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 Art

[0002] There has been proposed a honing tool including a rod reciprocally movable in an axial direction, a grindstone mounting plate having a honing grindstone at a radially outer end portion and a radially inner end portion slidable on an outer peripheral surface of the rod, biasing members provided at both axial ends of the grindstone mounting plate and supporting the grindstone mounting plate by biasing it toward the axis center, and a tool body having a cylindrical shape covering an outer periphery of the rod and formed with an insertion hole through which the honing grindstone and the grindstone mounting plate are inserted with a gap in a circumferential direction (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is required to achieve high throughput in a workpiece processing step by grinding an inner wall of a workpiece in a state where a plurality of cylindrical workpieces are stacked so that their cylinder axes coincide with each other using a honing tool as described in Patent Document 1. In this case, during honing of a plurality of workpieces, while restricting relative movement of the plurality of workpieces in a direction orthogonal to the cylinder axis direction, more grinding fluid is introduced into the workpiece to improve the grinding ability, thereby grinding the inner walls of each of the plurality of cylindrical workpieces with high precision is required.

[0005] This invention has been made in view of the above reasons, and aims to provide a honing tool that can simultaneously and accurately grind the inner walls of multiple workpieces. [Means for solving the problem]

[0006] To achieve the above objective, the honing tool according to the present invention is A honing tool that is attached to the tip of the rotating spindle of a honing machine and hones the inner wall of the machining hole of each of a plurality of workpieces that are stacked so that the central axes of the machining holes coincide, A grinding section having a grinding surface and a first tapered surface on the opposite side of the grinding surface that is inclined with respect to the grinding surface, The tool body is long and cylindrical, and has a slit at one end in the direction of the cylinder axis through which the grinding portion is inserted, with the first tapered surface facing inward as it approaches the cylinder axis towards the end in the direction of the cylinder axis, and the other end in the direction of the cylinder axis is fixed to the rotating spindle. The tool comprises a rod-shaped extension rod having a second tapered surface that is inclined so as it approaches a first central axis along the longitudinal direction towards one end along the longitudinal direction, and an extension rod inserted inside the tool body such 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, which restrict the relative movement of the plurality of workpieces in a direction perpendicular to the cylindrical axis direction during the 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 with the outer ends of both ends in the cylindrical axis direction of the guide portion, and a plurality of second grooves that extend spirally around the cylindrical axis between the plurality of first grooves in the circumferential direction of the side wall around the cylindrical axis. [Effects of the Invention]

