JP2001272204A - Torsion quantity measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque measuring apparatus which enables miniaturization and a lower cost with a simple structure. SOLUTION: In the torsion quantity measuring apparatus, which has an input side rotor 2 and an output side rotor 4 arranged free to rotate circumferentially and detects a relative torsion quantity between the input side rotor 2 and the output side rotor 4, an input side stator 1 is installed at a position facing the input side rotor 2 in the circumferential direction thereof at a prescribed interval and an output side stator 3 at a position circumferentially facing the output side rotor 4 at a prescribed interval. The input side stator 1 and the output side stator 3 have respectively an exciting winding and output windings 5 and 6, and the output winding of the input side stator 1 and the output winding of the output side stator 3 are interconnected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering device for an automobile, in which an input shaft is rotated by rotating an input shaft to rotate an input shaft and an output shaft while twisting a torsion bar. The present invention relates to a torsion amount measuring device that detects and calculates a torque by detecting a relative rotation amount with respect to an output shaft via a resolver.

[0002]

2. Description of the Related Art In the conventional apparatus shown in FIGS. 7 to 10, one end of a torsion bar 101 is fixed to an input shaft (not shown), and the other end is fixed to an output shaft (not shown). When the handle is rotated to rotate the input shaft, the input shaft and the output shaft rotate while twisting the torsion bar 101. The input torque can be detected by detecting the torsion amount of the torsion bar 101, that is, the relative rotation amount of both shafts at this time. The resolver mechanism detects the relative rotation amount between the two shafts as described above, and the resolver mechanism will be specifically described below.

An input-side cylindrical rotor 102 is fixed to the input shaft side of the torsion bar 101, and an output-side cylindrical rotor 103 is fixed to the output shaft side. The housing 104 surrounds both the rotors 102 and 103. As shown in FIG. 8, an annular first yoke 105 is provided on the inner periphery of the housing 104, and the first coil 10 is provided in the first yoke 105.
6 are provided. An annular second yoke 1 facing the first yoke 105 is provided on the outer periphery of the input-side cylindrical rotor 102.
07 is fixed, and the second coil 108 is also provided therein. Then, the first yoke 105 and the first coil 1
06, the second yoke 107 and the second coil 108 constitute a magnetic circuit (rotary transformer).

Further, a third yoke 109 is fixed to the input side cylindrical rotor 102 on the circumference thereof. Around the third yoke 109, a third coil 110 composed of two types of coils whose phases are shifted by 90 ° is wound, and the third coil 110 is connected to the second coil 1.
08. On the other hand, the third yoke 109 and the third coil 110
And a fourth yoke 111 and a fourth coil 112 that face each other. The fourth coil 112, like the third coil 110, is composed of two types of coils whose phases are shifted by 90 °. These components constitute an input-side resolver mechanism R1. Note that reference numeral 113 in the figure denotes the first coil 1.
A lead wire connected to 06 and a lead wire 114 connected to the fourth coil 112 are all drawn out of the housing 104.

The input-side cylindrical rotor 102 and the housing 10
4, the input-side resolver mechanism R as described above.
1 is provided, but an output-side resolver mechanism R2 exactly the same as that on the input side is also provided between the output-side cylindrical rotor 103 and the housing 104. FIG. 9 is a circuit diagram of the resolver mechanism.

When the torsion bar 101 is twisted and an AC voltage ER1 is applied to the first coil 106, the first yoke 105 and the second yoke 107
And an AC voltage is induced in the second coil 108 according to the magnetic flux density at that time. Since the second coil 108 is connected to the third coil 110,
An AC voltage is also generated in the third coil 110. However, since the third coil 110 is composed of two types of coils whose phases are shifted by 90 °, the generated voltages are also shifted by 90 ° in phase. The AC voltage generated in the third coil 110 induces an AC voltage in the fourth coil 112, and the AC voltage of the fourth coil 112
4 is taken out of the housing 104.

The output voltages ES1 and ES2 taken out of the housing 104 are as follows. ES1 = kER1 × cosθ1 ES2 = kER1 × sinθ1

[0008] Here, k represents a transformation ratio. The output voltage characteristics at this time are as shown in FIG. Θ1 can be calculated from the above two equations. This angle θ1
Is the rotation angle of the input-side cylindrical rotor 2.
The θ1 calculated in this way is stored in a computer (not shown) via a resolver digital converter (hereinafter, an R / D converter). Similarly, the rotation angle θ of the output side cylindrical rotor 2 is also output from the output side resolver mechanism R2.
2. Detect and enter it into the above computer. The computer calculates the relative angle Δθ between the input side and the output side as Δθ = θ1−θ2, and calculates the torque from the relative angle Δθ that is the torsion angle of the torsion bar 1 and the rigidity of the torsion bar 1. calculate.

[0009] The conventional device as described above requires a resolver mechanism and an R / D converter on both the input side and the output side. Then, since Δθ is calculated by using signals obtained from the two sets of resolver mechanisms and the torque is detected, there is a problem that the apparatus becomes expensive accordingly. Further, as described above, an arithmetic circuit for calculating Δθ and a wiring structure for arranging them are required, so that the space for incorporating them must be increased, and the entire device becomes larger or more expensive. There was a problem.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque measuring device which has a simple structure and can be reduced in size and cost.

[0011]

The above object is achieved by the following constitution. (1) An input-side rotor (2) and an output-side rotor (4) arranged rotatably in the circumferential direction, and a relative twist between the input-side rotor (2) and the output-side rotor (4). A torsion amount measuring device for detecting an amount, comprising an input-side stator (1) at a predetermined interval at a position facing the input-side rotor (2) in a circumferential direction, and the output-side rotor (4).
An output-side stator (3) is provided at a predetermined interval at a position opposed to the output-side stator (3). , 6) wherein the output winding of the input-side stator (1) and the output winding of the output-side stator (3) are interconnected. (2) The torsion amount measuring device according to (1), wherein an excitation signal is input to an excitation winding of the input-side stator (1) and an output signal is obtained from the excitation winding of the output-side stator (3). (3) The output windings of the input-side stator (1) and the output windings of the output-side stator (3) have windings of a plurality of phases, and the windings of the same phase are mutually connected. 1)
Or the torsion amount measuring device of (2). (4) The torsion amount measuring device according to any one of (1) to (3), wherein the output signal is synchronously rectified to be a signal representing the amount of torsion. (5) The torsion amount measuring device according to any one of (1) to (4), further including a magnetic shielding means (9) between at least the input side stator (1) and the output side stator (3).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The torsion measuring apparatus of the present invention has an input rotor 2 and an output rotor 4 which are rotatably arranged on the same axis in the circumferential direction as shown in FIG. And
A torsion amount measuring device for detecting a relative amount of torsion between the input side rotor 2 and the output side rotor 4, wherein the input side stator 1 is disposed at a predetermined interval at a position facing the input side rotor 2 in the circumferential direction. An output stator 3 is provided at a predetermined interval at a position facing the output rotor 4 in the circumferential direction, and the input stator 1 and the output stator 3 are respectively provided with an excitation winding and an output winding. 5 and 6, and the output winding of the input side stator 1 and the output winding of the output side stator 3 are connected to each other.

An excitation signal is input to the excitation winding of the input-side stator, and an output signal is obtained from the excitation winding of the output-side stator.

Preferably, the output winding of the input-side stator and the output winding of the output-side stator have a plurality of phase windings, and the windings of the same phase are mutually connected.

Referring to FIG. 1 in more detail, a resolver as a torsion measuring device has an input-side rotor 2 and an output-side rotor 4 which are rotatably arranged on the same axis in the circumferential direction. A rotating body (not shown) for detecting the amount of twist is connected to the input rotor 2 and the output rotor 4. The rotating body is not particularly limited as long as one of the rotating bodies has a displacement amount (rotation amount) relatively different from the other.
The angle is preferably within 45 °, particularly about ± 0 to 22.5 °.

