Rolling bearing cage unit

Abstract

The present rolling bearing retainer unit includes: a rolling bearing including an outer ring, an inner ring disposed coaxially with the outer ring on an inner peripheral side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and having a prescribed rotational axis; a bearing retainer disposed in contact with an outer peripheral surface of the outer ring or an inner peripheral surface of the inner ring of the rolling bearing; and a strain gauge including a resistance element that detects a strain of the outer ring or the inner ring, the bearing retainer including a thick wall portion and a thin wall portion thinner than the thick wall portion, the strain gauge being disposed at the thin wall portion, a pre-load that becomes a prescribed contact angle being applied to the rolling bearing, and the thick wall portion being disposed in contact with at least a region from an intersection of a straight line showing the contact angle and an outer peripheral surface of the outer ring or an inner peripheral surface of the inner ring to a pre-load side end surface of an end surface of the outer ring or the inner ring closer to the intersection.

Description

Technical Field

[0001] This invention relates to rolling bearing cage units. Background Technology

[0002] It is known to have a rolling bearing having an outer ring having a track surface on its inner circumference, an inner ring having a track surface on its outer circumference, and rolling elements disposed between the track surfaces of the outer ring and the inner ring, as well as a strain gauge for detecting the strain of the outer ring or the inner ring. For example, a structure in which a double-cylinder bearing component is provided for the rolling bearing, and a strain gauge is disposed on the bearing component (for example, see Patent Document 1).

[0003] <Prior art documents>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Patent No. 3766864 Summary of the Invention

[0006] <Problem to be solved by this invention>

[0007] However, in the case of a rolling bearing cage unit where a bearing cage is provided for the rolling bearing and a strain gauge is configured in the bearing cage, it is sometimes difficult to ensure the rigidity of the shaft inserted into the rolling bearing cage unit, depending on the construction of the bearing cage portion where the strain gauge is configured.

[0008] The present invention is made in view of the above points, and its object is to provide a rolling bearing cage unit that can suppress the reduction of the rigidity of the shaft caused by the structure of the part where the strain gauge is arranged.

[0009] <Methods for solving problems>

[0010] This rolling bearing cage unit includes: a rolling bearing comprising an outer ring, an inner ring coaxially disposed on the inner circumferential side of the outer ring and the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and having a predetermined axis of rotation; a bearing cage disposed in contact with the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and a strain gauge comprising a resistive element for detecting the strain of the outer ring or the inner ring, the bearing cage comprising a thick-walled portion and a thin-walled portion having a thickness thinner than the thick-walled portion, the strain gauge being disposed in the thin-walled portion, and a preload of a predetermined contact angle being applied to the rolling bearing, the thick-walled portion being disposed in contact with at least a region from the intersection of a straight line representing the contact angle and the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring to a preload-side end face of the outer ring or the inner ring that is close to the intersection point.

[0011] <The Effects of the Invention>

[0012] According to the disclosed technology, it is possible to provide a rolling bearing cage unit that can suppress the reduction in the rigidity of the shaft caused by the structure of the part where the strain gauge is configured. Attached Figure Description

[0013] Figure 1 This is a perspective view illustrating the rolling bearing cage unit of the first embodiment.

[0014] Figure 2 This is a diagram illustrating the rolling bearing cage unit of the first embodiment.

[0015] Figure 3 This is a diagram illustrating the contact angle.

[0016] Figure 4 This diagram illustrates the configuration of the thick-walled portion of the bearing cage.

[0017] Figure 5 The figure shown is (Figure 1) illustrating the usage of the rolling bearing cage unit 1.

[0018] Figure 6 This is a diagram (Figure 2) illustrating the usage of the rolling bearing cage unit 1.

[0019] Figure 7 This is a diagram illustrating the measurement length of a strain gauge.

[0020] Figure 8 This is a top view illustrating the strain gauge of the first embodiment.

[0021] Figure 9 This is a cross-sectional view illustrating the strain gauge of the first embodiment.

[0022] Figure 10 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the first embodiment, Example 1.

[0023] Figure 11 This is a cross-sectional view of a rolling bearing cage unit, which is an example of a variation of the first embodiment, exemplified by Example 2.

[0024] Figure 12 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the first embodiment, Example 3.

[0025] Figure 13 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the first embodiment, Example 4.

[0026] Figure 14 This is a cross-sectional view illustrating a rolling bearing cage unit according to a second embodiment.

[0027] Figure 15 This is a cross-sectional view of a rolling bearing cage unit, illustrating a variation of the second embodiment, Example 1.

[0028] Figure 16 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the second embodiment, Example 2.

[0029] Figure 17 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the second embodiment, Example 3.

[0030] Figure 18 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by a variation of the second embodiment, Example 4.

[0031] Figure 19 This is a perspective view illustrating a rolling bearing cage unit according to a third embodiment.

[0032] Figure 20 This is a cross-sectional view (1) illustrating a rolling bearing cage unit according to a fourth embodiment.

[0033] Figure 21 This is a cross-sectional view (2) illustrating a rolling bearing cage unit according to an example of the fourth embodiment. Detailed Implementation

[0034] Hereinafter, the mode of carrying out the invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same components, and sometimes repeated descriptions are omitted.

[0035] <First Implementation Method>

[0036] Figure 1 This is a perspective view illustrating the rolling bearing cage unit of the first embodiment. Figure 2 This is a diagram illustrating, by way of example, the rolling bearing cage unit of the first embodiment. Figure 2 (a) is the front view. Figure 2 (b) is a sectional view. Figure 2 (c) is the rear view.

[0037] Reference Figure 1 as well as Figure 2 The rolling bearing cage unit 1 includes a rolling bearing 2, a bearing cage 60, and a strain gauge 100. The rolling bearing 2 includes an outer ring 10, an inner ring 20, multiple rolling elements 30, a cage 40, and seals 51 and 52. It should be noted that... Figure 2 (a) and Figure 2 In (c), the illustrations of seals 51 and 52 are omitted for convenience.

[0038] The outer ring 10 is a cylindrical structure with the rotation axis m as its central axis. The inner ring 20 is a cylindrical structure arranged coaxially with the outer ring 10 on its inner circumference. Multiple rolling elements 30 are spheres disposed within a track 50 formed between the outer ring 10 and the inner ring 20. A lubricant such as lubricating oil (not shown) is sealed within the track 50. Seals 51 and 52 protrude from the inner circumference of the outer ring 10 towards the inner ring 20, isolating the track 50 from the outside.

[0039] On the inner circumferential surface of the outer ring 10, a recess 11 with an arc-shaped cross-section is formed in the circumferential direction of the outer ring 10. Additionally, on the outer circumferential surface of the inner ring 20, a recess 21 with an arc-shaped cross-section is formed in the circumferential direction of the inner ring 20. Multiple rolling elements 30 are guided circumferentially by the recesses 11 and 21.

[0040] The retainer 40 holds a plurality of rolling elements 30 disposed within the track 50. Specifically, the retainer 40 is an annular body coaxial with the rotation axis m, having a recess 41 on one side in the direction of the rotation axis m for receiving the rolling elements 30, and the other side forming a circumferentially continuous back portion 42 of the annular body.

[0041] The bearing cage 60 is configured to contact the outer peripheral surface of the outer ring 10, pressing against the outer peripheral surface of the outer ring 10 throughout its entire circumference. Here, contact with the outer peripheral surface of the outer ring 10 means not only that the bearing cage 60 is directly contacted to the outer peripheral surface of the outer ring 10 without other components, but also that it is indirectly contacted through other components such as adhesives. The bearing cage 60 may be pressed into the outer ring 10, for example. Alternatively, the bearing cage 60 may be bonded to the outer ring 10. The bearing cage 60 may be formed of, for example, a metal such as brass, aluminum, or stainless steel, or resin.

[0042] The bearing cage 60 includes a cylindrical (hollow cylindrical) thick-walled portion 61 and a cylindrical thin-walled portion 62 with a radial thickness thinner than the thick-walled portion 61. The length of the bearing cage 60 along its rotation axis m is approximately equal to the length of the outer ring 10 and the inner ring 20 along their rotation axes m. The lengths of the thick-walled portion 61 and the thin-walled portion 62 along their respective rotation axes m are shorter than the lengths of the outer ring 10 and the inner ring 20 along their rotation axes m. The inner diameters of the thick-walled portion 61 and the thin-walled portion 62 are approximately equal to the outer diameter of the outer ring 10 and are adjacent along their rotation axis m. The thick-walled portion 61 and the thin-walled portion 62 may, for example, be integrally formed.

[0043] In this embodiment, the thicknesses of the thick-walled portion 61 and the thin-walled portion 62 are approximately constant. The thin-walled portion 62 is a strain transmission portion that transmits the strain generated in the outer ring 10 during the rotation of the rolling element 30 to the strain gauge 100. The strain gauge 100 is disposed on the thin-walled portion 62 via an adhesive layer.

[0044] The strain gauge 100 is a sensor that detects the strain of the outer ring 10 or the inner ring 20, and includes a resistive element 103 as a sensing part, wiring 104, and a terminal part 105. The strain gauge 100 detects the change in the resistance value of the resistive element 103 as a result of the strain of the outer ring 10 or the inner ring 20.

[0045] In the strain gauge 100, the resistive element 103 is arranged, for example, with its length direction (measuring length direction) circumferentially aligned with the outer ring 10. Since the outer ring 10 is more flexible in the circumferential direction than in the circumferential direction, a larger strain waveform can be obtained by aligning the length direction of the resistive element 103 circumferentially with the outer ring 10. By monitoring the output of the strain gauge 100 with the aid of an external device, the strain generated in the outer ring 10 can be monitored.

[0046] Figure 3 This diagram illustrates the contact angle and is a cross-sectional view through the rotation axis m and the center of the rolling element 30. (See diagram for example.) Figure 3 As shown, a preload of a predetermined contact angle θ1 is applied to the outer ring 10 and the inner ring 20. By applying an appropriate preload to the outer ring 10 and the inner ring 20, it is possible to improve the oscillation accuracy of the rotating shaft and reduce vibration / noise.

[0047] Here, the contact angle θ1 is the angle formed by the straight line A connecting the contact point of the outer ring 10 and the rolling element 30 and the contact point of the inner ring 20 and the rolling element 30 in the cross-section, and the straight line B extending radially. O It is the intersection of the extension of line A in the sectional view and the outer perimeter of outer ring 10. (D) O The self-intersection point C of the outer perimeter of outer ring 10 in cross-section. O To be the intersection point C O The region near the preloaded side end face of the outer ring 10. Region D O This is the region where the rolling element 30 experiences significant displacement during rotation. It should be noted that the extension of line A is sometimes referred to as the line representing the contact angle.

[0048] Figure 4 This diagram illustrates the configuration of the thick-walled portion of the bearing cage, and is related to... Figure 2 The sectional view corresponding to (b). For example... Figure 4 As shown, the thick-walled portion 61 of the bearing cage 60 is at least in region D of the outer peripheral surface of the outer ring 10. O The bearing is configured in a connected manner. Thus, the thick-walled portion 61 of the bearing cage 60 is positioned relative to the region D where the rolling elements 30 experience significant displacement during rotation. O The shaft is configured in a connected manner. As a result, the reduction in the rigidity of the shaft inserted into the rolling bearing cage unit 1, which is caused by the construction of the part where the strain gauge 100 is configured, can be suppressed, thereby ensuring the rigidity of the shaft.

[0049] On the other hand, the area D removed from the outer periphery of the outer ring 10 O In the region where the displacement of the rolling element 30 during rotation is small, the thin-walled portion 62 of the bearing cage 60 can be arranged in this region. Furthermore, since the thickness of the thin-walled portion 62 is relatively thin, the strain generated in the outer ring 10 during the rotation of the rolling element 30 can be well transmitted to the strain gauge 100.

[0050] From the viewpoint of strain transferability, for the thickness of the thin-walled portion 62, it is preferable to obtain an output voltage of the strain gauge 100 that is approximately 10 times the noise component contained in the output. In the case where the strain gauge 100 constitutes one of the resistors of a Wheatstone bridge, for example, if the thin-walled portion 62 is cylindrical, then the thickness of the thin-walled portion 62 needs to be set to a thickness that satisfies the following formula (1).

[0051] (Mathematical Formula 1)

[0052]

[0053] In equation (1), t is the thickness of the thin-walled portion 62, P is the load applied to the thin-walled portion 62, L is the inner diameter of the thin-walled portion 62, n is the rotational speed of the rolling bearing 2, W is the length of the rotation axis m of the thin-walled portion 62, K is the sensitivity, V is the bridge voltage, E is the Young's modulus of the thin-walled portion 62, and e is the output voltage e of the strain gauge 100. o The noise voltage is contained within the inner ring of the output. However, with the inner ring fixed, L is the outer diameter of the thin-walled portion.

[0054] Equation (1) can be derived as follows. That is, since the shape of the thin-walled portion 62 can be specified and the strain ε can be obtained by simulation based on the finite element method, etc., the output voltage e can be estimated by importing it together with the parameters of the strain gauge into the following equation. o With this output voltage e o The thickness t of the thin-walled portion 62 can be calculated by reversing the ratio of the noise output e to approximately 10 times the average value.

[0055] Specifically, the strain ε is expressed by equation (2) using the bending moment M and the section modulus Z. Furthermore, the bending moment M and the section modulus Z are expressed by equations (3) and (4), respectively. Additionally, if the output voltage e... o If the output voltage is set to 10 times the noise voltage e, then the output voltage e o The noise voltage e is expressed by equation (5). Substituting equations (2) to (4) into equation (5) yields equation (6). If we move t to the right side of equation (6) and rearrange it, we can obtain equation (1).

[0056] (Mathematical Formula 2)

[0057] The above calculation example is used when the thin-walled portion 62 is cylindrical. By appropriately modifying the above formula according to the shape of the thin-walled portion 62, the required thickness of the thin-walled portion 62 can also be calculated.

[0058]

[0059] (Mathematical Formula 3)

[0060]

[0061] (Mathematical Expression 4)

[0062]

[0063] (Mathematical Formula 5)

[0064]

[0065] (Mathematical Expression 6)

[0066]

[0067] For example, when the outer ring 10 has a small diameter (e.g., approximately 30 mm), from the viewpoint of ensuring the rigidity of the shaft of the inserted rolling bearing cage unit 1, the thickness of the thick-walled portion 61 is preferably more than 10 times the bending rigidity of the thin-walled portion 62. For example, when the thin-walled portion 62 is cylindrical, the thickness of the thick-walled portion 61 is preferably about 3 times that of the thin-walled portion 62, in which case it becomes about 10 times the bending rigidity of the thin-walled portion 62.

[0068] It should be noted that the strain gauge 100 is preferably positioned in the thin-walled section 62, closer to the thick-walled section 61. This is because it is located at the intersection point C of the preload. O The closer the strain gauge, the greater the deformation due to load transfer. This further ensures the thickness of the thin-walled portion 62. Moreover, by configuring the end of the strain gauge 100 on the thick-walled portion 61 side to abut against the end face of the thin-walled portion 62 side of the thick-walled portion 61, the strain gauge 100 can be easily positioned.

[0069] For example, there may be cases where the outer ring 10 has a small diameter (e.g., approximately 30 mm), making it difficult to place the strain gauge 100 on the outer ring 10. In such cases, a bearing cage 60 having a thick-walled portion 61 and a thin-walled portion 62 can be placed on the outer periphery of the outer ring 10 of the rolling bearing 2, and the strain gauge 100 can be placed on the thin-walled portion 62. This allows for easy placement of the strain gauge 100. The strain of the outer ring 10 is transmitted to the strain gauge 100 via the thin-walled portion 62, which serves as a strain transmission unit, and can be detected by the strain gauge 100. Furthermore, the thick-walled portion 61 of the bearing cage 60 extends at least to the outer periphery of the outer ring 10 in region D. OThe interconnected configuration ensures the rigidity of the shaft inserted into the rolling bearing cage unit 1. Furthermore, by configuring the bearing cage 60 on the outer circumference of the outer ring 10 of the rolling bearing 2, replacement of the rolling bearing 2 is easy even in the event of a failure, resulting in excellent maintainability.

[0070] Figure 5 This is a diagram (Figure 1) illustrating the usage of the rolling bearing cage unit 1. For example... Figure 5 As shown, the two rolling bearing cage units 1 can be configured such that their respective rotation axes m are aligned and spaced apart by a specified interval, with their preload side end faces facing each other, and a shaft 200 inserted. This is because, as the preload direction is the back assembly (DB), the intersection of line A and the rotation axis m faces outward, thus increasing rigidity.

[0071] Figure 6 This is a diagram (Figure 2) illustrating the usage of the rolling bearing cage unit 1. For example... Figure 6 As shown, the two rolling bearing cage units 1 can be configured such that their respective rotation axes m are aligned and spaced apart by a specified interval, with the preload side end faces facing outwards, and inserted into the shaft 200. This is because, as the preload direction is the front combination (DF), the intersection of the straight line A and the rotation axis m faces inwards, thus, although rigidity is disadvantageous, the allowable amount of installation error is increased. Figure 5 Usage and Figure 6 The method of use can be selected appropriately according to the intended purpose.

[0072] Figure 7 This is a diagram illustrating the measurement length of a strain gauge. In Figure 7 In this context, θ2 is the angle formed by the two straight lines connecting the rotation axis m and the center of the adjacent rolling element 30. R is the inner diameter of the thin-walled portion 62 of the bearing cage 60. Preferably, the measuring length L of the strain gauge is smaller than the distance between adjacent rolling elements 30 of the rolling bearing 2; that is, preferably θ2 / 360×2π×R>L. This allows for the detection of strain on the outer ring 10 of each individual rolling element 30.

[0073] (Strain gauge)

[0074] Figure 8 This is a top view illustrating the strain gauge of the first embodiment. Figure 9 This is a cross-sectional view illustrating the strain gauge of the first embodiment, showing the strain gauge along... Figure 8 The cross-section of line AA. (Refer to...) Figure 8 as well as Figure 9 The strain gauge 100 has a substrate 101, a functional layer 102, a resistive element 103, wiring 104, and a terminal portion 105. However, the functional layer 102 can be configured as needed.

[0075] It should be noted that, in this embodiment, for convenience, the side of the strain gauge 100 with the resistive element 103 of the substrate 101 is designated as the upper side or one side, and the side without the resistive element 103 is designated as the lower side or the other side. Furthermore, the surface of each part with the resistive element 103 is designated as one surface or upper surface, and the surface without the resistive element 103 is designated as the other surface or lower surface. However, the strain gauge 100 can be used in an inverted state or configured at any angle. Additionally, "top view" refers to viewing the object from the normal direction of the upper surface 101a of the substrate 101, and "top view shape" refers to the shape of the object viewed from the normal direction of the upper surface 101a of the substrate 101.

[0076] The substrate 101 is a component that serves as a base layer for forming the resistor 103, etc., and it is flexible. Although the thickness of the substrate 101 is not particularly limited and can be appropriately selected according to the purpose, it can be set to about 5 μm to 500 μm, for example. In particular, if the thickness of the substrate 101 is 5 μm to 200 μm, the strain transferability of the strain-transferring surface (e.g., the thin-walled portion of the bearing cage) bonded to the lower surface of the substrate 101 by the adhesive layer and the dimensional stability to the environment are preferred, and if it is 10 μm or more, the insulation is even more preferred.

[0077] The substrate 101 is formed of an insulating resin film, for example, from PI (polyimide) resin, epoxy resin, PEEK (polyether ether ketone) resin, PEN (polyethylene naphthalate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, or polyolefin resin. It should be noted that the film refers to a flexible component with a thickness of approximately 500 μm or less.

[0078] Here, "formed from an insulating resin film" means that the substrate 101 does not preclude the presence of fillers, impurities, etc., in the insulating resin film. For example, the substrate 101 can be formed from an insulating resin film containing fillers such as silicon dioxide and aluminum oxide.

[0079] Materials other than resin used as the substrate 101 can include, for example, crystalline materials such as SiO2, ZrO2 (including YSZ), Si, Si2N3, Al2O3 (including sapphire), ZnO, and perovskite ceramics (CaTiO3, BaTiO3), as well as amorphous glass. Furthermore, metals such as aluminum, aluminum alloys (duralumin), and titanium can be used as the material for the substrate 101. In this case, an insulating film, for example, is formed on the metal substrate 101.

[0080] The functional layer 102 is formed on the upper surface 101a of the substrate 101 as the lower layer of the resistor 103. That is, the top view shape of the functional layer 102 is similar to... Figure 8The top view of resistor 103 is roughly the same.

[0081] In this application, a functional layer refers to a layer that at least has the function of promoting the crystal growth of the resistive element 103, which is the upper layer. Preferably, the functional layer 102 further has the function of preventing the oxidation of the resistive element 103 caused by oxygen and moisture contained in the substrate 101, and improving the adhesion between the substrate 101 and the resistive element 103. The functional layer 102 may also have other functions.

[0082] Since the insulating resin film constituting the substrate 101 includes oxygen and moisture, especially when the resistor 103 includes Cr (chromium), the functional layer 102 effectively includes the function of preventing the oxidation of the resistor 103 because Cr forms a self-oxidizing film.

[0083] The material of the functional layer 102 is not particularly limited as long as it has the function of promoting the crystal growth of the resistive body 103 in the upper layer. However, examples include one or more metals selected from the group consisting of Cr (chromium), Ti (titanium), V (vanadium), Nb (niobium), Ta (tantalum), Ni (nickel), Y (yttrium), Zr (zirconium), Hf (hafnium), Si (silicon), C (carbon), Zn (zinc), Cu (copper), Bi (bismuth), Fe (iron), Mo (molybdenum), W (tungsten), Ru (ruthenium), Rh (rhodium), Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Pd (palladium), Ag (silver), Au (gold), Co (cobalt), Mn (manganese), and Al (aluminum), alloys of any metal in the group, or compounds of any metal in the group.

[0084] Examples of the aforementioned alloys include FeCr, TiAl, FeNi, NiCr, and CrCu. Examples of the aforementioned compounds include TiN, TaN, Si3N4, TiO2, Ta2O5, and SiO2.

[0085] When the functional layer 102 is formed of a conductive material such as a metal or alloy, it is preferable that the film thickness of the functional layer 102 is less than 1 / 20 of the film thickness of the resistive element. If it is within such a range, it can promote the crystal growth of α-Cr, and a portion of the current flowing through the resistive element can flow through the functional layer 102, preventing a decrease in the detection sensitivity of strain.

[0086] When the functional layer 102 is formed of a conductive material such as a metal or alloy, it is more preferable that the film thickness of the functional layer 102 is less than 1 / 50 of the film thickness of the resistive element. If it is within such a range, it is possible to promote the crystal growth of α-Cr, and a portion of the current flowing through the resistive element flows through the functional layer 102, which can further prevent the reduction of strain detection sensitivity.

[0087] When the functional layer 102 is formed of a conductive material such as a metal or alloy, it is more preferable that the film thickness of the functional layer 102 is less than 1 / 100 of the film thickness of the resistive element. If it is in such a range, a portion of the current flowing through the resistive element flows through the functional layer 102, which can further prevent the reduction of strain detection sensitivity.

[0088] When the functional layer 102 is formed of an insulating material such as an oxide or nitride, the film thickness of the functional layer 102 is preferably set to 1 nm to 1 μm. If it is within this range, the crystal growth of α-Cr can be promoted, and the film can be easily formed without causing cracks in the functional layer 102.

[0089] When the functional layer 102 is formed of an insulating material such as an oxide or nitride, it is more preferable to set the film thickness of the functional layer 102 to 1 nm to 0.8 μm. If it is within such a range, the crystal growth of α-Cr can be promoted, and the film can be easily formed without causing cracks in the functional layer 102.

[0090] When the functional layer 102 is formed of an insulating material such as an oxide or nitride, it is even more preferable to set the film thickness of the functional layer 102 to 1 nm to 0.5 μm. If it is within this range, the crystal growth of α-Cr can be promoted, and the film can be easily formed without causing cracks in the functional layer 102.

[0091] It should be noted that the top view shape of functional layer 102 is, for example, similar to... Figure 8 The resistive element is patterned in a manner that is substantially the same as the top view shape of the resistive element. However, the top view shape of the functional layer 102 is not limited to being substantially the same as the top view shape of the resistive element. When the functional layer 102 is formed of an insulating material, it may not be patterned to be the same shape as the top view shape of the resistive element. In this case, the functional layer 102 is formed in a distributed manner at least in the region where the resistive element is formed. Alternatively, the functional layer 102 is formed in a distributed manner throughout the upper surface of the substrate 101.

[0092] Furthermore, when the functional layer 102 is formed of an insulating material, by making the thickness of the functional layer 102 relatively thick, ranging from 50 nm to 1 μm, and by forming it in a distributed manner, the increased thickness and surface area of ​​the functional layer 102 enable heat dissipation from the resistive element to the substrate 101 side. As a result, in the strain gauge 100, the reduction in measurement accuracy caused by the self-heating of the resistive element can be suppressed.

[0093] The resistive element 103 is a thin film formed in a prescribed pattern on the upper surface of the functional layer 102, and is a sensing part that generates resistance changes in response to strain.

[0094] The resistor 103 may be formed, for example, of a material including Cr (chromium), a material including Ni (nickel), or a material including both Cr and Ni. That is, the resistor 103 is formed of a material including at least one of Cr and Ni. As a material including Cr, for example, a Cr mixed-phase film can be cited. As a material including Ni, for example, Cu-Ni (copper-nickel) can be cited. As a material including both Cr and Ni, for example, Ni-Cr (nickel-chromium) can be cited.

[0095] Next, the case where the resistive element 103 is a Cr mixed-phase film will be explained as an example. Here, a Cr mixed-phase film refers to a film containing a mixture of Cr, CrN, Cr2N, etc. The Cr mixed-phase film may include unavoidable impurities such as chromium oxide. Furthermore, a portion of the material constituting the functional layer 102 may be diffused into the Cr mixed-phase film. In this case, sometimes the material constituting the functional layer 102 forms a compound with nitrogen. For example, when the functional layer 102 is formed of Ti, Ti and TiN (titanium nitride) may sometimes be included in the Cr mixed-phase film.

[0096] The thickness of the resistive element 103 is not particularly limited and can be appropriately selected according to the purpose, but it can be set to about 0.05 μm to 2 μm for example. In particular, it is preferable that if the thickness of the resistive element 103 is 0.1 μm or more, the crystallinity of the crystals constituting the resistive element 103 (e.g., the crystallinity of α-Cr) is improved, and it is more preferable that if it is 1 μm or less, the film cracks caused by the internal stress of the film constituting the resistive element 103 and the warping from the substrate 101 can be reduced.

[0097] By forming a resistive element 103 on the functional layer 102, a stable crystalline phase can be formed to improve the stability of instrument characteristics (sensitivity, temperature coefficient of sensitivity TCS, and temperature coefficient of resistance TCR).

[0098] For example, when the resistive element 103 is a Cr mixed-phase film, by providing the functional layer 102, a resistive element 103 with α-Cr (α-chromium) as the main component can be formed. Since α-Cr is a stable crystalline phase, the stability of the instrument characteristics can be improved.

[0099] Here, "principal component" refers to the object material comprising 50% or more by mass of all materials constituting the resistive element. When the resistive element 103 is a Cr mixed-phase film, from the viewpoint of improving instrument performance, it is preferable that the resistive element 103 includes 80% or more α-Cr, more preferably 90% or more by weight. It should be noted that α-Cr is Cr with a bcc structure (body-centered cubic lattice structure).

[0100] Furthermore, when the resistive element 103 is a Cr mixed-phase film, it is preferable that the CrN and Cr2N contained in the Cr mixed-phase film are 20% by weight or less. By containing CrN and Cr2N in the Cr mixed-phase film at 20% by weight or less, the decrease in sensitivity can be suppressed.

[0101] Furthermore, it is preferable that the proportion of Cr2N in CrN and Cr2N is 80% or more and less than 90% by weight, more preferably 90% or more and less than 95% by weight. By having the proportion of Cr2N in CrN and Cr2N be 90% or more and less than 95% by weight, the reduction in TCR (negative TCR) is further significantly achieved through the presence of Cr2N with semiconductor properties. Moreover, by reducing ceramization, a reduction in brittle fracture is achieved.

[0102] On the other hand, when trace amounts of N2 or atomic N are mixed into the membrane, they may detach from the membrane due to external environmental factors (such as high temperatures), resulting in changes in membrane stress. By generating chemically stable CrN, the aforementioned unstable N is not produced, thus enabling the acquisition of a stable strain gauge.

[0103] Furthermore, by diffusing the metal (e.g., Ti) constituting the functional layer 102 into the Cr mixed-phase film, the instrument characteristics can be improved. Specifically, the sensitivity of the strain gauge 100 can be 10 or higher, and the sensitivity temperature coefficient TCS and the resistance temperature coefficient TCR can be within the range of -1000ppm / ℃ to +1000ppm / ℃.

[0104] Terminal portion 105 extends from both ends of resistor 103 via wiring 104, and in plan view, it is wider than resistor 103 and wiring 104, forming a generally rectangular shape. Terminal portion 105 is a pair of electrodes used to output the change in resistance value of resistor 103 caused by strain to the outside. Resistor 103 extends in a zigzag manner from one of terminal portion 105 and wiring 104 and connects to the other wiring 104 and terminal portion 105. The upper surface of terminal portion 105 can be covered with a metal that has better solderability than terminal portion 105.

[0105] It should be noted that although the resistor 103, wiring 104 and terminal 105 are given different reference numerals for convenience, they can be integrally formed from the same material in the same process.

[0106] Alternatively, a cover layer 106 (insulating resin layer) can be provided on the upper surface 101a of the substrate 101, such that the terminal portion 105 is exposed while the resistor 103 and wiring 104 are covered. By providing the cover layer 106, mechanical damage to the resistor 103 and wiring 104 can be prevented. In addition, by providing the cover layer 106, the resistor 103 and wiring 104 can be protected from moisture. It should be noted that the cover layer 106 can be configured to cover the entire portion except for the terminal portion 105.

[0107] The capping layer 106 can be formed, for example, from an insulating resin such as PI resin, epoxy resin, PEEK resin, PEN resin, PET resin, PPS resin, or composite resin (e.g., silicone resin, polyolefin resin). The capping layer may contain fillers and pigments. The thickness of the capping layer is not particularly limited and can be appropriately selected according to the purpose, but for example, it can be set to approximately 2 μm to 30 μm.

[0108] To manufacture the strain gauge 100, firstly, a substrate 101 is prepared, and a functional layer 102 is formed on the upper surface 101a of the substrate 101. The materials and thicknesses of the substrate 101 and the functional layer 102 are as described above. However, the functional layer 102 can be configured as needed.

[0109] The functional layer 102 can be formed using materials capable of forming the functional layer 102, and vacuum film can be formed by introducing Ar gas into the chamber. By using the conventional sputtering method, since the functional layer 102 is formed while etching the upper surface 101a of the substrate 101 with Ar, the amount of film formed in the functional layer 102 can be minimized and the adhesion can be improved.

[0110] However, this is just one example of the film formation method for the functional layer 102, and other methods can also be used to form the functional layer 102. For example, the following method can be used: before forming the functional layer 102, the upper surface 101a of the substrate 101 is activated by plasma treatment such as Ar to obtain an improved adhesion effect, and then the functional layer 102 is formed by vacuum film formation by magnetron sputtering.

[0111] Next, after a metal layer is formed on the upper surface of the functional layer 102 to form the resistor 103, wiring 104, and terminal portion 105, the functional layer 102, resistor 103, wiring 104, and terminal portion 105 are patterned by photolithography. Figure 8The top view shown is illustrated. The materials and thicknesses of the resistor 103, wiring 104, and terminal portion 105 are as described above. The resistor 103, wiring 104, and terminal portion 105 are integrally formed from the same material. The resistor 103, wiring 104, and terminal portion 105 can be deposited, for example, by magnetron sputtering using raw materials capable of forming the resistor 103, wiring 104, and terminal portion 105. The resistor 103, wiring 104, and terminal portion 105 can be deposited using reactive sputtering, vapor deposition, arc ion plating, pulsed laser deposition, or other methods instead of magnetron sputtering.

[0112] The combination of materials for the functional layer 102 with those for the resistor 103, wiring 104, and terminal 105 is not particularly limited and can be appropriately selected according to the purpose. For example, Ti can be used to form a film for the functional layer 102, and Cr mixed phase film with α-Cr (α-chromium) as the main component can be formed for the resistor 103, wiring 104, and terminal 105.

[0113] In this case, for example, a raw material capable of forming a Cr miscible film can be used as the target material, and a film can be formed on the resistor 103, wiring 104, and terminal portion 105 by magnetron sputtering with Ar gas introduced into the chamber. Alternatively, pure Cr can be used as the target material, and an appropriate amount of nitrogen gas can be introduced into the chamber along with Ar gas, and a film can be formed on the resistor 103, wiring 104, and terminal portion 105 by reactive sputtering. In this case, by changing the amount of nitrogen introduced, the pressure (nitrogen partial pressure), and setting a heating process to adjust the heating temperature, the ratio of CrN and Cr2N contained in the Cr miscible film, as well as the ratio of Cr2N in CrN and Cr2N, can be adjusted.

[0114] In these methods, the growth surface of the Cr mixed-phase film is defined based on the functional layer 102 composed of Ti, enabling the formation of a Cr mixed-phase film with a stable crystalline structure, i.e., α-Cr as the main component. Furthermore, the instrument characteristics are improved by the diffusion of Ti constituting the functional layer 102 into the Cr mixed-phase film. For example, the sensitivity of the strain gauge 100 can be 10 or higher, and the sensitivity temperature coefficient (TCS) and resistance temperature coefficient (TCR) can be within the range of -1000 ppm / ℃ to +1000 ppm / ℃.

[0115] It should be noted that when the resistive element 103 is a Cr mixed-phase film, the functional layer 102 composed of Ti includes all of the following functions: promoting the crystal growth of the resistive element 103, preventing the oxidation of the resistive element 103 caused by oxygen and moisture contained in the substrate 101, and improving the adhesion between the substrate 101 and the resistive element 103. The same applies when Ta, Si, Al, or Fe are used instead of Ti as the functional layer 102.

[0116] Subsequently, as needed, the strain gauge 100 is completed by providing a cover layer 106 on the upper surface 101a of the substrate 101, which covers the resistive element 103 and the wiring 104, exposing the terminal portion 105. The cover layer 106 is manufactured, for example, by laminating a semi-cured thermosetting insulating resin film onto the upper surface 101a of the substrate 101 in such a way that it covers the resistive element 103 and the wiring 104, exposing the terminal portion 105, and then heating it to cure it. Alternatively, the cover layer 106 can be manufactured by coating a liquid or paste-like thermosetting insulating resin onto the upper surface 101a of the substrate 101 in such a way that it covers the resistive element 103 and the wiring 104, exposing the terminal portion 105, and then heating it to cure it.

[0117] Thus, by providing a functional layer 102 on the lower layer of the resistive element 103, the crystal growth of the resistive element 103 can be promoted, and a resistive element 103 composed of a stable crystalline phase can be manufactured. As a result, the stability of the instrument characteristics in the strain gauge 100 can be improved. In addition, by the diffusion of the material constituting the functional layer 102 into the resistive element 103, the instrument characteristics in the strain gauge 100 can be improved.

[0118] It should be noted that the strain gauge 100, which uses a Cr mixed-phase film as the resistive element 103, achieves high sensitivity (more than 500% higher than before) and miniaturization (less than 1 / 10 of the previous size). For example, the output of a conventional strain gauge is about 0.04 mV / 2V, while the strain gauge 100 can achieve an output of more than 0.3 mV / 2V. In addition, the size (measuring length × measuring width) of a conventional strain gauge is about 3 mm × 3 mm, while the size (measuring length × measuring width) of the strain gauge 100 can be miniaturized to about 0.3 mm × 0.3 mm.

[0119] Thus, the strain gauge 100, which uses a Cr mixed-phase film as the resistive element 103, is small and can be easily attached to the thin-walled portion 62 of the bearing cage 60. Therefore, it is particularly suitable for use in rolling bearing cage units for small rolling bearings 2 with a diameter (outer diameter of the outer ring 10) of 30 mm or less. In addition, the strain gauge 100, which uses a Cr mixed-phase film as the resistive element 103, has high sensitivity and can detect small displacements, thus enabling the detection of minute strains that were previously difficult to detect. In other words, by using a strain gauge 100, which uses a Cr mixed-phase film as the resistive element 103, a rolling bearing cage unit 1 with high-precision strain detection function can be realized.

[0120] <Modifications of the First Embodiment>

[0121] In a variation of the first embodiment, another example of a bearing cage mounted on the outer peripheral surface of the outer ring is shown. It should be noted that in this variation of the first embodiment, descriptions of components identical to those in the already described embodiments are sometimes omitted.

[0122] Figure 10 This is a cross-sectional view of a rolling bearing cage unit, illustrating a variation of the first embodiment 1, showing the relationship with... Figure 2 The section corresponding to (b). For example... Figure 10 As shown, the rolling bearing cage unit 1A differs from the rolling bearing cage unit 1 (refer to...) in that the bearing cage 60 is replaced by the bearing cage 60A. Figure 2 (etc.) are different.

[0123] The bearing cage 60A has a cylindrical large-diameter portion 61A and a cylindrical small-diameter portion 62A. The small-diameter portion 62A is integrally disposed on the outer periphery of the outer ring 10, and the large-diameter portion 61A is disposed on a portion of the outer periphery of the small-diameter portion 62A. The inner diameter of the small-diameter portion 62A is approximately equal to the outer diameter of the outer ring 10, and its length in the direction of the rotation axis m is approximately equal to the length in the direction of the rotation axis m of the outer ring 10. The inner diameter of the large-diameter portion 61A is approximately equal to the outer diameter of the small-diameter portion 62A, and its length in the direction of the rotation axis m is shorter than that of the small-diameter portion 62A in the direction of the rotation axis m.

[0124] The large-diameter portion 61A and the small-diameter portion 62A are integrated, for example, by pressing or bonding, to form a bearing cage 60A with a shape substantially the same as the bearing cage 60. In the bearing cage 60A, the portion of the large-diameter portion 61A stacked on the outer peripheral surface of the small-diameter portion 62A is a thick-walled portion, while the portion consisting only of the small-diameter portion 62A is a thin-walled portion. A strain gauge 100 is disposed on the outer peripheral surface of the small-diameter portion 62A, which is the thin-walled portion, via an adhesive layer.

[0125] Thus, the bearing cage is not limited to being integrally formed; it can also be formed by joining different components, for example, by joining different components with different diameters together. In this case, by placing a strain gauge 100 in the thin-walled portion, the strain of the outer ring 10 can also be detected through the thin-walled portion, which serves as a strain transmission part. Furthermore, the strain can be detected in the region D of the thick-walled portion at least on the outer peripheral surface of the outer ring 10. O (Refer to Figure 3 The configuration, where the components are joined together, ensures the rigidity of the shaft into the rolling bearing cage unit 1A. It should be noted that this is not limited to a single-piece molding; different components can be joined together. This also applies to the bearing cage example described later.

[0126] Figure 11 This is a cross-sectional view of a rolling bearing cage unit, illustrating a variation of the first embodiment, shown in the example of embodiment 2. Figure 2The section corresponding to (b). For example... Figure 11 As shown, the rolling bearing cage unit 1B differs from the rolling bearing cage unit 1 (refer to) in that the bearing cage 60 is replaced by the bearing cage 60B. Figure 2 (etc.) are different.

[0127] The bearing cage 60B has a cylindrical thick-walled portion 61B and a cylindrical thin-walled portion 62B with a radial thickness thinner than the thick-walled portion 61B. The inner diameter of the thick-walled portion 61B is approximately equal to the outer diameter of the outer ring 10, and its length in the direction of the rotation axis m is approximately equal to the length in the direction of the rotation axis m of the outer ring 10. That is, the thick-walled portion 61B is configured to be in contact with the entire outer peripheral surface of the outer ring 10.

[0128] The inner diameter of the thin-walled portion 62B is approximately equal to the outer diameter of the outer ring 10, and it protrudes from the end face of the thick-walled portion 61B on the preload side, near the rotation axis m, in a direction approximately parallel to the rotation axis m. The thick-walled portion 61B and the thin-walled portion 62B are, for example, integrally formed. A strain gauge 100 is disposed on the outer peripheral surface of the thin-walled portion 62B via an adhesive layer. It should be noted that although in Figure 11 An example is shown where the thin-walled portion 62B protrudes from the end face of the thick-walled portion 61B on the preload side, but it can also protrude from the end face on the opposite side of the preload side. Since strain is easily transmitted when it protrudes from the end face on the preload side, it is preferable that the thin-walled portion 62B protrudes from the end face on the preload side.

[0129] Thus, the length of the thick-walled portion 61B along the rotation axis m is approximately equal to the length of the outer ring 10 along the rotation axis m, and the thin-walled portion 62B can protrude from the end face of the thick-walled portion 61B near the rotation axis m in a direction approximately parallel to the rotation axis m. In this case, by placing a strain gauge 100 on the thin-walled portion, the strain of the outer ring 10 can be detected through the thin-walled portion, which serves as a strain transmission unit. Furthermore, since the thick-walled portion can be configured to be in contact with the entire outer peripheral surface of the outer ring 10, the rigidity of the shaft inserted into the rolling bearing cage unit 1B can be sufficiently guaranteed.

[0130] Figure 12 This is a cross-sectional view of a rolling bearing cage unit, exemplified by a variation of the first embodiment, showing a design similar to... Figure 2 The section corresponding to (b). For example... Figure 12 As shown in the bearing cage 60C of the rolling bearing cage unit 1C, the thin-walled portion 62C can be configured to protrude from the end face of the thick-walled portion 61C on the preload side in a direction approximately parallel to the rotation axis m, further from the rotation axis m. In this case, it also functions similarly to... Figure 11 The same effect as in the case of [the previous situation].

[0131] Figure 13This is a cross-sectional view of a rolling bearing cage unit, exemplified by Variation 4 of the first embodiment, showing a design similar to... Figure 2 The section corresponding to (b). For example... Figure 13 As shown, the rolling bearing cage unit 1D differs from the rolling bearing cage unit 1 (refer to...) in that the bearing cage 60 is replaced by the bearing cage 60D. Figure 2 (etc.) are different.

[0132] The bearing cage 60D has a cylindrical thick-walled portion 61D and a cylindrical thin-walled portion 62D with a thickness thinner than the thick-walled portion 61D. The inner diameter of the thick-walled portion 61D is approximately equal to the outer diameter of the outer ring 10, and its length in the direction of the rotation axis m is approximately equal to the length in the direction of the rotation axis m of the outer ring 10. That is, the thick-walled portion 61D is configured to be in contact with the entire outer peripheral surface of the outer ring 10.

[0133] The thin-walled portion 62D extends from the end face of the thick-walled portion 61D on the preload side in a direction substantially perpendicular to the rotation axis m, and is arranged in a ring-shaped connection with a portion of the end face of the outer ring 10. The thickness of the thin-walled portion 62D in the rotation axis m direction is thinner than the radial thickness of the thick-walled portion 61D. The thick-walled portion 61D and the thin-walled portion 62D are integrally formed, for example. A strain gauge 100 is disposed on the surface of the thin-walled portion 62D opposite to the end face of the outer ring 10 via an adhesive layer.

[0134] Thus, the thin-walled portion of the bearing cage can be configured to contact the end face of the outer ring 10. In this case, by configuring a strain gauge 100 on the thin-walled portion, the strain of the outer ring 10 can also be detected through the thin-walled portion, which serves as a strain transmission unit. Furthermore, since the thick-walled portion can be configured to contact the entire outer peripheral surface of the outer ring 10, the rigidity of the shaft inserted into the rolling bearing cage unit 1D can be sufficiently guaranteed.

[0135] <Second Implementation Method>

[0136] In the second embodiment, an example of a bearing cage mounted on the inner circumferential surface of the inner ring is shown. It should be noted that in the second embodiment, descriptions of components identical to those in the already described embodiments are sometimes omitted.

[0137] Figure 14 This is a cross-sectional view illustrating a rolling bearing cage unit according to an example of a second embodiment, showing a configuration similar to... Figure 2 The section corresponding to (b). For example... Figure 14 As shown, the rolling bearing cage unit 5 differs from the rolling bearing cage unit 1 (refer to) in that the bearing cage 60 is replaced by the bearing cage 70. Figure 2 (etc.) are different.

[0138] The bearing cage 70 is disposed on the inner circumferential side of the inner ring 20, pressing against the inner circumferential surface of the inner ring 20 throughout its entire circumference. The bearing cage 70 may be pressed into the inner ring 20, for example. Alternatively, the bearing cage 70 may be bonded to the inner ring 20.

[0139] The bearing cage 70 has a cylindrical thick-walled portion 71 and a cylindrical thin-walled portion 72 with a radial thickness thinner than the thick-walled portion 71. The length of the bearing cage 70 along the rotation axis m is approximately equal to the length of the inner ring 20 along the rotation axis m. The outer diameter of both the thick-walled portion 71 and the thin-walled portion 72 is approximately equal to the inner diameter of the inner ring 20, and they are adjacent in the rotation axis m direction. The thick-walled portion 71 and the thin-walled portion 72 are, for example, integrally formed.

[0140] In this embodiment, the thicknesses of the thick-walled portion 71 and the thin-walled portion 72 are approximately constant. The thin-walled portion 72 is a strain transmission portion that transmits the strain generated in the inner ring 20 during the rotation of the rolling element 30 to the strain gauge 100. The strain gauge 100 is disposed on the thin-walled portion 72 via an adhesive layer.

[0141] exist Figure 14 C I It is the intersection of the extension of line A in the sectional view and the inner circumferential surface of inner circle 20. (D) I It is the self-intersection point C in the sectional view I The intersection point C of the inner circle 20 I The area of ​​the inner circumferential surface of the inner ring 20, which is the closer end face, i.e., the preload side end face. Area D I This is the region where the displacement of the rolling element 30 is relatively large during rotation.

[0142] Thus, the thin-walled portion of the bearing cage can be configured to contact the inner circumferential surface of the inner ring 20. In this case, by configuring a strain gauge 100 on the thin-walled portion, the strain of the inner ring 20 can also be detected through the thin-walled portion, which serves as a strain transmission unit. Furthermore, the thick-walled portion, in a region D at least contacting the inner circumferential surface of the inner ring 20... I The connection method is configured to ensure the rigidity of the shaft of the inserted rolling bearing cage unit 5.

[0143] <Modifications of the Second Embodiment>

[0144] In Variation 1 of the second embodiment, another example of a bearing cage mounted on the inner circumferential surface of the inner ring is shown. It should be noted that, for Variation 1 of the second embodiment, descriptions of components identical to those in the already described embodiments are sometimes omitted.

[0145] Figure 15 This is a cross-sectional view of a rolling bearing cage unit, illustrating a variation of the second embodiment 1, showing a design similar to... Figure 2 The section corresponding to (b). For example... Figure 15As shown, the rolling bearing cage unit 5A differs from the rolling bearing cage unit 5 (refer to) in that the bearing cage 70 is replaced by the bearing cage 70A. Figure 14 (etc.) are different.

[0146] The bearing cage 70A has a cylindrical small-diameter portion 71A and a cylindrical large-diameter portion 72A. The large-diameter portion 72A is integrally disposed on the inner circumferential side of the inner ring 20, and the small-diameter portion 71A is disposed on a portion of the inner circumferential side of the large-diameter portion 72A. For the large-diameter portion 72A, its outer diameter is approximately equal to the inner diameter of the inner ring 20, and its length in the direction of its rotation axis m is approximately equal to the length in the direction of the rotation axis m of the inner ring 20. For the small-diameter portion 71A, its outer diameter is approximately equal to the inner diameter of the large-diameter portion 72A, and its length in the direction of its rotation axis m is shorter than the length in the direction of the rotation axis m of the large-diameter portion 72A.

[0147] The small-diameter portion 71A and the large-diameter portion 72A are integrated, for example, by pressing or bonding, to form a bearing cage 70A with a shape substantially the same as the bearing cage 70. In the bearing cage 70A, the portion on the inner circumferential surface of the large-diameter portion 72A where the small-diameter portion 71A is stacked is a thick-walled portion, while the portion consisting solely of the large-diameter portion 72A is a thin-walled portion. A strain gauge 100 is disposed on the inner circumferential surface of the large-diameter portion 72A, which is the thin-walled portion, via an adhesive layer.

[0148] Thus, the bearing cage is not limited to being integrally formed; different components can also be joined together. In this case, by placing a strain gauge 100 in the thin-walled portion, the strain of the inner ring 20 can also be detected through the thin-walled portion, which serves as a strain transmission part. Furthermore, the thick-walled portion extends to at least the region D of the inner circumferential surface of the inner ring 20. I (Refer to Figure 14 The arrangement of the components ensures the rigidity of the shaft into which the rolling bearing cage unit 5A is inserted. It should be noted that this is not limited to a single-piece molding; different components can also be joined together. This principle also applies to the bearing cage example described later.

[0149] Figure 16 This is a cross-sectional view of a rolling bearing cage unit, illustrating a variation of the second embodiment, shown in the example of embodiment 2. Figure 2 The section corresponding to (b). For example... Figure 16 As shown, the rolling bearing cage unit 5B differs from the rolling bearing cage unit 5 (refer to) in that the bearing cage 70 is replaced by the bearing cage 70B. Figure 14 (etc.) are different.

[0150] The bearing cage 70B has a cylindrical thick-walled portion 71B and a cylindrical thin-walled portion 72B with a radial thickness thinner than the thick-walled portion 71B. The outer diameter of the thick-walled portion 71B is approximately equal to the inner diameter of the inner ring 20, and its length in the direction of its rotation axis m is approximately equal to the length in the direction of the rotation axis m of the inner ring 20. That is, the thick-walled portion 71B is configured to be in contact with the entire inner circumferential surface of the inner ring 20.

[0151] The outer diameter of the thin-walled portion 72B is approximately equal to the inner diameter of the inner ring 20, and it protrudes from the end face of the thick-walled portion 71B on the preload side, at a distance from the rotation axis m, in a direction approximately parallel to the rotation axis m. The thick-walled portion 71B and the thin-walled portion 72B are integrally formed, for example. A strain gauge 100 is disposed on the inner circumferential surface of the thin-walled portion 72B via an adhesive layer.

[0152] Thus, the thin-walled portion of the bearing cage can protrude from the end face of the inner ring 20. In this case, by placing a strain gauge 100 on the thin-walled portion, the strain of the inner ring 20 can also be detected through the thin-walled portion, which serves as a strain transmission part. In addition, the thick-walled portion can be arranged in such a way that it is in contact with the entire inner circumferential surface of the inner ring 20, thereby ensuring sufficient rigidity of the shaft inserted into the rolling bearing cage unit 5B.

[0153] Figure 17 This is a cross-sectional view of a rolling bearing cage unit, exemplified by a variation of the second embodiment, showing a design similar to... Figure 2 The section corresponding to (b). For example... Figure 17 As shown in the bearing cage 70C of the rolling bearing cage unit 5C, the thin-walled portion 72C can be configured to protrude from the end face of the thick-walled portion 71C on the preload side in a direction approximately parallel to the rotation axis m. In this case, it also functions as... Figure 16 The same effect as in the case of [the previous situation].

[0154] Figure 18 This is a cross-sectional view of a rolling bearing cage unit, as exemplified by Variation 4 of the second embodiment, showing a design similar to... Figure 2 The section corresponding to (b). For example... Figure 18 As shown, the rolling bearing cage unit 5D differs from the rolling bearing cage unit 5 (refer to) in that the bearing cage 70 is replaced by the bearing cage 70D. Figure 14 (etc.) are different.

[0155] The bearing cage 70D has a cylindrical thick-walled portion 71D and a cylindrical thin-walled portion 72D with a thickness thinner than the thick-walled portion 71D. The outer diameter of the thick-walled portion 71D is approximately equal to the inner diameter of the inner ring 20, and its length in the direction of its rotation axis m is approximately equal to the length in the direction of the rotation axis m of the inner ring 20. That is, the thick-walled portion 71D is configured to be in contact with the entire inner circumferential surface of the inner ring 20.

[0156] The thin-walled portion 72D is configured to extend from the end face of the thick-walled portion 71D on the preload side in a direction substantially perpendicular to the rotation axis m, and is annularly connected to a portion of the end face of the inner ring 20. The thickness of the thin-walled portion 72D in the direction of the rotation axis m is thinner than the radial thickness of the thick-walled portion 71D. The thick-walled portion 71D and the thin-walled portion 72D are integrally formed, for example. A strain gauge 100 is disposed on the surface of the thin-walled portion 72D opposite to the end face of the inner ring 20 via an adhesive layer.

[0157] Thus, the thin-walled portion of the bearing cage can be configured to contact the end face of the inner ring 20. In this case, by configuring a strain gauge 100 on the thin-walled portion, the strain of the inner ring 20 can also be detected through the thin-walled portion, which serves as a strain transmission unit. Furthermore, since the thick-walled portion can be configured to contact the entire inner circumferential surface of the inner ring 20, the rigidity of the shaft inserted into the rolling bearing cage unit 5D can be sufficiently guaranteed.

[0158] <Third Implementation Method>

[0159] In the third embodiment, an example of a bearing cage is shown where the thin-walled portion is provided locally rather than circumferentially. It should be noted that in the third embodiment, descriptions of components identical to those in the already described embodiments are sometimes omitted.

[0160] Figure 19 This is a perspective view illustrating a rolling bearing cage unit according to a third embodiment. Figure 19 As shown, the rolling bearing cage unit 6 differs from the rolling bearing cage unit 1 (refer to) in that the bearing cage 60 is replaced by the bearing cage 80. Figure 2 (etc.) are different.

[0161] The bearing cage 80 is disposed on the outer circumference of the outer ring 10, pressing against the outer circumference of the outer ring 10. The bearing cage 80 may be pressed into the outer ring 10, for example. Alternatively, the bearing cage 80 may be bonded to the outer ring 10.

[0162] The bearing cage 80 is a cylindrical component whose length along the rotation axis m is approximately equal to the length along the rotation axis m of the outer ring 10, and whose inner diameter is approximately equal to the outer diameter of the outer ring 10. A recess is provided on the outer circumferential surface of the bearing cage 80. In the bearing cage 80, the portion outside the recess is a thick-walled portion 81, and the portion inside the recess is a thin-walled portion 82. That is, in the bearing cage 80, the thick-walled portion 81 is cylindrical, and the thin-walled portion 82 is the recess provided within the thick-walled portion 81.

[0163] The thin-walled section 82 is a strain transmission section that transmits the strain generated on the outer ring 10 when the rolling element 30 rotates to the strain gauge 100. The strain gauge 100 is disposed on the thin-walled section 82 through an adhesive layer.

[0164] Thus, a thin-walled recess can be provided on the outer periphery of the bearing cage, and a strain gauge can be disposed within the recess. In this case, the strain of the outer ring 10 can also be detected through the thin-walled portion, which serves as a strain transmission part. Furthermore, the thick-walled portion extends to at least the region D of the outer peripheral surface of the outer ring 10. O (Refer to Figure 3 The arrangement of the two parts ensures the rigidity of the shaft into which the rolling bearing cage unit 6 is inserted. It should be noted that in variations of the first embodiment, the second embodiment, and the second embodiment, the thin-walled portion may not be circumferential but may be partially recessed.

[0165] <Fourth Implementation Method>

[0166] In the fourth embodiment, an example of a rolling bearing cage unit including two rolling bearings is shown. It should be noted that in the fourth embodiment, descriptions of components identical to those in the already described embodiments are sometimes omitted.

[0167] Figure 20 This is a cross-sectional view (1) illustrating a rolling bearing cage unit according to a fourth embodiment. Figure 20 The rolling bearing cage unit 7 shown has two rolling bearings 2, a bearing cage 90, and a strain gauge 100. However, a strain gauge 100 can be provided for each rolling bearing 2 separately.

[0168] In the rolling bearing cage unit 7, two rolling bearings 2 are spaced apart by a predetermined interval with their respective rotation axes m aligned, and are arranged such that their preload side end faces face each other. This arrangement is consistent with... Figure 5 Similarly, the pre-compression direction is the back-side combination (DB).

[0169] The bearing cage 90 includes a thick-walled portion 91 and thin-walled portions 92 disposed on both sides of the thick-walled portion 91 in the direction of the rotation axis m. The thick-walled portion 91 is positioned at least in relation to the region D of each rolling bearing 2. O The connection method is configured such that the portion of the thick-walled part 91 that connects with one rolling bearing 2 is integrated with the portion that extends to the side of another rolling bearing 2 and connects with another rolling bearing 2.

[0170] Figure 21 This is a cross-sectional view (2) illustrating a rolling bearing cage unit according to an example of the fourth embodiment. Figure 21The shown rolling bearing cage unit 7A has two rolling bearings 2, a bearing cage 90A, and a strain gauge 100. However, the strain gauge 100 can be provided for each rolling bearing 2 separately.

[0171] In the rolling bearing cage unit 7A, two rolling bearings 2 are spaced apart by a predetermined interval with their respective rotation axes m aligned, and are configured such that their preload side end faces face outwards from each other. This configuration is consistent with... Figure 6 Similarly, the pre-compression direction is the front combination (DF).

[0172] The bearing cage 90A includes a thin-walled portion 92A and thick-walled portions 91A disposed on both sides of the thin-walled portion 92A in the direction of the rotation axis m. The thick-walled portions 91A are positioned at least in relation to the region D of each rolling bearing 2. O The connection method is configured such that the portion of the thin-walled section 92A that connects with one rolling bearing 2 is integrated with the portion that extends to the side of another rolling bearing 2 and connects with another rolling bearing 2.

[0173] Thus, a bearing cage can be provided for two rolling bearings. In this case, the strain of the outer ring 10 can also be detected by the thin-walled portion, which serves as a strain transfer section. Furthermore, the thick-walled portion extends to at least the region D of the outer peripheral surface of each rolling bearing's outer ring 10. O The connection method ensures the rigidity of the shaft inserted into the rolling bearing cage unit. It should be noted that the description in this embodiment can also be applied to other embodiments and variations.

[0174] While the preferred embodiments have been described in detail above, they are not limited to the embodiments described above. Various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0175] For example, the thick-walled portion and the thin-walled portion are not limited to a cylindrical shape and can be set to any shape. For example, the thick-walled portion and the thin-walled portion can be polygonal in cross-section. For the thick-walled portion, any shape can be adopted within the range that does not affect the rigidity of the shaft, and for the thin-walled portion, any shape can be used as long as it ensures that the required output thickness can be obtained.

[0176] This international application claims priority to Japanese Patent Application No. 2020-131006, filed on July 31, 2020, and the entire contents of Japanese Patent Application No. 2020-131006 are incorporated herein by reference.

[0177] Explanation of reference numerals in the attached figures

[0178] 1. Rolling bearing cage unit (1A-1D), 5. Rolling bearing (5A-5D), 6. Rolling bearing (7A-7A), 2. Rolling bearing, 10. Outer ring, 20. Inner ring, 30. Rolling element, 40. Retainer, 50. Rail, 51. Seal, 52. Seal, 60. Rolling bearing cage (60A-60D), 70. Rolling bearing cage (70A-70D), 80. Bearing cage (61B-61D), 71. Rolling bearing cage (71B-71D), 81. Thick-walled section, 61A. Rolling bearing cage (72A-71A), 62. Rolling bearing cage (72B-62D), 72. Rolling bearing cage (72B-72D), 82. Thin-walled section, 100. Strain gauge, 101. Substrate, 101a. Upper surface, 102. Functional layer, 103. Resistor, 104. Wiring, 105. Terminal section, 106. Cover layer

Claims

1. A rolling bearing cage unit, comprising: A rolling bearing includes an outer ring, an inner ring coaxially arranged on the inner circumferential side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and has a predetermined axis of rotation. A bearing cage, which is configured to contact the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and A strain gauge, comprising a resistive element for detecting the strain of the outer or inner ring. The aforementioned bearing cage includes a thick-walled portion and a thin-walled portion with a thickness thinner than the thick-walled portion. The aforementioned bearing cage is configured to press against the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring throughout the entire circumference. The aforementioned thin-walled portion is a strain transmission section of the strain gauge that transmits the strain generated in the outer or inner ring during the rotation of the rolling element to the strain transmission section of the strain gauge, and is configured to be in contact with a portion of the end face of the outer or inner ring. The aforementioned thin-walled portion and the aforementioned thick-walled portion are positioned in a way that does not overlap when viewed from above. The strain gauge is disposed in the thin-walled portion. A preload of a specified contact angle is applied to the aforementioned rolling bearing. The aforementioned thick-walled portion is configured to connect at least with the region of the preload side end face of the outer ring or the inner ring, which is the end face of the outer ring or the inner ring that is closer to the intersection point of the straight line showing the aforementioned contact angle and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The length of the aforementioned thick-walled portion along the rotation axis is approximately equal to the length of the aforementioned outer ring and the aforementioned inner ring along the rotation axis. The aforementioned thick-walled portion is configured to be in contact with the entire surface of the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring.

2. The rolling bearing cage unit according to claim 1, wherein, The aforementioned thin-walled portion is configured to extend from the end face of the aforementioned thick-walled portion in a direction substantially perpendicular to the aforementioned axis of rotation, and to connect with a portion of the end face of the aforementioned outer ring or the aforementioned inner ring. The thickness of the thin-walled portion in the direction of the rotation axis is thinner than the radial thickness of the thick-walled portion.

3. The rolling bearing cage unit according to claim 1 or 2, wherein, The aforementioned thick-walled portion and the aforementioned thin-walled portion are cylindrical.

4. The rolling bearing cage unit according to claim 3, wherein, The aforementioned bearing cage is formed by joining different components of different diameters together.

5. A rolling bearing cage unit, comprising: A rolling bearing includes an outer ring, an inner ring coaxially arranged on the inner circumferential side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and has a predetermined axis of rotation. A bearing cage, which is configured to contact the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and A strain gauge, comprising a resistive element for detecting the strain of the outer or inner ring. The aforementioned bearing cage includes a thick-walled portion and a thin-walled portion with a thickness thinner than the thick-walled portion. The aforementioned bearing cage is configured to press against the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring throughout the entire circumference. The aforementioned thin-walled portion is used to transmit the strain generated in the outer ring or the inner ring during the rotation of the rolling element to the strain transmission part of the strain gauge, and is arranged in contact with the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The aforementioned thin-walled portion and the aforementioned thick-walled portion are positioned in a way that does not overlap when viewed from above. The strain gauge is disposed in the thin-walled portion. A preload of a specified contact angle is applied to the aforementioned rolling bearing. The aforementioned thick-walled portion is configured to connect at least with the region of the preload side end face of the outer ring or the inner ring, which is the end face of the outer ring or the inner ring that is closer to the intersection point of the straight line showing the aforementioned contact angle and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The above-mentioned rolling bearings are provided in two parts. The two aforementioned rolling bearings are configured to be spaced apart by a predetermined interval with their respective axes of rotation aligned, and the preloaded end faces are opposite each other. A bearing cage is provided for both of the above rolling bearings. The aforementioned thick-walled portions are configured to at least contact the aforementioned regions of their respective rolling bearings. The portion of the thick-walled section that connects with one of the aforementioned rolling bearings is integrated with the portion that extends to the side of the other of the aforementioned rolling bearings and connects with the other of the aforementioned rolling bearings.

6. A rolling bearing cage unit, comprising: A rolling bearing includes an outer ring, an inner ring coaxially arranged on the inner circumferential side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and has a predetermined axis of rotation. A bearing cage, which is configured to contact the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and A strain gauge, comprising a resistive element for detecting the strain of the outer or inner ring. The aforementioned bearing cage includes a thick-walled portion and a thin-walled portion with a thickness thinner than the thick-walled portion. The aforementioned bearing cage is configured to press against the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring throughout the entire circumference. The aforementioned thin-walled portion is used to transmit the strain generated in the outer ring or the inner ring during the rotation of the rolling element to the strain transmission part of the strain gauge, and is arranged in contact with the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The aforementioned thin-walled portion and the aforementioned thick-walled portion are positioned in a way that does not overlap when viewed from above. The strain gauge is disposed in the thin-walled portion. A preload of a specified contact angle is applied to the aforementioned rolling bearing. The aforementioned thick-walled portion is configured to connect at least with the region of the preload side end face of the outer ring or the inner ring, which is the end face of the outer ring or the inner ring that is closer to the intersection point of the straight line showing the aforementioned contact angle and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The above-mentioned rolling bearings are provided in two parts. The two aforementioned rolling bearings are configured to be spaced apart by a predetermined interval with their respective axes of rotation aligned, and the preloaded end faces of the bearings face outwards from each other. A bearing cage is provided for both of the above rolling bearings. The aforementioned thick-walled portions are configured to at least contact the aforementioned regions of their respective rolling bearings. The portion of the thin-walled section that connects with one of the aforementioned rolling bearings is integrated with the portion that extends to the side of the other aforementioned rolling bearing and connects with the other aforementioned rolling bearing.

7. A rolling bearing cage unit, comprising: A rolling bearing includes an outer ring, an inner ring coaxially arranged on the inner circumferential side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and has a predetermined axis of rotation. A bearing cage, which is configured to contact the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and A strain gauge, comprising a resistive element for detecting the strain of the outer or inner ring. The aforementioned bearing cage includes a thick-walled portion and a thin-walled portion with a thickness thinner than the thick-walled portion. The aforementioned bearing cage is configured to press against the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring throughout the entire circumference. The aforementioned thin-walled portion transmits the strain generated in the outer or inner ring during the rotation of the rolling element to the strain transmission section of the strain gauge, and is configured to be in contact with the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring, or with a portion of the end face of the outer or inner ring. The aforementioned thin-walled portion and the aforementioned thick-walled portion are positioned in a way that does not overlap when viewed from above. The strain gauge is disposed in the thin-walled portion. A preload of a specified contact angle is applied to the aforementioned rolling bearing. The aforementioned thick-walled portion is configured to connect at least with the region of the preload side end face of the outer ring or the inner ring, which is the end face of the outer ring or the inner ring that is closer to the intersection point of the straight line showing the aforementioned contact angle and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The outer diameter of the aforementioned outer ring is less than 30mm.

8. The rolling bearing cage unit according to claim 7, wherein, The aforementioned resistive element is formed from a Cr mixed-phase film.

9. The rolling bearing cage unit according to claim 7 or 8, wherein, The length of the aforementioned thick-walled portion in the direction of the rotation axis is shorter than the length of the aforementioned outer ring and the aforementioned inner ring in the direction of the rotation axis.

10. The rolling bearing cage unit according to claim 7 or 8, wherein, The thick-walled portion is cylindrical, and the thin-walled portion is a recess provided in the thick-walled portion.

11. A rolling bearing cage unit, comprising: A rolling bearing includes an outer ring, an inner ring coaxially arranged on the inner circumferential side of the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and has a predetermined axis of rotation. A bearing cage, which is configured to contact the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the rolling bearing; and A strain gauge, comprising a resistive element for detecting the strain of the outer or inner ring. The aforementioned bearing cage includes a thick-walled portion and a thin-walled portion with a thickness thinner than the thick-walled portion, wherein the thin-walled portion and the thick-walled portion are arranged in a position that does not overlap when viewed from above. The strain gauge is disposed in the thin-walled portion. A preload of a specified contact angle is applied to the aforementioned rolling bearing. The aforementioned thick-walled portion is configured to connect at least with the region of the preload side end face of the outer ring or the inner ring, which is the end face of the outer ring or the inner ring that is closer to the intersection point of the straight line showing the aforementioned contact angle and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring. The aforementioned bearing cage is configured to press against the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring throughout the entire circumference. The aforementioned thin-walled portion is a strain transmission section of the strain gauge that transmits the strain generated in the outer ring or the inner ring when the rolling element rotates to the strain transmission section of the strain gauge, and is arranged in contact with the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring.

12. The rolling bearing cage unit according to claim 11, wherein, The strain gauge is positioned on the thin-walled portion near the thick-walled portion, and the end of the strain gauge on the thick-walled portion side is configured to abut against the end face of the thin-walled portion side of the thick-walled portion.

13. The rolling bearing cage unit according to claim 11, wherein, The thickness of the thick-walled portion is more than 10 times the bending rigidity of the thin-walled portion.

14. The rolling bearing cage unit according to claim 11, wherein, The measuring length of the strain gauge is smaller than the distance between adjacent rolling elements of the rolling bearing.

15. The rolling bearing cage unit according to claim 11, wherein, The strain gauge has a substrate and a functional layer formed on the upper surface of the substrate as the lower layer of the resistive element, and the resistive element is a Cr mixed-phase film containing 80% by weight or more of α-Cr.

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