CN102980698B - Magnetostrictive torque sensor - Google Patents
Magnetostrictive torque sensor Download PDFInfo
- Publication number
- CN102980698B CN102980698B CN201210286981.1A CN201210286981A CN102980698B CN 102980698 B CN102980698 B CN 102980698B CN 201210286981 A CN201210286981 A CN 201210286981A CN 102980698 B CN102980698 B CN 102980698B
- Authority
- CN
- China
- Prior art keywords
- magnetic shield
- turning axle
- magnetic
- coil
- magnetostrictive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Power Steering Mechanism (AREA)
Abstract
The invention provides a kind of magnetostrictive torque sensor that can suppress the reduction of detection sensitivity.Magnetostrictive torque sensor (41) possesses: the turning axle (24) with mangneto pars contractiliss such as magnetostrictive films (82); Magnetostrictive film (82) is carried out to the field coil (85,85) of excitation; To the magnetic test coil (85,85) that the change of the magnetic characteristics such as the magnetoconductivity of magnetostrictive film (82) detects; At least surround the magnetic shield (54a) of the surrounding of field coil (85,85).Turning axle (24) is made up of magnetic material.Magnetic shield (54a) also surrounds around the part of the turning axle (24) without magnetostriction portion (82).Magnetic shield (54a) has the slit (54as) parallel with the central shaft of turning axle (24) (CL) in the part corresponding with field coil (85,85).
Description
Technical field
The present invention relates to a kind of magnetostrictive torque sensor.
Background technology
The vehicles such as motor vehicle can possess driven steering device, and driven steering device produces the assist torque turning to torque to assist to the turning axle place produced to the operation of steering wheel (bearing circle) by driver.By the generation of assist torque, driven steering device can alleviate the burden of driver.Driven steering device has and turns to torque sensor to what turn to torque to detect, can be categorized as the torque sensor (magnetostrictive torque sensor) utilizing magnetostrictive effect to detect torque, the torque sensor etc. utilizing torque arm to detect torque to the torque sensor that effect torques on the rotary shaft such as turning to torque detects.
Such as patent documentation 1 discloses the magnetostrictive torque sensor that can utilize in driven steering device, in this magnetostrictive torque sensor, the magnetic shield 20a as shown in Figure 3 as patent documentation 1 is arranged near lid (retaining member) 43.In addition, in Fig. 5 (b) of patent documentation 1, lid (retaining member) 43 self doubles as magnetic shield.The magnetostrictive torque sensor possessing such magnetic shield is difficult to the impact of the external magnetic field noise (external magnetic field noise) be subject to from outside.Thus, magnetic shield can make the accuracy of detection of magnetostrictive torque sensor improve.
[at first technical literature]
[patent documentation]
[patent documentation 1] Japanese Unexamined Patent Publication 2004-309184 publication
But when being configured with magnetic shield 20a near field coil 20d ', the 20e ' as shown in Figure 3 of patent documentation 1, the present inventors have found that situation about reducing occurs the detection sensitivity of magnetostrictive torque sensor.That is, under the impact of magnetic shield 20a, the inclination as the straight line L10 as shown in Figure 7 of patent documentation 1 diminishes.
In addition, the steering axle 12b as shown in Figure 3 of patent documentation 1 externally exposes.Thus, the present inventors have found enter turning axle 12 from the external magnetic field noise on the top of steering axle 12b and make the situation that the accuracy of detection of magnetostrictive torque sensor reduces.
Summary of the invention
One object of the present invention is to provide a kind of magnetostrictive torque sensor that can suppress the reduction of detection sensitivity.Another object of the present invention is to provide a kind of magnetostrictive torque sensor that can suppress the reduction of accuracy of detection.The form that other objects of the present invention exemplify by referring to following, preferred embodiment and accompanying drawing, make the art personnel clearly.
Below, exemplify according to mode of the present invention in order to easy understand overview of the present invention.
Relate to a kind of magnetostrictive torque sensor according to the 1st aspect of the present invention, it possesses:
There is the turning axle in magnetostriction portion;
Described magnetostriction portion is carried out to the field coil of excitation;
To the magnetic test coil that the change of the magnetic characteristic in described magnetostriction portion detects;
At least surround the magnetic shield of the surrounding of described field coil,
The feature of described magnetostrictive torque sensor is,
Described turning axle is made up of magnetic material,
Described magnetic shield also surrounds around the part of the described turning axle without described magnetostriction portion,
Described magnetic shield has the slit parallel with the central shaft of described turning axle in the part corresponding with described field coil.
