Method for sorting metal foil for spring components, method for manufacturing metal foil for spring components, and device for measuring the thickness of metal foil for spring components.

Abstract

The present invention provides a method for sorting metal foil for spring members, a method for manufacturing metal foil for spring members, and a device for measuring the thickness of metal foil for spring members, all of which enable the suppression of variations in the width of spring members in the thickness direction. [Solution] The method for selecting metal foil 21 for spring members includes measuring the thickness of rolled material obtained by rolling a base material using a thickness measuring device, and selecting the rolled material according to the measured thickness. Measuring the thickness includes measuring the thickness using a thickness measuring device such that the standard deviation of the thickness of the rolled material is 0.5 μm or less over a length of 60 m or less. Selecting includes selecting rolled material as metal foil 21 for spring members if the second difference value obtained by subtracting the minimum value from the maximum value of the rolled material thickness is 2.5 μm or less.

Description

Technical Field

[0004] ,

[0001] The present disclosure relates to a method for selecting a metal foil for a spring member, a method for manufacturing a metal foil for a spring member, and a thickness measuring device for a metal foil for a spring member.

Background Art

[0002] A camera module included in an electronic device with a camera, such as a tablet terminal or a smartphone, includes a drive mechanism for enabling autofocus and zoom. As drive mechanisms, a lens drive method and a sensor drive method are known. The drive mechanism of the lens drive method includes a spring member that enables changing the position of a lens in the optical axis direction of the lens. In contrast, the drive mechanism of the sensor drive method includes a spring member that enables changing the position of an image sensor in the optical axis direction of the lens (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0005] A method for selecting metal foil for spring members to solve the above problem is a method for selecting metal foil for spring members to be applied to spring members in which the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less. A method for manufacturing metal foil for spring members includes measuring the thickness of a rolled material obtained by rolling a base material using a thickness measuring device, and selecting the rolled material according to the measured thickness. The thickness measuring device includes an input roller for transporting the rolled material into a measurement area along the transport direction, an output roller for transporting the rolled material out of the measurement area along the transport direction, a thickness measuring sensor, a pair of tension rollers that sandwich the thickness measuring sensor in the transport direction, and a vibration suppression roller that, in the transport direction, sandwiches the pair of tension rollers together with the input roller or the output roller, and suppresses vibration of the rolled material by applying a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material. Measuring the thickness includes measuring the thickness using the thickness measuring device such that the standard deviation of the thickness in the rolled material is 0.5 μm or less over a length of 60 m or less. Selecting includes selecting the rolled material for use as metal foil for spring members if the second difference value obtained by subtracting the minimum value from the maximum value of the thickness of the rolled material is 2.5 μm or less.

[0006] A method for manufacturing metal foil for spring members to solve the above problems is a method for manufacturing metal foil for spring members in which the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less. The manufacturing method includes rolling a base material to obtain a rolled material, measuring the thickness of the rolled material using a thickness measuring device, and sorting the rolled material according to the measured thickness. The thickness measuring device comprises an input roller for transporting the rolled material into a measurement area along the transport direction, an output roller for transporting the rolled material out of the measurement area along the transport direction, a thickness measuring sensor, a pair of tension rollers that sandwich the thickness measuring sensor in the transport direction, and a vibration suppression roller that, in the transport direction, sandwiches the pair of tension rollers together with the input roller or the output roller and suppresses vibration of the rolled material by applying a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material. Measuring the thickness includes measuring the thickness using the thickness measuring device such that the standard deviation of the thickness in the rolled material is 0.5 μm or less over a length of 60 m or less. Selecting includes selecting the rolled material for use as metal foil for spring members if the second difference value obtained by subtracting the minimum value from the maximum value of the thickness of the rolled material is 2.5 μm or less.

[0007] The device for measuring the thickness of metal foil for spring members to solve the above problems is a device for measuring the thickness of metal foil for spring members, which is a rolled material applied to a spring member, where the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less. The device for measuring the thickness of metal foil for spring members comprises: a loading roller for loading the rolled material into a measurement area along the transport direction; an unloading roller for unloading the rolled material from the measurement area along the transport direction; a thickness measuring sensor; a pair of tension rollers that sandwich the thickness measuring sensor in the transport direction; and a vibration suppression roller that, in the transport direction, sandwiches the pair of tension rollers together with the loading roller or the unloading roller, and suppresses vibration of the rolled material by applying a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material.

[0008] According to the above configuration, the standard deviation obtained by the thickness measuring device is 0.5 μm or less, and the second difference value is 2.5 μm or less. Therefore, it is possible to keep the first difference value in the width of the spring member formed using metal foil for spring members to 2.0 μm or less.

[0009] In the above method for sorting metal foil for spring members, the thickness of the metal foil for spring members may be 30 μm or more and 200 μm or less. In the above method for sorting metal foil for spring members, the width of the rolled material is 200 mm or more and 700 mm or less, the rollers that sandwich the pair of tension rollers together with the vibration suppression roller among the loading roller and the unloading roller are the target rollers, and the distance between the vibration suppression roller and the target roller in the transport direction may be 240 mm or more and 550 mm or less.

[0010] According to the above method for sorting metal foil for spring components, it is possible to more reliably obtain the effect of suppressing vibration in the metal foil by the vibration suppression roller, and thus it is possible to obtain metal foil with more reliably suppressed variations in thickness measurements.

[0011] In the above method for sorting metal foil for spring members, the thickness measuring sensor repeatedly measures the thickness of the metal foil for spring members, and the measured thickness of the metal foil for spring members may be a plurality of values ​​measured each time the rolled material is transported along the transport direction for a length of 20 cm to 50 cm.

[0012] According to the above method for selecting metal foil for spring components, the thickness of the metal foil is measured at a frequency that allows the thickness at each part in the longitudinal direction of the metal foil to be reflected in the average thickness. Therefore, it is possible to obtain metal foil with a reduced difference between the median and average thickness.

[0013] In the above-described method for sorting metal foil for spring members, the thickness measuring device may be configured such that the center of each tension roller can move within a range of ±10 mm in the direction of the self-weight of the rolled material relative to a predetermined reference plane.

[0014] In the above method for sorting metal foil for spring components, the diameter of each tension roller may be between 10 mm and 50 mm. In the above method for sorting metal foil for spring members, the diameter of the discharge roller is 120 mm or more and 180 mm or less, the diameter of the vibration suppression roller is 100 mm or more and 150 mm or less, and the diameter of the discharge roller may be larger than the diameter of the vibration suppression roller.

[0015] In the above method for sorting metal foil for spring members, the length of the metal foil for spring members may be 60m or more and 180m or less. In the above method for selecting metal foil for spring members, the metal foil for spring members may include any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper.

[0016] According to the above method for selecting metal foil for spring members, it is possible to obtain spring members with high hardness, thereby increasing the durability of the spring members. [Effects of the Invention]

[0017] According to the method for selecting a metal foil for a spring member, the method for manufacturing a metal foil for a spring member, and the thickness measuring device for a metal foil for a spring member of the present disclosure, in a spring member using a metal foil for a spring member, it is possible to suppress variations in width in the thickness direction.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a plan view showing an example of the structure of a spring member manufactured using a metal foil for a spring member. [Figure 2] FIG. 2 is a cross-sectional view showing the structure along line II-II shown in FIG. 1. [Figure 3] FIG. 3 is a perspective view showing the structure of a metal foil for a spring member. [Figure 4] FIG. 4 is a process diagram showing a step in the method for manufacturing a metal foil for a spring member. [Figure 5] FIG. 5 is a process diagram showing a step in the method for manufacturing a metal foil for a spring member. [Figure 6] FIG. 6 is a device configuration diagram showing the thickness measuring device for a metal foil for a spring member of the present disclosure. [Figure 7] FIG. 7 is a device configuration diagram showing an enlarged part of the thickness measuring device shown in FIG. 6. [Figure 8] FIG. 8 is a device configuration diagram showing a conventional thickness measuring device for a metal foil for a spring member. [Figure 9] FIG. 9 is a process diagram showing a step in the method for manufacturing a spring member. [Figure 10] FIG. 10 is a process diagram showing a step in the method for manufacturing a spring member. [Figure 11] FIG. 11 is a process diagram showing a step in the method for manufacturing a spring member. [Figure 12] FIG. 12 is a process diagram showing a step in the method for manufacturing a spring member. [Figure 13] FIG. 13 is a process diagram showing a step in the method for manufacturing a spring member. [Figure 14]Figure 14 is a table showing the measurement results for Test Examples 1-1 to 1-16. [Figure 15] Figure 15 is a bar graph showing the results of dividing the mean by the median for test examples 1-1 to 1-16. [Figure 16] Figure 16 is a graph showing the average values ​​for spring width for test examples 1-1 to 1-16. [Figure 17] Figure 17 is a table showing the first and second difference values ​​for test examples 2-1 to 2-33. [Figure 18] Figure 18 is a graph showing the relationship between the first difference value and the second difference value. [Modes for carrying out the invention]

[0019] Referring to Figures 1 to 18, an embodiment of a method for sorting metal foil for spring members, a method for manufacturing metal foil for spring members, and an embodiment of a device for measuring the thickness of metal foil for spring members will be described. [Spring component] Refer to Figures 1 and 2 to illustrate the spring member to which the metal foil for spring members is applied.

[0020] As shown in Figure 1, the spring member 10 for the camera module has a first surface 10S1 and a second surface 10S2 opposite to the first surface 10S1. The spring member 10 includes an outer frame portion 11, an inner frame portion 12, and a spring portion 13. The spring portion 13 is a leaf spring.

[0021] The spring section 13 comprises a plurality of springs 13A. Each spring 13A has a linear shape that extends along the plane on which the spring member 10 expands, when viewed from a viewpoint opposite to the plane on which the spring member 10 expands. Each spring 13A is part of the metal foil that forms the spring member 10, and adjacent springs 13A are connected to each other by a bend.

[0022] In the example shown in Figure 1, the outer frame portion 11 has an octagonal shape, and the inner frame portion 12 has a circular shape. The spring portion 13 has a folded line shape. The outer shapes of the outer frame portion 11 and the inner frame portion 12 may be changed according to the shapes of other components of the drive mechanism of the camera module on which the spring member 10 is mounted, i.e., components other than the spring member 10. The spring portion 13 may have a structure in which a single wire is bent to make it appear as if multiple springs are lined up, or it may have multiple springs and have a structure in which the springs appear to be lined up. The inner frame portion 12 is located within the region defined by the outer frame portion 11. The spring portion 13 connects the inner frame portion 12 to the outer frame portion 11.

[0023] In the lens-driven mechanism, the spring member 10 is positioned on one side of the lens or sandwiched between the lens in the optical axis direction. By changing the position of the inner frame portion 12 connected to each outer frame portion 11 in the optical axis direction, the position of the lens in the optical axis direction changes. This makes it possible to correct camera shake using the lens-driven mechanism.

[0024] In contrast, in the sensor-driven drive mechanism, the spring member 10 is positioned on one side of the image sensor, or sandwiching the image sensor, in the optical axis direction of the lens. By changing the position of the inner frame portion 12 connected to each outer frame portion 11 in the optical axis direction, the position of the image sensor in the optical axis direction of the lens changes. This makes it possible to correct camera shake using the sensor-driven drive mechanism.

[0025] The electronic device on which the camera module equipped with the spring member 10 is mounted may be, for example, a mobile phone terminal, a smartphone, a tablet terminal, or a notebook personal computer.

[0026] Figure 2 shows the cross-sectional structure of the spring portion 13 along the line II-II shown in Figure 1. That is, Figure 2 shows the cross-sectional structure of the spring member 10 along a plane perpendicular to the first surface 10S1 of the spring member 10, and perpendicular to the direction in which each spring 13A extends.

[0027] As shown in Figure 2, in a cross-section perpendicular to the first surface 10S1, the spring portion 13 includes three or more springs 13A. In this cross-section, of the springs 13A, the springs 13A located at both ends in the direction in which the springs 13A are aligned are the outer springs 13A1. The direction in which the springs 13A are aligned is the first direction D1. Of the multiple springs 13A, the spring 13A sandwiched between the outer springs 13A1 in the first direction D1 is the inner spring 13A2. That is, the spring portion 13 comprises multiple springs 13A aligned along the first direction D1 in a cross-section perpendicular to the first surface 10S1. The multiple springs 13A include a pair of outer springs 13A1 and inner springs 13A2 sandwiched between the outer springs 13A1 in the first direction D1.

[0028] In the example shown in Figure 2, the spring portion 13 contains six springs 13A in a cross-section perpendicular to the first surface 10S1. Therefore, in the first direction D1, four inner springs 13A2 are sandwiched between two outer springs 13A1. The multiple springs 13A are arranged at approximately equal intervals in the first direction D1.

[0029] Of each spring 13A, the width on the first surface 10S1 is the first width WS1. Of each spring 13A, the width on the second surface 10S2 is the second width WS2. The inner spring 13A2 has a width of 10 μm or more on the first surface 10S1 and the second surface 10S2. The first width WS1 of the inner spring 13A2 is 10 μm or more, and the second width WS2 is 10 μm or more.

[0030] The outer spring 13A1 has the same width as the inner spring 13A2 on the first surface 10S1 and the second surface 10S2. The outer spring 13A1 may have a wider width than the inner spring 13A2.

[0031] In the spring member 10, the first difference value obtained by subtracting the minimum value from the maximum value of the second width WS2 on the second surface 10S2 is 2.0 μm or less. The second surface 10S2 is an example of a surface. That is, in the spring member 10, the first difference value is 2.0 μm or less in both the outer spring 13A1 and the inner spring 13A2. In addition, in each spring 13A, the difference value obtained by subtracting the minimum value from the maximum value of the first width WS1 on the first surface 10S1 is also 2.0 μm or less. Therefore, the first difference value may be set in the first width WS1 of the spring 13A. That is, the first surface 10S1 may be an example of a surface.

[0032] The thickness of the spring member 10 may be between 30 μm and 200 μm. The thickness of the spring member 10 is the distance between the first surface 10S1 and the second surface 10S2. That is, the thickness of the outer spring 13A1 and the thickness of the inner spring 13A2 may be between 30 μm and 200 μm.

[0033] In the direction in which the springs 13A are aligned, the distance between the centers of the springs 13A is the pitch P of the springs 13A. The pitch P may be the distance between the centers of the springs 13A on the first surface 10S1, or the distance between the centers of the springs 13A on the second surface 10S2. In either case, the pitch P is an equivalent value. The pitch P may be, for example, between 40 μm and 300 μm.

[0034] The spring member 10 is formed from a metal having a hardness high enough to achieve the required spring load or deflection. The spring member 10 may be formed from, for example, a stainless steel alloy or a copper alloy. The stainless steel alloy may be, for example, a stainless steel alloy specified in JIS G 4313:2011 "Stainless steel strips for springs". The copper alloy may be, for example, a copper alloy specified in JIS H 3130:2018 "Sheets and strips of beryllium copper, titanium copper, phosphor bronze, nickel-tin copper and nickel silver for springs".

[0035] The spring member 10 may include any of the following selected materials: stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. It is preferable that the spring member 10 be formed from any of the above selected materials. Since the spring member 10 can have high hardness, it is possible to increase the durability of the spring member 10.

[0036] [Metal foil for spring components] The metal foil for the spring component will be explained with reference to Figure 3. The metal foil 21 for spring members shown in Figure 3 (hereinafter also referred to as metal foil 21) is a metal foil 21 that is applied to a spring member 10 in which the width of the spring 13A on the second surface 10S2, that is, the first difference value obtained by subtracting the minimum value from the maximum value of the second width WS2, is 2.0 μm or less. The metal foil 21 for spring members shown in Figure 3 is also a metal foil 21 that is applied to a spring member 10 in which the difference value obtained by subtracting the minimum value from the maximum value of the first width WS1 on the first surface 10S1 is 2.0 μm or less. Furthermore, if the metal foil 21 suppresses the variation of the second width WS2 on the second surface 10S2 within a predetermined range, the variation of the spring width at each position in the thickness direction of the spring 13A will similarly be suppressed within a predetermined range.

[0037] The metal foil 21 is a rolled material. The metal foil 21 satisfies the following conditions 1 and 2. (Condition 1) Of the thickness T of the metal foil 21 measured using the thickness measuring device 30 (see Figure 6), the standard deviation σ of the thickness T of the metal foil 21 is 0.5 μm or less for a length of 60 m or less.

[0038] (Condition 2) Of the thickness T of the metal foil 21 measured using the thickness measuring device 30 (see Figure 6), the second difference value obtained by subtracting the minimum value from the maximum value of the thickness T of the metal foil 21 is 2.5 μm or less for a length of 60 m or less.

[0039] The metal foil 21 satisfies conditions 1 and 2 described above at the same measurement point within the metal foil 21. Since the standard deviation σ obtained by the thickness measuring device 30 is 0.5 μm or less, and the second difference value is 2.5 μm or less, it is possible to keep the first difference value in the width of the spring member 10 formed using the metal foil 21 to 2.0 μm or less.

[0040] The metal foil 21 has a strip shape extending along the length direction DL. The length direction DL is also the rolling direction of the metal foil 21. The direction perpendicular to the length direction DL is the width direction DW. In the strip-shaped metal foil 21, the length along the length direction DL is significantly larger than the width along the width direction DW. The metal foil 21 comprises a first surface 21S1 and a second surface 21S2 opposite to the first surface 21S1. Each surface 21S1, 21S2 has a strip shape along a plane defined by the length direction DL and the width direction DW. The thickness T of the metal foil 21 is the distance between the first surface 21S1 and the second surface 21S2.

[0041] The length of the metal foil 21 may be, for example, 60m or more and 180m or less. That is, the metal foil 21 may have a length of, for example, 60m or more and 180m or less along the length direction DL. The metal foil 21 may have a width of, for example, 200mm or more and 700mm or less along the width direction DW.

[0042] As described above, the metal foil 21 may include any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper.

[0043] [Method for manufacturing metal foil for spring components] A method for manufacturing the metal foil 21 for spring members will be described with reference to Figures 4 to 8. The method for manufacturing the metal foil 21 for spring members includes a method for selecting the metal foil for spring members.

[0044] The method for manufacturing the metal foil 21 produces a metal foil for a spring member 10 having a first difference value of 2.0 μm or less. This manufacturing method includes obtaining a rolled material, measuring its thickness, and sorting it. Obtaining the rolled material involves rolling the base material. Measuring the thickness involves measuring the thickness of the rolled material using a thickness measuring device 30. Sorting involves sorting the rolled material according to the measured thickness. The method for manufacturing the metal foil 21 will be described in more detail below with reference to the drawings.

[0045] Figures 4 and 5 schematically show the process of rolling the base material to form the metal foil 21. As shown in Figure 4, in the rolling process, first, a base material BM1 having a strip shape extending along the rolling direction DR is prepared. Next, the base material BM1 is conveyed along the conveying direction toward a rolling mill RE equipped with a pair of rolling rollers RL1 and RL2, so that the rolling direction DR of the base material BM1 and the conveying direction of the base material BM1 are parallel.

[0046] When the base material BM1 reaches between the pair of rolling rollers RL1 and RL2, the base material BM1 is rolled by the pair of rolling rollers RL1 and RL2. This reduces the thickness of the base material BM1 and stretches it along the conveying direction, thereby obtaining the rolled material BM2. The thickness of the base material may be, for example, 2.0 mm. The rolled material BM2 is wound onto the core C. Alternatively, the rolled material BM2 may be handled in a strip-like state without being wound onto the core C. The thickness of the rolled material BM2 is, for example, 30 μm to 200 μm, preferably 100 μm to 180 μm. That is, the thickness of the metal foil 21 may be, for example, 30 μm to 200 μm.

[0047] The thickness of the metal foil mentioned above is the thickness of the metal foil 21 when used in the manufacture of a spring member 10 having a first size. The thickness of the metal foil 21 used in the manufacture of a spring member 10 having a second size smaller than the first size may be, for example, 30 μm or more and 80 μm or less.

[0048] As shown in Figure 5, in order to remove the residual stress accumulated inside the rolled material BM2 formed by rolling the base material BM1, the rolled material BM2 is annealed using an annealing apparatus AE. This yields the rolled material BM3 after annealing. Since the annealing of the rolled material BM2 is performed while pulling the rolled material BM2 along the conveying direction, a rolled material BM3 with reduced residual stress can be obtained compared to the rolled material BM2 before annealing.

[0049] Furthermore, the material forming the base material BM1 may include any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper, as described above. Since these metals have high hardness, in other words, they are less ductile than metals with lower hardness, i.e., softer metals, variations in the degree of rolling are likely to occur within the base material BM1. Also, variations in the degree of rolling are likely to occur between multiple base material BM1.

[0050] Figure 6 shows the thickness measuring device used to measure the thickness of the rolled material BM3. As shown in Figure 6, the measurement process involves measuring the thickness of the rolled material BM3 using a thickness measuring device 30. The measurement process includes measuring the thickness of the rolled material BM3 using the thickness measuring device 30 over a length of 60 m or less, such that the standard deviation σ of the thickness of the rolled material BM3 is 0.5 μm or less.

[0051] The thickness measuring device 30 comprises a loading roller 31, an unloading roller 32, a thickness measuring sensor 33, a pair of tension rollers 34A and 34B, and a vibration suppression roller 35. The loading roller 31 loads the rolled material BM3 into the measuring area MA along the transport direction DC. The unloading roller 32 unloads the rolled material BM3 from the measuring area MA along the transport direction DC. The measuring area MA is an area extending along the transport direction DC and includes the thickness measuring sensor 33. In addition to the thickness measuring sensor 33, the measuring area MA of this disclosure includes a pair of tension rollers 34A and 34B and a vibration suppression roller 35.

[0052] A pair of tension rollers 34A and 34B sandwich the thickness measuring sensor 33 in the transport direction DC. The pair of tension rollers 34A and 34B consists of a first tension roller 34A and a second tension roller 34B. The vibration suppression roller 35 sandwiches the pair of tension rollers 34A and 34B together with the input roller 31 or output roller 32 in the transport direction DC. Furthermore, the vibration suppression roller 35 suppresses vibration of the rolled material BM3 by applying a load to the rolled material BM3 in the opposite direction to the direction in which the pair of tension rollers 34A and 34B apply a load to the rolled material BM3.

[0053] At any two points A and B aligned in the transport direction DC, the distance between the input roller 31 and point A is smaller than the distance between the input roller 31 and point B. In other words, the distance between the output roller 32 and point B is smaller than the distance between the output roller 32 and point A. In this case, point A is located upstream US in the transport direction DC than point B, and point B is located downstream DS in the transport direction DC than point A.

[0054] In the example shown in Figure 6, the pair of tension rollers 34A and 34B are located downstream DS of the feed roller 31. The pair of tension rollers 34A and 34B apply a predetermined load to the rolled material BM3 in a direction opposite to the direction of the rolled material BM3's own weight. As a result, the pair of tension rollers 34A and 34B generate a predetermined tension in the portion of the rolled material BM3 that passes through the thickness measuring sensor 33. Therefore, deflection and waviness are suppressed in the portion of the rolled material BM3 that passes through the thickness measuring sensor 33. The diameter of each tension roller 34A and 34B is smaller than the diameter of the vibration suppression roller 35.

[0055] The thickness measuring device 30 is equipped with a mechanism that allows for the individual adjustment of the positions of each tension roller 34A and 34B in the direction of the rolled material BM3's own weight. By adjusting the positions of the tension rollers 34A and 34B in the direction of their own weight, the tension of the rolled material BM3 can be adjusted.

[0056] In the example shown in Figure 6, the vibration-suppressing roller 35 is located upstream US of the pair of tension rollers 34A and 34B. As a result, the vibration-suppressing roller 35, together with the discharge roller 32, sandwiches the pair of tension rollers 34A and 34B and the thickness measuring sensor 33 located between the tension rollers 34A and 34B in the transport direction DC. The discharge roller 32 is an example of a target roller. The vibration-suppressing roller 35 applies a load to the rolled material BM3 along the direction of its own weight. As a result, the vibration-suppressing roller 35 suppresses vibration in the portion of the rolled material BM3 that is sandwiched between the discharge roller 32 and the vibration-suppressing roller 35.

[0057] The thickness measuring device 30 is equipped with a mechanism that allows adjustment of the position of the vibration-suppressing roller 35 in the direction of the rolled material BM3's own weight. By adjusting the position of the vibration-suppressing roller 35 in the direction of its own weight, it is possible to adjust the tension of the rolled material BM3.

[0058] As described above, the thickness measuring device 30 is equipped with a pair of tension rollers 34A and 34B and a vibration suppression roller 35. This makes it possible to measure the thickness of the rolled material BM3 using the thickness measuring device 30 such that the standard deviation σ of the measured thickness is 0.5 μm or less.

[0059] The transport roller 36 is, for example, a roller that transports the rolled material BM3, which has been washed and dried, toward the measurement area MA. The loading roller 31 loads the rolled material BM3, which is being transported by the conveying roller 36, into the measurement area MA. The loading roller 31 may be a conveying roller configured to transport the rolled material BM3 at a predetermined tension, for example. The diameters of the conveying roller 36 and the loading roller 31 may be larger than the diameter of the vibration suppression roller 35.

[0060] The discharge roller 32 is a conveying roller configured to convey the rolled material BM3 with a predetermined tension. The diameter of the discharge roller 32 may be larger than the diameter of the vibration suppression roller 35. The discharge roller 32 may be a roller that conveys the rolled material BM3 toward an area located downstream DS of the measurement area MA, where photoresist is applied to the rolled material BM3. Alternatively, the discharge roller 32 may be a roller that conveys the rolled material BM3 toward a winding roller located downstream DS of the discharge roller 32.

[0061] The thickness measuring device 30 may be located upstream US of the region where the photoresist is applied to or laminated to the rolled material BM3 in the roll-to-roll machine used to manufacture the spring member 10. Alternatively, the thickness measuring device 30 may be a device that unwinds the rolled material BM3 that has been wound onto the roll, and then winds the rolled material BM3 again after the thickness measurement is complete. In this case, for example, the conveying roller 36 may be the unwinding roller, and the roller located downstream DS of the discharge roller 32 may be the winding roller.

[0062] The distance between the loading roller 31 and the unloading roller 32 is the first distance DR1. The first distance DR1 is also the distance of the measurement area MA along the transport direction DC. The first distance DR1 may be, for example, 1000 mm or more and 1500 mm or less.

[0063] The distance between the discharge roller 32 and the vibration suppression roller 35 in the conveying direction DC is the second distance DR2. The second distance DR2 may be, for example, 240 mm or more and 500 mm or less. In the direction perpendicular to the conveying direction DC, the width of the rolled material BM3 may be 200 mm or more and 700 mm or less.

[0064] This makes it possible to more reliably obtain the effect of suppressing vibrations in the metal foil 21 by the vibration-suppressing roller 35, and thus obtain a metal foil 21 in which the variation in the measured thickness T is more reliably suppressed. As a result, it is possible to more reliably suppress the variation in width in the thickness direction of the spring 13A.

[0065] The thickness measuring sensor 33 repeatedly measures the thickness of the rolled material BM3 each time the rolled material BM3 is transported along the transport direction DC. The thickness measurement frequency only needs to be once every predetermined distance.

[0066] The thickness measuring device 30 may include a control unit that receives the measurement value from the thickness measuring sensor 33. The control unit may repeatedly measure the thickness of the rolled material BM3 each time the rolled material BM3 is transported for a length of 20 cm to 50 cm, and process the thickness data measured by the thickness measuring sensor 33. In this case, the control unit may calculate the mean, median, standard deviation σ, maximum value, minimum value, and a second difference value obtained by subtracting the minimum value from the maximum value through data processing.

[0067] Since the thickness of the metal foil 21 is defined as a measured value at a frequency that allows the thickness T at each part along the length DL of the metal foil 21 to be reflected in the average value of the thickness T, it is possible to obtain a metal foil 21 in which the difference between the median and average values ​​of the thickness T is suppressed. The thickness measuring sensor 33 may, for example, measure the thickness at the center of the rolled material BM3 in the width direction of the rolled material BM3 which is perpendicular to the transport direction DC.

[0068] The thickness measuring sensor 33 may be, for example, a laser coaxial displacement meter. In this case, the thickness measuring sensor 33 is equipped with two laser coaxial displacement meters. The two laser coaxial displacement meters are positioned so as to sandwich the rolled material BM3 in the direction of its own weight. As a result, the first laser coaxial displacement meter faces the first surface of the rolled material BM3, and the second laser coaxial displacement meter faces the second surface of the rolled material BM3. The second surface is the surface opposite to the first surface.

[0069] The pair of tension rollers 34A and 34B may apply a load to the rolled material BM3 in the direction of its own weight. In this case, the vibration suppression roller 35 applies a load to the rolled material BM3 in the direction opposite to the direction of its own weight. In this case, the positions of the pair of tension rollers 34A and 34B and the vibration suppression roller 35 relative to the rolled material BM3 are reversed from the device configuration shown in Figure 6. That is, in the direction of the rolled material BM3's own weight, the pair of tension rollers 34A and 34B are located above the rolled material BM3, and the vibration suppression roller 35 is located below the rolled material BM3.

[0070] Furthermore, the vibration-suppressing roller 35 may sandwich a pair of tension rollers 34A and 34B in the transport direction DC together with the loading roller 31. In this case, the vibration-suppressing roller 35 is located downstream DS of the pair of tension rollers 34A and 34B. The loading roller 31 is an example of the target roller. Also, the distance between the vibration-suppressing roller 35 and the loading roller 31 in the transport direction DC may be a second distance DR2. As described above, the second distance DR2 may be, for example, 240 mm or more and 550 mm or less.

[0071] Figure 7 is an enlarged view of the portion of the thickness measuring device 30 that is sandwiched between the vibration suppression roller 35 and the discharge roller 32 in the transport direction DC. As shown in Figure 7, the second distance DR2 is the sum of the third distance DR3, the fourth distance DR4, the fifth distance DR5, and the sixth distance DR6. The third distance DR3 is the distance between the vibration suppression roller 35 and the first tension roller 34A. The fourth distance DR4 is the distance between the discharge roller 32 and the second tension roller 34B. The fifth distance DR5 is the distance between the thickness measuring sensor 33 and the first tension roller 34A. The sixth distance DR6 is the distance between the thickness measuring sensor 33 and the second tension roller 34B. The fifth distance DR5 is equal to the sixth distance DR6.

[0072] The third distance DR3 may be between 70mm and 130mm. The fourth distance DR4 may be between 200mm and 300mm. The fifth distance DR5 and the sixth distance DR6 may be between 30mm and 50mm.

[0073] The diameter of the discharge roller 32 may be between 120 mm and 180 mm. The diameter of the vibration-damping roller 35 may be between 100 mm and 150 mm. The diameter of the discharge roller 32 is greater than the diameter of the vibration-damping roller 35. The diameter of the first tension roller 34A and the diameter of the second tension roller 34B may be between 10 mm and 50 mm.

[0074] The thickness measuring device 30 has a predetermined reference surface RP where the centers of the first tension roller 34A and the second tension roller 34B are located. The centers of each tension roller 34A and 34B are the parts through which the central axes of each tension roller 34A and 34B pass. The reference surface RP is a horizontal plane. The reference surface RP is, for example, located below the discharge roller 32 and the vibration suppression roller 35, and is the surface in contact with the discharge roller 32 and the vibration suppression roller 35. Each tension roller 34A and 34B is configured to be able to move its center within a range of ±10 mm in the direction of its own weight relative to the reference surface RP. For example, the direction of movement upward from the reference surface RP is the + direction, and the direction of movement downward from the reference surface RP is the - direction.

[0075] In the example shown in Figure 7, it is preferable that the centers of the first tension roller 34A and the second tension roller 34B are located above the reference plane RP by a range of 1 mm to 5 mm.

[0076] Furthermore, as described above, when a pair of tension rollers 34A and 34B apply a load to the rolled material BM3 along the direction of the rolled material BM3's own weight, the positions of each tension roller 34A and 34B are preferably set as follows. That is, it is preferable that the centers of the first tension roller 34A and the second tension roller 34B are located below the reference plane RP by a range of 1 mm to 5 mm.

[0077] In the thickness measuring device 30, the longer the second distance DR2, the less the vibration caused by the rollers affects the measurement of the rolled material BM3. On the other hand, the longer the second distance DR2, the greater the load that the vibration-suppressing roller 35 applies to the rolled material BM3, otherwise the tension of the rolled material BM3 at the measurement position of the thickness measuring device 30 will be low. Also, the shorter the second distance DR2, the more the vibration caused by the rollers affects the measurement of the rolled material BM3. On the other hand, the shorter the second distance DR2, the smaller the load that the vibration-suppressing roller 35 applies to the rolled material BM3 can be.

[0078] The sorting of rolled material BM3 by thickness measurement involves selecting rolled material BM3 as metal foil 21 if the second difference value obtained by subtracting the minimum value from the maximum value in thickness of rolled material BM3 is 2.5 μm or less. In other words, the conditions for determining that rolled material BM3 is acceptable as metal foil 21 for spring member 10 include the above-mentioned condition 2.

[0079] Furthermore, the standard deviation σ and the second difference value can be changed by changing at least one of the following: the rotational speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2. In other words, only one of the following may be changed: the rotational speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2. Alternatively, any two or more of the following may be changed: the rotational speed of the rolling rollers RL1 and RL2, the pressing force between the rolling rollers RL1 and RL2, the temperature of the rolling rollers RL1 and RL2, and the quantity of the rolling rollers RL1 and RL2.

[0080] In other words, in the rolling process, the base material BM1 should be rolled under predetermined rolling conditions such that the measurement values ​​from the thickness measuring device 30 satisfy conditions 1 and 2. Figure 8 shows a conventional thickness measuring device.

[0081] As shown in Figure 8, the conventional thickness measuring device 100 is equipped with an input roller 31, an output roller 32, a thickness measuring sensor 33, a first tension roller 34A, and a transport roller 36, but does not have a second tension roller 34B or a vibration suppression roller 35. As a result, the rolled material BM3 being transported vibrates due to vibrations generated by the input roller 31, the first tension roller 34A, the output roller 32, and the transport roller 36. Furthermore, the rolled material BM3 passing through the thickness measuring sensor 33 exhibits deflection and waviness.

[0082] As a result, the measurements obtained only include measurement errors due to the deflection, waviness, and vibration of the rolled BM3 material, in addition to the thickness variations inherent in the rolled BM3 material itself. Therefore, the measurement values ​​exhibit variability to the extent that the difference between the median and mean values ​​obtained from the measurements exceeds 1 μm. Furthermore, the standard deviation obtained from the measurements exhibits variability to the extent that it exceeds 2 μm.

[0083] When manufacturing the spring member 10 by wet etching the rolled material BM3, the wet etching conditions are set based on the average value of the thickness of the rolled material BM3. As described above, when using a conventional thickness measuring device, there is a large variation in the measured thickness. As a result, the second difference value in the thickness of the metal foil 21 exceeds 2.5 μm, and the first difference value in the width of the spring 13A, which is the result of wet etching, exceeds 2.0 μm.

[0084] Since the spring member 10 is manufactured using a roll-to-roll method, wet etching of the rolled material BM3 is also performed on the rolled material BM3 as it is being transported in the transport direction. One roll of rolled material BM3 has a length of 60m or more, and normally etching conditions corresponding to the thickness are applied to one roll of rolled material BM3. Therefore, as described above, if there is a large variation in the measured thickness of the rolled material BM3, even if the average value is the same, the transport speed is reduced to prevent excessive etching in the thinner parts compared to when the variation in measured values ​​is smaller. As a result, the production efficiency of the spring member 10 decreases.

[0085] [Method for manufacturing spring components] The manufacturing method for the spring member 10 will be explained with reference to Figures 9 to 13. In the manufacturing method described below, the cross-sectional structure of the spring member 10 shown in Figure 13 corresponds to the cross-sectional structure along the line XIII-XIII shown in Figure 1. That is, the method for manufacturing the spring member 10 shown in Figure 1 will be described below as an example of a manufacturing method for the spring member 10.

[0086] As shown in Figure 9, when manufacturing the spring member 10, first a first resist layer PR1 is formed on the first surface 21S1 of the metal foil 21, and a second resist layer PR2 is formed on the second surface 21S2. In the example described using Figures 7 to 11, each resist layer PR1 and PR2 is formed from a positive-type photoresist, but each resist layer PR1 and PR2 may be formed from a negative-type photoresist.

[0087] Next, as shown in Figure 10, the first photomask PM1 is placed on the first resist layer PR1, and the second photomask PM2 is placed on the second resist layer PR2. Then, the first resist layer PR1 is exposed using the first photomask PM1, and the second resist layer PR2 is exposed using the second photomask PM2.

[0088] As shown in Figure 11, the exposed resist layers PR1 and PR2 are developed to form the first resist mask RM1 from the first resist layer PR1 and the second resist mask RM2 from the second resist layer PR2.

[0089] As shown in Figure 12, the metal foil 21 is wet-etched using resist masks RM1 and RM2. During this process, the metal foil 21 is etched from both the first surface 21S1 and the second surface 21S2. This forms through-holes in the metal foil 21 that penetrate along the thickness direction of the metal foil 21, resulting in the formation of an outer frame portion 11, an inner frame portion 12 separated from the outer frame portion 11, and a spring portion 13 connecting the inner frame portion 12 to the outer frame portion 11.

[0090] As shown in Figure 13, after removing the resist masks RM1 and RM2 from the etched metal foil 21, the spring member 10 can be obtained by cutting it out from the etched metal foil 21.

[0091] In this embodiment, since the metal foil 21 satisfies conditions 1 and 2, it is easy to obtain a spring member 10 having the desired shape in the thickness direction of the metal foil 21. Furthermore, since the metal foil 21 satisfies conditions 1 and 2, it is possible to obtain a spring member 10 in which the variation in width in the thickness direction of the spring member 10 is kept within the range described above, without changing the wet etching conditions according to the variation in the thickness of the metal foil 21. Therefore, even if it is necessary to change the wet etching conditions according to the average thickness in the manufacturing of the spring member 10, it is not necessary to change the wet etching conditions according to the variation in thickness. This also makes it possible to eliminate errors in the combination of thickness variation and wet etching conditions.

[0092] [Example Test] Refer to Figures 14 to 18 to explain the test examples. [Test Examples 1-1 to 1-16] First, a base material BM1 made of titanium copper and having a thickness of 2.0 mm was subjected to a rolling process to form rolled material BM2. Next, rolled material BM2 was subjected to an annealing process. This resulted in rolled material BM3 for Test Examples 1-1 to 1-16, which had a length of 60 m, a width of 450 mm, and a design thickness of 150 μm. In Test Examples 1-1 to 1-16, the base material BM1 was rolled under rolling conditions such that rolled material BM3 satisfied conditions 1 and 2 described above.

[0093] [Exam Examples 2-1 to 2-33] First, a base material BM1 made of titanium copper with a thickness of 2.0 mm was subjected to a rolling process to form a rolled material. Next, the rolled material BM2 was subjected to an annealing process. This resulted in the rolled material BM3 of Test Examples 2-1 to 2-33, which had a width of 450 mm and a design thickness of 150 μm. In Test Examples 2-1 to 2-33, the base material BM1 was rolled under rolling conditions such that the rolled material BM3 satisfied conditions 1 and 2 described above.

[0094] [Method for measuring thickness] The thickness of the rolled material BM3 was measured using the thickness measuring device 30 described below. ·1st distance DR1: 1300mm • Second distance DR2: 450mm • Conveyor tension: 100N • Conveying speed: 1.5 m / min • Measurement frequency: 2 milliseconds / time • Measurement frequency: every 35cm • Measurement position: Center of the rolled material in the width direction • Laser coaxial displacement meter: CL-S015, manufactured by Keyence Corporation In the following, the rolled material BM3 obtained in each test example will be referred to as metal foil 21. For the metal foil 21 in each test example, the mean, median, standard deviation σ, maximum value, minimum value, and second difference value (maximum minus minimum value) were calculated from the thickness measurements taken every 35 cm.

[0095] [Wet etching] In each test example, a resist mask RM1, RM2 having multiple openings corresponding to the shape of the spring member 10 was formed on the first surface 21S1 and the second surface 21S2 of the metal foil 21 roll. Then, the metal foil 21 was wet-etched from both the first surface 21S1 and the second surface 21S2 using the two resist masks RM1, RM2. At this time, the wet etching conditions were set based on the average value of the thickness of the metal foil 21.

[0096] Furthermore, each roll was provided with a grid-like arrangement of unit regions, each corresponding to one spring member 10 and having a 20 mm square shape, so that they could be tiled in both the rolling direction DR and the width direction DW. Accordingly, each resist mask RM1 and RM2 also had a grid-like arrangement of unit patterns corresponding to the shape of one spring member 10, so that they could be tiled in both the rolling direction DR and the width direction DW.

[0097] In the unit pattern, in the portion of the spring member 10 that forms the folded spring portion 13, the opening width of the resist masks RM1 and RM2 corresponding to the gap between adjacent springs 13A that are parallel to each other in the spring portion 13 is set to 50 μm, and the pitch of adjacent springs 13A is set to 200 μm. Here, the pitch of adjacent springs 13A refers to the distance between the center lines set for each spring 13A in the etching pattern design, where adjacent springs 13A are parallel to each other. In addition, the design value of the width of the spring portion 13 in plan view in the etching pattern is set to 30 μm.

[0098] Furthermore, multiple unit patterns were formed on each resist mask RM1 and RM2 such that, in a plan view facing the first surface 21S1, the entirety of one unit pattern located on the first surface 21S1 overlaps the entirety of one unit pattern located on the second surface 21S2. Using these resist masks RM1 and RM2, multiple etching patterns corresponding to the shape of the spring member 10 were formed on each roll.

[0099] [How to measure width] A CNC image measurement system (NEXIV VMZ-R6555, manufactured by Nikon Solutions Corporation) was used to measure the width of spring 13A.

[0100] For each etching pattern manufactured using metal foil 21, the first width WS1 on the first surface 21S1 and the second width WS2 on the second surface 21S2 were measured for one spring 13A included in one spring portion 13. In each etching pattern, the spring 13A that is in the same position within the etching pattern was set as the measurement target for each etching pattern. In this test example, as an example, in each etching pattern, the spring 13A that is the third from the left in the left-right direction of the paper in the cross-sectional structure shown in Figure 2, which is in the cross-sectional structure along the line II-II shown in Figure 1, was set as the measurement target.

[0101] Then, the metal foil 21 was cut at a pitch of 35 cm along its length DL. This resulted in obtaining 171 sheets from the first 60 m of the metal foil 21 along its length DL. For each sheet, the average, maximum, and minimum values ​​of the width of the spring 13A, as well as the first difference value obtained by subtracting the minimum value from the maximum value, were calculated using the aforementioned measurements at the spring 13A located at the same coordinates within the sheet.

[0102] [Measurement results] The measurement results will be explained with reference to Figures 14 to 18. Note that in Test Example 1-16, the thickness of the metal foil was measured using a conventional thickness measuring device 100. As mentioned above, the conventional thickness measuring device 100 does not have a second tension roller 34B and a vibration suppression roller 35.

[0103] For the metal foil 21 in Test Examples 1-1 to 1-16, the measurement results for thickness and the average values ​​in width of spring 13A are as shown in Figure 14. As shown in Figure 14, the average thickness of the metal foil 21 was found to fall within the range of 149.1 μm to 151.4 μm. The median thickness of the metal foil 21 was also found to fall within the range of 149.2 μm to 151.4 μm. Furthermore, the standard deviation σ of the metal foil 21 thickness was between 0.2 and 0.5 in Test Examples 1-1 to 1-15, while it was 2.5 in Test Example 1-16. Additionally, the second difference value of the metal foil 21 was between 1.3 μm and 1.6 μm in Test Examples 1-1 to 1-15, while it was 14.3 μm in Test Example 1-16.

[0104] Furthermore, as shown in Figures 14 and 15, the value obtained by dividing the mean (A) by the median (B) (A / B) fell within the range of 1.000 to 1.001 in Test Examples 1-1 to 1-15, while it was found to be 0.989 in Test Example 1-16.

[0105] Thus, when the thickness of the metal foil 21 was measured using the thickness measuring device 30, it was found that the standard deviation σ was 0.5 or less, and the mean and median were approximately the same value. In contrast, when the thickness T of the metal foil 21 was measured using the conventional thickness measuring device 100, it was found that the deviation of the median from the mean was large.

[0106] Furthermore, as shown in Figures 14 and 16, the average width of spring 13A was found to be within the range of 29.2 μm to 30.9 μm in Test Examples 1-1 to 1-15. In other words, in Test Examples 1-1 to 1-15, the average width of spring 13A was found to be within ±1 μm of the design value of 30 μm. In contrast, in Test Example 1-16, the average width of spring 13A was found to be 33.1 μm.

[0107] Thus, it was found that the accuracy of the measurement of the thickness T of the metal foil 21, as measured using the thickness measuring device 30, was improved to the extent that the average value and the median value were almost identical. In contrast, it was found that the variation in the thickness T of the metal foil 21, as measured using the conventional thickness measuring device 100, was large.

[0108] In Test Examples 1-1 to 1-15, the variation in the width of the spring 13A in the thickness direction was suppressed, while in Test Example 1-16, a large variation in the width of the spring 13A in the thickness direction was observed. From these results, it can be said that with conventional thickness measuring devices, the variation in the measured thickness T is large, and therefore the variation in the width of the spring 13A obtained by wet etching is also increased.

[0109] As shown in Figure 17, in Test Examples 2-1 to 2-7, the second difference value of the thickness T measured over the first 60m was found to be between 1.1 μm and 1.6 μm. In Test Examples 2-8 to 2-12, the second difference value of the thickness T measured over the first 80m was found to be between 1.3 μm and 1.7 μm. In Test Examples 2-13 to 2-19, the second difference value of the thickness T measured over the first 100m was found to be between 1.6 μm and 1.9 μm. In Test Examples 2-20 to 2-26, the second difference value of the thickness T measured over the first 150m was found to be between 1.9 μm and 2.4 μm. In Test Example 2-27, the second difference value of the thickness T measured over the first 180m was found to be 2.5 μm. In contrast, in Test Examples 2-28 and 2-29, the second difference value in the thickness T measurement results for the first 180m was found to be between 2.6μm and 2.7μm. In Test Examples 2-30 to 2-33, the second difference value in the thickness T measurement results for the first 200m was found to be between 2.6μm and 3.2μm.

[0110] Furthermore, in Test Examples 2-1 to 2-7, the first difference value of the thickness T measured over the first 60m was found to be between 0.8 μm and 1.7 μm. In Test Examples 2-8 to 2-12, the first difference value of the thickness T measured over the first 80m was found to be between 1.4 μm and 1.7 μm. In Test Examples 2-13 to 2-19, the first difference value of the thickness T measured over the first 100m was found to be between 1.4 μm and 1.8 μm. In Test Examples 2-20 to 2-26, the first difference value of the thickness T measured over the first 150m was found to be between 1.6 μm and 2.0 μm. In Test Example 2-27, the first difference value of the thickness T measured over the first 180m was found to be 2.0 μm. On the other hand, in Test Examples 2-28 to 2-29, the first difference value in the thickness T measurement results for the first 180m was found to be between 2.4μm and 2.5μm. In Test Examples 2-30 to 2-33, the first difference value in the thickness T measurement results for the first 200m was found to be between 2.5μm and 2.9μm.

[0111] As shown in Figure 18, it was observed that the first difference value was kept below 2.0 μm when the second difference value was 2.5 μm or less. Conversely, it was observed that the first difference value exceeded 2.0 μm when the second difference value exceeded 2.5 μm. Thus, it can be said that the first difference value is kept below 2.0 μm when the second difference value is 2.5 μm or less.

[0112] Even if the manufacturing conditions for the spring component metal foil 21 are determined, variations may occur. Therefore, if conditions 1 and 2 are met by measuring up to 60m, etching can be performed under the same conditions, taking into account the length of the etching line. Depending on the metal foil, etching can be performed under the same conditions up to 180m, but it is practically difficult to meet conditions 1 and 2 for lengths beyond that. In that case, if conditions 1 and 2 are met again for the subsequent 60m, different etching conditions can be set and used.

[0113] As described above, according to one embodiment of the method for selecting metal foil for spring members, the method for manufacturing metal foil for spring members, and the thickness measuring device for metal foil for spring members, the following effects can be obtained.

[0114] (1) Since the standard deviation σ obtained by the thickness measuring device 30 is 0.5 μm or less, and the second difference value is 2.5 μm or less, it is possible to keep the first difference value in the width of the spring member 10 formed using the metal foil 21 to 2.0 μm or less.

[0115] (2) Since the vibration suppression effect of the vibration suppression roller 35 on the metal foil 21 can be obtained more reliably, it is possible to obtain a metal foil 21 in which the variation in the measured thickness T is more reliably suppressed. As a result, it is possible to more reliably suppress the variation in width in the thickness direction of the spring 13A.

[0116] (3) Since the thickness of the metal foil 21 is measured at a frequency that allows the thickness T at each part along the length DL of the metal foil 21 to be reflected in the average value of the thickness T, it is possible to obtain a metal foil 21 in which the difference between the median and average values ​​of the thickness T is suppressed.

[0117] (4) Since the spring member 10 can have high hardness, it is possible to increase the durability of the spring member 10. The above-described embodiment can be implemented with the following modifications.

[0118] [Spring section] As described above, the spring portion 13 may have a folded shape formed by bending a single plate at multiple bending points, or it may be composed of multiple plates that are independent of each other. When the spring member comprises multiple plates, each plate is connected to the inner frame portion and the outer frame portion. [Explanation of Symbols]

[0119] 10... Spring component 11…Outer frame 12...Inner frame section 13... Spring part 13A...spring 21... Metal foil for spring components 30…Thickness measuring device 31…Loading roller 32…Export Roller 33…Thickness measuring sensor 34A...First tension roller 34B...Second tension roller 35…Vibration-dampening roller

Claims

1. A method for selecting metal foil for spring members, applicable to spring members in which the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less, Measuring the thickness of the rolled material obtained by rolling the base material using a thickness measuring device, and, This includes sorting the rolled material according to the measured thickness, The thickness measuring device is, A transport roller that transports the rolled material into the measurement area along the transport direction, A discharge roller for discharging the rolled material from the measurement area along the aforementioned transport direction, Thickness measuring sensor, In the aforementioned transport direction, a pair of tension rollers sandwiching the thickness measuring sensor, In the aforementioned transport direction, the system includes vibration-suppressing rollers that, together with the loading roller or the unloading roller, sandwich the pair of tension rollers and apply a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material, thereby suppressing vibration of the rolled material. Measuring the aforementioned thickness includes measuring the thickness using the thickness measuring device such that the standard deviation of the thickness in the rolled material is 0.5 μm or less over a length of 60 m or less. The aforementioned sorting includes sorting the rolled material for use as metal foil for spring members, wherein the second difference value obtained by subtracting the minimum value from the maximum value in the thickness of the rolled material is 2.5 μm or less. A method for sorting metal foil for spring components.

2. The thickness of the metal foil for the spring member is 30 μm or more and 200 μm or less. A method for sorting metal foil for spring members according to claim 1.

3. The width of the rolled material is 200 mm or more and 700 mm or less. Of the aforementioned loading roller and the aforementioned unloading roller, the roller that sandwiches the pair of tension rollers together with the vibration suppression roller is the target roller. In the aforementioned conveying direction, the distance between the vibration-suppressing roller and the target roller is 240 mm or more and 550 mm or less. A method for sorting metal foil for spring members according to claim 1 or 2.

4. The thickness measuring sensor repeatedly measures the thickness of the metal foil for the spring member. The measured thickness of the metal foil for the spring member is determined by taking the measurement each time the rolled material is transported along the transport direction for a length of 20 cm to 50 cm. A method for sorting metal foil for spring members according to claim 1 or 2.

5. The thickness measuring device is configured such that the center of each tension roller can move within a range of ±10 mm relative to a predetermined reference plane in the direction of the rolled material's own weight. A method for sorting metal foil for spring members according to claim 1 or 2.

6. The diameter of each tension roller is between 10 mm and 50 mm. A method for sorting metal foil for spring members according to claim 1 or 2.

7. The diameter of the aforementioned discharge roller is 120 mm or more and 180 mm or less. The diameter of the vibration-suppressing roller is 100 mm or more and 150 mm or less. The diameter of the discharge roller is larger than the diameter of the vibration-suppressing roller. A method for sorting metal foil for spring members according to claim 1 or 2.

8. The length of the metal foil for the spring member is 60 m or more and 180 m or less. A method for sorting metal foil for spring members according to claim 1 or 2.

9. The metal foil for the spring member includes any of the following selected from the group consisting of stainless steel alloy, beryllium copper, nickel-tin copper, phosphor bronze, Corson alloy, and titanium copper. A method for sorting metal foil for spring members according to claim 1 or 2.

10. A method for manufacturing a metal foil for a spring member, wherein the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less, Rolling the base material to obtain rolled material, Measuring the thickness of the rolled material using a thickness measuring device, and This includes sorting the rolled material according to the measured thickness, The thickness measuring device is, A transport roller that transports the rolled material into the measurement area along the transport direction, A discharge roller for discharging the rolled material from the measurement area along the aforementioned transport direction, Thickness measuring sensor, In the aforementioned transport direction, a pair of tension rollers sandwiching the thickness measuring sensor, In the aforementioned transport direction, the system includes vibration-suppressing rollers that, together with the loading roller or the unloading roller, sandwich the pair of tension rollers and apply a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material, thereby suppressing vibration of the rolled material. Measuring the aforementioned thickness includes measuring the thickness using the thickness measuring device such that the standard deviation of the thickness in the rolled material is 0.5 μm or less over a length of 60 m or less. The aforementioned sorting includes sorting the rolled material for use as metal foil for spring members, wherein the second difference value obtained by subtracting the minimum value from the maximum value in the thickness of the rolled material is 2.5 μm or less. A method for manufacturing metal foil for spring components.

11. An apparatus for measuring the thickness of a rolled metal foil for a spring member, which is applied to a spring member where the first difference value obtained by subtracting the minimum value from the maximum value of the width on the surface of the spring is 2.0 μm or less, A transport roller that transports the rolled material into the measurement area along the transport direction, A discharge roller for discharging the rolled material from the measurement area along the aforementioned transport direction, Thickness measuring sensor, In the aforementioned transport direction, a pair of tension rollers sandwiching the thickness measuring sensor, The system includes, in the aforementioned transport direction, a vibration suppression roller that, together with the loading roller or the unloading roller, sandwiches the pair of tension rollers and applies a load to the rolled material in a direction opposite to the direction in which the pair of tension rollers apply a load to the rolled material, thereby suppressing vibration of the rolled material. A device for measuring the thickness of metal foil used in spring components.

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