JPH05164658A - Power absorption device of chassis dynamometer using magnetic particle - Google Patents

Abstract

PURPOSE:To realize a power-absorption device which is compact and has an improved controllability by controlling a cooling capacity of a cooling device which is utilized for temperature control and energy absorption of a magnetic circuit according to absarftim power such as a rotary velocity and an excitation current. CONSTITUTION:A magnetic flux density is controlled by an excitation current, a magnetic particle 13 is gathered between a magnetic pole 14 and a rotor 12a according to the magnetic flux density, a resistance for rotation is generated in semi-solid shape, a force is generated between an input axis 11 and a fixed stator 17, a power of an input axis 11 is absorbed, but the energy becomes a friction heat of the particle 13, etc., so that it is excluded by a cooling water 19. A flow rate control of the cooling water 19 is performed by detecting the number of revolutions of the input axis 11 and an excitation current and then taking them into a calculation circuit and then changing an amount of opening of a control valve 21 continuously or in steps at a temperature T1 near the particle 13 and a cooling water exit temperature T2. When the temperature T1 reaches a certain limit, the excitation current is reduced to a proper value, thus enabling absorption power, namely a heat generation amount to be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power absorption device for carrying out test evaluation, maintenance, etc. of an automobile in relation to pollution prevention measures for the automobile.

[0002]

2. Description of the Related Art There are various chassis dynamometers for carrying out load tests by operating an automobile as a vehicle. The power absorbing devices are direct current electric dynamometer, eddy current electric dynamometer, water dynamometer, and electromagnetic dynamometer. Expression retarders have been used.

[0003]

While all of these dynamometers have the advantage that they can have a large power absorption capacity, they are large and heavy, and are housed inside the left and right rollers on which the driving wheels of an automobile can be placed. It was difficult to do. Generally, for a vehicle such as a passenger car that is lightweight and has relatively small power absorption in a low speed region, the capacity of the power absorption device may be small, and downsizing has been particularly desired. Conventionally,
Even if a da was used, it had to be placed on the outside of the roller, and inevitably an increase in size. Further, in the conventional power absorption by the retarder and the eddy current electric dynamometer, it is difficult to set the load at high speed with high accuracy because the braking torque characteristic in the low speed region lacks stability.

As described above, the chassis dynamometer is designed to be compact and lightweight, and is mainly used for driving in urban areas.
Load setting with high accuracy in the vehicle speed range of Km / h or less,
What can be easily done is a challenge to widely utilize chassis dynamometers.

The present invention has been made in view of the above-mentioned circumstances, and as a power absorbing device which is accurately downsized in a low speed region, magnetic powder is used in a magnetic circuit to prevent slippage depending on magnetic flux. It is an object of the present invention to realize a small-sized power absorption device with good controllability, which has a small rotational inertia and a quick response by using a kind of electromagnetic brake whose resistance torque changes.

[0006]

To solve this problem, the power absorber for a chassis dynamometer according to the present invention constitutes a part of a magnetic circuit using magnetic powder and electromagnetically absorbs its magnetic flux. In a chassis dynamometer equipped with a power absorption device that adjusts the braking force of the rotating shaft by controlling, when the cooling device is used for temperature control and energy absorption of the magnetic circuit, the cooling capacity of the cooling device is changed to the rotation speed. The feature is that continuous or stepwise control is performed according to absorption power such as exciting current.

[0007]

[Operation] There are two types of electromagnetic brakes using magnetic powder: air-cooled type and water-cooled type. When using this chassis dynamometer, use the water-cooled type with good cooling properties to absorb most of the absorbed energy. The water is eliminated by the temperature rise, and the braking torque is generated accurately and stably by the exciting current.
Then, the flow rate of the cooling water is controlled so that it can be maintained under optimum conditions.

Since the generated braking torque T changes according to the exciting current i as shown in FIG. 1, this relation is approximated by the equation (1).
Is set in the function generator 25 according to, and the current value for the required braking torque is determined. This relationship can be approximately expressed as T = a ₀ + b ₀ i + c ₀ i ² + d ₀ i ³ (1). a ₀ , b ₀ , c ₀ , d ₀ can be determined in advance by actual measurement, and this relational expression can be obtained by the function generator 25.
Since the generated torque value T is determined by the signal of the current value i, i can be obtained from T.

The running resistance of the vehicle changes depending on the rolling resistance of tires or the like, air resistance, acceleration resistance, uphill resistance, etc. Generally, the driving force F can be approximately represented by the equation (2). F = A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² + E ₀ M (dv / dt) + F ₀ Msinθ (2)

Here, M is the mass of the vehicle, V is the speed of the vehicle, A is the front projected area of the vehicle, and θ is the slope angle of the road. In the case of flat ground and steady running, sin θ = 0, (dv
/ Dt) = 0 and F = A ₀ + B ₀ M + C ₀ MV + D ₀ A
It becomes V ² . A ₀ , B ₀ , C ₀ , D ₀ are constants depending on the conditions of the vehicle, road, and tire, but empirical values can be assumed.

On the other hand, the torque on the roller side that receives the rotational force of the driving force F from the tire of the vehicle, including the loss on the tire on the idler side in the case of a double roller, is a loss x due to deformation of the tire. Therefore, the radius r ₀ of the roller and the driving force F
Of the product F · r ₀ . Considering the power transmission efficiency η _m from the roller shaft to the power absorber, the rotational equivalent inertial mass I ₀ on the chassis dynamometer side including the roller is also taken into consideration.
Then, the shaft torque T to be braked by the power absorption device is as follows when converted to the roller shaft and _expressed as T _r . T _r = r ₀ [η _m {A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² + E ₀ M (dv / dt) + F ₀ Msinθ−x} −I ₀ (dv / dt)] (3)

If the reduction ratio between the roller shaft and the shaft of the power absorber is 1 / m, then T = mT _r . That is, T = mr ₀ [η _m {A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² + E ₀ M (dv / dt) + F ₀ Msinθ−x} −I ₀ (dv / dt)] (4)

In the case of flat ground and steady running, T = mr ₀ η _m {A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² -x} (5)

Further, since the ratio of the air resistance is relatively small in the low speed region, it is possible to use an assumed value for the coefficient D _{0 and the} like. Further, with respect to the value of x and the like, empirical values can be used depending on the roller diameter and tire rigidity, particularly air pressure. Using this relationship, the braking torque T can be obtained by the function generator 24 according to the speed V in the case of the vehicle mass M.

In an electromagnetic brake using magnetic powder, the powder heats up in accordance with braking energy. For this reason, cooling is very important. In the present invention, cooling water is used, and this can be controlled according to the absorption power, that is, the heat generation amount. That is, since the calorific value according to the product of the signal n _s of the rotational speed exciting current signal i _s varies, thereby controlling the cooling water flow rate.

Alternatively, the cooling water flow rate is controlled by detecting the temperature of a portion near the heat generating portion of the power absorption device. Furthermore, when the amount of cooling water is maximum, and when the temperature of the part near the heat generating part reaches a certain limit, the exciting current is controlled to perform a protective control so that the magnetic powder etc. is not overheated. To do.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. 3, 4 and 5.

In the power absorber 10, a rotor 12a connected to an input shaft 11 supported by bearings 18 and 18a is made of a material having a high magnetic permeability, and a magnetic flux 16 formed by an exciting coil 15 is a magnetic pole on a fixed side. A magnetic circuit that passes through the magnetic powder 13 disposed in the gap between the rotor 14 and the rotor 12a and passes through the ring-shaped gap is formed. At this time, the magnetic flux density is controlled by the exciting current, and the magnetic powder agglomerates between the magnetic pole and the rotor in accordance with the magnetic flux density, and becomes a semi-solid state to generate resistance to rotation. As a result, a braking force is generated between the input shaft 11 and the fixed stator 17,
The power of the input shaft is absorbed, but its energy becomes frictional heat of the magnetic powder or the like, and this is removed by the cooling water 19. Pole 14 near the cooling water passage 20a, the provided 20b, the exciting coil,励極, magnetic powder, and to cool the rotor to a suitable temperature, as well as installing a temperature sensor T _1, T _2, cooling A water control valve 21 is placed.