Around the part of being surrounded the turning axle without magnetostriction portion by magnetic shield, the external magnetic field noise entering into the inside of turning axle thus from the top of turning axle can shift to magnetic shield side.Consequently, the magnetic flux (the external magnetic field noise towards coil) in turning axle reduces.Thereby, it is possible to suppress the reduction of the accuracy of detection of magnetostrictive torque sensor.
In addition, magnetic shield at least surrounds around field coil, thus can suppress the external magnetic field noise in other directions beyond from the top of turning axle.But the magnetic flux produced by field coil reduces because flowing through the vortex flow of magnetic shield, consequently, makes the detection sensitivity of magnetostrictive torque sensor reduce.To this, magnetic shield has slit in the part corresponding with field coil, thus suppresses the reduction of detection sensitivity by slit.
It should be noted that, field coil and magnetic test coil can be made up of dual-purpose coil, also can be made up of the combination of special field coil and special magnetic test coil.
In first method, magnetic shield can have cylindric shape.
Have cylindric shape by magnetic shield, the external magnetic field noise transferring to magnetic shield side is advanced on the complete cycle of magnetic shield with cylindric shape.Thus, the impact of external magnetic field noise can be reduced.
In first method, described magnetic shield can have annular portion to replace described slit in the part corresponding with the described part of the described turning axle without described magnetostriction portion, and the distance between the part of the described magnetic shield opposed with described field coil and described central shaft can than the distance between described annular portion and described central shaft.
Because annular portion surrounds the part without the turning axle in magnetostriction portion, the external magnetic field noise therefore entering into the inside of turning axle from the top of turning axle easily shifts to annular portion (magnetic shield) side.In addition, the magnetic flux transferring to magnetic shield side (annular portion side) from rotation shaft side in magnetic shield (part of the magnetic shield opposed with field coil) through time, can make this magnetic flux away from field coil by the part of the magnetic shield opposed with field coil.Thereby, it is possible to reduce the impact of the external magnetic field noise passed in magnetic shield.
The art personnel can easily understand, what exemplify can change when not departing from spirit of the present invention further according to mode of the present invention.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the driven steering device with magnetostrictive torque sensor.
Fig. 2 is the one-piece construction figure of the driven steering device shown in Fig. 1.
Fig. 3 is the 3-3 line cut-open view of Fig. 2.
Fig. 4 is the enlarged drawing near the magnetic shield of Fig. 3.
Fig. 5 is the magnetic shield of Fig. 3 and the stereographic map of sensor housing.
Fig. 6 is the enlarged drawing of the variation of the magnetic shield representing Fig. 3.
Symbol description:
10 ... driven steering device
20 ... steering
21 ... steering wheel
22 ... steering axle
23 ... universal shaft joint
24 ... turning axle
24a ... one end
24b ... the other end
24i ... linking part
25 ... pinion and rack
26 ... rack shaft
27 ... drag link
28 ... steering knuckle
29 ... steered wheel
31 ... pinion wheel
32 ... tooth bar
40 ... assist torque mechanism
41 ... turn to torque sensor
42 ... control part
43 ... motor
44 ... reducing gear
45 ... worm shaft
46 ... worm screw
47 ... worm gear
51 ... housing
51a ... upper opening
52 ... ball-and-socket joint
53 ... dust seal guard shield
54a ... magnetic shield
54as ... slit
54b ... magnetic shield
55 ... sensor housing
56 ... oil sealing
57 ... screw
58 ... bolt
61 ... clutch shaft bearing
62 ... second bearing
70 ... rack guide
71 ... guide portion
72 ... Compress Spring
73 ... adjustment bolt
74 ... abut component (Japanese: when て portion material)
75 ... set nut
81 ... magnetostriction portion
82 ... magnetostriction portion
83 ... test section
84 ... coil rack
85 ... coil
92 ... connector
Embodiment
Below illustrate preferred embodiment for making easy understand of the present invention.Thus, the art personnel should give it is noted that the present invention is not limited unreasonably by the embodiment of following explanation.
Fig. 1 schematically shows the driven steering device 10 turning to torque sensor 41 be incorporated with as magnetostrictive torque sensor.Driven steering device 10 comprises: from the steering 20 of the steered wheel (front-wheel) 29,29 of steering wheel 21 to the vehicle of vehicle; This steering 20 is applied to the assist torque mechanism 40 of assist torque, i.e. additional torque.
In steering 20, steering wheel 21 links turning axle 24 (being also referred to as " pinion shaft, input shaft ") via steering axle 22 and universal shaft joint 23,23, turning axle 24 links rack shaft 26 via pinion and rack 25, links the steered wheel 29,29 of left and right at the two ends of rack shaft 26 via the drag link 27,27 of left and right and steering knuckle 28,28.Pinion and rack 25 comprises: the pinion wheel 31 had on turning axle 24; The tooth bar 32 that rack shaft 26 has.
According to steering 20, by driver, steering wheel 21 is turned to, thus can torque be turned to by this and via pinion and rack 25, steered wheel 29,29 be turned to.
Assist torque mechanism 40 is mechanisms as follows, namely, detect by turning to the torque that turns to of torque sensor 41 to the steering 20 being applied to steering wheel 21, control signal is produced by control part 42 according to this detection signal, and produced and the assist torque turning to torque corresponding (additional torque) by motor 43 according to this control signal, assist torque is transmitted to turning axle 24 via reducing gear 44, and then assist torque is transmitted from turning axle 24 to the pinion and rack 25 of steering 20.
Motor 43 is such as made up of brushless motor, and it is built-in with the rotation sensors such as resolver.The rotation angle of this rotation sensor to the rotor in motor 43 detects.
The overview of control part 42 is described, as described below.
Control part 42 is by power circuit, form current sensor, input interface circuit, microprocessor, output interface circuit, FET bridge circuit etc. that motor current detects.Input interface circuit is taken into dtc signal, vehicle speed signal or motor rotating signal etc. from outside.Microprocessor, according to the dtc signal be taken into by input interface circuit or vehicle speed signal etc., carries out vector controlled to motor 43.Output interface circuit converts the output signal of microprocessor to drive singal to FET bridge circuit.FET bridge circuit is the on-off element passing into three-phase alternating current to motor 43 (brushless motor).
Such control part 42, according to the rotating signal of the rotor of the motor 43 detected by rotation sensor and the current signal that detected by motor current sensor (being built in control part 42), carries out vector controlled.This vector controlled is that d-q controls, and carries out DC control to the q shaft current of torque and the d shaft current of controlling magnetic field controlling motor 43.
Namely, control part 42, according to by the rotating signal etc. of rotor turning to dtc signal, the vehicle speed signal detected by not shown vehicle speed sensor and detected by rotation sensor turning to torque sensor 41 to detect, comes target setting q shaft current and target d shaft current.
Then, control part 42, according to the rotating signal detected by rotation sensor and the current signal detected by motor current sensor, carries out PI control to make the actual q shaft current after carrying out d-q conversion and the actual d shaft current mode consistent with above-mentioned target q shaft current and target d shaft current.
According to driven steering device 10, by turning to the assist torque (additional torque) torque adding upper motor 43 and the compound torque obtained driver, can utilize rack shaft 26 that steered wheel 29,29 is turned to.
Reducing gear 44 is such as made up of Worm gear mechanism.Below, reducing gear 44 is suitably renamed as " Worm gear mechanism 44 ".
Fig. 2 shows the one-piece construction of the driven steering device 10 shown in Fig. 1, and it is the figure that left part and right part are cut open and illustrated.As shown in Figure 2, rack shaft 26 is housed in the mode that can axially slide in the housing 51 extended along overall width direction (left and right directions of Fig. 2).In rack shaft 26, be linked with drag link 27,27 at the length direction two ends outstanding from housing 51 via ball-and-socket joint 52,52.The both ends of rack shaft 26 are covered by dust seal guard shield 53,53.
As shown in Figures 2 and 3, housing 51 receives the latter half of turning axle 24, pinion and rack 25 and Worm gear mechanism 44, and the upper opening 51a formed in upper end is provided with magnetic shield 54b.The opposition side relative to upper opening 51a of such housing 51, i.e. bottom are inaccessible.
Be described in further detail, as shown in Figure 3, turning axle 24 configures in the mode erected in the inside of housing 51, and is provided with two the magnetostriction portions 81,82 clutch shaft bearing 61, pinion wheel 31, second bearing 62, magnetostrictive torque sensor 41 successively from one end 24a (lower surface) towards other end 24b (upper surface).
