Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
• • 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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F1/00—Springs
  • F16F1/02—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
• • 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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F1/00—Springs
  • F16F1/02—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
  • F16F1/04—Wound springs
  • F16F1/06—Wound springs with turns lying in cylindrical surfaces
• • 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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F1/00—Springs
  • F16F1/02—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
  • F16F1/14—Torsion springs consisting of bars or tubes

Definitions

• This invention relates to a method for treating metal components that can improve their resistance to settling, a setting device for metal components, and the metal components.
• Setting is typically performed during the manufacturing process of spring components such as torsion bars, coil springs, and leaf springs.
• Spring components are an example of the metal components referred to in this invention.
• setting is important for improving the resistance of spring components to settling.
• Typical setting involves applying a load to the spring component that exceeds the operating stress, causing plastic strain in the spring component.
• Hot setting in which the spring component is heated to a warm temperature, is also known to enhance the effect of setting.
• Patent Documents 1 and 2 describe examples of hot setting.
• Patent Document 3 describes examples of a setting device and setting method.
• conventional hot setting the entire spring member is heated in a furnace, and then a predetermined load is applied to the spring member removed from the furnace and held for a certain period of time (e.g., 70 minutes). This generates compressive residual stress in the surface of the spring member.
• the object of the present invention is to provide a processing method that can impart compressive residual stress, which is effective in improving settling resistance, to deep positions within a metal component, a setting device for the metal component, and the metal component.
• a residual stress stable portion where the magnitude of the compressive residual stress remains almost constant, may be present at a position deeper than the first depth.
• the first depth may be a position where the compressive residual stress is zero.
• the metal member may be a torsion bar, a coil spring, or a leaf spring.
• FIG. 2 is a front view showing a spring member as an example of a metal member.
• FIG. 1 is a front view schematically showing a setting device according to a first embodiment.
• FIG. 2 is a cross-sectional view schematically showing a surface heating portion of the metal member shown in FIG. 1 .
• 1 is a diagram showing the relationship between the depth from the surface of a metal component that has been subjected to surface heating setting and the magnitude of residual stress.
• FIG. 1 is a diagram showing the relationship between the depth from the surface of a metal component subjected to conventional hot setting and the magnitude of residual stress.
• FIG. 10 is a cross-sectional view schematically showing another example of a surface heating portion of a metal member.
• FIG. 10 is a cross-sectional view schematically showing another example of a surface heating portion of a metal member.
• FIG. 10 is a cross-sectional view schematically showing yet another example of a surface heating portion of a metal member.
• FIG. 10 is a front view schematically showing a setting device according to a second embodiment. 9 is a diagram showing the relationship between the depth from the surface of a metal member set by the setting device shown in FIG. 8 and the magnitude of residual stress.
• FIG. 10 is a front view showing another example of the metal member.
• FIG. 10 is a front view schematically showing a setting device according to a third embodiment. 12 is a front view of the setting device shown in FIG. 11 in a state where the load applied to the metal member is removed.
• FIG. FIG. 10 is a front view schematically showing a setting device according to a fourth embodiment.
• Figure 1 shows a torsion bar-type spring member 1A as an example of a metal member.
• Spring member 1A is made of spring steel and has a rod-shaped bar body 10, a first gripping portion 12, and a second gripping portion 14.
• the first gripping portion 12 is formed at the first end 11 of the bar body 10.
• the second gripping portion 14 is formed at the second end 13 of the bar body 10.
• Figure 2 shows a schematic diagram of the setting device 20.
• the setting device 20 performs setting while the surface of the metal member is heated.
• An example of a metal member is a spring member 1A.
• the setting device 20 includes a torsion mechanism 21 and a laser irradiation device 30.
• the torsion mechanism 21 applies a torsional load to the spring member 1A.
• the laser irradiation device 30 irradiates the spring member 1A with laser light.
• the torsion mechanism 21 is an example of a load application mechanism for applying a torsional load to the spring member 1A.
• the laser irradiation device 30 is an example of a surface heating device for rapidly heating the surface of the spring member 1A.
• the torsion mechanism 21 has a base member 22, a first member 23, a second member 24, and a drive unit 25.
• the first member 23 holds the first gripping portion 12 of the spring member 1A.
• the second member 24 holds the second gripping portion 14 of the spring member 1A.
• the base member 22 is substantially rigid. The second member 24 can be rotated by the drive unit 25 in a direction that twists the spring member 1A.
• the laser irradiation unit 32 can move along the guide member 35 in the length direction of the spring member 1A (indicated by arrow Y1 in Figure 2). A torsional load is applied to the spring member 1A by the torsion mechanism 21. Laser light 36 emitted from the laser irradiation unit 32 is irradiated onto the spring member 1A to which the torsional load is applied. The laser light 36 is irradiated toward the surface of the spring member 1A. The laser irradiation unit 32 then moves in the length direction of the spring member 1A. Therefore, the laser light 36 is irradiated onto the surface of the spring member 1A while moving in the length direction of the spring member 1A. The moving speed of the laser light 36 is, for example, 10 mm/second.
• Laser irradiation device 30 irradiates the surface of spring member 1A with laser light 36.
• the surface portion By irradiating with laser light 36, a relatively shallow region from the surface of spring member 1A (referred to as the surface portion) is rapidly heated to a temperature in the range of 200°C to 400°C.
• the area schematically shown by hatching in Figure 2 is the heated surface portion (referred to as the surface heated portion 38).
• a torsional load (e.g., 1270 MPa) is applied to the spring member 1A by the torsion mechanism 21. With the torsional load applied, the laser beam 36 moves in the longitudinal direction of the spring member 1A. In this way, a surface heating portion 38 over a length L1 is formed on the surface of the spring member 1A.
• Figure 3 is a schematic cross-sectional view of a radial section of spring member 1A heated by laser irradiation device 30.
• Spring member 1A is an example of a metal member.
• the densely hatched areas are surface heating portions 38.
• surface heating portions 38 are formed in the range indicated by angle ⁇ 2 in the circumferential direction of spring member 1A.
• Figure 4 shows the relationship between the depth from the surface of a metal component that has undergone surface-heat setting according to this embodiment and the magnitude of residual stress.
• Line segment L1 in Figure 4 shows the relationship between the depth from the surface of a metal component that has undergone surface-heat setting and the magnitude of residual stress.
• a metal component that has undergone surface-heat setting has compressive residual stress from the surface to a first depth D1 or to a position beyond the first depth D1.
• An example of the first depth D1 is a depth from the surface that exceeds 0.5 mm.
• a compressive residual stress region S1 is generated from the surface of the metal component to a first depth D1 or beyond the first depth D1.
• the absolute value of the compressive residual stress in the compressive residual stress region S1 increases from the first depth D1 toward the surface of the metal component, and the absolute value of the compressive residual stress reaches a maximum value P1 almost at the surface. "Almost at the surface” refers to the position of the compressive residual stress region S1 closest to the surface.
• the compressive residual stress portion S1 shown in Figure 4 includes an internal residual stress portion A1 extending from a first depth D1 to a second depth D2, and a surface residual stress portion A2 extending from the second depth D2 to the surface.
• the second depth D2 is shallower than the first depth D1.
• the rate of increase in compressive residual stress in the surface residual stress portion A2 is greater than the rate of increase in compressive residual stress in the internal residual stress portion A1.
• a residual stress-stable portion A3 is formed, where the magnitude of the compressive residual stress remains almost unchanged.
• the residual stress-stable portion A3 is an area that is not affected by setting or shot peening.
• the first depth D1 is the position where the compressive residual stress becomes zero.
• the first depth D1 may be the boundary between the compressive residual stress portion S1 and the residual stress-stable portion A3.
• the depth to which the surface portion heated by irradiation with laser light is heated depends on various factors, such as the thermal conductivity of the metal member and the intensity of the thermal energy applied to the metal member.
• the depth to which the surface portion to be heated may be targeted, for example, near the first depth D1 from the surface, or near the second depth D2. It may also be some other depth.
• Line segment L2 in Figure 4 shows the relationship between the depth from the surface of a metal component that has undergone surface heating setting and then shot peening and the magnitude of residual stress.
• Shot peening is a process in which a large number of shots are fired at the surface of a metal component at high speed. Shot peening can create a peak portion P1 near the surface of the metal component, where compressive residual stress is at its maximum.
• Line segment L4 in Figure 5 shows the relationship between the depth from the surface and the magnitude of residual stress in a metal component that has been subjected to conventional hot setting and then shot peening.
• the metal component that has been subjected to hot setting and then shot peening has a peak P3 near the surface where the absolute value of compressive residual stress is greatest.
• the compressive residual stress approaches zero.
• the depth of compressive residual stress in the conventional shot peened material shown by line segment L4 is about half the depth of compressive residual stress in the shot peened material of this embodiment shown by line segment L2 in Figure 4.
• Figure 6 is a cross-sectional view showing a schematic representation of another example of the surface heating portion 38 of the spring member 1A.
• the first surface heating portion 38a and the second surface heating portion 38b are formed symmetrically to each other, within the ranges of ⁇ 3 and ⁇ 4, respectively.
• by forming surface heating portions at multiple locations around the circumference of the spring member 1A and maintaining a load applied for a predetermined period of time it is possible to generate more plastic strain in the surface portion of the spring member 1A than in the interior.
• the AC current application device 50 is an example of a surface heating device for rapidly heating the surface portion of the spring member 1A.
• the AC current application device 50 includes a first electrode 51, a second electrode 52, and a power supply unit 53.
• the first electrode 51 is connected to the first end 11 of the spring member 1A.
• the second electrode 52 is connected to the second end 13 of the spring member 1A.
• the power supply unit 53 includes an AC power supply 54 and a control unit 55.
• the AC power supply 54 applies an AC voltage between the first electrode 51 and the second electrode 52.
• the control unit 55 controls the AC voltage.
• the compressive residual stress portion S2 includes an internal residual stress portion B1 and a surface residual stress portion B2.
• the internal residual stress portion B1 extends from the first depth D3 to the second depth D4.
• the surface residual stress portion B2 extends from the second depth D4 to the surface.
• the second depth D4 is shallower than the first depth D3.
• the rate of increase in compressive residual stress from the second depth D4 to the surface is greater than the rate of increase in compressive residual stress from the first depth D3 to the second depth D4.
• a residual stress-stable portion B3, where the magnitude of the compressive residual stress remains almost constant, is formed at a position deeper than the first depth D3.
• the residual stress-stable portion B3 is a region that is not affected by setting or shot peening.
• the first depth D3 is the position where the compressive residual stress becomes zero.
• the first depth D3 may be the boundary between the compressive residual stress portion S2 and the residual stress-stable portion B3.
• FIG. 10 is a front view showing a coil spring-type spring member 1B as another example of a metal member.
• the spring member 1B has a wire 60 made of spring steel.
• the spring member 1B includes a first end 61 and a second end 62. In a free state where no compressive load is applied to the spring member 1B, the spring member 1B has a length H1. When a compressive load is applied to the spring member 1B, the length H1 decreases depending on the magnitude of the load.
• FIG. 11 is a schematic front view of a setting device 70 according to the third embodiment.
• This setting device 70 has a base member 71, a compression mechanism 72, and a laser irradiation device 30.
• the base member 71 supports the spring member 1B.
• the compression mechanism 72 applies a compression load to the spring member 1B.
• the laser irradiation device 30 irradiates the spring member 1B with laser light 36.
• the compression mechanism 72 includes a pressure member 73 and a drive unit 74 that drives the pressure member 73.
• the compression mechanism 72 is an example of a load application mechanism.
• the load application mechanism applies a compressive load to the spring member 1B.
• the laser irradiation device 30 has a common configuration with the laser irradiation device 30 (shown in Figure 2) described in the first embodiment, so common components to the first embodiment are designated by common reference numerals and will not be described again.
• Figure 12 is a front view showing the state after the compressive load applied to spring member 1B has been removed. After the compressive load has been removed, spring member 1B has a length of H3. Although length H3 after setting is smaller than length H1 before setting, compressive residual stress is imparted from the surface of spring member 1B to a deep position. This spring member 1B has excellent resistance to settling.
• FIG. 13 is a schematic front view of a setting device 80 according to a fourth embodiment.
• the setting device 80 includes a compression mechanism 72 and an AC current applying device 50.
• the compression mechanism 72 applies a compressive load to a spring member 1B, which is an example of a metal member.
• the AC current applying device 50 applies an AC voltage to the spring member 1B.
• the AC current applying device 50 has a common configuration with the AC current applying device 50 (shown in FIG. 8 ) described in the second embodiment, and therefore, common components to the second embodiment are designated by common reference numerals and will not be described again.
• the compression mechanism 72 has a common configuration with the compression mechanism 72 (shown in FIG. 11 ) described in the third embodiment, and therefore, common components to the third embodiment are designated by common reference numerals and will not be described again.
• 1A, 1B ...spring member
• 20 ...setting device, 21...torsion mechanism (load application mechanism), 30...laser irradiation device (surface heating device), 38, 38a, 38b...surface heating section, 40...setting device, 50...alternating current application device (surface heating device), 70...setting device, 72...compression mechanism (load application mechanism), 80...setting device.

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Citations (8)

• 2025
  • 2025-03-21 JP JP2026511165A patent/JPWO2025205451A1/ja active Pending
  • 2025-03-21 WO PCT/JP2025/011092 patent/WO2025205451A1/ja active Pending

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