Apparatus for shaping center holes in shaft members, and method for shaping center holes in shaft members

Abstract

To provide a center hole forming device of a shaft member which can inexpensively form a center hole of the shaft member without using dedicated equipment, and a center hole forming method of the shaft member.SOLUTION: A center hole forming device 20 of a shaft member 10 comprises a base 21 on which the shaft member 10 having a center hole at one end part 12 is arranged, a grindstone 26 for forming the center hole of the shaft member 10 which is arranged on the base 21, and a movable sensor for rotating the grindstone 26 around an axial line L2, and moving the grindstone 26 so as to make it close to and away from the center hole of the shaft member 10. The grindstone 26 and the shaft member 10 are arranged in a state where an axial line L2 of the grindstone 26 and an axial line L1 of the shaft member 10 are inclined at certain angles, and the movable center can move the grindstone 26 so that the grindstone 26 and the center hole of the shaft member 10 contact with each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a center hole shaping device for a shaft member and a center hole shaping method for a shaft member.

Background Art

[0002] Conventionally, a processing device and a processing method for processing a center hole at an end of a shaft member have been proposed (for example, see Patent Document 1).

[0003] In the above Patent Document 1, when manufacturing a shaft member such as a shaft of a CVT (Continuously Variable Transmission), a processing device and a processing method for processing (forming) a center hole at at least one of one end and the other end in the axial direction of the shaft member are described.

[0004] In the above Patent Document 1, when processing center holes at one end and the other end in the axial direction of a shaft member, with the shaft member held by a chuck, one end of the shaft member is cut by an end face cutting tool to form an end face, and a center hole is formed in this end face using a center hole drill. Further, in the above Patent Document 1, regarding the other end of the shaft member, end face cutting and center hole processing are also performed in the same manner as the one end.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Generally, when machining shaft-shaped parts, a center hole is machined at the end before machining the shaft itself. If heat treatment is then performed, heat treatment distortion can cause bending of the shaft or distortion of the center hole. Since the center hole also serves as a reference for subsequent machining, shaping of the center hole may be performed after heat treatment. Typically, the circumferential surface of the center hole of a shaft member is tapered, so a special grinding wheel with a tapered section is used during shaping. However, using a special grinding wheel during shaping increases costs and requires time-consuming dressing of the special grinding wheel, resulting in poor maintainability.

[0007] Furthermore, the precision of the reference center hole is extremely important for manufacturing high-precision shaft components. For this reason, it is conceivable to use specialized equipment such as a center hole grinding machine to shape the center hole, but this is expensive and has poor productivity, making it unsuitable for mass-produced parts such as those in automobiles.

[0008] The present invention was made to solve the above problems, and aims to provide a center hole shaping device for a shaft member and a center hole shaping method for a shaft member that can shape the center hole of the shaft member inexpensively without using specialized equipment. [Means for solving the problem]

[0009] To achieve the above objective, the present invention is configured as follows.

[0010] (1) The present invention relates to a center hole shaping apparatus for a shaft member, comprising: an installation section on which a shaft member having a center hole at its end is installed; a shaping member installed in the installation section for shaping the center hole of the shaft member; and a moving device that rotates the shaping member around its axis and moves the shaping member closer to and further away from the center hole of the shaft member, wherein the shaping member and the shaft member are arranged such that the axis of the shaping member and the axis of the shaft member are inclined at a first angle, and the moving device moves the shaping member so that the shaping member and the center hole of the shaft member come into contact.

[0011] According to the above configuration, since the axis of the shaping workpiece is inclined at a first angle with respect to the axis of the shaft member, the center hole of the shaft member can be shaped so that the center hole of the shaft member is inclined at a first angle with respect to the axis of the shaft member. Furthermore, according to the above configuration, since the shaping workpiece is moved in the axial direction of the shaping workpiece by the moving device while shaping is performed on the center hole of the shaft member, the center hole can be shaped while the shaping workpiece and the center hole of the shaft member are in contact at different positions. As a result, wear of the shaping workpiece at a certain position is suppressed, and the effects of wear on the shaping workpiece can be reduced. Thus, according to the above configuration, the center hole of the shaft member can be shaped inexpensively without using specialized equipment.

[0012] (2) In the center hole shaping apparatus for a shaft member according to the present invention, the shaft member is configured to be rotatable about an axis in the shaft member, and the rotational speed of the shaping member about the axis is preferably greater than the rotational speed of the shaft member about the axis. With this configuration, the shaping of the center hole in the shaft member can be performed quickly because the rotational speed of the shaping member is greater than the rotational speed of the shaft member.

[0013] (3) In the center hole shaping apparatus for a shaft member according to the present invention, it is preferable to further provide a holding member that holds the shaft member rotatably around its axis at a predetermined position in the axial direction of the shaft member. With this configuration, the shaft member is stably held by the holding member, so that it can be rotated while suppressing axial runout of the shaft member. As a result, the shaping of the center hole of the shaft member can be performed with high precision.

[0014] (4) In the center hole shaping apparatus for a shaft member according to the present invention, the shaping member comprises a shaft portion and a grinding wheel portion at the end of the shaft portion, and the grinding wheel portion is preferably formed with the same diameter along the axial direction of the shaft portion. With this configuration, the grinding wheel portion of the shaping member can be formed in a rod shape, and therefore, radial dimensional correction of the center hole of the shaft member can be easily performed simply by moving the shaping member radially relative to the center hole of the shaft member. Furthermore, since the grinding wheel portion of the shaping member is rod-shaped, the grinding wheel portion can be easily dressed.

[0015] (5) In the center hole shaping apparatus for a shaft member according to the present invention, the installation portion on which the shaft member is installed is positioned at a second angle with respect to the horizontal plane, and the shaping member is positioned such that the axis of the shaping member is perpendicular to the horizontal plane. With this configuration, the center hole of the shaft member can be shaped such that the circumferential surface portion constituting the center hole of the shaft member and the axis of the shaft member form a second angle.

[0016] (6) In the center hole shaping apparatus for a shaft member according to the present invention, the center hole of the shaft member has a tapered circumferential surface, the circumferential surface of the center hole of the shaft member is positioned at a third angle with respect to the axis of the shaft member, and the first angle formed by the axis of the shaping member and the axis of the shaft member is preferably greater than the third angle. With this configuration, when shaping is performed in the center hole of the shaft member, the shaping member comes into contact with the circumferential surface of the center hole, so that the circumferential surface of the center hole can be shaped at any angle.

[0017] (7) The present invention relates to a method for shaping a center hole in a shaft member, wherein a shaft member having a center hole at its end is installed in an installation section, and a shaping member for shaping the center hole is rotated around its axis and moved by a moving device to approach and move away from the center hole in the shaft member, characterized in that the shaping member and the shaft member are positioned such that the axis of the shaping member and the axis of the shaft member are inclined at a first angle, and the shaping member is moved by the moving device to bring the shaping member into contact with the center hole in the shaft member, thereby shaping the center hole.

[0018] According to the above configuration, since the axis of the shaping workpiece is inclined at a first angle with respect to the axis of the shaft member, the center hole of the shaft member can be shaped so that it is inclined at a first angle with respect to the axis of the shaft member. Furthermore, according to the above configuration, since the shaping workpiece is moved in the axial direction of the shaping workpiece by the moving device while shaping is performed on the center hole of the shaft member, the shaping workpiece and the center hole of the shaft member are processed while in contact at different positions. As a result, wear of the shaping workpiece at a certain position is suppressed, and the effects of wear on the shaping workpiece can be reduced. Thus, according to the above configuration, the center hole of the shaft member can be shaped inexpensively without using specialized equipment. [Effects of the Invention]

[0019] According to an aspect of the present invention, it is possible to provide a center hole shaping apparatus for a shaft member and a center hole shaping method for a shaft member that can shape the center hole of the shaft member inexpensively without using specialized equipment. [Brief explanation of the drawing]

[0020] [Figure 1] (a) is a diagram illustrating the centering of the shaft member according to this embodiment, and (b) is a diagram illustrating the clamping of the shaft member according to this embodiment. [Figure 2]This is a diagram for explaining the sizing process of the center hole of the shaft member according to this embodiment. [Figure 3] This is a diagram showing the state of approaching and separating the grinding wheel according to this embodiment with respect to the center hole of the shaft member. [Figure 4] This is a diagram showing the state of sizing the center hole of the shaft member with the grinding wheel according to this embodiment. [Figure 5] This is a diagram showing the state where a diameter-expanded portion is formed on the circumferential surface of the center hole of the shaft member according to this embodiment.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of a center hole sizing device for a shaft member and a center hole sizing method for a shaft member according to the present invention will be described with reference to the accompanying drawings. These drawings are schematic diagrams and are not necessarily drawn to an accurate scale. Also, in the drawings, similar components are denoted by the same reference numerals.

[0022] (Shaft member) Referring to FIGS. 1 and 3, the configuration of the shaft member according to this embodiment will be described. As an example of the shaft member, a shaft of a CVT (Continuously Variable Transmission) mounted on an automobile can be cited.

[0023] As shown in FIG. 1, the shaft member 10 includes a shaft portion 11 at its central portion. On one end portion 12 side of the shaft portion 11, a disk portion 13 that projects in a flange shape in a direction perpendicular to the axis L1 of the shaft member 10 is provided. On one surface of the disk portion 13, a tapered sheave surface 13a is formed. On the one end portion 12 side of the disk portion 13, a center hole 14 is formed. Inside the center hole 14, a tapered circumferential surface portion 14a (see FIG. 3) that constitutes the center hole 14 is formed. On the other end portion 15 side of the shaft portion 11, a spline portion 16 is formed. On the other end portion 15 side of the spline portion 16, a center hole (not shown) having a tapered circumferential surface is formed.

[0024] Generally, after machining the shaft member 10, such as by creating a center hole, it is placed in a heat treatment furnace and subjected to heat treatment such as carburizing and quenching to increase its surface hardness. However, heat treatment of the shaft member 10 causes distortion, so it is necessary to shape (correct) the circumferential surface 14a of the center hole 14 of the shaft member 10. Next, the configuration of the center hole shaping device 20 for shaping the circumferential surface 14a of the center hole 14 of the shaft member 10 will be described.

[0025] (Center hole shaping machine) Referring to Figures 1 and 2, the configuration of the center hole shaping apparatus according to this embodiment will be described. An example of a center hole shaping apparatus is a general machining center.

[0026] As shown in Figures 1 and 2, the center hole shaping device 20 is equipped with a base 21 that is installed on the ground or floor. The base 21 is an example of the "installation part" of the present invention. The base 21 is installed at an angle β (approximately 30° in this embodiment) with respect to the horizontal plane H (installation surface). A positioning part 22 is provided on the upper surface 21a of the base 21. The positioning part 22 is provided with a tapered part 22a that narrows upwards. When centering the shaft member 10, the center hole at the other end 15 of the shaft member 10 is configured to engage with the tapered part 22a of the positioning part 22.

[0027] A support column 23 is provided at the end of the base 21. The support column 23 is provided so as to extend in a direction perpendicular to the upper surface 21a of the base 21. A movable center 24 is provided on the support column 23 via rails, sliders, etc. (not shown). The movable center 24 is an example of a "moving device" of the present invention. The movable center 24 is also movable vertically along the surface of the support column 23 (along the direction in which it extends). Furthermore, a shaft member 10 is positioned between the movable center 24 and the base 21, and the movable center 24 is movable to move closer to and away from the shaft member 10.

[0028] The movable center 24 is provided with a positioning portion 25. The positioning portion 25 is provided with a tapered portion 25a that narrows toward the base 21. When centering the shaft member 10, the tapered portion 25a of the positioning portion 25 is configured to engage with the center hole 14 at one end 12 of the shaft member 10.

[0029] As shown in Figure 2, the movable center 24 holds a grinding wheel 26 for shaping the circumferential surface 14a of the center hole 14 of the shaft member 10. The grinding wheel 26 is an example of a "shaping member" of the present invention. The grinding wheel 26 is positioned so that its axis L2 is perpendicular to the horizontal plane H.

[0030] Furthermore, the grinding wheel 26 comprises a shaft portion 261 and a grinding wheel portion 262 on which abrasive grains are provided on a part of the shaft portion 261. The grinding wheel portion 262 comprises a straight portion 262a and a tapered portion 262b. The straight portion 262a is formed with the same diameter along the axis L2 direction of the grinding wheel 26.

[0031] The grinding wheel 26 is configured to move toward and away from the circumferential surface 14a of the center hole 14 of the shaft portion 261 by means of a movable center 24. Specifically, the grinding wheel 26 is configured to move toward and away from the circumferential surface 14a of the center hole 14 of the shaft member 10 when the axis L2 of the grinding wheel 26 and the axis L1 of the shaft member 10 are inclined at an angle α (approximately 30° in this embodiment).

[0032] Furthermore, the grinding wheel 26 is configured to be rotatable around its axis L2. Specifically, the rotational speed of the grinding wheel 26 around axis L2 is configured to be greater than the rotational speed of the shaft member 10 around axis L1, which will be described later. Also, when the grinding wheel 26 is rotating, the straight portion 262a of the grinding wheel portion 262 comes into contact with the circumferential surface portion 14a of the center hole 14 of the shaft member 10, thereby grinding and shaping the circumferential surface portion 14a of the center hole 14.

[0033] A clamping device 27 is provided between the base 21 and the movable center 24. The clamping device 27 is an example of the "holding member" of the present invention. The clamping device 27 is connected to the support column 23 via a connecting member or the like (not shown). The clamping device 27 is provided to hold and release the shaft member 10 from the base 21 and the support column 23. The clamping device 27 is configured to rotate freely around the axis L1 while holding the shaft member 10. The clamping device 27 may also be configured to clamp the shaft member 10 from opposing directions, or to be a cylindrical configuration that clamps the entire circumference of the shaft member 10, and the device configuration can be selected as appropriate.

[0034] (Method for shaping the center hole) Next, with reference to Figures 1 to 5, the method for shaping a center hole according to this embodiment will be described. In this embodiment, the method for shaping the circumferential surface portion 14a of the center hole 14 formed at one end portion 12 of the shaft member 10 will be described.

[0035] First, as shown in Figure 1(a), a center hole (not shown) formed at the other end 15 of the shaft member 10 is placed against the tapered portion 22a of the positioning portion 22 provided on the upper surface 21a of the base 21. This temporarily places the shaft member 10 on the base 21. Next, a tapered portion 25a of the positioning portion 25 provided on the movable center 24 is placed against the center hole 14 formed at one end 12 of the shaft member 10. Then, the positioning portion 25 on the movable center 24 is advanced (pressed) against the center hole 14 of the shaft member 10, thereby centering the shaft member 10.

[0036] Next, as shown in Figure 1(b), the shaft member 10 is held at a predetermined position (in this embodiment, near the spline portion 16) by the clamping device 27. At this time, the shaft member 10 is rotatable around the axis L1 of the shaft member 10 while being held by the clamping device 27.

[0037] As shown in Figures 2 and 3, the shaft member 10 begins to rotate around axis L1 while being held by the clamping device 27. The rotation direction of the shaft member 10 can be either clockwise or counterclockwise. Next, the grinding wheel 26, held by the movable center 24, rotates around axis L2 and approaches the center hole 14 of the shaft member 10. The rotation direction of the grinding wheel 26 can be either clockwise or counterclockwise, but the rotation direction is appropriately selected depending on the rotation direction of the shaft member 10. Furthermore, the rotational speed of the grinding wheel 26 around axis L2 is greater than the rotational speed of the shaft member 10 around axis L1.

[0038] As shown in Figure 3, the grinding wheel 26 is positioned close to the center hole 14 of the shaft member 10 with its axis L2 and the axis L1 of the shaft member 10 inclined at an angle α (approximately 30° in this embodiment). At this time, the angle α between the axis L1 of the shaft member 10 and the axis L2 of the grinding wheel 26 is greater than the angle γ between the axis L1 of the shaft member 10 and the circumferential surface 14a of the center hole 14.

[0039] As shown in Figure 4, with the straight portion 262a of the grinding wheel portion 262 of the grinding wheel 26 in contact with the circumferential surface portion 14a of the center hole 14 of the shaft member 10, the straight portion 262a of the grinding wheel portion 262 of the grinding wheel 26 rotates around the axis L2 and moves back and forth along the direction of the axis L2. As a result, as shown in Figure 5, the circumferential surface portion 14a of the center hole 14 of the shaft member 10 is ground (dashed line shown in Figure 5), and an enlarged diameter portion 14b with a larger diameter than the circumferential surface portion 14a of the center hole 14 of the shaft member 10 is formed. In addition, the machined surface of the enlarged diameter portion 14b of the center hole 14 is shaped to be parallel to the axis L2 on the grinding wheel 26. This completes the shaping process of the center hole 14 of the shaft member 10.

[0040] According to the embodiment described above, the following effects (1) to (6) can be obtained.

[0041] (1) In the shaft member center hole shaping apparatus and shaft member center hole shaping method according to this embodiment, the shaft member 10 and the grinding wheel 26 are arranged so that the axis L1 of the shaft member 10 and the axis L2 of the grinding wheel 26 are inclined at an angle α, and the grinding wheel 26 is moved by the movable center 24 so that the center hole 14 of the shaft member 10 and the grinding wheel 26 come into contact. According to the above embodiment, since the axis L1 of the shaft member 10 is inclined at an angle α (a certain angle) with respect to the axis L2 of the grinding wheel 26, the circumferential surface 14a of the center hole 14 of the shaft member 10 can be shaped so that the circumferential surface 14a of the center hole 14 of the shaft member 10 is inclined at an angle α with respect to the axis L1 of the shaft member 10. Furthermore, according to the above embodiment, since the grinding wheel 26 is moved in the axial direction L2 by the movable center 24 while shaping the center hole 14 of the shaft member 10, the center hole 14 can be machined while the center hole 14 of the shaft member 10 and the grinding wheel 26 are in contact at different positions. As a result, wear of the grinding wheel 26 at a fixed position is suppressed, and the effect of wear of the grinding wheel 26 can be reduced. Thus, according to the above embodiment, the circumferential surface portion 14a of the center hole 14 of the shaft member 10 can be shaped inexpensively without using dedicated equipment.

[0042] (2) In the center hole shaping apparatus for the shaft member according to this embodiment, the rotational speed of the grinding wheel 26 around the axis L2 is made greater than the rotational speed of the shaft member 10 around the axis L1. As a result, the shaping of the center hole 14 of the shaft member 10 can be performed more quickly by making the rotational speed of the grinding wheel 26 greater than the rotational speed of the shaft member 10.

[0043] (3) In the shaft member center hole shaping apparatus according to this embodiment, the shaft member 10 is held rotatably around the axis L1 by a clamp member 27 at a predetermined position in the direction of the axis L1 on the shaft member 10. As a result, the shaft member 10 is stably held by the clamp member 27, and can be rotated while suppressing axial runout of the shaft member 10. Therefore, the shaping of the center hole 14 of the shaft member 10 can be performed with high precision.

[0044] (4) In the center hole shaping apparatus for the shaft member according to this embodiment, the grinding wheel portion 262 of the grinding wheel 26 is formed with the same diameter along the axis L2 direction. This makes it possible to form the grinding wheel portion 262 of the grinding wheel 26 in a rod shape. Therefore, by simply moving the grinding wheel 26 radially relative to the center hole 14 of the shaft member 10, radial dimensional correction of the circumferential surface portion 14a of the center hole 14 of the shaft member 10 can be easily performed. In addition, since the grinding wheel portion 262 of the grinding wheel 26 is rod-shaped, the grinding wheel portion 262 can be easily dressed.

[0045] (5) In the center hole shaping apparatus for a shaft member according to this embodiment, the base 21 on which the shaft member 10 is installed is positioned at an angle β with respect to the horizontal plane H, and the grinding wheel 26 is positioned so that the axis of the grinding wheel 26 is perpendicular to the horizontal plane H. As a result, the center hole 14 of the shaft member 10 can be shaped so that the circumferential surface portion 14a constituting the center hole 14 of the shaft member 10 and the axis L1 of the shaft member 10 form an angle β.

[0046] (6) In the center hole shaping apparatus for the shaft member according to this embodiment, the angle α between the axis L1 of the shaft member 10 and the axis L2 of the grinding wheel 26 is made larger than the angle γ between the axis L1 of the shaft member 10 and the circumferential surface portion 14a of the center hole 14 of the shaft member 10. As a result, when shaping is performed on the circumferential surface portion 14a of the center hole 14 of the shaft member 10, the straight portion 262a of the grinding wheel portion 262 of the grinding wheel 26 comes into contact with the circumferential surface portion 14a of the center hole 14, so that the circumferential surface portion 14a of the center hole 14 can be shaped at any angle.

[0047] The above embodiment can also be configured with the following modifications.

[0048] In the above embodiment, a CVT shaft was shown as an example of a shaft member, but the present invention is not limited thereto. The present invention can be applied to engine crankshafts and shaft members used in general machinery, as long as it is possible to shape the center hole of the shaft member.

[0049] In the above embodiment, an example was shown in which the axis of the shaft member and the axis of the grinding wheel are inclined at an angle of approximately 30°, but the present invention is not limited to this. In the present invention, it is preferable to set the inclination angle between the axis of the shaft member and the axis of the grinding wheel according to the magnitude of the angle between the axis of the shaft member and the circumferential surface of the center hole of the shaft member.

[0050] In the above embodiment, an example was shown in which the rotational speed of the grinding wheel around the axis is greater than the rotational speed of the shaft member around the axis, but the present invention is not limited thereto. In the present invention, if the processing speed and processing accuracy of the shaping process in the center hole of the shaft member are to be improved, it is preferable to configure the grinding wheel around the axis to be less than the rotational speed of the shaft member around the axis.

[0051] In the above embodiment, an example was shown in which the vicinity of the spline portion of the shaft member is held by a clamping device, but the present invention is not limited thereto. In the present invention, it is preferable to hold a portion other than the vicinity of the spline portion with the clamping device, as long as it is possible to stably hold the shaft member during rotation and shaping.

[0052] The embodiments described above are all illustrative examples of the application of the present invention, and it goes without saying that any other embodiments within the scope of the claims are also included in the technical scope of the invention. [Explanation of Symbols]

[0053] 10: Shaft member 12: One end (end) 14: Center hole 14a: Peripheral part 20: Center hole shaping machine 21: Base (installation part) 24: Movable center (moving device) 26: Grinding wheel (shaping and processing component) 27: Clamp member (holding member) 261: Shaft 262: Sharpening Stone Section H: horizontal plane L1: Axis line L2: Axis α: First angle β: Second angle γ: Third angle

Claims

1. An installation section on which a heat-treated shaft member having a center hole at its end is installed, A shaping member for shaping the center hole of the shaft member installed in the aforementioned installation section, A moving device that rotates the shaping member around its axis and moves the shaping member along a support column provided in a direction perpendicular to the installation portion so as to move it closer to and further away from the center hole of the axis member, The system includes a holding member provided between the installation portion and the moving device, which holds the shaft member so that it can rotate around its axis, The shaping member and the shaft member are arranged such that the axis of the shaping member and the axis of the shaft member are inclined at a first angle. The moving device moves the shaping member so that it comes into contact with the center hole of the shaft member. A center hole shaping apparatus for a shaft member, characterized in that the mounting portion and the support column are provided at an inclination with respect to the mounting surface on which the mounting portion is placed.

2. The shaft member is configured to be rotatable about the axis of the shaft member, The center hole shaping apparatus for a shaft member according to claim 1, characterized in that the rotational speed around the axis of the shaping workpiece is greater than the rotational speed around the axis of the shaft member.

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