Torque Measuring Device

Abstract

To provide a torque measuring device that can accurately regulate a position in a radial direction of a sensor board relative to a magnetostriction effect part of a rotating shaft and can restrain an axial dimension.SOLUTION: A torque measuring device 1 includes: a rotating shaft 2 that has a magnetostriction effect part (middle shaft part 6) in which permeability is changed according to transmitted torque in one axial part; a holder 3 that is annularly composed of a non-magnetic material and is not rotated even in use while being disposed around the magnetostriction effect part; a sensor board 4 that is constituted annularly, has a coil for generating a magnetic field for detecting a change in permeability of the magnetostriction effect part, and is supported axially relative to the holder 3; and a regulation member 5 that is held between the magnetostriction effect part and the holder 3 in multiple places in a circumferential direction in the same axial position as that of the sensor board 4, and regulates a position in a radial direction of the holder 3 relative to the magnetostriction effect part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a torque measuring device capable of measuring torque. [Background technology]

[0002] In recent years, in the field of automobiles, there has been progress in the development of systems that measure the torque transmitted by the rotating shaft that constitutes the powertrain, i.e., the power transmission mechanism, and use the measurement results to control the output of the engine or electric motor, which is the power source, or to control the gear shifting of the transmission.

[0003] Conventionally, a magnetostrictive torque measurement method is known as a method for measuring torque transmitted by a rotating shaft. In the magnetostrictive torque measurement method, a sensor for detecting a change in magnetic permeability of a magnetostrictive effect part is disposed near a magnetostrictive effect part provided in a part of the axial direction of the rotating shaft. When torque is applied to the rotating shaft and elastic torsional deformation occurs in the magnetostrictive effect part, the magnetic permeability of the magnetostrictive effect part changes based on the inverse magnetostrictive effect. As a result, the output signal of the sensor changes in response to the change in magnetic permeability of the magnetostrictive effect part, making it possible to measure the torque transmitted by the rotating shaft.

[0004] For example, JP 2019-52912 A (Patent Document 1) describes a specific structure of a magnetostrictive torque measuring device. The torque measuring device described in JP 2019-52912 A (Patent Document 1) includes a rotating shaft having a magnetostrictive effect part in an axial portion, a radial needle bearing for supporting the rotating shaft rotatably relative to a housing, a holder arranged axially adjacent to an outer ring constituting the radial needle bearing and supported by the outer ring, and a sensor fitted and supported by the holder and arranged around the magnetostrictive effect part. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-52912 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a magnetostrictive torque measuring device, it is very important to accurately regulate the radial position of the sensor with respect to the magnetostrictive effect portion of the rotating shaft in order to ensure the accuracy of torque measurement.

[0007] In this regard, in the torque measuring device described in JP 2019-52912 A, the outer ring constituting the radial needle bearing is precisely regulated in radial position relative to the rotating shaft by a plurality of needles constituting the radial needle bearing. The sensor is supported by such an outer ring via a holder. Therefore, the radial position of the sensor can be precisely regulated relative to the magnetostrictive effect part of the rotating shaft.

[0008] However, the torque measuring device described in JP 2019-52912 A still has room for improvement in terms of reducing the axial dimension. That is, in the torque measuring device described in JP 2019-52912 A, a plurality of needles that regulate the radial position of the sensor with respect to the magnetostrictive effect part of the rotating shaft and the sensor are arranged side by side in the axial direction. For this reason, the axial dimension of the torque measuring device tends to be bulky.

[0009] An object of the present invention is to provide a torque measuring device that can accurately regulate the radial position of a sensor substrate with respect to a magnetostrictive effect portion of a rotating shaft and can reduce the axial dimension. [Means for solving the problem]

[0010] A torque measuring device according to one aspect of the present invention includes a rotating shaft, a holder, a sensor substrate, and a restricting member.

[0011] The rotating shaft has, in an axial portion, a magnetostrictive effect portion whose magnetic permeability changes in response to the torque transmitted.

[0012] The holder is made of a non-magnetic material and has an annular shape, is disposed around the magnetostrictive effect portion, and does not rotate even during use.

[0013] The sensor substrate is cylindrically configured, has a coil that generates a magnetic field for detecting a change in magnetic permeability of the magnetostrictive effect portion, and is supported coaxially with respect to the holder.

[0014] The regulating members are held between the magnetostrictive effect portion and the holder at a plurality of circumferential locations at the same axial position as the sensor board, and regulate the radial position of the holder relative to the magnetostrictive effect portion.

[0015] In one embodiment of the torque measuring device of the present invention, the regulating member is made of a magnetic material and is prevented from moving circumferentially relative to the holder, and the coil and the regulating member are arranged at different circumferential positions from each other.

[0016] In the torque measuring device according to one aspect of the present invention, the regulating member is constituted by a rolling element that is in rolling contact with the outer circumferential surface of the magnetostrictive effect portion.

[0017] A torque measuring device according to one embodiment of the present invention includes a retainer that does not rotate even during use, and the rolling elements are held by the retainer, thereby preventing them from moving circumferentially relative to the holder.

[0018] In the torque measuring device according to one aspect of the present invention, the retainer is fixed to the holder.

[0019] In the torque measuring device according to one aspect of the present invention, the retainer is made of a magnetic material and has a shape that does not overlap with the coil in the radial direction.

[0020] In one aspect of the torque measuring device of the present invention, the holder has holder cutouts at multiple circumferential locations that open radially inward, and the rolling elements are arranged inside the holder cutouts.

[0021] In the torque measuring device according to one aspect of the present invention, the rolling elements are constituted by needles.

[0022] In the torque measuring device according to one aspect of the present invention, the regulating member is configured by a sliding member that is fixed to the holder and that is in sliding contact with the outer circumferential surface of the magnetostrictive effect portion.

[0023] In the torque measuring device according to one aspect of the present invention, the sensor substrate has an inner diameter smaller than a diameter of a circumscribing circle of the restricting member centered on the central axis of the magnetostrictive effect portion, and has a substrate cutout portion that penetrates the sensor substrate in the radial direction at a circumferential location where the restricting member is disposed. The restricting member is disposed inside the substrate cutout portion.

[0024] The torque measuring device according to one aspect of the present invention includes a back yoke disposed around the periphery of the sensor substrate. Effect of the Invention

[0025] According to the torque measuring device of one aspect of the present invention, the radial position of the sensor substrate can be accurately regulated with respect to the magnetostrictive effect portion of the rotating shaft, and the axial dimension can be reduced. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view of a torque measuring device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 3 is a perspective view of the torque measuring device of the first example. [Figure 4] FIG. 4 is a perspective view showing the torque measuring device of the first example with the rotating shaft omitted. [Diagram 5] FIG. 5 is an exploded perspective view showing the torque measuring device of the first example with the rotating shaft omitted. [Figure 6] FIG. 6 is a development view of a sensor board constituting the torque measuring device of the first example. [Figure 7]FIG. 7 is a partial sectional view of a torque measuring device according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view of a torque measuring device according to a third embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view of a torque measuring device according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view taken along line BB of FIG. [Figure 11] FIG. 11 is a cross-sectional view of a torque measuring device according to a fifth embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view taken along line CC of FIG. [Figure 13] FIG. 13 is a development view of a sensor board constituting a torque measuring device of the fifth example. [Figure 14] FIG. 14 is a cross-sectional view of a torque measuring device according to a sixth embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view taken along line DD of FIG. [Figure 16] FIG. 16 is a development view of a sensor board constituting a torque measuring device according to the sixth embodiment. [Figure 17] FIG. 17 is a sectional view of a torque measuring device according to a seventh embodiment of the present invention. [Figure 18] FIG. 18 is a cross-sectional view taken along line E-E of FIG. [Figure 19] FIG. 19 is a development view of a sensor board constituting the torque measuring device of the seventh example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] [First Example of Implementation] A first embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG.

[0028] The torque measuring device 1 of this embodiment is a device for measuring torque transmitted by a rotating shaft 2, and can be incorporated into various types of machinery. Specific examples of machinery incorporating the torque measuring device 1 of this embodiment include machinery constituting the power train of an automobile, such as an automatic transmission (AT), a belt-type continuously variable transmission, a toroidal type continuously variable transmission, an automatic manual transmission (AMT), a dual clutch transmission (DCT), or a transmission that changes speed under vehicle control, or a transfer, a manual transmission (MT), and the like. The drive system of the target vehicle, i.e., FF, FR, MR, RR, 4WD, and the like, is not particularly important. Specific examples of machinery incorporating the torque measuring device 1 of this embodiment further include devices that change the rotation speed of a power shaft with gears, such as reducers and speed increasers that constitute windmills, railway vehicles, steel rolling mills, and the like.

[0029] The torque measuring device 1 of this example includes a rotating shaft 2, a holder 3, a sensor board 4, and a restricting member 5.

[0030] Unless otherwise specified, the axial direction of the torque measuring device 1 is the axial direction of the rotating shaft 2, i.e., the left-right direction in Fig. 1. One axial side of the torque measuring device 1 is the left side in Fig. 1, and the other axial side is the right side in Fig. 1.

[0031] The rotating shaft 2 has a magnetostrictive effect part in an axial portion, the magnetic permeability of which changes according to the torque to be transmitted. In this example, the rotating shaft 2 is a rotating shaft that transmits torque from an engine (E) to a transmission (TM). However, when carrying out the present invention, a rotating shaft constituting various mechanical devices can be used as the rotating shaft 2.

