JP6516589B2 - Rotary contactless power supply transformer and torque detector using the same - Google Patents

Description

  The present invention relates to the improvement of the structure of a transformer for supplying power to circuits placed on a rotating body in order to detect various physical quantities of the rotating body in a machine.

  When detecting various physical quantities of the rotating body, there is a drawback that direct wiring can not be made to a detector or a circuit placed from the fixed side to the rotating body side. In the known method of supplying power to the rotating body, there is a slip ring mechanism, but the slip ring mechanism needs to be subjected to precise processing and assembly in order to maintain good mechanical contact between the brush and the slip ring over a long period of time. The In addition to preventing leakage from the slip ring and the brush, it is necessary to replace and maintain the parts regularly because the brush is worn. Furthermore, since dust is generated at the time of wear, suction and cleaning within the casing are also necessary.

  On the other hand, the rotary type non-contact power supply transformer requires an AC conversion circuit because it uses electromagnetic induction, but no contact failure occurs because it is non-contact, insulation is easy, and maintenance is not necessary. Is advancing.

  In the method of attaching the transformer on the primary side to the outer circumference fixed side of the rotary shaft, in the case where the primary core is structured to cover the rotary shaft, the secondary core and the secondary coil all around. The problem was that the In particular, as the diameter of the rotary shaft increases, the diameter of the secondary core correspondingly increases, and the outer diameter of the primary core also increases, which causes the increase in the size of the apparatus and the increase in manufacturing cost. The

  On the other hand, while using a substantially U-shaped core to wind the coil between the two projections as the primary side, the coil provided on the rotating side bites into the inside of the substantially U-shape. It is known in the art to reduce the size of the apparatus and the manufacturing cost with a structure facing each other. (For example, refer to patent document 1)

JP 2000-58355 A JP, 2013-156230, A

However, in the rotary type non-contact power feeding transformer including the patent document 1, the coil is covered because the opposing points of the primary side and the secondary side are close and the secondary side is rotating. It is difficult, and the open structure is usual. Therefore, when the electric circuit unit that obtains electric power from the rotary contactless power supply transformer and detects the physical quantity is mounted on the rotation side substrate, the electric circuit unit that detects this physical quantity emits from the rotary contactless power supply transformer In some cases, noise may be received, making it difficult to obtain accurate physical quantities. In addition, an electric circuit that transmits the detected physical quantity from the rotating side by radio or the like also receives noise in the same manner, which may cause a malfunction or a missing transmission. Therefore, as disclosed in Patent Document 2, an invention is disclosed in which the rotary type non-contact power feeding transformer and the electrical circuit unit for detecting the physical quantity are separated, but since both are separately arranged, the axial length is large. It has become an obstacle to the miniaturization of the device.

  The present invention has been made to solve the conventional problems as described above, and it is possible to remove noise from an electric circuit unit or the like that detects a physical quantity provided on a rotating body without upsizing the apparatus. An object of the present invention is to provide a rotary contactless power supply transformer that suppresses and supplies power.

The rotary contactless power supply transformer of the present invention is
A primary core made of a magnetic material having a U-shaped cross section with projections provided on both sides,
A primary coil which is wound between the projection of the primary core,
A hollow cylindrical secondary side core having a cylindrical surface concentric with the substantially cylindrical rotation axis rotatably supported and having a cylindrical surface opposite to the tip end surface of the projection of the primary side core at a predetermined distance ;
It is disposed on the outer periphery of the secondary core, sandwiched between the projections arranged in parallel to one plane perpendicular to the axial direction of the rotation shaft, and is wound to be opposed to the primary coil. Secondary coil, and
A rotary type non-contact power supply for supplying power to a strain gauge provided on the rotary shaft and detecting a torque applied to the rotary shaft, and a rotary substrate that digitally converts the torque detected by the strain gauge and transmits the light. A transformer,
The primary core is arranged only in part of the circumferential direction of the rotation axis,
It extends in the axial direction from the primary core, including a region in which at least the primary core and the primary coil are projected onto a plane perpendicular to the axial direction of the rotation shaft from at least one protrusion of the primary core It is characterized in that a primary side core extending portion is provided .

In the rotary type non-contact power feeding transformer of the present invention, it is preferable that the primary side core extension portion includes a region obtained by projecting the secondary side core onto one surface perpendicular to the axial direction.

  In the rotary type non-contact power feeding transformer of the present invention, it is preferable that the primary side core extension part be formed of a conductor.

  In the rotary type non-contact power feeding transformer of the present invention, it is preferable that the primary side core extension part be formed of a magnetic material.

  In the rotary type non-contact power feeding transformer of the present invention, it is preferable that the primary side core extending portion be formed by laminating a magnetic material laminated with a resin film on the primary side core.

  The torque detector of the present invention is characterized by including the above-mentioned rotary type non-contact power supply transformer.

  According to the present invention, by providing the extended portion in the primary side core, it is possible to reduce the diffusion of the noise generated from the rotary type non-contact power supply transformer, and to reduce the influence on the electric circuit on the rotary shaft side. It enables accurate measurement of physical quantities such as torque. In addition, the extension of the primary core covers the side surfaces of the secondary core, so that stable transmission of magnetic flux can be realized, and the efficiency of non-contact power feeding can also be improved.

It is a partial section perspective view of a torque detector which has a rotation type non-contact electric supply transformer concerning an embodiment of the present invention. It is a sectional view showing the composition of the torque detector which has a rotary type non-contact electric supply transformer concerning the embodiment of the present invention. It is B part detail drawing of the rotary type non-contact electric power feeding transformer which concerns on embodiment of this invention. It is AA sectional drawing of the rotary type non-contact electric power feeding transformer which concerns on embodiment of this invention. It is a circuit block diagram of a torque detector which has a rotary type non-contact electric supply transformer concerning an embodiment of the present invention. It is a graph when a torque is measured with the torque detector which has the rotary type non-contact electric power feeding transformer without the conventional primary side core extension part. It is a graph when a torque is measured with the torque detector which has a rotation type non-contact electric power feeding transformer with a primary side core extending | stretching part which concerns on embodiment of this invention.

  Hereinafter, with reference to the attached drawings, a rotary contactless power supply transformer and a torque detector having the same according to an embodiment of the present invention will be described.

FIG. 1 is a partial cross-sectional perspective view showing an inside by cutting an exterior cover or the like which is a part of a torque detector 1 having a rotary type non-contact power feeding transformer 40 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along a plane parallel to the axial direction through the axial center of the torque detector 1.

As shown to FIG. 1, FIG. 2, the torque detector 1 which has the rotary type non-contact electric power feeding transformer 40 which concerns on this embodiment is the structure integrated with the reduction gear connected with the motor (not shown). The present embodiment is an example, and may be directly connected to a drive source such as a motor. The motor shaft 101 serving as an output from the motor side is rotatably supported by the bearing 102, and the power from the motor is transmitted from the motor shaft 101 to the rotating shaft 2 via the wave generator 14 and the flexspline 13. . That is, this reduction gear is a wave gear reduction gear, and it has a thin cup shape, a flexspline 13 provided with gear teeth on the outer periphery of the opening, and an inner peripheral surface corresponding to the outer peripheral gear teeth of the flexspline 13 And a wave generator 14 located on the open inner periphery of the flexspline 13 and connected to the motor shaft 101. The rotary shaft 2 is fastened to the diaphragm portion 13a of the flexspline 13, that is, the reduction gear output portion by a screw.

The rotating shaft 2 has a substantially cylindrical shape, and is rotatably supported via a bearing 3 attached to the shaft cover 15 and a bearing 18 attached to the cover 16. The rotary shaft 2 has a strain-flexing portion 2a having a function of a strain-flexing body, and the strain-flexing portion 2a has strength in the axial direction of the rotary shaft and does not deform, but bends in a twisting direction It is configured to double as a strain generating body and a power transmission shaft. The strain gauge 30 is adhered to the cylindrical surface of the strain generating portion 2 a, and the rotational torque applied to the rotating shaft 2 can be detected. In addition, since the strain gauge 30 is covered with the support member 32 after assembly, in FIG. 1, a part of the support member 32 is cut | disconnected and the strain gauge 30 is displayed. Wiring from the strain gauges 30 is performed by lead wires 31 and is connected to a rotation side substrate 4 described later.

FIG. 3 is an enlarged detailed cross-sectional view enlarging the portion B in FIG. 2, and is indirectly fixed to the cover 16 side, and the primary side of the rotary non-contact power feeding transformer 40 is configured. The fixed-side substrate 10 is fixed to the cover 16 with the insulating sheet 34 interposed therebetween, and the U-shaped magnetic primary core 7 having projections formed at both ends is fixed via the core holder 9 It is attached to the side substrate 10. A primary coil 8 formed by winding a copper wire is provided between the projections of the primary core 7. In the present embodiment, a low loss ferrite material is used for the primary side core 7. The core holder 9 is made of resin or the like and has a shape that encloses the primary core 7 and holds the same.

  On the other hand, the secondary side of the rotary type non-contact power feeding transformer 40 is configured to face the primary side coil 8 and the primary side core 7 at a predetermined interval on the rotary shaft 2. The secondary core 6 is provided concentrically with the rotating shaft 2, and the secondary coil 5 is provided on the outer periphery of the secondary core 6. The secondary side core 6 is provided at a protrusion of the primary side core 7 with a predetermined distance, and in the present embodiment, the secondary side core 6 is thin by laminating sintered ferrite with a resin film. The sheet-like member is bonded to the cylindrical surface of the support member 32 coaxially fixed to the rotary shaft 2 and may be inserted into a hollow cylindrical ferrite. Further, in the secondary side coil 5, a copper wire is wound in a plurality of stages so as to be sandwiched between the both projections of the primary side core 7 in the axial direction, and is fixed with an adhesive.

A primary core extending portion 20 is provided on the left side surface of the protrusion of the primary core 7. The primary core extended portion 20 is formed by laminating sintered ferrite with a resin film to form a sheet, and is adhered and fixed to the side surface of the protrusion of the primary core 7. The primary side core extension portion 20 is provided so as to cover a region in which at least the primary side core 7 and the primary side coil 8 are projected on one plane perpendicular to the axial direction of the rotation shaft 2 and further rotates the secondary side core 6 It is extended and covered to the area | region projected on one surface perpendicular | vertical to the axial direction of the axis | shaft 2 (refer FIG. 3, FIG. 4). Further, the material of the primary side core extension portion 20 may be a metal plate having a conductive effect and having a shielding effect.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2 and drawn while passing through the primary core extended portion 20, and the positional relationship between the primary core 7, the secondary core 6 and the core holder 9 Is shown. Therefore, noise emitted through the gap between the primary core 7 and the secondary core 6 can be particularly reduced by the primary core extended portion 20. Therefore, it is possible to reduce the noise diffusion to the part on the left side of the primary side core extending part 20 in FIGS. 1 and 2. At the same time, the magnetic flux generated from the tip end surface 7b of the primary core 7 to the surface of the secondary core 6 is also covered by the primary core extending portion 20, so that the stability of power feeding is improved. In the present embodiment, although the primary side core extending portion 20 and the primary side core 7 are separately joined by bonding, the primary side core extending portion 20 and the primary side core 7 are integrally formed. It is good.

Further, the rotation side substrate 4 is fixed to the rotation shaft 2 so as to be sandwiched by the support member 32 and the substrate holding ring 33, and the communication element 21 for communicating with the fixed side substrate 10 is mounted on the rotation side substrate 4 ing. Therefore, the support member 32 is a columnar member that connects the portion supporting the secondary core 6 and the portion supporting the rotating substrate 4 and accommodates both of them, and stores the lead wire from the secondary coil 5 in unison. And three pillars (see FIG. 4).

Then, with reference to FIG. 5, the circuit of the torque sensor 1 which has the rotary contactless power supply transformer 40 which concerns on embodiment of this invention, and this is demonstrated. The circuit of the torque detector 1 is composed of a fixed side substrate 10 fixed to the cover 16 and a rotating side substrate 4 fixed to the rotary shaft 2 and rotated together, and provided outside the fixed side substrate 10 Power is supplied from the DC power supply 201.

The direct current voltage supplied from the direct current power source 201 is converted into alternating current by the switching circuit 202 on the fixed side substrate 10, and when the current converted into alternating current is supplied to the primary side coil 8, the alternating current magnetic field becomes the primary side core The alternating current magnetic field is transmitted to the secondary side core 6 on the rotating shaft side to generate a current in the secondary side coil 5. The induced current is rectified by the rectifying circuit 301 in the rotating side substrate 4 and is supplied to the Wheatstone bridge circuit portion formed of the strain gauges 30. The output from the rectifying circuit 301 is also supplied to other circuits in the rotation side substrate 4, that is, the amplification circuit 302, the A / D conversion circuit 303, and the rotation side CPU 304. Power is supplied to the rotating side substrate 4 in a noncontact manner by the above mechanism.

In the actual measurement of torque, when torque is applied to the rotating shaft 2, the strained portion 2a of the rotating shaft 2 is distorted according to the magnitude of the torque, and the magnitude of this distortion is the change of the resistance value of the strain gauge 30. The amplitude signal is output from the Wheatstone bridge circuit, amplified by the amplifier circuit 302, and then digitized by the A / D conversion circuit 303 after being amplified by the amplifier circuit 302.

The amplifier circuit 302 is an analog circuit that amplifies a slight change in resistance of the strain gauge 30, and thus is susceptible to noise. For this reason, if a shield case or the like is provided on the amplification circuit 302 of the rotation side substrate 4, it becomes difficult to design to maintain the rotation balance of the rotation side substrate 4, and the inertia of the entire rotating body including the rotation shaft 2 is It will increase and also cost up. Therefore, on the side of the rotary type non-contact power feeding transformer that is likely to be a noise source, a device that does not emit noise is important, and in the present embodiment, the primary side core extension part 20 plays its role.

Next, signal processing such as modulation is performed by the rotation side CPU 304 for calculation calculation from the magnitude of distortion to torque value and transmission, and light is transmitted from the communication element 21. The communication element 21 may be any of radio waves, infrared rays, visible rays and the like. The communication element 21 is also mounted on the fixed side substrate 10, signal processing such as demodulation is performed by the fixed side CPU 203, and then the torque value digitized by the D / A conversion circuit 204 is converted to a predetermined analog voltage And output at a voltage proportional to the torque value. Of course, the detected torque value may be output from the fixed CPU 203 as a direct digital signal.

FIGS. 6 and 7 show waveforms of torque values obtained by the torque detector 1 when measurement is carried out in a state where a constant load is applied to the actual torque detector 1. FIG. 6 is a view without the conventional primary core extension 20, and FIG. 7 is a view provided with the primary core extension 20 according to the embodiment of the present invention. The horizontal axis is time (seconds), and the vertical axis is a torque value. In FIG. 6, the torque value is disturbed by noise particularly in the vicinity of 1 to 6 seconds. On the other hand, in the case where the primary side core extension portion 20 shown in FIG. 7 is provided, the spike-like waveform disappears, and the variation is generally small, and it can be seen that the influence of noise is reduced.

  In the above, based on the embodiment of the torque detector suitable for application of this invention, it demonstrated. It is understood by those skilled in the art that this embodiment is an exemplification, and various modifications can be made to each component, and such modifications are also within the scope of the present invention.

  The rotary type non-contact power feeding transformer according to the present invention can be used for an apparatus for detecting a physical quantity of a rotating body such as a torque detector.

DESCRIPTION OF SYMBOLS 1 Torque detector 2 Rotating shaft 2a Strain generation part 3 Bearing 4 Rotation side board 5 Secondary side coil 6 Secondary side core 7 Primary side core 7b Protrusion tip surface 8 Primary side coil 9 Core holder 10 Fixed side board 12 Circular Spline 13 Flexspline 13a Diaphragm portion 14 Wave generator 15 Shaft cover 16 Cover 18 Bearing 20 Primary core extension 21 Communication element 30 Strain gauge 31 Lead wire 32 Support member 33 Substrate holding ring 34 Insulating sheet 40 Rotational non-contact power supply transformation Unit 101 Motor shaft 102 Bearing 201 DC power supply 202 Switching circuit 203 Fixed side CPU
204 D / A conversion circuit 301 Rectification circuit 302 amplification circuit 303 A / D conversion circuit 304 rotation side CPU

Claims (6)

A primary core made of a magnetic material having a U-shaped cross section with projections provided on both sides,
A primary coil which is wound between the projection of the primary core,
A hollow cylindrical secondary side core having a cylindrical surface concentric with a substantially cylindrical rotary shaft rotatably supported and facing a front end surface of the projection of the primary side core at a predetermined distance ;
It is disposed on the outer periphery of the secondary core between the projections arranged in parallel to one plane perpendicular to the axial direction of the rotary shaft, and is opposed to the primary coil. With a wound secondary coil,
A rotary type that is provided on the rotary shaft and detects a torque applied to the rotary shaft, and a rotary substrate that digitally converts the torque detected by the strain gauge and transmits the light. Contactless power supply transformer,
The primary core is disposed only in a part of the circumferential direction of the rotation axis,
From at least one of said protruding portion of said primary core, include regions projected onto a surface perpendicular to at least the primary core and the primary coil in the axial direction, primary stretched in the axial direction Side core extension is provided,
A rotary contactless power supply transformer characterized by The rotary type non-contact power supply transformer according to claim 1, wherein the primary side core extension portion includes a region in which the secondary side core is projected on one surface perpendicular to the axial direction.   The rotary type noncontact power feeding transformer according to any one of claims 1 to 2, wherein the primary side core extension part is formed of a conductor.   The rotary type non-contact power supply transformer according to any one of claims 1 to 2, wherein the primary side core extension portion is formed of a magnetic material.   The rotary type non-contact power feeding transformer according to claim 4, wherein the primary side core extending portion is formed by laminating a magnetic material laminated with a resin film on the primary side core. . A torque detector comprising the rotary contactless power supply transformer according to any one of claims 1 to 5.