Rotating member

Abstract

An relief-shaped part (4) that can be detected by a Hall element sensor is formed on the outer peripheral surface of a rotating member (1). The relief-shaped part (4) has a plurality of protrusions (6) and a plurality of recesses (7) formed between neighboring protrusions (6). The relief-shaped part (4) comprises: one end surface side section (9) positioned on the one end surface (8) side of the rotating member (1); and an other end surface side section (11) positioned on the other end surface (10) side of the rotating member (1). The one end surface side section (9) is for reading the rotational speed of the rotating member (1) by using the Hall element sensor, and is formed such that the intervals between opposing side surfaces (12) of the neighboring protrusions (6) are uniform. The other end surface side section (11) has a smaller cutting amount than the one end surface side section (9), and is formed such that the distance between the opposing side surfaces (12) of the neighboring protrusions (6) narrows toward the other end surface (10) side of the rotating member (1).

Description

Rotating parts

[0001] The present invention relates to a rotating member whose rotation speed is detected by a Hall element sensor.

[0002] For example, Patent Document 1 discloses a gear cutting method for cutting a tapered gear into a workpiece using a hob (hob cutter).

[0003] Patent Document 1 discloses a gear machining method in which gear cutting is performed using a hob over the entire axial length of a workpiece to be formed into a gear.

[0004] Here, when forming a concave-convex shape for sensor detection using a hob, it is sufficient that the concave-convex shape is formed in a range that can be detected by the sensor.

[0005] However, if gear cutting is performed using a hob over the entire axial length of the workpiece, the gear cutting using the hob may be performed more than necessary, which may increase the processing time using the hob. Furthermore, Patent Document 1 does not take into consideration gear cutting of uneven shapes that are easy for a sensor to detect.

[0006] In other words, when providing a workpiece with an uneven shape that can be detected by a sensor, there is room for further improvement in terms of shortening the processing time and making it easier to detect by the sensor.

[0007] Japanese Patent Application Publication No. 59-7519

[0008] The rotating member of the present invention has an uneven portion formed on its outer surface that can be detected by a Hall element sensor, the uneven portion having a plurality of convex portions protruding radially and a plurality of concave portions formed between adjacent convex portions, the uneven portion comprising a one end face side portion located on one end face side of the rotating member, and an other end face side portion that is continuous with the one end face side portion along the rotational axis direction of the rotating member and is located on the other end face side of the rotating member, the one end face side portion being a portion that reads the rotation speed of the rotating member with the Hall element sensor, and is formed so that the spacing between the opposing side surfaces of adjacent convex portions is constant along the rotational axis direction of the rotating member, and the other end face side portion being a portion that has a smaller amount of cutting than the one end face side portion, and is formed so that the spacing between the opposing side surfaces of adjacent convex portions becomes narrower towards the other end face side of the rotating member.

[0009] The rotating member of the present invention has a smaller cutting amount on the other end surface side of the uneven portion than on one end surface side of the uneven portion, which is the part where the rotation speed is read by the Hall element sensor. Therefore, the processing time for the uneven portion can be shortened overall, and the cost of the rotating member can be reduced while ensuring the sensing performance of the Hall element sensor.

[0010] FIG. 1 is an explanatory diagram schematically showing a state in which a rotating member according to a first embodiment of the present invention is machined with a hob cutter. FIG. 2 is an explanatory diagram schematically showing an example of a concave-convex portion of a rotating member according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram schematically showing an example of a concave-convex portion of a rotating member according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram schematically showing a state in which a rotating member according to a second embodiment of the present invention is machined with a hob cutter. FIG. 5 is an explanatory diagram schematically showing an example of a concave-convex portion of a rotating member according to the present invention. FIG. 6 is an explanatory diagram schematically showing an example of a concave-convex portion of a rotating member according to the present invention.

[0011] 1 is a schematic diagram illustrating a state in which a rotary member 1 according to a first embodiment of the present invention is machined by a hob cutter 2.

[0012] The rotating member 1 is a disk-shaped flywheel attached to, for example, the crankshaft of an internal combustion engine, and is attached with its center of gravity located on a rotation axis R1 along the axial direction to a rotatable shaft member (not shown, for example, a crankshaft).

[0013] The rotating member 1 has an uneven portion 4 formed on an outer peripheral surface 3 in the radial direction. The uneven portion 4 is formed by cutting with a hob cutter 2 along the circumferential direction of the outer peripheral surface 3 so as to be continuous over the entire circumference of the outer peripheral surface 3. Note that the uneven portion 4 may be formed by a method other than cutting with a hob cutter 2.

[0014] The hob cutter 2 has a plurality of teeth 5 on its outer circumferential surface. The plurality of teeth 5 of the hob cutter 2 are arranged discontinuously in a spiral shape.

[0015] The uneven portion 4 is formed by rotating the rotating member 1 around the rotation axis R1 of the rotating member 1 and rotating the hob cutter 2 around the rotation axis R2 of the hob cutter 2 while moving it along a feed direction parallel to the rotation axis R1 of the rotating member 1.

[0016] The uneven portion 4 has a plurality of projections 6 projecting in the radial direction of the rotary member 1 and a plurality of recesses 7 formed between adjacent projections 6 , 6 .

[0017] The uneven portion 4 is composed of a one-end surface side portion 9 located on the one end surface 8 side of the rotating member 1 where cutting by the hob cutter 2 begins in the axial direction of the rotation axis R1 of the rotating member 1, and an other-end surface side portion 11 that is continuous with the one-end surface side portion 9 along the axial direction of the rotation axis R1 of the rotating member 1 and is located on the other end surface 10 side of the rotating member 1.

[0018] 2A and 2B are explanatory diagrams schematically illustrating an example of the concave-convex portion 4 of the rotating member 1 in the first embodiment of the present invention. Fig. 2A is a plan view of the concave-convex portion 4. Fig. 2B is a side view of the concave-convex portion 4 as viewed from one end surface 8. Fig. 2C is a cross-sectional view of the concave-convex portion 4 taken along the rotation axis R1.

[0019] 2A, the one end surface side portion 9 is a portion where the rotation speed of the rotating member 1 is read by a Hall element sensor (not shown) such as a crank angle sensor, and is a portion where the feed amount of the hob cutter 2 is sufficient and cutting by the hob cutter 2 has been completed. In other words, the one end surface side portion 9 is a range where the uneven shape can be detected by the Hall element sensor.

[0020] The one end surface portion 9 is formed so that the interval (distance) between the opposing side surfaces 12 of adjacent convex portions 6 in the circumferential direction of the rotating member 1 is constant along the direction of the rotation axis R1 of the rotating member 1. As shown in Figure 2(b), the one end surface portion 9 is formed so that the bottom surfaces 13 of the concave portions 7 have a constant depth along the direction of the rotation axis R1 of the rotating member 1. The Hall element sensor detects the uneven shape of the concave-convex portion 4 of the rotating member 1 to detect the number of rotations of the rotating member 1.

[0021] 2A, the other end surface side portion 11 is a portion where the cutting amount by the hob cutter 2 is smaller than that by the one end surface side portion 9. In other words, the other end surface side portion 11 is a portion where the feed amount of the hob cutter 2 is insufficient and cutting by the hob cutter 2 has not been completed. In other words, the other end surface side portion 11 is a portion where the cutting amount by the hob cutter is smaller than that by the one end surface side portion 9.

[0022] The other end surface portion 11 is formed so that the interval (distance) between the opposing side surfaces 12 of adjacent protrusions 6 in the circumferential direction of the rotating member 1 becomes narrower toward the other end surface 10 of the rotating member 1.

[0023] 2(b), the other end surface side portion 11 is formed so that the bottom surface 13 of the recess 7 becomes shallower as it approaches the other end surface 10 of the rotating member 1. Furthermore, the protrusions 6 of the uneven portion 4 are formed so that the width along the circumferential direction of the rotating member 1 becomes wider as it approaches the other end surface 10 in the other end surface side portion 11.

[0024] The convex portion 6 of the uneven portion 4 is formed so that the inclination angle α, which is the angle between the side surface 12 facing the adjacent convex portion 6 and the bottom surface 13 of the recess 7, is greater than 90°, within the range in which the detection accuracy of the uneven portion 4 by the Hall element sensor is guaranteed.

[0025] The recess 7 of the uneven portion 4 has a tapered shape in a planar view up to the end on the other end face 10 side in the axial direction of the rotation axis R1, and is formed so that the other end face side portion 11 has a wedge shape (isosceles triangle shape) in a planar view.

[0026] The uneven portion 4 is formed so that as the inclination angle α increases, the spacing (distance) between the opposing side surfaces 12 of adjacent convex portions 6 on the other end face side portion 11 becomes increasingly narrower along the axial direction of the rotation axis R1 of the rotating member 1 toward the other end face 10 of the rotating member 1.

[0027] In other words, as shown in Figure 3, as the inclination angle α of the uneven portion 4 increases, the spacing (distance) between the opposing side surfaces 12 of adjacent convex portions 6 on the other end face side portion 11 gradually narrows along the axial direction of the rotation axis R1 of the rotating member 1.

