JP6886336B2 - Shaft torque transducer - Google Patents

Description

The present invention relates to a shaft type torque converter used for torque measurement of automobile parts inspection equipment, generators, motors, and the like.

Conventionally, shaft type torque converters used for torque measurement of automobile parts inspection equipment, generators or motors have been known (see, for example, Patent Document 1). The configuration of the shaft type torque converter described in Patent Document 1 includes a detection circuit that processes an electric signal from a strain gauge and transmits it as a detection signal by infrared communication, and a detection circuit provided on a substrate fixed to a housing. It is equipped with an output circuit that receives the detection signal from and outputs it to the outside.

Japanese Unexamined Patent Publication No. 2014-098718

When performing torque measurement using a shaft type torque converter as described in Patent Document 1, the rotating shaft may be rotated at a very high speed of, for example, 25,000 rpm. In this case, the rotating shaft and the rotating shaft fixing portion (stator) are firmly fixed to each other by bearings, and the constantly fluctuating torque signal detected by the rotating shaft is continuously, that is, always continuous and accurate. A non-contact signal transmission structure for transmitting to the rotating shaft fixing portion is required.
Along with this, in the case of a shaft type torque converter, a strain gauge for torque detection and various electronic components and electricity for amplifying a slight output signal obtained from this strain gauge and constantly transmitting it to the rotation fixing part. It is necessary to place the components near the axis of rotation.
When measuring the torque of a generator or motor, the torque changes rapidly in a short time, so if the transmission of the output signal is interrupted even for a short time, the output signal of this part cannot be obtained on the fixed side. , It becomes extremely difficult to predict and calculate this missing output signal. Estimating this output signal for a part of the output signal that could not be transmitted does not match the actual torque characteristic value.

Further, in the shaft type torque converter described in Patent Document 1, the above-mentioned electronic parts and electric parts are arranged on a disk-shaped substrate provided on the rotating shaft, and the shaft-type torque converter rotates at a high speed as described above. No mention is made of a configuration in which the output signal from the strain gauge provided on the rotating shaft is constantly and continuously transmitted to the rotating fixed portion.

An object of the present invention is to provide a shaft type torque converter capable of continuously and accurately measuring the torque acting on a rotating shaft rotating at high speed, that is, continuously and accurately.

The shaft type torque transducer according to the first embodiment of the present invention is
Rotation axis and
Torque detector and
A support plate attached to the rotating shaft and rotating integrally with the rotating shaft,
It is a shaft type torque converter equipped with
The torque detector
A torque detection element that detects the torque acting on the rotating shaft, and
A light source that outputs the torque value obtained from the torque detection element as an optical signal, and
A ring-shaped light guide that guides the output light from the light source,
A light receiving unit that receives light emitted from the light guide unit and a light receiving unit that receives light.
With
The light source and the light guide portion are attached to the support plate, and the light source and the light guide portion are attached to the support plate.
The light source is arranged inside the light guide portion and is arranged.
The output light from the light source is transmitted radially outward from the outer peripheral surface of the light guide portion by propagating in the light guide portion.

The shaft type torque transducer according to the second embodiment of the present invention is
Rotation axis and
Torque detector and
A support plate attached to the rotating shaft and rotating integrally with the rotating shaft,
It is a shaft type torque converter equipped with
The torque detector
A torque detection element that detects the torque acting on the rotating shaft, and
A light source that outputs the torque value obtained from the torque detection element as an optical signal, and
A ring-shaped light guide that guides the output light from the light source,
A light receiving unit that receives light emitted from the light guide unit and a light receiving unit that receives light.
With
The light source is attached to the support plate and
The light guide portion is attached to the rotating shaft, has an inner peripheral surface and an outer peripheral surface, and is provided with a conical trapezoidal cavity inside the inner peripheral surface.
The light source is arranged outside the light guide portion and is arranged.
The first portion of the output light from the light source is reflected by the inner peripheral surface, and the second portion of the output light from the light source is transmitted in the light guide portion. Light is emitted from the outer peripheral surface of the light guide portion to the outside in the radial direction.

A reflector provided on the surface of the light guide portion on the side opposite to the support plate side is further provided.
Is preferable.

A plurality of the light sources are arranged at equal intervals in the circumferential direction of the support plate.
Is preferable.

A component of a rotation side control circuit for controlling the light source is arranged on the support plate.
Is preferable.

It is a partial cross-sectional view of the shaft type torque converter which concerns on 1st Embodiment of this invention. It is a partially enlarged view of the shaft type torque converter which concerns on 1st Embodiment of this invention. It is a perspective view of the shaft type torque converter which concerns on 1st Embodiment of this invention. It is a circuit diagram of the shaft type torque converter which concerns on 1st Embodiment of this invention. It is a partially enlarged view of the modification of the shaft type torque converter which concerns on 1st Embodiment of this invention. It is a partial cross-sectional view of the shaft type torque converter which concerns on 2nd Embodiment of this invention. It is a partially enlarged view of the shaft type torque converter which concerns on 2nd Embodiment of this invention. It is a partially enlarged view of the modification of the shaft type torque converter which concerns on 2nd Embodiment of this invention.

FIG. 1 is a partial cross-sectional view of the shaft type torque converter according to the first embodiment of the present invention, FIG. 2 (a) is a partially enlarged perspective view thereof, and FIG. 2 (b) is a partially enlarged perspective view thereof. It is a side view, FIG. 2C is a sectional view taken along the line AA of FIG. 2B, and FIG. 3 is a perspective view thereof.
In FIG. 1, the electrical connection relationship of each component is not shown.

The shaft type torque converter 1 includes a rotary shaft 100, a shaft support unit 200, a torque detection unit 300, a support plate 400, a housing 500, an electromagnetic coil 600, and a circuit board 700, and includes a rotary shaft 100. Converts the torque acting on the output signal.
In the following description, the rotating side is a general term for rotating parts such as the rotating shaft 100, the torque detection unit 300, and the support plate 400, and the fixed side is the shaft support portion 200, the housing 500, the circuit board 700, and the like. The fixed part of is generically called.

Torque acts on the rotating shaft 100 when an inspection facility, a generator, a motor, or the like for an automobile part, which is an object to be measured, is operated. A torque detection shaft portion 122 having an outer diameter dimension smaller than that of the rotary shaft 100 is partially formed on the rotary shaft 100, and a torque detection element 310 described later is attached to the torque detection shaft portion 122.
The rotating shaft 100 is made of, for example, metal.

The shaft support portion 200 includes a bearing 210 and rotatably supports the rotary shaft 100.

The torque detection unit 300 outputs the torque detection element 310 that detects the torque acting on the rotating shaft 100, the light source 320 that outputs the torque value obtained from the torque detection element 310 as an optical signal α, and the output light from the light source 320. It includes a ring-shaped light guide unit 330 that guides light, and a light receiving unit 350 that receives light emitted from the light guide unit 330.

The torque detection element 310 is arranged in the circumferential direction of the torque detection shaft portion 122 formed on the rotation shaft 100. The torque detection element 310 is a Wheatstone bridge circuit composed of a strain gauge, and although the detailed configuration is not shown here, the strain gauge includes a flexible sheet made of, for example, a polyimide resin, and the strain gauge. A strain gauge element formed by folding multiple narrow copper foil patterns on a sheet in a ninety-nine fold shape with a narrow interval from each other, and the same direction as the extending direction of each element from both ends of the strain gauge element. It has a pattern extending portion extending to the surface and a rectangular solder tab formed by connecting to each pattern extending portion.

The light source 320 is attached to the support plate 400 and is arranged inside the ring-shaped light guide portion 330. The light source 320 comprises at least one light emitting element such as an LED or a laser. The light source 320 outputs an optical signal α according to the output of the torque detection element 310.

The light guide unit 330 is a ring-shaped member that is attached to the support plate 400 and has an inner peripheral surface 330i that serves as a light incident surface and a light reflecting surface, and an outer peripheral surface 330o that serves as a light emitting surface. That is, the light guide unit 330 is provided with a cylindrical cavity inside the inner peripheral surface 330i, and the light source 320 is arranged in this cavity.
Of the output light from the light source 320, the light that is vertically incident on the inner peripheral surface 330i is emitted from the outer peripheral surface 330o as it is. On the other hand, of the output light from the light source 320, the light that is inclined and incident on the inner peripheral surface 330i has its optical path changed inside the light guide unit 330, and is repeatedly reflected by the inner peripheral surface 330i and the outer peripheral surface 330o. , Exits from the outer peripheral surface 330o.
Grooves and dots are formed in at least a part of the inner peripheral surface 330i, and a light reflecting surface for reflecting light is formed. Therefore, the light incident on the inside of the light guide portion 330 is these. The light path is changed by the grooves and dots, and the light is emitted from the outer peripheral surface 330o by being reflected by the light reflecting surface.
As described above, the output light from the light source 320 is transmitted in the light guide unit 330 and is irradiated outward in the radial direction with a uniform illuminance in the circumferential direction from the entire outer peripheral surface 330o. This irradiation light is received by the light receiving unit 350 on the fixed side provided so as to face the light guide unit 330. That is, the light guide unit 330 transmits the light signal α from the light source 320 to the light receiving unit 350 in a non-contact manner.
From the viewpoint of light transmission efficiency, the light source 320 and the light guide unit 330 are in contact with each other, and the width of the light source 320 (the length in the direction of the rotation axis 100) and the thickness of the light guide unit 330 are the same. It is preferable to have. Although not shown, it is preferable that a reflector is provided on the surface of the light guide unit 330 opposite to the support plate 400 side. Further, it is more preferable that the reflector is arranged so as to cover both the light source 320 and the light guide unit 330 because the light leaked to the light source 320 side can be effectively used.
The light guide unit 330 is made of a resin such as polycarbonate.

The light receiving unit 350 is attached to the circuit board 700 on the fixed side. The light receiving unit 350 is composed of a light receiving element such as a photodiode or a phototransistor. The light receiving unit 350 receives the light signal α from the light source 320 and converts it into an electric signal.

The support plate 400 has a predetermined thickness and diameter, and is made of a so-called PCB, which is a printed circuit board formed in a disk shape. The support plate 400 is attached to the rotating shaft 100 and rotates integrally with the rotating shaft 100.
The surface of the support plate 400 on the light guide portion 330 side is white, and it is preferable that the support plate 400 functions as a reflector.
It is preferable that most of the components (resistors, capacitors, etc.) of the rotation side control circuit 450, which will be described later, are evenly arranged on the support plate 400. In the illustrated example, the rotation side control circuit 450 is arranged as a part of the support plate 400 for simplification of description, but in reality, the components of the rotation side control circuit 450 are around the central axis of the rotation axis 100. It is preferable that they are arranged evenly in a well-balanced manner, that is, over the entire support plate 400. This is preferable because the support plate 400 does not shake when the rotating shaft 100 rotates at high speed.
Alternatively, a dummy weight or the like may be arranged on the support plate 400 to balance the gravity between the weight and the components of the rotation side control circuit 450. In this case, the components of the rotating side control circuit 450 need not be evenly arranged.
Further, a circuit pattern (not shown) is formed on the support plate 400, and the rotation side control circuit 450 and the light source 320 are electrically connected to each other.

The housing 500 has a function of forming a closed space in combination with the shaft support portion 200 at both side portions 501a and 501b so as to prevent ambient light existing outside from entering the inside, particularly the light receiving portion 350. Regarding the shape of the housing 500, in FIG. 3, an example is shown in which the upper portion 502 is cylindrical and the bottom portion 503 is flat plate-shaped, but the bottom portion 503 may also be cylindrical and the entire housing 500 may be cylindrical. Then, the upper portion 502 may be formed into a flat plate shape, and the entire housing 500 may be formed into a rectangular parallelepiped shape.
The housing 500 is made of, for example, metal.

The electromagnetic coil 600 includes a fixed side coil 602 and a rotating side coil 603 arranged so as to face each other. The fixed coil 602 is fixed between the top 502 and the bottom 503 of the housing 500, and the rotating coil 603 is fixed to the rotating shaft 100. In combination with the fixed side coil 602 and the rotating side coil 603, electric power is supplied from the fixed side to the rotating side by electromagnetic induction.

The circuit board 700 is arranged in the housing 500, and the light receiving unit 350 and the fixed side detection circuit 750 are attached. The fixed-side detection circuit 750 is electrically connected by a lead wire 750a to a connector 750b located outside the upper portion 502 of the housing 500. The connector 750b inputs and outputs signals to and from the outside.

FIG. 4 is a circuit diagram of the shaft type torque converter of the present invention. The shaft type torque converter 1 further includes a rotation side control circuit 450 for controlling the light source 320, and a fixed side detection circuit 750 for detecting an electric signal from the light receiving unit 350.

The rotating side control circuit 450 includes a smoothing circuit 404, a regulated power supply circuit 405, a strain gauge power supply circuit 406, a Wheatstone bridge circuit 407, an amplifier 408, a filter circuit 409, a voltage / frequency converter 410, and the like.

The fixed side detection circuit 750 includes a power supply 701, an oscillation circuit 702, an amplifier 703, an AGC circuit 704, a waveform shaping circuit 705, a frequency / voltage conversion circuit 706, a low-pass filter circuit 707, an output buffer circuit 708, an output terminal 709, and the like. There is.

The output of the power supply 701 is supplied to the oscillation circuit 702, and an AC voltage having a frequency of, for example, about 15 to 20 kHz is applied to the fixed coil 602 via the amplifier 703.
Electric power is supplied from the fixed coil 602 to the rotating coil 603 by electromagnetic induction.

The smoothing circuit 404 rectifies and smoothes the AC voltage induced in the rotating coil 603, and supplies a DC voltage having a small ripple voltage to the regulated power supply circuit 405. The regulated power supply circuit 405 supplies a voltage with minimal fluctuation to the strain gauge power supply circuit 406. The strain gauge power supply circuit 406 supplies the required voltage to the Wheatstone bridge circuit 407. The Wheatstone bridge circuit 407 is composed of a strain gauge of the torque detection element 310.
The output of the Wheatstone bridge circuit 407 is amplified by the amplifier 408, and after the noise of the excess frequency component is removed by the filter circuit 409, it is supplied to the voltage / frequency converter (V / F conversion) 410.
The voltage / frequency converter (V / F conversion) 410 converts the magnitude of the voltage into high and low frequencies. By frequency modulation, the non-linear influence of the light source 320 and the light receiving unit 350 can be removed.

The light signal α emitted by the light source 320 is received by the light receiving unit 350. The amplitude fluctuation of the electric signal output from the light receiving unit 350 is adjusted by the AGC circuit (Automatic Gain Control Circuit) 704, and the amplitude is amplified to the logic level. The amplified signal is supplied to the frequency / voltage conversion circuit (F / V conversion) 706 via the waveform shaping circuit 705. After the frequency fluctuation is converted into the voltage fluctuation by the frequency / voltage conversion circuit (F / V conversion) 706, the unnecessary noise component is removed by the low-pass filter circuit 707.
The low-pass filter circuit 707 uses, for example, a known secondary or tertiary Butterworth filter or the like. Then, the low-pass filter circuit 707 is connected to the output buffer circuit 708, and the measured value of the torque is supplied to the output terminal 709.

In the above, an example in which the output signal from the Wheatstone bridge circuit is frequency-modulated and transmitted as analog is shown, but it may be converted into a digital signal by A / D conversion, and if necessary, further modulated and transmitted. In that case, the signal received on the fixed side may be output as a digital signal or may be output as an analog signal by D / A conversion.

As described above, in the shaft type torque converter 1 according to the first embodiment of the present invention, the torque information of the rotating shaft 100 detected by the torque detecting element 310 is converted into an optical signal α from the light source 320. The optical signal α is uniformly irradiated outward in the radial direction via the light guide unit 330, and is received by the light receiving unit 350. As a result, during the rotation of the rotating shaft 100, the light signal α from the light source 320 can be transmitted to the light receiving unit 350 without interruption, and the torque acting on the rotating shaft 100 rotating at high speed is interrupted, that is, constantly and continuously. And it can be measured accurately.

FIG. 5A is a partially enlarged perspective view of a modified example of the shaft type torque converter according to the first embodiment of the present invention, and FIG. 5B is a partially enlarged side view thereof.
The shaft type torque converter of the modified example is the same as the shaft type torque converter 1 described above except that it has three light sources 320. The three light sources 320 are arranged at an angle of 120 degrees to each other. This configuration is preferable because the uniformity of the light emitted outward in the radial direction is improved and the support plate 400 is not shaken when the rotating shaft 100 rotates at high speed.

FIG. 6 is a partial cross-sectional view of the shaft type torque converter according to the second embodiment of the present invention, FIG. 7 (a) is a partially enlarged perspective view thereof, and FIG. 7 (b) is a partially enlarged perspective view thereof. It is a cross-sectional view.
The shaft type torque converter 2 according to the second embodiment is the same as the shaft type torque converter 1 described above except for the light source 320 and the light guide unit 340.

The light source 320 is attached to the support plate 400 and is arranged outside the light guide portion 340. Further, the three light sources 320 are arranged at an angle of 120 degrees to each other.

The light guide unit 340 is a ring-shaped member attached to the rotating shaft 100 and having an inner peripheral surface 340i serving as a light reflecting surface and an outer peripheral surface 340o serving as a light emitting surface. The light guide portion 340 is provided with a conical trapezoidal cavity inside the inner peripheral surface 340i, and the inner peripheral surface 340i is inclined with respect to the outer peripheral surface 340o. A reflector 345 is provided on the surface of the light guide portion 340 opposite to the support plate 400 side. Since the reflector 345 is arranged so as to cover the light guide portion 340, it is possible to prevent leakage of the optical signal from the light source 320.
Of the output light from the light source 320, the first portion perpendicular to the first side surface 340a (broken line arrow in FIG. 7B) is incident from the first side surface 340a and reflected by the inner peripheral surface 340i. It emits from the outer peripheral surface 330o. Of the output light from the light source 320, the second portion inclined with respect to the first side surface 340a is incident from the first side surface 340a, the optical path is changed inside the light guide portion 330, and the first side surface is changed. The reflection is repeated on the 340a and the second side surface 340b, and the light is emitted from the outer peripheral surface 340o.
As described above, the output light from the light source 320 is transmitted to the inside of the light guide unit 340 so as to be irradiated outward in the radial direction with a uniform illuminance in the circumferential direction from the entire outer peripheral surface 330o. This irradiation light is received by the light receiving unit 350 on the fixed side provided so as to face the light guide unit 330. That is, the light guide unit 340 transmits the light signal α from the light source 320 to the light receiving unit 350 in a non-contact manner.
In the illustrated example, three light sources 320 are provided, but the number of light sources 320 may be one or more. However, it is preferable that the plurality of light sources 320 are arranged at equal intervals in the circumferential direction of the support plate 400.

FIG. 8 is a partially enlarged view of a modified example of the shaft type torque converter according to the second embodiment of the present invention.
In the modified example, a connection portion between the light guide portion 340 and the rotating shaft 100 is provided on the right side of the conical trapezoidal cavity of the light guide portion 340, and the light guide portion 340 is securely attached to the rotating shaft 100. The reflector 345 may not be provided.

The shapes, dimensions, materials, and the like of each component described in each of the above-described embodiments are merely examples, and can be appropriately changed within the range in which the effects of the present invention can be exhibited.

1 Shaft type torque converter 2 Shaft type torque converter 100 Rotating shaft 122 Torque detection Shaft part 200 Shaft support part 210 Bearing 300 Torque detection part 310 Torque detection element 320 Light source 330 Light guide part 340 Light guide part 345 Reflector 350 Light receiving part 400 Support plate 450 Rotating side control circuit 500 Housing 502 Top 503 Bottom 600 Electromagnetic coil 602 Fixed side coil 603 Rotating side coil 700 Circuit board 750 Fixed side detection circuit

Claims (4)

Rotation axis and
Torque detector and
A support plate attached to the rotating shaft and rotating integrally with the rotating shaft,
It is a shaft type torque converter equipped with
The torque detector
A torque detection element that detects the torque acting on the rotating shaft, and
A light source that outputs the torque value obtained from the torque detection element as an optical signal, and
A ring-shaped light guide that guides the output light from the light source,
A light receiving unit that receives light emitted from the light guide unit and a light receiving unit that receives light.
With
The light source is attached to the support plate and
The light guide portion is attached to the rotating shaft, has an inner peripheral surface and an outer peripheral surface, and is provided with a conical trapezoidal cavity inside the inner peripheral surface.
The light source is arranged outside the light guide portion in the axial direction.
The first portion of the output light from the light source is reflected by the inner peripheral surface, and the second portion of the output light from the light source is transmitted in the light guide portion. Light is emitted from the outer peripheral surface of the light guide to the outside in the radial direction.
Shaft torque transducer. A reflector provided on the surface of the light guide portion on the side opposite to the support plate side is further provided.
The shaft type torque transducer according to claim 1. A plurality of the light sources are arranged at equal intervals in the circumferential direction of the support plate.
The shaft type torque transducer according to claim 1 or 2. A component of a rotation side control circuit for controlling the light source is arranged on the support plate.
The shaft type torque transducer according to any one of claims 1 to 3.

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