GB2093992A - Torque measurement apparatus - Google Patents
Torque measurement apparatus Download PDFInfo
- Publication number
- GB2093992A GB2093992A GB8205606A GB8205606A GB2093992A GB 2093992 A GB2093992 A GB 2093992A GB 8205606 A GB8205606 A GB 8205606A GB 8205606 A GB8205606 A GB 8205606A GB 2093992 A GB2093992 A GB 2093992A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- component
- pulse
- torque
- shaft
- 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.)
- Withdrawn
Links
- 238000005259 measurement Methods 0.000 title claims description 5
- 239000011159 matrix material Substances 0.000 claims abstract description 22
- 238000006073 displacement reaction Methods 0.000 claims abstract description 4
- 239000013307 optical fiber Substances 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 6
- 230000001960 triggered effect Effects 0.000 abstract description 3
- 230000005540 biological transmission Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/12—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving photoelectric means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
Apparatus for measuring torque transmitted by a rotary component such as a shaft (11) during rotation thereof, includes a primary light pulse source (18) which is triggered at a reference position in each revolution of the component to direct a light pulse (21) at a light reflective means (12) disposed on the component at a position subject to displacement by torque transmitted by the component. The light pulse is reflected in a direction or position significant of the transmitted torque onto a suitably positioned photo-diode matrix (23). After calibration of the apparatus the output from the photo-diode matrix is indicative of transmitted torque. In other embodiments using plane mirrors (Figures 6 and 7), the mirror extends radially of the shaft and is disposed at 45 DEG to the axial plane, and in the axial plane, respectively. <IMAGE>
Description
SPECIFICATION
Torque measurement apparatus
This invention relates to apparatus for measuring torque, and is particularly concerned with apparatus for measuring in dynamic components.
The use of an electrical strain gauge bridge for
measuring the torque transmitted by a rotating
component such as a shaft is well known.
However, a problem arises in the transfer of
electrical power to the strain gauge bridge, which
is mounted on a shaft, and in takeoff of the bridge
output.
An optical torquemeter employing a light beam to sense torsional shear strain in a rotating shaft
has been proposed, one such torquemeter
comprising two disc members mounted
concentrically on a shaft for rotation therewith.
Each disc has a plurality of apertures so that it
acts as a rotating light shutter to a beam of light
directed parallel to the axis of rotation of the
shaft. The discs are mounted with their apertures
in alignment in a 'no torque' condition and pulses
of light from a light source mounted near to the
shaft on one side of the discs are received by a
light sensing device positioned at the other side of
the discs as aligned apertures pass the light
source. When the shaft is rotating and transmitting torque, the torsional shear strain in the shaft causes angular movement of the discs
relative to each other by an amount which is
proportional to the torsional shear strain. This
modulates the pulses of light received by the light
sensing device which is generally a photo-electric device that converts the light pulses into a series
of electrical pulses.Whilst the electrical pulses
will vary with both torque and speed, the
mark/space ratio at any given shutter aperture
remains constant, irrespective of rotational speed,
and varies only with aperture changes, i.e. with torque, so that the average electrical signal which
can be presented by meter or other means is,
after calibration, a measure of torque being
transmitted by the shaft.
One difficulty with this arrangement is that of
positioning the light source and the light sensitive
device close to the shaft so that they are in
alignment with each other in a direction parallel
to the axis of rotation of the shaft. A disadvantage
of the arrangement is that of pickup of local noise
interference, such as static produced by shaft
rotation, by the signal output wiring leading from
the photo-electric device. Unless the output
wiring can be adequately screened then it may be
necessary to accommodate signal processing
equipment close to the shaft.
According to the present invention, there is
provided apparatus for measuring torque
transmitted by a rotary component during rotation
thereof, comprising a primary light pulse source
and means for triggering said source at a
reference position in each revolution of the
component to direct a light pulse at a light
reflective means disposed on said component at a position subject to displacement by torque transmitted by the component and so that the pulse is reflected by said reflective means in a direction significant of the transmitted torque, and a photo-diode matrix positioned for receiving pulses of reflected light from said light reflective means.
The rotary component may comprise a torsion element in the form of a shaft adapted at its ends for connection between two rotary components in a dynamic system such as a transmission system.
Alternatively, the rotary component may comprise a suitable rotary member, for example, a transmission shaft, forming part of the dynamic system.
The light reflective means may comprise a mirror or other suitable reflective surface mounted on a circumferential surface of the rotary component.
The triggering means may be of any suitable form and may be mechanical but are preferably optical. For instance, the triggering means may comprise a shutter obturating the transmission path of a continuous primary light source so that momentary opening of the shutter causes transmission of a light pulse along the path.
In a preferred embodiment of the invention the triggering means comprises a secondary light source and two optical fibres each having one of its ends adapted for location adjacent to a reflective area provided over a short arcuate length of a circumferential surface of the component, one of said optical fibres being adapted for receiving light from said secondary light source such as, for example, a C.W. laser or a high power L.E.D., and arranged to direct a light beam onto the rotary path of the reflective area.
When the reflective area passes through the light beam a pulse of reflected light is received by the other optical fibre, and is transmitted to photoelectric means which converts the light pulse into an electrical signal for triggering the primary source to direct a pulse of light onto the light reflective means.
The primary source may comprise a pulsed laser and light from this laser may be transmitted towards the light reflective means by an optical fibre.
In one form of the invention a light pulse from the primary source is directed onto the light reflective means along a path that lies in a plane parallel to and passing through the rotational axis of the component. In this form of the invention the light reflective means may be arranged to reflect the light pulse onto a photo-diode matrix located at a position beyond the light reflective means along the length of the rotary component or, alternatively, the light reflective means may be arranged to reflect the beam of light onto a photodiode matrix located to one side of the light reflective means and the rotary component.
In another form of the invention a beam of light from the source of light is directed onto the light reflective means from one side of the rotary component and is reflected back onto a photo diode matrix located at that side of the rotary component.
The invention will now be further described by way of example, and with reference to the accompanying drawings, in which:
Figure 1 is a pictorial illustration of apparatus for measuring torque transmitted by a rotary component in accordance with one embodiment
of the invention;
Figure 2 is a side elevation on light reflective
means mounted on the component;
Figure 3 is a view looking in plan on light
reflective means mounted on the component;
Figure 4 is a section through line X-X in
Figure 2 with the component in a no-torque condition;
Figure 5 is a similar section to that shown in
Figure 4, but with the component transmitting torque;
Figure 6 is a view looking in plan on apparatus for measuring torque transmitted by a rotary component in accordance with another embodiment of the invention; and
Figure 7 is a view looking on the end of a rotary component and showing apparatus for measuring torque transmitted by the component in accordance with a further embodiment of the invention.
Referring to Figures 1 to 5 of the
accompanying drawings, a rotary component
comprising a shaft 11 of circular cross-section
has light reflective means mounted thereon
comprised by a mirror 12 which is wedge shaped
in length as seen in Figure 2 and convex when viewed in transverse cross-section as seen in
Figures 4 and 5. A reflective area 13 is provided over a short arcuate length of the circumferential surface of the shaft 11 at a position which is
aligned with and spaced from the mirror 12 along the rotational axis of the shaft. The reflective area
13 may be formed in any suitable manner, such
as by bonding a piece of reflective material to the
surface of the shaft, or by highly polishing the
surface of the shaft over this area and suitably dulling the surrounding area of the shaft.The reflective area 13 forms part of a triggering means which is further comprised by a secondary light source, in this embodiment a C.W. laser 14, located remote from the shaft 11 and supplying laser light to one end of an optical fibre 15. The other end of the optical fibre 1 5 is positioned adjacent the reflective area 1 3 so as to project a beam of light onto the rotary path of the reflective area 13.A second optical fibre 1 6 has one end located adjacent the reflective area 13, so that it receives reflected light from the reflective area 1 3. The
reflected light is transmitted through the optical fibre 1 6 to a photo-electric device 1 7 that
converts it into an electrical signal, which is used to cause a primary light pulse source, in this
embodiment a pulsed laser 18, to fire a pulse of
laser light along an optical fibre 1 9. That end of the optical fibre 19 which is remote from the laser
18 is disposed near to the shaft 7 and is
positioned so as to direct an incident beam 21 of laser light along a path lying in a plane parallel to and passing through the rotational axis of the shaft 11 onto the convex surface of the mirror 12.
A beam of reflected light 22 from the mirror 12 is directed onto the face of a photo-diode matrix 23 suitably mounted near to the shaft 11.
In operation of the apparatus, with the shaft 11 rotating, a continuous beam of light from the laser 14 is directed onto the shaft 11 in the rotary path of the reflective area 13. As the reflective area 1 3 passes through the light beam, light is reflected to the optical fibre 16, and transmitted to the photoelectric device 1 7 where it is converted into an electrical signal which is used to cause the laser 18 to fire a pulse of light along the optical fibre 19. This pulse of light leaves the end of the optical fibre 19 as an incident light beam 21 which travels along a path lying in a plane parallel to and passing through the axis of rotation to strike the convex surface of the mirror 1 2 and a reflected light beam 22 is directed onto the photo-diode matrix 23.When the shaft 11 is rotating with no torsional loading the incident beam 21 is reflected in the same plane, and the reflected beam 22 strikes the photo-diode matrix 23 at a central position, as shown in Figure 4, this central position being a datum position giving an output that indicates zero torque.When the shaft 11 is transmitting torque, as shown in Figure 5, the shaft twists under the effect of torsional loading so that the mirror 12 is moved out of alignment with the reflective area 13 by an angle 6. Thus, when the reflective area 1 3 cuts the light beam from the optical fibre 1 5 to cause the laser 1 8 to fire, the incident beam 21 from the optical fibre 1 9 is reflected by the mirror 12 in a direction significant of the transmitted torque so that the
reflected beam 22 strikes the photo-diode matrix
23 at a position which gives a different output from the datum position output.Using known mathematical calibration techniques the apparatus
is calibrated so that outputs from the photo-diode
matrix are indicative of the torque transmitted by the shaft.
It will be noted in the embodiment of Figures 1
to 5 that if the shaft rotates in one direction only,
then only one half of the face of the photo-diode
matrix is used. However, this arrangement is most
useful in cases where the shaft rotates in both
directions, and it is required to measure the
torque being transmitted when the shaft is
rotating in either direction.
In a second embodiment of the invention, shown in Figure 6, apparatus for measuring the torque transmitted by a rotating shaft 11 comprises triggering means (not shown in detail but being similar to that previously described with reference to the embodiment of Figures 1 to 5) for causing a pulsed laser (not shown) to fire a pulse of light along an optical fibre 31. An incident light beam 32 leaving the end of the optical fibre 31 remote from the pulsed laser travels along a path in a plane parallel to and passing through the rotational axis of the shaft 11, and is incident upon a mirror face 33 mounted on the shaft 11 so
as to be angled across the path of the beam 32.
Conveniently the mirror face 33 is mounted so that the angle of incidence of the incident light
beam 32 is fortyfive degrees whereby the
reflected light beam 34 will be at ninety degrees to the incident light beam 32 and will strike a
photo-diode matrix 35 mounted at one side of the
shaft 11. When the shaft 11 is transmitting
torque the torsional strain in the shaft causes
displacement of the mirror surface 33, with
respect to its alignment with the reflective area
13 of the triggering means, to a position shown in dashed line in Figure 6, and the beam of reflected
light 34 is that shown in dashed line striking the photo-diode matrix 35 at a position displaced from the position at which the reflected light beam strikes the matrix when the shaft is not transmitting torque.As in the previous embodiment, using known methematical calibration techniques, the apparatus is calibrated so that the output from the photo-diode matrix 3 is indicative of the torque being transmitted by the shaft.
In the embodiment of Figure 7, a flat mirror face 41 is mounted on the circumferential surface of the shaft 11 so as to lie in a plane parallel to and passing through the rotational axis of the shaft. The triggering means (not shown) is the same as that previously described for the embodiment of Figures 1 to 5, but in this embodiment an optical fibre 42 carrying light from a pulsed laser (not shown) triggered to fire by the triggering means, is mounted at one side ol the shaft 11 so as to direct a beam of incident light 43 onto the flat mirror face 41. A reflected light beam 44 from the flat mirror face 41 is directed onto the face of a photo-diode matrix 45, which is suitably positioned at one side of the shaft 11.When the shaft 11 is rotating in a zero torque condition, the pulsed laser is triggered to fire when the flat mirror face 41 is in the position shown in solid line in Figure 7, and the reflected light beam 44 shown in solid line will fall upon the face of the photo-diode matrix at a position towards one of its edges, where the output from the matrix will be indicative of zero torque. When the shaft is transmitting torque, the torsional loading causes the shaft to twist so that the flat mirror face lags the reflective area of the triggering means, and the pulsed laser is caused to fire when the flat mirror face 41 is in the position shown in broken line in Figure 7. Thus the angle of incidence of the incident beam 43 on the flat mirror face 41 will change, and the angle of reflection of the reflected beam 44 will likewise change so that the reflected beam will strike the photo-diode matrix 45 at a position displaced from the zero torque datum position.
Claims (13)
1. Apparatus for measuring torque transmitted by a rotary component during rotation thereof, comprising a primary light pulse source and means for triggering said primary source at a reference position in each revolution of the component to direct a light pulse at a light reflective means disposed on said component at a position subject to displacement by torque transmitted by the component and so that the pulse is reflected by said reflective means in a direction significant of the transmitted torque, and a photo-diode matrix adapted to be positioned to receive pulses of reflected light from said light reflective means.
2. Apparatus as claimed in Claim 1, wherein the component comprises a torsion element adapted at its ends for connection between two rotary components in a dynamic system.
3. Apparatus as claimed in Claim 1 or Claim 2, wherein the light reflective means comprises a mirror adapted for mounting on a circumferential surface of the component.
4. Apparatus as claimed in any one of the preceding claims, wherein the triggering means comprises a secondary light source and two optical fibres each having one of its ends adapted for location adjacent to a reflective area provided over a short arcuate length of a circumferential surface of the component, one of said optical fibres being adapted for receiving light from said secondary source and arranged to direct a light beam onto the rotary path of said reflective area whereby, in operation, when said reflective area passes through the light beam a pulse of reflected light is received by said other optical fibre and transmitted to photo-electric means which converts the light pulse into an electrical signal for triggering the primary source to direct a light pulse onto the light reflective means.
5. Apparatus as claimed in any preceding claim, wherein said primary source comprises a pulsed laser.
6. Apparatus as claimed in Claim 5, wherein light from the pulsed laser is transmitted towards the light reflective means by an optical fibre.
7. Apparatus as claimed in any preceding claim, wherein said primary source is adapted to direct a pulse of light onto the light reflective means along a path lying in a plane parallel to and passing through the axis of rotation.
8. Apparatus as claimed in any one of Claims 1 to 6, wherein the primary source is adapted to direct a pulse of light onto the light reflective means along a path lying in a plane which is normal to the axis of rotation.
9. Apparatus as claimed Claim 7 or Claim 8, wherein the light reflective means is adapted to reflect an incident light pulse through substantially a right angle onto a suitably positioned photo-diode matrix.
10. Torque measurement apparatus substantially as hereinbefore described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.
11. Torque measurement apparatus substantially as hereinbefore described with reference to and as shown in Figure 6 of the accompanying drawings.
12. Torque measurement apparatus substantially as hereinbefore described with reference to and as shown in Figure 7 of the accompanying drawings.
13. Every novel feature and every novel combination of features described herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8205606A GB2093992A (en) | 1981-02-26 | 1982-02-25 | Torque measurement apparatus |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8106142 | 1981-02-26 | ||
| GB8205606A GB2093992A (en) | 1981-02-26 | 1982-02-25 | Torque measurement apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2093992A true GB2093992A (en) | 1982-09-08 |
Family
ID=26278572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8205606A Withdrawn GB2093992A (en) | 1981-02-26 | 1982-02-25 | Torque measurement apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2093992A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5038616A (en) * | 1989-11-02 | 1991-08-13 | S & S Technologies | Non-intrusive determination of time varying and steady state torsional load magnitudes and locations of a shaft or system of shafts |
| WO1996002815A1 (en) * | 1994-07-20 | 1996-02-01 | Ebi Guenter | Method of measuring torsional stresses and/or axial stresses on a rotating shaft or on a comparable workpiece |
| WO1999022211A1 (en) * | 1997-10-23 | 1999-05-06 | Siemens Aktiengesellschaft | Torque measurement using concentrating reflectors on the rotating shaft |
| CN115014606A (en) * | 2022-05-26 | 2022-09-06 | 天津大学 | Fiber bragg grating dynamic torque measuring device and method based on off-axis interconnector |
-
1982
- 1982-02-25 GB GB8205606A patent/GB2093992A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5038616A (en) * | 1989-11-02 | 1991-08-13 | S & S Technologies | Non-intrusive determination of time varying and steady state torsional load magnitudes and locations of a shaft or system of shafts |
| WO1996002815A1 (en) * | 1994-07-20 | 1996-02-01 | Ebi Guenter | Method of measuring torsional stresses and/or axial stresses on a rotating shaft or on a comparable workpiece |
| US5747699A (en) * | 1994-07-20 | 1998-05-05 | Ebi; Guenter | Method of measuring torsional stresses and/or axial stresses on a rotating shaft or on a comparable workpiece |
| WO1999022211A1 (en) * | 1997-10-23 | 1999-05-06 | Siemens Aktiengesellschaft | Torque measurement using concentrating reflectors on the rotating shaft |
| DE19848068C2 (en) * | 1997-10-23 | 2001-02-08 | Siemens Ag | Device for torque measurement on rotating rotating shafts |
| US6318187B1 (en) | 1997-10-23 | 2001-11-20 | Siemens Aktiengesellschaft | Apparatus for torque measurement on rotating torque shafts |
| CN115014606A (en) * | 2022-05-26 | 2022-09-06 | 天津大学 | Fiber bragg grating dynamic torque measuring device and method based on off-axis interconnector |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |