JPH0996579A - Axle dynamometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the component of force acting on an axle and a tire accurately and reliably in the mounted state on a vehicle by providing an initial adjusting mode function, which automatically performs the initial adjustment before performing a main measuring mode and completes the excecution preparation of the main measuring mode after a specified number of rotation of the axle. SOLUTION: The signal of the component of force from a multiple component-of- force detector 4, which is fixed and mounted between an axle 1 and a wheel 5 having a tire 13, is sent to a slip ring 9 housed in a detecting part 7. The turning angle of the axle 1 is measured with a turning angle meter 8. The turning angle from the detecting part 7 and the detected signal of the component of force are sent into an operating part. The signal of the component of force in the rotating coordinate system, which is rotated together with the axle 1, is converted into the signal of the component of force in the fixed coordinate system fixed to a vehicle body. Then, the operating part automatically performs the initial adjustment of the entire measuring system and excecutes the initial adjustment mode, which completes the excecution preparation of the main measuring mode, after the axle is rotated by a specified number. When the initial adjustment mode is finished, the main measuring mode is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle dynamometer for measuring a component force acting between a vehicle axle and a tire.

[0002]

BACKGROUND OF THE INVENTION Axle dynamometers of this type are used in various road conditions, such as paved ideal roads, gravel roads, rainy wet roads, etc., and in various driving conditions, for example at steady speeds. When traveling, measuring the force and / or moment acting between the axle and the tire during sudden start, sudden stop, or cornering gives extremely important knowledge to the basic design of an automobile. In this regard, the present applicant has already proposed in JP-A-62-87823. Axle dynamometers used for similar purposes are RS Shonberg & B. Walla
c: Automotive Engeneering Congress and Exposition,
Detroit, Michigan, Feb. 24-28, 1975 (Society of Au
tomotive Engeneerings INC.), and CA Lysdale
& RR Hegmon, "Development of a Truck Wheel Forc
eTransducer ", Society of Automotive Engeneerings I
NC. Feb. 25-29, 1980.

In these axle dynamometers, in order to measure the component force acting between the axle and the tire, a multi-component force detector is mounted between them. Therefore, the measurement result is obtained as the component force value in the rotating coordinate system that rotates in synchronization with the tire, and is different from the component force value of the stationary system felt by the person inside the vehicle. To convert a rotating system to a stationary system, it is necessary to first be able to continuously measure the rotation angle of the axle and to use this rotation angle to execute a conversion formula that converts the rotating system to a stationary system in real time. is there.

RS Shonberg et al. And CA Lysdale
In axle dynamometers such as the above, a resolver and a potentiometer for generating trigonometric functions (sine and cosine signals) are used to measure the rotation angle, and analog signal processing is performed. On the contrary, in the axle dynamometer disclosed in Japanese Patent Laid-Open No. 62-87823, the rotary angle is photoelectrically measured by using the rotary encoder, so that the angular position of the axle at that time is extremely accurately measured without any disturbance. Can be measured. The conversion of the measured values between the stationary system and the rotating system can be performed digitally. Since the axle dynamometer is used while the vehicle is running, it is subject to strong mechanical and electrical disturbances due to severe vibration and braking, and spark discharge at the time of plug ignition. In the resolver, the current of a specific carrier frequency generated in the oscillator circuit is applied to the coil of the rotor and rotated in the stator to measure the rotation angle based on the principle of the generator. It requires a lot of circuit consideration and cost. Further, when the potentiometer as described above is used, the contact of the slider contacting the resistance wire and / or the resistance wire itself is abraded, resulting in a very short life.

When using an axle dynamometer, the most cumbersome task is initial adjustment. For example, each component force, that is, the forces F _X, F _Y, F _{Z in the} directions of the three orthogonal axes and the moments (torques) M _X, M _Y, M _Z about the three orthogonal axes are set to zero points of the signal processing path extending to 6 channels. Each needs to be adjusted independently. The deviation of the actual value to be obtained from the raw data of the multi-component force detector has various causes such as the actual load of the vehicle, the mounting condition of the axle dynamometer, and the inherent performance of the multi-component force detector itself. If the six kinds of zero adjustment are individually performed, it takes time, and the original measurement efficiency is significantly reduced.

Further, in order to mount the axle dynamometer on an actual vehicle, it is necessary to have a suitable mechanical strength, and it is necessary to guarantee earthquake resistance, humidity resistance and electromagnetic induction resistance. However, in order to satisfy these requirements, there is a problem that the axle dynamometer including the auxiliary members around the force detector must be designed to have a sturdy and complicated structure.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to guarantee the required mechanical strength with a simple structure, and nevertheless perform initial adjustment easily and automatically when mounted on a vehicle. An object of the present invention is to provide an axle dynamometer capable of obtaining accurate and reliable measurement results regarding the component force acting between the axle and the tire.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned problem is solved by a multi-component force detector 4 fixedly mounted between an axle 1 and a wheel 5 with a tire 13, and a multi-component force detector via a bearing 14. 4 is connected to the vehicle body by stopping rotation,
A rotation angle meter 8 for measuring the rotation angle of the axle 1 and a detection section 7 having a slip ring 9 for transmitting a component force signal of the multi-component force detector 4 in the detection section 7, and a cable 1
Using the detection signals of the rotation angle and the component force introduced from the detection unit 7 via 2, the component signal of the rotating coordinate system rotating with the axle 1 is converted into the component signal of the fixed coordinate system fixed to the vehicle body. In an axle dynamometer equipped with an arithmetic processing unit, the arithmetic processing unit automatically performs an initial measurement of the measurement system before the main measurement mode function for executing the original measurement. This is solved by the provision of an initial adjustment mode function that completes the preparations for execution of the main measurement mode after performing a predetermined number of rotations of the axle.

Further advantageous configurations according to the invention are described in the dependent claims.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In an axle dynamometer, in order to measure a component force acting between a tire and an axle to which the tire is attached,
Probably equipped with a force detector between the tire and the axle. Therefore,
In a steady running state, a periodic component force (sine wave component component) is generated in the multi-component force detector in synchronization with the rotation of the axle. The traveling direction of the vehicle is the X direction, and the vertical direction is the Z direction.
When a coordinate system such as that described above is introduced, the main component force acting between the tire and the axle is due to the weight of the vehicle facing in the Z direction. Therefore, in a steady running state, when the detection output of the multi-component force detector is converted into a stationary system (the same coordinate system as the vehicle), a constant component force is working.

If the roadway is uneven or there is a change in the running condition (for example, when braking or traveling on a curve),
A complex component force is generated between the tire and the axle due to the equilibrium state of the inertial force due to the acceleration and angular acceleration of the vehicle including the suspension spring characteristic of the axle and the equivalent spring characteristic of the tire itself and the restraining force due to the ground. It is desirable to find these component forces not in the rotating system but in the stationary system.

Component force F of the rotary system obtained by the multi-component force detector
_{From X} ', F _Y ' _, F _Z ' _, M _X ' _, M _Y ' _, M _Z ', the component force F _X, F of the static system
_In order to obtain _Y, F _Z, M _X, M _Y, M _Z , in the case of the arrangement shown in FIG.
No. -87823). F _X = F _X 'cos θ-F _Z ' sin θ F _Y = F _Y 'F _Z = F _X ' sin θ + F _Z 'cos θ (1) M _X = M _X ' cos θ-M _Z 'sin θ M _Y = M _Y ' M _Z = M _X 'sin θ + M _Z ' cos θ An incremental rotary encoder is used to measure the rotation angle θ. That is, the rotation angle θ is obtained by reading the scale of the scale disk fixedly connected to the axle with a photoelectric reader equipped in the stationary system (vehicle body).

In the axle dynamometer according to the present invention, the following corrections are made to the raw measurement values obtained by the multi-component force detector after the rotation / stationary system conversion as described above. (a) Correction for the mismatch between the reference plane of the force detector and the center plane of the wheel position. Let L be the distance between the reference plane (one flange face) of the force detector and the center plane of the wheel in the axial direction. , L will be referred to as the action interval hereinafter. Considering this action interval, the moments about the X and Z axes are corrected by the following relational expressions.

M _X = M _X ′ + F _Z ′ · L M _Z = M _Z ′ −F _X ′ · L (2) Here, M _X and M _Z are moments to be calculated, and M _X ′,
M _Z ′, F _X ′ and F _Z ′ are component forces converted into a rotating system by the equation (1). For the conversion, refer to the specification of Japanese Utility Model Application Laid-Open No. 3-115830 already proposed by the present applicant.

(B) Automatic correction for detecting and offsetting offset value of multi-component force detector The output of the signal processing channel of each component force is measured once under the measurement condition, and its average value (integrated over one rotation of the axle is integrated. )
Is set as the offset level value of the component signal, and this offset level value is subtracted from the signal output and sent to the arithmetic processing unit in the subsequent stage. For the basic principle, refer to Japanese Patent Laid-Open No. 1-61627 proposed by the present applicant.

The actual offset level value of the component signal is
When the vehicle is jacked up, it is due to the weight of the tire and the weight of the wheel.
kg. On the other hand, in the case of tests in which the vehicle is actually driven, the weight conversion value for a passenger car is approximately 400 kg per wheel. (c) Correction of mismatch of angular position between force detector and rotary encoder As mentioned above, since the rotary encoder is an incremental type, absolute angular position cannot be measured, and relative angular position is always given. The Z-phase pulse representing one rotation of the encoder only indicates the relative origin position. In addition, a value deviated from the actual measurement value is also given to the multi-component force detector itself due to the interference phenomenon, and therefore the component force signal value in the rotating coordinate system obtained by subtracting the offset level value after the processing of (b) above is almost It shows a sine waveform, and the intersection with the zero level is generally 0
Considered as °, 90 °, etc. For this reason, there is a deviation between the rotation angle obtained from the detected values of the component force components F _X ' _and F _Z ' which are the most important in the rotation angle conversion, and the angle detected by the rotary encoder. This shift is calculated as follows. Rotary encoder 0, 90, 180, 270, 36
As shown in Fig. 2, the angular position of the zero-crossing point of the detector for both component components corresponding to 0 ° is θ _1, θ _2, θ _3, θ _4, and the deviation for each angle is Δθ _1, Δθ _2, Δθ. _{If 3,} Δθ ₄ , then θ _i = 90 × i + Δθ _i, (i = 1, 2, 3, 4). An appropriate phase shift Δθ _T is Δθ _T = Σ _i Δθ _i / 4 or Σ _i θ _i / 4−135 ° (3). Here, Σ _i means an addition of 1 to 4 for i.

According to the actual measurement, the value of Δθ _T is about 2 °,
In component force detection, an error of about 4% is given. According to the present invention, all the corrections described above are automatically performed in advance as the initial adjustment mode automatically after the axle dynamometer is mounted on the axle of the actual vehicle and before the actual measurement is performed. It

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings showing the preferred embodiments. The detection unit 7 of the axle dynamometer according to the present invention is mounted on a wheel having tires 13, as shown in FIG. In this case, rotation is stopped with respect to the axle by a support device shown by a one-dot chain line, and the vehicle is fixed to the vehicle so as to be capable of expanding and contracting in the lateral direction (X direction) and the vertical direction (Z direction). This support device fixes a support plate O _{1, a} spring-biased laterally expandable guide rail O _{2, an} intermediate piece O _{3, a} spring-biased vertically expandable guide rail O _4, and a detection unit 7. It is composed of a gripping portion O ₅ . The details of this function are already disclosed in the supporting device proposed by the present applicant in Japanese Patent Application Laid-Open No. 3-25305, so refer to it.

FIG. 4 is a schematic cross-sectional view of the entire construction of the axle dynamometer according to the present invention with the detection portion attached to the axle. It should be noted that in this figure, each member is extremely simplified in order to make it easy to explain the names and functions of the required parts, so it is noted that the shapes and arrangement positions of these members are considerably different from the actual ones. I want to. A rim mounting adapter 3 for an axle dynamometer according to the present invention is mounted between a rim 2 of an axle 1 and a wheel 5 having a tire 13 on the outer circumference. A multi-component force detector 4 is fixedly connected to the rim mounting adapter 3, and the multi-component force detector 4 further includes a bearing 14 (this bearing is shown as a thrust bearing, but in reality, as shown in FIG. It is rotatably supported by the detector mounting base 6 of the detector 7 via a bearing. The detection unit 7 is shown in FIG.
As described above, the support device stops the rotation of the axle and is fixed to the vehicle body in a stretchable manner. Detection unit 7
Includes a rotary encoder 8 for measuring the relative position of the rotation angle of the axle 1 with respect to the detector 7 by means of a rotation transmission rod 10 directly connected to the axle 1, and input / output of a multi-component force detector 4 rotating together with the axle 1. A slip ring 9 for electrically connecting the conducting wire to a contact fixed to the detection unit 7 side is built in. The input / output conductor of the rotary encoder 8 and the input / output conductor communicating with the contact point of the slip ring 9 are connected via a cable 12 to an electric circuit (not shown) of the axle dynamometer of the present invention.
It is connected to the.

In FIG. 4, the reference plane of the force detector 4 is at the position A, and the center plane of the wheel 5 is at the position B. The distance between the reference plane A and the center plane B is L as shown. See Eq. (2) for the correction to the detected value when the action intervals of both surfaces have constant values. FIG. 5 shows the details of the essential parts of the detection unit of the axle dynamometer of the invention of this application. Here, in order to improve visibility, connecting bolts and the like between members are deleted from the drawing.
A rim mounting adapter 3 for mounting the detection portion of the axle dynamometer of the invention of this application is mounted on the rim 2 of the axle 1. One flange (fixed flange) 4a of the force detector 4, which is further fixed to the holding block 21 fixed to this rim mounting adapter 3, has four beams 4c (only one is shown) which are the sensing parts. It is fixedly connected to the other flange (measurement flange) 4b via. Furthermore, a wheel 5 is connected to the measuring flange 4b. In order to prevent moisture, mud, muddy water, and smoke from entering the sensitive area 4d of the sensitive area with the strain sensing element, a cover 25 is provided to shut off the outside, and it is hermetically sealed at the required locations. O-ring 1
5a, 15b, 15c are attached.

The fixed block 20 is further connected to the holding block 21 via a bearing 22. As already described with reference to FIG. 3, the fixed cylinder 20 is held by the support member while being prevented from rotating with respect to the rotation of the axle. The rotary encoder 8 is provided inside the fixed cylinder 20.
And the slip ring 9 is attached. One end of the rotation transmission rod 10 connected to the rotary scale disk of the rotary encoder 8 is fixedly connected to the holding block 21, and the other end is fixedly connected to the rotor side of the slip ring 9. According to the present invention, the rotation transmission rod 10 has a hollow central hole 24.
Having. Perhaps a large number of wires (for feeding and detecting) connected to the strain detecting element of the force detector 4 reach the front space 23 from the sensing part space 4d through a hole (not shown) provided in the holding block 21. Further, it reaches the rotor side of the slip ring 9 via the center hole 24 of the rotation transmission rod 10. In the slip ring 9, the electric signal of the lead wire is conductively connected to the stator side fixed to the fixed cylinder 20 via the sliding contact. The detection signal conductor of the strain detecting element, as well as the power supply conductor and the photoelectric detection conductor of the rotary echo unit 8 are connected to the arithmetic processing main body according to the invention of this application through the connector 11 and the cable 12 as shown in FIG.

FIG. 6 shows the general arrangement of the electric system used in the axle dynamometer of the present invention. Here, a case where 6-component force (total component force) is measured will be described. The signals of the bridges A _{1 to} A ₆ composed of the strain gauges of the force detector 4 are probably the first-stage amplifiers V _{1 to} V ₆ (in FIG. 5) fixed to the flange in the sensing part space 4d shown in FIG. (Not shown) and the sliding contacts SR _{1 to} SR ₆ of the slip ring 9 are introduced into the connector 11. Further, the scanning signals (the signals of the A, B and Z phases) from the rotary echo 8 are also directly introduced into the connector 11. In this case, in order to avoid complexity, the feed lines for both are not shown. Maybe force F _X, F _Y, F _Z, M _X, M _Y,
The detection signals S _{1 to} S ₆ corresponding to M _Z and the scanning signals A, B and Z of the rotary echo unit 8 are introduced into the arithmetic processing main body 50 via the connector 11 and the cable 12.

Some operation members of the front panel attached to the arithmetic processing main body 50 have the following functions. (a) Digital switch DS: The dial for displaying the numerical value of the working distance L between the reference plane of the force detector and the center plane of the wheel described above in decimal digits (3 in the case of this embodiment).
This is a switch for inputting a digit and decoding the dial value that has been input and outputting the output signal as a binary digital signal S _L. (b) Display unit IND: a display device (for example, a 4-digit 7-segment LED display device) for displaying each component force or rotation angle value. (c) Zero potential variable resistors R ₁ ^{a to} R ₆ ^a : Variable resistors for varying the offset potential of the final amplification stage of each component channel. (d) Amplification factor changing switch SSW _{1 to} SSW ₆ :
It is a changeover switch for varying the amplification factor of the final amplification stage of each component channel. (e) Rotary switch RS: A switch used for switching to set each component force channel or rotation angle evaluation channel. The output signal of the channel set by the rotary switch RS is displayed on the display unit IND, and the offset potential and the amplification factor of the final amplification stage of the corresponding channel can be changed based on the displayed numerical value. (f) the mode setting switch SW _1, SW _2: Pressing the momentary switch SW ₁ with the initial adjustment mode, the display of that using this mode is carried out by illumination lamps simultaneously for example included. When a predetermined time has elapsed after the vehicle was commissioned (when the axle is rotated several times in the mounted state, the initial adjustment is automatically completed, the illumination display disappears and the preparation for the main measurement is reported. SW ₂ is the main measurement. This is pressed to start, and the attached illumination lamp is emitting light during the main measurement to notify the main measurement mode.

The output signals obtained in each channel and the rotation angle channel are passed through a multi-pin connector CN ₁ to a signal processor or a printer in the subsequent stage, or a high-speed plotter such as an electromagnetic oscillograph (any deviation is not shown).
Connected to The inside of the arithmetic processing body will be further subdivided and described with reference to FIG. 7. Perhaps the force signal channel is processed primarily by analog signals. However,
When a specific analog signal is multiplied by another signal, a digital multiplication method as schematically shown in FIG. 8 is adopted. With respect to the analog input signal S _I , the output signal S ₀ is obtained by appropriately conducting the analog switch S _a connected to each stage of the voltage divider composed of the resistor network to divide the analog switch S _a to a desired value.
Which analog switch S _a is turned on to obtain a desired voltage division is determined by the digital signal S _DIG input as the control signal.
Is determined by the decoder DEC (for the sake of explanation, in FIG. 8, the resistor network is a voltage divider of a resistor circuit that is extremely simplified, but actually, a more complicated ladder resistor network is used. Has been). This kind of calculation can be easily realized with a single digital-analog conversion element on the market. Also, as a matter of course, the resolution of the digital value and the multiplication value is determined by the number of bits of the digital signal S _DIG .

For example, in the equation (2), M _X = M _X '+ F _Z ' .L
, The analog signal S ₃ (F _Z ') and the digital signal S
_L (the digital value of the working interval L) is multiplied, which is performed according to the calculation rule shown in FIG. Then, the desired analog signal S ₁ '(M _X ') is obtained by adding the above-mentioned multiplication value to the analog signal S ₄ (M _X ') in the analog adder. Similar calculation processing can be performed in the same manner for the equation (1).

In the moment correction circuit 52, the operations corresponding to the two equations of equation (2) are executed according to the rules described above, and the input signals S _{1 to} S ₆ are correction signals S ₁ 'to S ₆ '.
Is converted to The output signals A, B, Z from the rotary encoder 8 are introduced into the phase discrimination circuit 57, respectively, where the phase difference between the A-phase pulse and the B-phase pulse (whether one is delayed with respect to the other or is advanced) is detected. In accordance with this, a digital signal indicating up-counting or down-counting and the count value of the A phase (or B phase) are introduced into the reversible counter 58 as a digital output signal δ, and the integrated count value (corresponding to the rotation angle θ ( For example, an 8-bit digital value) is obtained as the digital output signal γ. At that time, the count value is reset by the Z-phase signal indicating one rotation of the scale disk of the rotary encoder 8,
The counting is started again from the first value (angle 0 °). The integrated count value γ is introduced into the ROM storage unit 59, where it is converted into digital values β corresponding to sin θ and cos θ, and introduced into the conversion circuit 54. In the conversion circuit 54,
After subtracting the average value of the component force signals in the initial adjustment mode described below, the component force is converted from the rotating coordinate system to the stationary system according to Eq. (1). As shown and described in the drawings in Japanese Laid-Open Patent Publication No. 62-87823, refer to the specification for details). The integrated count value γ of the reversible counter 58 is further introduced into the digital / analog converter 60, converted into an analog value of the rotation angle θ measured therein, and output to the outside.

The calculation unit 56 is provided with an ordinary microprocessor for performing arithmetic processing, a ROM storage device containing a program of a work sequence, an analog / digital converter, and a digital / analog converter. The following arithmetic processing is performed in the calculation unit 56. That is, when the switch signal S _SW1 corresponding to the initial adjustment mode is input, the analog component force signals S ₁ ′ to S ₆ ′ are converted into digital component force signals by the respective one analog-digital converters attached, so that the axles have a uniform output. While rotating, each digital component force signal is integrated to obtain an average value. That is, for example, a digital mean value C ₂ by averaging the digital frequency output signal C ₁ shown in FIG. 9A
Ask for. This digital average value C ₂ is calculated by the calculation unit 56.
It is stored in a storage device inside and introduced into the conversion circuit 54 as an analog average value C ₂ (α in FIG. 7) by a digital-analog converter. Here, the analog average value C ₂ is subtracted from the corresponding component force signal C ₁ to obtain a signal that fluctuates positively and negatively with a zero value as the center (If this is not done, for example, the component force signal of FIG. In this case, if the subsequent amplification factor is large, the peak value A _1,
The value of A ₂ or the vicinity thereof there is a risk of saturation). Such average value subtraction is performed by calculating the average value of each channel (in FIG. 7, these are simply represented by one analog value α) for all component forces S ₁ 'to S ₆ '. Be seen.

Next, in the initial adjustment mode, the digital meter corresponding to the rotation angle at each zero point of the subtracted values of the analog component force signals S ₁ 'and S ₃ ' introduced into the calculation unit 56. A numerical value γ (digital value corresponding to the rotation angle θ) is obtained (see also FIG. 2). In addition, the angle corresponding to each zero point is calculated assuming that one cycle of the actual analog component force signal is 360 °, and it is set as the digital angle value of the multi-component force detector.
The calculation unit 56 calculates this digital phase difference by obtaining θ _T.
Store it in the designated storage device. RO digital phase difference ε
M is sent to the memory device 59, where γ
Digital angle value β by subtracting the digital phase difference ε from the value
Conversion circuit 5 as (digital value corresponding to θ−Δθ _T )
4, the accurate calculation for the equation (1) is performed, and the component force signals S ₁ ″ to S ₆ ″ of the stationary coordinate system in this measurement mode are obtained.

As is apparent from the above description, the axle dynamometer according to the present invention needs to rotate the axle of the vehicle at least once in the initial adjustment mode. Determine the average signal level from the data of the component force and rotation angle captured by this rotation,
At the next rotation, the difference between the rotation angle of the rotary encoder and the zero position of the force detector is calculated. Of course, it is more advantageous to average the data acquired by rotating the axle several times.

Further, in order to finally amplify the component signals S ₁ ″ to S ₆ ″, the conversion circuit 54 includes final stage amplifiers AMP _{1 to} AMP.
MP ₆ follows. Here, zero-adjustment resistors R _{01 to} R ₀₆ for varying the signal level and three-stage feedback units FBR ₁ to
FBR ₆ (consisting of a feedback resistor and a changeover switch without reference numerals). The changeover switch is shown in FIG.
It is composed of the three-stage changeover switches SSW _{1 to} SSW ₆ described above.

The advantage of such a final stage amplifier will be further described with reference to FIG. The signal waveform S _{A in} FIG. 9B is a component force signal when the vehicle is driven on a relatively flat and ideal roadway at a steady speed. In this case, when checking the ride comfort,
Of particular importance, the high load signal level L _M carries a component that exhibits slight variations. If you want to magnify this fluctuation and examine it, the zero-stage resistance R _{01 of} the final stage amplifiers AMP _{1 to} AMP ₆
The signal level is set to 0 by the level adjustment by R ₀₆ , and the feedback parts FBR _{1 to} FBR ₆ are set to the maximum amplification degree. of course,
When severe stress acts on the tire, such as in a bad road or braking operation, a large fluctuation is added to the signal level L _M as shown by the signal waveform S _{B in} FIG. 9C, and after the zero level adjustment as described above. It is not necessary to increase the amplification rate.

The final signal of the component force and the signal of the rotation angle position are output to the connector CN ₁ , and at the same time, the individual component force signal or the rotation angle position is selectively output to the output end OUT by the selector switch 62 and output. After the signal is converted into a digital value by an appropriate decoder processing, the display unit IN
D is displayed. At that time, the selection of the contact of the selector switch 62 is determined by the selection signal S _SCL of the rotary switch RS.

The main concept of the present invention has been described above.
Omitted for many circuit elements to be added. In particular, the explanation of the use of a filter that selects the pass frequency band of the required signal, the use of a first-stage amplifier that makes it possible to adjust the gain of the component signal taken into the arithmetic processing body by a semi-fixed variable resistor and variable gain is omitted. . Further, the first-stage amplifiers V _{1 to} V ₆ may be arranged, for example, in the arithmetic processing main body 50 after the slip ring 9 instead of being arranged in the sensing section space 4d of the detector. Whatever the deviation, each component signal is mainly analogized in a separate channel and the signal multiplied by the analog signal is carried out with the aid of a digital-to-analog converter. The numerical values and the number of steps used in the description are determined for convenience of description, and the actual numerical values should be selected according to the purpose.

[0034]

As described above, the axle dynamometer of the present invention ensures the required mechanical strength with a simple structure, and nevertheless facilitates initial adjustment when mounted on a vehicle. Moreover, it can be performed automatically, and accurate and reliable measurement results can be obtained regarding the component force acting between the axle and the tire.

[Brief description of drawings]

FIG. 1 is a diagram showing a traveling system of a vehicle and a coordinate system used for an axle dynamometer.

FIG. 2 is a graph showing the relationship between the zero-cross point of the detection signal of the force detector and the rotational angle position of the rotary encoder.

FIG. 3 is a perspective view showing a method of supporting an axle dynamometer.

FIG. 4 is a schematic drawing showing the arrangement of each part of the axle dynamometer.

FIG. 5 is a cross-sectional view showing a main part of a detection unit of an axle dynamometer.

FIG. 6 is a general layout of the electric system of the axle dynamometer.

FIG. 7 is a schematic circuit diagram of a circuit element that multiplies an analog signal by a digital signal.

FIG. 8 is a circuit diagram showing a connection between a processing channel of a force component signal and an auxiliary calculation unit.

FIG. 9 is a graph showing various component signal waveforms.

[Explanation of symbols]

1 axle 2 rim 3 rim mounting adapter 4 maybe force detector 5 wheel 6 detector mount 7 detector 8 rotary encoder 9 slip ring 10 rotation transmission rod 12 cable 13 tire 14 bearing 50 arithmetic processing body 52 moment correction circuit 54 conversion circuit 56 Calculation Circuit 57 Phase Discrimination Circuit 58 Reversible Counter 59 ROM Memory 60 Digital / Analog Converter 62 Selector Switch AMP _{1 to} AMP ₆ Final Amplifier DS Digital Switch IND Numerical Display RS Rotary Switch SW ₁ Initial Adjustment Mode Switch SW ₂ This measurement mode switch S ₁ ~ S _2, S ₁ '~ S ₂ ', S ₁ '' ~ S ₂ '' Component signal

Claims (7)

[Claims] 1. A force detector (4) fixedly mounted between an axle (1) and a wheel (5) with tires (13).
And a rotation angle meter (8) for measuring the rotation angle of the axle (1) and the multi-component force detector (4) which is connected to the vehicle body of the vehicle through a bearing (14) so as to prevent rotation of the multi-component force detector (4). A detector (7) having a slip ring (9) for transmitting the component force signal of the device (4) built in the detector (7);
A fixed coordinate system in which a component signal of a rotating coordinate system that rotates together with the axle (1) is detected by using a detection signal of a rotation angle and a component force introduced from the detection unit (7) via a cable (12) fixed to the vehicle body. In the axle dynamometer provided with an arithmetic processing unit for converting into a component force signal, the arithmetic processing unit has a main measurement mode function for performing an original measurement, and an initial measurement system before the main measurement mode is performed. After making the adjustment automatically and rotating the axle a certain number of times,
An axle dynamometer that is provided with an initial adjustment mode function that completes preparations for execution of this measurement mode. 2. In the initial adjustment mode, the average component value of the corresponding component force of the rotating coordinate system applied to the multiple component force detector (4) due to the weight of the vehicle or the weight of the tire or the wheel from the component force component of the rotating coordinate system is The axle dynamometer according to claim 1, wherein the axle dynamometer is subtracted. 3. In the initial adjustment mode, after subtracting the average component force component of the rotating coordinate system applied to the multi-component force detector (4) from the corresponding component force component of the rotating coordinate system, the rotation angle meter (8) is further added. The phase difference between the indicated angle value of and the indicated angle value of the multi-component force detector (4) is obtained, and the obtained phase difference is stored in a storage device for use in this measurement mode. The axle dynamometer according to claim 2. 4. Correction of the added moments caused by the distance (L) between the center plane (B) of the wheel and the reference plane (A) of the multi-component force detector (4) to the detected component force. The axle dynamometer according to any one of claims 1 to 3, further comprising a function of: 5. In order to prevent noise mixed into the signal of the strain gauge bridge corresponding to each component force, it is fixed to the flange surface near the bridge in the detection space (4d) of the multiple component force detector (4). axle dynamometer according to any one of claims 1 to 4, characterized in that the first-stage amplifier (V ₁ ~V ₆₎ is provided with. 6. A rotation transmission rod (10) of a rotation angle meter (8).
Is directly connected to the axle (1), the rotation angle meter (8) and the slip ring (9) are continuously arranged on the axis of the axle (1), and the signal lead wire and the power feed lead wire to the force detector (4) are rotated. 6. The slip ring (9) is introduced into the slip ring (9) via the hollow hole (24) of the rotation transmission rod (10) of the goniometer (8), according to any one of claims 1 to 5. Axle dynamometer. 7. A numerical display section (IND) and a rotary switch (RS) for channel selection are provided for individually monitoring the output signals of each component processing channel, and variable signal levels and amplification factors are provided for each channel. final stage amplifier (AMP ₁ ~AMP ₆₎ axle dynamometer according to any one of claims 1 to 6, characterized in that is provided that allows.