Magnetostrictive torque sensor and method for manufacturing the same

Abstract

To provide a magnetostrictive torque sensor and a manufacturing method thereof which can improve productivity compared to the case of configuring a magnetostrictive torque sensor by bonding and fixing a flexible substrate on which a plurality of coils are formed to a hollow cylindrical magnetic ring.SOLUTION: A magnetostrictive torque sensor 1 for detecting torque applied to a rotating shaft 8 having a magnetostrictive effect, includes: a support member 2 having an inner cylindrical portion 21 through which the rotating shaft 8 is inserted; a flexible substrate 5 arranged on the outer circumference of the inner cylindrical portion 21 and having a plurality of coils 511 to 519, 521 to 529, 531 to 539, and 541 to 549 formed by wiring patterns; and a heat-shrinkable tube 6 for tightening the flexible substrate 5 toward an outer peripheral surface 21b of the inner cylindrical portion 21. When manufacturing the magnetostrictive torque sensor 1, the heat-shrinkable tube 6 is placed around the outer periphery of the flexible substrate 5, and the flexible substrate 5 is tightened to the inner cylindrical portion 21 by shrinking the heat-shrinkable tube 6 by heating.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a magnetostrictive torque sensor and a method for manufacturing a magnetostrictive torque sensor. [Background technology]

[0002] Conventionally, magnetostrictive torque sensors have been used to detect the torque of the output rotating shaft of an automobile engine, for example. Magnetostrictive torque sensors are configured to detect the torque applied to the rotating shaft based on the change in inductance of a detection coil arranged around the rotating shaft, utilizing the magnetostrictive effect, in which the magnetic permeability of the rotating shaft changes due to stress. The present applicant has proposed a magnetostrictive torque sensor in which a flexible substrate on which multiple detection coils are formed is arranged around the rotating shaft, and the torque applied to the rotating shaft is detected based on the change in inductance of the multiple detection coils (see Patent Document 1).

[0003] The magnetostrictive torque sensor described in Patent Document 1 has a flexible substrate on which are formed a plurality of first detection coils having first linear portions inclined at +45 degrees to the axial direction of the rotating shaft and a plurality of second detection coils having second linear portions inclined at -45 degrees to the axial direction of the rotating shaft, and a hollow cylindrical magnetic ring made of a ferromagnetic material arranged coaxially around the flexible substrate. The flexible substrate is adhesively fixed to the inner peripheral surface of the magnetic ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-49124 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the magnetostrictive torque sensor described in Patent Document 1, as described above, a flexible substrate is adhesively fixed to the inner surface of a hollow cylindrical magnetic ring during manufacture, so it is necessary to wait until the adhesive applied to the inner surface of the magnetic ring or to one side of the flexible substrate facing the inner surface of the magnetic ring hardens, which is an obstacle to improving productivity.

[0006] Therefore, an object of the present invention is to provide a magnetostrictive torque sensor and a manufacturing method thereof that can improve productivity compared to a case in which a magnetostrictive torque sensor is constructed by adhesively fixing a flexible substrate on which multiple coils are formed to a hollow cylindrical magnetic ring. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a magnetostrictive torque sensor that is attached around a rotating shaft having a magnetostrictive effect and detects torque applied to the rotating shaft, the magnetostrictive torque sensor comprising: a support member having a cylindrical portion through which the rotating shaft is inserted; a flexible substrate that is arranged on the outer periphery of the cylindrical portion and has a plurality of coils formed by a wiring pattern; and a fastening member that fastens the flexible substrate toward the outer periphery of the cylindrical portion.

[0008] Furthermore, in order to solve the above-mentioned problems, the present invention provides a method for manufacturing the above-mentioned magnetostrictive torque sensor, in which the fastening member is a cylindrical heat-shrinkable tube that shrinks when heated, the method comprising: an arrangement step of arranging the flexible substrate on the outer periphery of the cylindrical portion of the support member and arranging the heat-shrinkable tube on the outer periphery of the flexible substrate; and a fastening step of heating and shrinking the heat-shrinkable tube, and fastening the flexible substrate toward the outer periphery of the cylindrical portion. Effect of the Invention

[0009] According to the magnetostrictive torque sensor and the manufacturing method of the magnetostrictive torque sensor of the present invention, it is possible to improve productivity compared to a case in which a magnetostrictive torque sensor is constructed by adhesively fixing a flexible substrate on which a plurality of coils are formed to a hollow cylindrical magnetic ring. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a magnetostrictive torque sensor according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view of the magnetostrictive torque sensor taken along line AA in FIG. [Diagram 3] FIG. 2 is an enlarged cross-sectional view showing a portion of the magnetostrictive torque sensor. [Figure 4] FIG. [Diagram 5] 11 is a configuration diagram showing a state in which a flexible board and a cable are combined with a support member as viewed in the axial direction. FIG. [Figure 6] FIG. 2 is a plan view of a flexible substrate. [Figure 7] FIG. 2 is a cross-sectional view of a flexible substrate. [Figure 8] 1A to 1D are plan views showing wiring patterns of first to fourth wiring layers of a flexible substrate. [Figure 9] 1 is a circuit diagram illustrating a schematic configuration example of an electric circuit including a flexible substrate, a cable, an oscillator, and a voltmeter. [Figure 10] FIG. 2 is a perspective view showing a support member, a flexible substrate, and a heat shrink tube. [Figure 11] FIG. 13 is a perspective view showing a state in which the arrangement process is completed. [Figure 12] FIG. 11 is a perspective view showing a completed state of the fastening process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment Mode] Fig. 1 is a perspective view showing a magnetostrictive torque sensor according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing a cross section of the magnetostrictive torque sensor taken along line AA in Fig. 1 together with a rotating shaft on which torque is to be detected. Fig. 3 is a cross-sectional view showing an enlarged portion of the magnetostrictive torque sensor.

[0012] This magnetostrictive torque sensor 1 is attached around a rotating shaft 8 and is used to detect the torque applied to the rotating shaft 8. The rotating shaft 8 is a shaft that transmits the driving force of a driving source such as an automobile engine. The torque detection result obtained by the magnetostrictive torque sensor 1 is used to control the driving source, an automatic transmission, etc.

[0013] The magnetostrictive torque sensor 1 includes a support member 2 having an inner cylindrical portion 21 through which a rotating shaft 8 is inserted at the center, a cover member 3 having an outer cylindrical portion 31 arranged on the outer periphery of the inner cylindrical portion 21 of the support member 2, a sealing member 4 made of molded resin molded to cover at least a portion of each of the support member 2 and the cover member 3, a flexible substrate 5 arranged on the outer periphery of the inner cylindrical portion 21 of the support member 2, a heat shrink tube 6 as a fastening member that fastens the flexible substrate 5 toward the outer periphery 21b of the inner cylindrical portion 21 of the support member 2, and a cable 7 having a plurality of electric wires connected to the flexible substrate 5. The support member 2 and the cover member 3 are injection-molded resin members, and together with the sealing member 4, form a resin housing 10.

[0014] The rotating shaft 8 is a ferromagnetic body having a magnetostrictive effect, and rotates around the rotation axis O to transmit torque. Here, magnetostriction is a phenomenon in which a distortion (distortion) appears in the shape when a magnetic field is applied to a ferromagnetic body to magnetize it. This phenomenon can be used in reverse to detect the magnetic field generated by the distortion of the shape with the magnetostrictive torque sensor 1, thereby detecting the torque applied to the rotating shaft 8. As the rotating shaft 8, for example, a shaft-shaped body made of chromium steel containing chromium, such as chromium steel, chromium molybdenum steel, or nickel chromium molybdenum steel, which is subjected to carburizing, quenching, and tempering treatments and further to shot peening can be suitably used. Hereinafter, the direction parallel to the rotation axis O of the rotating shaft 8 is referred to as the axial direction.

[0015] Fig. 4 is a perspective view showing the support member 2. Fig. 5 is a configuration diagram showing the support member 2 combined with the flexible substrate 5 and the cable 7 as viewed in the axial direction. The cable 7 includes first to fourth electric wires 71 to 74 and a sheath 75 collectively covering the first to fourth electric wires 71 to 74. The first to fourth electric wires 71 to 74 are insulated electric wires in which core wires 711, 721, 731, and 741 made of a metal with good electrical conductivity are covered with insulating coverings 712, 722, 732, and 742 made of an insulator.

[0016] The support member 2 integrally includes an inner cylindrical portion 21, an annular flange portion 22 provided on the outer periphery of one axial end of the inner cylindrical portion 21, a bottom wall portion 23 provided on the outer periphery of the other axial end of the inner cylindrical portion 21 and facing the flange portion 22 in the axial direction, and a cable support portion 24 for supporting the cable 7. The inner cylindrical portion 21 has an inner peripheral surface 21a facing the outer peripheral surface 8a of the rotating shaft 8, and the flexible substrate 5 is in contact with the outer peripheral surface 21b. The inner cylindrical portion 21 corresponds to the "tube portion" of the present invention. As shown in FIG. 3, the flange portion 22 has a trapezoidal cross section along the axial direction, and a protrusion 221 protruding from a part of the trapezoid to the opposite side to the flexible substrate 5. An annular recess 20 is formed between the protrusion 221 and the inner cylindrical portion 21.

[0017] The cable support part 24 is provided so as to protrude radially outward from the other axial end part of the inner cylindrical part 21. The cable support part 24 has first to third wall parts 241-243 which support the first to fourth electric wires 71-74 by dividing them at predetermined intervals, respectively, a sheath holding part 244 which holds the sheath 75, and a base part 245 which supports a protruding piece part 500 (described later) of the flexible substrate 5. The base part 245 is provided with a pair of projections 245a, 245b as fixing parts for fixing the protruding piece part 500.

[0018] The cover member 3 integrally includes an outer cylindrical portion 31, an annular lid portion 32 provided on the inner circumference of one axial end of the outer cylindrical portion 31, and a cable clamping portion 33 that clamps the cable 7 between the outer cylindrical portion 31 and the cable support portion 24 of the support member 2. The other axial end of the outer cylindrical portion 31 is abutted against the bottom wall portion 23 of the support member 2. The outer cylindrical portion 31 forms an annular housing space 100 between the inner cylindrical portion 21 of the support member 2 and the outer cylindrical portion 31, for housing the flexible substrate 5 and the heat shrink tube 6. The inner diameter side end of the lid portion 32 is provided with a protrusion 321 aligned with the flange portion 22 of the support member 2 in the axial direction. The protrusion 321 fits into a recess 20 between the protrusion 221 of the flange portion 22 and the inner cylindrical portion 21.

[0019] The sealing member 4 covers the outer cylindrical portion 31, lid portion 32, and cable clamping portion 33 of the cover member 3, as well as both axial ends, bottom wall portion 23, and cable support portion 24 of the inner cylindrical portion 21 of the support member 2, and prevents the intrusion of moisture and the like into the accommodation space 100. The sealing member 4 is formed by injecting molten liquid molding resin into a mold in which the support member 2 and the cover member 3 are arranged. The molding resin is injected from multiple injection holes provided in a portion of the lid portion 32 of the cover member 3 facing the end face 32a on the side opposite to the accommodation space 100 side.

[0020] As shown in FIG. 1, three injection marks 41-43 of mold resin are formed on the sealing member 4. The injection marks 41-43 are marks left after removing the mold resin remaining in the injection hole of the metal mold. As shown in FIG. 3, a small gap is formed between the support member 2 and the cover member 3, but this gap is formed into a labyrinth shape with a Z-shaped cross section by the engagement of the protrusions 221, 321, so that the molten mold resin is prevented from entering the accommodation space 100 and coming into contact with the flexible substrate 5 and the heat shrink tube 6. In other words, the housing 10 is configured such that the cover member 3 prevents the mold resin from coming into contact with the flexible substrate 5 and the heat shrink tube 6.

[0021] Fig. 6 is a plan view of the flexible substrate 5. Fig. 7 is a cross-sectional view of the flexible substrate 5. The flexible substrate 5 has a strip portion 50 extending in the longitudinal direction (the left-right direction in Fig. 6) and a protruding piece portion 500 extending from the strip portion 50 along a short side direction perpendicular to the longitudinal direction. First to fourth terminal portions 501-504 are provided at the tip of the protruding piece portion 500. Core wires 711, 721, 731, 741 of the first to fourth electric wires 71-74 supported by the cable support portion 24 of the support member 2 are connected to the first to fourth terminal portions 501-504 by soldering or welding, respectively.

[0022] The protruding piece 500 has fitting holes 500a, 500b into which a pair of protrusions 245a, 245b provided on the base portion 245 of the cable support portion 24 fits. The fitting holes 500a, 500b penetrate the protruding piece 500 in the thickness direction. The protruding piece 500 is fixed to the cable support portion 24 by fitting the pair of protrusions 245a, 245b into the fitting holes 500a, 500b.

[0023] The flexible substrate 5 has a multi-layer structure having first to fourth wiring layers 51 to 54, and is arranged to be curved cylindrically so as to surround from the outside the inner cylindrical portion 21 of the support member 2. The flexible substrate 5 has a coverlay film 551, an adhesive layer 561, the first wiring layer 51, a first base film 571, a second wiring layer 52, an adhesive layer 562, a coverlay film 552, a double-sided tape 58, a coverlay film 553, an adhesive layer 563, a third wiring layer 53, a second base film 572, a fourth wiring layer 54, an adhesive layer 564, and a coverlay film 554 laminated thereon in this order from one surface 5a corresponding to the outside of the curve to the other surface 5b corresponding to the inside of the curve.

[0024] The first wiring layer 51 and the second wiring layer 52 are wiring patterns formed by etching copper foil, and are formed on the front surface 571a and the back surface 571b of the first base film 571, respectively. Similarly, the third wiring layer 53 and the fourth wiring layer 54 are wiring patterns formed by etching copper foil, and are formed on the front surface 572a and the back surface 572b of the second base film 572, respectively. The coverlay films 551, 552, 553, and 554 are protective films attached to the first to fourth wiring layers 51 to 54 by adhesive layers 561, 562, 563, and 564. The first and second base films 571 and 572 and the coverlay films 551, 552, 553, and 554 are made of insulating resin such as polyimide. The double-sided tape 58 is, for example, an acrylic tape.

[0025] Fig. 8(a) is a plan view showing the wiring pattern of the first wiring layer 51 formed on the surface 571a of the first base film 571. Fig. 8(b) is a plan view showing the wiring pattern of the second wiring layer 52 as viewed from the surface 571a side of the first base film 571. Fig. 8(c) is a plan view showing the wiring pattern of the third wiring layer 53 formed on the surface 572a of the second base film 572. Fig. 8(d) is a plan view showing the wiring pattern of the fourth wiring layer 54 as viewed from the surface 572a side of the second base film 572.

[0026] In the first wiring layer 51, first to ninth coils 511 to 519 aligned in the longitudinal direction of the strip-shaped portion 50 are formed by a wiring pattern. The first and ninth coils 511, 519 are triangular, and the second to eighth coils 512 to 518 are parallelogram-shaped. Similarly, in the second wiring layer 52, first to ninth coils 521 to 529 aligned in the longitudinal direction of the strip-shaped portion 50 are formed by a wiring pattern. The first and ninth coils 521, 529 are triangular, and the second to eighth coils 522 to 528 are parallelogram-shaped.

[0027] In addition, the third wiring layer 53 has first to ninth coils 531 to 539 arranged in the longitudinal direction of the strip-shaped portion 50 and formed by a wiring pattern. The first and ninth coils 531, 539 are triangular, and the second to eighth coils 532 to 538 are parallelogram-shaped. Similarly, the fourth wiring layer 54 has first to ninth coils 541 to 549 arranged in the longitudinal direction of the strip-shaped portion 50 and formed by a wiring pattern. The first and ninth coils 541, 549 are triangular, and the second to eighth coils 542 to 548 are parallelogram-shaped.

[0028] The first to ninth coils 511-519 of the first wiring layer 51 and the first to ninth coils 541-549 of the fourth wiring layer 54 each have straight line portions 511a-519a, 541a-549a inclined at a predetermined angle (+45°) to one side with respect to the short side direction of the strip-shaped portion 50. The first to ninth coils 521-529 of the second wiring layer 52 and the first to ninth coils 531-539 of the third wiring layer 53 each have straight line portions 521a-529a, 531a-539a inclined at a predetermined angle (-45°) to the other side with respect to the short side direction of the strip-shaped portion 50.

[0029] 9 is a circuit diagram showing a schematic configuration example of an electric circuit including a flexible substrate 5, a cable 7, an oscillator 91, and a voltmeter 92. The first to ninth coils 511 to 519 of the first wiring layer 51 are directly connected to form a first inductive load 510, and the first to ninth coils 521 to 529 of the second wiring layer 52 are directly connected to form a second inductive load 520. The first to ninth coils 531 to 539 of the third wiring layer 53 are directly connected to form a third inductive load 530, and the first to ninth coils 541 to 549 of the fourth wiring layer 54 are directly connected to form a fourth inductive load 540.

[0030] The first inductive load 510 and the third inductive load 530, and the second inductive load 520 and the fourth inductive load 540 are connected in series between the first terminal 501 and the second terminal 502. A connection line 591 connecting the first inductive load 510 and the third inductive load 530 is connected to the third terminal 503, and a connection line 592 connecting the second inductive load 520 and the fourth inductive load 540 is connected to the fourth terminal 504. The oscillator 91 applies an AC voltage between the first terminal 501 and the second terminal 502. The voltmeter 92 measures the voltage between the third terminal 503 and the fourth terminal 504.

[0031] When torque is applied to the rotating shaft 8, the magnetic permeability decreases (or increases) in the +45 degree direction with respect to the axial direction, and increases (or decreases) in the -45 degree direction with respect to the axial direction. Therefore, when torque is applied to the rotating shaft 8 with an AC voltage applied from the oscillator 91, the inductances of the first inductive load 510 and the fourth inductive load 540 decrease (or increase), and the inductances of the second inductive load 520 and the third inductive load 530 increase (or decrease). As a result, the voltage measured by the voltmeter 92 changes, and the torque applied to the rotating shaft 8 can be detected based on this voltage change.

[0032] In addition, in Figures 8(a) to (d), the wiring patterns of the parts that connect the first to ninth coils 511 to 519, 521 to 529, 531 to 539, 541 to 549 of the first to fourth wiring layers 51 to 54 in series, the connection lines 591, 592, and the wiring patterns between these circuit elements and the first to fourth terminal portions 501 to 504 are omitted.

[0033] The flexible substrate 5 is fastened toward the outer peripheral surface 21b of the inner cylindrical portion 21 of the support member 2 by the heat shrink tube 6, which shrinks when heated. In this embodiment, a hot melt adhesive 61 (see FIG. 3) is applied to the inner surface 6a of the heat shrink tube 6. The hot melt adhesive 61 melts due to heat when the heat shrink tube 6 is shrunk, and is interposed between one surface 5a of the flexible substrate 5 and the inner surface 6a of the heat shrink tube 6, bonding the flexible substrate 5 and the heat shrink tube 6. The other surface 5b of the flexible substrate 5 is in close contact with the outer peripheral surface 21b of the inner cylindrical portion 21 without any gaps. The heat shrink tube 6 is made of a resin material such as polyolefin or polyvinyl chloride, and shrinks at, for example, 150° C. or higher.

[0034] The axial width of the heat shrink tube 6 is wider than the lateral width of the band-shaped portion 50 of the flexible substrate 5, and both lateral ends of the band-shaped portion 50 are covered with the heat shrink tube 6. Both axial ends of the heat shrink tube 6 are bonded to the outer peripheral surface 21b of the inner cylindrical portion 21 of the support member 2 by a hot melt adhesive 61. This fixes the position of the flexible substrate 5 relative to the support member 2.

[0035] Next, a manufacturing method of the magnetostrictive torque sensor 1 will be described with reference to Figures 10 to 12. The manufacturing method of the magnetostrictive torque sensor 1 includes an arrangement step of arranging a flexible substrate 5 on the outer periphery of the inner cylindrical portion 21 of the support member 2 and arranging a heat shrink tube 6 on the outer periphery of the flexible substrate 5, a fastening step of heating and shrinking the heat shrink tube 6 to fasten the flexible substrate 5 toward the outer periphery surface 21b of the inner cylindrical portion 21, an assembly step of assembling the cover member 3 and the cable 7 to the support member 2 to which the flexible substrate 5 is fixed by the heat shrink tube 6, and a molding step of molding the sealing member 4.

[0036] 10 is a perspective view showing the support member 2 and the flexible substrate 5 arranged on the outer periphery of the inner cylindrical portion 21 of the support member 2, together with the heat shrink tube 6 having a hot melt adhesive 61 applied to its inner surface 6a. In FIG. 10, the heat shrink tube 6 before shrinking by heating is shown arranged side by side in the axial direction with the inner cylindrical portion 21 of the support member 2. The inner diameter of the heat shrink tube 6 before shrinking is larger than the outer diameter of the flange portion 22 of the support member 2, and the relative movement between the support member 2 and the heat shrink tube 6 in the axial direction allows the heat shrink tube 6 to pass around the outer periphery of the flange portion 22.

[0037] Fig. 11 is a perspective view showing a state where the heat shrink tube 6 before shrinking is arranged around the flexible substrate 5 and the arrangement step is completed. Fig. 12 is a perspective view showing a state where the heat shrink tube 6 is heated and shrunk from the state shown in Fig. 11 and the fastening step is completed in which the flexible substrate 5 is fastened. The method of heating the heat shrink tube 6 is not particularly limited, but the heat shrink tube 6 can be heated, for example, by blowing hot air onto it or irradiating it with infrared rays. The temperature of the heat shrink tube 6 heated in the fastening step is lower than the temperature (e.g., 300°C) of the molten resin in the molding step.

[0038] The cover member 3 has a function of protecting the flexible substrate 5 and the heat-shrinkable tube 6 from the heat of the molten resin in the molding process. The radial thickness of the outer cylindrical portion 31 is a dimension that can prevent the molten resin from flowing into the accommodation space 100 even when it is subjected to the heat and pressure of the molten resin in the molding process, and is, for example, 1.2 mm or more and 2.7 mm or less. If the thickness of the outer cylindrical portion 31 is less than 1.2 mm, there is a risk that the outer cylindrical portion 31 will melt during the molding process and the molten resin will flow into the accommodation space 100, and if the thickness of the outer cylindrical portion 31 exceeds 2.7 mm, the magnetostrictive torque sensor 1 will become larger than necessary.

[0039] Upon completion of the tightening process, the flexible substrate 5 is tightened by the heat shrink tube 6 and fixed to the inner cylindrical portion 21 of the support member 2, so that the assembly process and molding process can be performed immediately, even before the hot melt adhesive 61 solidifies.

[0040] (Functions and Effects of the Embodiments) According to the embodiment described above, the following actions and effects can be obtained.

[0041] Since the flexible substrate 5, on which the first to ninth coils 511-519, 521-529, 531-539, 541-549 of the first to fourth wiring layers 51-54 are formed by a wiring pattern, is fastened by the heat shrink tube 6 and fixed to the inner cylindrical portion 21 of the support member 2, the flexible substrate 5 can be fixed more quickly than when the flexible substrate 5 is fixed to the inner cylindrical portion 21 by only an adhesive, for example. This makes it possible to improve productivity.

[0042] Since the flexible substrate 5 is fixed to the inner cylindrical portion 21 of the resin-made supporting member 2, peeling of the flexible substrate 5 due to the difference in thermal expansion coefficient with the supporting member 2 is unlikely to occur. Moreover, since the flexible substrate 5 is fastened by the heat shrink tube 6 and fixed to the inner cylindrical portion 21 of the supporting member 2, the flexible substrate 5 is unlikely to peel off from the inner cylindrical portion 21 even due to this fastening.

[0043] Since both ends in the short direction of the band-shaped portion 50 of the flexible substrate 5 are covered with the heat shrink tube 6, the flexible substrate 5 can be kept airtight and moisture absorption by the flexible substrate 5 can be suppressed. Furthermore, since the hot melt adhesive 61 is applied to the inside of the heat shrink tube 6, the flexible substrate 5 can be kept airtight more reliably and the flexible substrate 5 can be prevented from shifting out of position within the accommodation space 100.

[0044] The flexible substrate 5 has a protruding piece 500 disposed outside the heat shrink tube 6, and the first to fourth terminal portions 501 to 504 are provided on this protruding piece 500, so that it is easy to connect to the first to fourth electric wires 71 to 74 of the cable 7. Furthermore, the cable support portion 24 of the support member 2 is provided with protrusions 245a, 245b for fixing the protruding piece 500, so that it is even easier to connect to the first to fourth electric wires 71 to 74.

[0045] By combining the cover member 3 with the support member 2, the molten resin does not come into contact with the flexible substrate 5 and the heat shrink tube 6 during the molding process, so that damage to the flexible substrate 5 and the heat shrink tube 6 due to heat can be prevented.

[0046] In addition, it is desirable that the heat shrink tube 6 is transparent or semi-transparent. If the heat shrink tube 6 is transparent or semi-transparent, the position and posture of the flexible board 5 can be visually confirmed from the outside of the heat shrink tube 6, making it possible to detect defective products.

[0047] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0048] [1] A magnetostrictive torque sensor (1) that is attached around a rotating shaft (8) having a magnetostrictive effect and detects torque applied to the rotating shaft (8), comprising: a support member (2) having a tubular portion (inner cylindrical portion 21) through which the rotating shaft (8) is inserted; a flexible substrate (5) that is arranged on the outer periphery of the tubular portion (21) and on which a plurality of coils (511-519, 521-529, 531-539, 541-549) are formed by a wiring pattern; and a fastening member (heat shrink tube 6) that fastens the flexible substrate (5) toward the outer circumferential surface (21b) of the tubular portion (21).

[0049] [2] The magnetostrictive torque sensor (1) according to the above [1], wherein the fastening member (6) is a cylindrical heat-shrinkable tube (6) that shrinks when heated.

[0050] [3] The magnetostrictive torque sensor (1) described in [1] or [2] above, wherein the flexible substrate (5) has a band-shaped portion (50) in which the plurality of coils (511-519, 521-529, 531-539, 541-549) are arranged in the longitudinal direction, and both ends of the band-shaped portion (50) in the lateral direction are covered by the fastening member (6).

[0051] [4] The magnetostrictive torque sensor (1) according to the above [3], wherein a hot melt adhesive (61) is applied to the inner surface (6a) of the fastening member (6).

[0052] [5] The magnetostrictive torque sensor (1) according to the above item [3] or [4], further comprising a cable (7) having a plurality of electric wires (71-74) connected to the plurality of terminal portions (501-504), the flexible substrate (5) having a protrusion portion (500) extending in a short direction from the strip portion (50) and arranged outside the fastening member (6), the protrusion portion (500) having a plurality of terminal portions (501-504).

[0053] [6] The magnetostrictive torque sensor (1) described in [5] above, wherein a cable support portion (24) for supporting the cable (7) is provided on the support member (2) so as to protrude radially outward from the tubular portion (21), and the cable support portion (24) is provided with a fixing portion (protrusions 245a, 245b) for fixing the protruding piece portion (500).

[0054] [7] The magnetostrictive torque sensor (1) described in [1] to [6] above, comprising a cover member (3) that forms an accommodation space (10) for accommodating the flexible substrate (5) between the cover member (3) and the tubular portion (21) of the support member (2), and a sealing member (4) made of molded resin molded to cover at least a portion of each of the support member (2) and the cover member (3), wherein the cover member (3) is configured to prevent the molded resin from coming into contact with the flexible substrate (5) and the fastening member (6).

[0055] [8] A method for manufacturing the magnetostrictive torque sensor (1) described in [2] above, comprising: an arrangement step of arranging the flexible substrate (5) on the outer periphery of the tubular portion (21) of the support member (2) and arranging the heat shrink tube (6) on the outer periphery of the flexible substrate (5); and a fastening step of heating and shrinking the heat shrink tube (6) and fastening the flexible substrate (5) toward the outer periphery surface (21b) of the tubular portion (21).

[0056] (Additional Note) Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the embodiments described above. It should be noted that not all of the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

[0057] The present invention can be modified as appropriate. For example, in the above embodiment, the magnetostrictive torque sensor 1 has the cover member 3 and the sealing member 7, but depending on the environment of the site where the magnetostrictive torque sensor is installed, the cover member 3 and the sealing member 7 may not be necessary. In the above embodiment, the fastening member is the heat shrink tube 6, but the present invention is not limited to this. As long as it is a member capable of fastening the flexible board 5, for example, a cylindrical elastic body may be used as the fastening member, or an adhesive tape having an adhesive layer formed on one side of a base material made of a strip-shaped resin may be used. [Explanation of symbols]

[0058] 1...Magnetostrictive torque sensor 100...Accommodation space 2... Support member 21... Inner cylindrical portion 21b...Outer periphery 24...Cable support portion 3... Cover member 31... Outer cylindrical portion 4...Sealing member 5...Flexible substrate 50...Strip portion 500...Projection portion 501 to 504: first to fourth terminal portions 511~519, 521~529, 531~539, 541~549... Coil 6...Heat shrink tube 61...Hot melt adhesive 7... Cable 71~74... First to fourth electric wires 8…Rotation axis

Claims

1. A magnetostrictive torque sensor that is attached to a periphery of a rotating shaft having a magnetostrictive effect and detects a torque applied to the rotating shaft, A support member having a cylindrical portion through which the rotating shaft is inserted; a flexible substrate disposed on an outer periphery of the cylindrical portion and having a plurality of coils formed by a wiring pattern; a fastening member that fastens the flexible substrate toward an outer circumferential surface of the cylindrical portion; A magnetostrictive torque sensor equipped with a

2. The fastening member is a cylindrical heat shrink tube that shrinks when heated.

2. The magnetostrictive torque sensor according to claim 1.

3. the flexible substrate has a strip-shaped portion on which the plurality of coils are arranged in a longitudinal direction, Both ends of the band-shaped portion in the short direction are covered by the fastening member.

3. The magnetostrictive torque sensor according to claim 1 or 2.

4. A hot melt adhesive is applied to the inner surface of the fastening member.

4. The magnetostrictive torque sensor according to claim 3.

5. the flexible board has a protruding piece extending from the strip-shaped portion in a short side direction and disposed outside the fastening member, and a plurality of terminals are provided on the protruding piece, A cable having a plurality of electric wires respectively connected to the plurality of terminal portions, 5. The magnetostrictive torque sensor according to claim 3.

6. The support member has a cable support portion for supporting the cable, the cable support portion protruding radially outward from the cylindrical portion, The cable support portion is provided with a fixing portion for fixing the protruding piece portion.

6. The magnetostrictive torque sensor according to claim 5.

7. a cover member that forms an accommodation space for accommodating the flexible board between the cover member and the cylindrical portion of the support member, and a sealing member made of a molding resin that is molded so as to cover at least a part of each of the support member and the cover member, The cover member is configured to prevent the molding resin from coming into contact with the flexible substrate and the fastening member.

7. The magnetostrictive torque sensor according to claim 1 .

8. A method for manufacturing the magnetostrictive torque sensor according to claim 2, comprising the steps of: a positioning step of positioning the flexible substrate on an outer periphery of the cylindrical portion of the support member and positioning the heat shrink tube on an outer periphery of the flexible substrate; a fastening step of heating and shrinking the heat shrink tube to fasten the flexible substrate toward an outer circumferential surface of the cylindrical portion; A method for manufacturing a magnetostrictive torque sensor having the above structure.

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