Each of the rotors 2 and 4 is a deformed cylindrical or disk-shaped magnetic material, and the gap between the outer surface thereof and each of the magnetic poles of the stators 1 and 3 is changed by the rotation operation, so that the exciting winding and the output winding are changed. The line is formed so that an output signal corresponding to the amount of rotational displacement can be obtained. This shape may be a disk-shaped or cylindrical rotating body whose center axis is shifted from the center axis of the stator, but as will be described later, in order to remove harmonic distortion, the shape is determined by a predetermined number of poles. It is preferable that the outer periphery has a shape having a projection with a special curve.

The preferred shapes of the rotors 2 and 4 will be described. As the shape of the rotors 2 and 4, a method of determining the shape of the rotor of a normal variable reluctance resolver can be used.
Use the method described in the above item.

In a structure in which the rotors 2 and 4 are made of a magnetic material having N salient poles and are not provided with a winding, the rotor is driven by the action of the magnetomotive force generated by the current of the exciting winding and the variation in gap permeance due to the salient poles. When moving 1 / N of the entire circumference, the spatial position of the peak value of the magnetic flux density utilizes the movement of 1 / N of the entire circumference.

The induced voltage to the output winding due to the magnetic flux density is 1 / N of the entire circumference of the rotor when the excitation winding is single-phase and the output winding is two-phase or three-phase. , A two-phase or three-phase voltage having a sinusoidal waveform with one cycle, and when the excitation winding is two-phase and the output winding is single-phase, when the rotor moves 1 / N of the entire circumference, the amplitude becomes One cycle (electric angle 2π)
The result is a varying sinusoidal voltage. The relationship between these voltages and the rotor position is the same as that of a resolver or a synchro currently used.

In this method, it is important to minimize harmonic components contained in the induced voltage of the output winding, which cause an error. In the present invention, the variation of the gap permeance coefficient due to the N salient poles due to the rotor position θ ₂ is co.
This can be realized by forming a salient pole shape having a value proportional to s (Nθ) and having a very small harmonic component therewith.

An input stator 1 is provided at a predetermined distance from the input rotor 2 in a circumferential direction, and a predetermined distance is provided at a position opposite to the output rotor 4 in the circumferential direction. And an input side stator 3. These stators 1 and 3 are fixed to a resolver case 7.

Each of the stators 1 and 3 is a hollow annular magnetic body, and has a plurality of magnetic poles protruding in the axial center direction thereof.
It has a configuration having a slot around which a winding is wound between these magnetic poles.

An excitation winding and output windings 5 and 6 are wound around the magnetic poles of such a stator. The excitation winding is a winding for generating a magnetic field, and the output winding is a winding for extracting an excitation voltage generated by the excitation winding and excited by a magnetic field that is changed by the rotational movement of the rotor. It is preferable that the output winding be a distributed winding so that the generated induced voltage distribution becomes a sine wave distribution.

Further, as shown in FIG. 6, for example, it is preferable to have magnetic shielding means 9 so that the output side output winding is not directly electromagnetically induced by the excitation signal of the input side stator. The magnetic shielding means is not particularly limited as long as it can shield the magnetism. For example, a shielding plate made of a magnetic material may be provided. The other configurations in FIG. 6 are the same as those in FIG. 1, and the same components are denoted by the same reference numerals and description thereof will be omitted.

As described above, the input-side rotor 2 and the input-side stator 1 form an input-side resolver, and the output-side rotor 4 and the output-side stator 3 form an output-side resolver. With these two resolvers, the displacement amount on the input side and the output side can be detected as an electric signal.

In the present invention, the output winding of the input-side stator and the output winding of the output-side stator are connected to each other. Specifically, for example, as shown in FIG. 2, the excitation winding 5 a and the output windings 5 b and 5 c are wound around the input side stator 1,
The stator 3 on the output side has an exciting winding 6 a and an output winding 6.
b, 6c are wound.

In this example, among the two-phase output windings, terminals S1 and S2 of the input-side first-phase output winding 5b,
The terminals S11 and S12 of the output-side first-phase output winding 6b are respectively connected. Similarly, the output winding 5c of the input-side second phase
Are connected to the terminals S3 and S4 of the output winding 6c of the output-side second phase, respectively. By connecting the output windings to each other in this manner, when an input signal ERI is applied between the terminals R1 and R2 of the input-side excitation winding 5a, the connection between the terminals R11 and R12 of the output-side excitation winding 6a is established. Shows an output signal ERo represented by the following equation.

That is, when the input signal ERI = Esinωt of the following equation is given between the terminals S1 and S2, the voltage between the terminals S1-2 and S3-4 of the output windings 5b and 5c is changed according to the displacement φ on the input side. ES1-2 = KiEsinωt · cos (X · φ) ES3-4 = KiEsinωt · sin (X · φ) And this is the terminal S of the output windings 6b and 6c.
11-12 and S13-14, the output voltage ERo = Kosinωt · sinX (φ−) is applied between the terminals R11 and R12 of the output-side exciting winding 6a in accordance with the output-side displacement amount θ. θ) (Ki, Ko: transformation ratio, X: shaft double angle (X = 1 to 8, especially 2 to 8)) are obtained.

The obtained output waveform is the excitation signal Esin ωt
Is superimposed, and a signal corresponding to the displacement angle, that is, the amount of twist, KsinX (φ−θ) is removed by removing the excitation signal component which is superimposed by a detection circuit, a rectifier circuit, and the like. Ratio (coefficient)] is obtained.

In the present invention, it is preferable to extract and use only a linear region from the obtained signal. That is, the torsion amount measuring apparatus of the present invention does not need to measure 360 ° full angle of the rotation amount, and if it is a normal steering,
It is sufficient if the displacement angle can be measured within ± 20 °, preferably ± 15 °. For this reason, if the linear region of the obtained output signal sinX (φ−θ) is within the measurement angle, the displacement (torsion) can be replaced with a linear signal.

[0031]

Next, a preferred embodiment of the present invention will be described with reference to the drawings. The torsion amount measuring device shown in FIG. 3 shows an example of measuring the torsion amount of a torsion bar in power steering of a vehicle.

In the figure, an input shaft and an output shaft of a torsion bar 13 are connected to an input rotor 2 and an output rotor 4, respectively. Other configurations are the same as those of the measuring apparatus shown in FIG. 1, and the same components are denoted by the same reference numerals and description thereof will be omitted. The two resolvers are housed in a housing case 8. In this example, the shaft double angle X
Was set to 4.

In the torsion amount measuring device having such a configuration, the excitation input voltage Esi is applied to the input-side excitation inputs R1 and R2.
When nωt is given, a signal ERo = Kosinωt · sin4 (φ−θ) corresponding to the twist angle is output.

The obtained output signal is a single output, and the output signal line can be taken out by a pair of signal lines corresponding to R11-R12. For this reason, the signal lines, which were conventionally required eight,
It is less than half, and the reliability is more than doubled.

Next, the obtained output signal ERo was applied to an input terminal IN1 of a synchronous rectifier circuit as shown in FIG. This synchronous rectifier circuit includes an amplifier circuit including two operational amplifiers OP1 and OP2 and resistors R1 to R5, and an analog switch SW that switches the output of the amplifier circuit in a time-division manner. Then, the operational amplifier OP3 and the capacitor C
1. High frequency components are removed from the output of the analog switch SW by a low pass filter composed of resistors R7 and R8. The excitation signal Esinωt input to the other input terminal IN2 is supplied to the comparator OP4 and the resistor R
The signal is converted into a rectangular signal by a comparator circuit composed of 6, 9, and 10, and the analog switch SW is driven.

Thus, the excitation signal component E given to the other input terminal IN2 is obtained from the signal Kosinωt · sin4 (φ−θ) input to the input terminal IN1.
The sinωt is removed by an analog switch synchronized with this signal, and the high-frequency component is further removed, and Ksin4 (φ−θ) is obtained at the output terminal OUT. FIG. 5 shows the obtained output signal.

The region indicated by R in the figure is a linear region, and this region ± r is preferably within ± 22.5 °, more preferably within ± 20 °. When the torsion measuring apparatus of the present invention is used for normal steering control, ± 10
Measuring the displacement angle within ° is sufficient. Therefore, by using the signal in the linear region, RD for performing A / D conversion
It can be seen that a linear signal corresponding to the displacement can be obtained with a synchronous rectifier circuit combining an inexpensive operational amplifier and a comparator without using a converter, and the number of wirings can be reduced to １ ／.

That is, there is no need to calculate Δθ from the two signal waveforms, no arithmetic circuit is required, and the number of wirings is reduced, so that the cost can be significantly reduced as compared with the conventional device. In addition, the fact that the number of parts attached to the resolver can be reduced means that the entire device can be reduced in size, can be used in a place where the installation space is small, and the cost can be reduced as a whole. In addition, the number of components, particularly the number of wirings, is reduced, so that the reliability is improved. Therefore, the manufacture of the resolver mechanism becomes extremely simple.

[0039]

As described above, according to the torsion amount measuring apparatus of the present invention, it is possible to provide a torque measuring apparatus which has a simple structure and can be reduced in size and cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a torsion measuring apparatus according to the present invention.

FIG. 2 is a circuit diagram of an excitation winding and an output winding of FIG.

FIG. 3 is a sectional view of a main part of the embodiment.

FIG. 4 is a circuit diagram illustrating an example of a synchronous rectifier circuit.

FIG. 5 is an output voltage characteristic diagram of the circuit of FIG. 4;

FIG. 6 is a sectional view showing another configuration example of the torsion amount measuring device.

FIG. 7 is a schematic view of a conventional device.

FIG. 8 is a sectional view of a resolver mechanism.

FIG. 9 is a circuit diagram.

FIG. 10 is an output voltage characteristic diagram.

[Explanation of symbols]

 1,3 stator 2,4 rotor 5,6 output winding

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01L 3/10 G01L 3/10 Z 5/22 5/22 H02K 24/00 H02K 24/00 F term (reference) ) 2F051 AA01 AB05 BA03 2F063 AA34 BA08 CA34 CA40 DA05 DD03 EA03 GA22 KA01 KA02 LA30 2F077 AA21 AA43 FF03 FF13 FF34 FF39 TT21 TT82 UU26 3D033 CA28 DB05

Claims (5)

[Claims] An input-side rotor (2) and an output-side rotor (4) are disposed so as to be rotatable in a circumferential direction, and the input-side rotor (2) and the output-side rotor (4) are connected to each other. A torsion amount measuring device for detecting a relative torsion amount, comprising: an input side stator (1) at a predetermined interval at a position circumferentially opposed to the input side rotor (2); An output side stator (3) is provided at a predetermined interval at a position opposed to 4) in the circumferential direction, and the input side stator (1) and the output side stator (3)
The amount of torsion having an exciting winding and an output winding (5, 6), respectively, and the output winding of the input-side stator (1) and the output winding of the output-side stator (3) being mutually connected. measuring device. 2. The torsion measuring apparatus according to claim 1, wherein an excitation signal is input to an excitation winding of the input-side stator, and an output signal is obtained from the excitation winding of the output-side stator. 3. An output winding of the input-side stator (1) and an output winding of the output-side stator (3) have a multi-phase winding, and the windings of the same phase are connected to each other. The torsion amount measuring device according to claim 1 or 2. 4. The torsion amount measuring device according to claim 1, wherein the output signal is synchronously rectified to be a signal representing a torsion amount. 5. A magnetic shielding means (9) between at least the input side stator (1) and the output side stator (3).
The torsion amount measuring device according to any one of claims 1 to 4, further comprising: