JP2019219169A - Torque measurement device - Google Patents

Abstract

To realize a torque measurement device capable of stably measuring torque in a wide range from a state where a rotating shaft is stopped to a state where the rotating shaft is rotating at high speed.SOLUTION: A rotating shaft 2 has a magnetostrictive effect portion whose magnetic permeability changes in accordance with torque to be transmitted, and a magnetostrictive sensor 5 is arranged close to the magnetostrictive effect portion. A pair of encoders 3a and 3b in which the characteristics of each detection surface alternately change in the circumferential direction is supported on the rotating shaft 2, and detection portions of a pair of magnetic sensors 4a and 4b are brought close to the detection surfaces of the pair of encoders 3a and 3b. A computing portion 6 obtains the torque transmitted by the rotating shaft 2 by a first function on the basis of an output signal of the magnetostrictive sensor 5, and calculates the torque transmitted by the rotating shaft 2 by a second function on the basis of the phase difference between output signals of the pair of magnetic sensors 4a and 4b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a torque measuring device that is incorporated in, for example, an automatic transmission for an automobile, transmits torque, and is used to measure the magnitude of the transmitted torque.

  In recent years, in order to improve the efficiency and fuel efficiency of automobiles, measure the magnitude of the engine output torque in order to perform optimal output control of the engine (including output control synchronized with the motor in hybrid vehicles). Is required. As a method of measuring the magnitude of the output torque of the engine, for example, it is conceivable to measure the magnitude of the torque transmitted by any of the rotating shafts located downstream of the engine.

  On the other hand, as a method of measuring the torque transmitted by the rotating shaft, a pulse phase difference measurement method and a magnetostriction measurement method are conventionally known.

  As described in, for example, JP-A-63-82330, a pair of encoders are fixed at two positions separated in the axial direction of a rotating shaft, and a method of measuring a pulse phase difference method is described in JP-A-63-82330. The detection unit of the magnetic sensor faces the surface to be detected. The characteristics of the detected surface of the encoder change alternately and at a constant pitch in the circumferential direction. Therefore, the output signals of the pair of magnetic sensors change periodically as the pair of encoders rotate with the rotation axis. Further, when a torque is applied to the rotating shaft and elastic torsional deformation occurs in the rotating shaft, the phase difference between the output signals of the pair of magnetic sensors changes. Since this phase difference takes a value corresponding to the torque (the amount of elastic torsional deformation of the rotating shaft), the torque transmitted by the rotating shaft can be obtained using this relationship.

  As described in, for example, JP-A-59-61730, a magnetostrictive measuring method includes providing a magnetostrictive material on the outer peripheral surface of a rotating shaft and detecting a change in the magnetic permeability of the magnetostrictive material in the vicinity of the magnetostrictive material. A magnetostrictive sensor to perform the measurement. When torque is applied to the rotating shaft and elastic torsional deformation occurs in the magnetostrictive material, a change in magnetic permeability occurs in the magnetostrictive material based on the inverse magnetostrictive effect. Thus, the output signal of the magnetostrictive sensor changes in accordance with the change in the magnetic permeability of the magnetostrictive material, so that the torque transmitted by the rotating shaft can be obtained.

JP-A-63-82330 JP-A-59-61730

When a pulse phase difference type measurement method is used to determine the torque transmitted by the rotating shaft, the condition that the rotating speed of the rotating shaft is 0 min ^-1 (rpm), in other words, the condition that the rotating shaft is stopped Below, since no pulse is generated in the output signal of the magnetic sensor, the torque applied to the rotating shaft cannot be measured. Further, since the torque measurement frequency is limited to the pulse generation frequency, it becomes difficult to measure the torque with high accuracy when the rotation speed of the rotating shaft is low.

  On the other hand, when a magnetostrictive measuring method is used to determine the torque transmitted by the rotating shaft, the output signal of the magnetostrictive sensor is output through a lock-in amplifier circuit. Inside, a low-pass filter is provided. For this reason, in the magnetostrictive measuring method, the response is likely to be reduced, and the output signal is likely to be delayed in time.

  The present invention has been made in view of the above circumstances, and has been developed to realize a structure of a torque measuring device capable of stably measuring torque in a wide range from a state where a rotating shaft is stopped to a state where a rotating shaft is rotating at high speed. It was done.

The torque measuring device of the present invention includes a rotating shaft, a magnetostrictive sensor, a pair of encoders, a pair of magnetic sensors, and a calculator.
The rotating shaft transmits a torque during use, and has a magnetostrictive effect portion whose magnetic permeability changes according to the transmitted torque.
The magnetostrictive sensor is supported on a portion that does not rotate during use in a state where the magnetostrictive sensor is disposed close to the magnetostrictive effect portion, and passes through its own detecting portion and responds to a magnetic flux that changes according to the magnetic permeability of the magnetostrictive effect portion. To change the output signal.
The pair of encoders are supported directly or via another member on the rotation shaft, and alternately change the characteristics of each detected surface in the circumferential direction.
The pair of magnetic sensors is supported by a portion that does not rotate during use, and a detection unit is opposed to each detection surface of the encoder.
The computing unit has a first function of obtaining a torque transmitted by the rotating shaft based on an output signal of the magnetostrictive sensor, and a transmitting function of the rotating shaft based on a phase difference between output signals of the pair of magnetic sensors. It has a second function of determining the torque to be applied.

