Grinding method and grinding wheel

Abstract

To enable grinding liquid to be sufficiently supplied to a ground portion of a work-piece, while securing rigidity of a grindstone shaft by shortening the grindstone shaft, in grinding an inner diameter of the work-piece.SOLUTION: A grindstone with a shaft (10) comprises a base metal (11), a grindstone shaft (12) whose one end is supported on the base metal (11), and a grindstone (13) mounted on the grindstone shaft (12). Guide shapes (15a, 17, 18 and 18a) are formed on the base metal (11) so that grinding liquid discharged toward an outer peripheral surface of the base metal (11) can be supplied to a ground portion of a work-piece (1) while flowing in different directions.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a grinding method and a mounted wheel. [Background technology]

[0002] Conventionally, in the internal grinding of a workpiece, a grindstone with a shaft has been used, in which a grindstone is attached to a grindstone shaft that is rotated by a wheel head (see Patent Document 1).

[0003] In internal grinding, the grinding load is applied to the grinding wheel, which causes the grinding wheel spindle to bend. This bending is significant compared to the processing accuracy required for grinding, so for high-precision internal grinding, it is necessary to perform a spark-out, which stops the axial movement of the grinding wheel spindle for several seconds until the bending disappears. If the machining hole is long and narrow, the grinding wheel spindle to be used must also be long and narrow. In that case, the rigidity of the grinding wheel spindle decreases, and it takes time to spark-out to recover the bending of the grinding wheel spindle, which increases the processing time.

[0004] In addition, in internal grinding, it is necessary to supply the grinding fluid to the grinding point of the workpiece. When machining a small diameter long and narrow hole, it is necessary to arrange the grinding fluid nozzle so that the grinding fluid can easily enter the gap between the grinding wheel spindle and the machined hole. If the machined hole is a blind hole, it is necessary to supply the grinding fluid to the grinding point of the workpiece from the same side as the grinding wheel spindle. Patent Document 1 discloses bending the grinding fluid supply pipe to follow the axial direction of the grinding wheel spindle and arranging the grinding fluid nozzle toward the machined hole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-69303 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, if you try to shorten the grinding wheel shaft to ensure its rigidity in order to shorten the time required for spark out and reduce the processing time, the distance between the workpiece and the wheel head becomes too short when grinding the deepest part of the machining hole, making it difficult to properly position the injection port of the grinding fluid. If the grinding fluid cannot be supplied sufficiently to the grinding point, problems such as grinding burn, where the temperature of the grinding point reaches 500°C or more, or shortening the life of the grinding wheel will occur.

[0007] An object of the present disclosure is to provide a grinding method and a grinding wheel that can shorten the grinding wheel shaft to ensure the rigidity of the grinding wheel shaft while supplying a sufficient amount of grinding fluid to the grinding point of the workpiece. [Means for solving the problem]

[0008] The first aspect is a grinding method for rotating a grinding wheel (13) attached to a grinding wheel spindle (12) protruding from a base metal (11) to grind the internal diameter of a workpiece (1), in which the distance between the base metal (11) and the workpiece (1) changes during grinding, and the distance is 5 mm or less when grinding the innermost part of the workpiece (1), and grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding point of the workpiece (1) while changing its flow direction due to guide shapes (15a, 17, 18, 18a) provided on the base metal (11).

[0009] In the first embodiment, even if the grindstone shaft (12) is shortened so that the distance between the base metal (11) and the workpiece (1) during grinding is 5 mm or less, the guide shapes (15a, 17, 18, 18a) provided on the base metal (11) allow sufficient supply of grinding fluid to the grinding location of the workpiece (1). This makes it possible to suppress grinding burn and wear of the grindstone (13), thereby extending the life of the grindstone with shaft.

[0010] In the second embodiment, the inner diameter of the workpiece (1) is ground while the base metal (11) in the first embodiment is covered with a non-rotating umbrella-shaped member (21).

[0011] In the second aspect, the grinding fluid can be prevented from scattering from the outer peripheral surface of the base metal (11), thereby enhancing the effect of concentrating and supplying the grinding fluid to the portion of the workpiece (1) to be ground.

[0012] The third aspect is a shaft-mounted grinding wheel comprising a base metal (11), a grinding wheel spindle (12) having one end supported by the base metal (11), and a grinding wheel (13) attached to the grinding wheel spindle (12) and rotating together with the grinding wheel spindle (12) to grind the internal diameter of a workpiece (1), in which a guide shape (15a, 17, 18, 18a) is provided on the base metal (11) so that grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding point of the workpiece (1) while changing its flow direction.

[0013] In the third aspect, even if the grindstone spindle (12) is shortened so that the distance between the base metal (11) and the workpiece (1) during grinding is 5 mm or less, the guide shapes (15a, 17, 18, 18a) provided on the base metal (11) allow sufficient supply of grinding fluid to the grinding point of the workpiece (1). This makes it possible to suppress grinding burn and to suppress wear of the grindstone (13), thereby extending the life of the shaft-mounted grindstone. In addition, since the grindstone spindle (12) can be shortened, it is possible to suppress a decrease in processing accuracy caused by bending of the grindstone spindle (12), and it is possible to shorten the time required for spark out, thereby shortening the processing time, i.e., improving the processing speed.

[0014] In a fourth aspect, in the third aspect, the base metal (11) has a truncated cone portion (15) having the grindstone spindle (12) at its top, and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15). A concave surface (15a) is provided on the outer peripheral surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a). At the top of the truncated cone portion (15), an inclination angle θ of the concave surface (15a) with respect to the grindstone spindle (12) is greater than or equal to 0° and less than or equal to 20°, and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15). At the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer peripheral surface of the cylindrical portion (16) at an angle φ of greater than or equal to 40° and less than or equal to 90°.

[0015] In the fourth embodiment, the injection pressure of the grinding fluid can be used to make the grinding fluid discharged toward the outer circumferential surface of the truncated cone portion 15 of the base metal 11 flow along the concave surface 15a. This allows the grinding fluid to be supplied from the top of the truncated cone portion 15 along the grindstone shaft 12 toward the grinding point of the workpiece 1.

[0016] In the fifth aspect, in the third aspect, the base metal (11) has a truncated cone portion (15) having the grinding wheel shaft (12) at its top, and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15), and a plurality of twisted blades (17) are provided on the outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a).

[0017] In the fifth aspect, by rotating a plurality of blades (17) together with the base metal (11), the grinding fluid discharged toward the outer peripheral surface of the base metal (11) can be made to flow along the outer peripheral surface of the base metal (11) toward the grinding wheel shaft (12) against centrifugal force, so that the grinding fluid can be supplied from the top of the truncated cone portion (15) along the grinding wheel shaft (12) toward the grinding point of the workpiece (1).

[0018] In a sixth aspect, in the fifth aspect, a concave surface (15a) is further provided as the guide shape (15a, 17, 18, 18a) on the outer peripheral surface of the truncated cone portion (15) between the multiple blades (17), and the inclination angle θ of the concave surface (15a) with respect to the grinding wheel shaft (12) at the apex of the truncated cone portion (15) is not less than 0° and not more than 20°, and the inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer peripheral surface of the cylindrical portion (16) at an angle φ of not less than 40° and not more than 90°.

[0019] In the sixth aspect, in addition to the effects of the fifth aspect, the effects of the fourth aspect can be obtained.

[0020] In a seventh aspect, in the fifth or sixth aspect, a cover member (19) is provided on the truncated cone portion (15) so as to cover the plurality of blades (17).

[0021] In the seventh aspect, the grinding fluid can be prevented from scattering from the outer peripheral surface of the truncated cone portion (15), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1).

[0022] In the eighth aspect, in the third aspect, the base metal (11) has a truncated cone portion (15) having the grinding wheel shaft (12) at its top, and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15), and a plurality of twisted grooves (18) are provided on the outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a).

[0023] In the eighth aspect, by rotating the multiple grooves (18) together with the base metal (11), the grinding fluid discharged toward the outer peripheral surface of the base metal (11) can be made to flow along the multiple grooves (18) toward the grinding wheel shaft (12) against centrifugal force, so that the grinding fluid can be supplied from the top of the conical truncated portion (15) along the grinding wheel shaft (12) toward the grinding point of the workpiece (1).

[0024] In a ninth aspect, in the eighth aspect, a concave surface (18a) is further provided on a bottom surface of the multiple grooves (18) as the guide shape (15a, 17, 18, 18a), and an inclination angle θ of the concave surface (18a) with respect to the grinding wheel spindle (12) at the apex of the truncated cone portion (15) is not less than 0° and not more than 20°, the inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), and the concave surface (18a) at the bottom of the truncated cone portion (15) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of not less than 40° and not more than 90°.

[0025] In the ninth aspect, the injection pressure of the grinding fluid can be utilized to make the grinding fluid released toward the outer peripheral surface of the truncated cone portion (15) of the base metal (11) flow along the bottom surface, i.e., the concave surface (18a), of the groove (18) in the truncated cone portion (15), thereby making it possible to more efficiently supply the grinding fluid to the grinding point of the workpiece (1).

[0026] In a tenth aspect, in the eighth or ninth aspect, a cover member (19) is provided on the truncated cone portion (15) so as to cover the plurality of grooves (18).

[0027] In the tenth aspect, the grinding fluid can be prevented from scattering from the outer peripheral surface of the truncated cone portion (15), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1). [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a perspective view of a grinding device equipped with a mounted grindstone according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a grinding device equipped with a mounted grindstone according to an embodiment. [Diagram 3] FIG. 3 is a perspective view of the mounted grindstone according to the embodiment. [Figure 4] FIG. 4 is a side view of the mounted grindstone according to the embodiment (as viewed from a direction perpendicular to the grindstone axis). [Diagram 5] FIG. 5 is a perspective view of a mounted grindstone according to the first modified example. [Figure 6] FIG. 6 is a perspective view of a mounted grindstone according to the second modification. [Figure 7] FIG. 6 is a perspective view of a mounted grindstone according to the third modification. [Figure 8] FIG. 8 is a side view (viewed from a direction perpendicular to the grindstone axis) of a grinding device equipped with a grindstone mounted on a shaft according to Modification 4. In FIG. [Figure 9] FIG. 9 is a cross-sectional view of a grinding device equipped with a mounted grindstone according to Comparative Example 1. As shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view of a grinding device equipped with a mounted grindstone according to Comparative Example 2. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] (Embodiment) Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical idea of ​​the present disclosure. Since each drawing is intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding. The specific numerical values ​​of various parameters described in the following embodiments are merely examples and are not limited thereto.

[0030] <Configuration of a mounted grindstone> As shown in Figures 1 to 4, the grinding device (100) mainly comprises a shaft-mounted grindstone (10) for performing internal grinding of a workpiece (1), a wheel head (20) for rotating the shaft-mounted grindstone (10), and a grinding fluid supply unit (30) for supplying grinding fluid to the grinding point of the workpiece (1).

[0031] The grinding wheel (10) includes a metal base (11), an elongated grinding wheel shaft (12) with one end supported by the base (11), and a grinding wheel (13) replaceably attached to the grinding wheel shaft (12). The base (11) has, for example, a conical truncated portion (15) with the grinding wheel shaft (12) at its top, and a cylindrical portion (16) connected to the bottom of the conical truncated portion (15). The cylindrical portion (16) may be chamfered for a wrench so as to be attached to the wheel head (20). The grinding wheel shaft (12) may be integrally molded from the same material as the base (11). If it is desired to increase the rigidity of the grinding wheel shaft (12), the grinding wheel shaft (12) made of a super-hard material may be inserted and joined to the base (11). The grindstone 13 may have, for example, a cylindrical shape and be fixed to the grindstone spindle 12 with the grindstone spindle 12 inserted into a cylindrical hole in the grindstone 13. The grindstone 13 rotates together with the grindstone spindle 12 to grind the inner diameter of the workpiece 1. The diameter of the grindstone 13 is several mm smaller than the diameter of the hole to be formed in the workpiece 1.

[0032] The base metal (11) of the mounted grinding wheel (10) has a fixing member (14) on the opposite side to the grinding wheel shank (12) for mounting the mounted grinding wheel (10) to a rotation mechanism (not shown) of a wheel head (20). The fixing member (14) may be, for example, a mounting screw or a pull-in taper (fastener). The wheel head (20) is configured so that the mounted grinding wheel (10) can be advanced and retreated in the axial direction of the grinding wheel shank (12).

[0033] The grinding fluid ejection port (31) of the grinding fluid supply unit (30) is arranged so as to be able to eject the grinding fluid onto the outer peripheral surface of the base metal (11) of the shaft-mounted grinding wheel (10), specifically onto the outer peripheral surface of the truncated cone portion (15). The grinding fluid supply unit (30) may supply the grinding fluid from the grinding fluid ejection port (31) in a direction perpendicular to the grinding wheel shaft (12), or may supply the grinding fluid in a direction inclined toward the grinding wheel (13) from the perpendicular direction. The piping to the grinding fluid ejection port (31) in the grinding fluid supply unit (30) may be arranged along the outer wall (non-rotating portion) of the wheel head (20).

[0034] In the grinding device 100, the grindstone 13 may be rotated at a high speed and the workpiece 1 may be rotated at a low speed. In this case, the workpiece 1 may be held on a rotatable worktable. Instead of or in addition to the configuration in which the mounted grindstone 10 is advanced or retreated together with the wheel head 20 in the axial direction of the grindstone spindle 12, the workpiece 1 may be advanced or retreated together with the worktable that holds the workpiece 1 in the axial direction of the grindstone spindle 12.

[0035] <Guide shape> In internal grinding of the workpiece (1), a grindstone (13) is inserted into a recess (machined hole) provided in the workpiece (1) and rotated to grind the inner surface of the machined hole. The grindstone (13) inserted into the machined hole of the workpiece (1) is movable in the axial direction of the grindstone shaft (12) and also in the radial direction of the grindstone shaft (12). This allows the inner surface of the machined hole to be machined into a desired shape.

[0036] In the grinding method of this embodiment, when grinding the inner diameter of the workpiece (1), the grindstone (13) is moved in the axial direction of the grindstone shaft (12), so that the distance between the base metal (11) and the workpiece (1) (the end face of the workpiece (1) on the base metal (11) side) changes. In this embodiment, a shaft-mounted grindstone (10) with a short grindstone shaft (12) is used so that the distance between the base metal (11) and the workpiece (1) is 5 mm or less when grinding the innermost part of the processed hole of the workpiece (1) with the grindstone (13) while avoiding contact between the base metal (11) and the workpiece (1). Therefore, the grinding fluid is supplied to the grinding part of the workpiece (1) while changing the flow direction of the grinding fluid discharged toward the outer peripheral surface of the base metal (11) by the guide shapes (15a, 17, 18, 18a) provided on the base metal (11). In other words, the guide shapes (15a, 17, 18, 18a) are provided on the base metal (11) so that the grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding part of the workpiece (1) while changing its flow direction. The guide shapes (15a, 17, 18, 18a) supply the grinding fluid sprayed onto the outer peripheral surface of the base metal (11) to the grinding wheel spindle (12) and grinding wheel (13) located on the inner diameter side against the centrifugal force while ensuring the maximum rigidity of the grinding wheel spindle (12) and base metal (11). The guide shapes (15a, 17, 18, 18a) change the flow direction of the grinding fluid on the outer peripheral surface of the base metal (11) from the spray direction of the grinding fluid from the grinding fluid spray port (31) to the direction of the grinding part of the workpiece (1).

[0037] Specifically, as shown in Fig. 4, a concave surface (15a) may be provided as a guide shape (15a, 17, 18, 18a) on the outer circumferential surface of the truncated cone portion (15) of the base metal (11). The inclination angle θ of the concave surface (15a) with respect to the grindstone shaft (12) (the central axis J of the grindstone shaft (12)) is 0° or more and 20° or less at the top of the truncated cone portion (15), and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. The angle φ is equal to the inclination angle of the concave surface (15a) with respect to the central axis J of the grindstone shaft (12) at the bottom of the truncated cone portion (15).

[0038] The shape of the base metal (11) is a combination of a truncated cone portion (15) having an outer circumferential surface at an inclination angle of, for example, 45° with respect to the bottom surface, and a cylindrical portion (16) into which a fixing member (14) for a wheel head (20) is inserted, but in the example shown in Fig. 4, the outer circumferential surface of the truncated cone portion (15) is replaced with a curved concave surface (15a). As shown in Fig. 4, when the mounted grindstone (10) is viewed from a direction perpendicular to the grindstone shaft (12), a curve (for example, a parabola or a circular arc) that is a concave surface (15a) with an inclination angle θ of about 0 to 20° with respect to the grindstone shaft (12) starts to extend from the top of the truncated cone portion (15) that has a diameter slightly (for example, about 1 to 2 mm) larger than the diameter of the grindstone (13), and the inclination angle θ changes significantly toward the bottom of the truncated cone portion (15). The curved line is connected to the outer circumferential surface of a cylindrical portion (16) having a diameter larger than that of the grindstone (13) at an angle φ of 40° or more and 90° or less.

[0039] In the shape of the base metal (11) shown in FIG. 4, the rigidity of the base metal (11) is slightly reduced compared to when the outer peripheral surface of the truncated cone portion (15) is not made into a concave surface (15a). However, compared to the effect of improving rigidity by shortening the grinding wheel spindle (11), the reduction in rigidity of the base metal (11) is small enough to not be a problem.

[0040] On the other hand, in the shape of the base metal (11) shown in Fig. 4, the inclination angle θ of the concave surface (15a) provided on the outer peripheral surface of the truncated cone portion (15) with respect to the grindstone shaft (12) increases from the top to the bottom of the truncated cone portion (15), so that the grinding fluid discharged toward the outer peripheral surface of the truncated cone portion (15) of the base metal (11) can be made to flow along the concave surface (15a) by utilizing the injection pressure of the grinding fluid. Also, since the inclination angle θ of the concave surface (15a) with respect to the grindstone shaft (12) at the top of the truncated cone portion (15) is gentle, ranging from 0° to 20°, the grinding fluid can be supplied from the top of the truncated cone portion (15) along the grindstone shaft (12) toward the grinding point of the workpiece (1).

[0041] In addition, in the shape of the base metal (11) shown in Fig. 4, the inclination angle θ of the concave surface (15a) with respect to the grindstone shaft (12) increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer peripheral surface of the cylindrical portion (16) at an angle φ of 40° to 90°. Therefore, even when the grinding fluid is discharged toward the outer peripheral surface of the truncated cone portion (15) in a direction perpendicular or substantially perpendicular to the grindstone shaft (12) (the central axis J of the grindstone shaft (12)), specifically toward the outer peripheral surface near the bottom of the truncated cone portion (15), the grinding fluid is less likely to bounce back from the outer peripheral surface of the base metal (11). This improves the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1). This effect increases as the difference between the inclination angle θ of the concave surface (15) of the truncated cone portion (15) at the location where the grinding fluid from the grinding fluid ejection port (31) directly hits and the spray angle of the grinding fluid from the grinding fluid ejection port (31) (angle with respect to the grindstone shaft (12)) becomes smaller. Therefore, if the spray angle of the grinding fluid is 90° or close to 90°, the inclination angle θ of the concave surface (15) of the truncated cone portion (15) at the location where the grinding fluid from the grinding fluid ejection port (31) directly hits may be 70° or more and 90° or less.

[0042] <Modifications of the guide shape> [Variation 1] As shown in the first modified example in Fig. 5, a plurality of twisted blades (17) may be provided as guide shapes (15a, 17, 18, 18a) on the outer circumferential surface of the truncated cone portion (15) of the base metal (11). The blades (17) extend from the top to the bottom of the truncated cone portion (15) so as to be twisted in the rotation direction of the shaft-mounted grindstone (10), i.e., the base metal (11). By rotating the blades (17) together with the base metal (11), the grinding fluid discharged toward the outer circumferential surface of the base metal (11) can flow toward the grindstone shaft (12) against the centrifugal force along the outer circumferential surface of the base metal (11) between the blades (17). Therefore, since the grinding fluid can be released from the top of the truncated cone portion (15) in a direction along the grinding wheel shaft (12), the grinding fluid can be supplied to the grinding wheel (13), i.e., the grinding point of the workpiece (1), through the gap between the machining hole in the workpiece (1) and the grinding wheel shaft (12).

[0043] In addition, in the first modification shown in Fig. 5, a concave surface (15a) may be further provided as a guide shape (15a, 17, 18, 18a) on the outer peripheral surface of the truncated cone portion (15) between the plurality of blades (17). The inclination angle θ of the concave surface (15a) with respect to the grindstone shaft (12) (central axis J) is 0° or more and 20° or less at the top of the truncated cone portion (15), and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer peripheral surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. In this way, in addition to the above-mentioned effects, the same effects as those in the embodiment shown in Fig. 4 can be obtained.

[0044] 5, the outer circumferential surface of the truncated cone portion 15 of the base metal 11 may be provided with a plurality of blades 17 without providing a concave surface 15a. In this case, the above-mentioned effect can be obtained. The plurality of blades 17 may be provided only in a portion of the area between the top and bottom of the truncated cone portion 15, for example, in the vicinity of the top.

[0045] [Variation 2] As shown in the second modification in FIG. 6, a plurality of twisted grooves 18 may be provided as guide shapes 15a, 17, 18, 18a on the outer circumferential surface of the truncated cone portion 15 of the base metal 11. The grooves 18 extend from the top to the bottom of the truncated cone portion 15 so as to be twisted in the rotation direction of the shafted grindstone 10, i.e., the base metal 11. By rotating the grooves 18 together with the base metal 11, the grinding fluid discharged toward the outer circumferential surface of the base metal 11 can flow toward the grindstone shaft 12 along the grooves 18 against the centrifugal force. Therefore, the grinding fluid can be discharged from the top of the truncated cone portion 15 in the direction along the grindstone shaft 12, so that the grinding fluid can be supplied to the grindstone 13, i.e., the grinding point of the workpiece 1, through the gap between the machining hole of the workpiece 1 and the grindstone shaft 12. The configuration of the second modification shown in FIG. 6 corresponds to the configuration of the first modification shown in FIG. 5 in which the width (width in the direction of rotation) of the blades (17) is increased.

[0046] In addition, in the second modification shown in FIG. 6, a concave surface (18a) may be further provided as a guide shape (15a, 17, 18, 18a) on the bottom surface of the plurality of grooves (18). The inclination angle θ of the concave surface (18a) with respect to the grindstone spindle (12) (central axis J) is 0° or more and 20° or less at the top of the truncated cone portion (15), and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (18a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. In other words, the concave surface (18a), which is the bottom surface of the plurality of grooves (18), has a curved shape similar to the concave surface (15a) provided on the outer circumferential surface of the truncated cone portion (15) in the embodiment shown in FIG. 4. In this way, for the same reason as in the embodiment shown in Fig. 4, the grinding fluid discharged toward the outer circumferential surface of the base metal (11) can be made to flow easily along the grooves (18) of the truncated cone portion (15), thereby achieving the aforementioned effect more significantly. In this case, if the outer circumferential surface of the truncated cone portion (15) between the grooves (18) is also formed into a curved shape similar to the concave surface (15a) provided on the outer circumferential surface of the truncated cone portion (15) in the embodiment shown in Fig. 4, scattering of the grinding fluid can be further suppressed, thereby achieving the aforementioned effect more significantly.

[0047] In the second modification shown in Fig. 6, the bottom surfaces of the grooves 18 do not necessarily need to have the concave surface 18a. Even in this case, the above-mentioned effect can be obtained. The grooves 18 may be provided only in a part of the area between the top and bottom of the truncated cone portion 15, for example, in the vicinity of the top.

[0048] [Variation 3] The third modification shown in FIG. 7 differs from the first modification shown in FIG. 5 in that a cover member 19 is provided on the truncated cone portion 15 so as to cover the blades 17. The cover member 19 may be joined to the blades 17 by brazing. The cover member 19 may be provided so as to cover a portion of each of the blades 17. When the cover member 19 is provided, the grinding fluid is supplied to the outer circumferential surface of the truncated cone portion 15 through a gap between the cover member 19 and the cylindrical portion 16. This can prevent the grinding fluid from scattering from the outer circumferential surface of the truncated cone portion 15, thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece 1.

[0049] 6, a cover member similar to the cover member (19) of Modification 3 may be provided on the truncated cone portion (15) so as to cover the grooves (18). This provides the same effects as those of Modification 3.

[0050] [Variation 4] The fourth modification shown in Fig. 8 differs from the third modification shown in Fig. 7 in that, instead of the cover member (19) provided on the truncated cone portion (15), a non-rotating umbrella-shaped member (21) attached via an arm to the outer wall (non-rotating portion) of the wheel head (20) covers the outer circumferential surface of the base metal (11) (particularly the truncated cone portion (15)). When the umbrella-shaped member (21) is provided, the grinding fluid is supplied to the outer circumferential surface of the truncated cone portion (15) through the gap between the umbrella-shaped member (21) and the wheel head (20). This makes it possible to prevent the grinding fluid from scattering from the truncated cone portion (15), i.e., the outer circumferential surface of the base metal (11), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1).

[0051] In addition, in the variant example 4 shown in Figure 8, an umbrella-shaped member (21) is provided to cover the outer peripheral surface of the base metal (11) of variant example 1 shown in Figure 5, but similarly, an umbrella-shaped member (21) may be provided to cover the outer peripheral surface of the base metal (11) of the embodiment shown in Figure 4 or the outer peripheral surface of the base metal (11) of variant example 2 shown in Figure 6.

[0052] <Features of the embodiment (including modified examples)> The grinding method of the embodiment is a grinding method for grinding the inner diameter of a workpiece (1) by rotating a grindstone (13) attached to a grindstone spindle (12) protruding from a base metal (11). The distance between the base metal (11) and the workpiece (1) during grinding changes, and the distance is 5 mm or less when grinding the innermost part of the workpiece (1). The grinding fluid discharged toward the outer circumferential surface of the base metal (11) is supplied to the grinding part of the workpiece (1) while changing the flow direction due to guide shapes (15a, 17, 18, 18a) provided on the base metal (11).

[0053] In the grinding method of the embodiment, even if the grindstone spindle (12) is shortened so that the distance between the base metal (11) and the workpiece (1) during grinding is 5 mm or less, the guide shapes (15a, 17, 18, 18a) provided on the base metal (11) allow sufficient supply of grinding fluid to the grinding point of the workpiece (1). This makes it possible to suppress grinding burn and to suppress wear of the grindstone (13), thereby extending the life of the shaft-mounted grindstone (10). In addition, since the grindstone spindle (12) can be shortened, it is possible to suppress a decrease in processing accuracy caused by bending of the grindstone spindle (12), and to shorten the time required for spark out, thereby shortening the processing time, i.e., improving the processing speed.

[0054] In the grinding method of the embodiment, when the internal diameter grinding of the workpiece (1) is performed while the base metal (11) is covered with a non-rotating umbrella-shaped member (21), the grinding fluid can be prevented from scattering from the outer peripheral surface of the base metal (11), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1).

[0055] The shaft-mounted grinding wheel (10) of the embodiment includes a base metal (11), a grinding wheel shaft (12) having one end supported by the base metal (11), and a grinding wheel (13) attached to the grinding wheel shaft (12) and rotating together with the grinding wheel shaft (12) to grind the inner diameter of a workpiece (1). Guide shapes (15a, 17, 18, 18a) are provided on the base metal (11) so that grinding fluid discharged toward the outer circumferential surface of the base metal (11) is supplied to the grinding point of the workpiece (1) while changing its flow direction.

[0056] In the embodiment of the grindstone (10) with shaft, even if the grindstone shaft (12) is shortened so that the distance between the base metal (11) and the workpiece (1) during grinding is 5 mm or less, the guide shapes (15a, 17, 18, 18a) provided on the base metal (11) allow sufficient supply of grinding fluid to the grinding point of the workpiece (1). This makes it possible to suppress grinding burn and to suppress wear of the grindstone (13), thereby extending the life of the grindstone with shaft. In addition, since the grindstone shaft (12) can be shortened, it is possible to suppress a decrease in processing accuracy caused by bending of the grindstone shaft (12), and to shorten the time required for spark out, thereby shortening the processing time, i.e., improving the processing speed.

[0057] On the other hand, when the supply pipe of the grinding fluid is bent along the axial direction of the grinding wheel spindle as in the conventional case and the injection port of the grinding fluid is arranged toward the machining hole, if the grinding wheel spindle (12) is long as in Comparative Example 1 shown in FIG. 9, the grinding fluid injection port (31) can be arranged toward the machining hole, but if the grinding wheel spindle (12) is short as in Comparative Example 2 shown in FIG. 10, the grinding fluid injection port (31) cannot be arranged toward the machining hole. In Comparative Examples 1 and 2 shown in FIG. 9 and FIG. 10, the same elements as those in the embodiment shown in FIG. 2 are given the same reference numerals. As described above, it is desirable to make the grinding wheel spindle as short as possible to ensure rigidity, but if the distance between the base metal or wheel head of the grinding wheel spindle and the workpiece is about 5 mm or less, the base metal or wheel head blocks the machining hole of the workpiece as in Comparative Example 2 shown in FIG. 10, so that the injection port of the grinding fluid cannot be arranged appropriately. This can result in an insufficient supply of grinding fluid to the grinding point of the workpiece, causing problems such as grinding burn (where the temperature of the grinding point reaches 500°C or higher) and shortening the life of the grinding wheel.

[0058] In the embodiment of the mounted grindstone (10), the base metal (11) has a truncated cone portion (15) with a grindstone shaft (12) at its top, and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15), and a concave surface (15a) may be provided on the outer circumferential surface of the truncated cone portion (15) as a guide shape (15a, 17, 18, 18a). At the top of the truncated cone portion (15), the inclination angle θ of the concave surface (15a) with respect to the grindstone shaft (12) is 0° or more and 20° or less, and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. In this way, the grinding fluid discharged toward the outer circumferential surface of the truncated cone portion 15 of the base metal 11 can be made to flow along the outer circumferential surface of the truncated cone portion 15, i.e., the concave surface 15a. In addition, since the inclination of the concave surface 15a at the top of the truncated cone portion 15 relative to the grindstone shaft 12 is gentle, the grinding fluid can be supplied from the top of the truncated cone portion 15 along the grindstone shaft 12 toward the grinding point of the workpiece 1.

[0059] In the embodiment of the grindstone (10) with shaft, the base metal (11) has a truncated cone portion (15) with the grindstone shaft (12) at its top and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15). A plurality of twisted blades (17) may be provided on the outer circumferential surface of the truncated cone portion (15) as guide shapes (15a, 17, 18, 18a). In this way, by rotating the plurality of blades (17) together with the base metal (11), the grinding fluid discharged toward the outer circumferential surface of the base metal (11) can flow toward the grindstone shaft (12) along the outer circumferential surface of the base metal (11) against the centrifugal force. Therefore, the grinding fluid can be supplied from the top of the truncated cone portion (15) along the grindstone shaft (12) toward the grinding point of the workpiece (1). In this case, a concave surface (15a) may be further provided as a guide shape (15a, 17, 18, 18a) on the outer peripheral surface of the truncated cone portion (15) between the plurality of blades (17). The inclination angle θ of the concave surface (15a) at the top of the truncated cone portion (15) with respect to the grindstone shaft (12) is 0° or more and 20° or less, and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and the concave surface (15a) at the bottom of the truncated cone portion (15) is connected to the outer peripheral surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. In this way, the grinding fluid discharged toward the outer peripheral surface of the truncated cone portion (15) of the base metal (11) can be made to flow along the concave surface (15a) by utilizing the injection pressure of the grinding fluid, so that the grinding fluid can be more efficiently supplied to the grinding point of the workpiece (1). Furthermore, by providing a cover member (19) on the truncated cone portion (15) so as to cover the multiple blades (17), it is possible to prevent the grinding fluid from scattering from the outer peripheral surface of the truncated cone portion (15), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1).

[0060] In the embodiment of the mounted grindstone (10), the base metal (11) has a truncated cone portion (15) with the grindstone shaft (12) at its top and a cylindrical portion (16) connected to the bottom of the truncated cone portion (15), and a plurality of twisted grooves (18) may be provided on the outer circumferential surface of the truncated cone portion (15) as guide shapes (15a, 17, 18, 18a). In this way, by rotating the grooves (18) together with the base metal (11), the grinding fluid discharged toward the outer circumferential surface of the base metal (11) can flow toward the grindstone shaft (12) along the grooves (18) against the centrifugal force, so that the grinding fluid can be supplied from the top of the truncated cone portion (15) along the grindstone shaft (12) toward the grinding point of the workpiece (1). In this case, a concave surface (18a) may be further provided on the bottom surface of the plurality of grooves (18) as a guide shape (15a, 17, 18, 18a). At the top of the truncated cone portion (15), the inclination angle θ of the concave surface (18a) with respect to the grindstone shaft (12) is 0° or more and 20° or less, and the inclination angle θ increases from the top to the bottom of the truncated cone portion (15), and at the bottom of the truncated cone portion (15), the concave surface (18a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. In this way, the grinding fluid discharged toward the outer circumferential surface of the truncated cone portion (15) of the base metal (11) can be made to flow along the bottom surface of the groove (18), i.e., the concave surface (18a), by utilizing the injection pressure of the grinding fluid, so that the grinding fluid can be more efficiently supplied to the grinding point of the workpiece (1). Furthermore, by providing a cover member (19) on the truncated cone portion (15) so as to cover the multiple grooves (18), it is possible to prevent the grinding fluid from scattering from the outer peripheral surface of the truncated cone portion (15), thereby enhancing the effect of concentrating and supplying the grinding fluid to the grinding point of the workpiece (1).

[0061] (Other embodiments) In the above-described embodiment and modified examples, the concave surfaces (15a, 18a), the vanes (17), and the grooves (18) provided on the outer peripheral surface of the truncated cone portion (15) are exemplified as the guide shapes (15a, 17, 18, 18a). However, the present invention is not limited to these, and other guide shapes may be provided on the base metal (11) so that the grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding portion of the workpiece (1) while changing its flow direction.

[0062] Although the embodiment and modifications have been described above, it will be understood that various modifications of form and details are possible without departing from the spirit and scope of the claims. In addition, the above embodiment, modifications, and other embodiments may be combined or substituted as appropriate. [Industrial Applicability]

[0063] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for a grinding method and a mounted grinding wheel. [Explanation of symbols]

[0064] 1 Workpiece 10. Shafted Grindstone 11 base money 12 Grindstone spindle 13. Grindstone 15 Cone truncated part 15a Concave (guide shape) 16 Cylinder section 17 Blade (guide shape) 18 Groove (guide shape) 18a Concave (guide shape) 19 Lid member 21 Umbrella-shaped member

Claims

1. A grinding method for grinding an inner diameter of a workpiece (1) by rotating a grindstone (13) attached to a grindstone spindle (12) protruding from a base metal (11), comprising the steps of: The distance between the base metal (11) and the workpiece (1) during grinding changes, and the distance is 5 mm or less when the innermost portion of the workpiece (1) is ground. The grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding portion of the workpiece (1) while changing its flow direction due to guide shapes (15a, 17, 18, 18a) provided on the base metal (11); The base metal (11) is a truncated cone portion (15) having the grindstone shaft (12) mounted at its top; a cylindrical portion (16) connected to the bottom of the truncated cone portion (15); having a concave surface (15a), a plurality of twisted blades (17), or a plurality of twisted grooves (18) are provided on an outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a); an inclination angle θ of the concave surface (15a) at the apex of the truncated cone portion (15) with respect to the grindstone spindle (12) is equal to or greater than 0° and is equal to or smaller than 20°; The inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), At the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. Grinding method.

2. 2. The grinding method according to claim 1, The inner diameter of the workpiece (1) is ground while the base metal (11) is covered with a non-rotating umbrella-shaped member (21). Grinding method.

3. A base metal (11), a grindstone spindle (12) having one end supported by the base metal (11); a grindstone (13) attached to the grindstone spindle (12) and rotating together with the grindstone spindle (12) to grind the inner diameter of the workpiece (1); Equipped with a guide shape (15a, 17, 18, 18a) is provided on the base metal (11) so that the grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding portion of the workpiece (1) while changing its flow direction; The base metal (11) is a truncated cone portion (15) having the grindstone shaft (12) mounted at its top; a cylindrical portion (16) connected to the bottom of the truncated cone portion (15); having a concave surface (15a) is provided on an outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a), an inclination angle θ of the concave surface (15a) at the apex of the truncated cone portion (15) with respect to the grindstone spindle (12) is equal to or greater than 0° and is equal to or smaller than 20°; The inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), At the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. Shafted whetstone.

4. A base metal (11), a grindstone spindle (12) having one end supported by the base metal (11); a grindstone (13) attached to the grindstone spindle (12) and rotating together with the grindstone spindle (12) to grind the inner diameter of the workpiece (1); Equipped with a guide shape (15a, 17, 18, 18a) is provided on the base metal (11) so that the grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding portion of the workpiece (1) while changing its flow direction; The base metal (11) is a truncated cone portion (15) having the grindstone shaft (12) mounted at its top; a cylindrical portion (16) connected to the bottom of the truncated cone portion (15); having a plurality of twisted blades (17) are provided on an outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a); Shafted whetstone.

5. The grindstone according to claim 4, a concave surface (15a) is further provided as the guide shape (15a, 17, 18, 18a) on an outer circumferential surface of the truncated cone portion (15) between the plurality of blades (17), an inclination angle θ of the concave surface (15a) at the apex of the truncated cone portion (15) with respect to the grindstone spindle (12) is equal to or greater than 0° and is equal to or smaller than 20°; The inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), At the bottom of the truncated cone portion (15), the concave surface (15a) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less. Shafted whetstone.

6. The grindstone according to claim 4 or 5, A cover member (19) is provided on the truncated cone portion (15) so as to cover the plurality of blades (17). Shafted whetstone.

7. A base metal (11), a grindstone spindle (12) having one end supported by the base metal (11); a grindstone (13) attached to the grindstone spindle (12) and rotating together with the grindstone spindle (12) to grind the inner diameter of the workpiece (1); Equipped with a guide shape (15a, 17, 18, 18a) is provided on the base metal (11) so that the grinding fluid discharged toward the outer peripheral surface of the base metal (11) is supplied to the grinding portion of the workpiece (1) while changing its flow direction; The base metal (11) is a truncated cone portion (15) having the grindstone shaft (12) mounted at its top; a cylindrical portion (16) connected to the bottom of the truncated cone portion (15); having A plurality of twisted grooves (18) are provided on the outer circumferential surface of the truncated cone portion (15) as the guide shape (15a, 17, 18, 18a). Shafted whetstone.

8. The grindstone according to claim 7, a concave surface (18a) is further provided as the guide shape (15a, 17, 18, 18a) on a bottom surface of the plurality of grooves (18), an inclination angle θ of the concave surface (18a) at the apex of the truncated cone portion (15) with respect to the grindstone spindle (12) is equal to or greater than 0° and is equal to or smaller than 20°; The inclination angle θ increases from the apex to the bottom of the truncated cone portion (15), the concave surface (18a) at the bottom of the truncated cone portion (15) is connected to the outer circumferential surface of the cylindrical portion (16) at an angle φ of 40° or more and 90° or less; Shafted whetstone.

9. The grindstone according to claim 7 or 8, A cover member (19) is provided on the truncated cone portion (15) so as to cover the plurality of grooves (18). Shafted whetstone.

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