The cooling water flow rate is controlled by the temperature T near the magnetic powder.
₁ detects the rotational speed and exciting current of the input shaft in addition to the cooling water outlet temperature T _2, performs capture the signals to computation circuit.

As shown in FIGS. 4 and 5, the chassis dynamometer 30 is a power roller 31a, 3 which rotates with wheels 39 mounted thereon.
1b and 32a, 32b, power absorption roller 31a,
31b is connected to the shaft 3 via the clutch 34 and the coupling 35.
Bearings 38a, 38b, 38c, 3
Gear 3 supported by 8d and mounted on shaft 33
The power is transmitted from the input shaft 11 to the power absorption device 10 via the gear 6a and the gear 36b meshing with each other. On the other hand, the idler rollers 32a and 32b are provided with respective bearings 38e ...
It is supported by 38h and can rotate freely by connecting the shafts.

The wheels 39, which are the driving wheels of the vehicle, are the rollers 31.
a, 32a and 31b, 32b are in contact with the respective rollers to transmit the driving force to the power absorbing rollers 31a, 31b, the braking force of which is generated by the exciting current i of the power absorbing device 10 shown in FIG. It is decided like.

The excitation current i is usually determined by the function generator 25 in the controller of FIG. In the function generator 25, the braking torque T is determined by the equation (1),
T is determined by the function generator 24 according to the equation (4), and is input to the function generator 25. In the function generator 24, m, r ₀ and I ₀ are constants determined by the chassis dynamometer, and η _m is an empirical constant value.
Further, A ₀ , B ₀ , C ₀ , D ₀ , E ₀ , and F ₀ can be input as constants based on empirical values or E ₀ and F ₀ as 1 depending on the unit system. x is an empirical value due to tire pressure, and D ₀ is also a coefficient that changes depending on the vehicle shape. M is the mass of the vehicle, and A is the front projected area of the vehicle, which is input for each vehicle. The slope θ of the road is input as necessary. As a result, the function generator 2
4, when the vehicle speed signal is input from the revolution counter 37 of the roller shaft 33, the required control torque T according to the equation (4) is calculated. The exciting current i is determined by the function generator 25 according to this T, and the electromagnetic brake 10 using magnetic powder is used.
The absorption braking torque of is generated.

The braking torque causes the wheels 39 of the vehicle.
Receives a braking force equivalent to that when actually traveling on the road. Then, for example, the engine and the exhaust gas can be tested and evaluated under the same conditions as on the road.

At this time, in the electromagnetic brake, the product of the exciting current i _s and the rotation speed signal n _s is controlled by the flow rate control signal circuit 26 so that cooling is performed with an appropriate amount of cooling water according to the absorption power, that is, the amount of heat generation. Is used as an index to change the valve opening amount of the control valve 21 for flow control continuously or in steps. Further, at this time, when the temperature T ₁ near the magnetic pole of the electromagnetic brake reaches a certain limit or more, the exciting current is reduced to an appropriate value to suppress the absorption power, that is, the heat generation amount.

As a cooling device, in addition to the cooling water described above, a device using a heat pipe as shown in FIG. 6 can be applied to a power absorbing device for electromagnetic powder. The cylinder 12b, which rotates in the same manner as the input shaft 11, passes the magnetic powder 13 when the magnetic flux passes through the magnetic flux blockers 49a and 49b which do not short-circuit the magnetic circuit 16 and the fixed side rotor 4
8 and 8 are concentrated to generate a braking force. The heat generated at this time is released to the outside by the heat pipe 40. In the heat receiving portion 43 of the heat pipe 40, the heat medium is vaporized.
It evaporates and absorbs a large amount of heat, and the vapor 41 (heat medium) rapidly moves to the heat radiating portion 44a.

A cooling fan 44b is provided in the heat radiating portion 44a, and the cooling fins 44b are cooled by the cooling air generated by the blower blades 46 rotated by the motor 45, and the heat from the heat radiating portion 44a is released. When the heat receiving portion 43 of the heat pipe 40 is arranged in contact with the fixed rotor, the heat generated by the power absorption can be effectively released to the outside with a small temperature difference. In such a cooling device, the cooling motor 45 is intermittently controlled or otherwise controlled by the controller 47. At this time, the temperature T ₁ is used as _one of the control input signals.

[0027]

As described above, in the present apparatus, the compact and highly controllable absorber can be arranged between the rotors of the chassis dynamometer, and the running test of the automobile can be easily carried out in a small space.

[Brief description of drawings]

FIG. 1 is a graph showing a control torque characteristic of a brake using electromagnetic powder.

FIG. 2 is an explanatory diagram of a configuration of a control device.

FIG. 3 is a vertical cross-sectional explanatory view of a power absorption device.

FIG. 4 is a front explanatory view of the chassis dynamometer.

FIG. 5 is a side view of the chassis dynamometer.

FIG. 6 is a vertical cross-sectional explanatory view of another power absorbing device.

[Explanation of symbols]

10 Power Absorbing Device 11 Input Shaft 12a Rotor 12b Cylinder 13 Magnetic Powder 14 Magnetic Pole 15 Magnetic Coil 16 Magnetic Flux 17 Stater 18a Bearing 18b Bearing 19 Cooling Water 20a Passage 20b Passage 21 Control Valve 24 Function Generator 25 Function Generator 26 Flow rate control signal circuit 30 Chassis dynamometer 31a Roller 31b Roller 32a Roller 32b Roller 33 Roller shaft 34 Clutch 35 Coupling 36a Gear 36b Gear 37 Rotation meter 38a Bearing 38b Bearing 38c Bearing 39 Wheel 40 Heat pipe 41 Steam 43 Heat receiving part 44a Radiating part 44b Cooling fin 45 Motor 46 Blower blade 47 Controller 48 Fixed side rotor 49 Magnetic flux blocker T ₁ , T ₂ Temperature sensor

Claims (6)

[Claims] 1. A chassis dynamometer provided with a power absorbing device that comprises a part of a magnetic circuit using magnetic powder and electromagnetically controls the magnetic flux to adjust the braking force of a rotating shaft. When using a cooling device for temperature control and energy absorption of a magnetic circuit, the chassis dynamometer is characterized in that the cooling capacity of the cooling device is controlled continuously or stepwise according to the absorption power such as rotation speed and exciting current. Power absorption device 2. When a cooling device that uses cooling water is used as the cooling device, the flow rate of the cooling water is controlled continuously or stepwise according to the absorption power such as the rotation speed and the exciting current. Item 1. A power absorber for a chassis dynamometer according to Item 1. 3. A power absorber for a chassis dynamometer according to claim 2, wherein the flow rate of the cooling water is controlled by detecting the temperature of a part of the power absorber. 4. The power absorption device for a chassis dynamometer according to claim 2, wherein the generated energy is controlled by electromagnetic control under the maximum cooling water flow rate condition. 5. The relationship between the exciting current i and the generated braking torque T is approximated by T = a ₀ + b ₀ i + c ₀ i ² + d ₀ i ³ ,
The chassis dynamometer according to claim 2, 3 or 4, further comprising an electromagnetic control circuit for setting a function generator and automatically supplying an exciting current i to a required control torque T. Power absorber. 6. The relationship between the driving force F of the wheels, the vehicle mass M, and the speed V is expressed as follows: F = A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² + E ₀ M (dv / dt) + F ₀ When Msin θ is set and the rotational force of the roller received from the wheel is controlled by a power absorber connected at a reduction ratio 1 / m, the roller radius r ₀ , transmission efficiency η, and equivalent inertia mass I ₀ of the chassis dynamometer , And the loss x such as excessive tire deformation on the roller surface is taken into consideration, the braking torque T is calculated by T = m · r ₀ [η _m {A ₀ + B ₀ M + C ₀ MV + D ₀ AV ² + E ₀ M (dv / dt) + F ₀ Msin θ−x} −I ₀ (dv / dt)], and the relationship between the vehicle speed V and the braking torque T can be set by using the vehicle mass M and other necessary factors. Power absorption device for chassis dynamometer according to 3, 4, or 5.