Turning axle 24 is under the state of inside being installed on housing 51, and the first half extends upward from the through sensor housing 55 of upper opening 51a.Two magnetostriction portions 81,82 are positioned at sensor housing 55.
As shown in Figure 3, turning axle 24 supports as rotating via clutch shaft bearing 61 and the second bearing 62 by housing 51 on inner peripheral surface.That is, the end portion of turning axle 24 is supported as rotating by housing 51 via clutch shaft bearing 61.Position between the pinion wheel 31 and worm gear 47 of the center section of turning axle 24 is supported as rotating by housing 51 via the second bearing 62.In figure 3, CL is the center line (axle center) of turning axle 24.
Sensor housing 55 is received turning to torque sensor 41 (test section 83), and sensor housing 55 is surrounded by magnetic shield 54a, 54b.Sensor housing 55 is made up of nonmagnetic substances such as resins.The through sensor housing of turning axle 24 55 upper and lower, and the oil sealing 56 for sealing turning axle 24 is provided with on the top of sensor housing 55.In the example in figure 3, magnetic shield 54a (the first magnetic shield) is such as formed as tubular, surround such as coil 85,85 and magnetostriction portion 82 around via such as sensor housing 55 and oil sealing 56, and also surround turning axle 24 (not having the part of the turning axle 24 in magnetostriction portion 82) between magnetostriction portion 82 and linking part 24i around.In the example in figure 3, magnetic shield 54b (the second magnetic shield) is such as formed as tubular, and forms flange.Magnetic shield 54b surrounds such as coil 85,85 and magnetostriction portion 81 around.
In the example in figure 3, magnetic shield is made up of these two components of magnetic shield 54a and magnetic shield 54b, but also can such as be made up of a component.For magnetic shield 54a and magnetic shield 54b, describe later.
Magnetic shield 54a is fixed on sensor housing 55 by screw 57, and magnetic shield 54b (flange) is installed by bolt 58.Relative to housing 51, sensor housing 55 is limited to the movement of radial direction via magnetic shield 54b.
In figure 3, motor 43 is components that not shown motor reel flatly extends from the opposite side of paper to side, front in housing 51.Motor reel is the output shaft of the worm shaft 45 having linked Worm gear mechanism 44.Worm shaft 45 possesses the worm screw 46 be integrally formed.The both ends of worm shaft 45 are supported as rotating by housing 5 via bearing.
Worm gear mechanism 44 is configured to, and is engaged by the worm screw 46 of the worm gear 47 with driving side that make slave end, and from worm screw 46 via worm gear 47 to load-side transmitting torque.
Housing 51 possesses rack guide 70.This rack guide 70 comprises: the guide portion 71 offseted from opposition side and the rack shaft 26 of tooth bar 32; The adjustment bolt 73 of guide portion 71 is pressed via Compress Spring 72; What supply the Dorsal glide of rack shaft 26 abuts component 74; To the set nut 75 that adjustment bolt 73 positions.
Turn to torque sensor 41 to be magnetostrictive torque sensors, it comprises: turning axle 24; Be arranged on the surface of this turning axle 24, the magnetostriction portion 81,82 of a pair up and down that Magnetostrictive Properties (magnetic characteristic) changes according to torque; Be configured in this magnetostriction portion 81,82 vicinity and to the coil 85,85,85,85 that detects of magnetostrictive effect produced in magnetostriction portion 81,82.
In other words, torque sensor 41 is turned to comprise: to be arranged on a pair magnetostriction portion 81,82 on turning axle 24; Be arranged on the test section 83 of the surrounding in magnetostriction portion 81,82.
Magnetostriction portion 81,82 is such as made up of the magnetostrictive film being endowed reciprocal residual deformation each other on the shaft length direction of turning axle 24.Below, magnetostriction portion 81,82 is suitably renamed as " magnetostrictive film 81,82 ".
Magnetostrictive film 81,82 is the films be made up of the material that the change of magnetic flux density relative to the change of being out of shape is large, such as, for being formed in the alloy film of the Ni-Fe system on the outer peripheral face of turning axle 24 by vapour deposition process.The thickness of this alloy film is preferably about 30 ~ 50 μm.It should be noted that, the thickness of alloy film also can be below this scope or more than this scope.The magnetostriction direction of the second magnetostrictive film 82 is relative to the magnetostriction direction difference (having magnetostriction anisotropy) of the first magnetostrictive film 81.Like this, two magnetostrictive films 81,82 are the roughly fixing width and the film of fixing thickness that complete cycle is formed on the outer peripheral face of turning axle 24.It should be noted that, two magnetostrictive films 81,82 have the interval of regulation and arrange on shaft length direction.
When the alloy film of Ni-Fe system roughly contains the Ni of 50 % by weight, magnetostriction constant becomes large, therefore there is the tendency that magnetostrictive effect uprises, thus preferably uses the material of such Ni containing ratio.Such as, as the alloy film of Ni-Fe system, use Ni containing 50 ~ 70 % by weight and remaining as the material of Fe.
It should be noted that, magnetostrictive film 81,82 also can be the film of ferromagnetic, is not limited to the alloy film of Ni-Fe system.Such as, magnetostrictive film 81,82 also can be the alloy film of Co-Fe system or the alloy film of Sm-Fe system.
Test section 83 carries out electro-detection to the magnetostrictive effect produced on magnetostrictive film 81,82, and is exported as Torque test signal by its detection signal, and this test section 83 is accommodated in sensor housing 55.This test section 83 comprises: the coil rack 84 of the tubular that turning axle 24 is through; Multilaminate coiled coil 85,85,85,85 on coil rack 84.By using four coils 85,85,85,85 as magnetic test coil, detection signal can not only comprise Torque test signal thus, also can comprise fault detection signal.It should be noted that, the magnetic flux from four magnetic test coils 85,85,85,85 carries out excitation to magnetostrictive film 81,82, and four magnetic test coils 85,85,85,85 also play a role as four field coils.Four coils 85,85,85,85 can be called the field coil of dual-purpose magnetic test coil respectively.That is, in the example in figure 3, four coils 85,85,85,85 are respectively dual-purpose coil.
The gap of magnetostrictive film 81,82 and coil rack 84 is set in the scope of about 0.5 ~ 1mm.Coil 85,85,85,85 in the scope of 1 ~ 100kHz by with the frequency excitation of suitable such as about 10kHz, when turning to torque in turning axle 24, the magnetoconductivity being endowed anisotropic magnetostriction portion 81,82 changes, thus, the inductance of coil 85,85,85,85 also changes.
In the example in figure 3, opposed with the first magnetostrictive film 81 and configure two field coils (magnetic test coil) 85,85, opposed with the second magnetostrictive film 82 and configure two field coils (magnetic test coil) 85,85, but these field coils (magnetic test coil) 85,85,85, distribution between the control part 42 shown in 85 and Fig. 1 and electronic circuit illustrate.Connector 92 can be used in the distribution of field coil (magnetic test coil) 85,85,85,85 side to be connected with the distribution of control part 42 side.The distribution of these components be omitted in Fig. 3 and electronic circuit can adopt the structure as shown in Figure 2 of such as Japanese Unexamined Patent Publication 2009-264812 publication.
Also can be out of shape the example of Fig. 3, opposed with the first magnetostrictive film 81 and the second magnetostrictive film 82 and configure the special field coil of an independence, such as can also adopt the structure as shown in Figure 6 of Japanese documentation 1.
Linking part 24i is the axial end portion linked with steering wheel 21 through universal shaft joint 23,23 as shown in Figure 1 and steering axle 22.Linking part 24i is such as made up of the serration for linking universal shaft joint 23.Linking part 24i and turning axle 24 are integrally formed.
Fig. 4 to show near the test section 83 of Fig. 3 magnetic shield 54a, 54b of configuration, Fig. 5 show assembling before magnetic shield 54a, 54b and the stereographic map of sensor housing 55.
In the example of fig. 5, magnetic shield 54a has the first annular portion 54a1.As shown in Figure 4, the first annular portion 54a1 encirclement does not have around the part of turning axle 24 in magnetostriction portion 82, and opposed with the part of the turning axle 24 between magnetostriction portion 82 and linking part 24i.Magnetic shield 54a (the first annular portion 54a1) is such as 0.5 ~ 1mm with the gap of turning axle 24, but is not defined as this scope.First annular portion 54a1 surrounds turning axle 24 and opposed with it, therefore, enters into the external magnetic field noise of the inside of turning axle 24 easily to the first annular portion 54a1 side transfer of magnetic shield 54a from the top (linking part 24i side) of turning axle 24.Consequently, the magnetic flux (the external magnetic field noise towards coil 85) in turning axle 24 reduces.Thereby, it is possible to suppress the reduction of the accuracy of detection of magnetostrictive torque sensor 41.When the magnetoconductivity of magnetic shield 54a (the first annular portion 54a1) is higher than the magnetoconductivity of turning axle 24, magnetic flux easily moves to magnetic shield 54a.
Magnetic shield 54a also has the second annular portion 54a3 opposed with the upper end of sensor housing 55, and the second annular portion 54a3 is connected with the first annular portion 54a1 via the flat-disc portion 54a2 of hollow.The diameter (internal diameter) of the second annular portion 54a3 is larger than the diameter (internal diameter) of the first annular portion 54a1, therefore, the distance between the central shaft CL of the second annular portion 54a3 and turning axle 24 is than the distance between the first annular portion 54a1 and central shaft CL.The magnetic flux transferring to magnetic shield 54a side (the first annular portion 54a1 side) from turning axle 24 side in the second annular portion 54a3 of magnetic shield 54a through time, can make this magnetic flux away from coil 85.
Magnetic shield 54a also has the three annular portion 54a5 opposed with sensor housing 55, and the 3rd annular portion 54a5 is connected with the second annular portion 54a3 via the flat-disc portion 54a4 of hollow.The diameter (internal diameter) of the 3rd annular portion 54a5 is larger than the diameter (internal diameter) of the second annular portion 54a3, therefore, the distance between the 3rd annular portion 54a5 and the central shaft CL of turning axle 24 is than the distance between the second annular portion 54a3 and central shaft CL.In other words, the distance between the part (the 3rd annular portion 54a5) of opposed with coil 85 magnetic shield 54a and central shaft CL is than the first annular portion 54a1 or the distance between the second annular portion 54a3 and central shaft CL.The magnetic flux transferring to magnetic shield 54a side (the first annular portion 54a1 and the second annular portion 54a3 side) from turning axle 24 side in the 3rd annular portion 54a5 of magnetic shield 54 through time, this magnetic flux can be made further away from coil 85.In the example of fig. 5, magnetic shield 54a entirety is unitarily formed by identical material.
Magnetic shield 54b has the 4th cylindrical portion 54b1 and flange 54b2, and the material of magnetic shield 54b can be identical with the material of magnetic shield 54a, also can be different.Magnetic shield 54b (the 4th cylindrical portion 54b1) is opposed with magnetic shield 54a (the 3rd annular portion 54a5), and magnetic flux is from the 3rd annular portion 54a5 side and then to the 4th cylindrical portion 54b1 side transfer.Magnetic shield 54a (the 3rd annular portion 54a5) is such as 0.5 ~ 1mm with the gap of magnetic shield 54b (the 4th cylindrical portion 54b1), but is not defined as this scope.The magnetic flux transferring to the 4th cylindrical portion 54b1 side advances to flange 54b2.Like this, magnetic shield 54a (54a1 ~ 54a5) by the external magnetic field noise that enters from steering wheel 21 side rotary rotating shaft 24 to magnetic shield 54b (54b1,54b2) relaying.
But, because turning axle 24 usually needs mechanical torsion and bending strength, therefore using ferroalloy as mother metal, and also need to heat-treat.Due to this thermal treatment, carbon can be remained in mother metal.The turning axle 24 containing impurity such as carbon like this, compared with the turning axle not containing impurity, is easily subject to the impact of external magnetic field noise.In other words, turning axle 24 is made up of magnetic material.When the first annular portion 54a1 or magnetic shield 54a is not opposed with turning axle 24, alternating flux caused by the alternating magnetic field of engine, generator, motor etc. enters from the top of turning axle 24, in the detection signal carrying out low damage torque sensor 41, produce noise, thus cause the reduction of accuracy of detection.As the replacement of low-pass filter, such noise just can be made to move to magnetic shield 54a side by the first annular portion 54a1.
Magnetic shield 54a can suppress the external magnetic field noise entered from steering wheel 21 side rotary rotating shaft 24.The external magnetic field noise entered to coil 85,85 or test section 83 from other directions also can be suppressed by magnetic shield 54a.Magnetic shield 54a, 54b are made up of magnetic material (comprising amorphous magnetic material), and little preferred of the large and coercive force of magnetoconductivity is such as iron, silicon steel, resist permalloy, ferrite etc.The thickness of magnetic shield 54a, 54b is such as 1mm ~ 10mm.
In the example of fig. 5, magnetic shield 54a such as with magnetostrictive film 82 is carried out to the coil 85 of excitation, 85 corresponding parts have the slit 54as parallel with the central shaft CL of turning axle 24.As mentioned above, the 3rd annular portion 54a5 of magnetic shield 54a surrounds coil 85,85 around, thus can suppress the external magnetic field noise in other directions beyond from the top of turning axle 24.But, simultaneously in the 3rd annular portion 54a5, the magnetic flux produced by coil (field coil) 85,85 reduces because flowing through the vortex flow of magnetic shield 54a (the 3rd annular portion 54a5), consequently, the magnetic flux that can be detected via magnetostrictive film 82 by coil (magnetic test coil) 85,85 is also reduced.Like this, the 3rd annular portion 54a5 makes the detection sensitivity of torque sensor 41 reduce.Therefore, with in coil 85,85 corresponding parts, there is slit 54as according to magnetic shield 54a of the present invention.Can make external magnetic field noise away from coil 85,85 by the part (the 3rd annular portion 54a5) without slit 54as, and the reduction of the detection sensitivity of torque sensor 41 can be suppressed by slit 54as.
In the example of fig. 5, magnetic shield 54b does not have the slit parallel with central shaft CL, but magnetic shield 54b such as also can with magnetostrictive film 81 is carried out to the coil 85 of excitation, 85 corresponding parts have the slit parallel with the central shaft CL of turning axle 24.
Fig. 6 is the enlarged drawing of the variation of magnetic shield 54a, the 54b representing Fig. 3.In the example of fig. 6, the 3rd annular portion 54a5 of magnetic shield 54a can surround four coils, 85,85,85,85 and two magnetostriction portions 81,82 around.In the example of fig. 6, magnetic shield 54a the 3rd annular portion 54a5 with four coils 85,85,85,85 corresponding parts have slit 54as.
The present invention is not limited to above-mentioned illustrative embodiment, and the above-mentioned embodiment exemplified also can easily change by the art personnel in the scope that claims comprise.
Claims (1)
1. a magnetostrictive torque sensor, it possesses:
There is the turning axle in magnetostriction portion;
Described magnetostriction portion is carried out to the field coil of excitation;
To the magnetic test coil that the change of the magnetic characteristic in described magnetostriction portion detects;
At least surround the magnetic shield of the surrounding of described field coil,
The feature of described magnetostrictive torque sensor is,
Described turning axle is made up of magnetic material,
Described magnetic shield also surrounds around the part of the described turning axle without described magnetostriction portion,
Described magnetic shield has the slit parallel with the central shaft of described turning axle in the part corresponding with described field coil,
The part corresponding with the described part of the described turning axle without described magnetostriction portion of an end of described magnetic shield has integrally formed annular portion to replace described slit, distance between the part of the described magnetic shield opposed with described field coil and described central shaft is than the distance between described annular portion and described central shaft, and the other end of described magnetic shield is open end.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011-192943 | 2011-09-05 | ||
| JP2011192943A JP5439446B2 (en) | 2011-09-05 | 2011-09-05 | Magnetostrictive torque sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102980698A CN102980698A (en) | 2013-03-20 |
| CN102980698B true CN102980698B (en) | 2015-09-09 |
Family
ID=47854924
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210286981.1A Active CN102980698B (en) | 2011-09-05 | 2012-08-13 | Magnetostrictive torque sensor |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP5439446B2 (en) |
| CN (1) | CN102980698B (en) |
| BR (1) | BR102012022346A2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6411256B2 (en) * | 2015-03-19 | 2018-10-24 | 本田技研工業株式会社 | Magnetostrictive torque sensor and electric power steering apparatus |
| DE102016209190A1 (en) * | 2016-05-26 | 2017-11-30 | Audi Ag | Cover arrangement for a steering housing |
| CN107628185B (en) * | 2016-07-18 | 2019-12-06 | 行安机电股份有限公司 | Torque force detector |
| JP6661502B2 (en) * | 2016-09-23 | 2020-03-11 | 本田技研工業株式会社 | Magnetostrictive torque sensor and method of manufacturing magnetostrictive torque sensor |
| DE102018131712A1 (en) * | 2018-12-11 | 2020-06-18 | Thyssenkrupp Ag | Magnetic shielding of a torque sensor for an electromechanical power steering system of a motor vehicle |
| CN117330222B (en) * | 2023-12-01 | 2024-01-26 | 常州市昌隆电机股份有限公司 | Woodworking motor axial torque detection device and detection method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1666095A (en) * | 2002-07-03 | 2005-09-07 | 铃木株式会社 | Magnetostrictive torque sensor shaft and method for manufacturin the same |
| CN101750009A (en) * | 2009-12-31 | 2010-06-23 | 南京磁谷科技有限公司 | Magnetic-shielding eddy current sensor probe and method for reducing eddy current effect |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3065230B2 (en) * | 1995-08-01 | 2000-07-17 | 株式会社クボタ | Magnetostrictive torque sensor |
| JP2003042862A (en) * | 2001-07-30 | 2003-02-13 | Suzuki Motor Corp | Magnetostriction type torque sensor |
| JP4516281B2 (en) * | 2003-04-02 | 2010-08-04 | 本田技研工業株式会社 | Torque sensor |
| JP4732473B2 (en) * | 2008-03-03 | 2011-07-27 | 本田技研工業株式会社 | Magnetostrictive torque sensor and vehicle steering apparatus |
| JP4648419B2 (en) * | 2008-03-03 | 2011-03-09 | 本田技研工業株式会社 | Magnetostrictive torque sensor, method of manufacturing magnetostrictive torque sensor, and vehicle steering apparatus |
-
2011
- 2011-09-05 JP JP2011192943A patent/JP5439446B2/en not_active Expired - Fee Related
-
2012
- 2012-08-13 CN CN201210286981.1A patent/CN102980698B/en active Active
- 2012-09-04 BR BR102012022346A patent/BR102012022346A2/en not_active IP Right Cessation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1666095A (en) * | 2002-07-03 | 2005-09-07 | 铃木株式会社 | Magnetostrictive torque sensor shaft and method for manufacturin the same |
| CN101750009A (en) * | 2009-12-31 | 2010-06-23 | 南京磁谷科技有限公司 | Magnetic-shielding eddy current sensor probe and method for reducing eddy current effect |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5439446B2 (en) | 2014-03-12 |
| BR102012022346A2 (en) | 2013-10-29 |
| CN102980698A (en) | 2013-03-20 |
| JP2013053953A (en) | 2013-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102980698B (en) | Magnetostrictive torque sensor | |
| US9970834B2 (en) | Torque sensor and electric power steering system | |
| US20090224500A1 (en) | Device for determining an angle of rotation | |
| EP2947442B1 (en) | Torque sensor and electric power steering system | |
| US6422095B1 (en) | Magnetostrictive torque sensor and electric power steering apparatus including the same | |
| US8047325B2 (en) | Motor vehicle steering system | |
| US7762148B2 (en) | Magnetostrictive torque sensor and electric power steering apparatus | |
| US20090107756A1 (en) | Motor rotation angle detection device | |
| EP2592404A1 (en) | Torque Detection Device and Electric Power Steering System | |
| JP3898610B2 (en) | Torque sensor | |
| EP3671157B1 (en) | Torque sensor and steering device | |
| CN108502012A (en) | Transfer and rotation direction sensor system | |
| JP4801816B2 (en) | Electric power steering device | |
| US8836267B2 (en) | Torque detection device and electric power steering system | |
| JP2015194430A (en) | Vehicle power steering system and manufacturing method of the same | |
| JP2013195361A (en) | Torque sensor | |
| JP2011148494A (en) | Electric power steering device | |
| JP5372583B2 (en) | Magnetostrictive torque sensor and electric power steering device | |
| JP2008233040A (en) | Torque detection device | |
| JP5397672B2 (en) | Electric power steering device | |
| JP2007283893A (en) | Electric steering device | |
| JP4275998B2 (en) | Torque sensor and electric power steering device | |
| JP4833635B2 (en) | Torque sensor and electric power steering device | |
| JP5597607B2 (en) | Magnetostrictive torque sensor | |
| JP4634559B2 (en) | Electric power steering device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |