JP2006010669A - Torque sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate influence of external noise and to enlarge the output. <P>SOLUTION: An inside yoke 4 made of material of high magnetic permeability between two magnetic sensors 3A and 3B passes the same external noise to two magnetic sensors 3A and 3B, and performs differential detection with the outputs of two magnetic sensors 3A and 3B in response to two poles magnetized in mutually different axial directions. When external noise in the axial direction of a rotating shaft 1 comes, two magnetic sensors 3A and 3B can offset it, and influence of the external noise such as geomagnetism coming from a clearance between the rotating shaft 1 and a shielding member can be eliminated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

 The present invention relates to a torque sensor device, and more particularly to a magnetoelastic torque detection device that measures a torque applied to a rotating shaft in a non-contact manner. This torque sensor device detects the torque of a shaft of a vehicle steering shaft, engine crankshaft, drive shaft, motor or generator input or output shaft, machine tool, transport machine, etc. as a rotating shaft. The present invention relates to a torque sensor device applicable to a device that detects a load state.

 Patent Document: Conventional torque sensor device calibrates to detect essentially “0” when the measured torque is “0”, and changes its direction and magnitude according to the measured torque 1 is a torque sensor device.

 The torque sensor device described in Patent Document 1 is attached to a rotating shaft, torque applied to the rotating shaft is transmitted to the magnetostrictive ring, and the torque applied to the magnetostrictive ring is magnetic in the circumferential direction of the magnetostrictive ring. The directionality is deflected to generate a helical magnetic directionality having both circumferential and axial components. A magnetic field vector sensor is provided at a predetermined position facing the magnetostrictive ring, and is oriented so as to correspond to a magnetic field generated from an axial component of magnetism in the magnetostrictive ring. The output of the magnetic field sensor is proportional to the change in the magnetic direction of the magnetostrictive ring generated by the torque applied to the rotating shaft and transmitted to the magnetostrictive ring.

 With this configuration, the invention disclosed in Patent Document 1 is such that the detected value “0” in the state where the torque is “0” is the temperature, the angular position of the rotational torque member, the rotational speed, the torque member, and its torque amount detection means. Output of the torque sensor device which is substantially unaffected by the radial or longitudinal air gap between them.

Further, no exciting current or coil is required, and the torque sensor device can be manufactured easily and at low cost, and can be introduced into an extremely reliable system. And the necessity of the shield structure for avoiding the detection magnetic field change resulting from a surrounding magnetic field can be minimized or eliminated.
Special table hei 9-511832

 However, in the invention of Patent Document 1, two magnetic sensors shown in Patent Document 1 are arranged at both ends of the yoke, and the arrangement of shield members is an essential requirement. It has been solved by means. That is, even if two magnetic sensors are provided, the influence of the external magnetic field input to these magnetic sensors cannot be ignored, so the shield member is provided.

 All of the magnetic sensors shown in Patent Document 1 are arranged around the rotation shaft, and when the flow of geomagnetism coincides with the direction along the steering shaft of the vehicle, the gap between the rotation shaft and the shield member. There is a high possibility that external noise, such as geomagnetism, that enters from the outside will affect only one of the magnetic sensors. In addition, even if external noise enters the two magnetic sensors at the same time, no countermeasure has been taken to eliminate the influence of the noise from the output of the two magnetic sensors. I could not.

 Therefore, an object of the present invention is to provide a torque sensor device capable of eliminating the influence of external noise and increasing the detection output in order to eliminate these problems.

 The magnetostrictive ring of the torque sensor device according to claim 1 is attached to a rotating shaft made of either a magnetic material or a non-magnetic material, and can be applied by a fixing method such as fitting, press fitting, etc. Any structure may be used as long as both ends of the shaft are integrally fixed by welding or the like and the rotational strain of the rotating shaft is transmitted to the magnetostrictive ring. In addition, the magnetostrictive ring has sections that are magnetized in opposite rotation directions, i.e., two or more poles in the circumferential direction, and magnetized in opposite directions, and by torque applied in the rotation direction, Any magnetic domain change may be used.

 As long as the two magnetic sensors are arranged around the magnetostrictive ring and detect magnetic fields of magnetic poles magnetized in different circumferential directions, a Hall element, Hall IC, semiconductor MR, etc. can be used. Usually, two are used, but the number is not limited to two, and a plurality of three or more may be used.

 The inner yoke disposed between the two magnetic sensors only needs to be able to form a magnetic path with a material having a low magnetic resistance, that is, a high permeability, from the entire circumference or a part of the circumference of the magnetostrictive ring. An annular shape or a semicircular shape is preferable, but when the size is reduced, a rectangular parallelepiped shape, for example, a plate shape may be used.

 The outer yoke arranged outside the two magnetic sensors, like the inner yoke, has a magnetic path made of a material having a low magnetic resistance, that is, a high permeability, from the entire circumference or part of the circumference of the magnetostrictive ring. As long as it can be formed. Preferably, it is an annular shape or a semicircular shape, but it can also be a plate shape when it is downsized.

 The inner yoke of claim 2 forms the magnetic path of two adjacent magnetic sensors, and can be formed by separate yokes, but can also be formed integrally. Further, the magnetic resistance can be reduced by integrating the magnetic sensor and the inner yoke. In any case, any structure may be used as long as the external noise easily causes a magnetic resistance to pass through the two magnetic sensors.

 When the thickness of the inner yoke of claim 3 is increased, the inner yoke crosses the magnetic pole boundary, and although there is a loss in the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring, the cross-sectional area is increased. Since the magnetoresistance is reduced, it is possible to efficiently detect a change in the magnetic field in the axial direction of the rotation axis from the magnetic pole formed on the magnetostrictive ring. In reality, depending on the length of the magnetostrictive ring and the position of the magnetic sensor, The thickness is determined.

 According to the fourth aspect of the present invention, the thicker the inner yoke has a substantially T-shaped cross section, the lower the magnetic resistance. However, since the lower end having a substantially T-shaped cross section is set as the magnetic pole boundary, if the thickness is too thick, a loss in the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring occurs.

 The outer yoke according to claim 5 leads the magnetic field from the end face of the magnetic pole, and the outer yoke can be disposed so that the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring can be used most effectively. The cross-sectional area can be increased accordingly.

 The outer yoke of the sixth aspect has a structure in which an end portion having a substantially L-shaped cross section can be set as an outer end portion of the magnetic pole, and the other end is easily opposed to the magnetic sensor. Since the thickness of the outer yoke at this time may protrude from the end of the magnetostrictive ring, it can be set to an arbitrary thickness.

 Since the outer yoke of claim 7 is formed to have a diameter smaller than the diameter of the end face of the magnetostrictive ring, the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring can be most effectively used. In addition, since the cross-sectional area can be increased as necessary, the magnetic resistance is lowered. The outer yoke having a diameter smaller than the diameter of the end face of the magnetostrictive ring only needs to be able to efficiently detect a change in the magnetic field in the axial direction of the rotary shaft from the magnetic pole formed on the magnetostrictive ring. There is no need to reduce the diameter.

 The inner yoke and the outer yoke of claim 8 can minimize the distance between the outer periphery of the magnetostrictive ring. Here, the arcuate range can be 180 degrees or less, and if necessary, a plurality of arcs of 180 degrees or less can be connected to form a 360 degree magnetic path. And the surface of the opposite side formed in arc shape can be made into arbitrary shapes including arc shape.

 Since the rectangular parallelepiped of the inner yoke and the outer yoke according to the ninth aspect has a lower magnetic resistance than that in the atmosphere, a magnetic field from the magnetostrictive ring can be guided. In this case, it is possible to standardize the two magnetic sensors and the inner and outer yokes. In addition, although the said rectangular parallelepiped can make a magnetic resistance low, so that the cross-sectional area is large, thickness is restrict | limited by the magnetization width | variety and gap | interval of the magnetostriction ring of installation conditions.

 According to the tenth aspect of the present invention, since the magnetic field of external noise such as geomagnetism passes through the shortest linear distance between the inner yoke, the outer yoke, and the two magnetic sensors having low magnetic resistance, the difference between the outputs of the two magnetic sensors. Can be canceled out. Here, if the inner yoke and the outer yoke are set in a plane perpendicular to the axis of the rotary shaft, the straight lines passing through the centers of the two magnetic sensors are in a straight line or substantially parallel to each other, and the rotary shaft It means that it is provided at a position substantially parallel to the axis line.

 The protrusion of claim 11 is to form a low magnetic resistance between the inner and outer yokes and the magnetic sensor, and to give the magnetic sensor a change in the magnetic flux of the magnetostrictive ring without leakage. As long as the magnetic resistance is reduced corresponding to the magnetic field detection portion and the magnetic flux is concentrated, the protruding shape is not questioned.

 The protrusions on the side of the inner yoke and the outer yoke facing the magnetic sensor according to claim 12 are configured so that a magnetic field of external noise such as geomagnetism passes through the two magnetic sensors through a linear position having a small magnetic resistance. It can be canceled out by the difference between the outputs of the two magnetic sensors. Therefore, if the inner yoke and the outer yoke are set in a plane perpendicular to the axis of the rotary shaft, the straight line passing through the centers of the two magnetic sensors is in a straight line or substantially parallel to the center of the protrusion. It means that a straight line passing therethrough is provided at a position substantially parallel to the axis of the rotating shaft.

According to the first aspect of the present invention, even if external noise in the axial direction of the rotating shaft arrives, the output of the two magnetic sensors can be canceled by taking the difference between them by the detection circuit. It is possible to eliminate the influence of external noise such as geomagnetism. Further, since the magnetization change (magnetic field change) of the magnetostriction ring can be guided to the magnetic sensor by the inner yoke and the outer yoke, the magnetization change of the magnetostriction ring can be accurately detected and the detected change amount can be increased.

 According to the second aspect, in addition to the effect of the first aspect, the magnetic resistance can be reduced, and external noise easily passes through the two magnetic sensors.

 In addition to the effect of the first or second aspect, the third aspect of the present invention has a simple structure, and in particular, the magnetic resistance is lowered. Therefore, the magnetic field in the axial direction of the rotating shaft from the magnetic pole formed on the magnetostrictive ring is reduced. Changes can be detected efficiently.

 In addition to the effect of the first or second aspect, the fourth aspect can increase the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring, and can further reduce the magnetoresistance between the two magnetic sensors. The change in the magnetic field in the axial direction of the rotating shaft can be efficiently detected from the magnetic pole formed on the magnetostrictive ring.

 According to a fifth aspect of the present invention, in addition to the effect of any one of the first to fourth aspects, the axial length of the rotation axis of the magnetic pole formed on the magnetostrictive ring can be used most effectively. Since the yoke can be disposed, the cross-sectional area thereof can be increased as required, and the magnetic resistance is reduced, the change in the magnetic field in the axial direction of the rotating shaft can be efficiently detected from the magnetic pole formed on the magnetostrictive ring.

 In addition to the effect of any one of claims 1 to 4, a sixth aspect of the present invention can set an end portion having a substantially L-shaped cross section as an outer end portion of the magnetic pole, and the other end faces the magnetic sensor. The structure is easy to make, the axial length of the rotation axis of the magnetic pole formed on the magnetostriction ring can be increased, and the change of the magnetic field in the axial direction of the rotation axis can be detected efficiently from the magnetic pole formed on the magnetostriction ring. Further, since the thickness of the outer yoke may protrude from the end of the magnetostrictive ring, it can be set to an arbitrary thickness and the magnetic resistance can be arbitrarily reduced.

 In addition to the effect of claim 5 or claim 6, the length of the axial direction of the rotation axis of the magnetic pole formed on the magnetostrictive ring can be used most effectively. Since the cross-sectional area can be increased and the magnetic resistance is reduced, the change in the magnetic field in the axial direction of the rotating shaft from the magnetic pole formed on the magnetostrictive ring can be detected efficiently. In addition, the external noise is efficiently passed through the two magnetic sensors and is not leaked to others, so that the external noise can be easily canceled.

 In the eighth aspect, in addition to the effect of any one of the first to seventh aspects, since the opposing surfaces of the magnetostrictive rings of the inner yoke and the outer yoke are formed in an arc shape, The radius and the curvature can be made substantially on the concentric axis, and the inner yoke and the outer yoke can form a magnetic path that minimizes the distance between the outer periphery of the magnetostrictive ring and the magnetic resistance can be reduced. Further, since the magnetic field obtained from the outer periphery of the magnetostrictive ring is obtained from the range of the length of the arcuate facing surface, a stable output can be obtained. In the case of forming an annular yoke, the assembly performance is improved and the assembly performance is improved, so that the magnetic path can be formed with a minimum distance from the outer periphery of the magnetostrictive ring. Can be reduced.

 In addition to the effects described in any one of claims 1 to 3, 5, 5, 7 and 8, claim 9 can be integrally molded, so that the assembling property is improved. The magnetic sensor, the inner yoke, and the outer yoke can be standardized as one body, and variations in characteristics hardly occur, and it is difficult to be influenced by the outer diameter of the magnetostrictive ring, so that standardization is possible.

 The torque sensor device according to claim 10 has a structure in which a magnetic field of external noise such as geomagnetism easily passes through the two magnetic sensors simultaneously in addition to the effect according to any one of claims 1 to 9. Therefore, it is possible to cancel the difference by the difference between the outputs of the two magnetic sensors.

 In the eleventh aspect, in addition to the effect of any one of the first to tenth aspects, the magnetic resistance passing through the two magnetic sensors is reduced, and the magnetic field of external noise such as geomagnetism is reduced to two. It is possible to increase the probability of passing through the magnetic sensors at the same time, and to cancel the influence of external noise by the difference between the outputs of the two magnetic sensors.

 According to a twelfth aspect, in addition to the effect according to the eleventh aspect, the magnetic resistance passing through the two magnetic sensors is reduced, and the magnetic field of external noise such as geomagnetism is highly likely to pass through the two magnetic sensors at the same time. The difference between the outputs of the two magnetic sensors can be canceled out, and errors due to external noise can be reduced.

 Next, embodiments of the present invention will be described with reference to the drawings.

 In the following embodiments, the same or corresponding components of the common embodiments are denoted by the same symbols or the same reference numerals, and redundant description thereof is omitted.

[Embodiment 1]
FIG. 1 is a perspective view showing the overall configuration of the torque sensor device according to the first embodiment of the present invention, FIG. 2 is a plan view showing the overall configuration of the torque sensor device according to the first embodiment of the present invention, and FIG. FIG. 3 is a detection circuit diagram from two magnetic sensors of the torque sensor device according to the first embodiment. FIG. 4 is an actual measurement characteristic diagram of the torque sensor device according to the first embodiment of the present invention.

 In FIG. 1 and FIG. 2, the rotating shaft 1 made of a magnetic material or a non-magnetic material is a steering shaft in the present embodiment. However, when the present invention is implemented, an engine shaft, a drive shaft, an electric motor, and a power generator It can be used for a shaft that transmits torque, such as an input or output shaft of a machine, a machine tool, or a transport machine. The magnetostrictive ring 2 that generates a magnetization change by a torque applied in the rotation direction is fixed to the rotation shaft 1 and is adjacent to each other and is equally 2 or 3 in the opposite rotation direction, that is, in the circumferential direction. It is magnetized in multiple poles such as 4 etc. This magnetization is normally magnetized so that at least two magnetic poles in the opposite rotation directions are partitioned. When a plurality of magnets are magnetized on three or more odd or even poles, a magnetization change magnetized by two poles in the opposite rotation directions is used. That is, the magnetostrictive ring 2 has magnetized portions 2A and 2B of sections magnetized in opposite directions to each other, two poles in the circumferential direction or two or more poles in the opposite directions, and depending on the torque applied in the rotation direction. The magnetic domains of the magnetized portions 2A and 2B may be changed evenly.

 The magnetostrictive ring 2 can be fitted to the rotating shaft 1 and applied by fixing such as press fitting. In particular, both ends of the magnetostrictive ring 2 are fixed to the rotating shaft 1 by welding or the like, and depending on the applied torque. It is only necessary to transmit the stress in the circumferential direction of the rotating shaft 1.

 The two magnetic sensors 3 </ b> A and 3 </ b> B are disposed around the magnetostrictive ring 2 and are separated from each other in the axial direction, which means the length direction of the central axis OO of the rotating shaft 1. Specifically, the two magnetic sensors 3A and 3B are disposed correspondingly between the magnetized portions 2A and 2B of magnetized magnetic poles that detect magnetic fields in different axial directions. The outputs of these two magnetic sensors 3A and 3B are used in a detection circuit 30 comprising a differential circuit described later. Here, as the two magnetic sensors 3A and 3B, a sensor whose output is changed by a magnetic field such as a Hall element, Hall IC, or semiconductor MR having the same characteristics can be used. The two magnetic sensors 3A and 3B of the present embodiment will be described with two examples. However, for example, two more magnetic sensors 3A and 3B may be arranged at opposing positions around the rotation shaft 1. That is, the rotation shaft 1 may be divided into a plurality of parts, and two pairs of magnetic sensors may be disposed therein, or three or more magnetic sensors may be adjusted by an amplification factor. In any case, the present invention is not limited to the two magnetic sensors 3A and 3B of the present embodiment, and a plurality of magnetic sensors may be used.

 The inner yoke 4 disposed between the two magnetic sensors 3A and 3B at the approximate center in the axial direction of the magnetostrictive ring 2 is made of a material having a high magnetic permeability, thereby reducing the magnetic resistance. Is formed in an annular shape with a substantially square cross section, and is fitted into the rotating shaft 1 with a minute gap, and is disposed around the rotating shaft 1.

 Further, the outer yokes 5 and 6 are disposed on the outermost side of the two magnetic sensors 3A and 3B, and a pair of transparent holes forming a magnetic path between the one magnetic sensor 3A or the magnetic sensor 3B and the inner yoke 4. A magnetic path is formed by lowering the magnetic resistance with a material having a high magnetic susceptibility. The magnetic path is formed in an annular shape, and is fitted into the rotary shaft 1 with a small gap in the same manner as the inner yoke 4. Arranged on both sides of the surrounding inner yoke 4.

 Since two magnetic sensors 3A or 3B are disposed between the inner yoke 4 and the outer yokes 5 and 6, as a result, the inner yoke 4 and the outer yokes 5 and 6 have a uniform width. Even if the magnetic sensor 3A and the magnetic sensor 3B are not provided, the magnetic resistance of the portion where the magnetic sensor 3A and the magnetic sensor 3B are disposed is reduced. Therefore, the inner yoke 4, the magnetized portion 2A of the magnetostrictive ring 2, the outer yoke 5, and the magnetic sensor 3A In addition, a magnetic circuit having a low magnetic resistance is formed using the inner yoke 4, the magnetized portion 2B of the magnetostrictive ring 2 and the outer yoke 6, and the magnetic sensor 3B as a magnetic circuit.

 In FIG. 3, the outputs of the two magnetic sensors 3A and 3B are input to the differential amplifier circuit OP, where the magnetic field components in the same direction of the two magnetic sensors 3A and 3B, that is, different from each other. By detecting the difference between the outputs of the magnetic sensor 3A and the magnetic sensor 3B that detect the magnetic field of the magnetic pole, the external noise is canceled out, and the output is a magnification determined by the input resistance and the feedback resistance f. The detection circuit 30 for inputting the outputs of the two magnetic sensors 3A and 3B to the differential amplifier circuit OP and detecting the difference between them is not limited to this embodiment, and specifically, Other known circuits that detect the difference between the outputs of the two magnetic sensors 3A and 3B that detect magnetic fields of different magnetic poles can be used.

 In the first embodiment, since the two magnetic sensors 3A and 3B having low magnetic resistance are sandwiched between the inner yoke 4 and the outer yokes 5 and 6 made of a material having high magnetic permeability, the resistance of the magnetic circuit Of the magnetostrictive ring 2 and the magnetized part 2B of the magnetostrictive ring 2 that pass the same external noise through the low magnetic sensor 3A and the magnetic sensor 3B and are magnetized in different axial directions. Since the outputs of the two magnetic sensors 3A and 3B are differentially detected corresponding to the two poles, the two magnetic sensors 3A and 3B are detected even when external noise in the axial direction of the rotating shaft 1 arrives. Can cancel each other out, and the influence of external noise such as geomagnetism entering the direction of the rotation axis 1 can be offset by the difference between the outputs of both magnetic sensors 3A and 3B. In addition, since the magnetization change of the magnetostrictive ring 2 can be induced to the magnetic sensors 3A and 3B by the inner yoke 4 and the outer yokes 5 and 6, it is possible to accurately detect the magnetization change of the magnetostrictive ring 2 and increase the amount of change. it can.

 In the first embodiment, as shown in the actual measurement characteristic diagram of FIG. 4, the magnetic field is made uniform by the inner yoke 4 and the outer yokes 5 and 6, and the S / N ratio variation due to the change in the rotation angle is shown in FIG. With respect to 0% disturbance at a specific angle of 0 degree, the disturbance was suppressed to a disturbance of about ± 1% or less at maximum, and substantially uniform characteristics were obtained on the entire circumference of the rotating shaft 1.

[Embodiment 2]
FIG. 5 is an explanatory view showing a planar arrangement structure of the two magnetic sensors, the inner yoke and the outer yoke of Examples (a) to (d) in the torque sensor device according to the second embodiment of the present invention. FIG. 6 is an explanatory view showing a front structure of protrusions of two magnetic sensors, an inner yoke, and an outer yoke of an example in the torque sensor device according to the second embodiment of the present invention.

 In the embodiment of FIG. 5, the magnetic sensor 3A and the magnetic sensor 3B are sandwiched between the inner yoke 4 and the outer yoke 5 or the outer yoke 6, so that the magnetic resistance therebetween is actively reduced. Needless to say, the magnetic resistance is actively reduced, so that the gap between the magnetic sensor 3A, the magnetic sensor 3B and the inner yoke 4, the outer yoke 5 or the outer yoke 6 shown for explanation is in contact. Or, it is in a joined state or a minute interval state.

 That is, in the embodiment of FIG. 5A, the protrusion 5a is formed on the outer yoke 5, and the protrusion 4a is formed on the inner yoke 4, thereby reducing the magnetic resistance between the magnetic sensor 3A. Similarly, a protrusion 6b is formed on the outer yoke 6, and a protrusion 4b is formed on the inner yoke 4, thereby reducing the magnetic resistance between the magnetic sensor 3B. In FIG. 5, for example, a gap is provided between the protrusion 5a of the outer yoke 5, the protrusion 4a of the inner yoke 4, and the magnetic sensor 3A. However, the gap can be eliminated. Similarly, the gap between the protrusion 6b, the protrusion 4b of the inner yoke 4, and the magnetic sensor 3B can be eliminated in the outer yoke 6. Although not described below, the gaps between the protrusions 4a to 4h, 5a to 5d, 6a to 6d of the inner yoke 4 and the outer yokes 5 and 6 and the magnetic sensor 3B are integrally joined to minimize the magnetic resistance. Can be set to

 The protrusions 4a, 4b, 5a and 6a in FIG. 5 (a) have an area where the end face is chamfered. However, when the present invention is carried out, the end face which is not chamfered can be used. Further, the protrusions 4c, 4d, 5b, and 6b in FIG. 5B have a semi-cylindrical shape (end), and have a magnetic flux density increased in a vertical line shape. The protrusions 4e, 4f, 5c, and 6c in FIG. 5C are narrowed down with the end faces chamfered. When narrowing down in this way, the magnetic flux density of the end surfaces of the magnetic sensors 3A and 3B can be narrowed down by the shape of the end portions. When extremely narrowing down, the end surfaces of the protrusions 4g, 4h, 5d, and 6d can be narrowed down linearly as shown in FIG. When narrowing down in this way, the magnetic flux density of the end surfaces of the magnetic sensors 3A and 3B can be sharpened linearly.

 Furthermore, the structure of the protrusions 4g, 4h, 5d, and 6d is not limited to the planar shape shown in FIG. 5, but is narrowed down three-dimensionally as shown in FIG. 6 to form the narrowed end aa or the narrowed end bb. The magnetic flux density of the magnetic field input to the magnetic sensors 3A and 3B can be further increased. Usually, the end faces facing the magnetic sensors 3A and 3B for joining and contacting are narrowed by about 90 to 60% with respect to the outer shape of the magnetic sensors 3A and 3B. Thus, the S / N ratio can be relatively increased by increasing the magnetic flux density.

 Incidentally, using the actual measurement characteristic diagram of FIG. 4 based on the first embodiment, in comparison between the case without a yoke and the case with a yoke, in this embodiment, the variation in the S / N ratio accompanying the change in the rotation angle is ± The disturbance is suppressed to 1% or less, and substantially uniform characteristics can be obtained over the entire circumference of the rotating shaft 1. It is clear that it is reduced to 1/5 or less compared to the case without the yoke.

[Embodiments 3 and 4]
7A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke, and an outer yoke in the torque sensor device according to the third embodiment of the present invention, and FIG. 7B shows a side arrangement structure. It is explanatory drawing. 8A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke, and an outer yoke in the torque sensor device according to the fourth embodiment of the present invention, and FIG. 8B shows a side arrangement structure. It is explanatory drawing.

 In FIG. 7, in the present embodiment, the semicircular inner yokes 4A and 4B, the semicircular outer yokes 5A and 5B, the semicircular outer yokes 5A and 5B are not fitted into the rotary shaft 1 but are assembled. The annular outer yokes 6A and 6B can be retrofitted. Specifically, the two magnetic sensors 3A and 3B, the semi-annular inner yoke 4A, the semi-circular outer yoke 5A, and the semi-circular outer yoke 6A are integrally molded with a resin or the like. The inner yoke 4B, the semi-annular outer yoke 5B, and the semi-circular outer yoke 6B are integrally molded with resin or the like, and are fixed to the rotating shaft 1 to be assembled to the rotating shaft 1. Therefore, this embodiment can improve the assembly workability. These molds may be covered with a shield member in order to further improve the reliability.

 In the fourth embodiment shown in FIG. 8, the semicircular inner yokes 4A and 4B, the semicircular outer yokes 5A and 5B, and the semicircular outer yokes 6A and 6B of the third embodiment are used. The inner yoke and the semicircular outer yoke are eliminated. That is, also in the present embodiment, the semicircular inner yoke 40, the semicircular outer yoke 50, and the semicircular outer yoke 60 are not fitted into the rotary shaft 1 but in a state where the rotary shaft 1 is assembled. Can be retrofitted. Specifically, the two magnetic sensors 3A and 3B, the semi-annular inner yoke 40, the semi-circular outer yoke 50, and the semi-circular outer yoke 60 are integrally molded with resin or the like, and these are arranged on the rotating shaft 1 It is assembled to the rotary shaft 1 by being fixed around. Of course, these molds may be covered with a shield member in order to further improve the reliability. Therefore, this embodiment can improve the assembly workability.

 Here, the inner yoke 4, the outer yoke 5, and the outer yoke 6 of the first to third embodiments having the annular shape are the semicircular inner yoke 40 and the semicircular outer yoke 50 of the fourth embodiment shown in FIG. And the semi-annular outer yoke 60, the semi-annular inner yoke 40, the semi-circular outer yoke 50, and the semi-circular outer yoke 60 obtain a magnetization change of 1/2 that of the magnetostrictive ring 2. The change in the magnetic field of the magnetic sensors 3A and 3B is halved. Therefore, the output change with respect to the magnetic field of the magnetic sensors 3A and 3B is reduced, but the effect on the external noise does not change.

 Needless to say, the shapes of the embodiments shown in FIGS. 5 and 6 can also be used in the third and fourth embodiments.

[Embodiment 5]
FIG. 9A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke and an outer yoke in the torque sensor device according to the fifth embodiment of the present invention, and FIG. 9B is one magnetic sensor. FIG. 9C and FIG. 9C are side views thereof.

 In FIG. 9, for example, between the outer yoke 5 and the sensor outer yoke 8Aa, between the inner yoke 4 and the sensor inner yoke 8Ab, between the outer yoke 6 and the sensor outer yoke 8Bb, and between the inner yoke 4 and the sensor inner yoke. A gap is provided between 8Ba. When the present invention is implemented, the gap can be eliminated and the magnetic resistance can be set to a minimum.

 When practicing the present invention, the magnetic resistance can be lowered from the magnetic sensor 3A, 3B side. That is, the gap between the magnetic sensor 3A and the magnetic sensor 3B and the inner yoke 4 and the outer yoke 5 or the outer yoke 6 sandwiching the magnetic sensor 3A is provided with the sensor inner yoke and the sensor outer yoke on the magnetic sensor 3A and magnetic sensor 3B side. By doing so, the gap can be reduced as much as possible.

 Specifically, a rectangular parallelepiped sensor outer yoke 8Aa and sensor inner yoke 8Ab, and sensor inner yoke 8Ba and sensor outer yoke 8Bb made of a material with high permeability are arranged on both sides of each magnetic sensor 3A and magnetic sensor 3B. Thus, the gap between each magnetic sensor 3A and the inner yoke 4 and the outer yoke 5 is reduced, and similarly, the gap between the magnetic sensor 3B and the inner yoke 4 and the outer yoke 6 is reduced. The resistance can be further reduced. Accordingly, the magnetic resistance of the magnetic circuit of the outer yoke 5, the sensor outer yoke 8Aa, the magnetic sensor 3A, the sensor inner yoke 8Ab, the inner yoke 4, the sensor inner yoke 8Ba, the magnetic sensor 3B, the sensor outer yoke 8Bb, and the outer yoke 6 is minimized. Thus, the external noise in the axial direction of the rotating shaft 1 passes through the magnetic circuit. Accordingly, the external noise passing through the magnetic sensor 3A and the magnetic sensor 3B becomes substantially uniform and can be canceled out.

 The terminals 91 to 93 of the magnetic sensor 3A are power and output terminals, and the magnetic sensor 3B has a similar configuration.

 In the fifth and subsequent embodiments, the gaps between the outer yoke 5 and the sensor outer yoke 8Aa, the sensor inner yoke 8Ab and the inner yoke 4, the inner yoke 4 and the sensor inner yoke 8Ba, and the sensor outer yoke 8Bb and the outer yoke 6 are as follows. Can be eliminated.

 In the fifth embodiment, a rectangular parallelepiped sensor outer yoke 8Aa, a sensor inner yoke 8Ab, a sensor inner yoke 8Ba, and a sensor outer yoke made of a material with high permeability are provided on both sides of each magnetic sensor 3A and magnetic sensor 3B. Although 8Bb is provided, it is desirable to form the rectangular parallelepiped sensor outer yoke 8Aa, sensor inner yoke 8Ab, sensor inner yoke 8Ba, and sensor outer yoke 8Bb as thick as possible.

[Embodiments 6 to 8]
FIG. 10 (a) is a front view of one magnetic sensor in the torque sensor device according to Embodiment 6 of the present invention, FIG. 10 (b) is a side view thereof, and FIG. 11 (a) is Embodiment 7 of the present invention. FIG. 11B is a side view of FIG. 11B, and FIG. 12A is a front view of one magnetic sensor in the torque sensor device according to the eighth embodiment of the present invention. And FIG.12 (b) is the side view. FIG. 13 is a plan view showing a planar structure of two magnetic sensors in the torque sensor device according to the ninth embodiment of the present invention.

 In the above embodiment, the gap between the outer yoke 5 and the sensor outer yoke 8Aa, the sensor inner yoke 8Ab and the inner yoke 4, the inner yoke 4 and the sensor inner yoke 8Ba, and the sensor outer yoke 8Bb and the outer yoke 6 is eliminated. Explained in the direction. However, when practicing the present invention, it is possible to actively separate the two.

 In such a case, it is necessary to form a magnetic path that can easily form a magnetic path for external noise in the magnetic sensor 3A and the magnetic sensor 3B. In the embodiment of FIG. 10, a bent portion 81 is formed by bending each side of the rectangular parallelepiped sensor outer yoke 8Aa and sensor inner yoke 8Ab outward. The magnetic sensor 3B side is similarly formed. Thereby, the magnetic resistance between the opposing magnetic sensor 3A and the magnetic sensor 3B is reduced. As a result, a magnetic path for external noise is easily formed in the magnetic sensor 3A and the magnetic sensor 3B.

 In the embodiment shown in FIG. 11, a convex portion 82 is formed by projecting the center of the rectangular parallelepiped sensor outer yoke 8Aa and sensor inner yoke 8Ab toward the magnetic sensor 3A. The magnetic sensor 3B side is similarly formed. Thus, by increasing the magnetic flux density passing through the opposing magnetic sensors 3A and 3B and reducing the magnetic resistance therebetween, a magnetic path for external noise is easily formed in the magnetic sensors 3A and 3B. Become.

 In the embodiment of FIG. 12, a convex portion (a concave portion viewed from the outside) 82 is formed by projecting the center of the rectangular parallelepiped sensor outer yoke 8Aa and sensor inner yoke 8Ab toward the magnetic sensor 3A, and A convex portion (a concave portion viewed from the outside) 82 protruding to the magnetic sensor 3A side is also formed at the center of the rectangular parallelepiped sensor outer yoke 8Aa and sensor inner yoke 8Ab. The magnetic sensor 3B side is similarly formed. Thus, by increasing the magnetic flux density passing through the opposing magnetic sensors 3A and 3B and reducing the magnetic resistance therebetween, a magnetic path for external noise is easily formed in the magnetic sensors 3A and 3B. is doing.

 Furthermore, according to experiments by the inventors, the following was confirmed. That is, the structure of the sensor outer yoke 8Aa, the sensor inner yoke 8Ab and the magnetic sensor 3B, the sensor inner yoke 8Ba, and the sensor outer yoke 8Bb of the magnetic sensor 3A according to the embodiment shown in FIGS. 5. Even if the outer yoke 6 is omitted, the influence of external noise can be reduced by the detection circuit 30 to such an extent that the application is not affected. Of course, the structure of the sensor outer yoke 8Aa, the sensor inner yoke 8Ab, the sensor inner yoke 8Ba, and the sensor outer yoke 8Bb is not limited to a rectangular parallelepiped shape, but may be a cylindrical shape.

 That is, in each of the embodiments described above, it is basically a problem whether the same external noise is introduced to the two magnetic sensors 3A and 3B. The inner yoke 4, the outer yoke 5, the outer yoke 6 is a requirement to increase the S / N ratio of the two magnetic sensors 3A and 3B by increasing the signal magnetic flux to be extracted. Therefore, depending on the required S / N ratio, the inner yoke 4 , 40, outer yokes 5, 50 and outer yokes 6, 60 can be omitted. As shown in the actual measurement characteristic diagram of FIG. 4, the S / N ratio changes depending on the rotation angle of about 0 to 2.5% in the comparison between the case without the yoke and the case with the yoke.

 In particular, the magnetic sensor 3A, the sensor outer yoke 8Aa, the sensor inner yoke 8Ab, the magnetic sensor 3B, the sensor inner yoke 8Ba, and the sensor outer yoke 8Bb are bonded and then resin-molded. When the is stored, the influence of noise can be further reduced and the S / N ratio can be increased.

 Of course, even when the inner yokes 4, 40, the outer yokes 5, 50, and the outer yokes 6, 60 are used, if they are housed in the magnetic shield case, the influence of noise can be further reduced and the S / N ratio can be increased.

 The torque sensor device of the embodiment of FIG. 10 to FIG. 13 is magnetized with two or more poles in the rotation direction that are adjacent to each other and opposite to each other, in the example, two poles, and generates a magnetization change by torque applied in the rotation direction Corresponding to the magnetostrictive ring 2 attached to the rotating shaft 1 and the magnetized two poles disposed around the magnetostrictive ring 2 and separated in the axial direction of the rotating shaft 1 to detect magnetic fields in different axial directions. Corresponding to the magnetic poles of two or more sections formed in the magnetostrictive ring 2, it passes through two magnetic sensors 3A, 3B and two magnetic sensors 3A, 3B disposed along the axial direction of the rotary shaft 1. A transparent circuit disposed between the detection circuit 30 that detects an output corresponding to a common magnetic field in a single direction as a difference, and the two magnetic sensors 3A and 3B, and in the approximate center in the axial direction of the magnetostrictive ring 2. A yoke made of a material having a high magnetic permeability, that is, the sensor inner yoke 8A The sensor inner yoke 8Ba is disposed between the outer sides of the two magnetic sensors 3A and 3B, and a magnetic path is formed between one of the magnetic sensors 3A and 3B, the sensor inner yoke 8Ab, and the sensor inner yoke 8Ba. A pair of high magnetic permeability yokes, that is, a sensor outer yoke 8Aa on the magnetic sensor 3A side and a sensor outer yoke 8Bb on the magnetic sensor 3B side may be provided.

 As shown in FIG. 13, the sensor inner yokes 8Ab, 8Ba disposed between the two magnetic sensors 3A, 3B of the torque sensor device according to the above embodiment are arranged so that the rotating shafts 1 of the two magnetic sensors 3A, 3B The connecting yoke 80 can be formed so as to be opposed to each other on both inner sides in the axial direction and integrally formed. In this embodiment, the external noise that passes through the two magnetic sensors 3A and 3B must be substantially the same, so that the canceling effect becomes remarkable and the S / N ratio can be increased. In other words, since the external noise has a structure that makes the magnetic resistance easy to pass through the two magnetic sensors 3A and 3B, for example, the two magnetic sensors 3A and 3B may be bonded to the inner yoke 4. means. In any case, any structure may be used as long as external noise easily causes the magnetic resistance to pass through the two magnetic sensors 3A and 3B.

[Embodiment 9]
FIG. 14A is a front explanatory view showing the configurations of the magnetostrictive ring and the yoke in the torque sensor device according to the ninth embodiment of the present invention, and FIG. 14B is an explanatory view showing the right side view thereof.

 FIG. 14 is not fitted to the rotating shaft 1 as in the fourth embodiment of FIG. 8, but is provided with two magnetic sensors 3A, 3B molded with synthetic resin or the like in a state where the rotating shaft 1 is assembled. The semi-annular inner yoke 40, the semi-annular outer yoke 50, and the semi-circular outer yoke 60 can be integrated and retrofitted to improve the assembling workability.

 One surface of the magnetic sensor 3A and the magnetic sensor 3B is disposed on the outside of the semi-annular outer yoke 50 and the semi-circular outer yoke 60 of the ninth embodiment by bonding. Further, the connecting yoke 80 is connected to the other side surfaces of the magnetic sensor 3A and the magnetic sensor 3B, and the center of the connecting yoke 80 is connected to the semi-annular inner yoke 40.

 Therefore, the semi-annular inner yoke 40, the semi-circular outer yoke 50, and the semi-circular outer yoke 60 obtain a change in magnetization of ½ of the magnetostrictive ring 2, and change the magnetic field of the magnetic sensors 3A and 3B. It will be halved. Therefore, in this type of embodiment, a substantially uniform magnetic field can be obtained over the entire circumference of the rotating shaft 1, the output can be increased, and a high S / N ratio can be obtained. Further, the output change with respect to the magnetic field of the magnetic sensors 3A and 3B is reduced, but the effect on the external noise is not changed.

 Moreover, although the output change with respect to the magnetic field of magnetic sensor 3A, 3B decreases, the effect with respect to external noise does not change. In particular, external noise in the axial direction of the rotary shaft 1, that is, in the direction of the central axis OO does not enter the semi-annular outer yoke 50 and the semi-annular outer yoke 60 but directly enters the connecting yoke 80. It is possible to pass through without affecting the magnetic sensors 3A and 3B.

 Even if the magnetic sensor 3A and the magnetic sensor 3B are passed, both can be canceled by the differential amplifier OP.

 One surface of the magnetic sensor 3A and the magnetic sensor 3B is disposed on the outside of the semi-circular outer yoke 50 and the semi-circular outer yoke 60 of the ninth embodiment by bonding, and the magnetic sensor 3A and the magnetic sensor 3B are connected to each other. A connecting yoke 80 is connected to the other surface, and the center of the connecting yoke 80 is connected to the semi-annular inner yoke 40. Therefore, since the magnetic sensor 3A and the magnetic sensor 3B are disposed at a position where the radial magnetic field of the rotary shaft 1 is introduced, the magnetic sensor 3A and the magnetic sensor 3B can cope with the external noise in the radial direction of the rotary shaft 1, and the rotary shaft 1 as external noise. This is an effective configuration when a magnetic field in the axial direction is predicted.

 Conversely, the torque sensor device of the first embodiment of the present invention shown in FIGS. 1 to 3, the second embodiment of the present invention shown in FIGS. 5 and 6, the third embodiment of FIG. 7, and the implementation of FIG. In the fourth embodiment and the fifth embodiment shown in FIG. 9, the magnetic sensor 3A and the magnetic sensor 3B are arranged at positions where the magnetic field in the length direction of the central axis OO of the rotary shaft 1 is introduced. This arrangement can cope with external noise in the axial direction of the shaft 1 and is effective when a magnetic field in the axial direction of the rotary shaft 1 is predicted as external noise.

[Embodiment 10]
FIG. 15 is a perspective view showing the overall configuration of the torque sensor device according to the tenth embodiment of the present invention, and FIG. 16 is a plan view showing the overall configuration of the torque sensor device according to the tenth embodiment of the present invention.

 15 and 16, the common central axis XX of the two magnetic sensors 3 </ b> A and 3 </ b> B is arranged in parallel or substantially parallel to the periphery of the magnetostrictive ring 2, and the central axis OO of the rotary shaft 1. Are disposed apart in the same axial direction. Specifically, it is in the axial direction parallel to the axial direction of the axis of the rotating shaft 1 (central axis OO). Note that the central axes of the two magnetic sensors 3A and 3B do not necessarily need to coincide with the central axis XX, and may be substantially coincident (substantially parallel). Between the two magnetic sensors 3A and 3B, the inner yoke 4 and the outer yokes 5 and 6 disposed approximately at the center in the axial direction of the magnetostrictive ring 2 are the central axes O− of the inner yoke 4 and the outer yokes 5 and 6, respectively. The inner yoke 4 and the outer yokes 5 and 6 are arranged in a plane perpendicular to the axial direction of the magnetostrictive ring 2 in parallel with O, and the positions on the straight line passing through the centers of their thicknesses are two magnetic sensors 3A. , 3B and the center axis XX. When the inner yoke 4 and the outer yokes 5 and 6 are not arcuate, the thickness centers of the inner yoke 4 and the outer yokes 5 and 6 may be aligned with the central axis XX.

 As described above, in this embodiment, the two magnetic sensors 3A and 3B, the inner yoke 4, and the outer yokes 5 and 6 are arranged on a plane perpendicular to the central axis OO of the magnetostrictive ring 2, and By arranging each center line passing through the two magnetic sensors 3 </ b> A and 3 </ b> B to be substantially parallel and coincide with the center axis XX that is substantially parallel to the axis of the rotary shaft 1, The magnetic resistance passing through the magnetic sensors 3A and 3B is reduced, the probability that an external noise magnetic field such as geomagnetism will pass through the two magnetic sensors 3A and 3B at the same time is very high, and the output of the two magnetic sensors 3A and 3B. It is possible to cancel the difference by the difference between the two, and errors due to external noise can be reduced.

[Embodiment 11]
FIG. 17 is a perspective view showing the entire configuration of the torque sensor device according to the eleventh embodiment of the present invention, and FIG. 18 is a plan view having a cross section of the main part showing the entire configuration of the torque sensor device according to the eleventh embodiment of the present invention. .

 In FIG. 17 and FIG. 18, the characteristic point is that the common central axis XX of the two magnetic sensors 3A and 3B is arranged in parallel around the magnetostrictive ring 2 and the central axis O− of the rotary shaft 1 is. They are arranged apart in the length direction of O. Specifically, although they are not concentric with each other, they are in the same axial direction parallel to the axial direction of the axis of the rotary shaft 1.

 Further, the inner yoke 400 disposed between the two magnetic sensors 3A and 3B in the approximate center in the axial direction of the magnetostrictive ring 2 is formed in a substantially T-shaped cross section, and has a lower end having a substantially T-shaped cross section. That is, since the end of the inner peripheral plane portion 402 can be set as a boundary between the magnetized portion 2A and the magnetized portion 2B of different magnetic poles, the length of the magnetic pole formed on the magnetostrictive ring 2 in the axial direction of the rotating shaft 1 is set. The change in the magnetic field in the axial direction of the rotary shaft 1 from the magnetic poles of the magnetized portion 2A and the magnetized portion 2B formed on the magnetostrictive ring 2 can be detected efficiently by the two magnetic sensors 3A and 3B. Here, the magnetic resistance can be lowered as the thickness of the substantially T-shaped cross section increases. However, since the lower end having a substantially T-shaped cross section, that is, the end of the inner peripheral plane portion 402 is set at the magnetic pole boundary, the magnetized portion 2A formed on the magnetostrictive ring 2 and the magnetized portion when the thickness is large. A loss of the magnetic pole length of the axial direction length of the rotating shaft 1 of the part 2B occurs. The annular cylindrical portion 401 having a substantially T-shaped cross section is determined by the thicknesses of the two magnetic sensors 3A and 3B, the distance between them, and the like.

 In the present embodiment, the inner yoke 400 sandwiched between the magnetic sensor 3A and the magnetic sensor 3B has a lower magnetic resistance between the magnetic sensor 3A and the magnetic sensor 3B. Specifically, the protrusion 4a is formed on the inner yoke 400 to reduce the magnetic resistance with the magnetic sensor 3A. Similarly, the protrusion 4b is formed on the inner yoke 400 to reduce the magnetic resistance with the magnetic sensor 3B. The gaps between the protrusions 4a, 4b of the inner yoke 400 and the magnetic sensors 3A, 3B are integrally joined to suppress the magnetic resistance to a minimum.

 In the outer yoke 500 and the outer yoke 600, the annular flat portions 502 and 602 are set as outer end portions of the magnetic poles, and the end portions of the outer periphery of the magnetostrictive ring 2 are opposed to the magnetic sensors 3A and 3B. , 601 are formed. The annular flat portions 502 and 602 and the annular cylindrical portions 501 and 601 form a substantially L-shaped cross section.

 In this case, the outer yoke 500 and the outer yoke 600 can increase the axial length of the rotating shaft 1 of the magnetic pole formed on the magnetostrictive ring 2, and the magnetic field in the axial direction of the rotating shaft 1 can be increased from the magnetic pole formed on the magnetostrictive ring 2. Changes can be detected efficiently. Moreover, since the thickness of the outer yoke 500 and the outer yoke 600 may protrude from the end of the magnetostrictive ring 2, it can be set to an arbitrary thickness, and the magnetic resistance can be arbitrarily reduced.

 In the present embodiment, the outer yoke 500 facing the magnetic sensor 3A or the outer yoke 600 facing the magnetic sensor 3B is configured to reduce the magnetic resistance between the magnetic sensor 3A and the magnetic sensor 3B. . Specifically, the protrusion 5a is formed on the outer yoke 500 to reduce the magnetic resistance with the magnetic sensor 3A, and similarly, the protrusion 6b is formed on the outer yoke 600 and the magnetic resistance with the magnetic sensor 3B. Is low. The gaps between the protrusions 4a and 4b of the inner yoke 400 and the outer yokes 500 and 600, the protrusions 5a and 6a, and the magnetic sensors 3A and 3B are integrally joined to suppress the magnetic resistance to a minimum.

 The inner yoke 400 and the outer yokes 500 and 600 are arranged in a plane perpendicular to the axial direction of the magnetostrictive ring 2 in parallel to the axial centers (center axes OO) of the inner yoke 400 and the outer yokes 500 and 600. The position on the straight line passing through the center of the thickness of the two magnetic sensors 3A and 3B coincides with the central axis XX of the two magnetic sensors 3A and 3B. When the inner yoke 400 and the outer yokes 500 and 600 are not arcuate, the thickness centers of the inner yoke 400 and the outer yokes 500 and 600 may be aligned with the central axis XX.

 Further, the protrusions 4a and 4b of the inner yoke 400, the protrusion 5a of the outer yoke 500, and the protrusion 6b of the outer yoke 600 are disposed substantially parallel to the axial direction of the magnetostrictive ring 2, and these protrusions 4a, 4b, Each central axis passing through the center of the cross section of the protrusion 5a and protrusion 6b (cross section perpendicular to the axial direction of the magnetostrictive ring 2) has a position on the straight line that is the central axis XX of the two magnetic sensors 3A and 3B To match (substantially parallel).

 As described above, the two magnetic sensors 3A and 3B, the inner yoke 400, the outer yokes 500 and 600, the protrusions 4a and 4b of the inner yoke 400, the protrusion 5a of the outer yoke 500, and the protrusion 6b of the outer yoke 600 according to the present embodiment. Are arranged in a plane perpendicular to the central axis OO of the magnetostrictive ring 2 and the central line passing through the two magnetic sensors 3A, 3B is parallel to the central axis of the rotary shaft 1 X- By arranging to match X, the magnetic resistance passing through the two magnetic sensors 3A, 3B is reduced, and the probability that a magnetic field of external noise such as geomagnetism passes through the two magnetic sensors 3A, 3B simultaneously is increased. It can be made very high and can be canceled by the difference between the outputs of the two magnetic sensors 3A and 3B, and errors due to external noise can be reduced.

 That is, when the present invention is implemented, the protrusions 4a and 4b of the inner yoke 400, the protrusion 5a of the outer yoke 500, and the protrusion 6b of the outer yoke 600 are straight lines passing through the centers of the two magnetic sensors 3A and 3B. What is necessary is just to be substantially parallel and arrange | positioned substantially parallel to the central axis OO of the rotating shaft 1. FIG.

 Further, the axial centers of the protrusion 4a of the inner yoke 400, the protrusion 5a of the outer yoke 500, and the protrusion 6b of the outer yoke 600 are disposed at positions passing through the central axes XX of the two magnetic sensors 3A and 3B. A magnetic path having a low magnetic resistance is formed by a material having a high magnetic permeability that forms a magnetic path between the sensor 3A and the magnetic sensor 3B and the inner yoke 400 and the outer yokes 500 and 600.

 Between the inner yoke 400 and the outer yokes 500 and 600, a protrusion 4a of the inner yoke 400, a protrusion 5a of the outer yoke 500, a protrusion 6b of the outer yoke 600, and two magnetic sensors 3A or 3B are disposed. As a result, even if the inner yoke 400 and the outer yokes 500 and 600 are separated from each other, the projection 4a of the inner yoke 400, the projection 5a of the outer yoke 500, and the projection 6b of the outer yoke 600 are separated from the magnetic sensor 3A. Since the magnetic resistance of the portion where the magnetic sensor 3B is disposed is low, the magnetic resistance of the magnetic resistance is low with the protrusion 4a, the inner yoke 400, the magnetized portion 2A of the magnetostrictive ring 2 and the outer yoke 500, and the protrusion 5a as magnetic paths. A circuit is formed. Similarly, a magnetic circuit having a low magnetic resistance is formed using the protrusion 4b, the inner yoke 400, the magnetized portion 2B of the magnetostrictive ring 2 and the outer yoke 600, and the protrusion 6a as magnetic paths.

 In particular, the protrusions 4a, 5a, and 6b on the side facing the two magnetic sensors 3A and 3B of the inner yoke 400 and the outer yokes 500 and 600 of the present embodiment are the inner yoke 400 and the outer yokes 500 and 600, respectively. The two magnetic sensors 3A, 3B are arranged in a linear position passing through the protruding structure on the side facing the two magnetic sensors 3A, 3B and parallel to the central axis OO of the rotating shaft 1. The magnetic resistance passing through 3B is reduced, the probability that a magnetic field of external noise such as geomagnetism will pass through the two magnetic sensors 3A, 3B at the same time is very high, and the difference between the outputs of the two magnetic sensors 3A, 3B Can be offset, and errors due to external noise can be reduced.

 Further, the projection 4a, the projection 5a, and the projection 6b on the side facing the two magnetic sensors 3A and 3B of the inner yoke 400 and the outer yoke 500 and 600 of the present embodiment are the axes of the two magnetic sensors 3A and 3B. The opposing areas and magnetic materials facing both sides in the direction are made substantially the same, and the change in magnetoresistance before and after the passage of the two magnetic sensors 3A, 3B in the axial magnetic field of the two magnetic sensors 3A, 3B is reduced. In this structure, the external noise is a magnetic resistance that easily passes through the two magnetic sensors 3A and 3B.

 Accordingly, the magnetic resistance passing through the magnetic sensors 3A and 3B can be reduced, the conditions on the magnetic flux input sides and output sides of the magnetic sensors 3A and 3B can be made substantially the same, and external noise easily passes through the magnetic sensors 3A and 3B. Since it can be structured, it is possible to increase the probability that a magnetic field of external noise such as geomagnetism passes through the magnetic sensors 3A and 3B at the same time, and the influence of the external noise can be offset by the outputs of the magnetic sensors 3A and 3B.

 The inner yoke 400 is formed in a substantially T-shaped cross section, and the inner end portion of the inner peripheral plane portion 402 can be set as a boundary between the magnetized portion 2A and the magnetized portion 2B of different magnetic poles. Since the magnetic pole lengths of the magnetized portion 2A and the magnetized portion 2B formed in the above can be utilized to the maximum, the change in the magnetic field in the axial direction of the rotary shaft 1 can be efficiently performed by the two magnetic sensors 3A and 3B Can be detected.

 The outer yoke 500 and the outer yoke 600 can also utilize the lengths of the magnetic poles of the magnetized portion 2A and the magnetized portion 2B formed on the magnetostrictive ring 2 to the maximum extent. Thus, the change in the magnetic field in the axial direction of the rotary shaft 1 can be detected efficiently. In particular, the thicknesses of the outer yoke 500 and the outer yoke 600 may protrude from the end of the magnetostrictive ring 2, so that they can be set to any thickness, the magnetic resistance can be arbitrarily reduced, and the sensitivity is increased. be able to.

[Embodiment 12]
FIG. 19 is a plan view having a cross-section of the main part showing the overall configuration of the torque sensor device according to the twelfth embodiment of the present invention.

 In FIG. 19, the feature of this embodiment is that the outer yoke 500 and the outer yoke 600 are formed by extending annular flat portions 503 and 603 in the outer peripheral direction of the rotary shaft 1 outside the end of the magnetostrictive ring 2. It is. As a result, the annular plane portions 503 and 603 and the annular cylindrical portions 501 and 601 form a substantially L-shaped cross section through the central axis OO of the rotating shaft 1.

 In this case, the outer yoke 500 and the outer yoke 600 are configured such that the annular plane portions 503 and 603 cover the outside of the end portion of the magnetostrictive ring 2 so that the magnetic pole formed on the magnetostrictive ring 2 has the axial length of the rotary shaft 1. That is, a large amount of magnetic flux can be secured, and a change in the magnetic field in the axial direction of the rotating shaft 1 can be efficiently detected from the magnetic pole formed on the magnetostrictive ring 2. Moreover, since the thickness of the outer yoke 500 and the outer yoke 600 may protrude from the end of the magnetostrictive ring 2, it can be set to an arbitrary thickness, and the magnetic resistance can be arbitrarily reduced.

 In addition, since the annular flat surface portions 503 and 603 efficiently pass the external noise through the two magnetic sensors 3A and 3B, it functions as a shield and does not leak to the other, so that the external noise can be canceled. Easy.

 As described above, the torque sensor device according to the above embodiment has the inner yoke 4 or the semicircular inner yokes 4A and 4B or the semicircular inner yoke 40 made of a material having a high magnetic permeability between the two magnetic sensors 3A and 3B. Alternatively, the sensor inner yokes 8Ab, 8Ba allow the two magnetic sensors 3A, 3B to pass the same external noise and correspond to the two poles magnetized in different axial directions. , 3B is used for differential detection, so even if external noise in the axial direction of the rotating shaft 1 arrives, it can be canceled by the difference between the outputs of the two magnetic sensors 3A, 3B. The influence of external noise such as geomagnetism that enters through the gap between the shaft 1 and the shield member can be eliminated, and the S / N ratio can be increased. Also, the inner yoke 4 or the semicircular inner yokes 4A and 4B or the semicircular inner yoke 40 or the sensor inner yokes 8Ab and 8Ba, the outer yoke 5 and the outer yoke 6, or the semicircular outer yokes 5A and 5B and the semicircular ring. Since the outer yoke 6A, 6B or the semi-circular outer yoke 50, the semi-circular outer yoke 60, the sensor outer yoke 8Aa, and the sensor outer yoke 8Bb can induce the magnetization change of the magnetostrictive ring 2 to the magnetic sensors 3A, 3B. It is possible to accurately detect the magnetization change of the ring 2 and increase the amount of change.

 Here, if the facing area can be maintained, the inventors have confirmed that there is no problem in the structure of the torque sensor device if a material having good magnetic permeability is used even if the facing volume is not substantially the same. That is, in the torque sensor device of the above-described embodiment, the above-described inner yoke is disposed with substantially the same facing area and magnetic material facing the two axial sides of the two magnetic sensors 3A and 3B.

FIG. 1 is a perspective view showing the overall configuration of the torque sensor device according to the first embodiment of the present invention. FIG. 2 is a plan view showing the overall configuration of the torque sensor device according to the first embodiment of the present invention. FIG. 3 is a detection circuit diagram from two magnetic sensors of the torque sensor device according to the first embodiment of the present invention. FIG. 4 is an actual measurement characteristic diagram of the torque sensor device according to the first embodiment of the present invention. FIG. 5 is an explanatory view showing a planar arrangement structure of the two magnetic sensors, the inner yoke and the outer yoke of Examples (a) to (d) in the torque sensor device according to the second embodiment of the present invention. FIG. 6 is an explanatory view showing a protrusion front structure of two magnetic sensors, an inner yoke, and an outer yoke of an example in the torque sensor device according to the second embodiment of the present invention. 7A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke, and an outer yoke in the torque sensor device according to the third embodiment of the present invention, and FIG. 7B shows a side arrangement structure. It is explanatory drawing. 8A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke, and an outer yoke in the torque sensor device according to the fourth embodiment of the present invention, and FIG. 8B shows a side arrangement structure. It is explanatory drawing. FIG. 9A is an explanatory view showing a planar arrangement structure of two magnetic sensors, an inner yoke and an outer yoke in the torque sensor device according to the fifth embodiment of the present invention, and FIG. 9B is one magnetic sensor. FIG. 9C and FIG. 9C are side views thereof. FIG. 10A is a front view of one magnetic sensor in the torque sensor device according to Embodiment 6 of the present invention, and FIG. 10B is a side view thereof. FIG. 11A is a front view of one magnetic sensor in the torque sensor device according to Embodiment 7 of the present invention, and FIG. 11B is a side view thereof. FIG. 12A is a front view of one magnetic sensor in the torque sensor device according to the eighth embodiment of the present invention, and FIG. 12B is a side view thereof. FIG. 13 is a plan view showing a planar structure of two magnetic sensors in the torque sensor device according to the ninth embodiment of the present invention. FIG. 14A is a front explanatory view showing the configurations of the magnetostrictive ring and the yoke in the torque sensor device according to the ninth embodiment of the present invention, and FIG. 14B is an explanatory view showing the right side view thereof. FIG. 15 is a perspective view showing the overall configuration of the torque sensor device according to the tenth embodiment of the present invention. FIG. 16 is a plan view showing the overall configuration of the torque sensor device according to the tenth embodiment of the present invention. FIG. 17 is a perspective view showing the overall configuration of the torque sensor device according to the eleventh embodiment of the present invention. FIG. 18 is a plan view having a cross section of the main part showing the overall configuration of the torque sensor device according to the eleventh embodiment of the present invention. FIG. 19 is a plan view having a cross-section of the main part showing the overall configuration of the torque sensor device according to the twelfth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Magnetostrictive ring 2A, 2B Magnetized part 3 (3A, 3B) Magnetic sensor 4 Inner yoke 5,6 Outer yoke 4a-4h, 5a-5d, 6a-6d Protrusion OP Differential amplification circuit 8Aa, 8Bb Sensor outer side Yoke 8Ab, 8Ba Sensor inner yoke 30 Detection circuit 40 Semi-annular inner yoke 50, 60 Semi-annular outer yoke 80 Connection yoke 81 Bent portion

Claims (12)

Adjacent sections fixed to the rotating shaft and magnetized in opposite directions in the circumferential direction are parallel to the axial direction of the rotating shaft (the length direction of the shaft) according to the torque applied to the rotating shaft. A magnetostrictive ring that generates a magnetic field that
The two magnetic sensors corresponding to the magnetic poles of the two sections formed in the magnetostrictive ring and disposed along the axial direction of the rotation axis;
An inner yoke disposed between the two magnetic sensors and at a magnetic pole boundary formed in the magnetostrictive ring;
A pair of outer yokes disposed outside the two magnetic sensors and forming a magnetic path between the inner yokes corresponding to the two magnetic sensors;
A torque sensor device comprising: a detection circuit that detects a difference between outputs of the magnetic sensors that detect magnetic fields of the different magnetic poles.  The torque sensor device according to claim 1, wherein the inner yoke is formed with a common magnetic path for the two magnetic sensors.  3. The torque sensor device according to claim 1, wherein the inner yoke has a substantially quadrangular cross section through a central axis of the rotation shaft.  3. The torque sensor device according to claim 1, wherein the inner yoke has a substantially T-shaped cross section through a central axis of the rotation shaft.  5. The torque sensor device according to claim 1, wherein a cross section of the outer yoke passing through a central axis of the rotation shaft is formed in a substantially square shape.  The torque sensor device according to any one of claims 1 to 4, wherein the outer yoke has a substantially L-shaped cross section through a central axis of the rotation shaft.  7. The torque according to claim 5, wherein the outer yoke is formed so that a cross section passing through a central axis of the rotation shaft has a smaller diameter than a diameter of an end face of the magnetostrictive ring. Sensor device.  The torque sensor device according to any one of claims 1 to 7, wherein the inner yoke and the outer yoke are formed with arcuate opposing surfaces around the magnetostrictive ring.  The whole of the inner yoke and the outer yoke attached around the rotating shaft is formed in a substantially rectangular parallelepiped shape, wherein the inner yoke and the outer yoke are formed in a substantially rectangular parallelepiped shape. The torque sensor device according to any one of 8.  The inner yoke and the outer yoke are arranged so that a straight line passing through the centers of the two magnetic sensors is substantially parallel and substantially parallel to the axis of the rotation shaft. The torque sensor device according to any one of 9.  The torque sensor device according to any one of claims 1 to 10, wherein the inner yoke and the outer yoke each include a protrusion protruding toward the magnetic sensor side. The projections on the side of the inner yoke and the outer yoke facing the magnetic sensor are substantially parallel to a center passing through the center of the magnetic sensor and the centers of the projections of the inner yoke and the outer yoke, and the rotation shaft. The torque sensor device according to claim 11, wherein the torque sensor device is disposed at a position substantially parallel to the axis of the torque sensor.

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