JPS63172933A - Phase difference type torque detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for detecting the amount of torque generated on a rotating shaft of a vehicle, and particularly relates to a device for detecting the amount of torque generated on a rotating shaft of a vehicle, and in particular, a phase difference type torque detection device using a magnetic gear and a rotational position detector. This invention relates to a detection device.

[Conventional technology]

The conventional phase difference type torque detection device is disclosed in Japanese Patent Application Laid-Open No. 60-220.
As described in Publication No. 834, in two magnetoresistive element type rotational position detectors that each detect the rotational position state of two gears mounted on a rotating shaft at regular intervals, the resistance changes depending on the direction of the magnetic lines of force. A magnetoresistive element whose value changes is placed at the tip of the rotational position detector, and the tooth tip and tooth bottom of the gear facing the magnetoresistive element are detected in a non-contact manner. The output signals of the two rotational position detectors are independent of the rotational speed.
Torque detection has been performed on the premise that the output signal is always a sine wave signal and that the reference voltage of the comparison circuit when shaping the output signal into a pulse signal is at a zero cross level.

[Problem that the invention seeks to solve]

The conventional phase-difference torque detection device described above does not take into account the case where the output signal of the rotational position detector is distorted depending on the rotational speed of the gear.

That is, during rotation of the gear, the output signal of the rotational position detector is 'I!' generated within the tip of the rotational position detector opposite to the tooth tip of the gear. If the distortion occurs due to the influence of the magnetic field caused by the current, it will directly affect the duty ratio of the pulse signal when converting the output signal of the one-rotation position detector into a pulse signal.
This was a cause of error in torque amount.

Further consideration of this point shows that when the tip of the rotational position detector is made of a metal member, the eddy current increases within the metal member in proportion to the rotational speed of the rotating shaft. The magnetic flux generated by the magnet in the position sensor changes during one rotation when the time rate of change of the magnetic flux generated by the magnet in the position detector is greatest, that is, when it changes from the bottom of the gear tooth to the tip of the tooth, and vice versa. When this happens, the output signal of the magnetoresistive element in the rotational position detector becomes a distorted waveform due to the effect of the magnetic flux generated by the eddy current, which also acts most strongly. As a result, even if the output signal of the magnetoresistive element is waveform-shaped into a pulse signal, the duty ratio of the pulse signal, which is related to the accuracy of the torque amount, changes, making it impossible to accurately detect the torque amount.

An object of the present invention is to provide a phase difference type torque detection device that can accurately detect torque without being affected by the rotation speed of a rotating shaft.

[Means for solving problems]

In order to achieve the above object, the present invention is characterized in that the tip of the one-rotation position detector is made of an insulating material.

[Effect]

The phase difference type torque detection device according to the present invention eliminates the generation of the above-mentioned eddy current by replacing the metal member at the tip of the one-rotation position detector with an insulating member.

Since waveform distortion of the output signal of the magnetoresistive element can be eliminated, the amount of torque can be detected with high accuracy.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure is a system configuration diagram of a phase difference type torque detection device. A rotating shaft 6 for transmitting power is provided in the casing 1 of the power transmitting unit of a vehicle, and two gears 4.5 having the same number of teeth are attached to the rotating shaft 6 at a certain distance. In close proximity.

Two magnetoresistive rotational position detectors 2 and 3 are mounted on the casing 1 and are adapted to detect the rotational states of the gears 4 and 5, respectively. The output signals of the rotational position detectors 2 and 3 are converted into pulse signals via waveform shaping circuits 7 and 8. Next, the on-duty ratio of the phase difference signal between the output signals of the rotational position detector 2.3 which is proportional to the amount of torque applied to the rotating wheel 6 is detected. Input 2 and 3 output signals respectively.

Here, the phase difference signal detection circuit 10 will be explained using FIGS. 4 and 5. The input pulse signal 80.81 at the input terminal 27.28 of the phase difference detection circuit 10 is input to a differentiating circuit 70.71 consisting of a capacitor and a resistor, and then is converted into a differentiated signal 82. .

Signal 84.85 is obtained by clamping the negative component of 83 with diode 72.73.

The signals 84, 85 are input to the flip-flop circuit 74, and as a result, a phase difference signal 86 between the pulse signals 80, 81 can be obtained.

Next, the output signal of the phase difference signal detection circuit 10 is
In order to count the ON time of the 0 output signal, the reference time generation circuit 23. The signal is inputted to a microcomputer (hereinafter simply referred to as microcomputer) 24 via a gate circuit 12.degree. 14 and a counter 16.

In order to detect the period of the phase difference signal, first, the output of the waveform shaping circuit 7 is frequency-divided by 172 in the frequency dividing circuit 9, and then the reference time generating circuit 23...
The signal is input to the microcomputer 24 via the gate circuits 11 and 13 and the counter 15. As described above, the on-duty ratio of the phase difference signal is determined within the microcomputer 24, that is,
Calculate on time/period. In other words, the on-duty ratio of the phase difference signal between the output signals of the two rotational position detectors 2゜3 changes in proportion to the amount of torque generated on the one-rotation shaft 6. The amount of torque generated at 6 can be detected. The tarlage sensor 75 detects whether the rotating shaft 6 is loaded or unloaded by detecting when the clutch is engaged or disengaged, and the details will be described later.

Next, the structure of the two rotational position detectors 2 and 3 will be explained with reference to FIG. A magnetoresistive element (hereinafter abbreviated as MRE) 33 whose resistance value changes depending on the direction of magnetic lines of force is connected to the rotational position detector 2.
, placed at the tip of 3.

The tooth tips and tooth bottoms of the gear 43 are detected in a non-contact manner. A permanent magnet 35 that is integrated with an iron core 36 is provided at the rear of the MRE 33 .

Therefore, the magnetic field lines 38 generated from the permanent magnet 35 are MR
From E33 to gap 44 → gear 43 → gap 44 → core 3
6 → flows to magnet 35.

The direction of these magnetic lines of force 38 changes within the MRE 33 as the tooth tips 39, 40 and tooth bottoms 41, 42 of the gear 43 facing the MRE 33 alternately change. This changes the resistance value within the MRE 33, and since the resistor within the MRE 33 has three terminals, when a voltage is applied between two terminals, a voltage signal can be obtained from the remaining intermediate terminal.

The three terminals (electrical voltage, ground, voltage signal) are connected to three external lead wires 37 via three lead wires 34, respectively, and these MRE 33, magnet 35, core 36. The lead wire 34 is covered by a housing portion 32 made of a non-magnetic material.

Further, the rotational position detectors 2 and 3 are attached to the casing 1 by threaded portions 31 formed in the housing portion 32.

A hole is formed at the tip of the housing portion 32, and the inside of this hole is covered with an insulating member 45 made of synthetic resin or the like.

Hereinafter, the action of this resin part will be explained with reference to the time chart shown in FIG.

First, the output signal 50 of the MRE in the rotational position detectors 2 and 3 when the rotary shaft 6 is rotating at a low rotation speed under no load.
．． 53 are as shown in the figure.

This output signal 50.53 is converted into a pulse signal 62.63 of the waveform shaping circuits 7 and 8. In this case, it is difficult to completely set the reference voltage level 51.60 of the comparators in the waveform shaping circuits 7 and 8 to the zero cross level 52.61 due to the influence of the input bias current, so It deviates from the zero cross level of 52.61.

Next, when the one-rotation shaft 6 rotates at a high rotation speed, eddy currents, which were not a problem at low rotation speeds, become a problem. That is, when the tips of the rotational position detectors 2 and 3 are made of metal members, eddy currents become large at the metal members at the tips, and in particular, the lines of magnetic force generated by these eddy currents are Tooth tip 39.40 and tooth bottom 41 where the generated magnetic lines of force 38 have the largest rate of change over time
At an angle of 42°, it acts most strongly in the direction opposite to the magnetic field lines 38. Therefore, the output signal of the MRE 33 becomes a distorted waveform signal 54 in which the signal 55 is superimposed on the signal 53 due to the influence of the magnetic lines of force generated by the eddy current.

Here, the positional relationship between the signal 55 due to the eddy current component and the gear is as follows. The tooth tip portion 39 where the time rate of change in magnetic flux changes from large to small is at point A, the tooth tip portion 40 where the time rate of change in magnetic flux changes from small to large is at point B, and the tooth where the time rate of change in magnetic flux changes from large to small. The bottom portion 41 is point 0, and the tooth bottom portion 42 where the rate of change of magnetic flux changes from small to large over time is point D.

The signal 54 becomes the signal 64 after waveform shaping, and the on-duty ratio D (in the case of 63, D = t 1
/ T Cxv a) + 64, then D = t
Although s/D a) hardly changes, the phase difference signal 65 proportional to the amount of torque shows the signal 66, which shows that when the rotation speed is increased under no load, torque is apparently generated on the shaft 6 for one revolution. corresponds to In other words, the difference in the on-duty ratio of the phase difference signal (ti/T) (ta/T
) is the apparent torque amount. Therefore, in order to eliminate this apparent torque, a portion of the tip of the rotational position detector is constructed with an insulating member 45 to eliminate eddy currents.

Rotational position detectors 2 and 3 obtained by the above method
A method of calculating the torque value applied to the rotary shaft 6 using the output signal and the phase difference signal will be explained with reference to the flowchart in FIG.

First, in step 90, the input/output ports of the microcomputer 24 are initialized, step 91 is a phase difference signal measurement routine under no load, and step 92 is a phase difference signal measurement routine under load. First, the routine of step 91 will be explained. In step 93, a clutch engagement determination is performed; that is, when the clutch is disengaged, the rotating shaft is considered to be under no load, whereas when the clutch is engaged, the rotating shaft is considered to be in a state in which a load can be generated.

Therefore, only when it is determined in step 93 that the clutch is disengaging, the next step 94 is advanced. value and the on time t4 of the one phase difference signal 65
The value of the measurement counter 16 is input to the microcomputer 24. In step 95, a phase difference signal 6 is obtained from the input values T(1) and t4.
Calculate the on-duty ratio D = 't g / T of 5. This on-duty ratio means the reference value of torque under no load.

Next, the routine of step 92 will be explained. Step 9
In step 6, contrary to the process in step 93, the process advances to the next step 97 only when it is determined that the clutch is engaged, and the processes in steps 97 and 98 are performed in the same manner as in steps 94 and 95 to determine the on-duty condition under load. Ratio D' ta /T
' Calculate. In step 99, steps 95 and 98
Difference ΔD between the on-duty ratio and D′ calculated for each
Finally, the torque value T applied to the rotation shaft 6 is determined by the following equation. In the formula below, G is the transverse elastic modulus, Z is the number of gear teeth, d is the rotating shaft diameter between the gears, Q is the distance between the gears, π
is pi.

Next, there is a possibility that the reference torque value under no load may change due to fluctuations in the residual torque of the rotating shaft or changes in the rotational position detectors 2 and 3 over time. In order to cope with this, in step 100, the reference value of the torque under load is updated every fixed time period TΔ.

Through the above processing, the amount of torque applied to the rotating shaft 6 can be detected.

〔Effect of the invention〕

As explained above, according to the present invention, since the tip of the rotational position detector is made of an insulating material, the torque amount can be detected with high accuracy without being affected by the rotation speed of the single rotation shaft. There is.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a phase difference torque detection device according to an embodiment of the present invention, FIG. 2 is a structural diagram of the rotational position detector of FIG. 1, and FIG. 3 is a time chart of each signal. Fourth
This figure is a block diagram of the phase difference signal detection circuit of FIG. 1, FIG. 5 is a time chart of each signal of FIG. 4, and FIG. 6 is a broach yard of the torque calculation method. 2.3... Rotational position detector, 4, 5... Magnetic gear, 6... Rotating shaft, 7, 8... Waveform shaping circuit, 10.
...Phase difference signal detection circuit, 15.16...Counter, 2
3...Reference time generation circuit, 24...Microcomputer.

Claims (1)

[Scope of Claims] 1. Two magnetic gears attached to the rotating shaft of the vehicle at regular intervals; and 2, each attached close to the outer periphery of the two gears to detect the rotational state of the two gears. a waveform shaping circuit that shapes the output signals of the two rotational position detectors into pulse signals, and a phase difference signal detection circuit that detects a phase difference signal between the pulse signals. a reference time generation circuit and a counter that measure the time when the period of the pulse signal and the voltage level of the phase difference signal are high;
In a phase difference torque detection device comprising a microcomputer that performs arithmetic processing on the output signal of the counter to calculate torque, the tip of the rotational position detector mounted opposite to the outer periphery of the gear is made of an insulating material. A phase difference type torque detection device characterized by comprising: 2. The phase difference type torque detection device according to claim 1, wherein the rotational position detector is composed of a magnetic resistance element and a magnet. 3. The phase difference torque detection device according to claim 1, wherein the insulating material at the tip of the rotational position detector is made of synthetic resin.