ha and Hb of the block members 51 and 52 are set to the same value. The electrode member 32 is formed with a coolant flow path (flow path) 53 through which coolant is guided. The coolant flow path 53 is formed to open to the electrode surface 32 a between the block members 51 and 52. . Further, a supply port 54 communicating with the coolant channel 53 is formed on the side surface of the electrode member 32, and a pipe (not shown) extending from the pump 35 is connected to the supply port 54. Note that a tapered portion 53a that gradually enlarges the cross-sectional area of the coolant channel 53 is formed at the opening of the coolant channel 53 formed on the electrode surface 32a.

  FIG. 5 is an explanatory view showing the positional relationship between the electrode member 32 and the rotating grindstone 20. As shown in FIG. 5, when the electrode unit 41 is installed in the vicinity of the rotating grindstone 20, the block members 51 and 52 of the electrode member 32 included in the electrode unit 41 are abutted against the grinding surface 20 a of the rotating grindstone 20. After that, the electrode unit 41 is pulled apart and fixed by a predetermined amount outward in the radial direction of the rotating grindstone 20. That is, as shown in the enlarged portion of FIG. 5, the surfaces of the block members 51 and 52 and the grinding surface 20a of the rotating grindstone 20 are opposed to each other with a minute gap. Thus, when positioning the electrode unit 41 with respect to the rotating grindstone 20, by utilizing the pair of block members 51 and 52 that protrude from the electrode surface 32a with the same protrusion amounts Ha and Hb, It becomes possible to keep constant the space | interval of the electrode surface 32a and the grinding surface 20a of the rotary grindstone 20 over the whole region.

  Further, since the two block members 51 and 52 protrude from the electrode surface 32a, one region α is defined by the two block members 51 and 52 between the electrode surface 32a and the grinding surface 20a. Further, since the coolant channel 53 opens in the electrode surface 32a located between the block members 51 and 52, as shown by an arrow A in FIG. 5, the region α defined by the block members 51 and 52 is filled with coolant. It becomes possible to satisfy. In addition, since the base member 43 and the cover member 44 which comprise the electrode unit 41 are extended to the rotating grindstone 20 side so that the side surface of the rotating grindstone 20 may be followed, the leak of a coolant is suppressed and the inside of area | region (alpha) is filled with coolant. Is possible.

  As described above, by providing the two block members 51 and 52 protruding from the electrode surface 32a, the distance between the electrode surface 32a and the grinding surface 20a can be kept constant over the entire region. In addition, two block members 51 and 52 projecting from the electrode surface 32 a are provided, and the coolant channel 53 is opened in the electrode surface 32 a located between the block members 51 and 52, thereby being partitioned by the block members 51 and 52. It is possible to fill the region α with the coolant. As a result, variation in the amount of coolant interposed between the electrode surface 32a and the grinding surface 20a can be suppressed, and the amount of electrolysis of the bond material of the rotating grindstone 20 during electrolytic dressing can be made uniform. . Thus, since the grinding surface 20a of the rotating grindstone 20 can be uniformly dressed, it is possible to prevent the grinding surface 20a from being deformed and to improve the grinding accuracy of the camshaft 11. In addition, since the block members 51 and 52 have insulation, the electric current for electrolytic dressing does not flow through the block members 51 and 52.

  Further, the coolant adhering to the grinding surface 20a of the rotating grindstone 20 in the region α is removed to an appropriate amount by the block member 52 provided on the downstream side in the rotation direction of the rotating grindstone 20. Thus, by removing the coolant necessary for electrolysis outside the region α and preventing unnecessary diffusion of the coolant, it is possible to limit the region α that is electrolyzed by the electrolytic dressing. Accordingly, since the electrolytic dressing outside the region α can be reliably prevented, the grinding surface 20a can be prevented from being deformed and the grinding accuracy of the camshaft 11 can be increased.

  Here, FIGS. 6A and 6B are diagrams showing a cross-sectional curve of the cam surface 11 a ground by the rotating grindstone 20. 6A and 6B, the vertical axis shows the displacement in the height direction of the cam surface 11a, and the horizontal axis shows the displacement in the width direction of the cam surface 11a (the axial direction of the cam shaft 11). ing. The cam surface 11a shown in FIG. 6 (a) is a cam surface 11a ground by using the rotating grindstone 20 subjected to electrolytic dressing by the electrolytic dressing apparatus 10 of the present invention having the block members 51 and 52. On the other hand, the cam surface 11a shown in FIG. 6B is a cam surface 11a ground by using the rotating grindstone 20 that has been subjected to electrolytic dressing by a conventional electrolytic dressing apparatus that does not have the block members 51 and 52. FIG. 7 is a comparative diagram showing the arithmetic average roughness Ra of the cam surface 11a. The arithmetic average roughness indicated by the circles in FIG. 7 is the arithmetic average roughness of the cam surface 11a ground by using the rotating grindstone 20 subjected to electrolytic dressing by the electrolytic dressing apparatus 10 of the present invention having the block members 51 and 52. It is. On the other hand, the arithmetic mean roughness indicated by the filled square marks in FIG. 7 is the arithmetic value of the cam surface 11a ground by using the rotating grindstone 20 subjected to electrolytic dressing by a conventional electrolytic dressing apparatus having no block members 51 and 52. Average roughness.

  As shown in FIG. 6A, when the electrolytic dressing apparatus 10 of the present invention is used, the cross-sectional curve of the cam surface 11a appears almost horizontally within a narrow amplitude range. Therefore, it is considered that the grinding surface 20a of the rotating grindstone 20 obtained by grinding the cam surface 11a also suppresses the shape deformation of the grindstone surface and moderately suppresses the surface roughness of the grindstone surface. That is, it is considered that the electrolytic dressing for the rotating grindstone 20 is appropriately performed. On the other hand, as shown in FIG. 6B, when the conventional electrolytic dressing apparatus is used, the amplitude of the cross-sectional curve of the cam surface 11a gradually widens, and the cross-sectional curve of the cam surface 11a gradually inclines. Appears. Therefore, it is considered that the grinding surface 20a of the rotating grindstone 20 obtained by grinding the cam surface 11a also has the shape of the grindstone surface deformed and the surface of the grindstone is also roughened. That is, it is considered that the electrolytic dressing for the rotating grindstone 20 is not properly performed.

  Further, as shown in FIG. 7, when the conventional electrolytic dressing apparatus is used, the arithmetic average roughness Ra of the cam surface 11a approaches 0.6 when the seven camshafts 11 are ground. Yes. On the other hand, when the electrolytic dressing apparatus 10 of the present invention is used, about 40 camshafts 11 can be ground until the arithmetic average roughness Ra of the cam surface 11a reaches 0.6. That is, by using the electrolytic dressing apparatus 10 of the present invention, the grinding surface 20a of the rotating grindstone 20 can be appropriately dressed, so that the number of processing can be greatly increased while maintaining the grinding quality of the camshaft 11. It has become.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above description, the camshaft 11 is used as a workpiece. However, the present invention is not limited to this, and the electrolytic dressing apparatus 10 of the present invention may be applied to a grindstone for grinding other workpieces. In the above description, the two block members 51 and 52 are attached to the electrode member 32, but three or more block members may be attached to the electrode member 32. In the above description, the coolant flow path 53 is opened from two places on the electrode surface 32a. However, the present invention is not limited to this, and the coolant flow path 53 may be opened from one place. Alternatively, the coolant channel 53 may be opened. Furthermore, in the above description, the electrolytic dressing is continuously performed on the rotary grindstone 20, but the present invention is not limited to this, and the electrolytic dressing may be performed every preset processing time or every number of processings. good.

10 Electrolytic dressing device 20 Rotary whetstone (disc-shaped whetstone)
20a Grinding surface 31 Dress control unit (voltage application means)
32 Electrode member 32a Electrode surface 35 Pump (electrolyte supply means)
51 Block member (first partition member)
52 Block member (second partition member)
53 Coolant channel (channel)
Ha, Hb Protrusion

Claims (3)

An electrolytic dressing device that performs electrolytic dressing on a grinding surface provided on the outer periphery of a disc-shaped grindstone,
An electrode member comprising an arcuate electrode surface facing the grinding surface;
An electrolyte supply means for supplying an electrolyte between the ground surface and the electrode surface;
Voltage application means for applying a voltage to the grinding surface and the electrode surface;
A first partition member that protrudes toward the grinding surface rather than the electrode surface is attached to one end side in the longitudinal direction of the electrode surface,
At the other end side in the longitudinal direction of the electrode surface, a second partition member protruding to the grinding surface side from the electrode surface is attached,
An electrolytic dressing apparatus, wherein a flow path for guiding the electrolytic solution is opened on the electrode surface between the first partition member and the second partition member. The electrolytic dressing apparatus according to claim 1,
The electrolytic dressing apparatus characterized in that the protruding amounts of the first and second partition members from the electrode surface are the same. The electrolytic dressing apparatus according to claim 1 or 2,
The electrolytic dressing apparatus, wherein the first and second partition members are formed using a ceramic material.

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