JP5181799B2 - Whetstone - Google Patents

Description

  The present invention relates to a grindstone in which a grindstone layer is formed on an outer periphery, and a workpiece is ground while supplying a grinding liquid toward a contact surface between the outer circumferential surface of the grindstone layer and the workpiece.

  Conventionally, when grinding a workpiece with a grindstone provided in a grinding machine, the grinding fluid is supplied to the grinding point between the grindstone and the workpiece, cooled and lubricated, thereby grinding and burning the workpiece by grinding heat and thermal distortion. Etc. are prevented. However, when grinding fluid is supplied toward the grinding point between the grinding wheel and the workpiece, dynamic pressure is generated in the grinding fluid between the grinding wheel and the workpiece, and when there are holes or grooves in the workpiece. The pressure changes due to the holes and grooves, causing relative displacement between the grindstone and the workpiece, resulting in a problem that the grinding accuracy of the workpiece is lowered. A technique for preventing a decrease in grinding accuracy due to dynamic pressure generated in such a grinding fluid is disclosed in Patent Document 1.

In the technique described in Patent Document 1, a grinding fluid supply device that can switch the grinding fluid pressure supplied to the coolant nozzle that supplies the grinding fluid to the grinding point where the grinding wheel and the workpiece are in contact with each other in two stages, high and low, is provided. The grinding fluid pressure deteriorates due to the dynamic pressure generated in the grinding fluid by switching the grinding fluid pressure to high during rough grinding where the feed rate to the workpiece is high, and switching to low pressure during finish grinding and spark-out grinding where the feed rate is low. Is preventing.
Japanese Utility Model Publication No. 57-157458 (page 1-3, FIG. 2)

  In the above prior art, it is not possible to release the dynamic pressure generated in the grinding fluid supplied toward the contact surface where the grinding surface of the grindstone and the workpiece contact, and in particular, the rotational speed of the grindstone and the workpiece is increased. When the grinding efficiency is increased, the grinding accuracy is deteriorated by the dynamic pressure generated in the grinding fluid. Therefore, the present applicant has proposed a grindstone provided with at least one inclined groove so as to vertically penetrate a contact surface where the grindstone and the workpiece come into contact with each other. According to such a grindstone, the drainage of the grinding fluid supplied toward the contact surface is improved, the contact arc length of the grindstone with respect to the workpiece is reduced, the dynamic pressure generated in the grinding fluid is released, and the workpiece The processing accuracy can be increased. However, by providing the inclined grooves, the abrasive volume (number of abrasive grains) acting on the grinding of the grinding wheel is reduced, so that the life of the grinding wheel may be shortened, and the work frequency of grinding wheel replacement in the grinding machine increases.

  The present invention is to provide a long-life grindstone capable of grinding a workpiece with high accuracy.

In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that a grindstone layer is formed on the outer periphery, and the grinding liquid is directed toward the contact surface between the outer peripheral surface of the grindstone layer and the workpiece. In the grindstone that grinds the workpiece while supplying,
The inner circumferential surface of the grinding wheel layer is inclined at a predetermined angle with respect to the grinding wheel circumferential direction , and a plurality of inclined grooves are engraved at equal intervals.
When the intersection of the inclined groove and the extension line of one edge parallel to the grinding wheel circumferential direction of the contact surface is defined as one intersection point and the intersection point of the other edge extension line is defined as the other intersection point, The other intersection and the one intersection of one inclined groove and the adjacent inclined groove overlap by a predetermined overlap amount in the grinding wheel circumferential direction,
When the inclined grooves appear on the outer peripheral surface of the grindstone layer due to wear of the grindstone layer, the grindstone circumferential length of the contact surface is smaller than the overlap amount of the grindstone with respect to the workpiece. That is, at least one of the cutting depth and the inclination angle and interval of the inclined groove is set .

A structural feature of the invention according to claim 2 is that in the grindstone according to claim 1, the grindstone layer is located on a circumference within a contact surface between the outer peripheral surface of the grindstone layer and the workpiece. That is, the sum of the widths of the inclined grooves existing on the cutting line when cutting in parallel with the grindstone axis at the arbitrary position and in the direction of the grindstone diameter is always equal .

, The feature in construction of the invention according to claim 3, claim Te grindstone smell according to 1 or 2, tilt the previous SL groove width toward the outer peripheral side from the inner peripheral surface of the grinding wheel layer is gradually reduced The groove is engraved.
A structural feature of the invention according to claim 4 is that, in the grindstone according to claim 1 or 2 , a plurality of inclined grooves having different groove depths from the inner peripheral surface side of the grindstone layer are formed. That is.

  According to the invention according to claim 1, a grindstone layer is formed on the outer periphery, and in the grindstone for grinding a workpiece while supplying a grinding liquid toward the contact surface between the outer peripheral surface of the grindstone layer and the workpiece, Since the inclined groove is engraved on the inner peripheral surface of the grindstone layer, it acts in the same manner as a general grindstone until it reaches the bottom of the inclined groove from the outer peripheral surface of the grindstone layer. That is, when the grindstone is first used, chips generated during grinding or truing are hardly clogged with pores existing between the abrasive grains, so that the grindstone surface of the grindstone and the work surface are in contact with each other. Thus, the dynamic pressure generated in the supplied grinding fluid can be released, and high-precision grinding can be performed. Further, at the beginning of the use of the grindstone, the abrasive volume (number of abrasive grains) acting on the grinding of the grindstone is increased by the absence of the inclined grooves, so that the life is long. However, if the grindstone is used as it is, the chips will clog the pores (clogging), so the dynamic pressure generated in the grinding fluid cannot be released and the grinding accuracy will decrease, but the grindstone layer will wear out. When the inclined grooves appear, the dynamic pressure generated in the grinding fluid can be released by the following action, and high-precision grinding can be performed.

  That is, the grinding fluid supplied from above flows out from above and below through the inclined groove, and the dynamic pressure of the grinding fluid generated between the grinding surface and the workpiece can be released. As a result, even if the supply amount of the grinding fluid is not reduced, the workpiece is displaced in the direction away from the grindstone due to the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies so that the workpiece is removed from the grindstone. The separation distance does not change, and the grinding accuracy of the workpiece can be increased.

In particular , when the intersection of the inclined groove and the extension line of one edge parallel to the circumferential direction of the grinding wheel of the contact surface is defined as one intersection point, and the intersection point of the extension line of the other edge is defined as the other intersection point, one inclined groove And the other intersection of one inclined groove and one intersection of the adjacent inclined grooves overlap each other by a predetermined overlap amount in the grinding wheel circumferential direction, and the grinding wheel circumferential length of the contact surface is smaller than the overlap amount. Therefore, at least one inclined groove penetrates the contact surface where the grinding surface of the grindstone and the workpiece come into contact in the vertical direction, and the grinding fluid supplied from above passes through the inclined groove from above and below. The dynamic pressure of the grinding fluid that flows out and is generated between the grinding surface and the workpiece can be released. As a result, even if the supply amount of the grinding fluid is not reduced, the workpiece is displaced in the direction away from the grindstone due to the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies so that the workpiece is removed from the grindstone. The separation distance does not change, and the grinding accuracy of the workpiece can be increased.

According to the invention of claim 2 , the effect of reducing the dynamic pressure generated in the grinding fluid by the inclined groove is proportional to the width of the inclined groove, but the inclined groove has a constant width over the entire circumference of the grinding surface. As a result, the effect of reducing the dynamic pressure is constant over the entire circumference of the grinding surface, and the workpiece can be ground without unevenness.

According to the invention which concerns on Claim 3 , since the inclination groove | channel which groove width (groove area) reduces gradually toward the outer peripheral surface side from the inner peripheral surface side of a grindstone layer, use of a grindstone advances. Accordingly, the groove width (groove area) is increased. Therefore, even if clogging increases as the use of the grindstone progresses, the groove width (groove area) gradually increases, so the dynamic pressure of the grinding fluid can be effectively released, and the grinding accuracy of the workpiece Can be increased.

According to the invention which concerns on Claim 4 , since the several inclined groove from which the groove depth from the inner peripheral surface side of a grindstone layer differs is engraved, the number of the inclined grooves which appear as the use of a grindstone progresses increases. Will do. Therefore, even if clogging increases as the use of the grindstone progresses, the number of inclined grooves gradually increases, so the dynamic pressure of the grinding fluid can be effectively released, and the grinding accuracy of the workpiece can be improved. Can do.

  Hereinafter, a grindstone according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a grindstone 10 including a segment-type grindstone chip (grindstone layer) 11. The grindstone chip 11 of the grindstone 10 is formed with an abrasive grain layer 12 formed by bonding superabrasive grains with vitrified bonds on the outside. A base layer 13 that does not include abrasive grains is integrally formed on the inner side of the abrasive grain layer 12. In the grindstone 10, a plurality of arc-shaped grindstone chips 11 composed of an abrasive grain layer 12 and an underlayer 13 are arranged on the outer peripheral surface of a disk-shaped core 14 formed of a metal such as iron or aluminum, or a resin. The base layer 13 is configured to be adhered to the core 14 with an adhesive on the bottom surface. A plurality of inclined grooves 20 are formed on the inner peripheral surface 18 of the grindstone chip 11 from the bottom surface of the underlayer 13 to the middle of the abrasive layer 12, that is, from the bottom of the inclined groove 20 to the upper surface of the abrasive layer 12. Is engraved so as to have a predetermined thickness.

FIG. 2 shows an arc-shaped grindstone tip 11, and the abrasive grain layer 12 is formed by bonding superabrasive grains 16 such as CBN and diamond to a thickness of 3 mm to 5 mm with vitrified bonds 17. For adjustment, particles such as aluminum oxide (Al ₂ O ₃ ) may be mixed as an aggregate instead of superabrasive grains. The underlayer 13 is formed by bonding the underlayer particles 19 with a vitrified bond 17 to a thickness of 1 mm to 3 mm. Further, the thickness T from the bottom of the inclined groove 20 to the upper surface of the abrasive layer 12 is such that clogging is allowed when the abrasive layer 12 is worn and reaches the bottom of the inclined groove 20 as a new grindstone 10 is used. For example, in the case of the abrasive grain layer 12 of the CBN abrasive grain of # 120, it is 1 mm. When vitrified bond 17 is employed, the chip characteristics are excellent due to the characteristics of the pores, and the sharpness is improved, so that the amount of grinding wheel wear can be reduced and grinding can be performed to a good surface roughness. Further, as the binder, in addition to the vitrified bond 17, a resin bond, a metal bond, or the like can be used.

  The grindstone 10 is attached by a core 14 to a grindstone shaft 32 that is supported on a grindstone base 31 of a grinder 30 shown in FIG. A workpiece W is rotatably supported on the workpiece support device 33 of the grinding machine 30, and the grinding surface 15 (the outer peripheral surface of the grinding wheel tip 11) formed on the abrasive layer 12 of the grinding wheel 10 by the advance of the grinding wheel base 31. Comes into contact with the workpiece W at the contact surface S to grind the outer peripheral surface of the workpiece W. The grindstone 10 grinds the workpiece W with a normal grinding surface 15 having no inclined groove 20 in the initial stage of use, but the inclined groove 20 in the middle period of use in which wear has progressed due to repeated grinding and truing cycles. The workpiece W is ground on the grinding surface 15 where the mark appears.

  That is, the grindstone 10 acts in the same manner as a general grindstone until it reaches the bottom of the inclined groove 20 from the outer peripheral surface of the grindstone chip 11, but in such an initial stage of use, chips generated during grinding or truing are ground. Since the pores existing between the grains are almost not clogged, the dynamic pressure generated in the grinding fluid supplied toward the contact surface where the grinding surface 15 of the grindstone 10 and the workpiece W come into contact can be released. Accurate grinding can be performed. Furthermore, since the abrasive volume (number of abrasive grains) acting on the grinding process of the grindstone 10 is increased by the absence of the inclined groove 20 in the initial use of the grindstone 10, the life of the grindstone can be extended.

  However, in the middle period of use where wear has progressed due to repeated grinding and truing cycles, chips clog the pores (clogging). For example, the # 120 CBN abrasive grain size is 125 μm, and the pores are about the same size, but the truing cycle is clogged due to, for example, 10 μm (2.5 μm × 4 times) on one side. It is almost impossible to remove chips. Therefore, the dynamic pressure generated in the grinding fluid cannot be released and the grinding accuracy is lowered. However, when the abrasive grain layer 12 is worn, the inclined groove 20 appears and the grinding fluid is operated by the action described below. Thus, the dynamic pressure generated can be released, and high-precision grinding can be performed.

  As shown in FIGS. 4 to 6, on the inner peripheral surface 18 of the grindstone tip 11 of the grindstone 10, the depth h from which the plurality of inclined grooves 20 reach the inside of the abrasive grain layer 12 from the bottom surface of the foundation layer 13. Thus, the base layer 13 and the abrasive grain layer 12 are provided through the both sides 21 and 22 of the base layer 13 and the abrasive grain layer 12 parallel to the circumferential direction of the grindstone. That is, a plurality of inclined grooves 20 inclined by a predetermined inclination angle α with respect to the circumferential direction of the grindstone are formed on the inner peripheral surface 18 of the grindstone chip 11 at a predetermined pitch P at equal intervals and with the inclined grooves 20. When the intersection point of the contact surface S with the extension line 23 of one edge Sa parallel to the circumferential direction of the grindstone is defined as one intersection point 20a and the intersection point with the extension line 24 of the other edge Sb is defined as the other intersection point 20b, The other intersection 20b of the inclined groove 20 and the one intersection 20a of the inclined groove 20 adjacent to the one inclined groove 20 are engraved so as to overlap by the overlap amount V in the circumferential direction of the grindstone.

  Then, the grinding wheel circumferential length L of the contact surface S between the grinding surface 15 and the workpiece W when the inclined groove 20 appears due to the progress of wear due to the grinding cycle or truing cycle of the grinding wheel 10 from the overlap amount V. Also, at least one of the cutting amount t of the grindstone 10 with respect to the workpiece W, the inclination angle α and the interval (pitch) P of the inclined groove 20 is set. The contact surface S is an area of the grinding surface 15 of the grindstone 10 defined by the intersection point between the outer circumference circle of the grindstone 10 and the outer circumference circle of the workpiece W and the width A of the workpiece W. It is surrounded by the parallel one edge Sa, the other edge Sb, and the one edge Sf and the other edge Sr parallel to the grinding wheel axis direction.

  Since the grinding wheel circumferential length L of the contact surface S between the grinding surface 15 of the grindstone 10 and the workpiece W is smaller than the overlap amount V, the grinding liquid supplied to the contact surface S from above is contact surface. It is possible to release the dynamic pressure of the grinding fluid which flows out from above and below through the inclined groove 20 penetrating S and is generated between the grinding surface 15 and the workpiece W. As a result, the workpiece W is displaced in the direction away from the grindstone 10 by the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies to change the distance at which the workpiece W is separated from the grindstone 10. Thus, the grinding accuracy of the ground workpiece W can be increased.

As is apparent from FIGS. 4 and 6 in which the grinding surface 15 of the grindstone 10 is developed, one inclined groove 20 intersects the extension line 24 of the other edge Sb of the contact surface S, and the other intersection 20b. The amount of overlap V in which the slanting groove 20 adjacent to the slanting groove 20 intersects the extension line 23 of one edge Sa of the contact surface S and the one intersection 20a overlaps in the circumferential direction of the grindstone, and the slanting of the slanting groove 20 The relationship between the angle α, the interval P between adjacent inclined grooves 20, for example, the circumferential pitch, and the width A of the workpiece W that is the axial length of the contact surface S is as follows:
V = A / tan α−P (1)
It becomes.

Therefore, the condition where the circumferential length L of the contact surface S is smaller than the overlap amount V,
L <A / tan α-P (2)
Is satisfied, regardless of the rotational phase of the grindstone 10, at least one inclined groove 20 penetrates the contact surface S in the vertical direction, and the grinding surface 15 and the workpiece W are brought into contact with the grinding fluid flowing into the contact surface S. Can be released from both above and below the contact surface S. On the other hand, if this condition is not satisfied, depending on the rotational phase of the grindstone 10, none of the inclined grooves 20 penetrates the contact surface S in the vertical direction, that is, the inclined grooves 20 are upward with respect to the contact surface S. If it is only opened, the dynamic pressure is not released below the contact surface S. Similarly, if the inclined groove 20 is opened only downward, the dynamic pressure of the grinding fluid is not released above the contact surface S.

  The grinding wheel circumferential length L of the contact surface S where the grinding wheel 10 contacts the workpiece W is an intersection where the outer circumferential circle of the grinding wheel 10 and the outer circumferential circle of the workpiece W intersect as shown in FIG. The length of the connecting line segment. Since the length L of the contact surface S in the circumferential direction of the grindstone is extremely smaller than the diameters of the grindstone 10 and the workpiece W, a line segment that connects the intersections of the outer circle of the grindstone 10 and the outer circle of the workpiece W intersects. Can be approximated by the length of

If the radius of the workpiece W is R1, the radius of the grindstone 10 is R2, and the cutting depth of the grindstone 10 into the workpiece W is t, as shown in FIG. 7 (c), the distance between the center of the workpiece W and the grindstone 10 The distance C is
C = R1 + R2-t (3)
It becomes. A line segment perpendicular to the line segment EF connecting the center E of the work piece W and the center F of the grindstone 10 from the intersection point D where the outer circumference circle of the grindstone 10 and the outer circumference circle of the work piece W intersect with the line segment EF. Let H be the point to do, and let the lengths of the line segments DH, EH, and FH be x, y, and z, respectively.
R1 ² = x ² + y ² (4)
R2 ² = x ² + z ² (5)
And
C = y + z to y ² = (C−z) ² (6)
It becomes. Solving equations (4), (5), and (6) for x,
x = √ (R2 ² − ((C ² + R2 ² −R1 ² ) / 2C) ² ) (7)
It becomes. And the circumferential direction length L of the contact surface S where the grindstone 10 contacts the workpiece W is:
L = 2x (8)
It becomes.

When the circumferential length L of the contact surface S is equal to the overlap amount V, from the equations (1) and (8),
L = 2x = V = A / tan α−P, and the cutting amount t0 at that time is
t0 = R1 + R2-√ (R1 ² − ((A / tan α−P) / 2) ² )
-√ (R2 ² -((A / tan α-P) / 2) ² ) (9)
It becomes. Therefore, when the radii R1, R2 of the workpiece W and the grindstone 10, the width A of the workpiece W, the inclination angle α of the inclined groove 20 and the circumferential pitch P are determined, the cutting of the grindstone 10 into the workpiece W is performed. When the amount t is set smaller than t0, the circumferential length L of the contact surface S becomes smaller than the overlap amount V.

  Further, one of the radii R1 and R2 of the workpiece W and the grindstone 10, the width A of the workpiece W, the cutting amount t of the grindstone 10 into the workpiece W, and the inclination angle α and the circumferential pitch P of the inclined groove 20 are determined. If determined, the other of the inclination angle α0 and the circumferential pitch P0 of the inclined groove 20 is set so that the formula (9) is established, and the circumferential pitch P or the inclination angle α is set to the set circle. If the pitch is set smaller than the circumferential pitch P0 or the inclination angle α0, the circumferential length L of the contact surface S becomes smaller than the overlap amount V. The number n of the inclined grooves 20 set in this way is n = 2π × R2 / P.

  Next, a method for grinding the workpiece W using the grindstone 10 according to the present embodiment will be described. The grindstone 10 is mounted on a grindstone shaft 32 supported on a grindstone base 31 of a grinding machine 30 shown in FIG. 3 by a core 14 and is driven to rotate, and the workpiece W is applied to a workpiece support device 33 including a headstock and a tailstock. It is supported and rotated. Grinding fluid is supplied from the coolant nozzle 35 attached to the grindstone cover 34 toward the contact surface S between the grinding surface 15 of the grindstone 10 and the workpiece W, and the grindstone base 31 is ground and fed toward the workpiece W. The workpiece W is ground by the grindstone 10.

  In the initial stage of use of the grindstone 10, the inclined grooves 20 do not appear on the grinding surface 15, but the chips generated during grinding or truing are hardly clogged in the pores existing between the abrasive grains. The dynamic pressure generated in the grinding liquid supplied toward the contact surface where the surface 15 and the workpiece W come into contact can be released, and the workpiece W is ground with high accuracy. At this time, in the initial use of the grindstone 10, the abrasive volume (number of abrasive grains) acting on the grinding process of the grindstone 10 is increased by the absence of the inclined grooves 20, so that the service life is long.

  In the middle period of use of the grindstone 10, the chips start to clog the pores (clogging), but the inclined grooves 20 appear on the grinding surface 15 and the dynamic pressure generated in the grinding liquid can be released. That is, regardless of the rotational phase of the grindstone 10, at least one inclined groove 20 penetrates the contact surface S in the vertical direction, so that the dynamic pressure of the grinding fluid generated between the grinding surface 15 and the workpiece W is contacted. The surface S can be opened from above and below. Thereby, the workpiece W is displaced in the direction away from the grindstone 10 by the dynamic pressure generated in the grinding fluid, or the distance at which the workpiece W is separated from the grindstone 10 is changed due to the change in the dynamic pressure generated in the grinding fluid. The workpiece W is ground with high accuracy.

  For example, as shown in FIG. 8, when a cam including a base circle portion Wb, a top portion Wt, and a pair of lift portions Wl connecting the base circle portion Wb and the top portion Wt is ground, the cam lift portion Wl has a curvature. Therefore, the circumferential length of the contact surface S with the grindstone 10 is the longest. As described above, when the circumferential length of the contact surface S is increased, the dynamic pressure of the grinding fluid supplied toward the contact surface S is increased. However, by making the overlap amount V of the adjacent inclined grooves 20 larger than the longest circumferential direction length of the grindstone, at least one inclined groove 20 forms the contact surface S regardless of the rotational phase of the grindstone 10. Since it penetrates in the vertical direction, the dynamic pressure of the grinding fluid generated between the grinding surface 15 and the workpiece W can be released from above and below the contact surface S. As a result, even if the supply amount of the grinding fluid is not reduced in finish grinding, the cam is displaced in a direction away from the grindstone due to the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies and the cam is Therefore, the distance away from the head does not change, and the grinding efficiency of the cam can be improved and the grinding efficiency can be improved.

  FIG. 9 is a view showing the inclined groove 88 of the second form provided in the grindstone 10 corresponding to FIG. 4, and the same constituent members are assigned the same reference numerals and detailed description thereof is omitted. On the inner peripheral surface 18 of the grindstone tip 11 of the grindstone 10, a plurality of inclined grooves 88 that are inclined at a predetermined inclination angle α with respect to the circumferential direction of the grindstone reach from the bottom surface of the foundation layer 13 to the inside of the abrasive grain layer 12. 5 (the same h as the inclined groove 20 shown in FIG. 5) and penetrates both the side surfaces 21 and 22 of the foundation layer 13 and the abrasive grain layer 12 parallel to the circumferential direction of the grindstone to form the foundation layer 13 and the abrasive grain layer 12. It is engraved. The above points are the same as the inclined grooves 20 of the first embodiment shown in FIG. 4 and the like, but are different in the following points.

The inclined groove 88 is in the contact surface S between the outer peripheral surface of the abrasive grain layer 12 and the workpiece W, and the abrasive grain layer 12 is parallel to the grindstone axis at an arbitrary position on the circumference and has a grindstone diameter. A predetermined pitch so that the sum of the widths w1 and w2 of the inclined grooves 88 existing on the cutting line CL when cutting in the direction is always equal, that is, the width w0 of one inclined groove 88 = w1 + w2. It is engraved at equal intervals in Pa. The width of the inclined groove 88 existing on the cutting line CL may be defined by replacing the area of the inclined groove 88 existing in the contact surface S.
That is, the inclined groove 88 has one edge 88a of one inclined groove 88 at the intersection xa between one edge Sa parallel to the grinding wheel circumferential direction of the contact surface S and one edge Sf parallel to the grinding wheel axial direction. Is located at the intersection xb between the other edge Sb parallel to the grindstone circumferential direction and one edge Sf parallel to the grindstone axial direction, one edge 88a of the inclined groove 88 adjacent to the one inclined groove 88. Is engraved so that is located.

  Here, the effect of reducing the dynamic pressure generated in the grinding fluid by the inclined groove 88 is proportional to the width w0 (= w1 + w2) of the inclined groove 88. Therefore, as described above, the outer peripheral surface of the abrasive layer 12 is formed by engraving the inclined groove 88 so that the width w0 (= w1 + w2) of the inclined groove 88 is constant over the entire outer periphery of the abrasive layer 12. The dynamic pressure reduction effect can be made constant over the entire circumference. As a result, uniform grinding can be performed on the workpiece W. Further, the grinding fluid supplied from above to the contact surface S flows out from above and below through the inclined groove 88 penetrating the contact surface S, and is generated between the outer peripheral surface of the abrasive grain layer 12 and the workpiece W. The dynamic pressure of the grinding fluid can be released. As a result, the workpiece W is displaced in the direction away from the grindstone 10 by the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies to change the distance at which the workpiece W is separated from the grindstone 10. Thus, the grinding accuracy of the ground workpiece W can be increased.

  FIG. 10 is a view showing the inclined grooves 88 and 89 of the third embodiment provided in the grindstone 10 in correspondence with FIG. 9, and the same constituent members are assigned the same reference numerals and detailed description thereof is omitted. The inner peripheral surface 18 of the grindstone tip 11 of the grindstone 10 has a similar inclined groove 89 in the central portion between one inclined groove 88 and the adjacent inclined groove 88 shown in FIG. A plurality of inclined grooves 89 inclined by an inclination angle α are parallel to the circumferential direction of the grindstone at a depth from the bottom surface of the base layer 13 to the inside of the abrasive grain layer 12 (the same h as the inclined groove 86 shown in FIG. 5). The base layer 13 and the abrasive layer 12 are cut into the base layer 13 and the abrasive layer 12 through both side surfaces 21 and 22 of the abrasive layer 12. That is, the inclined groove 88 and the adjacent inclined groove 89 are engraved at equal intervals with a pitch Pa / 2.

  By adding this inclined groove 89, the inner peripheral surface 18 of the grindstone tip 11 of the grindstone 10 is within the contact surface S between the outer peripheral surface of the abrasive grain layer 12 and the workpiece W, and the abrasive grain layer 12 is provided. The sum of the width w0 of the inclined groove 88 and the widths w1 and w2 of the inclined groove 89 existing on the cutting line CL when cut in an arbitrary position on the circumference in parallel with the grindstone axis and in the direction of the grindstone diameter. Are always equal, that is, so as to be the sum of the width w0 of one inclined groove 88 and the width w0 of one inclined groove 89. Note that the widths of the inclined grooves 88 and the inclined grooves 89 existing on the cutting line CL may be defined in place of the areas of the inclined grooves 88 and the inclined grooves 89 existing in the contact surface S.

  In this way, the inclined grooves 88 and 89 are engraved so that the widths 2w0 (= w0 + w1 + w2) of the inclined grooves 88 and 89 are constant over the entire circumference of the outer peripheral surface of the abrasive layer 12. The dynamic pressure reduction effect can be made constant over the entire surface. As a result, uniform grinding can be performed on the workpiece W. Furthermore, since the grinding fluid supplied to the contact surface S from above flows out from above and below through the inclined groove 88 and the inclined groove 89 penetrating the contact surface S, the outflow amount can be increased, and the abrasive layer 12 The dynamic pressure of the grinding fluid generated between the outer peripheral surface of the workpiece and the workpiece W can be released more efficiently. As a result, the workpiece W is displaced in the direction away from the grindstone 10 by the dynamic pressure of the grinding fluid, or the dynamic pressure generated in the grinding fluid varies to change the distance at which the workpiece W is separated from the grindstone 10. Thus, the grinding accuracy of the ground workpiece W can be increased. The width of the added inclined groove 89 may be changed from the original width of the inclined groove 88. Two or more inclined grooves 89 may be added. In this case, the inclined grooves 89 to be added are engraved with the same width, the same inclination angle, and the same pitch so as to achieve the above-described effect. In the examples of FIGS. 9 and 10, the relationship of L <V described in the example of FIG. 4 may not be satisfied. That is, it is only necessary that the total groove width is uniform.

  In the inclined grooves 20, 88, 89 shown in FIGS. 4, 9, and 10, the inclined grooves 88, 89 shown in FIG. 9 or FIG. 10 have a constant dynamic pressure reduction effect over the entire outer peripheral surface of the abrasive grain layer 12. As a result, the workpiece W can be ground without unevenness, and the dynamic pressure of the grinding fluid generated between the outer peripheral surface of the abrasive grain layer 12 and the workpiece W can be efficiently released to grind the workpiece. This is most preferable because the grinding accuracy of W can be increased. Next, the inclined groove 20 shown in FIG. 4 efficiently releases the dynamic pressure of the grinding fluid generated between the outer peripheral surface of the abrasive grain layer 12 and the workpiece W. This is preferable because the grinding accuracy of the ground workpiece W can be increased. However, it is not limited to the inclined grooves 20, 88, 89 of these shapes, and even if the inclined grooves are simply formed on the inner peripheral surface 18 of the grindstone chip 11 of the grindstone 10, The dynamic pressure of the grinding fluid generated between the outer peripheral surface and the workpiece W can be efficiently released, and the grinding accuracy of the ground workpiece W can be increased.

  In the grindstone 10 of the above-described embodiment, a plurality of inclined grooves 20 having a constant groove width (groove area) are provided, but as shown in FIG. 11 (the same constituent members as those in FIG. A plurality of inclined grooves 28 of the fourth form in which the groove width (groove area) gradually decreases from the inner peripheral surface side to the outer peripheral surface side, for example, the inclined grooves 28 having a V-shaped cross section in the radial direction of the grindstone 10 are provided. You may do it. According to such a configuration, the groove width (groove area) can be increased as the abrasive grain layer 12 becomes thinner. Therefore, when the pores are gradually clogged and the dynamic pressure generated in the grinding fluid starts to rise, the dynamic pressure can be released by the inclined grooves 28 having the minimum groove width (groove area), so that high accuracy is achieved. Grinding can be performed. And since the abrasive grain volume (the number of abrasive grains) acting on the grinding process is gradually reduced, the life of the grinding wheel can be prolonged. Note that the groove is not limited to a V-shaped cross section as long as the groove width (groove area) is gradually reduced, and may be, for example, a semicircular cross section.

  Further, in the grindstone 10 of the above-described embodiment, a plurality of inclined grooves 20 having a constant groove depth from the inner peripheral surface side of the grindstone chip 11 are provided, but FIG. 12 (the same constituent members as those in FIG. ), The groove depths are different (a> b> c) A plurality of the inclined grooves 25, 26, 27 of the fifth embodiment may be provided respectively. According to such a configuration, as the abrasive layer 12 wears and the thickness of the abrasive layer 12 decreases, the inclined groove 25 having the deepest groove depth, the inclined groove 26 having the next groove depth, and the next It can be made to appear sequentially in the inclined groove 27 of the groove depth. Therefore, when the pores are gradually clogged and the dynamic pressure generated in the grinding fluid starts to rise, the dynamic pressure can be released by the minimum number of inclined grooves 25, 26, and 27. Grinding can be performed. And since the abrasive grain volume (the number of abrasive grains) acting on the grinding process is gradually reduced, the life of the grinding wheel can be prolonged. Note that the present invention is not limited to the inclined grooves having three different groove depths, and any number of inclined grooves having different groove depths may be engraved.

  In the above embodiment, the width of the workpiece W is smaller than the width of the grindstone 10, and the specifications of the inclined groove 20 are obtained assuming that the axial length of the contact surface S is equal to the width A of the workpiece W. However, when the width of the workpiece W is larger than the width A of the grindstone 10, the specifications of the inclined groove 20 are obtained assuming that the axial length of the contact surface S is equal to the width of the grindstone.

  Moreover, in the said embodiment, the grindstone circumferential direction length L of the contact surface S is approximated by the length of the line segment which connects the intersection where the outer periphery circle of the grindstone 10 and the outer periphery circle of the workpiece W cross | intersect. However, when the workpiece W is rotationally driven with the grinding wheel 10 being cut into the workpiece W by the cutting amount t, the actual circumferential length of the contact surface S is shown in FIG. As described above, since Ls is strictly determined by cutting the grindstone 10 into the workpiece W, the length of the contact surface S in the circumferential direction of the grindstone may be Ls <L = A / tan α−P.

1 is an overall view of a grindstone composed of segment-type grindstone chips showing an embodiment of the present invention. It is a figure which shows a grindstone chip. It is a figure which shows the state which grinds a workpiece with the grinder equipped with the grindstone with an inclined groove | channel. It is the figure which expanded and showed the grinding surface of the grindstone. It is a figure which shows the state by which the inclined groove | channel of the 1st form was engraved in the abrasive grain layer. It is a figure which shows the relationship between the overlap amount of a grinding groove, inclination-angle (alpha), the circumferential direction pitch P, and the axial direction length A of the contact surface. It is a figure which shows the circumferential direction length of a contact surface. It is a figure which shows the contact surface of a grindstone and the side part of a cam. It is a figure which shows the state by which the inclined groove | channel of the 2nd form was engraved in the abrasive grain layer. It is a figure which shows the state by which the inclined groove | channel of the 3rd form was engraved in the abrasive grain layer. It is a figure which shows the state by which the inclined groove | channel of the 4th form which groove | channel width (groove area) reduces gradually on an abrasive grain layer was engraved. It is a figure which shows the state by which the inclination groove | channel of the 5th form from which a groove depth differs was engraved in the abrasive grain layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Whetstone, 11 ... Whetstone tip, 12 ... Abrasive grain layer, 13 ... Underlayer, 14 ... Core, 15 ... Grinding surface, 16 ... Superabrasive grain, 17 ... Vitrified bond, 18 ... Inner peripheral surface, 20, 25, 26, 27, 28, 88, 89 ... Inclined groove, 21, 22 ... Side, 23, 24 ... Extension line, DESCRIPTION OF SYMBOLS 30 ... Grinding machine, 31 ... Grinding wheel base, 32 ... Grinding wheel axis, 33 ... Workpiece support device, 35 ... Coolant nozzle, S ... Contact surface, W ... Workpiece , Wl: lift part, α: inclination angle, L: circumferential length, P: circumferential pitch (interval).

Claims (4)

In the grindstone for grinding the workpiece while supplying a grinding liquid toward the contact surface between the outer circumferential surface of the grindstone layer and the workpiece, a grindstone layer is formed on the outer periphery,
The inner circumferential surface of the grinding wheel layer is inclined at a predetermined angle with respect to the grinding wheel circumferential direction , and a plurality of inclined grooves are engraved at equal intervals.
When the intersection of the inclined groove and the extension line of one edge parallel to the grinding wheel circumferential direction of the contact surface is defined as one intersection point and the intersection point of the other edge extension line is defined as the other intersection point, The other intersection and the one intersection of one inclined groove and the adjacent inclined groove overlap by a predetermined overlap amount in the grinding wheel circumferential direction ,
When the inclined grooves appear on the outer peripheral surface of the grindstone layer due to wear of the grindstone layer, the grindstone circumferential length of the contact surface is smaller than the overlap amount of the grindstone with respect to the workpiece. A grindstone characterized in that at least one of a cutting depth and an inclination angle or interval of the inclined groove is set . The grindstone according to claim 1 , wherein the grindstone layer is in a contact surface between the outer peripheral surface of the grindstone layer and the workpiece, and the grindstone layer is parallel to the grindstone axis at an arbitrary position on the circumference and the grindstone diameter. A whetstone characterized in that the sum of the widths of the inclined grooves existing on the cutting line when cutting in the direction of is always equal. The grindstone according to claim 1 or 2 , wherein an inclined groove whose groove width is gradually reduced from the inner peripheral surface side to the outer peripheral surface side of the grindstone layer is formed. The grindstone according to claim 1 or 2 , wherein a plurality of inclined grooves having different groove depths from the inner peripheral surface side of the grindstone layer are formed.

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