[0028] Figure 3 is an explanatory diagram schematically showing an example of the concave-convex portion 4 of the rotating member 1 in the first embodiment of the present invention, showing a case where the inclination angle α is larger than that shown in Figure 2 described above. Figure 3(a) is a plan view of the concave-convex portion 4. Figure 3(b) is a side view of the concave-convex portion 4 as viewed from one end surface 8. Figure 3(c) is a cross-sectional view of the concave-convex portion 4 taken along the rotation axis R1.

[0029] It should be noted that the smaller the inclination angle α, the more cutting time is required for the uneven portion 4 because the amount of cutting required by the hob cutter 2 increases. However, as the inclination angle α decreases and approaches 90°, it becomes easier for the Hall element sensor to detect the uneven shape.

[0030] The length of the one end surface side portion 9 of the uneven portion 4 along the rotation axis R1 of the rotating member 1 is set so as to ensure the detection accuracy of the uneven portion 4 by the Hall element sensor.

[0031] The length of the concave-convex portion 4 along the rotation axis R1 of the rotary member 1 of the one end surface side portion 9 is set so that the center of the Hall element sensor faces the one end surface side portion 9.

[0032] The length of the uneven portion 4 along the rotation axis R1 of the rotating member 1 of the one end face side portion 9 is set so that the center of the Hall element sensor faces the central portion along the rotation axis R1 of the rotating member 1 of the one end face side portion 9.

[0033] In addition, as the cross-sectional shape of the blade 5 of the hob cutter 2 approaches a rectangle, the angle of the side surface 12 of the convex portion 6 with respect to the bottom surface 13 of the concave portion 7 approaches a perpendicular angle, and the cross-sectional shape of the convex portion 6 approaches a rectangle. Furthermore, when the cross-sectional shape of the blade 5 of the hob cutter 2 is a trapezoid, the inclination angle α between the side surface 12 of the convex portion 6 and the bottom surface 13 of the concave portion 7 decreases as the inclination of the hypotenuse of the trapezoid decreases (when the tip of the blade 5 is the upper base of the trapezoid, the angle between the lower base of the trapezoid and the hypotenuse decreases), and the cross-sectional shape of the convex portion 6 becomes a trapezoid with a smaller inclination of the hypotenuse (isosceles trapezoid).

[0034] When the feed rate of the hob cutter 2 along the axial direction of the rotation axis R1 of the rotating member 1 is sufficiently large, the center of rotation of the hob cutter 2 passes through the rotating member 1 in the axial direction of the rotation axis R1 of the rotating member 1, and the spacing (distance) between the opposing side surfaces 12 of adjacent convex portions 6 of the uneven shape portion 4 becomes constant over the entire length of the rotating member 1 in the axial direction of the rotation axis R1.

[0035] When the feed amount of the hob cutter 2 along the axial direction of the rotation axis R1 of the rotating member 1 is small, the center of rotation of the hob cutter 2 does not pass through the rotating member 1 in the axial direction of the rotation axis R1 of the rotating member 1, so the uneven portion 4 has one end face side portion 9 where the spacing (distance) between the opposing side surfaces 12 of adjacent convex portions 6 is constant, and the other end face side portion 11 where the spacing (distance) between the opposing side surfaces 12 of adjacent convex portions 6 becomes narrower toward the other end face 10 of the rotating member 1.

[0036] In other words, by stopping the feed of the rotating member 1 along the axial direction of the rotation axis R1 while the hob cutter 2 is cutting the rotating member 1, the uneven portion 4 can have one end face side portion 9 and the other end face side portion 11.

[0037] The uneven portion 4 of the rotating member 1 is formed so that the interval (distance) between the opposing side surfaces 12 of adjacent convex portions 6 is constant within the range required for detection of the uneven shape by the Hall element sensor along the direction of the rotation axis R1 of the rotating member 1. In other words, the rotating member 1 is cut by the hob cutter 2 within the required range, and when cutting within the required range is completed, cutting of the rotating member 1 by the hob cutter 2 is stopped midway.

[0038] The machining cost of the rotating member 1 is proportional to the machining time by the hob cutter 2. According to the present invention, the cutting time of the rotating member 1 by the hob cutter 2 can be shortened (reduced), thereby reducing the cost of the rotating member 1. In other words, according to the present invention, the amount of cutting of the other end surface side portion 11 of the concave-convex portion 4 can be made less than the amount of cutting of the one end surface side portion 9 of the concave-convex portion 4, which is the portion where the rotation speed is read by the Hall element sensor. Therefore, the machining time of the concave-convex portion 4 can be shortened overall, and the cost of the rotating member 1 can be reduced while ensuring the sensing performance of the Hall element sensor.

[0039] The rotating member 1 is formed so that the width of the convex portion 6 along the circumferential direction of the rotating member 1 is constant at one end face side portion 9 of the uneven portion 4, thereby improving the detection accuracy of the uneven shape by the above-mentioned Hall element sensor.

[0040] The cross-sectional shape of the convex portion 6 of the rotating member 1 is an isosceles trapezoid in which the upper base at the tip side is shorter than the lower base on the rotation axis R1 side of the rotating member 1, and the amount of cutting by the hob cutter 2 when forming the uneven shaped portion 4 is smaller than when the cross-sectional shape of the convex portion 6 is rectangular and the angle between the side surface 12 of the convex portion 6 and the bottom surface 13 of the recess 7 is 90°, so the processing time is shorter and manufacturing costs can be reduced.

[0041] The detection accuracy of the Hall element sensor for the uneven portion 4 improves the closer the side surface 12 of the convex portion 6 is to being perpendicular to the bottom surface 13 of the concave portion 7, and the longer the distance from the tip surface (tooth tip) 14 of the convex portion 6, which is the tooth tip of the uneven portion 4, to the bottom surface 13 of the concave portion 7, which is the tooth bottom of the uneven portion 4.

[0042] Therefore, the length of the one end face side portion 9 along the axial direction of the rotation axis R1 of the rotating member 1 is set so as to ensure the detection accuracy of the uneven shape portion 4 by the Hall element sensor, and by shortening the cutting time by the hob cutter 2 while ensuring the detection accuracy of the Hall element sensor, it is possible to achieve both quality and cost reduction of the rotating member 1.

[0043] Another embodiment of the present invention will be described below, in which the same components as those in the above-described embodiment are designated by the same reference numerals and redundant description will be omitted.

[0044] A second embodiment of the present invention will be described with reference to Figures 4 and 5. Figure 4 is an explanatory diagram schematically showing a state in which a rotating member 21 according to the second embodiment of the present invention is machined by a hob cutter 2. Figure 5 is an explanatory diagram schematically showing an example of the concave-convex portion 4 of the rotating member 21 in the second embodiment of the present invention. Figure 5(a) is a plan view of the concave-convex portion 4. Figure 5(b) is a side view of the concave-convex portion 4 as viewed from one end surface 8. Figure 5(c) is a cross-sectional view of the concave-convex portion 4 taken along the rotation axis R1.

[0045] The rotating member 21 of the second embodiment has substantially the same configuration as the rotating member 1 of the first embodiment described above, but the convex portions 6 of the concave-convex portion 4 are formed so that the cross section is a trapezoid that is close to a rectangle, as shown in Figures 4 and 5. Furthermore, in the rotating member 21 of the second embodiment, the concave portions 7 of the concave-convex portion 4 are formed so that the end portion on the other end face 10 side in the direction of the rotation axis R1 in plan view is cut off along the circumferential direction of the rotating member 1, and the other end face side portion 11 is formed so that it has a trapezoidal shape (isosceles trapezoidal shape) in plan view.

[0046] When the uneven portion 4 is formed by cutting with a hob cutter 2 having a blade 5 with a trapezoidal cross-sectional shape that is close to a rectangle, the convex portion 6 in the one end surface side portion 9 has a trapezoidal cross-sectional shape that is close to a rectangle. Furthermore, as the cross-sectional shape of the blade 5 of the hob cutter 2 approaches a rectangle from a trapezoidal shape, the tapered shape of the uneven portion 4 along the rotation axis R1 of the rotating member 21 in the other end surface side portion 11 is lessened.

[0047] The rotary member 21 of the second embodiment can achieve substantially the same effects as the rotary member 1 of the first embodiment described above.

[0048] Furthermore, in the rotary member 21 of the second embodiment, the tapered shape of the recess 7 in plan view can be less pronounced compared to the rotary member 1 of the first embodiment described above.

[0049] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

[0050] For example, the rotating members 1 and 21 of the above-described embodiments may be formed so that the bottom surfaces 13 of the recesses 7 of the uneven portion 4 are shallower, as long as the sensing performance of the Hall element sensor is not affected. In other words, the uneven portion 4 may be formed so that the distance from the tip surfaces (tooth tips) of the protrusions 6 to the bottom surfaces (tooth bottoms) 13 of the recesses 7 becomes shorter as the performance of the Hall element sensor becomes higher.

[0051] In the rotating members 1 and 21, the recesses 7 are formed to be shallower as the detection performance of the Hall element sensor increases, thereby reducing the amount of cutting required for the recesses 7, as shown in FIGS. 6 and 7 . FIGS. 6 and 7 are explanatory diagrams schematically illustrating an example of the concave-convex portion 4 of the rotating member 1 according to the present invention. FIG. 6 shows a case where the bottom surface 13 of the recesses 7 is shallow, and FIG. 7 shows a case where the bottom surface 13 of the recesses 7 is deeper than that shown in FIG. 6 . FIGS. 6 and 7 are explanatory diagrams schematically illustrating an example of the concave-convex portion 4 of the rotating member 1. FIGS. 6( a) and 7( a) are plan views of the concave-convex portion 4. FIGS. 6( b) and 7( b) are side views of the concave-convex portion 4 as viewed from one end surface 8. FIGS. 6( c) and 7( c) are cross-sectional views of the concave-convex portion 4 taken along the rotation axis R1.

[0052] By forming the rotating members 1, 21 so that the depth of the bottom surface 13 of the recess 7 becomes shallower as the detection performance of the Hall element sensor becomes higher, the processing time by the hob cutter 2 can be shortened and costs can be reduced.

[0053] For example, in the rotating members 1 and 21 of the above-described embodiments, when the shaft member is a crankshaft, one end face 8 of the rotating members 1 and 21 may be the end face that is located on the internal combustion engine side when the rotating member 1 is attached to the shaft member.

[0054] When the rotating members 1, 21 are attached to the shaft member, the further away from the internal combustion engine in the axial direction of the shaft member the more likely they are to whirl and tilt.

[0055] Therefore, by forming the uneven portion 4 on the engine side of the rotating members 1, 21, which is less affected by tilting due to whirling, it is possible to prevent deterioration in the detection accuracy of the uneven portion 4 by the Hall element sensor.

[0056] For example, the rotary members 1 and 21 of the above-described embodiments may have the concave-convex portion 4 formed by a method other than cutting using the hob cutter 2 .

[0057] For example, the rotating members 1 and 21 in the above-described embodiments may be drive plates.

Claims

1. A disc-shaped rotating member attached to a rotatable shaft member, having an uneven shape portion on the outer peripheral surface that can be detected by a Hall element sensor, the uneven shape portion having a plurality of convex portions protruding in the radial direction and a plurality of concave portions formed between adjacent convex portions, the uneven shape portion consisting of an end face side portion located on one end face side of the rotating member and an other end face side portion that is continuous along the axial direction of the rotation axis of the rotating member and is located on the other end face side of the rotating member, the end face side portion being a portion for reading the rotational speed of the rotating member by the Hall element sensor and being formed such that the distance between the opposing side surfaces of adjacent convex portions is constant along the axial direction of the rotation axis of the rotating member, and the other end face side portion being a portion with less cutting amount compared to the end face side portion and being formed such that the distance between the opposing side surfaces of adjacent convex portions becomes narrower toward the other end face side of the rotating member.

2. The rotating member according to claim 1, wherein the convex portions are formed such that the width along the circumferential direction of the rotating member is constant in the end face side portion.

3. The rotating member according to claim 1 or 2, wherein the convex portions are formed at an inclination angle, which is the angle formed between the side surface and the bottom surface of the concave portion, greater than 90°.

4. In the uneven shape portion, the distance between the opposing side surfaces of adjacent convex portions in the other end face side portion becomes rapidly narrower toward the other end face side of the rotating member as the inclination angle increases, and the length of the end face side portion along the axial direction of the rotation axis of the rotating member is set to ensure the detection accuracy of the uneven shape portion by the Hall element sensor. The rotating member according to claim 3.

5. The rotating member according to claim 4, wherein the length of the end face side portion along the axial direction of the rotation axis of the rotating member is set such that the center of the Hall element sensor faces the end face side portion.

6. The rotating member according to claim 5, wherein the length of the end face side portion along the axial direction of the rotation axis of the rotating member is set such that the center of the Hall element sensor faces the central portion of the end face side portion along the axial direction of the rotation axis of the rotating member.

7. The rotating member according to claim 1, wherein the uneven shape portion is formed such that the distance from the tip surface of the convex portion to the bottom surface of the concave portion becomes shorter as the performance of the Hall element sensor is higher.

8. The rotating member according to claim 1, wherein the concavo-convex shaped portion is formed by being cut with a hob cutter having a blade in a trapezoidal shape whose cross-sectional shape is close to a rectangle.

9. The rotating member according to claim 1, wherein the convex portion is formed so as to be a trapezoid whose cross-section is close to a rectangle.

10. The rotating member according to claim 1, wherein the shaft member is a crankshaft of an internal combustion engine, and one end face of the rotating member is an end face located on the internal combustion engine side when the rotating member is attached to the shaft member.

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