Magnetostrictive torque sensor

Abstract

[Problem] To achieve the structure of a magnetostrictive torque sensor that can easily secure mountability to a fixed part. [Solution] A holder 4 has a storage recess part 13 that communicates the inner space with the outer space and opens the other side in an axial direction. A portion of a signal line part 43 of a flexible substrate 6 is stored in the storage recess part 13. A connector 7 is attached to the tip of the signal line part 43. A connector support part 26 is provided to support the connector 7 on a cover 5 that covers an opening part of the storage recess part 13.

Description

Magnetostrictive torque sensor

[0001] The present disclosure relates to a magnetostrictive torque sensor that measures torque applied to a rotating shaft.

[0002] As a sensor for measuring torque applied to a rotating shaft, a magnetostrictive torque sensor that measures torque applied to a rotating shaft by utilizing the inverse magnetostrictive effect that occurs in the rotating shaft when torque is applied to the rotating shaft has been known for some time, as described in JP 2022-074405 A, for example.

[0003] The torque sensor described in JP 2022-074405 A has a flexible substrate on which multiple detection coils are printed, which is arranged around the rotating shaft, and detects the torque applied to the rotating shaft based on changes in the inductance of the detection coils.

[0004] In the torque sensor described in JP 2022-074405 A, a flexible substrate is housed inside a resin housing. Signal lines are connected to the detection coils printed on the flexible substrate. The signal lines are bundled into a single cable inside a rectangular cylindrical guide portion provided in the resin housing so as to protrude radially outward, and are then drawn out to external space through the guide portion. The cable is connected to an external detection circuit.

[0005] In the torque sensor disclosed in JP 2022-074405 A, the detection coil for detecting changes in inductance is configured as a detection coil printed on a flexible substrate. That is, according to the torque sensor disclosed in JP 2022-074405 A, it is not necessary to configure each detection coil by winding an insulated wire around a holder, which reduces manufacturing costs.

[0006] Japanese Patent Application Laid-Open No. 2022-074405

[0007] In the torque sensor described in JP 2022-074405 A, the signal wires connected to the detection coil on the flexible printed circuit board are bundled into a single cable inside a rectangular cylindrical guide portion provided in the resin housing so as to protrude radially outward, and are then drawn out to the external space through the guide portion. Therefore, depending on the shape of the portion where the torque sensor is attached and the direction of the cable connection, the work of routing the cable can become cumbersome, which can increase the number of assembly steps and the assembly costs.

[0008] It is possible to change the shape of the guide part and change the cable extraction direction depending on the shape of the part where the torque sensor is attached and the direction of the cable connection destination, etc. However, in this case, multiple types of molds must be prepared to manufacture multiple resin housings with different guide part shapes, which could increase the manufacturing cost of the torque sensor.

[0009] An object of the present disclosure is to realize a magnetostrictive torque sensor structure that can easily ensure attachment to a fixed portion.

[0010] A magnetostrictive torque sensor according to one aspect of the present disclosure is a sensor that measures torque applied to a rotating shaft having magnetostrictive properties, and includes a holder, a cover, a flexible substrate, and a connector.

[0011] The holder has an inner cylindrical portion arranged around the rotation axis, a side plate portion bent radially outward from one axial end of the inner cylindrical portion, an outer cylindrical portion bent from the radially outer end of the side plate portion toward the other axial side, and an accommodating recess that connects an inner space located radially inside the outer cylindrical portion to an outer space located radially outside the outer cylindrical portion and is open on the other axial side.

[0012] The cover closes an opening on the other axial side of the accommodation recess.

[0013] The flexible substrate has a detection section including a plurality of detection coils and arranged around the inner cylindrical section, and a signal line section including a plurality of signal lines electrically connected to the plurality of detection coils, a portion of which is accommodated inside the accommodating recess.

[0014] The connector is attached to the tip of the signal line portion.

[0015] In particular, in the magnetostrictive torque sensor, the cover has a connector support portion for supporting the connector.

[0016] In the magnetostrictive torque sensor according to one aspect of the present disclosure, the cover may have a closing plate portion that closes the opening on the other axial side of the accommodating recess, and a support plate portion that includes the connector support portion.

[0017] In a magnetostrictive torque sensor according to one aspect of the present disclosure, the connector support portion can be formed by a slit, and the connector can be supported on the cover by engaging a portion of the connector with the slit.

[0018] In a magnetostrictive torque sensor according to one aspect of the present disclosure, the cover may have a convex portion disposed inside the accommodating recess, and one of the accommodating recess and the convex portion may have a convex corner portion that increases the contact surface pressure with the signal line portion when the signal line portion is pulled toward the outer space, and the other of the accommodating recess and the convex portion may have a concave corner portion that faces the convex corner portion.

[0019] The magnetostrictive torque sensor according to one aspect of the present disclosure may further include a magnetic ring disposed around the detection portion.

[0020] In the magnetostrictive torque sensor according to one aspect of the present disclosure, the holder may have a cylindrical holder-side mating surface and a holder-side locking hole, and the magnetic ring may have a ring-side mating surface that mates with the holder-side mating surface and a ring-side locking hole. Furthermore, the magnetostrictive torque sensor may include a positioning member that spans the holder-side locking hole and the ring-side locking hole.

[0021] In the magnetostrictive torque sensor according to one aspect of the present disclosure, the holder-side mating surface and the ring-side mating surface can be mated together without any play in the radial direction. Specifically, the holder-side mating surface and the ring-side mating surface can be mated together using a spigot-fit, which is a clearance fit that does not cause any play in the radial direction.

[0022] In one embodiment of the magnetostrictive torque sensor of the present disclosure, the holder side locking hole can be passed radially through the holder, and the positioning member can be protruded radially from one of the openings on either radial side of the holder side locking hole, which is on the radially opposite side to the magnetic ring.

[0023] The magnetostrictive torque sensor according to an aspect of the present disclosure may include a plurality of combinations of the holder-side locking hole, the ring-side locking hole, and the positioning member, or may include a single combination of the holder-side locking hole, the ring-side locking hole, and the positioning member.

[0024] In the magnetostrictive torque sensor according to one aspect of the present disclosure, the positioning member may be a spring pin, or may be a columnar or cylindrical pin, a screw, or the like.

[0025] In a magnetostrictive torque sensor according to one aspect of the present disclosure, the holder-side fitting surface can be provided on the inner peripheral surface of the outer cylindrical portion, and the ring-side fitting surface can be provided on the outer peripheral surface of the magnetic ring.

[0026] When implementing the magnetostrictive torque sensor of the present disclosure, the above-described aspects can be implemented in any suitable combination as long as no contradiction occurs.

[0027] According to the magnetostrictive torque sensor of one aspect of the present disclosure, it is possible to easily ensure attachment to the fixed portion.

[0028] FIG. 1 is a perspective view showing a magnetostrictive torque sensor according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing the magnetostrictive torque sensor according to this embodiment, viewed from the opposite side of FIG. 1 in the axial direction. FIG. 3 is an exploded perspective view showing the magnetostrictive torque sensor according to this embodiment. FIG. 4 is an exploded perspective view showing the magnetostrictive torque sensor according to this embodiment, viewed from the opposite side of FIG. 3 in the axial direction. FIG. 5 is a cross-sectional view of the magnetostrictive torque sensor according to this embodiment. FIG. 6 is a partially enlarged cross-sectional view showing a detection section of a flexible substrate. FIGS. 7(a) to 7(d) are development views of the first to fourth wiring layers as viewed from the radially outer side. FIG. 8 is a schematic diagram showing a detection circuit including four detection coils. FIG. 9 is a development view of the flexible substrate. FIG. 10(a) is an end view of the magnetostrictive torque sensor of this embodiment, viewed from the lower left side of FIG. 1 in the axial direction, with the support plate, connector, and magnetic ring constituting the cover omitted. FIG. 10(b) is an end view of FIG. 10(a) without the cover. FIG. 11(a) is a partially enlarged view of the holder accommodating section as viewed from the axial direction, and FIG. 11(b) is a partially enlarged perspective view of the peripheral portion of the holder accommodating section, with a partial cutaway. FIG. 12(a) is a perspective view of the closing plate of the cover, and FIG. 12(b) is a view from the opposite side of FIG. 12(a). FIG. 13 is a cross-sectional view showing the magnetostrictive torque sensor of this embodiment attached to a fixed portion. FIGS. 14(a) to 14(c) are partially enlarged cross-sectional views showing three examples of modified shapes of the accommodating recess and the cover protrusion. FIG. 15 is a perspective view showing another example of a connector support configuration. FIG. 16 is a perspective view seen from the opposite side to FIG. 15 in the axial direction.

[0029] An example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 16. FIG.

[0030] The magnetostrictive torque sensor 1 of this example is a sensor that measures torque applied to a rotating shaft 2, and is used while supported and fixed to a fixed part 3 that does not rotate even when in use, such as a housing. The magnetostrictive torque sensor 1 includes a holder 4, a cover 5, a flexible substrate 6, and a connector 7. Furthermore, the magnetostrictive torque sensor 1 of this example includes a magnetic ring 8 and positioning members 9a and 9b.

[0031] In the following description, unless otherwise specified, the axial, radial, and circumferential directions of the magnetostrictive torque sensor 1 refer to the axial, radial, and circumferential directions of the rotating shaft 2. The axial, radial, and circumferential directions of the rotating shaft 2 coincide with the axial, radial, and circumferential directions of the holder 4 and also coincide with the axial, radial, and circumferential directions of the magnetic ring 8. Furthermore, one axial side refers to the right side in Fig. 5, and the other axial side refers to the left side in Fig. 5.

[0032] The holder 4 has an inner cylindrical portion 10 , a side plate portion 11 , an outer cylindrical portion 12 , and an accommodating recess 13 .

[0033] The inner cylindrical portion 10 is disposed around the rotating shaft 2 coaxially with the rotating shaft 2 in a state in which the magnetostrictive torque sensor 1 is supported and fixed to the fixed portion 3 .

[0034] In this example, the inner tubular portion 10 has a cylindrical shape. That is, the inner tubular portion 10 has an inner circumferential surface whose inner diameter does not change along the axial direction, and an outer circumferential surface whose outer diameter does not change along the axial direction.

[0035] The side plate portion 11 is bent radially outward from one axial end of the inner cylindrical portion 10. The radially outer end of the side plate portion 11 is connected to one axial end of the outer cylindrical portion 12. In other words, the side plate portion 11 connects one axial end of the inner cylindrical portion 10 to one axial end of the outer cylindrical portion 12. The outer cylindrical portion 12 is also arranged coaxially with the inner cylindrical portion 10.

[0036] In this example, the side plate portion 11 is bent radially outward from one axial end of the inner tubular portion 10, excluding the portion where the accommodating recess 13 is provided. That is, in this example, the side plate portion 11 has a substantially C-shaped end face when viewed from the axial direction.

[0037] The outer cylindrical portion 12 is bent from the radially outer end of the side plate portion 11 toward the other axial side, except for the portion where the installation recess 13 is provided. In other words, the outer cylindrical portion 12 has an overall cut-out cylindrical shape.

[0038] In this example, the axial length of the outer cylindrical portion 12 is shorter than the axial length of the inner cylindrical portion 10. Therefore, the other axial side portion of the inner cylindrical portion 10 also protrudes toward the other axial side near the other axial end of the outer cylindrical portion 12.

[0039] The accommodating recess 13 communicates between an inner space located radially inside the outer cylindrical portion 12 and an outer space located radially outside the outer cylindrical portion 12, and is open on the other axial side.

[0040] The holder 4 of this example includes a bottom plate portion 14 and two side wall portions 15 a and 15 b each of which constitutes the accommodation recess 13 .

[0041] The bottom plate 14 is configured in a generally rectangular flat plate shape. One axial side of the bottom plate 14 is flush with one axial side of the side plate 11, and the other axial side of the bottom plate 14 is flush with the other axial side of the side plate 11.

[0042] The side wall portions 15a, 15b protrude from both circumferential portions of the side surface of the bottom plate portion 14 on the other axial side toward the other axial side.

[0043] As shown in Figures 10(b) to 11(b), the accommodating recess 13 is formed by a portion surrounded on three sides by the other axial side surface of the bottom plate portion 14 and the opposing opposing surfaces 16a, 16b of the side wall portions 15a, 15b.

[0044] Of the two side wall portions 15a, 15b, the opposing surface 16a of one side wall portion 15a is configured by connecting a holder-side first guide surface 17 on the radially inner side to a holder-side second guide surface 18 on the radially outer side by a holder-side inclined guide surface 19. The holder-side second guide surface 18 is positioned offset toward the other side wall portion 15b relative to the holder-side first guide surface 17. The holder-side first guide surface 17 and the holder-side second guide surface 18 are positioned approximately parallel to each other. The holder-side inclined guide surface 19 is inclined in a direction approaching the other side wall portion 15b as it extends radially outward.

[0045] The opposing surface 16b of the other side wall portion 15b is configured by connecting a radially inner holder-side first flat surface 20 and a radially outer holder-side second flat surface 21 by a radially inward-facing stepped surface 22. The holder-side second flat surface 21 is disposed offset toward the one side wall portion 15a from the holder-side first flat surface 20. The holder-side first flat surface 20 and the holder-side second flat surface 21 are disposed approximately parallel to each other.

[0046] Each of the side walls 15a, 15b has a flat seat surface 23a, 23b on the other axial side thereof, the seat surface 23a, 23b being perpendicular to the central axis of the holder 4. The seat surfaces 23a, 23b of the side walls 15a, 15b are offset in the axial direction from the remaining portions.

[0047] The holder 4 further has a holder-side fitting surface 24 having a cylindrical surface shape, and a holder-side locking hole 25 .

[0048] In this example, the holder-side fitting surface 24 is provided on the inner circumferential surface of the outer tubular portion 12. Specifically, the holder-side fitting surface 24 is provided on the entire inner circumferential surface of the outer tubular portion 12 and is configured as a single cylindrical surface whose inner diameter does not change in the axial direction.

[0049] The holder-side locking holes 25 are provided so as to penetrate radially through one or more locations in the circumferential direction of the outer tubular portion 12. In this example, the holder-side locking holes 25 are provided at five locations equally spaced apart in the circumferential direction in a portion of the outer tubular portion 12 that is circumferentially offset from the portion where the accommodating recess 13 is provided.

[0050] The holder 4 is made of synthetic resin, which is a non-magnetic and non-conductive (insulating) material. Specifically, the holder 4 is made of a thermoplastic resin such as epoxy resin, polyphenylene sulfide (PPS), PA (polyamide), or PPA (polyphthalamide). In this example, the holder 4 is integrally formed by injection molding of the synthetic resin. However, when implementing the magnetostrictive torque sensor of the present disclosure, the holder can also be formed by combining multiple parts.

[0051] The cover 5 closes the opening on the other axial side of the accommodating recess 13. The cover 5 also has a connector support portion 26 for supporting the connector 7.

[0052] The cover 5 has a support plate portion 27 including a connector support portion 26 and a closing plate portion 28 that closes the opening on the other axial side of the accommodating recess 13 .

[0053] In this example, the support plate 27 is configured in a substantially rectangular plate shape. The support plate 27 has a recess 29 on one axial side, and slits (grooves) 30a, 30b on circumferentially opposing side surfaces of the recess 29. In this example, the connector 7 is supported relative to the cover 5 by engaging the widthwise edge portions of the supported plate portion 79 of the connector 7 with the slits 30a, 30b. That is, in this example, the connector support portion 26 is configured by the slits 30a, 30b.

[0054] The closing plate 28 has a generally rectangular plate shape. In this example, the closing plate 28 is provided so as to extend radially inward from a circumferential middle portion of the radially inner end of the support plate 27.

[0055] The cover 5 further has a protrusion 31 disposed inside the accommodation recess 13 .

[0056] In this example, the protrusion 31 is provided so as to protrude from a circumferentially intermediate portion of one axially side surface of the blocking plate portion 28 toward one axially side.

[0057] As shown in Figures 12(a) and 12(b), of the pair of outer surfaces 32a, 32b facing opposite sides in the circumferential direction of the protrusion 31, the one outer surface 32a facing the opposing surface 16a of one side wall portion 15a has a shape that follows the opposing surface 16a. Specifically, the one outer surface 32a is configured by connecting a cover-side first guide surface 33 on the radially inner side to a cover-side second guide surface 34 on the radially outer side via a cover-side inclined guide surface 35. The cover-side second guide surface 34 is positioned offset from the cover-side first guide surface 33 toward the other outer surface 32b. The cover-side first guide surface 33 and the cover-side second guide surface 34 are positioned approximately parallel to each other. The cover-side inclined guide surface 35 is inclined in a direction that approaches the other outer surface 32b as it extends radially outward.

[0058] The other outer surface 32b has a shape that follows the opposing surface 16b of the other side wall portion 15b. Specifically, the other outer surface 32b is configured by connecting a radially inner cover-side first flat surface 36 and a radially outer cover-side second flat surface 37 via a stepped surface 38 facing radially outward. The cover-side second flat surface 37 is disposed offset from the cover-side first flat surface 36 toward one of the outer surfaces 32a. The cover-side first flat surface 36 and the cover-side second flat surface 37 are disposed substantially parallel to each other.

[0059] In this example, the convex portion 31 has protrusions 39 that protrude from the other outer surface 32b. In this example, the protrusions 39 are provided at two positions on the cover-side first flat surface 36 in the radial direction.

[0060] The cover 5 is supported by the holder 4 by press-fitting the convex portion 31 into the accommodating recess 13. With the convex portion 31 press-fitted into the accommodating recess 13, the protrusion 39 is pressed against the holder-side first flat surface 20 and elastically deformed. Therefore, the force of the protrusion 39 attempting to elastically restore its original shape biases the convex portion 31 in a direction pressing one outer surface 32a against the opposing surface 16a of one side wall portion 15a. Furthermore, with the cover 5 supported by the holder 4, both circumferential sides of the side surface on one axial side of the closing plate portion 28 are brought into contact with the seat surfaces 23a, 23b, thereby closing the opening on the other axial side of the accommodating recess 13.

[0061] The cover 5 is made of synthetic resin, which is a non-magnetic and non-conductive (insulating) material. Specifically, the cover 5 is made of a thermoplastic resin such as epoxy resin, polyphenylene sulfide (PPS), PA (polyamide), or PPA (polyphthalamide). In this example, the cover 5 is integrally formed by injection molding of the synthetic resin.

[0062] The flexible substrate 6 has a detection section 41 having a plurality of detection coils 40a to 40d for detecting the magnetic field of the rotating shaft 2 and arranged around the inner cylindrical section 10 of the holder 4, and a signal line section 43 having a plurality of signal lines 53a to 53d for electrically connecting the detection section 41 to an external device 42, a part of which is accommodated inside the accommodating recess 13.

[0063] 9 , the detection section 41 is configured in a strip-like or rectangular plate-like shape when the flexible substrate 6 is in an unfolded state. In addition, when the flexible substrate 6 is in an unfolded state, the signal line portion 43 has a protruding portion 44 that protrudes in the short-side direction from one long side of the detection section 41, a linear portion 45 that extends in the long-side direction from the protruding portion 44, and a sensor-side contact mounting portion 80 in the shape of a trapezoidal plate provided at the tip of the linear portion 45.

[0064] The films that make up the flexible substrate 6, i.e., the cover film and / or the base film, are obtained by punching a base material using a punching die. Specifically, a plurality of films are punched out at once from one base material.

[0065] In this example, the detection unit 41 has four detection coils 40a to 40d. As shown in Figures 7(a) to 7(d), each of the detection coils 40a to 40d is configured by arranging a plurality of coil pieces 46a to 46d, 47a to 47d in the circumferential direction (the long side direction of the detection unit 41 when the flexible substrate 6 is in the unfolded state).

[0066] Specifically, the first detection coil 40a is constructed by connecting in series a plurality of coil pieces 46a, 47a arranged in the circumferential direction, the second detection coil 40b is constructed by connecting in series a plurality of coil pieces 46b, 47b arranged in the circumferential direction, the third detection coil 40c is constructed by connecting in series a plurality of coil pieces 46c, 47c arranged in the circumferential direction, and the fourth detection coil 40d is constructed by connecting in series a plurality of coil pieces 46d, 47d arranged in the circumferential direction.

[0067] Of the coil pieces 46a to 46d and 47a to 47d, the coil pieces 46a to 46d located at both ends in the circumferential direction are configured by arranging the wiring pattern so as to be wound in an approximately triangular shape when viewed from the radial direction, and the remaining coil pieces 47a to 47d are configured by arranging the wiring pattern so as to be wound in an approximately parallelogram shape when viewed from the radial direction.

[0068] The coil pieces 46a and 47a constituting the first detection coil 40a and the coil pieces 46c and 47c constituting the third detection coil 40c have straight line portions inclined at a predetermined angle (for example, +45 degrees) in a predetermined direction with respect to the axial direction of the rotation shaft 2 (the direction of the short side of the detection unit 41 when the flexible substrate 6 is in the unfolded state). The coil pieces 46b and 47b constituting the second detection coil 40b and the coil pieces 46d and 47d constituting the fourth detection coil 40d have straight line portions inclined at a predetermined angle (for example, −45 degrees) in a direction opposite to the predetermined direction with respect to the axial direction of the rotation shaft 2.

[0069] The four detection coils 40a to 40d are arranged overlapping one another in the radial direction. Specifically, from the outside in the radial direction, the first detection coil 40a, the second detection coil 40b, the third detection coil 40c, and the fourth detection coil 40d are arranged in this order.

[0070] For this reason, in this example, the flexible substrate 6 has a multi-layer structure having a plurality of wiring layers 48a to 48d.

[0071] 6, the flexible substrate 6 is configured by laminating, in order from the outside in the radial direction, a first coverlay film 49a, a first adhesive layer 50a, a first wiring layer 48a, a first base film 51a, a second wiring layer 48b, a second adhesive layer 50b, a second coverlay film 49b, a double-sided tape 52, a third coverlay film 49c, a third adhesive layer 50c, the third wiring layer 48c, the second base film 51b, a fourth wiring layer 48d, a fourth adhesive layer 50d, and a fourth coverlay film 49d.

[0072] Each of the coverlay films 49a to 49d and the base films 51a and 51b is made of a thin film of an insulating material such as polyimide, polyester, etc. The coverlay films 49a to 49d are protective films for protecting the wiring layers 48a to 48d.

[0073] Each of the wiring layers 48a to 48d is composed of a wiring pattern formed by etching copper foil. The first wiring layer 48a is formed on the radially outer surface of the first base film 51a, and the second wiring layer 48b is formed on the radially inner surface of the first base film 51a. The third wiring layer 48c is formed on the radially outer surface of the second base film 51b, and the fourth wiring layer 48d is formed on the radially inner surface of the second base film 51b.

[0074] Each of the adhesive layers 50a to 50d is made of an adhesive that bonds the coverlay films 49a to 49d, the wiring layers 48a to 48d, and the base films 51a and 51b together. Specifically, each of the adhesive layers 50a to 50d is made of an epoxy resin or acrylic resin adhesive.

[0075] The double-sided tape 52 bonds the second coverlay film 49b and the third coverlay film 49c together.

[0076] In this example, the first detection coil 40a is formed on the first wiring layer 48a, the second detection coil 40b is formed on the second wiring layer 48b, the third detection coil 40c is formed on the third wiring layer 48c, and the fourth detection coil 40d is formed on the fourth wiring layer 48d.

[0077] The detection coils 40a to 40d that constitute the detection unit 41 are electrically connected to the external device 42 by signal lines 53a to 53d and a connector 7 provided on the signal line section 43, a cable connected to the external device 42, and a device-side connector provided at the tip of the cable.

[0078] In this example, the signal line portion 43 has four signal lines 53a to 53d (see FIG. 8).

[0079] Of the four signal lines 53a to 53d, the first signal line 53a connects one end of the first detection coil 40a and one end of the second detection coil 40b in series, and is connected to a first sensor-side contact provided in the connector 7. The first sensor-side contact is engageable with a first device-side contact provided in the device-side connector. The first device-side contact is electrically connected via the cable to one terminal of an oscillator 54 that constitutes the external device 42.

[0080] The second signal line 53b connects one end of the third detection coil 40c and one end of the fourth detection coil 40d in series, and is connected to a second sensor-side contact provided on the connector 7. The second sensor-side contact is engageable with a second device-side contact provided on the device-side connector. The second device-side contact is electrically connected to the other terminal of the oscillator 54 via the cable.

[0081] The third signal line 53c connects the other end of the first detection coil 40a and the other end of the third detection coil 40c in series, and is connected to a third sensor-side contact provided in the connector 7. The third sensor-side contact is engageable with a third apparatus-side contact provided in the apparatus-side connector. The third apparatus-side contact is electrically connected to one terminal of a voltmeter 55 constituting the external device 42 via the cable.

[0082] The fourth signal line 53d connects the other end of the second detection coil 40b and the other end of the fourth detection coil 40d in series, and is connected to a fourth sensor-side contact provided on the connector 7. The fourth sensor-side contact is engageable with a fourth apparatus-side contact provided on the apparatus-side connector. The fourth apparatus-side contact is electrically connected to the other terminal of the voltmeter 55 via the cable.

[0083] Each contact is mounted on a sensor-side contact mounting portion 80. The sensor-side contact mounting portion 80 is housed inside the connector 7. Each contact is configured by a socket, a pin, or the like.

[0084] When the connector 7 is connected to the device-side connector, a bridge circuit including the four detection coils 40a to 40d, the oscillator 54, and the voltmeter 55 is formed.

[0085] The oscillator 54 applies an AC voltage between a contact A connecting one end of the first detection coil 40a and one end of the second detection coil 40b, and a contact B connecting one end of the third detection coil 40c and one end of the fourth detection coil 40d. The voltmeter 55 detects the voltage between a contact C connecting the other end of the first detection coil 40a and the other end of the third detection coil 40c, and a contact D connecting the other end of the second detection coil 40b and the other end of the fourth detection coil 40d.

[0086] When torque T is applied to the rotating shaft 2, stresses σ with opposite signs act on the outer circumferential surface of the rotating shaft 2 in a direction inclined at +45° with respect to the axial direction and in a direction inclined at -45° with respect to the axial direction. Due to the inverse magnetostrictive effect, the magnetic permeability increases in the direction in which tensile stress (+σ) acts, and decreases in the direction in which compressive stress (-σ) acts. In the magnetostrictive torque sensor 1 of this example, the voltage of the bridge circuit, which changes in accordance with the change in magnetic permeability of the rotating shaft 2, is detected by a voltmeter 55, and the direction and magnitude of the torque transmitted by the rotating shaft 2 are determined based on this detected value.

[0087] The signal lines 53 a to 53 d are configured by wiring patterns formed on the wiring layers 48 a to 48 d of the signal line portion 43 .

[0088] The signal line portion 43 is led out to the outside space through the accommodating recess 13 .

[0089] In this example, the connection portion between the protrusion 44 of the signal line portion 43 and the linear portion 45 is bent at approximately a right angle, the base end of the linear portion 45, i.e., the radially inner end, is positioned inside the accommodating recess 13, and the tip portion of the linear portion 45, i.e., the radially outer portion, is pulled out into the outer space.

[0090] According to this example, the connection portion between the protrusion 44 and the linear portion 45 is bent at a substantially right angle, so that the detecting portion 41 can be prevented from floating up from the inner cylindrical portion 10 .

[0091] In other words, when the flexible substrate is bent at the connection between the detection section and the signal line section, the force of the bent section attempting to elastically restore itself may act on the detection section, causing it to lift up from the inner cylindrical section of the holder.

[0092] In contrast, in this example, the connection between the protrusion 44 protruding from one long side of the detection section 41 in the short side direction and the linear section 45 extending from the protrusion 44 in the long side direction is bent at approximately a right angle, so that the force acting on the bent section to elastically restore its original shape can be prevented from acting on the detection section 41 to cause it to lift up from the inner tubular section 10 of the holder 4.

[0093] In this example, the base end of the linear portion 45 extends in a direction substantially perpendicular to the inner tubular portion 10 and the outer tubular portion 12 of the holder 4. Therefore, even if a pulling force is applied to the tip end portion of the linear portion 45, it is possible to prevent a force that would rotate the holder 4 from being applied to the holder 4.

[0094] The base end of the linear portion 45 is sandwiched between the opposing surface 16 a of one side wall portion 15 a and one outer surface 32 a of the protrusion 31 inside the accommodating recess 13 .

[0095] In particular, in this example, when the protrusion 31 is press-fitted into the accommodating recess 13, the elastic restoration force of the protrusion 39 provided on the other outer surface 32b of the protrusion 31 urges the protrusion 31 in a direction pressing the one outer surface 32a against the opposing surface 16a of one side wall 15a. Therefore, the base end of the linear portion 45 is tightly sandwiched between the opposing surface 16a of one side wall 15a and the one outer surface 32a of the protrusion 31. Therefore, even if a pulling force is applied to the tip end portion of the linear portion 45, the force can be prevented from pulling the detection portion 41 radially outward and lifting it up from the inner tubular portion 10.

[0096] In this example, the linear portion 45 is curved in a generally crank-like shape between the opposing surface 16a of one side wall portion 15a and one outer surface 32a of the protrusion 31 and along the opposing surface 16a and the outer surface 32a. Therefore, when a pulling force is applied to the distal end portion of the linear portion 45, the linear portion 45 is pressed against the connection portion of the opposing surface 16a between the holder-side second guide surface 18 and the holder-side inclined guide surface 19, and the connection portion of the outer surface 32a between the cover-side first guide surface 33 and the cover-side inclined guide surface 35, increasing the contact surface pressure with these contact portions. This increase in contact surface pressure increases the frictional resistance acting between the linear portion 45 and the opposing surface 16a and the outer surface 32a. As a result, the detection portion 41 is pulled radially outward, preventing it from lifting off the inner tubular portion 10.

[0097] That is, in this example, the connection portion of the opposing surface 16a between the holder-side second guide surface 18 and the holder-side inclined guide surface 19, and the connection portion of the outer surface 32a between the cover-side first guide surface 33 and the cover-side inclined guide surface 35, respectively, correspond to the convex corner. Also, the connection portion of the outer surface 32a between the cover-side second guide surface 34 and the cover-side inclined guide surface 35, and the connection portion of the opposing surface 16a between the holder-side first guide surface 17 and the holder-side inclined guide surface 19 correspond to the concave corner.

[0098] When implementing the magnetostrictive torque sensor of the present disclosure, the shapes of the opposing surface 16a and the outer surface 32a that sandwich the linear portion 45 can be changed as appropriate as long as it is possible to prevent the detection portion 41 from floating up from the inner cylindrical portion 10.

[0099] 14( a), for example, a small convex portion 56 is provided on the cover-side first guide surface 33 of the outer surface 32a, and a small concave portion 57 is provided on the holder-side first guide surface 17 of the opposing surface 16a. In this modification, when a pulling force is applied to the tip end portion of the linear portion 45, the linear portion 45 is pressed against the small convex portion 56 in addition to the connection portion between the holder-side second guide surface 18 and the holder-side inclined guide surface 19 of the opposing surface 16a and the connection portion between the cover-side first guide surface 33 and the cover-side inclined guide surface 35 of the outer surface 32a. As a result, the contact surface pressure between these contact portions and the small convex portion 56 and the linear portion 45 increases, preventing the detection unit 41 from lifting up from the inner tube portion 10.

[0100] In this modification, the connection between the holder-side second guide surface 18 and the holder-side inclined guide surface 19, the connection between the cover-side first guide surface 33 and the cover-side inclined guide surface 35, and the small convex portion 56 each correspond to a convex corner. Also, the connection between the cover-side second guide surface 34 and the cover-side inclined guide surface 35, the connection between the holder-side first guide surface 17 and the holder-side inclined guide surface 19, and the small concave portion 57 each correspond to a concave corner.

[0101] It is also possible to provide a plurality of small convex portions and small concave portions.Also, it is possible to provide a small convex portion on the opposing surface of one side wall portion and a small concave portion on one outer surface.

[0102] 14(b), the opposing surface 16a of one side wall portion 15a is configured by connecting a radially inner holder-side first guide surface 17 and a radially outer holder-side second guide surface 18 by a radially inner holder-side stepped surface 58. The outer surface 32a is configured by connecting a radially inner cover-side first guide surface 33 and a radially outer cover-side second guide surface 34 by a radially outer cover-side stepped surface 59.

[0103] In this modified example, when a pulling force is applied to the tip end portion of the linear portion 45, the linear portion 45 is pressed against the connection portion of the opposing surface 16a between the holder-side second guide surface 18 and the holder-side step surface 58, and against the connection portion of the outer surface 32a between the cover-side first guide surface 33 and the cover-side step surface 59. As a result, the surface pressure between these contact portions and the linear portion 45 increases, preventing the detection unit 41 from lifting up from the inner cylindrical portion 10.

[0104] In this modification, the connection between the holder-side second guide surface 18 and the holder-side stepped surface 58 and the connection between the cover-side first guide surface 33 and the cover-side stepped surface 59 correspond to convex corners. Also, the connection between the cover-side second guide surface 34 and the cover-side stepped surface 59 and the connection between the holder-side first guide surface 17 and the holder-side stepped surface 58 correspond to concave corners.

[0105] 14(c), the opposing surface 16a of one side wall portion 15a and one outer surface 32a of the protrusion 31 are each configured in a stepped shape. Specifically, the opposing surface 16a has, in order from the inside in the radial direction, a holder-side first guide surface 60, a holder-side first stepped surface 61, a holder-side second guide surface 62, a holder-side second stepped surface 63, and a holder-side third guide surface 64.

[0106] The holder-side second guide surface 62 is offset from the holder-side first guide surface 60 toward the other side wall portion 15b, and the holder-side third guide surface 64 is offset from the holder-side first guide surface 60 toward the other side wall portion 15b. The holder-side first guide surface 60, the holder-side second guide surface 62, and the holder-side third guide surface 64 are arranged substantially parallel to each other. The holder-side first guide surface 60 and the holder-side second guide surface 62 are connected by a holder-side first step surface 61 facing radially inward, and the holder-side second guide surface 62 and the holder-side third guide surface 64 are connected by a holder-side second step surface 63 facing radially inward.

[0107] The outer surface 32a has, in order from the radially inner side, a cover-side first guide surface 65, a cover-side first step surface 66, a cover-side second guide surface 67, a cover-side second step surface 68, and a cover-side third guide surface 69.

[0108] The cover-side second guide surface 67 is offset from the cover-side first guide surface 65 toward one outer surface 32b, and the cover-side third guide surface 69 is offset from the cover-side second guide surface 67 toward the other side wall portion 15b. The cover-side first guide surface 65, the cover-side second guide surface 67, and the cover-side third guide surface 69 are arranged substantially parallel to each other. The cover-side first guide surface 65 and the cover-side second guide surface 67 are connected by a cover-side first step surface 66 facing radially outward, and the cover-side second guide surface 67 and the cover-side third guide surface 69 are connected by a cover-side second step surface 68 facing radially outward.

[0109] In this modified example, when a pulling force is applied to the tip end portion of the linear portion 45, the linear portion 45 is pressed against the connection portion of the opposing surface 16a between the holder-side third guide surface 64 and the holder-side second step surface 63, the connection portion of the holder-side second guide surface 62 and the holder-side first step surface 61, and the connection portion of the outer surface 32a between the cover-side second step surface 68 and the cover-side second guide surface 67, and the connection portion of the cover-side first step surface 66 and the cover-side first guide surface 65. As a result, the contact surface pressure between these contact portions and the linear portion 45 increases, preventing the detection unit 41 from lifting up from the inner cylindrical portion 10.

[0110] In this modified example, the connection portion between the holder-side third guide surface 64 and the holder-side second step surface 63, the connection portion between the holder-side second guide surface 62 and the holder-side first step surface 61, the connection portion between the cover-side second step surface 68 and the cover-side second guide surface 67, and the connection portion between the cover-side first step surface 66 and the cover-side first guide surface 65 each correspond to a convex corner. Also, the connection portion between the holder-side second step surface 63 and the holder-side second guide surface 62, the connection portion between the holder-side first step surface 61 and the holder-side first guide surface 60, the connection portion between the cover-side third guide surface 69 and the cover-side second step surface 68, and the connection portion between the cover-side second guide surface 67 and the cover-side first step surface 66 each correspond to a concave corner.

[0111] The connector 7 is attached to the tip of the signal line portion 43. The connector 7 and the tip of the signal line portion 43 are joined by adhesive, soldering, or the like.

[0112] The connector 7 is supported by the cover 5 .

[0113] In this example, the connector 7 has a connector body 78 and a supported plate portion 79 .

[0114] The connector body 78 has a socket S into which the device-side connector is inserted. Inside the socket S, sensor-side contacts are provided to which the signal lines 53a to 53d are connected.

[0115] In this example, the connector body 78 is configured in a generally rectangular columnar shape. However, when implementing the magnetostrictive torque sensor of the present disclosure, the shape of the connector body is not limited to a generally rectangular columnar shape and can be any shape.

[0116] The supported plate portion 79 is configured in a generally rectangular flat plate shape and is coupled and fixed to one of the four side surfaces of the connector main body 78 in the axial direction.

[0117] In this example, the connector 7 is supported relative to the cover 5 by engaging the widthwise edge portions (circumferential edge portions) of the supported plate portion 79 with the slits 30a, 30b of the support plate portion 27 that constitutes the cover 5. In this example, with the connector 7 supported by the cover 5, the insertion port S faces radially outward.

[0118] In the magnetostrictive torque sensor 1 of this example, by changing the shape of the connector 7 and / or the shape of the cover 5, the orientation of the socket S of the connector 7, i.e., the connection direction of the device-side connector, can be changed.

[0119] Specifically, for example, as shown in Figures 15 and 16, by forming slits on radially opposing sides of a recess provided on one axial side of the support plate portion 27 and engaging the edge portions on both sides of the width of the supported plate portion 79 of the connector 7 with the slits, the connector 7 can be supported relative to the cover 5 so that the insertion port S faces circumferentially.

[0120] In short, with the magnetostrictive torque sensor 1 of this example, the connection direction of the device-side connector can be changed as needed by simply changing the shape of the connector 7 and / or the shape of the cover 5, without changing the shape of the holder 4. Therefore, it is possible to suppress an increase in the manufacturing cost of the magnetostrictive torque sensor 1, while ensuring good attachability of the magnetostrictive torque sensor 1 to the fixed portion 3.

[0121] Furthermore, in the magnetostrictive torque sensor 1 of this embodiment, damage to the flexible substrate 6, particularly the signal line portion 43, can be prevented during the attachment work of the magnetostrictive torque sensor 1 to the fixed portion 3.

[0122] In other words, if the band-shaped signal line portion provided on the flexible substrate is pulled out from the holder that houses the detection portion of the flexible substrate, when attaching the magnetostrictive torque sensor to the fixed part, care must be taken to avoid damaging the signal line portion, which may reduce workability.

[0123] In contrast, in this example, the connector 7 is supported by the cover 5, which prevents damage to the signal line portion 43 when attaching the magnetostrictive torque sensor 1 to the fixed portion 3, making it easier to ensure workability.

[0124] In this example, the connector 7 is supported by the cover 5. In other words, the cover 5, which closes the opening on the other axial side of the accommodating recess 13, also functions as a bracket that supports the connector 7. Therefore, there is no need to provide a separate bracket to support the connector 7, which reduces the number of parts and facilitates cost reduction.

[0125] In addition, when implementing the present disclosure, various structures can be adopted, not limited to the structure of this example, as long as the connector can be supported by the cover. Specifically, for example, the connector can be configured to be supported by a screw or the like against the supported portion of the cover.

[0126] The magnetic ring 8 is also called a back yoke and has the function of preventing the magnetic flux generated by the detection coils 40a to 40d from leaking to the outside. The magnetic ring 8 has a ring-side cylindrical portion 70, a ring-side fitting surface 71, and a ring-side locking hole 72.

[0127] In this example, the magnetic ring 8 is made up of only a ring side cylindrical portion 70, and is configured to have a substantially cylindrical shape as a whole.

[0128] The ring side cylindrical portion 70 is disposed around the detection unit 40. In this example, the ring side cylindrical portion 70 has a small diameter portion 73 on the other axial side, and a large diameter portion 74 at one axial end, the large diameter portion 74 having an outer diameter larger than that of the small diameter portion 73. That is, the ring side cylindrical portion 70 has a stepped cylindrical outer surface in which the outer peripheral surfaces of the small diameter portion 73 and the large diameter portion 74 are connected by a step surface 75 facing the other axial side. In contrast, the inner peripheral surfaces of the small diameter portion 73 and the large diameter portion 74 are located on the same cylindrical surface. Therefore, the radial thickness of the large diameter portion 74 is thicker than the radial thickness of the small diameter portion 73.

[0129] The ring-side fitting surface 71 fits securely with the holder-side fitting surface 24. In this example, the ring-side fitting surface 71 is provided on the outer peripheral surface of the large-diameter portion 74. Specifically, the ring-side fitting surface 71 is provided on the entire outer peripheral surface of the large-diameter portion 74, and is configured as a single cylindrical surface whose outer diameter does not change in the axial direction.

[0130] In this example, the ring-side fitting surface 71 has an outer diameter dimension that is slightly smaller than the inner diameter dimension of the holder-side fitting surface 24. Therefore, when the magnetostrictive torque sensor 1 is assembled, the holder-side fitting surface 24 and the ring-side fitting surface 71 are fitted together by a spigot fit, which is a clearance fit with no play in the radial direction.

[0131] In the magnetostrictive torque sensor 1 of this example, the holder-side mating surface 24 of the holder 4 and the ring-side mating surface 71 of the magnetic ring 8 are mated without any rattle. This ensures good coaxiality between the holder 4 and the magnetic ring 8, and allows a stable magnetic circuit to be formed that passes through the rotating shaft 2, holder 4, and magnetic ring 8.

[0132] However, when implementing the magnetostrictive torque sensor of the present disclosure, the holder-side mating surface and the ring-side mating surface can also be mated by press-fitting (including light press-fitting).

[0133] Furthermore, in this example, the axial length of the holder-side fitting surface 24 and the axial length of the ring-side fitting surface 71 are approximately the same. In other words, the axial length of the outer cylindrical portion 12 and the axial length of the large-diameter portion 74 are approximately the same. Therefore, when the magnetostrictive torque sensor 1 is assembled, the axial position of the stepped surface 75 and the axial position of the other axial end face of the outer cylindrical portion 12 are approximately the same. In other words, the stepped surface 75 and the other axial end face of the outer cylindrical portion 12 are located on approximately the same plane.

[0134] However, the axial length of the outer diameter side cylindrical portion can also be made shorter or longer than the axial length of the large diameter portion.

[0135] The ring-side locking holes 72 are provided so as to open to the outer peripheral surface of the large diameter portion 74, i.e., the ring-side fitting surface 71. In this example, the ring-side locking holes 72 are provided so as to open to five locations on the ring-side fitting surface 71 at equal intervals in the circumferential direction.

[0136] In this example, the ring-side locking hole 72 has a circular opening shape and is configured as a bottomed hole with only the radially outer end open. However, when implementing the magnetostrictive torque sensor of the present disclosure, the opening shape of the ring-side locking hole can be appropriately changed depending on the shape of the positioning member. Also, the ring-side locking hole can be formed so as to radially penetrate the magnetic ring.

[0137] The magnetic ring 8 is integrally formed from a magnetic material. Examples of the magnetic material that can be used for the magnetic ring 8 include iron-based alloys such as mechanical structural alloy steel and stainless steel.

[0138] The positioning members 9a, 9b are fitted over the holder-side locking holes 25 of the holder 4 and the ring-side locking holes 72 of the magnetic ring 8. This reliably prevents relative displacement in the axial and circumferential directions between the holder 4 and the magnetic ring 8 even when the holder 4 and / or the magnetic ring 8 expand or contract due to temperature changes. In other words, the magnetostrictive torque sensor 1 of this example ensures sufficient bonding strength between the holder 4 and the magnetic ring 8, specifically, bonding strength in the axial and circumferential directions.

[0139] The magnetostrictive torque sensor 1 of this example includes five positioning members 9a and 9b.

[0140] Of the five positioning members 9a, 9b, the length of three positioning members 9a is equal to or less than the sum of the radial dimension of the holder-side locking hole 25 and the radial depth of the ring-side locking hole 72. Therefore, the radially outer portion of each positioning member 9a is disposed (inserted) inside the holder-side locking hole 25, and the radially inner portion is disposed (inserted) inside the ring-side locking hole 72. In other words, the radially outer end of the positioning member 9a does not protrude radially outward from the radially outer opening of the holder-side locking hole 25.

[0141] The length of the remaining two positioning members 9b is longer than the sum of the radial dimension of the holder-side locking hole 25 and the radial depth of the ring-side locking hole 72. Therefore, the radial middle portion of each positioning member 9b is disposed (inserted) inside the holder-side locking hole 25, and the radial inner portion is disposed (inserted) inside the ring-side locking hole 72. In other words, the radially outer end of the positioning member 9b protrudes radially outward from the radially outer opening of the holder-side locking hole 25.

[0142] In this example, the positioning members 9a, 9b are each a partially cylindrical spring pin having a linear or wavy slit at one circumferential location. The positioning members 9a, 9b are inserted into the holder-side locking hole 25 and the ring-side locking hole 72 with their outer diameters reduced by elastically narrowing the width of the slit, and then elastically restored to their original shape. As a result, the positioning members 9a, 9b are tightly fitted into at least one of the holder-side locking hole 25 and the ring-side locking hole 72 and are bridged between the holder-side locking hole 25 and the ring-side locking hole 72.

[0143] When implementing the magnetostrictive torque sensor of the present disclosure, the positioning member is not particularly limited as long as it can prevent relative displacement between the holder and the magnetic ring. For example, the positioning member can be configured as a columnar or cylindrical pin. Furthermore, the cross-sectional shape of the positioning member is not limited to a circle, but can also be a non-circular shape such as a partial circle or a polygon. Alternatively, the positioning member can be configured as a screw. In this case, the ring-side locking hole provided in the magnetic ring is a screw hole.

[0144] In this example, the positioning members 9a and 9b are made of a metal material such as an iron alloy or a light alloy, but the material for the positioning members is not particularly limited as long as it can ensure sufficient bonding strength between the holder and the magnetic ring, and synthetic resins and the like can also be used.

[0145] The magnetostrictive torque sensor 1 is supported and fixed to the fixed part 3 in a state where rotation with respect to the fixed part 3 is prevented by fitting the outer cylindrical portion 12 of the holder 4 without rattle into a fixed-side fitting surface 76 provided on the inner peripheral surface of the fixed part 3 and by arranging the radially outer ends of the two positioning members 9b inside locking recesses 77 formed in the fixed-side fitting surface 76. With the magnetostrictive torque sensor 1 supported and fixed to the fixed part 3, the magnetostrictive torque sensor 1 is disposed around the rotating shaft 2. In other words, the magnetostrictive torque sensor 1 is supported and fixed to the fixed part 3 with the rotating shaft 2 inserted inside the inner cylindrical portion 10.

[0146] In this example, with the magnetostrictive torque sensor 1 supported and fixed to the fixed portion 3, a part of the fixed portion 3 abuts against or closely faces the radially outer ends of the positioning members 9 a, 9 b, thereby preventing the positioning members 9 a, 9 b from coming off.

[0147] REFERENCE SIGNS LIST 1 magnetostrictive torque sensor 2 rotating shaft 3 fixed portion 4 holder 5 cover 6 flexible substrate 7 connector 8 magnetic ring 9a, 9b positioning member 10 inner cylindrical portion 11 side plate portion 12 outer cylindrical portion 13 accommodation recess 14 bottom plate portion 15a, 15b side wall portion 16a, 16b opposing surface 17 holder-side first guide surface 18 holder-side second guide surface 19 holder-side inclined guide surface 20 holder-side first flat surface 21 holder-side second flat surface 22 stepped surface 23a, 23b pedestal surface 24 holder-side fitting surface 25 holder-side locking hole 26 connector support portion 27 support plate portion 28 closing plate portion 29 recess 30a, 30b slit 31 protrusion 32a, 32b Outer surface 33 Cover-side first guide surface 34 Cover-side second guide surface 35 Cover-side inclined guide surface 36 Cover-side first flat surface 37 Cover-side second flat surface 38 Step surface 39 Protrusion 40a First detection coil 40b Second detection coil 40c Third detection coil 40d Fourth detection coil 41 Detection unit 42 External device 43 Signal line portion 44 Protrusion 45 Linear portion 46a to 46d Coil pieces 47a to 47d Coil pieces 48a First wiring layer 48b Second wiring layer 48c Third wiring layer 48d Fourth wiring layer 49a First coverlay film 49b Second coverlay film 49c Third coverlay film 49d Fourth coverlay film 50a First adhesive layer 50b Second adhesive layer 50c Third adhesive layer 50d Fourth adhesive layer 51a First base film 51b Second base film 52 Double-sided tape 53a First signal line 53b Second signal line 53c Third signal line 53d Fourth signal line 54 Oscillator 55 Voltmeter 56 Small convex portion 57 Small concave portion 58 Holder-side stepped surface 59 Cover-side stepped surface 60 Holder-side first guide surface 61 Holder-side first stepped surface 62 Holder-side second guide surface 63 Holder-side second stepped surface 64 Holder-side third guide surface 65 Cover-side first guide surface 66 Cover-side first stepped surface 67 Cover-side second guide surface68 Cover-side second stepped surface 69 Cover-side third guide surface 70 Ring-side cylindrical portion 71 Ring-side fitting surface 72 Ring-side locking hole 73 Small diameter portion 74 Large diameter portion 75 Step surface 76 Fixed-side fitting surface 77 Locking recess 78 Connector body 79 Supported plate portion 80 Sensor-side contact mounting portion

Claims

1. A magnetostrictive torque sensor for measuring torque applied to a rotating shaft having magnetostrictive characteristics, comprising: an inner cylindrical portion arranged around the rotating shaft, a side plate portion bent radially outward from one axial end of the inner cylindrical portion, an outer cylindrical portion bent from a radially outer end of the side plate portion towards the other axial side, and a holder having an accommodating recess that connects an inner space located radially inside the outer cylindrical portion to an outer space located radially outside the outer cylindrical portion and is open on the other axial side; a cover that closes the opening on the other axial side of the accommodating recess; a flexible board having a signal line portion including a plurality of detection coils and arranged around the inner cylindrical portion, and a plurality of signal lines electrically connected to the plurality of detection coils, some of which are accommodated inside the accommodating recess; and a connector attached to a tip of the signal line portion, wherein the cover has a connector support portion for supporting the connector.

2. The magnetostrictive torque sensor according to claim 1, wherein the cover has a support plate portion including the connector support portion, and a closing plate portion closing an opening on the other axial side of the accommodating recess.

3. The magnetostrictive torque sensor according to claim 1, wherein the connector support portion is formed by a slit, and the connector is supported on the cover by engaging a part of the connector with the slit.

4. A magnetostrictive torque sensor as described in claim 1, wherein the cover has a convex portion disposed inside the accommodating recess, one of the accommodating recess and the convex portion has a convex corner portion that increases the contact surface pressure with the signal line portion when the signal line portion is pulled toward the outer space, and the other of the accommodating recess and the convex portion has a concave corner portion facing the convex corner portion.

5. The magnetostrictive torque sensor according to claim 1, further comprising a magnetic ring disposed around the detection portion.

6. A magnetostrictive torque sensor as described in claim 5, wherein the holder has a cylindrical holder-side mating surface and a holder-side locking hole, the magnetic ring has a ring-side mating surface that mates with the holder-side mating surface and a ring-side locking hole, and further comprises a positioning member spanning the holder-side locking hole and the ring-side locking hole.

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