JP2019184466A - Torque measuring device - Google Patents

Abstract

To provide a torque measuring device which can increase the accuracy of measuring a torque by reducing the influence of temperatures on a strain gauge.SOLUTION: There is provided a torque measuring device which acts on a drive plate 2 connected to a crank shaft at the center part of the drive plate and connected to a torque converter at the outer periphery part of the drive plate. The torque measuring device includes: strain gauges 11 (A to F) arranged in a strain gauge 8 of the drive plate 2; and temperature gauges 12 (A to F) for compensating for the change of the resistance values of the strain gauges 11 (A to F) by temperatures, the strain gauges 11 (A to F) and the temperature gauges 12 (A to F) being arranged on the same circle of the drive plate 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a torque measuring device.

  In recent years, in order to evaluate the performance of automobile transmissions, it is required that the engine torque can be measured with high accuracy in a state where the engine and the transmission are connected. As a conventional technique for this torque measurement, there is known one using a drive plate interposed between an engine crankshaft and a transmission torque converter as a torque meter (see, for example, Patent Documents 1 to 3). These patent documents describe the use of a strain gauge as a torque detection element.

JP 2005-84000 A Japanese Patent No. 3669421 Japanese Patent No. 6263556

  Since the drive plate is disposed in the engine room, it is exposed to a high temperature environment. When the temperature of the drive plate becomes high, the resistance value of the strain gauge changes, and there is a possibility that accurate torque measurement cannot be performed.

  The present invention is for solving such a problem, and an object of the present invention is to reduce the influence of temperature on a strain gauge and improve the accuracy of torque measurement.

  In order to solve the above problems, the present invention is a measuring device for torque acting on a disk rotating body in which one of a central portion and an outer peripheral portion is connected to an input side rotating body and the other is connected to an output side rotating body, A strain gauge disposed in the strain-generating portion of the disk rotor, and a temperature gauge that compensates for a change in resistance value of the strain gauge due to temperature, and the strain gauge and the temperature gauge rotate the disk. The torque measuring device is arranged on the same circumference of the body.

  According to the present invention, the strain gauge and the temperature gauge are arranged on the same circumferential line of the disc rotating body, so that when the temperature distribution of the disc rotating body has a radial temperature gradient, the strain gauge and the temperature gauge. Can be arranged at an equivalent temperature to each other. Thereby, since the compensation accuracy of the temperature gauge can be increased, the influence of temperature on the strain gauge can be reduced and the torque measurement accuracy can be improved.

  Further, the present invention is characterized in that a compensation conducting wire for compensating for an error in resistance value of the strain gauge is arranged on the same circumferential line.

  According to the present invention, since the temperature of the compensation lead wire that compensates for the error in the minute resistance value of the strain gauge becomes substantially the same as the temperature of the strain gauge, the error in the equilibrium state of the bridge circuit can be reduced.

  Further, the present invention is characterized in that a plurality of lightening holes are formed in the disc rotating body, and the strain gauge, the temperature gauge, and the lightening holes are arranged rotationally symmetrically.

  According to the present invention, it is possible to reduce the variation in the influence of the hollow holes on the strain gauge and the temperature gauge, and to improve the torque detection accuracy of the strain gauge and the compensation accuracy of the temperature gauge.

  Further, the present invention is characterized in that a thermal barrier coating agent is applied to the disk rotating body.

  According to the present invention, the influence of heat transfer and heat radiation can be suppressed, and heat transfer in the disk rotor can be mainly made only for heat conduction. Therefore, a radial temperature gradient appears clearly in the disc rotating body, and the compensation accuracy by arranging the temperature gauge and the compensating conductor on the same circumferential line with respect to the strain gauge can be further enhanced.

  Further, the present invention is characterized in that a heat conductive sheet is stuck between the strain gauge and the temperature gauge.

  According to the present invention, since the strain gauge and the temperature gauge can be made closer to the equivalent temperature, the compensation accuracy of the temperature gauge can be further increased.

  According to the present invention, the influence of temperature on the strain gauge can be reduced, and the torque measurement accuracy can be improved.

It is a front view of the drive plate provided with the torque measuring device of the present invention. It is II-II sectional drawing in FIG. FIG. 3 is an enlarged view of III in FIG. 2. FIG. 2 is an enlarged view around a strain gauge in FIG. 1. It is the basic block diagram of the bridge circuit of a strain gauge, and the block circuit diagram of a transmitter and a receiver. It is a temperature distribution figure of a drive plate by heat conduction simulation. It is a connection circuit diagram of a bridge circuit of a strain gauge, a temperature gauge, and a compensation lead wire.

  In FIG. 1, a torque measuring device 1 according to the present invention is a device that measures torque acting on a drive plate 2. As shown in FIG. 2, the drive plate 2 is a disc rotating body interposed between an engine crankshaft 21 as an input side rotating body and a torque converter 22 as an output side rotating body. As shown in FIG. 1, a plurality of (eight in the present embodiment) first bolt through holes 3 are formed around the center of the drive plate 2 around the axis O, and a plurality ( Six second bolt through holes 4 are formed in this embodiment. As shown in FIG. 2, the drive plate 2 is fastened by a first bolt 23 having a central portion on one surface abutted against the end surface of the crankshaft 21 and passing through the first bolt through hole 3, and on the other surface side. The outer peripheral portion is abutted against the torque converter 22 and is fastened by the second bolt 24 that has passed through the second bolt through hole 4.

  As shown in FIG. 1, a ring gear 5 that meshes with a pinion gear of a cell motor (not shown) is formed on the outer peripheral edge of the drive plate 2. In the center of the drive plate 2, a centering hole 6 that is fitted to the crankshaft 21 to center the drive plate 2 is formed. Further, near the outer peripheral portion of the drive plate 2, a plurality of lightening holes 7 are formed at equal intervals in the circumferential direction. As described above, in the present embodiment, the six second bolt through holes 4 are formed, and the total of the six lightening holes 7 are located between the adjacent second bolt through holes 4. Is formed.

  The drive plate 2 is formed with a strain generating portion 8 for positively generating strain when a rotational force is transmitted from the center portion on the input side to the outer peripheral portion on the output side. Six strain-generating portions 8 are formed at equal intervals in the circumferential direction, and each strain-generating portion 8 is disposed between adjacent hollow holes 7. The strain generating portion 8 includes a pair of slits 9 formed across a radial line L that passes through the center between adjacent thinning holes 7, a rectangular thin portion 10 formed between the pair of slits 9, and It is configured with. The slit 9 is formed so as to extend along the radial line L, and is formed as a long hole penetrating the front and back of the drive plate 2. As can be seen from FIG. 3, the thin-walled portion 10 is formed in a thin-wall shape so that a recess is provided on each of the front and back surfaces of the drive plate 2.

"Strain gauge 11"
In FIG. 1, strain gauges 11 (shown as 11 </ b> A to 11 </ b> F in FIG. 1) are attached to the front and back of each thin portion 10. In other words, a total of twelve strain gauges 11 arranged at equal intervals on the same circumferential line on the one surface side and the other surface side are attached to the drive plate 2 by an adhesive or the like. The strain gauge 11 is disposed so that the center portion thereof is positioned on the radial line L. In FIG. 1, six strain gauges 11A, 11B,..., 11F on one side are arranged in order, and strain gauges 11G, 11H,.

  The strain gauge 11 functions as a resistance element, and expands and contracts by an external tensile force or compressive force to change its resistance value. The bridge circuit 31 shown in FIG. 5 generates a voltage between the points A and B by the change in the resistance values of the resistance elements R1 to R4. Thereby, the said voltage can be taken out as an output voltage according to a torque. When no distortion occurs, the bridge circuit 31 is in an equilibrium state with “R1 · R4 = R2 · R3”, and the output voltage becomes zero. The output voltage is transmitted via a transmitter 35 including an amplifier 32, an A / D converter 33, and a CPU 34, for example. The transmitter 35 is attached to a predetermined portion of the drive plate 2. The transmitted signal is received by a receiver 39 including a CPU 36, a D / A converter 37, and an amplifier 38, and a torque measurement value is displayed and stored by a torque output device 40. Each strain gauge 11 is configured to include two resistance elements.

"Temperature gauge 12, compensating lead wire 13"
In FIG. 1, a torque measuring device 1 includes a temperature gauge 12 (indicated by 12A to 12F in FIG. 1) that compensates for changes in the resistance value of the strain gauge 11 due to temperature, and compensation that compensates for errors in the resistance value of the strain gauge 11. Conductive wire 13 is provided. The temperature gauge 12 includes a resistance element that correlates with temperature. As shown in FIG. 5, the temperature gauge 12 having a specification matched to the temperature resistance coefficient of the strain gauge 11 is connected in series to the bridge circuit 31, so that the resistance value of the strain gauge 11 when the temperature changes can be obtained. It is possible to compensate for the change so that the same voltage is output for the same distortion.

  The compensating conductor 13 is a resistance element that compensates for an error between the resistance elements of the strain gauge 11, and has a temperature coefficient of electric resistance that is substantially the same as that of the strain gauge 11. As shown in FIG. 5, the compensating conductor 13 is connected in series to one side of the bridge circuit 31, and the compensating conductor 13 is equivalent to the temperature of the strain gauge 11 as will be described later. Error can be reduced.

  Here, if there is a temperature difference between the temperature gauge 12, the compensation lead wire 13, and the strain gauge 11, the compensation accuracy is shifted due to the temperature difference, and the strain gauge 11 cannot be compensated correctly. Therefore, in order to increase the compensation accuracy, it is necessary to arrange the temperature gauge 12 and the compensation lead wire 13 at a temperature substantially equivalent to the temperature of the strain gauge 11.

  The inventor paid attention to the temperature distribution based on the usage environment of the drive plate 2 and analyzed it as follows. Since the drive plate 2 is disposed in the engine room, it is exposed to a high temperature environment. There are three types of heat transfer methods: heat conduction, heat transfer, and heat radiation. However, for heat transfer and heat radiation transmitted from the ambient temperature in the engine room, extreme bias does not occur in the distribution of ambient temperature. Therefore, it can be considered that heat is transmitted substantially uniformly throughout the drive plate 2. Further, for example, by applying a thermal barrier coating agent to the surface of the drive plate 2, the influence of heat transfer and heat radiation can be suppressed. Therefore, the temperature distribution of the drive plate 2 is dominated by the influence of heat conduction from the crankshaft 21 and the torque converter 22.

  Usually, the crankshaft 21 and the torque converter 22 of the engine have a higher temperature of the crankshaft 21. Therefore, due to the temperature difference between the crankshaft 21 and the torque converter 22, the drive plate 2 conducts heat radially outward from the central portion that is the connecting portion with the crankshaft 21. That is, the temperature distribution of the drive plate 2 becomes a low temperature as the distance from the axis O is increased, and a radial temperature gradient distribution having a uniform temperature over the entire circumference on an arbitrary circumferential line.

  FIG. 6 shows a temperature distribution of the drive plate 2 by a heat conduction simulation. It can be seen from FIG. 6 that a high temperature region 41, a medium high temperature region 42, a medium temperature region 43, and a low temperature region 44 are distributed radially from the center. About the middle temperature region 43 where the lightening holes 7 exist, due to the effect of heat radiation from the lightening holes 7, it extends substantially linearly between the adjacent lightening holes 7 without strictly following the circumferential direction, The overall temperature distribution is hexagonal. However, if the number of the hollow holes 7 is about 6 or more, the polygonal shape is almost a perfect circle. Therefore, the temperature distribution in the intermediate temperature region 43 is also circular, ignoring a slight temperature difference. It can be considered uniform in the circumferential direction.

  From the above, the strain gauge 11, the temperature gauge 12, and the compensating lead wire 13 are arranged at equal distances from the axis O, that is, the strain gauge 11, the temperature gauge 12, and the compensating lead wire 13 are arranged at the same circumference of the drive plate 2. By arranging on the line, each person can be placed under a substantially equivalent temperature, and the compensation accuracy of the temperature gauge 12 and the compensating lead wire 13 can be increased.

  In FIG. 1, in the present embodiment, a total of twelve temperature gauges 12 are attached to one side of the drive plate 2 and the other side by an adhesive or the like beside one slit 9 of each strain generating portion 8. It has been. Temperature gauges 12A to 12F are arranged next to the strain gauges 11A to 11F on the one surface side, and temperature gauges 12G to 12L (FIG. 7) are arranged next to the strain gauges 11G to 11L on the other surface side. In FIG. 4, the symbol P <b> 1 indicates the center point of the outer side of the strain gauge 11, and the symbol P <b> 2 indicates the center point of the inner side of the strain gauge 11. Symbol C1 is a circumferential line passing through the central point P1, and symbol C2 is a circumferential line passing through the central point P2. In the present invention, “the strain gauge 11 and the temperature gauge 12 are arranged on the same circumferential line” means that at least a part of the temperature gauge 12 is in a range between the circumferential line C1 and the circumferential line C2. Means a relationship that is located. In order to increase the compensation accuracy, it is preferable to arrange the temperature gauge 12 so that more than half, preferably 80% or more, of the area of the temperature gauge 12 covers the range between the circumferential line C1 and the circumferential line C2.

  The same applies to the compensation lead wire 13. In the present invention, “the compensation lead wire 13 is disposed on the same circumferential line” means that at least a part of the compensation lead wire 13 includes the circumferential line C 1 and the circumferential line C 2. Means a relationship located in the range between.

  In addition, in the present embodiment, the strain gauge 11 is a range between the outer tangent line S1 and the inner tangent line S2 when the outer tangent line that contacts the adjacent hollow holes 7 is the outer tangent line S1 and the inner tangent line is the inner tangent line S2. Is located. Strictly speaking, the temperature distribution between the outer tangent line S1 and the inner tangent line S2 is not a radial shape centered on the axis O, and is based on the simulation result of FIG. It is inferred that the temperature gradient gradually becomes lower in the radial direction along the orthogonal line. Accordingly, when a straight line that is orthogonal to the radial line L1 and passes through the center point P1 is S3, and a straight line that is orthogonal to the radial line L1 and passes through the center point P2 is S4, at least a part of the temperature gauge 12 is the straight line S3. If it arrange | positions in the range between straight lines S4, the compensation precision at the time of arrange | positioning the strain gauge 11 between the lightening holes 7 can be improved more. In order to further increase the compensation accuracy, it is preferable to arrange the temperature gauge 12 so that more than half of the area of the temperature gauge 12, desirably 80% or more, falls within the range between the straight line S 3 and the straight line S 4. In this embodiment, it arrange | positions so that the substantially whole temperature gauge 12 may be located in the range between the straight line S3 and the straight line S4. A part of the compensation lead wire 13 may also be arranged in a range between the straight line S3 and the straight line S4.

  As shown in FIG. 1, the wiring 14 from the strain gauge 11, the temperature gauge 12, and the compensating lead wire 13 constitutes a bridge circuit 31 and is routed around the circumference, and then the transmitter 35 (FIG. (See FIG. 5). FIG. 7 shows a specific example of the bridge circuit 31 used in this embodiment. Reference numerals 11A1 and 11A2 denote resistances of the strain gauge 11A shown in FIG. 1, and 11B1, 11B2,... 11L1, and 11L2 denote resistances of the strain gauges 11B to 11L, respectively.

  11G1, 11A1, 11K1, 11E1, 11I1, 11C1, compensating conductors 13, 11L2, 11F2, 11J2, 11D2, 11H2, and 11B2 are connected in series to one branch path of the bridge circuit 31. 11G2, 11A2, 11K2, 11E2, 11I2, 11C2, 11B1, 11H1, 11D1, 11J1, 11F1, and 11L1 are connected in series to the other branch path. The voltage between the point A between the 11C1 and the compensation lead wire 13 and the point B between the 11C2-11B1 is output as a voltage corresponding to the torque. Temperature gauges 12G, 12A, 12H, 12B, 12I, and 12C are connected in series between the positive power supply voltage Vcc and the bridge circuit 31, and the temperature gauges 12D, 12J, 12E, and 12K are connected between the bridge circuit 31 and the ground GND. , 12F, 12L are connected in series. The above connection example is merely an example, and the design may be appropriately changed by routing the wiring 14 or the like.

  As described above, the strain gauge 11 disposed in the strain generating portion 8 of the drive plate 2 and the temperature gauge 12 that compensates for a change in the resistance value of the strain gauge 11 due to temperature are provided. Are arranged on the same circumference of the drive plate 2, the compensation accuracy of the temperature gauge 12 can be enhanced by utilizing the temperature distribution unique to the drive plate having a radial temperature gradient. Thereby, for example, the rotational torque of the engine can be measured with high accuracy with an error of about 0.1% or less with respect to the rating.

  If the compensating lead wire 13 that compensates for an error in the resistance value of the strain gauge 11 is arranged on the same circumferential line as the strain gauge 11, the temperature of the compensating lead wire 13 becomes substantially the same as the temperature of the strain gauge 11, so that the bridge circuit The error in the equilibrium state can be reduced.

  As in the present embodiment, if the drive plate 2 is formed with a plurality of lightening holes 7 and the strain gauge 11, the temperature gauge 12, and the lightening holes 7 are arranged rotationally symmetrically about the axis O, the strain gauge 11 In addition, the variation in the influence of the hole 7 on the temperature gauge 12 can be reduced, and the torque detection accuracy of the strain gauge 11 and the compensation accuracy of the temperature gauge 12 can be increased. Furthermore, the rotational balance of the drive plate 2 can be maintained.

  If a thermal barrier coating agent is applied to the drive plate 2, the heat transfer by the atmosphere and the influence of heat radiation can be suppressed, and the heat transfer in the drive plate 2 can be mainly limited to heat conduction. Therefore, a radial temperature gradient appears clearly in the drive plate 2, and the compensation accuracy by disposing the temperature gauge 12 and the compensation conductor 13 on the same circumferential line with respect to the strain gauge 11 can be further enhanced.

  The preferred embodiment of the present invention has been described above. If a heat conductive sheet is attached between the strain gauge 11 and the temperature gauge 12, the strain gauge 11 and the temperature gauge 12 can be brought closer to the equivalent temperature, so that the compensation accuracy of the temperature gauge 12 can be further increased. it can.

  The shape example of the strain generating portion 8 is not limited to the slit 9 or the thin portion 10 as long as the strain is generated.

1 Torque measurement device 2 Drive plate (rotary disk)
3 First Bolt Passing Hole 4 Second Bolt Passing Hole 7 Thickening Hole 8 Strain Part 9 Slit 10 Thin Part 11 Strain Gauge 12 Temperature Gauge 13 Compensating Lead 21 Crankshaft (Input Side Rotating Body)
22 Torque converter (output side rotating body)

Claims (6)

A torque measuring device acting on a disk rotating body in which one of a central part and an outer peripheral part is connected to an input side rotating body and the other is connected to an output side rotating body,
A strain gauge disposed in the strain-generating portion of the disk rotor,
A temperature gauge that compensates for changes in the resistance value of the strain gauge due to temperature; and
And the strain gauge and the temperature gauge are arranged on the same circumferential line of the disc rotating body.   The torque measuring device according to claim 1, wherein a compensating lead wire that compensates for an error in resistance value of the strain gauge is disposed on the same circumferential line. The disk rotor is formed with a plurality of lightening holes,
The torque measuring device according to claim 1, wherein the strain gauge, the temperature gauge, and the lightening hole are arranged rotationally symmetrically.   The torque measuring device according to any one of claims 1 to 3, wherein a thermal barrier coating agent is applied to the disk rotating body.   The torque measuring device according to any one of claims 1 to 4, wherein a heat conductive sheet is adhered between the strain gauge and the temperature gauge.   The disc rotating body is a drive plate in which a crankshaft of an engine as the input side rotating body is connected to the central portion, and a torque converter as the output side rotating body is connected to the outer peripheral portion. The torque measuring device according to any one of claims 1 to 5.

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