WO2012032630A1 - 歯車 - Google Patents
歯車 Download PDFInfo
- Publication number
- WO2012032630A1 WO2012032630A1 PCT/JP2010/065482 JP2010065482W WO2012032630A1 WO 2012032630 A1 WO2012032630 A1 WO 2012032630A1 JP 2010065482 W JP2010065482 W JP 2010065482W WO 2012032630 A1 WO2012032630 A1 WO 2012032630A1
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- WIPO (PCT)
- Prior art keywords
- residual stress
- depth
- mpa
- less
- shot peening
- Prior art date
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/10—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for compacting surfaces, e.g. shot-peening
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P9/00—Treating or finishing surfaces mechanically, with or without calibrating, primarily to resist wear or impact, e.g. smoothing or roughening turbine blades or bearings; Features of such surfaces not otherwise provided for, their treatment being unspecified
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/17—Toothed wheels
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49462—Gear making
Definitions
- the present invention relates to a gear strengthened by applying residual stress to a gear whose surface is carburized.
- Patent Document 1 for the purpose of easily improving the fatigue strength of mechanical parts, a step of carburizing a gear, a step of nitriding, and a first shot peening that performs shot peening with a shot particle size of 0.8 mm A process and a second shot peening process in which shot peening is performed with a shot particle size of 0.1 mm are described.
- Patent Document 2 for the purpose of surface modification of alloy steel for machine structure, ultra-rapid and short-time heating and quenching treatment is performed after vacuum carburizing treatment, and shot peening is performed with a shot particle size of 0.6 mm. A first shot peening process and a second shot peening process for shot peening with a shot particle size of 0.08 mm are described.
- the root bending fatigue strength can be increased by setting the residual stress in the region having a depth of 20 ⁇ m or less from the surface to ⁇ 1400 MPa or less. That is, a stress (compressive stress) of ⁇ 1400 MPa or less is left in a region having a depth of 20 ⁇ m or less from the surface.
- a stress (compressive stress) of ⁇ 1400 MPa or less is left in a region having a depth of 20 ⁇ m or less from the surface.
- the conventional gear has the following problems.
- FIG. 8 shows the result of the CAE analysis of the gear when the conventional test (1) of shot peening treatment for increasing the root bending fatigue strength is performed.
- the analysis in FIG. 8 is a simulated analysis by carburizing the gear to HV750 and then hitting the shot grains having a particle size of 0.8 mm and a hardness of HV800 on the gear so that the shot marks overlap each other by three-quarters. I do.
- FIG. 12 is a distribution diagram of the residual stress of the gear in the shot peening test (1).
- the region P1 which is the region corresponding to the depth T of 100 ⁇ m from the surface P, has the maximum strain at S1.
- the strain is larger as it is closer to S1, and is smaller as it is closer to S6.
- the strain was S3 or more in the region P2 which is a region where the depth from the surface P is about 50 ⁇ m, and in the region P3 which is a region where the depth from the surface P (upward in the figure) is about 150 ⁇ m. .
- the residual stress in the regions E2 to E3 where the depth from the surface P is 50 ⁇ m or more and 150 ⁇ m or less is larger than other regions.
- the peak position E1 is also present in a region where the depth from the surface P is 50 ⁇ m or more and 150 ⁇ m or less.
- the region having a depth from the surface U corresponding to the region P where the strain was S1 was 100 ⁇ m. It was found that an internal crack Q occurred in Moreover, it turns out that the width
- the present inventor conducted a test of shot peening treatment for preventing internal cracks by reducing the residual stress as shown by the solid line D in FIG. I tried 2).
- the test is performed with shot grains having a particle diameter of 0.8 mm and a hardness of HV580.
- the residual stress in the regions D2 to D3 having a depth from the surface of 50 ⁇ m to 150 ⁇ m is compared with that in the shot peening test (1) shown in FIG. I was able to make it smaller. Further, the peak position D1 was also lower than E1.
- the residual stress in the region having a depth from the surface of 50 ⁇ m or more and 150 ⁇ m or less was reduced, but the depth from the surface requiring the tooth root bending strength was 20 ⁇ m or less.
- the residual stress becomes small and the strength becomes insufficient.
- the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gear having high tooth base bending strength and no chipping of a tooth tip.
- one aspect of the gear of the present invention has the following configuration.
- the residual stress in a region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1000 MPa or less; It is preferable that the residual stress in a region where the depth is 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more.
- the residual stress in the region where the depth from the surface is more than 150 ⁇ m and not more than 230 ⁇ m is preferably ⁇ 500 MPa or less.
- the residual stress in a region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1000 MPa or less;
- the residual stress in the region of 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more, so that the residual stress in the region of 5 ⁇ m or more and 20 ⁇ m or less of the depth from the surface against the fatigue fracture of the tooth root.
- the compressive stress is 1000 MPa or more
- the stress cancels the stress, and cracks do not occur on the surface of the tooth root. It can prevent fatigue fracture of the tooth root.
- the residual stress in the region where the depth from the surface is more than 150 ⁇ m and less than 230 ⁇ m is ⁇ 500 MPa or less, so that the Hertz stress generated by the contact between the tooth surfaces (the maximum value in the gear is the depth from the surface, Present in the vicinity of 200 ⁇ m), and the surface fatigue strength can be improved.
- the distribution map of the residual stress after performing a shot peening B process and a shot peening C process is represented.
- the distribution map of the residual stress of the gear in a shot peening B process is represented.
- the distribution map of the residual stress of the gear in shot peening C processing is represented.
- photographed the tooth tip cross section of the gear after performing the shot peening B process and the shot peening C process are represented.
- the figure equivalent to the micrograph shown in FIG. 4 is represented.
- or the shot peening C process is represented.
- the distribution map of the residual stress of the gear in a shot peening A process is represented.
- the distortion distribution figure by CAE analysis of the tooth tip cross section of the gear which performed the conventional shot peening is represented.
- photographed the tooth-tip cross section of the gearwheel of FIG. 8 are represented.
- the figure equivalent to the micrograph shown in FIG. 9 is represented.
- the distribution map of the residual stress of the gear in the test (1) of the shot peening treatment is shown.
- the distribution map of the residual stress of the gear in the test (2) of the shot peening treatment is shown.
- surface of the experimental result of a tooth missing is represented.
- a shot peening process is performed on the gear after the carburization process. Since the shot peening process is an essential part of the present invention, it will be described in detail.
- the shot peening treatment is widely used since a remarkable fatigue strength improvement effect has been confirmed.
- the compressive residual stress is applied by accelerating shots of shot grains using high-pressure air or a high-pressure water jet, jetting shot grains from a nozzle, and colliding with parts.
- the shot peening process is effective because the depth and peak value of residual stress can be controlled by the grain size and hardness of the shot grains, and the control range is very wide.
- the residual stress can be controlled from the outermost surface to 400 ⁇ m in depth, and the residual stress can be controlled from ⁇ 800 MPa to ⁇ 1600 MPa in peak value.
- the value of the residual stress generated can be increased by increasing the hardness of the shot particles. Further, by increasing the particle size of the shot particles, the peak position of the residual stress can be brought deeper from the surface of the member. On the other hand, by reducing the particle size of the shot particles, the peak position of the residual stress can be brought to a shallow position from the surface of the member.
- the shot peening process is performed in the order of the shot peening B processing process and the shot peening C processing process.
- the shot peening process is performed first in a deep range from the surface.
- Fig. 2 shows the distribution of residual stress in shot peening B treatment.
- the residual stress was measured with an X-ray stress measuring device (manufactured by Rigaku) (the same applies to the residual stress measurement in other distribution maps).
- the residual stress in the region corresponding to a depth from the surface of 50 ⁇ m to 150 ⁇ m is set to ⁇ 1000 MPa or more in order to prevent chipping. If the residual stress in the region where the depth from the surface is 50 ⁇ m or more and 150 ⁇ m or less can be ⁇ 1000 MPa or more, there will be no residual stress that causes ⁇ 1000 MPa or less causing internal cracks. Therefore, internal cracks do not occur and chipping of the tooth tip can be prevented.
- the grain size of shot grains is 1 mm. As shown in FIG. 2, by setting the grain size of the shot grains to 1 mm, the peak position of the residual stress can be set to a position of 50 ⁇ m or more and 150 ⁇ m or less.
- the hardness of the shot grains is HV450.
- the value of the residual stress can be set to ⁇ 1000 MPa or more.
- the solid line B is the position B1 which is the peak position with a residual stress of ⁇ 1000 MPa with a depth of 80 ⁇ m from the surface.
- the residual stress at position B2 where the depth from the surface is 50 ⁇ m is ⁇ 900 MPa
- the residual stress at position B3 where the depth from the surface is 150 ⁇ m is ⁇ 850 MPa. Therefore, in the region where the depth from the surface is 50 ⁇ m or more and 150 ⁇ m or less, the residual stress has a range of ⁇ 850 MPa to ⁇ 1000 MPa.
- the residual stress can be set to ⁇ 1000 MPa or more in a region where the depth from the surface is 50 ⁇ m to 150 ⁇ m.
- the shot particle size is 1 mm, but if the shot particle size is 0.8 mm or more and 1.2 mm or less by experiment, the hardness is set to HV450, and the depth from the surface is 50 ⁇ m or more. In the region corresponding to 150 ⁇ m or less, it was confirmed that the residual stress could be ⁇ 1000 MPa or more.
- FIG. 3 shows a distribution diagram of residual stress in the shot peening C process.
- the residual stress in the region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is set to ⁇ 1500 MPa or less in order to improve the strength of the portion to which the root bending fatigue stress is applied. If the residual stress in the region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less can be set to ⁇ 1500 MPa or less, the compressive stress cancels the stress when a repeated load (stress) is applied to the tooth, and the surface of the tooth root In this case, cracks do not occur and fatigue failure of the tooth root can be prevented. In the present embodiment, since it is ⁇ 1500 MPa or less, it naturally includes ⁇ 1000 MPa or less.
- the grain size of shot grains is 0.2 mm. As shown in FIG. 4, by setting the grain size of the shot grains to 0.2 mm, the peak position of the residual stress can be set to a position of 5 ⁇ m or more and 20 ⁇ m or less.
- the hardness of the shot grains is HV800.
- the value of the residual stress can be increased to ⁇ 1400 MPa or less.
- the solid line C is a position C1 which is a peak position with a residual stress of ⁇ 1600 MPa at a depth of 15 ⁇ m from the surface.
- the residual stress at the position C2 at a depth of 5 ⁇ m from the surface is ⁇ 1500 MPa
- the residual stress at the position C3 at a depth of 20 ⁇ m from the surface is ⁇ 1400 MPa. Therefore, the residual stress can be maintained as high as ⁇ 1400 MPa to ⁇ 1600 MPa in the region where the depth from the surface where the residual stress is required for preventing the root bending fatigue is 5 ⁇ m to 20 ⁇ m.
- the depth from the surface can be ⁇ 1400 MPa or less in the region corresponding to 5 ⁇ m or more and 20 ⁇ m or less.
- the shot particle size is 0.2 mm.
- the hardness is set to HV800, and the depth from the surface is reduced. It was confirmed that in the region corresponding to 5 ⁇ m or more and 20 ⁇ m or less, the pressure could be ⁇ 1400 MPa or less.
- FIG. 1 shows a distribution diagram of residual stress after performing shot peening B processing and shot peening C processing in the present embodiment.
- the residual stress of the gear in the present embodiment is indicated by a solid line A
- the resulting residual stress of the gear is shown as a broken line E.
- the solid line A appears as a line in which the respective distribution maps are gathered by performing the shot peening B process and the shot peening C process.
- the depth from the surface of the broken line E is ⁇ 650 MPa or more larger than the residual stress ⁇ 950 MPa of E1 corresponding to 5 ⁇ m or more and 20 ⁇ m or less.
- the residual stress in the region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1400 MPa or less (compressive stress is 1400 MPa or more) with respect to the fatigue stress at the tooth root.
- compressive stress cancels the stress, and internal cracks do not occur on the surface of the tooth root, and fatigue failure of the tooth root can be prevented.
- the residual stress in the regions A2 to A3 where the depth from the surface causing internal cracks is 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more. Therefore, since the residual stress is not large like the residual stress in the region where the depth from the surface of the broken line E is 50 ⁇ m or more and 150 ⁇ m or less, the strength is lower than that of the broken line E. However, although the residual stress is not large, it is necessary and sufficient if it is ⁇ 1000 MPa or more in order to maintain the strength of the gear. Therefore, the gear strength can be sufficiently maintained.
- FIG. 4 shows a micrograph and a scale obtained by photographing the tooth tip cross section of the gear 1 after performing the shot peening B process and the shot peening C process.
- FIG. 5 shows a view corresponding to the photomicrograph shown in FIG.
- an internal crack Q as shown in FIG. 10 occurs in R1, which is a region having a depth of 100 ⁇ m from the surface R of the gear 1 after the shot peening B treatment and the shot peening C treatment. Not done.
- the gear and gear manufacturing method according to the second embodiment adds shot peening A processing in addition to shot peening B processing and shot peening C processing, as compared with the gear and gear manufacturing method according to the first embodiment. There is no difference except the point. Therefore, in 2nd Embodiment, other description is omitted by demonstrating the residual stress of the last gear at the time of performing a shot peening B process and a shot peening C process.
- the shot peening A process is performed before the shot peening B process and the shot peening B process. That is, in the second embodiment, the shot peening process is performed in the order of shot peening A processing, shot peening B processing, and shot peening C processing.
- the second embodiment has the same operations and effects as the first embodiment.
- FIG. 7 shows a distribution diagram of residual stress in the shot peening A process.
- the grain size of shot grains is 2 mm. As shown in FIG. 7, by setting the grain size of the shot grains to 2 mm, the peak position of the residual stress can be set to a position exceeding 160 ⁇ m and not more than 230 ⁇ m.
- the hardness of the shot grains is HV700.
- HV700 the hardness of the shot grains
- the depth from the surface can be set to ⁇ 1000 MPa or less in a region corresponding to more than 160 ⁇ m and 230 ⁇ m or less.
- the solid line F is a position F1 which is a peak position with a residual stress of ⁇ 1300 MPa when the depth from the surface exceeds 160 ⁇ m and is 230 ⁇ m or less.
- the residual stress at position F2 at a depth of 160 ⁇ m from the surface is ⁇ 1000 MPa
- the residual stress at position F3 at a depth of 230 ⁇ m from the surface is ⁇ 1050 MPa. Therefore, in the region where the depth from the surface where the residual stress is required for preventing the root bending fatigue is from 160 ⁇ m to 230 ⁇ m, the residual stress can be kept as high as ⁇ 1000 MPa to ⁇ 1300 MPa.
- the depth from the surface can be reduced to ⁇ 1200 MPa or less in a region corresponding to more than 160 ⁇ m and not more than 230 ⁇ m.
- the residual stress at the position where the depth from the surface is 150 ⁇ m is ⁇ 900 ⁇ m
- the residual stress at the position F3 where the depth from the surface is 230 ⁇ m is ⁇ 1050 MPa.
- the residual stress can be kept as high as ⁇ 900 MPa to ⁇ 1300 MPa.
- the region having a depth from the surface of 150 ⁇ m to 230 ⁇ m is set to ⁇ 900 MPa or less.
- the applicant of the present invention sets the region having a depth from the surface of 150 ⁇ m to 230 ⁇ m to ⁇ 500 MPa or less. It was confirmed by experiments that the surface fatigue strength can be sufficiently maintained.
- FIG. 6 is a distribution diagram of residual stresses of gears subjected to shot peening A processing to shot peening C processing.
- the residual stress of the gear in this embodiment is indicated by a solid line X
- the load stress against bending is indicated by a broken first broken line Y
- the load stress against surface pressure is indicated by a broken second broken line Z.
- the solid line X appears as a line in which the respective distribution maps are aggregated by performing the shot peening A process to the shot peening C process.
- the residual stress of the Y1 bending load stress with a depth from the surface of the first broken line Y of 5 ⁇ m to 20 ⁇ m is ⁇ 1000 MPa.
- the residual stress of X1 having a depth from the surface of the solid line X corresponding to Y2 of 5 ⁇ m to 20 ⁇ m is ⁇ 1500 MPa. Therefore, by performing the shot peening A treatment, the residual stress with a depth from the surface of the gear of 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 500 MPa greater than the load stress for bending.
- the residual stress in the region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1400 MPa or less (compressive stress is 1400 MPa or more) with respect to the fatigue fracture of the tooth root.
- compressive stress is 1400 MPa or more
- the residual stress of the bending stress of Y1 having a depth from the surface of 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1000 MPa or less, it is not smaller than the bending stress. Therefore, when a load (stress) is repeatedly applied to the teeth, the compressive stress cancels the stress, cracks do not occur on the surface of the teeth, and fatigue failure of the teeth can be prevented.
- the residual stress of the applied stress with respect to the maximum surface pressure of Z1 in the range where the depth from the surface of the second broken line Z exceeds 160 ⁇ m and is 230 ⁇ m or less is ⁇ 1000 MPa or less.
- the residual stress of X4 until the depth from the surface of the corresponding solid line X exceeds 160 ⁇ m and is 230 ⁇ m or less it is ⁇ 1000 MPa or less. Therefore, by performing the shot peening A process, the residual stress from the surface of the gear to the depth of 160 ⁇ m to 230 ⁇ m is not smaller than the load stress with respect to the surface pressure.
- the maximum value of the gear is a depth from the surface in the vicinity of 200 ⁇ m
- the surface pressure fatigue strength can be improved.
- the residual stress of the second broken line Z1 is ⁇ 1000 MPa, but the magnitude of the load stress with respect to the surface pressure varies depending on the size of the gear and the like. Therefore, as a result of experiments on gears of various sizes, the applicant of the present invention has a residual stress of a load stress with respect to a surface pressure of ⁇ 500 MPa or less when the depth from the surface is 150 ⁇ m to 230 ⁇ m. It was confirmed by experiments that surface fatigue strength can be maintained.
- the load stress of the bending stress of Y2 is ⁇ 600 MPa or less in the region where the depth from the surface of the first broken line Y is 50 ⁇ m or more.
- the load stress of the surface pressure of Z2 is ⁇ 200 MPa or less.
- the residual stress of X2 having a depth of 50 ⁇ m or more from the surface of the solid line X is ⁇ 1000 MPa or more.
- the load stress of bending of Y3 is ⁇ 450 MPa or more.
- the load stress of the surface pressure of Z3 is ⁇ 700 MPa or more.
- the residual stress of X3 having a depth of 50 ⁇ m or more from the surface of the solid line X is ⁇ 1000 MPa or more.
- the solid line X has a residual stress of ⁇ 1000 MPa or more. Therefore, the residual stress of the solid line X becomes larger than the bending load stress of the first broken line Y and the load stress of the surface pressure of the second broken line Z.
- the probability of occurrence of internal cracks is low, and further, generation of chipping of the tooth tip can be prevented.
- gear and the manufacturing method of the gear of the present invention are not limited to the above embodiment, and various applications are possible.
- this embodiment it is performed by shot peening, but other wet blasting, ultrasonic shots, and strong processing can also be used.
- Hertzian stress caused by contact between tooth surfaces because the residual stress in the region where the depth from the surface exceeds 150 ⁇ m and not more than 300 ⁇ m does not increase uniformly from the peak of the residual stress whose depth from the surface is 150 ⁇ m or less.
- the maximum value of the depth from the surface is in the vicinity of 200 ⁇ m), and the surface pressure fatigue strength can be improved.
- a shot peening C treatment step of performing shot peening with a shot particle size of 0.3 mm or less has a depth from the surface of 5 ⁇ m or more and 20 ⁇ m or less with respect to fatigue fracture of the tooth root. Since the residual stress at ⁇ 1000 MPa or less (compressive stress is 1000 MPa or more), when a load (stress) is repeatedly applied to the teeth, the compressive stress cancels the stress and cracks occur on the surface of the tooth root. It is possible to prevent fatigue destruction of the tooth root.
- a shot peening B treatment step in which shot peening is performed with a shot particle diameter of 0.8 mm or more and 1.2 mm or less in order that the residual stress in a region having a depth from the surface of 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more; And by performing the shot peening C treatment step after the shot peening B treatment step, the residual stress in the region where the depth from the surface is 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more. Therefore, the occurrence of chipping of the tooth tip can be prevented.
- the shot peening C treatment step after the peening A treatment step By performing the shot peening C treatment step after the peening A treatment step, the Hertz stress generated by the contact between the tooth surfaces (the maximum value of the gear from the surface is near the depth of 200 ⁇ m) can be offset. And the surface pressure fatigue strength can be improved.
- the residual stress in the region where the depth from the surface is 5 ⁇ m or more and 20 ⁇ m or less is ⁇ 1000 MPa or less (compressive stress) due to the fatigue fracture of the tooth root. Therefore, when a repeated load (stress) is applied to the teeth, the compressive stress cancels the stress and cracks do not occur on the surface of the teeth, preventing fatigue failure of the teeth. it can.
- the residual stress in the region where the depth from the surface is 50 ⁇ m or more and 150 ⁇ m or less is ⁇ 1000 MPa or more, internal cracks do not occur, and chipping of the tooth tip can be prevented.
- the Hertzian stress caused by contact between the tooth surfaces (the maximum value of the gear has a depth from the surface in the vicinity of 200 ⁇ m) can be offset, and the surface pressure fatigue strength can be improved.
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Abstract
Description
第1に、歯車の強度としては、歯元曲げ疲労強度の他に、接触面圧による歯面の疲労破壊が問題となるが、特許文献1、2においては、面圧疲労強度について、考慮されていないため問題となる。
第1実施形態に関わる歯車にショットピーニングを施す製造工程について説明する。
浸炭処理後の歯車に対して、ショットピーニング処理を行う。ショットピーニング処理について本発明の本質部分となるため、詳細に説明する。
ショットピーニングB処理において、表面からの深さが50μm以上150μm以下にあたる領域の残留応力を付与する。
ショットピーニングC処理において、表面からの深さが5μm以上20μm以下にあたる領域に残留応力を付与する。表面からの深さが5μm以上20μm以下にあたる領域は、歯元曲げ疲労が掛かるため強度向上が求められるためである。図3に、ショットピーニングC処理における残留応力の分布図を示す。
図1に、本実施形態における、ショットピーニングB処理及びショットピーニングC処理を行った後の残留応力の分布図を示す。図1のうち、本実施形態おける歯車の残留応力を実線の実線Aで示し、上記図12に示した従来における歯車の歯元曲げの疲労強度を増すためのショットピーニング処理の試験(1)を行った歯車の残留応力を破線Eとして示す。実線Aは、ショットピーニングB処理及びショットピーニングC処理を行うことにより、それぞれの分布図が集合した形の線として表れる。
第2実施形態に係る歯車、歯車の製造方法は、第1実施形態に係る歯車、歯車の製造方法と比較して、ショットピーニングB処理及びショットピーニングC処理に加えてショットピーニングA処理を追加する点以外異なるところがない。そのため、第2実施形態においては、ショットピーニングB処理及びショットピーニングC処理を行った場合の最終の歯車の残留応力について説明することにより、その他の説明を割愛する。ショットピーングA処理は、ショットピーニングB処理及びショットピーニングB処理の前に行う。すなわち、第2実施形態においては、ショットピーニングA処理、ショットピーニングB処理、ショットピーニングC処理の順番でショットピーニング工程を行う。
ショットピーニングA処理において、表面からの深さが160μm超え230μm以下にあたる領域の残留応力を付与する。表面からの深さが160μm超え230μm以下にあたる領域は、歯車動作時に面圧疲労が掛かるため強度向上が求められるためである。図7に、ショットピーニングA処理における残留応力の分布図を示す。
図6に、ショットピーニングA処理乃至ショットピーニングC処理を行った歯車の残留応力の分布図を示す。
Claims (2)
- 表面が浸炭された歯車に残留応力を付与することにより強化された歯車において、
表面からの深さが、5μm以上20μm以下の領域における残留応力が、-1000MPa以下であること、
表面からの深さが、50μm以上150μm以下の領域における残留応力が、-1000MPa以上であること、
を特徴とする歯車。 - 請求項1に記載する歯車において、
表面からの深さが150μm超え230μm以下の領域における残留応力が、-500MPa以下であること、
を特徴とする歯車。
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PCT/JP2010/065482 WO2012032630A1 (ja) | 2010-09-09 | 2010-09-09 | 歯車 |
JP2012532781A JP5569588B2 (ja) | 2010-09-09 | 2010-09-09 | 歯車 |
EP10856979.9A EP2618028B1 (en) | 2010-09-09 | 2010-09-09 | Gear |
US13/821,636 US20130160899A1 (en) | 2010-09-09 | 2010-09-09 | Gear |
CN201080069037.XA CN103097774B (zh) | 2010-09-09 | 2010-09-09 | 齿轮 |
US14/539,695 US9457451B2 (en) | 2010-09-09 | 2014-11-12 | Method of manufacturing a gear |
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PCT/JP2010/065482 WO2012032630A1 (ja) | 2010-09-09 | 2010-09-09 | 歯車 |
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US13/821,636 A-371-Of-International US20130160899A1 (en) | 2010-09-09 | 2010-09-09 | Gear |
US14/539,695 Continuation US9457451B2 (en) | 2010-09-09 | 2014-11-12 | Method of manufacturing a gear |
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WO2012032630A1 true WO2012032630A1 (ja) | 2012-03-15 |
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EP (1) | EP2618028B1 (ja) |
JP (1) | JP5569588B2 (ja) |
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JP6275821B2 (ja) * | 2014-03-11 | 2018-02-07 | 本田技研工業株式会社 | 鋼部品およびその製造方法 |
JP2017036772A (ja) * | 2015-08-07 | 2017-02-16 | 本田技研工業株式会社 | 無段変速機 |
JP6530873B1 (ja) * | 2019-02-01 | 2019-06-12 | 株式会社不二機販 | 波動歯車減速機用歯車の表面処理方法 |
JP2022133587A (ja) * | 2021-03-02 | 2022-09-14 | 新東工業株式会社 | ショットピーニング方法 |
US20240200159A1 (en) * | 2022-12-14 | 2024-06-20 | Guangxi University | Method for compound strengthening treatment of gear surface |
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- 2010-09-09 JP JP2012532781A patent/JP5569588B2/ja not_active Expired - Fee Related
- 2010-09-09 CN CN201080069037.XA patent/CN103097774B/zh not_active Expired - Fee Related
- 2010-09-09 WO PCT/JP2010/065482 patent/WO2012032630A1/ja active Application Filing
- 2010-09-09 US US13/821,636 patent/US20130160899A1/en not_active Abandoned
- 2010-09-09 EP EP10856979.9A patent/EP2618028B1/en not_active Not-in-force
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Also Published As
Publication number | Publication date |
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CN103097774B (zh) | 2015-11-25 |
JP5569588B2 (ja) | 2014-08-13 |
EP2618028A4 (en) | 2015-07-22 |
US20130160899A1 (en) | 2013-06-27 |
US20150068039A1 (en) | 2015-03-12 |
CN103097774A (zh) | 2013-05-08 |
EP2618028B1 (en) | 2017-02-22 |
EP2618028A1 (en) | 2013-07-24 |
US9457451B2 (en) | 2016-10-04 |
JPWO2012032630A1 (ja) | 2013-12-12 |
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