JP2794944B2 - Engine torque detector for propeller aircraft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a torque detection device that detects engine torque in a propeller aircraft.

[Prior art]

Conventionally, a device disclosed in Japanese Utility Model Laid-Open No. 55-81740 has been known as this type of device. According to this device, a load sensor is provided on the wing bearing portion of the propeller, and the torque of the engine is detected based on the detection result by the sensor.

In the conventional device described above, a gyro moment is generated in the propeller by the rotation of the propeller, and when trying to detect the torque of the engine based on the load generated in the wing support portion of the propeller, There was a problem that accuracy was deteriorated by the influence of the gyro moment. SUMMARY An advantage of some aspects of the invention is to provide a torque detection device that can accurately detect engine torque in a propeller aircraft.

[Means for Solving the Problems]

In order to achieve the above object, a structural feature of the present invention is that an input shaft that is integrally connected to a crankshaft of an engine and receives a rotational driving force of the engine is integrally connected to a propeller. An output shaft, a casing accommodating a part of the input shaft and the output shaft, and a seal member provided between the input shaft and the output shaft, respectively; and the input shaft and the output shaft accommodated in the casing while being accommodated in the casing. And a deceleration mechanism for transmitting the rotational driving force of the engine to the output shaft while reducing the rotation of the input shaft, wherein the input shaft is made of a magnetic material. And a seal member provided between the input shaft and the casing is disposed outside the casing so as to face the surface of the input shaft, and is provided by the rotational driving force. And the stress sensor of the magnetostrictive detecting the shear stresses generated on the surface of the filling power shaft is connected to the stress sensor in that a torque signal output means for outputting a signal representative of the torque of the engine.

Actions and effects of the present invention

In the present invention configured as described above, the input shaft that is twisted by the rotational driving force of the engine is formed of a magnetic material, and the magnetostrictive stress sensor disposed facing the surface of the input shaft is driven by the rotating shaft. When the shearing stress generated on the surface of the input shaft by the driving force is detected, the torque signal output means outputs a signal representing the torque of the engine based on the detection result of the stress sensor, so that the torque of the engine is detected. . In the drive system of the propeller, since the gyro moment generated in portions other than the output shaft is small, according to the present invention, the engine torque can be accurately detected without being affected by the gyro moment. Further, according to the present invention, since the magnetostrictive stress sensor is disposed outside the casing with respect to the seal member provided between the input shaft and the casing, the output lead wire of the sensor is connected to the casing. When the oil is drawn out, it is not necessary to consider the sealing property of the oil at the drawing part.

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an aircraft speed reducer to which the present invention is applied. The speed reducer includes a casing A, an input shaft 11, an output shaft 12, a reduction gear train (reduction mechanism) B, and the like. The input shaft 11 is supported by a front case 13 and a rear case 14 of the casing A, and is slidable in the axial direction with a rubber coupling 16 assembled to a crankshaft 15 of the engine at a rear end (right end in the drawing). The input gear 17 is coaxially and rotatably fitted with the hollow input gear 17 at the front end (the left end in the figure) so as to be integrally rotatable. Positioning has been done. In addition, a seal member 19 is attached between the outer periphery of the center of the input shaft 11 and the rear case 14. The input gear 17 is rotatably supported by both cases 13 and 14 via a pair of radial bearings 21 and 22 and one thrust bearing 23, and is configured to be integrally rotated by the input shaft 11. And is always engaged with the intermediate gear 24 as shown in FIG. The inner races of the front bearings 21 and 23 are fastened by fasteners 25 screwed to the shaft of the input gear 17.
, The outer ring of the thrust bearing 23 is integrally fixed to the front case 13 by a retainer 27 fixed to the front case 13 using a fastener. The intermediate gear 24, as shown in FIG.
A pair of front and rear radial bearings 31, 32 are rotatably supported by the shaft 4. The intermediate gear 24 is also always fitted with an output gear 33 (see FIG. 1) which is spline-fitted on the output shaft 12 and rotates integrally with the output shaft 12 as shown in FIG. The input gear 17 and the output gear 33 are connected so that power can be transmitted. On the other hand, the output shaft 12 is formed in a hollow shape as shown in FIG. 1, and is rotatable between the two cases 13 and 14 via a pair of radial bearings 34 and 35 and one thrust bearing 36. An annular flange 37 that is supported at the front end
Is mounted with a variable pitch propeller (not shown). A thin cylindrical race 42 having a diameter toward the rear is attached to the neck at the front end of the output shaft 12.
The inner rings of the front and rear bearings 34, 36 are integrally fixed to the output shaft 12 together with the output gear 33 by fasteners 38 screwed to the output shaft 12, and the outer ring of the thrust bearing 36 is fastened to the front case using fasteners. It is integrally fixed to the front case 13 by a retainer 41 fixed to the 13. Further, seal members 43a and 43b are assembled between the race 42 and the front case 13 mounted on the front end neck of the output shaft 12 and between the race 42 and the output shaft 12. In such a speed reducer, the input shaft 11 is made of a magnetic material, and is fastened near the mounting position of the seal member 19 on the rear case 14 so that the magnetostrictive torque sensor 44 faces the central outer peripheral surface of the input shaft 11. The tool 45 is positioned and fixed. The mounting position of the magnetostrictive torque sensor is between a portion of the input shaft 11 connected to the crankshaft of the engine and a portion of the input shaft 11 fixed to the input gear 17, that is, the input shaft 11 Any position may be used as long as it faces a portion that transmits the rotational driving force of the engine by the torsional rigidity. The magnetostrictive torque sensor 44 includes a U-shaped excitation core and a detection core, each of which is wound as shown schematically in FIG.
The U-shaped openings are arranged in the same direction and are arranged orthogonally, and the opening surfaces of the respective cores are arranged to face the magnetic body to be detected to which a load is applied, and one of the windings is arranged. An AC current is applied to the wire (excitation coil) to excite the magnetic body to be detected, and the load is detected based on the AC current flowing through the other winding (detection coil) according to the load. The magnetostrictive torque sensor 44 is connected to an output signal conversion circuit 50 shown in FIG.
Are an oscillator 51 and an amplifier 52 that generate an AC signal to be supplied to an exciting coil of the magnetostrictive torque sensor 44, and an output signal output from a detection coil of the magnetostrictive torque sensor 44 is linear with respect to the detected torque. An addition / subtraction signal processing circuit 53, a temperature compensation circuit 54 for preventing a detection signal output through the addition / subtraction signal processing circuit 53 from changing with a temperature change, and a rotation speed of the input shaft 11. It comprises a rotation speed compensation circuit 55 for preventing the detection signal from fluctuating, and an amplifier 56 for amplifying the detection signal. Here, the addition / subtraction signal processing circuit 53 removes an AC signal component that does not change with torque to improve the linearity of the output signal from the detection coil.
The amplification and phase shift circuit in the above amplifies and shifts the phase of the excitation signal output from the amplifier 52 to produce a signal equivalent to the AC signal component and adds the signal to the detection signal,
53b creates a DC voltage corresponding to the torque based on the combined signal, and a subtraction circuit 53c subtracts the DC voltage component generated by the addition circuit 53a from the DC voltage. FIG. 5 shows the characteristics of the output signal of the addition / subtraction signal processing circuit 53 when the phase is shifted by 24 ° and 150 ° in the adder circuit 53a. ing. Further, the temperature compensation circuit 54 has a temperature sensor, and performs temperature compensation based on the detection signal of the temperature sensor. The rotation speed compensation circuit 55 has a rotation speed sensor. The rotational speed is compensated based on the rotational speed. The output voltage of the amplifier 56 is supplied to a meter provided at a position in the cockpit that is visible to a pilot, and the meter displays the torque of the engine corresponding to the voltage. Next, the operation of the embodiment configured as described above will be described. When the engine is started, the crankshaft of the engine
15 rotates, and the rotational driving force of the engine is transmitted to one end of the input shaft 11 connected to the crankshaft 15 via the rubber coupling 16. The rotational driving force of the engine is
Input gear connected to the other end of the coaxial 11 with the torsional rigidity of 11
The variable pitch propeller (not shown) is transmitted from the motor 17 to the output shaft 12 via the intermediate gear 24 and the output gear 33, and is connected to the annular flange 37 of the output shaft 12. At this time, in the input shaft 11, a force for rotating the input shaft from the crankshaft 15 is applied to one end, and a force for rotating the propeller against the load of the variable pitch propeller is applied to the other end. , A shear force τ is applied to the surface of the input shaft 11.
Occurs. This is represented by a tensile stress + δ in the + 45 ° direction and a compressive stress −δ in the −45 ° direction with respect to the axial direction. Input shaft
11 is made of an iron-based alloy, and the saturation magnetostriction constant λ of the iron-based alloy is
Since s is positive, the permeability increases according to the tensile stress,
The magnetic permeability decreases according to the compressive stress. FIG. 6 shows the projection of the core on the surface of the input shaft 11 in the magnetostrictive torque sensor 44. When the magnetic resistance of the shaft surface is represented by r1 to r4, the magnetic circuit composed of the exciting coil, the detection coil, and the shaft surface becomes The Whitstone bridge is configured as shown in FIG. The bridge is balanced when the permeability is uniform,
When the magnetic permeability changes according to the tensile stress and the compressive stress, the magnetic resistances r1 to r4 change in proportion to the change in the magnetic permeability, and the equilibrium of the bridge is broken. Initially, the engine is not running again. Since no shear force is generated on the input shaft 11, the magnetic permeability can be assumed to be uniform, and the magnetic resistances r1 and r2 and the magnetic resistances r3 and r4 shown in FIG. I have. Therefore, even if an alternating current is applied to the excitation coil of the magnetostrictive torque sensor 44 by the oscillator 51 and the amplifier 52, no current basically flows through the detection coil. However, since there is a deviation from the orthogonal arrangement of the excitation core and the detection core in the magnetostrictive torque sensor 44, an easy magnetization direction on the input shaft, residual distortion, and the like, an AC signal component that does not change due to torque flows as described above. Even if such an AC signal component is output from the detection coil, since the addition / subtraction signal processing circuit 53 removes the AC signal component, the signal is output via the temperature compensation circuit 54, the rotation speed compensation circuit 55, and the amplifier 56. The output voltage of the output signal conversion circuit 50 becomes "0" V. On the other hand, it is assumed that the engine starts and the crankshaft 15 starts to rotate clockwise with respect to the traveling direction (rightward in the figure). Then, a force is applied to the rear end of the input shaft 11 to rotate the input shaft 11 clockwise with respect to the traveling direction by the crankshaft 15, and the front end of the input shaft 11 is advanced by the load of the variable pitch propeller. Since a force is applied to rotate in the counterclockwise direction with respect to the direction, the above-described shearing force τ is generated on the surface of the input shaft 11. The shear force τ is, as shown in FIG. 3, a tensile stress + 45 ° with respect to the axial direction.
δ and the compressive stress −δ in the −45 ° direction, the magnetic permeability in the + 45 ° direction increases with respect to the axial direction, and −45 ° in the axial direction.
The magnetic permeability in the ゜ direction decreases. That is, since the magnetic permeability in the directions of the magnetic resistances r1 and r4 shown in FIG. 6 increases, the resistance values of the magnetic resistances r1 and r4 decrease, and the magnetic permeability in the directions of the magnetic resistances r2 and r3 decreases. The resistance values of the magnetic resistances r2 and r3 increase. Therefore, the balance of the Whitstone bridge is broken, and an electromotive force is generated in the detection coil of the magnetostrictive torque sensor 44 according to the change in the magnetic permeability. The AC signal generated in the detection coil of the magnetostrictive torque sensor 44 has an AC signal component irrelevant to torque removed by the above-described addition / subtraction signal processing circuit 53, and furthermore, the temperature compensation circuit 54 and the rotation speed compensation circuit 55 change the temperature with respect to a change in temperature. The variation with respect to the rotation speed and the rotation speed is compensated and amplified by the amplifier 56. At this time, the torque applied to the input shaft 11 and the output voltage of the addition / subtraction signal processing circuit 53 are in a proportional relationship as shown in FIG.
Output voltage changes proportionally. The output voltage of the amplifier 56 is supplied to a meter in the cockpit, and the meter displays the torque of the engine corresponding to the voltage, so that the pilot can detect the torque of the engine. In the above-described embodiment, the magnetostrictive torque sensor 44 is mounted facing the outside of the center of the input shaft 11, but may be mounted facing another shaft member. In the present embodiment, although the configuration is not such that the rotational driving force is transmitted by the torsional rigidity in the shaft portion of the intermediate gear 24,
The intermediate gear 24, an intermediate gear shaft, an intermediate input gear fixed to the intermediate gear shaft and meshing with the input gear 17, and an intermediate output gear fixed to the intermediate gear shaft and meshing with the output gear 33. , And the magnetostrictive torque sensor 44 may be attached to a portion of the intermediate gear shaft between the fixed positions of the intermediate input gear and the intermediate output gear so as to face each other. However, when the same magnetostrictive torque sensor 44 is provided inside the casing A, it is necessary to draw out the output lead wire of the sensor outside the casing A. Therefore, it is necessary to consider the oil sealing property at the drawing part. On the other hand, as in the present embodiment, the magnetostrictive torque sensor 44 is attached to the outside of the center of the input shaft 11 connected to the crankshaft 15 of the engine so as to face the outside of the casing A. It can be disposed, and there is an effect that it is not necessary to consider oil sealing properties. In addition, since the input shaft 11 is closest to the crankshaft of the engine as compared with other members of the speed reduction mechanism, the torque can be accurately detected.

[Brief description of the drawings]

1 and 2 are sectional views of a speed reducer to which the present invention is applied, FIG. 3 is a view showing a schematic configuration of a magnetostrictive torque sensor,
FIG. 4 is a block diagram of an output signal conversion circuit, FIG. 5 is a diagram showing characteristics of input / output signals in the output signal conversion circuit, and FIG.
FIG. 7 is a projection view of the core of the magnetostrictive torque sensor on the input shaft surface, and FIG. 7 is a diagram showing a magnetic circuit including the exciting coil, the detection coil, and the shaft surface. Description of symbols A: casing, 11: input shaft, 12: output shaft, B:
... reduction gear train, 44 ... magnetostrictive torque sensor, 50 ... output signal conversion circuit.

Continuation of the front page (72) Inventor Kazuya Arakawa 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-52-73209 (JP, A) JP-A-63-33634 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01L 5/00

Claims (1)

(57) [Claims] An input shaft integrally connected to a crankshaft of an engine to receive a rotational driving force of the engine, an output shaft integrally connected to a propeller, and one of the input shaft and the output shaft. And a casing that accommodates the components and seal members provided between the input shaft and the output shaft, and a casing that is accommodated in the casing and that is provided between the input shaft and the output shaft and rotates the input shaft. A propeller aircraft equipped with an aircraft speed reducer comprising a speed reduction mechanism that transmits the rotational driving force of the engine to the output shaft while decelerating the engine, wherein the input shaft is made of a magnetic material, and the input shaft and the casing are A shear stress generated on the surface of the input shaft due to the rotational driving force is disposed outside the casing with respect to the seal member provided therebetween and facing the surface of the input shaft. An engine torque detecting device for a propeller aircraft, comprising: a magnetostrictive type stress sensor; and a torque signal output unit connected to the stress sensor for outputting a signal representing the torque of the engine.