[0007] According to the present invention, guide portions are provided on both sides of the slit in the longitudinal direction of the tool body, which prevents multiple workpieces from shifting relative to each other in a direction perpendicular to the cylindrical axis direction during honing of multiple workpieces. Furthermore, since a first groove and a second groove are formed in the guide portion of the tool body, the introduction of grinding fluid to the area around the slit and the discharge of grinding fluid from the area around the slit are promoted through the first groove and the second groove during honing of multiple workpieces. Consequently, the accumulation of chips between the inner wall of each workpiece and the grinding portion, as well as an excessive increase in friction between the inner wall and the grinding portion, are suppressed during honing of multiple workpieces, thereby suppressing grinding defects on the inner walls of the workpieces. Therefore, the inner walls of each of the multiple workpieces can be ground simultaneously and with high precision. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a honing apparatus according to an embodiment of the present invention. [Figure 2] (A) is a cross-sectional view showing a part of a honing tool according to an embodiment, and (B) is a cross-sectional view taken along line AA of (A). [Figure 3] This is a side view showing a part of the honing tool according to Embodiment 1 of the embodiment. [Figure 4] This is a side view showing a part of the honing tool according to Embodiment 2 of the embodiment. [Figure 5] This is a side view showing a part of the honing tool according to Embodiment 3 of the embodiment. [Figure 6] This is a side view showing a part of the honing tool according to Embodiment 4 of the embodiment. [Figure 7] This is a side view showing a part of the honing tool related to Comparative Example 1. [Figure 8] This is a side view showing a part of the honing tool according to Comparative Example 2. [Figure 9] This is a schematic cross-sectional view showing the arrangement of multiple workpieces during honing. [Figure 10](A) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Comparative Example 1, (B) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Comparative Example 2, and (C) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Example 2. [Figure 11] (A) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Example 1, (B) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Example 3, and (C) is a figure showing the results of measuring the inner diameter of a workpiece after honing immediately after starting to use the honing tool according to Example 4. [Figure 12] (A) is a figure 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 30 honing treatments. (B) is a figure 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 30 honing treatments. (C) is a figure 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 30 honing treatments. [Figure 13] (A) is a figure 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 30 honing treatments. (B) is a figure 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 30 honing treatments. (C) is a figure 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 30 honing treatments. [Figure 14](A) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Comparative Example 1 to after 30 treatments, (B) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Comparative Example 2 to after 30 treatments, and (C) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 2 to after 30 treatments. [Figure 15] (A) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 1 to after 30 treatments, (B) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 3 to after 30 treatments, and (C) is a figure showing the change in the maximum current value supplied to the rotary drive unit during honing from immediately after the start of use of the honing tool according to Example 4 to after 30 treatments. [Figure 16] (A) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments for the honing tool according to Comparative Example 1, (B) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments for the honing tool according to Comparative Example 2, and (C) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments for the honing tool according to Example 2. [Figure 17] (A) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments of the honing tool according to Example 1, (B) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments of the honing tool according to Example 3, and (C) is a figure showing the change in the amount of expansion of the grinding wheel during honing from immediately after use to 30 treatments of the honing tool according to Example 4. [Figure 18](A) is a photograph showing one state during the use of the honing tool according to Example 2, and (B) is a photograph showing another state during the use of the honing tool according to Example 2. [Figure 19] (A) is a photograph showing one state during the use of the honing tool according to Example 1, and (B) is a photograph showing another state during the use of the honing tool according to Example 1. [Figure 20] (A) is a photograph showing one state during the use of the honing tool according to Example 3, and (B) is a photograph showing another state during the use of the honing tool according to Example 3. [Figure 21] (A) is a photograph showing one state during the use of the honing tool according to Example 4, and (B) is a photograph showing another state during the use of the honing tool according to Example 4.

Modes for Carrying Out the Invention

[0009] Hereinafter, the honing tool according to the embodiment of the present invention will be described with reference to the drawings. The honing tool according to this embodiment is attached to the tip of the rotating spindle of a honing processing apparatus, and is for honing the inner surface of the processing holes of a plurality of workpieces that are cylindrical and stacked so that their cylinder axes coincide. This honing tool includes a grinding part having a first tapered surface inclined with respect to the grinding surface on the side opposite to the grinding surface, and a long cylindrical shape. At one end in the cylinder axis direction, it extends along the cylinder axis direction, and a slit is provided through which the grinding part is inserted so that the first tapered surface side is arranged inside in a posture where the first tapered surface approaches the cylinder axis toward one end side in the cylinder axis direction. At the other end in the cylinder axis direction, a tool body fixed to the rotating spindle, a rod shape, having a second tapered surface inclined so as to approach the central axis along the longitudinal direction toward one end in the longitudinal direction, and the second tapered surface is inserted inside the tool body so as to be in surface contact with the first tapered surface, and an expansion rod. And the tool body is provided on both sides of the slit in the longitudinal direction of the tool body, and has two cylindrical guide parts that restrict the relative movement of the plurality of workpieces in a direction orthogonal to the cylinder axis direction during the processing of the plurality of workpieces. Further, the guide part has a plurality of first grooves that extend along the cylinder axis direction on the side wall of the guide part and communicate with the outside of both ends in the cylinder axis direction in the guide part, and a plurality of second grooves that extend spirally around the cylinder axis between the plurality of first grooves in the circumferential direction around the cylinder axis of the side wall.

[0010] As shown in Figure 1, the honing apparatus 100 according to this embodiment processes the inner wall Wa of each machining hole Wh of a plurality of workpieces W (five in Figure 1) that are stacked so that the central axes of the machining holes Wh coincide. This honing apparatus 100 comprises a honing tool 1, a rotary spindle 2, a rotary drive unit 5, a reciprocating drive unit 4, an expansion drive unit 6, a machine body 3, and a workpiece holding device 7. In Figure 1, five workpieces W1, W2, ..., W5 are arranged in a position where the central axis J10 of their machining holes Wh coincides with the central axis J0 of the rotary spindle 2. The rotary spindle 2 is supported by the machine body 3 and is rotatable around the central axis J0. The rotary drive unit 5 rotates the rotary spindle 2. The reciprocating drive unit 4 moves the rotary 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 in a direction perpendicular to the Z-axis direction. The machine body 3, together with the rotating spindle 2, supports the rotary drive unit 5, the reciprocating drive unit 4, the extension drive unit 6, and the workpiece holding device 7.

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

[0012] As shown in Figure 2(A), the grinding section 13 includes a rectangular prism-shaped grinding wheel 131 and a plate-shaped grinding wheel holder 132 to which the grinding wheel 131 is attached at its end. The grinding wheel 131 is made of minute diamond abrasive grains, CBN abrasive grains, etc., bonded together by a binder material. The grinding wheel holder 132 is made of a metal such as aluminum or steel, or a resin material such as epoxy resin or phenolic resin. The grinding wheel 131 has a grinding surface 13a that contacts the inner wall Wa of the processed hole Wh of the workpiece W, and the grinding wheel holder 132 has a tapered surface 13b that is on the opposite side from the grinding wheel 131 and is inclined with respect to the grinding surface 13a of the grinding wheel 131. Furthermore, both ends of the grinding wheel holder 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, which will be described later, are elastically in contact with each of these protruding portions.

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

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

[0015] Here, the cross-sectional shape of the first grooves 121b and 122b perpendicular to the direction of the cylindrical axis J1 is curved so as to be convex toward the cylindrical axis J1. Furthermore, at the intersection points P11 and P12 of the virtual plane VPL1, which includes the cylindrical axis J1 and passes through the portion where the second grooves 121a and 122a are formed on the side walls of the guide portions 121 and 122, and the second central axis along the direction of extension of the second grooves 121a and 122a, the acute angles de11 and de12 between the direction of extension of the cylindrical axis J1 and the direction of extension of the second grooves 121a and 122a, as viewed from the direction of extension of the virtual straight line perpendicular to the cylindrical axis J1 and passing through intersection points P11 and P12, are set to be between 15 degrees and 45 degrees. Note that Figure 3 shows Embodiment 1 in which angles de11 and de12 are set to 30 degrees, and Figure 4 shows Embodiment 2 in which angles de11 and de12 are set to 15 degrees. Figure 5 shows Embodiment 3, in which angles de11 and de12 are set to 45 degrees. Figure 6 shows Embodiment 4, in which angles de11 and de12 are set to 45 degrees, and parts of two adjacent second grooves 121a and 121b around the cylindrical axis J1 are parallel in the direction of the cylindrical axis J1. The cross-sectional shape of the second grooves 121a and 122a perpendicular to their extending direction is curved so as to be convex toward the cylindrical axis J1. The guide portion 122 has a shape that decreases in diameter toward the -Z direction. As a result, when the honing tool 1 is inserted into the inside of 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 their machining holes Wh coincides with the cylindrical axis J1 of the honing tool 1.

[0016] Returning to Figure 2(A), annular grooves 123b are formed in the side walls of the tool body 12, extending around the entire circumference of the cylindrical axis J1, between the adjacent portions of the guide portion 121 on the -Z direction and the adjacent portion of the guide portion 122 on the +Z direction. These grooves are formed to accommodate biasing members 171 and 172, which are annularly formed from an elastic material such as rubber.

[0017] The extension rod 11 is a long, rod-shaped instrument with a tapered surface 11a that is inclined so that it approaches the central axis J2 along its longitudinal direction as it moves toward the tip, i.e., toward 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 for limiting the range of movement of the extension rod 11 in the +Z direction when it is inserted inside the tool body 12, and a guide portion 11b for guiding the grinding portion 13 in the direction along the central axis J2. The extension rod 11 is inserted into the tool body 12 such that the movement limiting portion 11c is located toward the -Z direction side of the stepped portion 12f of the tool body 12 when it is inside the tool body 12. For example, when the expansion rod 11 moves in the +Z direction and the +Z-side end of the movement limiting portion 11c comes into contact with the stepped portion 12f, the movement of the expansion rod 11 in the +Z direction is restricted. The guide portion 11b consists of a portion that protrudes from between two adjacent tapered surfaces 11a in the circumferential direction around the central axis J2 of the expansion rod 11 in a direction perpendicular to the central axis J2. As shown in Figure 2(A), the expansion rod 11 is inserted inside the tool body 12 such that the tapered surface 11a makes surface contact with the tapered surface 13b of the grinding portion 13. When the expansion rod 11 moves in the -Z direction, the grinding portion 13 is pushed outward. On the other hand, when the expansion rod 11 moves in the +Z direction, the biasing force of the biasing members 171 and 172, which are elastically in contact with both ends of the grinding wheel base 132 in the Z-axis direction, pulls the grinding portion 13 back inside the tool body 12.

[0018] Next, the performance of the honing tool according to this embodiment will be described in comparison with Comparative Examples 1 and 2. As shown in Figure 7, the honing tool 9001 according to Comparative Example 1 comprises a grinding section 13 and a tool body 9012. Note that in Figure 7, components similar to those in the embodiment are denoted by the same reference numerals as in Figures 3 to 6. The honing tool 9001 also comprises the aforementioned expansion rod 11 inserted inside the tool body 9012 and a shank section 20. Two cylindrical guide sections 9121 and 9122 are formed on both sides of the slit 12a in the Z-axis direction of the tool body 9012. The Z-axis lengths L91 and L92 of the guide sections 9121 and 9122 are set to approximately 1 / 4 of the Z-axis lengths L11 and L12 of the guide sections 121 and 122 according to the embodiment. Furthermore, notches 9121b and 9122b are formed at four locations in the circumferential direction around the cylindrical shaft J91 of the guide sections 9121 and 9122.

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

[0020] Furthermore, as honing tools 1 according to the embodiments, honing tools 1 according to Embodiments 1 to 4 were prepared, each differing in at least one of the aforementioned angles de11 and de12 of the first grooves 121b and 122b, and the number of grooves in the first grooves 121b and 122b. Honing tool 1 according to Embodiment 1 had angles de11 and de12 of the first grooves 121b and 122b of 30 degrees and 4 grooves. Honing tool 1 according to Embodiment 2 had angles de11 and de12 of the first grooves 121b and 122b of 15 degrees and 4 grooves. Honing tool 1 according to Embodiment 3 had angles de11 and de12 of the first grooves 121b and 122b of 45 degrees and 2 grooves. Honing tool 1 according to Embodiment 4 had angles de11 and de12 of the first grooves 121b and 122b of 45 degrees and 4 grooves.

[0021] Here, we will describe the results of comparing the state of five workpieces W1, W2, ..., W5 after machining and during machining, using 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 describe the results of comparing the distribution of the inner diameter of the machined holes Wh after machining of the five workpieces W1, W2, ..., W5, the surface roughness of the inner wall Wa of the machined holes Wh, and the maximum current value supplied to the rotary drive unit 5 during machining. For the inner diameter of the machined holes 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 central axis J10 direction of the machined holes Wh shown in Figure 9. As shown in Figure 10(A), immediately after starting to use the honing tool according to Comparative Example 1, the internal diameter dimensions of the workpieces after machining exceeded the upper limit of the target dimension range of 19.645 mm, which corresponds to the area between the two dashed lines, for all workpieces W1, W2, ..., W5. In contrast, as shown in Figures 10(B) to 11(B), with the honing tool 1001 according to Comparative Example 2 and the honing tool 1 according to Examples 1 to 3, the internal diameter dimension on the -Z side (lower side) of workpiece W5, which is located furthest towards the -Z direction among the five workpieces W1, W2, ..., W5, fell below the aforementioned lower limit of the target dimension range of 19.635 mm. However, the internal diameter dimensions at the other nine measurement positions were all within the target dimension range. Furthermore, as shown in Figure 11(C), with the honing tool 1 according to Example 4, the internal diameter dimensions at all measurement positions of the five workpieces W1, W2, ..., W5 were within the target dimension range.

[0022] Furthermore, the surface roughness Rz of the inner walls of the machined holes Wh of five workpieces W1, W2, ..., W5 was compared immediately after starting to use the honing tool and after 30 treatments. Here, the results of measuring the surface roughness Rz at 15 locations (upper, middle, and lower Po_i, i=1, 2, ..., 5) along the central axis J10 direction of the machined hole Wh shown in Figure 9 were compared. As shown in Figure 12(A), the surface roughness Rz of the inner walls of the machined holes Wh of workpieces W1, W2, ..., W5 immediately after starting to use the honing tool according to Comparative Example 1 was lower than the surface roughness Rz of the inner walls of the machined holes Wh after 30 treatments. In addition, the variation in the surface roughness Rz of the inner walls of the machined holes Wh in the central axis J10 direction of the machined hole Wh immediately after starting to use the honing tool according to Comparative Example 1 was relatively large, with a variation of about 1.7 μm. Furthermore, as shown in Figure 12(B), the surface roughness Rz of the workpiece after processing was relatively low, at 1.5 to 2.0 μm immediately after starting to use the honing tool according to Comparative Example 2 and after 30 processing cycles. Also, as shown in Figure 13(B), the surface roughness Rz of the workpiece after processing was 2.2 to 3.3 μm immediately after starting to use the honing tool according to Example 3, but the surface roughness Rz of the inner wall of the processed hole Wh after 30 processing cycles decreased to 2.2 μm or less.

[0023] On the other hand, as shown in Figures 12(C), 13(A), and (C), the surface roughness Rz of the workpieces after processing, both immediately after starting to use the honing tools according to Examples 1, 2, and 4 and after 30 processing cycles, was 3.0 μm or higher, which was relatively high. From this, it was found that by forming four or more second grooves 121a and 122a in the guide sections 121 and 122, the accumulation of chips between the inner walls of workpieces W1, W2, ..., and W5 and the grinding section 13 during processing of each workpiece was suppressed, and the cleaning performance by the grinding fluid between the inner walls and the grinding section 13 was improved.

[0024] Furthermore, the change in the maximum current value supplied to the rotary drive unit 5 from immediately after the start of use of the honing tool to 30 processing cycles was compared. As shown in Figures 14(A) and (B), the maximum current value when using the honing tools according to Comparative Examples 1 and 2 remained at 4.5A or higher until 28 processing cycles. Also, as shown in Figure 15(B), the maximum current value when using the honing tool according to Example 3 remained between 3.8A and 4.8A. On the other hand, as shown in Figures 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 4.6A. From this, it can be seen that by forming four or more second grooves 121a and 122a in the guide sections 121 and 122, an excessive increase in friction between the inner walls of workpieces W1, W2, ..., and W5 and the grinding section 13 during processing of workpieces W1, W2, ..., and W5 is suppressed.

[0025] Furthermore, the changes in the amount of expansion of the grinding section 13 during honing were compared for each case from immediately after the start of use of the honing tool to 30 treatments. As shown in Figures 16(A) and (B), when the honing tools according to Comparative Examples 1 and 2 were used, the amount of expansion immediately after the start of use was relatively large, at 295 μm or more. Also, as shown in Figure 17(B), when the honing tool according to Example 3 was used, the amount of expansion immediately after the start of use was also relatively large, at approximately 305 μm. On the other hand, as shown in Figures 16(C), 17(A), and (C), when the honing tools according to Examples 1, 2, and 4 were used, the amount of expansion immediately after the start of use was less than 295 μm in all cases. From this, it can be seen that by forming four or more second grooves 121a and 122a in the guide sections 121 and 122, an excessive increase in friction between the inner walls of each workpiece W1, W2, ..., W5 and the grinding section 13 during machining of the workpieces W1, W2, ..., W5 is suppressed, especially immediately after the start of use of 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 sections 121 and 122 were set to be the same, we will describe the results of evaluating the fluidity of grinding oil when grinding oil was introduced into the hopper section with a transparent jig having a transparent cylindrical straight pipe section having an inner diameter approximately the same as the processed hole Wh of the workpieces W1, W2, ..., W5, and a hopper section continuously formed integrally at the vertically upper end of the straight pipe section, while the honing tools 10001, 1 were inserted into the straight pipe section of the transparent jig. First, after inserting the honing tools 10001, 1 into the straight pipe section, and without rotating the honing tools 10001, 1, grinding oil was continuously introduced into the hopper section at the same flow rate for 30 seconds, and the amount of grinding oil that flowed vertically downward from the straight pipe section, i.e., the amount of grinding fluid permeated, was compared. In this case, 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 according to Comparative Example 2 was 216.7 g, while in Examples 1 to 3 it was 235 g or more. This indicates that the formation of the first grooves 121b and 122b in the guide sections 121 and 122 increases the fluidity of the grinding oil. Furthermore, after inserting the honing tool 1 according to Example 2 into the straight pipe section, the amount of grinding oil that flowed vertically downward from the straight pipe section, i.e., the amount of grinding fluid permeated, was compared while the honing tool 1 was reciprocated and rotated along the Z-axis direction within the straight pipe section and grinding oil was continuously supplied to the hopper section at the same flow rate for 30 seconds. In this case, 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 the presence or absence of reciprocating movement and rotational drive in the Z-axis direction, and the difference in axial speed and rotational speed when reciprocating in the Z-axis direction.

[0031] Furthermore, Figures 18(A) to 21(B) show the process when the honing tool 1 according to Example 2, Example 1, Example 3, and Example 4 is inserted into the straight pipe section, grinding oil is poured into the hopper section, and then the honing tool 1 is reciprocated and rotated along the Z-axis direction within the straight pipe section. As shown in Figures 18(A) and (B), when the honing tool 1 according to Example 2 is used, it is observed that the grinding fluid flows within the first grooves 121b, 122b and the second grooves 121a, 122a. Also, as shown in Figures 19(A) and (B), when the honing tool 1 according to Example 1 is used, it is observed that the grinding fluid flows within the first grooves 121b, 122b and the second grooves 121a, 122a. Furthermore, as shown in Figures 20(A) and (B), even when using the honing tool 1 according to Example 3, it was observed that the grinding fluid was flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. Also, as shown in Figures 21(A) and (B), even when using the honing tool 1 according to Example 4, it was observed that the grinding fluid was flowing within the first grooves 121b, 122b and the second grooves 121a, 122a. In particular, in the case of the honing tool 1 according to Example 4, it was observed that the flow rate of grinding oil near the grinding section 13 increased. From these observations, it can be seen that when chips are present near the grinding section 13 of the honing tool 1, these chips can be discharged vertically downward along with the grinding oil, and in particular, the honing tool according to Example 4 has high performance in discharging chips vertically downward along with the grinding oil.

[0032] As described above, in the honing tool 1 according to this embodiment, guide portions 121 and 122 are provided on both sides of the slit 12a in the Z-axis direction of the tool body 12, so that when machining multiple workpieces W1, W2, ..., W5, it is possible to prevent the multiple workpieces W1, W2, ..., W5 from shifting relative to each other in the direction perpendicular to the cylindrical axis J1 direction, i.e., in the XY direction. Furthermore, since first grooves 121b, 122b and second grooves 121a, 122a are formed in the guide portions 121 and 122 of the tool body 12, when machining multiple workpieces W1, W2, ..., W5, the introduction of grinding fluid to the area around the slit 12a and the discharge of grinding fluid from the area around the slit 12a are promoted through the first grooves 121b, 122b and the second grooves 121a, 122a. Therefore, during the machining of multiple workpieces W1, W2, ..., W5, the accumulation of chips between the inner walls of each workpiece W1, W2, ..., W5 and the grinding section 13, as well as an excessive increase in friction between the inner walls and the grinding section 13, are suppressed. As a result, grinding defects on the inner walls of the workpieces W1, W2, ..., W5 can be suppressed. Consequently, the inner walls of each of the multiple workpieces W1, W2, ..., W5 can be ground simultaneously and with high precision.

[0033] Although embodiments of the present invention have been described above, the present invention is not limited to the configuration of the embodiments described above. For example, in the embodiments, the number of grooves in the first grooves 121b and 122b may be less than 3 or 5 or more. Also, the number of grooves in the second grooves 121a and 122a may be 5 or more.

[0034] Although embodiments and variations of the present invention have been described above, the present invention is not limited thereto. The present invention includes embodiments and variations that are appropriately combined, and those that are appropriately modified thereto. [Industrial applicability]

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

[0036] 1: Honing tool, 2: Rotary spindle, 3: Machine body, 4: Reciprocating drive unit, 5: Rotary drive unit, 6: Expansion drive unit, 11: Expansion rod, 11a, 13b: Tapered surface, 11b: Guide part, 11c: Movement limiting part, 12: Tool body, 12a: Slit, 12f: Stepped part, 13: Grinding part, 13a: Grinding surface, 20: Shank part, 100: Honing processing device, 121, 122: Guide part, 121a, 122a: Second groove, 121b, 122b: First groove, 131: Grinding wheel, 132: Grinding wheel holder, 171, 172: Biasing member, J0, J2, J10: Central axis, J1: Cylindrical axis, W1, W2, W3, W4, W5: Workpiece, Wa: Inner wall, Wh: Machined hole

Claims

1. A honing tool that is attached to the tip of the rotating spindle of a honing machine and hones the inner wall of the machining hole of each of a plurality of workpieces that are stacked so that the central axes of the machining holes coincide, A grinding section having a grinding surface and a first tapered surface on the opposite side of the grinding surface that is inclined with respect to the grinding surface, The tool body is long and cylindrical, and has a slit at one end in the direction of the cylinder axis through which the grinding portion is inserted, with the first tapered surface facing inward as it approaches the cylinder axis towards the end in the direction of the cylinder axis, and the other end in the direction of the cylinder axis is fixed to the rotating spindle. The tool comprises a rod-shaped extension rod having a second tapered surface that is inclined so as it approaches a first central axis along the longitudinal direction towards one end along the longitudinal direction, and an extension rod inserted inside the tool body such 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, which restrict the relative movement of the multiple workpieces in a direction perpendicular to the cylindrical axis direction during the honing of the multiple workpieces. The guide portion has a plurality of first grooves extending along the cylindrical axis direction in the side wall of the guide portion and communicating with the outer ends of both ends in the cylindrical axis direction of the guide portion, and a plurality of second grooves extending spirally around the cylindrical axis between the plurality of first grooves in the circumferential direction of the side wall around the cylindrical axis. Honing tool.

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

3. At the intersection of a virtual plane that includes the cylindrical shaft and passes through the portion of the side wall of the guide portion in which the second groove is formed, and a second central axis along the extending direction of the second groove, the angle between the extending direction of the second groove and the cylindrical shaft, when viewed from a direction along a virtual straight line perpendicular to the cylindrical shaft and passing through the intersection, is 15 degrees or more and 45 degrees or less. A honing tool according to claim 1 or 2.

4. The multiple second grooves are four or more in number. A honing tool according to claim 1 or 2.

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