Honing tool

Abstract

To provide a honing tool capable of simultaneously and highly accurately grinding respective inner walls of a plurality of workpieces.SOLUTION: The hone tool 1 includes a grind part 13, a tool body 12 which has a long cylindrical shape and in which four slit J1 extending along a cylindrical shaft 12a direction and into which the grind part 13 is inserted are provided at an end on a - Z direction side, and an end on a + Z direction side is fixed to a rotary main spindle, and an extension rod inserted into the tool body 12. The tool body 12 has two guide parts 121, 122 provided on both sides of the slit 12a in the longitudinal direction. The guide portions 121 and 122 include four first grooves 121b and 122b extending in the direction of the cylinder axis J1 on the side walls thereof, and four second grooves 121a and 122a spirally extending around the cylinder axis J1 between the four first grooves 121b and 122b of the side walls.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a honing tool. [Background technology]

[0002] A honing tool has been proposed that includes a rod that can move back and forth in the axial direction, a grinding stone mounting plate that has a honing stone at its radially outer end and a radially inner end that can slide on the outer surface of the rod, biasing members that are provided at both axial ends of the grinding stone mounting plate and support the grinding stone mounting plate by biasing it toward the axial center, and a cylindrical tool body that covers the outer periphery of the rod and has insertion holes formed therein through which the honing stone and grinding stone mounting plate are inserted with gaps in the circumferential direction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-131347 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, there is a demand for realizing high throughput in the workpiece machining process by using a honing tool such as that described in Patent Document 1 to grind the inner walls of multiple cylindrical workpieces stacked with their cylindrical axes aligned. In this case, there is a demand for grinding the inner walls of each of the multiple cylindrical workpieces with high precision by restricting the multiple workpieces from moving relative to each other in a direction perpendicular to the cylindrical axis direction during honing of the multiple workpieces, while introducing more grinding fluid into the workpieces to improve grinding performance.

[0005] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a honing tool that can grind the inner walls of multiple workpieces simultaneously with high precision. [Means for solving the problem]

[0006] In order to achieve the above object, the honing tool according to the present invention comprises: A honing tool attached to a tip of a rotary spindle of a honing device, which hones the inner wall of each of a plurality of workpieces having machining holes and stacked so that the central axes of the machining holes coincide, a grinding portion having a grinding surface and a first tapered surface inclined with respect to the grinding surface on the opposite side to the grinding surface; a tool body having a long cylindrical shape, the tool body having a slit at one end in the cylindrical axis direction extending along the cylindrical axis direction, the slit through which the grinding portion is inserted so that the first tapered surface is positioned inward with the first tapered surface approaching the cylindrical axis as it approaches the one end in the cylindrical axis direction, and the other end in the cylindrical axis direction fixed to the rotation spindle; an extension rod having a rod-like shape and a second tapered surface inclined toward one end along the longitudinal direction so as to approach a first central axis along the longitudinal direction, and the extension rod being inserted into the inside of the tool body so that the second tapered surface is in surface contact with the first tapered surface; The tool body has two cylindrical guide portions that are provided on both sides of the slit in the longitudinal direction of the tool body and that restrict relative movement of the plurality of workpieces in a direction perpendicular to a cylindrical axis direction during honing of the plurality of workpieces, The guide portion has a plurality of first grooves that extend along the cylindrical axis direction in the side wall of the guide portion and communicate outwardly with both ends of the guide portion in the cylindrical axis direction, and a plurality of second grooves that extend spirally around the cylindrical axis between the plurality of first grooves in the circumferential direction around the cylindrical axis of the side wall. [Effects of the Invention]

[0007] According to the present invention, by providing guide portions on both sides of the slit in the longitudinal direction of the tool body, it is possible to prevent the multiple workpieces from shifting relative to each other in a direction perpendicular to the cylindrical axis direction during honing of the multiple workpieces. Furthermore, since the guide portion of the tool body is formed with a first groove and a second groove, the introduction of grinding fluid into the periphery of the slit and the discharge of grinding fluid from the periphery of the slit are promoted through the first groove and the second groove during honing of the multiple workpieces. Therefore, the accumulation of chips between the inner wall of each of the multiple workpieces and the grinding portion and the excessive increase in friction between the inner wall and the grinding portion during honing of the multiple workpieces are suppressed, thereby suppressing poor grinding of the inner wall of the workpieces. Therefore, the inner walls of each of the multiple workpieces can be ground simultaneously with high precision. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic view of a honing device according to an embodiment of the present invention. [Figure 2] FIG. 1A is a cross-sectional view showing a part of a honing tool according to an embodiment, and FIG. 1B is a cross-sectional view taken along line AA of FIG. [Figure 3] 1 is a side view showing a part of a honing tool according to Example 1 of an embodiment. [Figure 4] FIG. 10 is a side view showing a part of a honing tool according to Example 2 of the embodiment. [Figure 5] FIG. 10 is a side view showing a part of a honing tool according to Example 3 of the embodiment. [Figure 6] FIG. 10 is a side view showing a part of a honing tool according to Example 4 of the embodiment. [Figure 7] FIG. 1 is a side view showing a part of a honing tool according to Comparative Example 1. [Figure 8] FIG. 10 is a side view showing a part of a honing tool according to Comparative Example 2. [Figure 9] FIG. 2 is a schematic cross-sectional view showing the arrangement of multiple workpieces during honing. [Figure 10]FIG. 1A is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Comparative Example 1, FIG. 1B is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Comparative Example 2, and FIG. 1C is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Example 2. [Figure 11] FIG. 1(A) is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Example 1, FIG. 1(B) is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Example 3, and FIG. 1(C) is a diagram showing the results of measuring the inner diameter dimension of a workpiece after honing immediately after starting to use the honing tool according to Example 4. [Figure 12] 1A is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Comparative Example 1 and after honing 30 times; FIG. 1B is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Comparative Example 2 and after honing 30 times; and FIG. 1C is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Example 2 and after honing 30 times. [Figure 13] FIG. 1A is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Example 1 and after honing 30 times; FIG. 1B is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Example 3 and after honing 30 times; and FIG. 1C is a diagram showing the results of measuring the surface roughness of the inner wall of a workpiece immediately after starting to use the honing tool according to Example 4 and after honing 30 times. [Figure 14]FIG. 1A is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Comparative Example 1 until after 30 honing processes; FIG. 1B is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Comparative Example 2 until after 30 honing processes; and FIG. 1C is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 2 until after 30 honing processes. [Figure 15] FIG. 1A is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 1 until after 30 honing processes; FIG. 1B is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 3 until after 30 honing processes; and FIG. 1C is a diagram showing the transition of the maximum current value of the current supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 4 until after 30 honing processes. [Figure 16] (A) is a diagram showing the change in the amount of expansion of the grinding stone during honing processing from immediately after the start of use of the honing tool according to Comparative Example 1 until after 30 times of use, (B) is a diagram showing the change in the amount of expansion of the grinding stone during honing processing from immediately after the start of use of the honing tool according to Comparative Example 2 until after 30 times of use, and (C) is a diagram showing the change in the amount of expansion of the grinding stone during honing processing from immediately after the start of use of the honing tool according to Example 2 until after 30 times of use. [Figure 17] (A) is a diagram showing the change in the amount of expansion of the grinding wheel during honing processing from immediately after the start of use of the honing tool of Example 1 until after 30 times of use, (B) is a diagram showing the change in the amount of expansion of the grinding wheel during honing processing from immediately after the start of use of the honing tool of Example 3 until after 30 times of use, and (C) is a diagram showing the change in the amount of expansion of the grinding wheel during honing processing from immediately after the start of use of the honing tool of Example 4 until after 30 times of use. [Figure 18]Photograph (A) is a photograph showing one state of the honing tool according to Example 2 during use, and photograph (B) is a photograph showing another state of the honing tool according to Example 2 during use. [Figure 19] 1A is a photograph showing one state of the honing tool according to Example 1 during use, and FIG. 1B is a photograph showing another state of the honing tool according to Example 1 during use. [Figure 20] Photograph (A) is a photograph showing one state of the honing tool according to Example 3 during use, and photograph (B) is a photograph showing another state of the honing tool according to Example 3 during use. [Figure 21] Photograph (A) is a photograph showing one state of the honing tool according to Example 4 during use, and photograph (B) is a photograph showing another state of the honing tool according to Example 4 during use. DETAILED DESCRIPTION OF THE INVENTION

[0009] A honing tool according to an embodiment of the present invention will be described below with reference to the drawings. The honing tool according to the embodiment is attached to the tip of a rotating spindle of a honing machine and is used to hone the inner surfaces of machining holes in multiple cylindrical workpieces stacked with the same cylindrical axis. The honing tool includes a grinding portion having a grinding surface and a first tapered surface on the opposite side of the grinding surface that is inclined relative to the grinding surface; a long, cylindrical tool body having a slit at one end of the cylindrical axis extending along the cylindrical axis and through which the grinding portion is inserted so that the first tapered surface approaches the cylindrical axis as it approaches the one end of the cylindrical axis, with the first tapered surface positioned inward, and the other end of the cylindrical axis fixed to the rotating spindle; and a rod-shaped extension rod having a second tapered surface inclined toward one of the longitudinal ends thereof and approaching the longitudinal central axis as it approaches the longitudinal central axis. The extension rod is inserted into the tool body so that the second tapered surface is in surface contact with the first tapered surface. The tool body has two cylindrical guide portions provided on both sides of the slit in the longitudinal direction of the tool body and restricting relative movement of the multiple workpieces in a direction perpendicular to the cylindrical axis direction during machining of the multiple workpieces. The guide portions also have a plurality of first grooves extending along the cylindrical axis direction in the side wall of the guide portion and communicating with both ends of the guide portion in the cylindrical axis direction outward, and a plurality of second grooves extending spirally around the cylindrical axis between the plurality of first grooves in the circumferential direction around the cylindrical axis of the side wall.

[0010] As shown in FIG. 1, a honing apparatus 100 according to this embodiment processes the inner walls Wa of workpieces W (five workpieces in FIG. 1) each having a workpiece hole Wh. The workpieces W are stacked so that the central axes of the workpiece holes Wh are aligned. The honing apparatus 100 includes a honing tool 1, a rotating spindle 2, a rotation drive unit 5, a reciprocating drive unit 4, an expansion drive unit 6, a machine body 3, and a workpiece holding device 7. In FIG. 1, five workpieces W1, W2, ..., W5 are arranged such that the central axes J10 of the workpiece holes Wh are aligned with the central axis J0 of the rotating spindle 2. The rotating spindle 2 is supported by the machine body 3 and is rotatable around the central axis J0. The rotation drive unit 5 rotates the rotating spindle 2. The reciprocating drive unit 4 moves the rotating spindle 2 back and forth in the vertical direction. The expansion drive unit 6 expands and moves the grinding unit 13 via an expansion rod 11, which will be described later. The workpiece holding device 7 holds five workpieces W1, W2, ..., W5 so that they can move freely in a direction perpendicular to the Z-axis direction. The machine body 3 supports the rotary spindle 2, as well as the rotary drive unit 5, the reciprocating drive unit 4, the expansion drive unit 6, and the workpiece holding device 7.

[0011] As shown in Figures 2(A) and 2(B), the honing tool 1 includes a grinding portion 13, a tool body 12, an extension rod 11, and a shank portion 20. The Z-axis direction in Figures 2(A) to 6 coincides with the central axis J0 of the aforementioned rotating spindle 2, the cylindrical axis J1 of the tool body 12, and the central axis J2 of the extension rod 11, which will be described later. The shank portion 20 is attached to the lower end of the rotating spindle 2. With the honing tool 1 in a state where the shank portion 20 is fixed to the end of the rotating spindle 2 on the -Z direction side, the cylindrical axis J1 of the tool body 12 and the central axis J2 of the extension rod 11 approximately coincide with the central axis J0 of the rotating spindle 2.

[0012] As shown in FIG. 2A, the grinding unit 13 includes a rectangular prism-shaped grinding wheel 131 and a plate-shaped grinding wheel head 132 to which the grinding wheel 131 is bonded at its end faces. The grinding wheel 131 is made of minute diamond abrasive grains, CBN abrasive grains, or the like, bonded with a bonding material. The grinding wheel head 132 is made of a metal such as aluminum or steel, or a resin material such as epoxy resin or phenol resin. The grinding wheel 131 has a grinding surface 13a that contacts the inner wall Wa of the machining hole Wh in the workpiece W. The grinding wheel head 132 has a tapered surface 13b on the opposite side from the grinding wheel 131, which is inclined relative to the grinding surface 13a of the grinding wheel 131. Furthermore, both ends of the grinding wheel head 132 in the Z-axis direction protrude outward from both ends of the grinding wheel 131 in the Z-axis direction, and biasing members 171 and 172, described later, are in elastic contact with the protruding portions.

[0013] The tool body 12 has a long cylindrical shape. One end of the tool body 12 in the direction of the central axis J1 along the longitudinal direction, i.e., the end on the -Z direction side, is provided with a slit 12a extending along the cylindrical axis J1. Two guide portions 121, 122 are formed on both sides of the slit 12a in the Z direction to restrict relative movement of the multiple workpieces W in a direction perpendicular to the central axis J10 of the machining hole Wh during honing of the multiple workpieces W. The other end of the tool body 12 in the direction of the cylindrical axis J1, i.e., the end on the +Z direction side, is fixed to the rotating spindle 2 via a shank portion 20. As shown in FIG. 2(B), four slits 12a are provided at equal intervals around the cylindrical axis J1. As shown in FIG. 2(A), the grinding portion 13 is inserted through the slit 12a so that the tapered surface 13b approaches the cylindrical axis J1 as it extends toward the -Z direction, and the tapered surface 13b is positioned inside the tool body 12. The end of the tool body 12 on the +Z direction side is fixed to the shank portion 20. A step portion 12f is provided on the inside of the tool body 12 to restrict the movement range of the extension rod 11 in the +Z direction.

[0014] 2(B) and 3 to 6, the tool body 12 has two cylindrical guide portions 121, 122 provided on both sides of the slit 12a in the longitudinal direction of the tool body, i.e., in the Z-axis direction. The guide portions 121, 122 restrict relative movement of the five workpieces W1, W2, ..., W5 in a direction perpendicular to the cylindrical axis J1 during machining of the workpieces W1, W2, ..., W5. As shown in FIGS. 3 to 6, the guide portions 121, 122 each have a plurality of first grooves 121b, 122b and a plurality of second grooves 121a, 122a. The first grooves 121b, 122b extend along the cylindrical axis J1 in the side walls of the guide portions 121, 122 and communicate with both ends of the guide portions 121, 122 in the cylindrical axis J1 direction, i.e., in the Z-axis direction. The second grooves 121a, 122a extend spirally around the cylindrical axis J1 between the plurality of first grooves 121b, 122b in the circumferential direction around the cylindrical axis J1 of the side walls of the guide portions 121, 122.

[0015] Here, the cross-sectional shape of the first grooves 121b, 122b perpendicular to the direction of the cylinder axis J1 is curved so as to be convex toward the cylinder axis J1. Furthermore, at intersections P11, P12 between a virtual plane VPL1 that includes the cylinder axis J1 and passes through the portions of the side walls of the guide portions 121, 122 where the second grooves 121a, 122a are formed and a second center axis along the extension direction of the second grooves 121a, 122a, when viewed from the extension direction of a virtual line that is perpendicular to the cylinder axis J1 and passes through the intersections P11, P12, the acute angles de11, de12 formed by the extension direction of the second grooves 121a, 122a with respect to the cylinder axis J1 are set to be between 15 degrees and 45 degrees. Note that FIG. 3 shows Example 1 in which the angles de11, de12 are set to 30 degrees, and FIG. 4 shows Example 2 in which the angles de11, de12 are set to 15 degrees. FIG. 5 shows Example 3 in which the angles de11 and de12 are set to 45 degrees. FIG. 6 shows Example 4 in which the angles de11 and de12 are set to 45 degrees, and portions of the two second grooves 121a and 121b adjacent in the circumferential direction around the cylindrical axis J1 are aligned parallel to the cylindrical axis J1. The cross-sectional shapes of the second grooves 121a and 122a perpendicular to their extension direction are curved so as to be convex toward the cylindrical axis J1. The guide portion 122 has a shape that narrows in diameter as it extends in the -Z direction. As a result, when the honing tool 1 is inserted into the machining hole Wh from the +Z direction side of the workpieces W1, W2, …, W5, the workpieces W1, W2, …, W5 are guided so that the central axis J10 of the machining hole Wh coincides with the cylindrical axis J1 of the honing tool 1.

[0016] Returning to Figure 2(A), further, between the adjacent portion on the -Z direction side of the guide portion 121 in the cylindrical axis J1 direction of the tool body 12 and the adjacent portion on the +Z direction side of the guide portion 122, an annular groove 123b is formed around the entire circumference of the cylindrical axis J1 on the side wall of the tool body 12, and into which are fitted spring members 171, 172 formed in an annular shape from an elastic material such as rubber.

[0017] The extension rod 11 is long and rod-shaped and has a tapered surface 11a that is inclined toward the central axis J2 along the longitudinal direction as it approaches the tip, i.e., the -Z direction. The extension rod 11 is connected to the aforementioned extension drive unit 6 and is moved along the Z axis direction by the extension drive unit 6. Four tapered surfaces 11a are provided at equal intervals in the circumferential direction around the central axis J2 of the extension rod 11. The extension rod 11 also has a movement limiting portion 11c that limits the movement range of the extension rod 11 in the +Z direction when inserted inside the tool body 12, and a guide portion 11b that guides the grinding portion 13 in the direction along the central axis J2. The extension rod 11 is inserted into the tool body 12 so that the movement limiting portion 11c is located on the -Z direction side of the step portion 12f of the tool body 12 inside the tool body 12. For example, when the extension rod 11 moves in the +Z direction and the +Z-direction end of the movement limiting portion 11c abuts against the step portion 12f, movement of the extension rod 11 in the +Z direction is restricted. The guide portion 11b is formed by a portion that protrudes in a direction perpendicular to the central axis J2 from between two adjacent tapered surfaces 11a of the extension rod 11 in the circumferential direction around the central axis J2. As shown in FIG. 2(A), the extension rod 11 is inserted into the inside of the tool body 12 so that the tapered surface 11a is in surface contact with the tapered surface 13b of the grinding portion 13. When the extension rod 11 moves in the -Z direction, the grinding portion 13 is pushed outward. On the other hand, when the extension rod 11 moves in the +Z direction, the grinding portion 13 is pulled back into the tool body 12 by the biasing force of the biasing members 171 and 172 that are in elastic contact with both ends of the wheel head 132 of the grinding portion 13 in the Z-axis direction.

[0018] Next, the performance of the honing tool according to the present embodiment will be described in comparison with Comparative Examples 1 and 2. As shown in FIG. 7, a honing tool 9001 according to Comparative Example 1 includes a grinding portion 13 and a tool body 9012. Note that in FIG. 7, the same components as those in the embodiment are denoted by the same reference numerals as in FIGS. 3 to 6. The honing tool 9001 also includes the aforementioned extension rod 11 inserted inside the tool body 9012 and a shank portion 20. Two cylindrical guide portions 9121 and 9122 are formed on both sides of the slit 12a in the Z-axis direction of the tool body 9012. The lengths L91 and L92 of the guide portions 9121 and 9122 in the Z-axis direction are set to approximately ¼ of the lengths L11 and L12 of the guide portions 121 and 122 in the Z-axis direction, respectively. Further, the guide portions 9121 and 9122 are formed with notches 9121b and 9122b at four positions in the circumferential direction around the cylindrical axis J91.

[0019] As shown in FIG. 8, the honing tool 10001 according to Comparative Example 2 includes a grinding portion 13 and a tool body 10012. Note that components in FIG. 8 that are similar to those in the embodiment are denoted by the same reference numerals as those in FIGS. 3 to 6. The honing tool 10001 also includes the aforementioned extension rod 11 inserted inside the tool body 10012 and a shank portion 20. Two cylindrical guide portions 10121 and 10122 are formed on both sides of the slit 12a in the Z-axis direction of the tool body 10012. The lengths L11 and L11 of the guide portions 10121 and 10122 in the Z-axis direction are set to be the same as the lengths L11 and L12 of the guide portions 121 and 122 according to the embodiment. First grooves 121b and 122b are formed at four locations in the circumferential direction around the cylindrical axis J101 of the guide portions 10121 and 10122.

[0020] Honing tools 1 according to Examples 1 to 4 were prepared, each differing from the other in at least one of the angles de11 and de12 of the first flutes 121b and 122b and the number of grooves on the first flutes 121b and 122b. For the honing tool 1 according to Example 1, the angles de11 and de12 of the first flutes 121b and 122b were 30 degrees, and the number of grooves was four. For the honing tool 1 according to Example 2, the angles de11 and de12 of the first flutes 121b and 122b were 15 degrees, and the number of grooves was four. For the honing tool 1 according to Example 3, the angles de11 and de12 of the first flutes 121b and 122b were 45 degrees, and the number of grooves was two. For the honing tool 1 according to Example 4, the angles de11 and de12 of the first flutes 121b and 122b were 45 degrees, and the number of grooves was four.

[0021] Here, we will explain the results of comparing the states after and during machining of five workpieces W1, W2, ..., W5 machined with the honing tool 1 according to Examples 1 to 4 and the honing tools 9001 and 10001 according to Comparative Examples 1 and 2. Here, we will explain the results of comparing the distribution of the inner diameter of the machined hole Wh after machining of the five workpieces W1, W2, ..., W5, the surface roughness of the inner wall Wa of the machined hole Wh, and the maximum current value of the current supplied to the rotation drive unit 5 during machining. Regarding the inner diameter of the machined hole Wh, we compared the results of measuring the inner diameter dimensions at 10 locations above and below Po_i (i = 1, 2, ..., 5) along the direction of the central axis J10 of the machined hole Wh shown in FIG. 9. As shown in FIG. 10(A), the inner diameter dimensions of the workpieces machined immediately after starting use of the honing tool according to Comparative Example 1 exceeded the upper limit of 19.645 mm of the target dimension range, which corresponds to the area between the two dashed lines, for all workpieces W1, W2, ..., W5. In contrast, as shown in FIGS. 10(B) to 11(B), for the honing tool 1001 according to Comparative Example 2 and the honing tools 1 according to Examples 1 to 3, the inner diameter dimension of the -Z direction side (lower side) of workpiece W5, which was located furthest in the -Z direction among the five workpieces W1, W2, ..., W5, fell below the lower limit of 19.635 mm of the target dimension range. However, the inner diameter dimensions at the other nine measurement positions were all within the target dimension range. Furthermore, as shown in FIG. 11(C), for the honing tool 1 according to Example 4, the inner diameter dimensions at all measurement positions for the five workpieces W1, W2, ..., W5 were within the target dimension range.

[0022] In addition, the surface roughness Rz of the inner wall of the machined hole Wh of five workpieces W1, W2, ..., W5 was compared immediately after starting use of the honing tool and after 30 treatments. Here, the results of measuring the surface roughness Rz at 15 locations (Po_i, Po_i-up, Po_i-middle, and Po_i-down) along the central axis J10 direction of the machined hole Wh shown in FIG. 9 were compared. As shown in FIG. 12(A), the surface roughness Rz of the inner wall of the machined hole Wh of workpieces W1, W2, ..., W5 immediately after starting use of the honing tool according to Comparative Example 1 was lower than the surface roughness Rz of the inner wall of the machined hole Wh after 30 treatments. Furthermore, the variation in the surface roughness Rz of the inner wall of the workpiece immediately after starting use of the honing tool according to Comparative Example 1 in the central axis J10 direction of the machined hole Wh was relatively large, with a variation of approximately 1.7 μm. 12(B), the surface roughness Rz of the workpiece after machining immediately after starting to use the honing tool according to Comparative Example 2 and after 30 treatments was 1.5 to 2.0 μm, which was relatively low. Also, as shown in FIG. 13(B), the surface roughness Rz of the workpiece after machining immediately after starting to use the honing tool according to Example 3 was 2.2 to 3.3 μm, but the surface roughness Rz of the inner wall of the machined hole Wh after 30 treatments had decreased to 2.2 μm or less.

[0023] 12(C), 13(A) and 13(C), the surface roughness Rz of the workpieces after machining immediately after starting to use the honing tools according to Examples 1, 2 and 4 and after 30 treatments was 3.0 μm or more, which was relatively high. From this, it was found that by forming four or more second grooves 121a, 122a in the guide portions 121, 122, the retention of chips between the inner walls of the workpieces W1, W2, ..., W5 and the grinding portion 13 during machining of the workpieces W1, W2, ..., W5 was suppressed, and the cleanability of the space between the inner walls and the grinding portion 13 by the grinding fluid was improved.

[0024] Furthermore, the transitions in the maximum current value of the current supplied to the rotary drive unit 5 from immediately after the start of use of the honing tool until 30 treatments were performed were compared. As shown in FIGS. 14(A) and (B), the maximum current value when using the honing tools according to Comparative Examples 1 and 2 remained above 4.5 A until 28 treatments were performed. Furthermore, as shown in FIG. 15(B), the maximum current value when using the honing tool according to Example 3 remained above 3.8 A and below 4.8 A. On the other hand, as shown in FIGS. 14(C) and 15(A) and (C), the maximum current value when using the honing tools according to Examples 1, 2, and 4 remained below 4.6 A. This indicates that by forming four or more second grooves 121a, 122a in the guide portions 121, 122, excessive increases in friction between the inner walls of the workpieces W1, W2, …, and W5 and the grinding portion 13 during machining of the workpieces W1, W2, …, and W5 are suppressed.

[0025] The transition of the expansion amount of the ground portion 13 during the honing process from immediately after the start of use of the honing tool until the 30th honing process was compared. As shown in FIGS. 16(A) and (B), when the honing tools according to Comparative Examples 1 and 2 were used, the expansion amount immediately after the start of use was relatively large, at 295 μm or more. Furthermore, as shown in FIG. 17(B), when the honing tool according to Example 3 was used, the expansion amount immediately after the start of use was also relatively large, at approximately 305 μm. On the other hand, as shown in FIGS. 16(C) and 17(A) and (C), when the honing tools according to Examples 1, 2, and 4 were used, the expansion amount immediately after the start of use was less than 295 μm. From this, it can be seen that by forming four or more second grooves 121a, 122a in guide portions 121, 122, an excessive increase in friction between the inner walls of each of workpieces W1, W2, ..., W5 and grinding portion 13 during machining of workpieces W1, W2, ..., W5 is suppressed, especially immediately after starting to use the honing tool.

[0026] Next, for Comparative Example 2 and Examples 1 to 3, in which the Z-axis lengths L11 and L12 of the guide portions 121 and 122 were set to the same value, a transparent jig was used, which had a transparent, cylindrical straight pipe portion having an inner diameter approximately equal to the machining hole Wh of the workpieces W1, W2, …, W5, and a hopper portion formed integrally with the vertically upper end of the straight pipe portion. The honing tool 10001, 1 was inserted into the straight pipe portion of the transparent jig, and the fluidity of the grinding oil was evaluated when the grinding oil was poured into the hopper portion. First, the honing tool 10001, 1 was inserted into the straight pipe portion, and then, without rotating the honing tool 10001, 1, the amount of grinding oil flowing vertically downward from the straight pipe portion, i.e., the amount of grinding oil permeation, was compared. The results shown in Table 1 were obtained.

[0027] [Table 1]

[0028] As shown in Table 1, the amount of grinding oil used in the honing tool 10001 of Comparative Example 2 was 216.7 g, while the amounts used in Examples 1 to 3 were 235 g or more. This indicates that the formation of first grooves 121b and 122b in guide portions 121 and 122 enhances the fluidity of the grinding oil. Furthermore, after inserting the honing tool 1 of Example 2 into the straight pipe section, the honing tool 1 was reciprocated and rotated along the Z-axis within the straight pipe section while continuously supplying grinding oil into the hopper section at the same flow rate for 30 seconds. The amount of grinding oil flowing vertically downward from the straight pipe section, i.e., the amount of grinding oil permeated, was compared. The results shown in Table 2 were obtained.

[0029] [Table 2]

[0030] As shown in Table 2, for the honing tool 1 according to Example 2, no difference in fluidity was observed depending on whether or not there was reciprocating movement in the Z-axis direction and rotational drive, and depending on the axial speed and rotational speed when reciprocating in the Z-axis direction.

[0031] 18(A) to 21(B) show the state when the honing tools 1 according to Examples 2, 1, 3, and 4 were inserted into the straight pipe section, grinding oil was poured into the hopper section, and then the honing tools 1 were reciprocated along the Z-axis direction and rotated within the straight pipe section. As shown in FIGS. 18(A) and 18(B), when the honing tool 1 according to Example 2 was used, the grinding oil was observed flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. As shown in FIGS. 19(A) and 19(B), when the honing tool 1 according to Example 1 was used, the grinding oil was observed flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. Furthermore, as shown in Figures 20(A) and (B), when the honing tool 1 according to Example 3 was used, the grinding fluid was observed flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. Also, as shown in Figures 21(A) and (B), when the honing tool 1 according to Example 4 was used, the grinding fluid was observed flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. Furthermore, particularly with the honing tool 1 according to Example 4, an increase in the flow rate of grinding oil near the grinding portion 13 was observed. These observation results demonstrate that when chips are present near the grinding portion 13 of the honing tool 1, the chips can be discharged vertically downward together with the grinding oil. The honing tool according to Example 4 is particularly effective in discharging chips vertically downward together with the grinding oil.

[0032] As described above, in the honing tool 1 according to the present embodiment, the guide portions 121, 122 are provided on both sides of the slit 12a in the Z-axis direction of the tool body 12, thereby preventing the workpieces W1, W2, ..., W5 from shifting relative to one another in directions perpendicular to the cylindrical axis J1, i.e., in the XY directions, during machining of the workpieces W1, W2, ..., W5. Furthermore, the first grooves 121b, 122b and the second grooves 121a, 122a are formed in the guide portions 121, 122 of the tool body 12, thereby facilitating the introduction of grinding fluid into the periphery of the slit 12a and the discharge of grinding fluid from the periphery of the slit 12a through the first grooves 121b, 122b and the second grooves 121a, 122a during machining of the workpieces W1, W2, ..., W5. Therefore, during machining of the plurality of workpieces W1, W2, ..., W5, accumulation of chips between the inner wall of each of the plurality of workpieces W1, W2, ..., W5 and the grinding section 13 and an excessive increase in friction between the inner wall and the grinding section 13 are suppressed, thereby suppressing poor grinding of the inner walls of the workpieces W1, W2, ..., W5. Therefore, the inner walls of each of the plurality of workpieces W1, W2, ..., W5 can be ground simultaneously and with high precision.

[0033] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, in the embodiments, the number of grooves in the first grooves 121b and 122b may be less than three or may be five or more. Furthermore, the number of grooves in the second grooves 121a and 122a may be five or more.

[0034] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. The present invention includes any combination of the embodiments and modifications, and any combination to which appropriate modifications have been made. [Industrial Applicability]

[0035] The present invention is suitable as a honing tool to be attached to a honing device that performs honing. [Explanation of symbols]

[0036] 1: honing tool, 2: rotating spindle, 3: machine body, 4: reciprocating drive unit, 5: rotary drive unit, 6: extension drive unit, 11: extension rod, 11a, 13b: tapered surface, 11b: guide unit, 11c: movement limiting unit, 12: tool body, 12a: slit, 12f: step portion, 13: grinding unit, 13a: grinding surface, 20: shank portion, 100: honing processing device, 121, 122: guide unit, 121a, 122a: second groove, 121b, 122b: first groove, 131: grinding stone, 132: grinding stone head, 171, 172: biasing member, J0, J2, J10: central axis, J1: cylindrical axis, W1, W2, W3, W4, W5: workpiece, Wa: inner wall, Wh: machining hole

Claims

1. A honing tool attached to a tip of a rotary spindle of a honing device, which hones the inner wall of each of a plurality of workpieces having machining holes and stacked so that the central axes of the machining holes coincide, a grinding portion having a grinding surface and a first tapered surface on the opposite side of the grinding surface, the first tapered surface being inclined with respect to the grinding surface; a tool body having a long cylindrical shape, the tool body having a slit at one end in the cylindrical axis direction extending along the cylindrical axis direction, the slit through which the grinding portion is inserted so that the first tapered surface is positioned inward with the first tapered surface approaching the cylindrical axis as it approaches the one end in the cylindrical axis direction, and the other end in the cylindrical axis direction fixed to the rotation spindle; an extension rod having a rod-like shape and a second tapered surface inclined toward one end along the longitudinal direction so as to approach a first central axis along the longitudinal direction, and the extension rod being inserted into the inside of the tool body so that the second tapered surface is in surface contact with the first tapered surface; the tool body has two cylindrical guide portions provided on both sides of the slit in the longitudinal direction of the tool body, and restricting relative movement of the plurality of workpieces in a direction perpendicular to a cylindrical axis direction during honing of the plurality of workpieces, The guide portion has a plurality of first grooves extending along the cylindrical axis direction in a side wall of the guide portion and communicating outwardly with both ends of the guide portion in the cylindrical axis direction, and a plurality of second grooves extending spirally around the cylindrical axis between the plurality of first grooves in a circumferential direction around the cylindrical axis of the side wall. Honing tool.

2. a cross-sectional shape of the first groove perpendicular to the cylinder axis direction has a curved shape that is convex toward the cylinder axis; The honing tool of claim 1 .

3. At an intersection between an imaginary plane that includes the cylindrical axis and passes through a portion of the side wall of the guide portion where the second groove is formed and a second central axis along the extending direction of the second groove, when viewed from a direction along an imaginary line that is perpendicular to the cylindrical axis and passes through the intersection, an acute angle formed by the extending direction of the second groove with respect to the cylindrical axis is 15 degrees or more and 45 degrees or less.

3. The honing tool according to claim 1 or 2.

4. The plurality of second grooves is four or more.

3. The honing tool according to claim 1 or 2.

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