  In the present invention, the arithmetic unit selects one of the value obtained by the first function and the value obtained by the second function according to the rotation speed of the rotation shaft, and selects the rotation shaft. May be the value of the torque transmitted.

In the present invention, while the rotation speed of the rotating shaft is between 0 min ^-1 and a predetermined value N or less, the computing unit sets a value obtained by the first function as a value of torque transmitted by the rotating shaft, When the rotation speed of the rotating shaft is higher than the predetermined value N, the value obtained by the second function may be used as the value of the torque transmitted by the rotating shaft.

In the present invention, when the rotation speed of the rotating shaft is within a predetermined speed range, the value obtained by the first function and the value obtained by the second function are used as the third function. By using both of them, a function of obtaining the torque transmitted by the rotating shaft can be provided.
In this case, in the speed range (low speed range, extremely low speed range) in which the rotation speed of the torque transmission shaft is from 0 min ^-1 to the predetermined value N1, the arithmetic unit calculates the value obtained by the first function, In a speed range (medium speed range) in which the rotation speed of the rotation shaft is from the predetermined value N1 to the predetermined value N2, the value obtained by the third function is the value of the torque transmitted by the rotation shaft. In a speed range (high-speed range) in which the rotation speed of the rotating shaft is greater than the predetermined value N2, the value obtained by the second function is used as a value of the torque transmitted by the rotating shaft. It can be a value.

In the present invention, the torque transmitted by the rotating shaft is obtained by calculating the third function as an arithmetic average (arithmetic average) of a value obtained by the first function and a value obtained by the second function. The value of
Alternatively, the third function is a weighted average value obtained by weighting the value obtained by the first function and the value obtained by the second function in accordance with the rotation speed of the rotation axis, respectively. May be the value of the torque transmitted.
In this case, the value obtained by the first function is weighted more heavily as the rotation speed of the rotary shaft is smaller, and the value obtained by the second function is weighted heavier as the rotation speed of the rotary shaft is larger. be able to.

  According to the torque measuring device of the present invention, torque can be stably measured in a wide range from a state where the rotating shaft is stopped to a state where the rotating shaft is rotating at high speed.

FIG. 1 is a cross-sectional view illustrating a torque measuring device according to a first example of the embodiment. FIG. 2 is a diagram illustrating a relationship between a rotation speed and a method of calculating a torque adopted by a calculator in the first example of the embodiment. FIG. 3 is a view similar to FIG. 2 and relates to a second example of the embodiment. FIG. 4 is a view similar to FIG. 2 and relates to a third example of the embodiment. FIG. 5 is a schematic diagram showing a fourth example of the embodiment and showing a relationship between a geometric mean value and an arithmetic mean value (weighted mean value) calculated by a computing unit and an actual measured value of torque. FIG. 6 is a sectional view showing a part of a torque measuring device according to a fifth example of the embodiment.

[First Example of Embodiment]
A first example of the embodiment will be described with reference to FIGS. The torque measuring device 1 of this example includes a rotating shaft 2, a pair of encoders 3a and 3b, a pair of magnetic sensors (Hall sensors, MR sensors) 4a and 4b, one magnetostrictive sensor 5, and an arithmetic unit. 6 is provided.

  The rotating shaft 2 has a hollow cylindrical shape as a whole, and has a constant inner diameter in the axial direction. In addition, the rotating shaft 2 has a small-diameter shaft portion 7 having a smaller outer diameter and lower rigidity than a portion adjacent on both sides in the axial direction, at a middle portion in the axial direction. A pair of gears 8a and 8b are supported on both sides in the axial direction of the rotary shaft 2 with the small-diameter shaft portion 7 interposed therebetween so as to be able to rotate synchronously with the rotary shaft 2 by spline engagement or the like. .

In this example, the small-diameter shaft portion 7 constituting the rotating shaft 2 functions as a magnetostrictive effect portion. For this reason, the rotating shaft 2 is made of a magnetic metal. As the magnetic metal, for example, various magnetic steels such as carburized steels such as SCr420 and SCM420 and carbon steels such as S45C specified in JIS can be used. When torque is applied to the rotating shaft 2 and torsional deformation occurs in the small-diameter shaft portion 7, a stress corresponding to the torque (a tensile stress in a direction of 45 ° with respect to the axial direction, and As the compressive stress acts, the magnetic permeability of the small-diameter shaft portion 7 in each direction changes due to the inverse magnetostriction effect.
Note that a magnetostrictive material that functions as a magnetostrictive portion and is separate from the rotating shaft 2 may be fixed to the outer peripheral surface of the small-diameter shaft portion 7 without using the small-diameter shaft portion 7 itself as a magnetostrictive effect portion. . In this case, the annular magnetostrictive material can be externally fitted and fixed to the small-diameter shaft portion 7, or a coating such as plating or a film-shaped magnetostrictive material can be fixed to the outer peripheral surface of the small-diameter shaft portion 7. it can.

  Both ends in the axial direction of the rotating shaft 2 are rotatably supported via a pair of rolling bearings 10a and 10b with respect to a casing (housing) 9 which does not rotate during use. Of the pair of rolling bearings 10a and 10b, one (left side in FIG. 1) first rolling bearing 10a externally fixes the inner ring 11a to one axial end of the rotating shaft 2 (left end in FIG. 1). Then, the outer ring 12a is fixedly fitted inside the casing 9. On the other hand, of the pair of rolling bearings 10a and 10b, the other (rightward in FIG. 1) second rolling bearing 10b connects the inner ring 11b to the other axial end of the rotary shaft 2 (right end in FIG. 1). ), And the outer ring 12 b is internally fixed to the casing 9.

  In the illustrated example, ball bearings whose rolling elements are balls are used as the rolling bearings 10a and 10b, but rolling bearings such as cylindrical roller bearings and tapered roller bearings using rollers and tapered rollers are used as rolling elements. You can also.

  Each of the pair of encoders 3a and 3b is made of magnetic rubber or magnetic resin. In one of the pair of encoders 3a and 3b, one of the first encoders 3a has N poles and S poles alternately and equidistantly arranged in a circumferential direction on an outer peripheral surface which is a detection surface. In the second encoder 3b of the pair of encoders 3a and 3b, the north pole and the south pole are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface that is the detected surface. I have. The number of changes in the magnetic characteristics (the number of poles (the total number of N poles and S poles)) of the surface to be detected per rotation of the first encoder 3a depends on the number of changes in the surface to be detected per rotation of the second encoder 3b. It may be the same as the number of magnetic property changes, or may be different from each other.

  The first encoder 3a is supported and fixed to an inner ring 11a of a first rolling bearing 10a, which is a member that rotates in synchronization with the rotating shaft 2 during use. On the other hand, the second encoder 3b is supported and fixed to the inner ring 11b of the second rolling bearing 10b, which is a member that rotates in synchronization with the rotating shaft 2 during use.

  The detection surfaces of the encoders 3a and 3b are not limited to the structure in which the S poles and the N poles are alternately arranged at equal intervals in the circumferential direction. ) May be alternately arranged at equal intervals in the circumferential direction.

  Of the pair of magnetic sensors 4a and 4b, the first magnetic sensor 4a is supported by the outer ring 12a of the first rolling bearing 10a via the sensor holder 13a, and has a detection unit provided at the tip. , The first encoder 3a is opposed to the detection surface. The second magnetic sensor 4b of the pair of magnetic sensors 4a, 4b is supported by the outer ring 12b of the second rolling bearing 10b via the sensor holder 13b, and is provided at the tip end. The unit is opposed to the detection surface of the second encoder 3b.

  Magnetic detection elements such as a Hall element, a Hall IC, and an MR element (including a GMR element, a TMR element, and an AMR element) are incorporated in the detection units of the pair of magnetic sensors 4a and 4b. For this reason, each of the pair of magnetic sensors 4a and 4b changes the output signal according to the magnetic flux density passing through its own detection unit. Specifically, the first magnetic sensor 4a outputs a pulse-like (rectangular wave) output signal corresponding to a change in the magnetic characteristic of the detected surface of the first encoder 3a that changes with the rotation of the rotating shaft 2. The second magnetic sensor 4b outputs a pulse-like output signal corresponding to a change in magnetic characteristics of the detected surface of the second encoder 3b that changes with the rotation of the rotating shaft 2. In this example, output signals of the first magnetic sensor 4a and the second magnetic sensor 4b are input to the arithmetic unit 6 by wire or wirelessly.

  The magnetostrictive sensor 5 is entirely formed in an annular shape, and is supported by the casing 9 via a sensor holder (not shown). The magnetostrictive sensor 5 is arranged coaxially with the small-diameter shaft 7 and is arranged close to the outer peripheral surface of the small-diameter shaft 7. The magnetostrictive sensor 5 has a coil as a detection unit on the radially inner side, and has a back yoke on the radially outer side as a magnetic path of a magnetic flux generated by the coil. In use, an AC magnetic field is generated around the coil by applying an AC voltage to a coil constituting the magnetostrictive sensor 5. The back yoke is formed in an annular shape by powder metallurgy of a metal such as mild steel or magnetic stainless steel or a magnetic metal, or a synthetic resin mixed with a magnetic material.

  When torque is applied to the rotating shaft 2, torsional deformation occurs in the small-diameter shaft portion 7, and when the magnetic permeability in each direction of the small-diameter shaft portion 7 changes, the magnetic flux passing inside the coil constituting the magnetostrictive sensor 5 changes. That is, the inductance (impedance) of the coil changes. For this reason, the magnetostrictive sensor 5 changes the output signal according to the change in the magnetic flux passing inside the coil. In this example, such an output signal of the magnetostrictive sensor 5 is also input to the arithmetic unit 6 by wire or wirelessly.

  The computing unit 6 is for calculating the torque transmitted by the rotating shaft 2, and has a first function of determining the torque transmitted by the rotating shaft 2 using an output signal of the magnetostrictive sensor 5, and a pair of functions. It has a second function of obtaining the torque transmitted by the rotating shaft 2 using the output signals of the magnetic sensors 4a and 4b.

First, the first function of the arithmetic unit 6 will be described.
When the torque measuring device 1 is used, torque is input to the rotating shaft 2 through one of the gears 8a among a pair of gears 8a and 8b supported in the axial direction with respect to the rotating shaft 2. The torque is taken out from the other gear 8b. At this time, the small-diameter shaft portion 7 of the rotary shaft 2 existing between the pair of gears 8a and 8b is elastically deformed in the torsional direction. Then, since the magnetic permeability in each direction of the small diameter shaft portion 7 changes, the magnetic flux passing through the inside of the coil constituting the magnetostrictive sensor 5 arranged close to the small diameter shaft portion 7 changes. For this reason, the output signal of the magnetostrictive sensor 5 changes according to the change of the magnetic flux passing inside the coil. Therefore, the relationship between the output signal of the magnetostrictive sensor 5 and the torque applied to the rotary shaft 2 is checked in advance, and this relationship is stored in the arithmetic unit 6. 2 can calculate the torque transmitted. The computing unit 6 calculates the torque transmitted by the rotating shaft 2 by such a first function.

Next, the second function of the arithmetic unit 6 will be described.
When the torque measuring device 1 is used, the small-diameter shaft portion 7 is elastically deformed in the torsional direction. The amount of deformation of the small-diameter shaft portion 7 is in accordance with the magnitude of the torque transmitted by the rotating shaft 2. When the small-diameter shaft portion 7 is elastically deformed, the pair of encoders 3a and 3b supported at both axial ends of the rotary shaft 2 are relatively displaced in the rotation direction. When the pair of encoders 3a and 3b are relatively displaced in the rotation direction, the phase difference between the output signals of the pair of magnetic sensors 4a and 4b is changed according to the relative displacement of the pair of encoders 3a and 3b. Change. Therefore, the arithmetic unit 6 calculates the phase difference between the output signal of the first magnetic sensor 4a and the output signal of the second magnetic sensor 4b in order to obtain the torque transmitted by the rotating shaft 2. This phase difference is obtained by measuring the input time of a reference pulse edge, which is the rising edge (or falling pulse edge) of the output signal of the first magnetic sensor 4a, and measuring the next reference pulse edge after measuring the reference pulse edge. The difference can be obtained by calculating the difference between the input time of the rising pulse edge (or the falling pulse edge) of the output signal of the second magnetic sensor 4b which is measured until the input signal has elapsed.

  Here, the absolute value of the magnitude of the phase difference changes according to the rotation speed of the rotating shaft 2, that is, the rotation speed of the pair of encoders 3a and 3b. Therefore, from the phase difference, the torque transmitted by the rotating shaft 2 cannot be determined unless the rotating speed of the rotating shaft 2 is a known constant value. Therefore, in order to remove the influence of the rotation speed of the rotating shaft 2, the phase difference between the output signal of the first magnetic sensor 4 a and the output signal of the second magnetic sensor 4 b is calculated by using the output signal of the first magnetic sensor 4. The phase difference ratio is obtained by dividing by the period. Then, the torque transmitted by the rotating shaft 2 is calculated using the phase difference ratio obtained in this manner or a correction value obtained by removing a component that periodically varies from the phase difference ratio. The calculator 6 also calculates the torque transmitted by the rotating shaft 2 by such a second function.

  The computing unit 6 also has a speed calculation function for obtaining the rotation speed of the rotating shaft 2 by using the output signal of one of the magnetic sensors 4a and 4b out of the pair of magnetic sensors 4a and 4b. That is, when the encoders 3a and 3b rotate with the rotation of the rotating shaft 2, the output signals of the magnetic sensors 4a and 4b change periodically. The frequency and cycle of the change of the output signal of the magnetic sensors 4a and 4b are values corresponding to the rotation speed of the encoders 3a and 3b, that is, the rotation speed of the rotating shaft 2. Therefore, by previously obtaining the relationship between the frequency or cycle of the change of any one of the output signals of the magnetic sensors 4a and 4b and the rotation speed of the encoders 3a and 3b, any one of the magnetic sensors 4a and 4b can be obtained. The rotation speed of the rotating shaft 2 can be obtained based on the frequency or cycle of the change of the output signal.

In particular, the computing unit 6 used in the present example is configured to calculate the value calculated by the first function, which is the measuring method of the magnetostriction, according to the value of the rotation speed of the rotating shaft 2 obtained as described above, and the pulse phase difference Has a function of selecting any one of the values calculated by the second function, which is the measurement method, as the value of the torque transmitted by the rotating shaft 2. Specifically, as shown in FIG. 2, the arithmetic unit 6 calculates the value obtained by the first function during the low speed range (extremely low speed range) where the rotation speed of the rotating shaft 2 is 0 to a predetermined value N or less. the T _M, the value of the torque rotating shaft 2 is transmitted, the rotational speed of the rotary shaft 2 is large high-speed range than the predetermined value N, the value T _P determined by the second function, the rotary shaft 2 is transmitted The value is the torque. That is, the computing unit 6 has a function of selecting a value obtained by the magnetostrictive measurement method in a low speed range, and selecting a value obtained by a pulse phase difference measurement method in a high speed range.

According to the torque measuring device 1 of the present embodiment as described above, torque can be stably measured in a wide range from a state where the rotating shaft 2 is stopped to a state where the rotating shaft 2 is rotating at high speed.
That is, the torque measuring device 1 of the present embodiment not only includes the two measuring methods, ie, the magnetostrictive measuring method and the pulse phase difference measuring method, but can also use the advantages of each method ( The functions of the arithmetic unit 6 are devised so that they can complement each other.
Specifically, the output signal of the magnetostrictive sensor 5 changes due to the elastic deformation of the small-diameter shaft portion 7 regardless of whether the rotating shaft 2 is rotating. Therefore, in this example, between the rotational speed of the rotary shaft 2 are 0 predetermined value N or less of the low speed range, the value T _M obtained by the first function of using the output signal of the magnetostrictive sensor 5, the rotational axis 2 is adopted as the value of the transmitted torque. Therefore, the torque transmitted by the rotating shaft 2 can be obtained even under the condition that the rotating shaft 2 is stopped.

On the other hand, the generation frequency of the pulse of the output signal of the pair of magnetic sensors 4a and 4b increases as the rotation speed of the rotating shaft 2 increases. Therefore, in this example, a high-speed range where the rotation speed of the rotation shaft 2 is greater than the predetermined value N, 1 pair of magnetic sensors 4a, the value T _P determined by a second function of using the output signal of the 4b, rotation It is adopted as the value of the torque transmitted by the shaft 2. Therefore, the torque measurement frequency can be increased, excellent responsiveness can be ensured, and the torque measurement accuracy can be increased.
As a result, according to the torque measuring device 1 of the present example, the torque can be stably measured in a wide range from the state where the rotating shaft 2 is stopped to the state where the rotating shaft 2 is rotating at high speed.

  Further, in this example, the torque can be obtained simultaneously by two types of methods: a magnetostrictive measuring method using the magnetostrictive sensor 5 and a pulse phase difference measuring method using the pair of magnetic sensors 4a and 4b. . For this reason, even if a failure (step-out) occurs in any of the sensors, it is possible to prevent a problem that torque cannot be obtained at all. That is, redundancy (backup function) can be provided for the torque measurement. In addition, from the aspect of providing such redundancy, the arithmetic unit 6 simultaneously calculates the torque based on both the first function and the second function regardless of the rotation speed of the rotating shaft 2. Then, one of the values is selected as the value of the torque transmitted by the rotating shaft 2 according to the value of the rotation speed. However, from the viewpoint of reducing the number of operations performed by the arithmetic unit 6, the first function and the second function are not executed simultaneously, but one of the first function and the second function is performed in accordance with the rotation speed. The torque can be calculated based on one of the functions.

[Second Example of Embodiment]
A second example of the embodiment will be described with reference to FIG. The arithmetic unit 6 (see FIG. 1) used in the present example obtains the torque by the first function of obtaining the torque by the magnetostrictive measurement method and the torque by the pulse phase difference measurement method described in the first example of the embodiment. In addition to the second function, as a third function, when the rotation speed of the rotating shaft 2 (see FIG. 1) is within a predetermined speed range, the value obtained by the first function and the value obtained by the second function are obtained. It has a function of obtaining the torque transmitted by the rotating shaft 2 by using both of the values.

Specifically, as shown in FIG. 3, the third function is a value obtained by the first function when the rotation speed of the rotary shaft 2 is in a middle speed range from a predetermined value N1 to a predetermined value N2. The value of the arithmetic average (arithmetic average) of T _M and the value T _P obtained by the second function is adopted as the value of the torque transmitted by the rotating shaft 2. That is, when the rotation speed Nx of the rotating shaft 2 is in the range of N1 <Nx <N2, the computing unit 6 calculates the value T _M obtained by the magnetostrictive measurement method and the pulse phase difference measurement method. A value {( _TM + _TP ) / 2}, which is a half of the sum of the obtained value _TP and the calculated value TP, is output as a torque value (T) transmitted by the rotating shaft 2. Further, in this embodiment, in the low speed range of the rotational speed of the rotary shaft 2 is 0 to a predetermined value N1, the value T _M obtained by the first function, the value of the torque rotating shaft 2 is transmitted, the rotation shaft 2 the rotational speed of a large high-speed range than the predetermined value N2, the value T _P determined by the second function, the rotary shaft 2 is adopted as the value of the torque transmitted.