[0032] In this example, as shown in FIG. 1, an intermediate shaft portion 6 constituting an axially intermediate portion of a rotating shaft 2 is made to function as a magnetostrictive effect portion. The intermediate shaft portion 6 is a portion of the rotating shaft 2 around which a coil 11, which will be described later, is disposed. For this reason, in this example, the rotating shaft 2 is made of a magnetic metal. As the magnetic metal constituting the rotating shaft 2, various magnetic steels such as carburized steels such as SCr420 and SCM420 and carbon steels such as S45C, as specified by JIS, can be used. The outer circumferential surface of the intermediate shaft portion 6 is formed of a cylindrical surface.

[0033] When the torque measuring device 1 of this embodiment is in use, the rotating shaft 2 is rotatably supported by a rolling bearing (not shown) relative to a housing (not shown).

[0034] When torque is applied to the rotating shaft 2 and torsional deformation occurs in the intermediate shaft section 6, stress according to the torque, that is, tensile stress in a 45° direction with respect to the axial direction and compressive stress in a -45° direction with respect to the axial direction, acts on the intermediate shaft section 6. As a result, the magnetic permeability of the intermediate shaft section 6 changes in each direction due to the inverse magnetostriction effect.

[0035] The holder 3 is made of a non-magnetic material and has an annular shape, as shown in FIG. 5, and is disposed around the intermediate shaft portion 6 so as not to rotate even during use.

[0036] In this embodiment, the holder 3 is made of a synthetic resin, which is a non-magnetic material. However, the non-magnetic material constituting the holder 3 may be, for example, ceramics.

[0037] In this example, the holder 3 has a cylindrical holder cylindrical portion 7, a first outward flange 8 extending radially outward from one axial end of the holder cylindrical portion 7 over the entire circumference, and a second outward flange 9 extending radially outward from the other axial end of the holder cylindrical portion 7 over the entire circumference. The outer diameter of the first outward flange 8 is larger than the outer diameter of the second outward flange 9. The first outward flange 8 has through holes 10 penetrating in the axial direction at multiple circumferential locations (four locations equally spaced circumferentially in the illustrated example) on the radially outer end.

[0038] The holder 3 is disposed around the intermediate shaft portion 6. During use, the holder 3 is connected and fixed to the housing by screwing bolts (not shown) inserted through each of the through holes 10 into screw holes provided in the housing, thereby preventing the holder 3 from rotating during use.

[0039] The sensor substrate 4 is configured in a cylindrical shape, has a coil 11 (see FIG. 6) that generates a magnetic field for detecting a change in magnetic permeability of the intermediate shaft portion 6, and is supported coaxially with the holder 3.

[0040] In this example, the sensor board 4 is formed by rolling a strip-shaped flexible printed circuit board (FPC) into a cylindrical shape. However, when implementing the present invention, the sensor board may also be formed of a cylindrical rigid board. The coil 11 is formed of printed wiring provided on the sensor board 4. When in use, an AC voltage is applied to the coil 11 to generate a magnetic field around the coil 11 for detecting changes in the magnetic permeability of the intermediate shaft portion 6.

[0041] From the viewpoint of improving the torque detection accuracy, it is preferable that the coil 11 is disposed in the entire circumferential region of the sensor substrate 4. However, in this example, the coil 11 is disposed at a different circumferential position from the restricting member 5 so that the magnetic field generated around the coil 11 is less likely to be affected by the restricting member 5 made of a magnetic material.

[0042] FIG. 6 shows a development of the sensor board 4. In this example, the coil 11 is arranged at a circumferential position different from the regulating member 5 shown by the imaginary line (two-dot chain line) in FIG. 6, that is, at each of the α parts surrounded by the dashed line, one coil or, for example, a plurality of coils arranged in the circumferential direction. Therefore, in this example, the number of coils 11 is an integer multiple of the number of regulating members 5. Note that, in the development of FIG. 6, the regulating member 5 at the left end and the regulating member 5 at the right end represent the same regulating member 5. Note that, when implementing the present invention, if the regulating member is made of a non-magnetic material, the coil can be arranged at the same axial position as the regulating member, for example, it can be arranged in the entire circumferential area of ​​the sensor board.

[0043] 6 does not show the specific shape of the coil 11. When implementing the present invention, the specific shape of the coil 11 may be any of various shapes in which a voltage change occurs in the coil 11 in response to a change in the magnetic permeability of the intermediate shaft portion 6, such as a parallelogram in which one pair of opposite sides are parallel to the circumferential direction and the other pair of opposite sides are inclined at 45° to the circumferential direction.

[0044] In this example, the sensor board 4 is fitted and supported on the axial middle portion of the holder cylindrical portion 7, i.e., a portion of the holder cylindrical portion 7 located between the first outward flange 8 and the second outward flange 9 in the axial direction. This allows the sensor board 4 to be supported coaxially with the holder 3. In this example, the outer circumferential surface of the sensor board 4 has a smaller diameter than the outer circumferential surface of the second outward flange 9. In other words, the outer circumferential surface of the sensor board 4 does not protrude radially outward beyond the outer circumferential surface of the second outward flange 9.

[0045] The torque measuring device 1 of this embodiment includes a back yoke 12 arranged around the sensor substrate 4. The back yoke 12 is a member that serves as a magnetic path for the magnetic flux generated by the coil 11, and is made of a magnetic material such as soft steel, and is generally cylindrical. The back yoke 12 is supported by the holder 3 in a state in which it is arranged around the sensor substrate 4 and coaxially with the sensor substrate 4. To this end, specifically, an end face on one axial side of the back yoke 12 is abutted against a radial middle part of a side surface on the other axial side of the first outward flange 8 of the holder 3, and an inner peripheral surface of an end portion on the other axial side of the back yoke 12 is externally fixed to an outer peripheral surface of the second outward flange 9 of the holder 3 by interference fitting, adhesion, or the like.

[0046] In this example, a gap is provided around the entire circumference between the inner peripheral surface of the back yoke 12 and the outer peripheral surface of the sensor substrate 4. This electrically insulates the back yoke 12 from the sensor substrate 4. However, if the back yoke 12 and the sensor substrate 4 can be electrically insulated by, for example, an insulating layer provided on at least one of the inner peripheral surface of the back yoke 12 and the outer peripheral surface of the sensor substrate 4, the inner peripheral surface of the back yoke 12 and the outer peripheral surface of the sensor substrate 4 can be brought into contact with each other.

[0047] The regulating members 5 are held between the intermediate shaft portion 6 and the holder 3 at a plurality of circumferential points at the same axial positions as the sensor board 4, and regulate the radial position of the holder 3 relative to the intermediate shaft portion 6.

[0048] In this example, the regulating members 5 are disposed at a plurality of locations in the circumferential direction between the inner peripheral surface of the axially intermediate portion of the holder cylindrical portion 7 and the outer peripheral surface of the intermediate shaft portion 6, and are sandwiched between these inner peripheral surface and outer peripheral surface. In this way, the regulating members 5 regulate the radial position of the holder 3 relative to the intermediate shaft portion 6.

[0049] The number of the regulating members 5 is preferably three or more and as few as possible. In this example, the number of the regulating members 5 is four, and they are disposed at equal intervals in the circumferential direction.

[0050] When carrying out the present invention, the restricting member 5 can be made of any material as long as the required properties such as strength and wear resistance can be secured. In this example, the restricting member 5 is made of a magnetic material such as magnetic steel. Accordingly, in this example, the restricting member 5 is prevented from moving in the circumferential direction relative to the holder 3. That is, when the restricting member 5 made of a magnetic material crosses the radially inner side of the coil 11 in the circumferential direction during use, the magnetic field generated around the coil 11 is affected, and the torque detection accuracy is deteriorated. Therefore, in order to prevent such inconvenience from occurring, in this example, the restricting member 5 is prevented from moving in the circumferential direction relative to the holder 3.

[0051] In addition, when implementing the present invention, the restricting member may be made of a non-magnetic material such as synthetic resin, non-magnetic steel, ceramics, etc. In this case, the restricting member does not affect the magnetic field generated around the coil 11. Therefore, in this case, the restricting member 5 may be allowed to move in the circumferential direction relative to the holder 3.

[0052] In this example, the regulating member 5 is configured with a rolling element, specifically a needle (needle roller), which is in rolling contact with the outer circumferential surface of the intermediate shaft portion 6. However, when implementing the present invention, balls may also be used as the rolling element. In this example, the regulating member 5 has a central hole 13 penetrating in the axial direction at its radial center.

[0053] The torque measuring device 1 of this example includes a retainer 14 that does not rotate even during use. In this example, the restricting member 5 is held by the retainer 14, thereby preventing the restricting member 5 from moving in the circumferential direction relative to the holder 3.

[0054] In this example, the retainer 14 is fixed to the holder 3. However, when implementing the invention, the retainer can also be fixed to the housing.

[0055] The retainer 14 may be made of any material as long as the required strength and other characteristics can be ensured. In this example, the retainer 14 is made of a magnetic material such as magnetic steel. Accordingly, in this example, in order to reduce the influence of the magnetic field generated around the coil 11, the retainer 14 has a shape that does not overlap with the coil 11 in the radial direction.

[0056] Specifically, the cage 14 has a cylindrical pillar portion 15, the axial middle portion of which is loosely inserted into each central hole 13 of the regulating member 5, two annular rim portions 16 arranged coaxially with a space in the axial direction and connected to both axial ends of the pillar portion 15, and connection portions 17 extending radially outward from multiple circumferential positions of each of the rim portions 16. In this example, the connection portions 17 are arranged at the same positions as the pillar portions 15 in the circumferential direction. At least one of the two rim portions 16 is connected to the axial end portions of the pillar portions 15 by a method such as adhesion or welding after the pillar portions 15 are inserted into the respective central holes 13 of the regulating member 5.

[0057] In this example, in order to fix the retainer 14 to the holder 3, the radially outer ends of the connection parts 17 are connected to the radially inner ends of both axial ends of the holder cylindrical part 7 by a method such as gluing or embedding. In this state, each of the regulating members 5 is allowed to rotate (spin) freely around the column parts 15, and is prevented from moving in the circumferential direction relative to the holder 3.

[0058] That is, in this example, when the rotating shaft 2 rotates in this state, each of the regulating members 5 rotates about the column portion 15 without moving in the circumferential direction. At this time, the contact between the outer circumferential surface of the regulating member 5 and the outer circumferential surface of the intermediate shaft portion 6 is rolling contact, and the contact between the outer circumferential surface of the regulating member 5 and the inner circumferential surface of the holder cylindrical portion 7 is sliding contact.

[0059] In addition, when retainer 14 is fixed to holder 3, each of pillar portions 15 constituting retainer 14 is disposed at a different circumferential position from coil 11, and thus does not overlap radially with coil 11. In addition, each of rim portions 16 and connection portions 17 constituting retainer 14 is disposed at a different axial position from coil 11, and thus does not overlap radially with coil 11. Therefore, in this example, it is possible to make it difficult for the magnetic field generated around coil 11 to be affected by retainer 14.

[0060] In addition, when implementing the present invention, the retainer structure may be one that includes only a column portion 15 whose axial middle portion is loosely inserted into the central hole 13 of the regulating member 5, and connection portions 17 extending radially outward from both axial ends of the column portion 15.

[0061] When implementing the present invention, the cage can be made of a non-magnetic material such as synthetic resin, non-magnetic steel, ceramics, etc. In this case, the cage does not affect the magnetic field generated around the coil 11. Therefore, in this case, the cage can be shaped so as to overlap the coil 11 in the radial direction.

[0062] In the torque measuring device 1 of this example, when torque is applied to the rotating shaft 2, a torsional deformation occurs in the intermediate shaft portion 6, and the magnetic permeability of the intermediate shaft portion 6 changes in each direction. This changes the magnetic flux passing through the inside of the multiple coils 11 provided on the sensor board 4, which in turn changes the inductance of the coils 11, and therefore the voltage of the coils 11. For this reason, the torque transmitted by the rotating shaft 2 can be measured using the voltages of these coils 11, more specifically, using the differential voltage of a bridge circuit including these coils 11.

[0063] In this example, the radial position of the holder 3 relative to the intermediate shaft 6, i.e., the radial position of the coil 11 of the sensor board 4 relative to the intermediate shaft 6, can be accurately restricted by the restricting member 5 sandwiched between the inner peripheral surface of the axial middle part of the holder cylindrical portion 7 and the outer peripheral surface of the intermediate shaft 6. This makes it easy to ensure the accuracy of torque measurement.

[0064] In this example, a configuration is adopted in which a plurality of regulating members 5 that regulate the radial position of the sensor board 4 relative to the intermediate shaft portion 6 are disposed radially inside the sensor board 4. Therefore, the axial dimension of the torque measuring device 1 can be kept small compared to a configuration in which a plurality of regulating members 5 and the sensor board 4 are disposed side by side in the axial direction.

[0065] In this example, a needle with a small diameter is used as the restricting member 5 disposed radially inside the sensor board 4. This makes it easy to reduce the inner diameter of the sensor board 4, that is, to reduce the gap between the coil 11 and the intermediate shaft portion 6. This also makes it easy to ensure the torque measurement accuracy.

[0066] [Second Example of the Implementation Form] A second embodiment of the present invention will be described with reference to FIG.

[0067] In the torque measuring device 1a of this example, the outer diameter of the second outward flange 9a constituting the holder 3a is made smaller than that of the first example of the embodiment, thereby providing a gap over the entire circumference between the outer circumferential surface of the second outward flange 9a and the inner circumferential surface of the back yoke 12. In this example, the back yoke 12 is fixed to the holder 3a by bonding an end face on one axial side of the back yoke 12 to a radially intermediate portion of a side surface on the other axial side of the first outward flange 8 of the holder 3a. The other configurations and effects are similar to those of the first embodiment.

[0068] [Third Example of the Implementation Form] A third embodiment of the present invention will be described with reference to FIG.

[0069] In the torque measuring device 1b of this example, the holder 3b has a first inward flange 18 extending radially inward over the entire circumference from one axial end of the holder cylindrical portion 7, and a second inward flange 19 extending radially inward over the entire circumference from the other axial end of the holder cylindrical portion 7. The inner peripheral surfaces of the first inward flange 18 and the second inward flange 19 are located radially inward from the central axis of the regulating member 5, and are closely opposed to the outer peripheral surface of the intermediate shaft portion 6.

[0070] The back yoke 12a has a cylindrical yoke cylindrical portion 20 and a yoke ring portion 21 that protrudes radially inward over the entire circumference from one axial end of the yoke cylindrical portion 20. The yoke cylindrical portion 20 is disposed around the sensor board 4a, and the yoke ring portion 21 is disposed at a position adjacent to one axial side of the sensor board 4a. In this example, the back yoke 12a is fixed to the holder 3b by fitting the radially inner end face of the yoke ring portion 21 onto the outer circumferential surface of the holder cylindrical portion 7 by tight fitting, adhesive, or the like.

[0071] In this example, for example, by bridging a fastener (not shown) between the housing (not shown) and the holder 3b, it is possible to prevent the holder 3b from rotating relative to the housing. The other configurations and effects are similar to those of the first embodiment.

[0072] [Fourth Example of the Implementation Form] A fourth embodiment of the present invention will be described with reference to FIGS.

[0073] In the torque measuring device 1c of this example, the holder 3c has, at a plurality of circumferential positions, holder cutouts 22 that open radially inward. The restricting member 5, which is constituted by a needle that is a rolling element, is disposed inside the holder cutouts 22.

[0074] 10, the holder cutout portions 22 are provided at four circumferentially equally spaced locations in the axial middle of the holder cylindrical portion 7a, which are circumferential locations where the restricting members 5 are disposed. In this example, each of the holder cutout portions 22 is configured as a rectangular recess that extends in the axial direction and opens only radially inward.

[0075] The regulating members 5 are disposed one by one on the inside of the holder cutout portion 22. In this state, each of the regulating members 5 is sandwiched between the outer circumferential surface of the intermediate shaft portion 6 and the bottom of the holder cutout portion 22. As a result, the regulating members 5 regulate the radial position of the holder 3c relative to the intermediate shaft portion 6, i.e., the radial position of the coil 11 (see FIG. 6) of the sensor board 4 relative to the intermediate shaft portion 6. In this state, the inner circumferential surface of the holder cylindrical portion 7a, which is not included in the holder cutout portion 22, is located radially inward of the central axis of the regulating member 5 and faces closely the outer circumferential surface of the intermediate shaft portion 6.

[0076] In this example, the retainer 14a that holds the regulating member 5 is composed only of a cylindrical column portion whose axial middle portion is loosely inserted into the central hole 13 of the regulating member 5. In this example, in order to fix the retainer 14a to the holder 3c, both axial ends of the retainer 14a are connected by a method such as gluing or embedding to portions of the holder cylindrical portion 7a that are adjacent to both axial sides of the holder cutout portion 22. In this state, each of the regulating members 5 is allowed to freely rotate (spin) around the retainer 14a, and is prevented from moving in the circumferential direction relative to the holder 3c.

[0077] In this example, the outer peripheral surface of the regulating member 5 does not contact the circumferential side surface of the holder cut-out portion 22. However, when implementing the present invention, it is also possible to omit the retainer 14a and have the outer peripheral surface of the regulating member 5 contact the circumferential side surface of the holder cut-out portion 22, thereby preventing circumferential movement of the regulating member 5 relative to the holder 3c. In any case, by arranging the regulating member 5 inside the holder cut-out portion 22 that opens radially inwardly and is provided on the holder 3c, as in the structure of this example, the outer diameter of the holder 3c can be reduced, and therefore the diameter dimension of the torque measuring device 1c can be made compact. The other configurations and effects are similar to those of the first embodiment.

[0078] [Fifth Example of the Implementation Form] A fifth embodiment of the present invention will be described with reference to FIGS.

[0079] In the torque measuring device 1d of this example, the holder hollow portion 22a provided in the holder cylindrical portion 7b of the holder 3d is configured as a rectangular through hole that extends in the axial direction and opens radially inward and radially outward. In this example, the regulating member 5 arranged inside the holder hollow portion 22a is supported by the retainer 14a with respect to the holder 3d and has its outer circumferential surface in rolling contact with the outer circumferential surface of the intermediate shaft portion 6. As a result, the regulating member 5 regulates the radial position of the holder 3d with respect to the intermediate shaft portion 6, i.e., the radial position of the coil 11 of the sensor board 4a with respect to the intermediate shaft portion 6. In this example, the outer circumferential surface of the regulating member 5 does not contact the holder 3d, but the regulating member 5 is supported by the retainer 14a integrated with the holder 3d, so that the relative positional relationship between the regulating member 5 and the holder 3d is kept constant. This makes it possible to regulate the relative positional relationship between the intermediate shaft portion 6 in contact with the regulating member 5 and the holder 3d, that is, the intermediate shaft portion 6 and the sensor board 4a integrated with the holder 3d, at a constant level.

[0080] In this example, the sensor board 4a has an inner diameter smaller than the diameter of a circumscribing circle of the regulating member 5 centered on the central axis of the intermediate shaft portion 6. Accordingly, the sensor board 4a has board cutouts 23 penetrating radially at four circumferentially equally spaced locations where the regulating members 5 are arranged. The regulating members 5 are arranged inside the board cutouts 23. This prevents interference between the sensor board 4a and the regulating members 5. In this example, the board cutouts 23 are formed by cutouts that open on the side edge of the sensor board 4a on the other axial side. However, when implementing the present invention, the board cutouts may also be formed by through holes penetrating the sensor board in the radial direction.

[0081] In this example, the outer diameter of the first outward flange 8a constituting the holder 3d is set to be the same as the outer diameter of the back yoke 12. In this example, for example, a fastener (not shown) is hung between the housing (not shown) and the holder 3d to prevent the holder 3d from rotating relative to the housing.

[0082] In this example, the outer circumferential surface of the regulating member 5 does not come into sliding contact with the holder 3d, so that heat generation and wear due to the sliding contact can be prevented. Also, the inner diameter of the sensor board 4a is smaller than the diameter of the circumscribed circle of the regulating member 5 centered on the central axis of the intermediate shaft 6, so that the distance between the coil 11 of the sensor board 4a and the intermediate shaft 6 can be made smaller. Therefore, the torque measurement accuracy can be improved accordingly. The other configurations and effects are the same as those of the fourth embodiment.

[0083] [Sixth Example of the Implementation Form] A sixth embodiment of the present invention will be described with reference to FIGS.

[0084] In the torque measuring device 1e of this embodiment, the regulating member 5a is fixed to the holder 3e and is configured of a sliding member (bush) that is in sliding contact with the outer circumferential surface of the intermediate shaft portion 6.

[0085] In this example, the restricting member 5a has a rectangular block-shaped main body 24 and a flange 25 provided around the entire circumference of the radially outer end of the main body 24. In this example, in order to fix the restricting member 5a to the holder 3e, the radially outer portion and the flange 25 of the main body 24 of the restricting member 5a are embedded in the axial middle portion of the holder cylindrical portion 7c constituting the holder 3e.

[0086] In this example, the radially inner surface of the main body 24 of the regulating member 5a is in sliding contact with the outer circumferential surface of the intermediate shaft 6. In this way, the regulating member 5a regulates the radial position of the holder 3e relative to the intermediate shaft 6, i.e., the radial position of the coil 11 of the sensor board 4 relative to the intermediate shaft 6. In this example, since the regulating member 5a is fixed to the holder 3e, the torque measuring device 1e can be easily assembled. The other configurations and effects are similar to those of the first embodiment.

[0087] [Seventh Example of the Implementation Form] A seventh embodiment of the present invention will be described with reference to FIGS.

[0088] Fig. 17 shows a cross-sectional view of the torque measuring device 1f of this example. The upper half of Fig. 17 shows a cross-sectional view at a circumferential position where the restricting member 5b is present, and the lower half of Fig. 17 shows a cross-sectional view at a circumferential position where the restricting member 5b is not present.

[0089] In the torque measuring device 1f of this embodiment, the regulating member 5b made of a sliding member is configured as a rectangular block. The regulating member 5b penetrates the holder cylindrical portion 7d constituting the holder 3f in the radial direction. In other words, the regulating member 5b has a radially intermediate portion embedded in the holder cylindrical portion 7d. Furthermore, the regulating member 5b has a groove 26 extending in the axial direction on both circumferential side surfaces of the radially intermediate portion, and a part of the synthetic resin constituting the holder 3 is inserted into the groove 26. This positions the regulating member 5b in the radial direction with respect to the holder 3f.

[0090] In this example, the sensor board 4a has an inner diameter smaller than the diameter of a circumscribing circle of the regulating member 5b centered on the central axis of the intermediate shaft portion 6. Accordingly, the sensor board 4a has board cutouts 23 that penetrate in the radial direction at four circumferentially equally spaced locations where the regulating members 5b are arranged. The regulating members 5b are arranged inside the board cutouts 23. This prevents interference between the sensor board 4a and the regulating members 5b. In this example, the board cutouts 23 are formed by cutouts that open to the side edge on the other axial side of the sensor board 4a.

[0091] In this example, the inner diameter of the sensor board 4a is smaller than the diameter of the circumscribing circle of the restricting member 5b centered on the central axis of the intermediate shaft 6, so that the distance between the coil 11 of the sensor board 4a and the intermediate shaft 6 can be made smaller. Therefore, the torque measurement accuracy can be improved accordingly. The other configurations and effects are the same as those of the sixth embodiment.

[0092] The structures of the above-described embodiments can be appropriately combined and implemented to the extent that no contradiction occurs. [Explanation of symbols]

[0093] 1, 1a-1f Torque measuring device 2 Rotation Axis 3, 3a~3f Holder 4, 4a Sensor board 5, 5a, 5b Regulating member 6 Intermediate shaft 7, 7a to 7d Holder cylindrical part 8 First Outward Flange 9, 9a Second outward flange 10 through hole 11 Coil 12, 12a Back Yoke 13 Center hole 14, 14a retainer 15 Pillar section 16 Rim section 17 Connection 18 First inward flange 19 Second inward flange 20 Yoke cylindrical part 21 Yoke circular ring 22, 22a Holder cutout 23 Substrate removal section 24 Main body 25 Flange 26 Groove

Claims

1. a rotating shaft having a magnetostrictive effect part in an axial portion thereof, the magnetic permeability of which changes in response to a torque to be transmitted; a holder that is made of a non-magnetic material and has an annular shape, is disposed around the magnetostrictive effect part, and does not rotate even during use; a sensor substrate that is cylindrically formed, has a coil that generates a magnetic field for detecting a change in magnetic permeability of the magnetostrictive effect portion, and is supported coaxially with respect to the holder; a restricting member that is held between the magnetostrictive effect portion and the holder at a plurality of circumferential locations at the same axial position as the sensor substrate, and that restricts a radial position of the holder relative to the magnetostrictive effect portion; The restricting member is made of a magnetic material and is prevented from moving in a circumferential direction relative to the holder. The coil and the restricting member are disposed at different circumferential positions. Torque measuring device.

2. 2. The torque measuring device according to claim 1, wherein the regulating member is constituted by a rolling element that is in rolling contact with an outer circumferential surface of the magnetostrictive effect portion.

3. Equipped with a retainer that does not rotate even during use, The rolling elements are held by the cage and prevented from moving in a circumferential direction relative to the holder.

3. A torque measuring device according to claim 2.

4. The torque measuring device according to claim 3 , wherein the retainer is fixed to the holder.

5. 5. The torque measuring device according to claim 3, wherein the cage is made of a magnetic material and has a shape that does not overlap with the coil in the radial direction.

6. The holder has a plurality of holder cutouts in a circumferential direction, the cutouts opening radially inward, The rolling element is disposed inside the holder cutout portion. A torque measuring device according to any one of claims 2 to 5.

7. 7. The torque measuring device according to claim 2, wherein the rolling elements are constituted by needles.

8. 2. The torque measuring device according to claim 1, wherein the regulating member is configured by a sliding member that is fixed to the holder and that is in sliding contact with an outer circumferential surface of the magnetostrictive effect portion.

9. the sensor substrate has an inner diameter smaller than a diameter of a circumscribing circle of the regulating member centered on the central axis of the magnetostrictive effect portion, and has a substrate cutout portion penetrating in a radial direction at a circumferential location where the regulating member is disposed, The regulating member is disposed inside the board cutout portion. A torque measuring device according to any one of claims 1 to 8.

10. a rotating shaft having a magnetostrictive effect part in an axial portion thereof, the magnetic permeability of which changes in response to a torque to be transmitted; a holder that is made of a non-magnetic material and has an annular shape, is disposed around the magnetostrictive effect part, and does not rotate even during use; a sensor substrate that is cylindrically formed, has a coil that generates a magnetic field for detecting a change in magnetic permeability of the magnetostrictive effect portion, and is supported coaxially with respect to the holder; a restricting member that is held between the magnetostrictive effect portion and the holder at a plurality of circumferential locations at the same axial position as the sensor substrate, and that restricts a radial position of the holder relative to the magnetostrictive effect portion; the sensor substrate has an inner diameter smaller than a diameter of a circumscribing circle of the regulating member centered on the central axis of the magnetostrictive effect portion, and has a substrate cutout portion penetrating in a radial direction at a circumferential location where the regulating member is disposed, The regulating member is disposed inside the board cutout portion. Torque measuring device.

11. The torque measuring device according to any one of claims 1 to 10, further comprising a back yoke arranged around the sensor substrate.

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