According to the torque measuring device of the present embodiment as described above, the rotation speed of the rotating shaft 2 is increased from the predetermined value N1 which is around the predetermined value N to the predetermined value N2, as compared with the case of the first example of the embodiment. In the medium speed range, it is possible to suppress the calculated value of the arithmetic unit 6 from varying in magnitude.
Other configurations and operational effects are the same as those of the first example of the embodiment.

[Third Example of Embodiment]
A third example of the embodiment will be described with reference to FIG. The arithmetic unit 6 (see FIG. 1) used in this example has a third function, as in the second example of the embodiment, when the rotation speed of the rotating shaft 2 (see FIG. 1) is within a predetermined speed range. In addition, it has a function of calculating the torque transmitted by the rotating shaft 2 using both the value obtained by the first function and the value obtained by the second function.

Specifically, as shown in FIG. 4, the third function is a value obtained by the first function when the rotation speed of the rotary shaft 2 is in a middle speed range from a predetermined value N1 to a predetermined value N2. A weighted average value obtained by weighting the value T _M and the value T _P obtained by the second function according to the rotation speed of the rotation shaft 2 is defined as a value of the torque transmitted by the rotation shaft 2. More specifically, the magnetostrictive measurement method is advantageous when the rotation speed of the rotation shaft 2 is low, and the pulse phase difference measurement method is advantageous when the rotation speed of the rotation shaft 2 is high. Therefore, the value T _M obtained by the first function is weighted more as the rotation speed of the rotary shaft 2 is smaller, and the value T _P obtained by the second function is weighted as the rotation speed of the rotary shaft 2 is higher. Weight heavily. For this, the rotational speed Nx of the rotary shaft 2, N1 <Nx <when in the range of N2, the importance of the value _{T M} obtained by the first function (weight) and N2-Nx, second severity value _{T P} determined by function (weight) is set to Nx-N1. And in this embodiment, these weighted average in consideration of the importance of _{{T M (N2-Nx)} / (N2-N1) + T P (Nx-N1) / (N2-N1)}, the rotation shaft 2 transmits To be applied (T). Also in this embodiment, in the low speed range of the rotational speed of the rotary shaft 2 is 0 to a predetermined value N1, the value T _M obtained by the first function, the value of the torque rotating shaft 2 is transmitted, the rotation shaft 2 the rotational speed of a large high-speed range than the predetermined value N2, the value T _P determined by the second function, the rotary shaft 2 is adopted as the value of the torque transmitted.

According to the torque measuring device of the present embodiment as described above, the rotation speed of the rotating shaft 2 is increased from the predetermined value N1, which is around the predetermined value N, as compared with the first and second examples of the embodiment. Variations in the calculated value of the computing unit 6 in the medium speed range up to the predetermined value N2 can be more effectively suppressed.
Other configurations and operational effects are the same as those of the first example of the embodiment.

[Fourth Example of Embodiment]
A fourth example of the embodiment will be described with reference to FIG. The arithmetic unit 6 (see FIG. 1) used in this example has a third function, as in the second and third examples of the embodiment, in which the rotation speed of the rotating shaft 2 (see FIG. 1) is a predetermined speed. When the value is in the range, a function is provided for determining the torque transmitted by the rotating shaft 2 using both the value determined by the first function and the value determined by the second function.

Specifically, the third feature, when the rotational speed of the rotary shaft 2 is in the speed range within the predetermined value N1 to the predetermined value N2, the value T _M and the second function determined by the first function the value of the geometric mean (geometric mean) between the value T _P determined by the rotating shaft 2 is adopted as the value of the torque transmitted. That is, when the rotation speed Nx of the rotating shaft 2 is in the range of N1 <Nx <N2, the computing unit 6 calculates the value T _M obtained by the magnetostrictive measurement method and the pulse phase difference measurement method. the value of the geometric mean of the values _{T P} obtained ^{_{{(T M × T P)}} 1/2}, and outputs as the value of the torque rotating shaft 2 is transmitted (T). Alternatively, the calculator 6, the value _{{T M (N2-Nx)} / (N2-N1)} was weighted according to the rotational speed of the rotary shaft 2 to the value _{T M} obtained by the measurement method of the magnetostrictive, pulse of a value obtained by weighting in accordance with the rotational speed of the rotary shaft 2 to the value _{T P} determined by the measurement method of the phase-difference formula _{{T P (Nx-N1)} / (N2-N1)}, geometric mean value {{ the _{T M (N2-Nx) /} (N2-N1) × T P (Nx-N1) / (N2-N1)} 1/2}, the rotary shaft 2 is outputted as the value of the torque transmitted (T) You can also. In any case, if the two measured values, that is, the value T _M obtained by the measurement method of the magnetostriction method and the value T _P obtained by the measurement method of the pulse phase difference method are mutually different values, a synergistic effect is obtained. The average value is smaller than the arithmetic average value and the weighted average value (the geometric average value <the arithmetic average value, the weighted average value). It has a relationship as shown in FIG. Therefore, the torque value can be managed by using the relationship between the actually measured value and each average value.
Other configurations and operational effects are the same as those of the first to third examples of the embodiment.

[Fifth Example of Embodiment]
A fifth example of the embodiment will be described with reference to FIG. In the torque measuring device 1a of the present embodiment, a pair of magnetic sensors 4a, 4b and a magnetostrictive sensor 5 are provided around a rotating shaft 2a by using a common sensor holder 13c, and a casing 9a which does not rotate during use. The structure to support against is adopted.

  For this purpose, the rotating shaft 2a is disposed so as to pass through the inside of the mounting hole 14 formed in the casing 9a. Further, a pair of encoders 3a and 3b are externally fitted and fixed to a portion existing on the radially inner side of the mounting hole 14 and the vicinity thereof on the outer peripheral surface of the rotating shaft 2a while being spaced apart in the axial direction. Of the pair of encoders 3a and 3b, one (left side in FIG. 6) first encoder 3a includes a ring-shaped support ring 15a and a permanent magnet 16a fixed to the outer peripheral surface of the support ring 15a. ing. On the other hand, the other (rightward in FIG. 6) second encoder 3b includes a support ring 15b having a crank-shaped cross section and a permanent magnet 16b fixed to the outer peripheral surface of the support ring 15b. Further, on one side (left side in FIG. 6) in the axial direction of a portion of the outer peripheral surface of the rotary shaft 2a where the first encoder 3a is externally fixed, a magnetostrictive effect is more excellent than the rotary shaft 2a. A magnetostrictive material 17 made of magnetic metal is externally fitted and fixed. When the magnetostriction characteristic of the rotating shaft 2a itself can be used, the magnetostrictive material 17 can be omitted.

  Further, an annular sensor holder 13c is fixedly fitted in a mounting hole 14 formed in the casing 9a. The sensor holder 13c has a substantially L-shaped cross section, and the inside diameter of one half in the axial direction is smaller than the inside diameter of the other half in the axial direction. In the sensor holder 13c having such a shape, the magnetostrictive sensor 5 is supported and fixed on the inner peripheral surface of one half in the axial direction. In the present embodiment, the magnetostrictive sensor 5 has a coil 18 on the radial inside and a back yoke 19 on the radial outside, and the back yoke 19 is one of the axial half of the sensor holder 13c. It is supported and fixed on the peripheral surface. A pair of magnetic sensors 4a and 4b are supported and fixed to the inner peripheral surface of the other half in the axial direction of the sensor holder 13c. Thus, the magnetostrictive sensor 5 is arranged coaxially with the magnetostrictive material 17 and is arranged close to the outer peripheral surface of the magnetostrictive material 17. In addition, the detection units of the pair of magnetic sensors 4a and 4b are respectively opposed to the detection surfaces of the pair of encoders 3a and 3b.

  In the torque measuring device 1a of the present example, for example, torque is input to the rotating shaft 2a from a gear (not shown) fixed to one end in the axial direction of the rotating shaft 2a, and the torque is input to the other end of the rotating shaft 2a in the axial direction (not shown). When the torque is extracted from the gears, elastic deformation occurs in a portion of the rotating shaft 2a between the pair of gears around which the various sensors 4a, 4a, and 5 are disposed. Therefore, also in the case of the present example, the computing unit 6 (see FIG. 1) uses the output signal of the magnetostrictive sensor 5 to determine the torque transmitted by the rotating shaft 2a based on the first function. Based on the second function, the torque transmitted by the rotating shaft 2a is obtained using the phase difference between the output signals of the pair of magnetic sensors 4a, 4b.

In this example having the above-described configuration, the pair of magnetic sensors 4a and 4b and the magnetostrictive sensor 5 can be supported using the common sensor holder 13c, so that the number of parts can be reduced. In addition, the size and weight of the entire device can be reduced.
Other configurations and operational effects are the same as those of the first example of the embodiment.

  When the torque measuring device of the present invention is used by being incorporated in a power train of an automobile, the target device is not particularly limited. For example, an automatic transmission (AT), a belt-type continuously variable transmission, a toroidal-type continuously variable transmission, an automatic manual transmission (AMT), a dual-clutch transmission (DCT), and other transmissions that perform gear shifting by vehicle-side control, or a transfer; Manual transmission (MT) can be targeted. Further, the driving method (FF, FR, MR, RR, 4WD, etc.) of the target vehicle is not particularly limited.

  The torque measuring device of the present invention is not limited to a rotating shaft constituting a power train of an automobile. For example, a rotating shaft of a windmill (main shaft, rotating shaft of a speed increasing device), a roll neck of a rolling mill, a rotating shaft of a railway vehicle ( Rotating shafts for various mechanical devices such as axles, rotating shafts for reduction gears, rotating shafts for machine tools (main shafts, rotating shafts for feed systems), rotating shafts for construction machines, agricultural machines, household electric appliances, motors, etc. It can also be used by incorporating it into a computer.

  The magnetostrictive sensor used in the torque measuring device of the present invention may be any sensor that passes (penetrates) its own detecting unit and changes an output signal according to a magnetic flux that changes according to the magnetic permeability of the magnetostrictive effect unit. The specific configuration is not particularly limited. For example, in addition to excitation by a coil, a configuration in which a magnetic detection element such as a Hall element is incorporated in the detection unit may be adopted. Further, the material constituting the magnetostrictive effect portion may be any material that exhibits the reverse magnetostrictive effect at least to the extent that it does not hinder the detection of torque, and is not limited to those specifically exemplified in this specification. Absent.

  The present invention can be implemented by appropriately combining the structures of the examples in the embodiments as long as no contradiction occurs.

DESCRIPTION OF SYMBOLS 1, 1a Torque measuring device 2, 2a Rotary shaft 3a, 3b Encoder 4a, 4b Magnetic sensor 5 Magnetostrictive sensor 6 Calculator 7 Small diameter shaft portion 8a, 8b Gear 9, 9a Casing 10a, 10b Rolling bearing 11a, 11b Inner ring 12a, 12b Outer ring 13a, 13b, 13c Sensor holder 14 Mounting hole 15a, 15b Support ring 16a, 16b Permanent magnet 17 Magnetostrictive material 18 Coil 19 Back yoke

Claims (8)

A rotating shaft having a magnetostrictive effect portion that transmits torque during use, and whose magnetic permeability changes according to the transmitted torque,
Magnetostriction that is supported by a portion that does not rotate during use in a state of being disposed close to the magnetostrictive effect portion, passes through its own detection portion, and changes an output signal according to a magnetic flux that changes according to the magnetic permeability of the magnetostrictive effect portion. Sensors and
A pair of encoders that alternately change the characteristics of each detected surface in the circumferential direction and are supported directly or via another member with respect to the rotation axis,
A pair of magnetic sensors supported on a portion that does not rotate during use, with the detection unit facing each of the detection surfaces of the encoder;
A first function of obtaining a torque transmitted by the rotating shaft based on an output signal of the magnetostrictive sensor, and a torque transmitted by the rotating shaft based on a phase difference between output signals of the pair of magnetic sensors. An arithmetic unit having a second function required;
A torque measuring device equipped with:   The computing unit selects one of a value obtained by the first function and a value obtained by the second function according to a rotation speed of the rotation shaft, and selects a torque transmitted by the rotation shaft. The torque measuring device according to claim 1, wherein   When the rotation speed of the rotating shaft is between 0 and a predetermined value N or less, the computing unit sets the value obtained by the first function as a value of the torque transmitted by the rotating shaft, and the rotation speed of the rotating shaft is 3. The torque measuring device according to claim 2, wherein when the value is larger than the predetermined value N, a value obtained by the second function is set as a value of a torque transmitted by the rotating shaft.   The arithmetic unit, as a third function, when the rotation speed of the rotating shaft is in a predetermined speed range, both the value obtained by the first function and the value obtained by the second function The torque measuring device according to claim 1, wherein the torque measuring device has a function of determining a torque transmitted by the rotation shaft by utilizing the function.   In a speed range where the rotation speed of the rotating shaft is from 0 to a predetermined value N1, the computing unit determines a value obtained by the first function as a value of a torque transmitted by the rotating shaft, and calculates a rotation speed of the rotating shaft. In the speed range from the predetermined value N1 to the predetermined value N2, the value obtained by the third function is used as the value of the torque transmitted by the rotating shaft, and the rotating speed of the rotating shaft is larger than the predetermined value N2. The torque measuring device according to claim 4, wherein in a speed range, a value obtained by the second function is a value of a torque transmitted by the rotating shaft.   The third function of the arithmetic unit is a value of an arithmetic average of a value obtained by the first function and a value obtained by the second function, which is a value of a torque transmitted by the rotating shaft. The torque measuring device according to any one of claims 4 to 5, wherein the torque measuring device is a device for measuring torque.   The third function of the arithmetic unit is a weighted average value obtained by weighting the value obtained by the first function and the value obtained by the second function according to the rotation speed of the rotating shaft. The torque measuring device according to any one of claims 4 to 5, wherein the torque is a value of a torque transmitted by the rotating shaft.   The method according to claim 7, wherein the value obtained by the first function is heavily weighted as the rotation speed of the rotary shaft is small, and the value obtained by the second function is weighted heavily as the rotation speed of the rotary shaft is large. The torque measuring device described.

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