阅读说明：本技术 向飞行器机轮的机电制动致动器供电的方法 (Method for supplying power to electromechanical brake actuators of aircraft wheels ) 是由 O·弗雷 F·皮特胡德 S·巴特勒米 于 2020-04-08 设计创作，主要内容包括：为此,本发明提供了一种对安装到飞行器机轮制动器的机电制动致动器(1)供电的方法,其中使递送到机电制动致动器的供电电流(I)饱和成饱和值(Isat),以限制由所述机电制动致动器消耗的电流,并从而限制由致动器展现的力。该方法包括在机电制动致动器工作时根据机电制动致动器的内部温度(T)来确定饱和值(Isat)的步骤。(To this end, the invention provides a method of powering an electromechanical brake actuator (1) mounted to an aircraft wheel brake, in which the powering current (I) delivered to the electromechanical brake actuator is saturated to a saturation value (Isat) to limit the current consumed by said electromechanical brake actuator and thus the force exhibited by the actuator. The method comprises a step of determining a saturation value (Isat) as a function of an internal temperature (T) of the electromechanical brake actuator when the latter is in operation.)

1. A method of powering an electromechanical brake actuator (1) mounted to an aircraft wheel brake, wherein the supply current (I) delivered to the electromechanical brake actuator (1) is saturated to a saturation value (Isat) to limit the current consumed by the electromechanical brake actuator (1) and thereby limit the force exhibited by the electromechanical brake actuator (1), the method being characterized in that it comprises the steps of: -determining said saturation value (Isat) as a function of the internal temperature (T) of said electromechanical brake actuator (1) when said electromechanical brake actuator (1) is operating.

2. Method according to claim 1, characterized in that the value of the approach current (Iapp) flowing through the electric motor (4) of the electromechanical brake actuator (1) during the approach phase at a given speed is measured, which value depends on the internal temperature of the electromechanical brake actuator (1), and in that an additional current (Δ I) is added to the measured value of the approach current to determine the saturation value (Isat Iapp + Δ I).

3. Method according to claim 2, characterized in that said additional current (Δ I) is constant and independent of the internal temperature of said electromechanical brake actuator (1).

4. Method according to claim 2, characterized in that the additional current (Δ I) is determined as a function of the internal temperature of the electromechanical brake actuator (1) or as a function of the value of the proximity current (Iapp).

5. A method according to claim 2, characterized in that the saturation value is adjusted such that it falls in a range from a predetermined minimum value (Imin) to a predetermined maximum value (Imax).

6. Method according to claim 2, characterized in that it is applied to a brake having a plurality of electromechanical brake actuators (1), wherein the approach current values (Iapp) of the electromechanical brake actuators (1) are compared to detect and eliminate any outlier and replace it with a corrected value, for example with the average of the approach current values that are not eliminated.

7. A method according to claim 1, characterized in that an internal temperature (T) of the electromechanical brake actuator (1) is measured and the saturation value (Isat) is calculated using the internal temperature.

8. A method according to claim 7, characterized in that said saturation value (Isat) is calculated from said temperature (T) by using a table or function of values (Isat ═ f (T)).

9. Method according to claim 7, characterized in that it is used for an electromechanical brake actuator with a single envelope, wherein for determining said internal temperature (T), a temperature sensor (7) is arranged to directly measure the temperature (T) of the lubricant of a mechanical transmission (3) arranged between the electric motor (4) and the thruster (2) of said electromechanical brake actuator (1).

10. The method according to claim 7, characterized in that it is applied to an actuator having two envelopes, of which a first envelope (10) contains the electric motor (4) of the electromechanical brake actuator (1) and a second envelope (9) contains the mechanical transmission (3) of the electromechanical brake actuator (1) and the thruster (2), wherein, for determining the internal temperature (T), a temperature sensor (7') is arranged in the first envelope (10) to indirectly measure the temperature (T) of the lubricant of the mechanical transmission (3) contained in the second envelope (9).

11. Method according to claim 7, characterized in that the method is applied to a brake having a plurality of electromechanical brake actuators (1), wherein the respective internal temperature measurements of the respective electromechanical brake actuators (1) are compared to detect and eliminate any extraneous measurement and replace it with a corrected value, e.g. with the average of the temperature measurements that have not been eliminated.

Technical Field

The present disclosure relates to a method of powering an electromechanical brake actuator of an aircraft wheel.

Background

Aircraft are generally provided with brakes for selectively applying braking torque on some of its wheels for slowing their rotation and thus for the purpose of decelerating the aircraft when the aircraft is moving on the ground.

Some brakes are provided with electro-mechanical actuators (EMA), each comprising a thruster (pusher) that is moved by an electric motor via a mechanical transmission to selectively apply a force to the friction members of the brake and thereby generate a braking torque.

The means for managing the electric power supplied to the brake EMA comprise means for saturating the consumption of electric current to protect the electric motor and limit the internal forces.

Brake EMAs are subjected to low temperatures in flight and also to high temperatures generated by their proximity to the friction components of the brakes, which emit significant amounts of heat during braking. Relatively low or high temperatures may also occur on the ground as a result of weather conditions. The mechanical transmission of the brake EMA contains a lubricant with physical characteristics that vary considerably as a function of temperature, so that the brake EMA possesses operating characteristics that are highly dependent on operating temperature. Typically, the lubricant possesses a high viscosity when cold, thereby reducing the mechanical performance of the actuator. In order to reach the same pressing force when cold, the motor therefore needs to deliver a higher torque than when hot and therefore needs to operate at a higher current than when hot. Therefore, the saturation of the electric power supply current needs to be set to a maximum value that is high enough for operation at cold. When hot, the lubricant is more fluid and causes less mechanical loss. If the motor is then operated with a current that reaches the maximum saturation value at low temperatures, the mechanical stresses in the mechanical transmission from the motor to the thruster are therefore greater, requiring overdimensioning of the components of the motor and of the mechanical transmission in order for them to be able to operate when hot.

Thus, optimal utilization of the brake EMA over a wide temperature range requires that several sub-components of the brake EMA be oversized, resulting in an increase in the weight and volume of the equipment.

Object of the Invention

The present invention seeks to provide a method of supplying power to the brake EMA of an aircraft to enable such dimensional over-gauging to be avoided.

Disclosure of Invention

To this end, the invention provides a method of powering an electromechanical brake actuator mounted to an aircraft wheel brake, in which the supply current delivered to the electromechanical brake actuator is saturated to a saturation value to limit the supply current consumed by said electromechanical brake actuator and thus the force exhibited thereby.

According to the invention, the method comprises a step of determining a saturation value as a function of an internal temperature of the electromechanical brake actuator when the latter is in operation. Thus, it is possible to temporarily increase the saturation value Isat when it is detected that the internal temperature of the electromechanical brake actuator is low, and it is possible to decrease the saturation value Isat when the electromechanical brake actuator is hot. Thus, the maximum force that can be exhibited by the electromechanical brake actuator is not at risk of increasing with a rise in temperature of the electromechanical brake actuator, thereby protecting the electromechanical brake actuator and its internal components.

In a first particular implementation of the invention, the value of the approach current flowing through the motor of the electromechanical brake actuator during the approach phase at a given speed is measured, and an additional current is added to the measured value of the approach current to determine the saturation value.

For a given travel speed, the approach current measured in this way at cold is greater than the same current Iapp measured at hot, which is a direct effect of the internal temperature of the electromechanical brake actuator. It is advantageous to use the unloaded movement of the electromechanical brake actuator for said measurement when the thruster of the electromechanical brake actuator travels towards the friction member of the brake. Sufficient time is available for the approach current to stabilize and for the measurements made in this way to be reliable.

The saturation value may be determined during each approach phase of the electromechanical brake actuator (i.e., each time the brake is applied).

In another particular implementation of the method of the invention, the saturation value is determined by using a measurement of the internal temperature of the brake actuator.

Drawings

The invention may be better understood from the following description of this particular implementation with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of a prior art aircraft brake including an electromechanical brake actuator acting on a friction member;

FIG. 2a is a graph plotting the current flowing through an electromechanical brake actuator when it is cold;

FIG. 2b is a graph plotting current flowing through an electromechanical brake actuator when hot;

FIG. 3 is a diagrammatic view of an electromechanical brake actuator having a single envelope and including a temperature sensor for performing the method of the present invention; and

FIG. 4 is a diagrammatic view of an electromechanical brake actuator having two envelopes and including a temperature sensor for performing the method of the present invention.

Detailed Description

With reference to fig. 1, the method of the invention is applicable to aircraft brakes having at least one electromechanical brake actuator 1, the electromechanical brake actuator 1 comprising a thruster 2, the thruster 2 being moved by an electric motor 4 operating via a mechanical transmission 3 to selectively exert a force on a friction member 5 of the brake, so as to generate a braking torque suitable to slow down the rotation of the associated wheel. The means 6 for managing the power supply deliver a supply current I to the electric motor 4 in response to a braking request from a pilot operating a brake pedal or from a braking control unit automatically generating set points for braking or deceleration.

In this example, to avoid any damage to the electromechanical brake actuator 1, the means 6 for managing the power supply comprise protection means for limiting the supply current I drawn by the actuator 1 to a saturation value, referred to herein as Isat.

In a first particular implementation of the method of the invention, as shown in fig. 2a and 2b, the approach current Iapp drawn by the electromechanical brake actuator 1 when the thruster 2 approaches the friction member 5 is measured. Preferably, the thruster 2 is made to move at a predetermined constant speed, so as to perform the respective measurement of the approach current Iapp under similar operating conditions. In the figures, it can be seen that, during the approach phase, the current I drawn by the electromechanical brake actuator 1 exhibits an initial transient and then stabilizes at the value Iapp. The current I then increases suddenly when the thruster 2 becomes in contact with the friction member 5. To determine the saturation current Isat, an additional current Δ I is added to the measured proximity current, thereby making it possible to set a saturation value Isat that depends on the internal temperature, since the proximity current Iapp depends heavily on said internal temperature. In particular, fig. 2a relates to an electromechanical brake actuator 1 operating cold, while fig. 2b relates to an electromechanical brake actuator operating hot. It can be seen that the proximity current Iapp is higher when cold than the same proximity current Iapp when hot, which has the following effect: the saturation value Isat when hot is lower than the saturation value when cold (marked with a dashed line in fig. 2 b). The reduction of the saturation value Isat when the electromechanical brake actuator 1 heats up makes it possible to avoid additional forces that may damage the electromechanical brake actuator.

In a first variant, the value of the additional current Δ I is constant and independent of the internal temperature of the electromechanical brake actuator, making it very simple to determine the saturation value. In a variant that is an alternative to the first variant, the additional current Δ I is made dependent on the internal temperature of the actuator, for example by setting it to a value proportional to the approach current. In a further variant, the saturation value Isat determined in this way is adjusted to fall between the minimum saturation value Imin and the maximum saturation value Imax if the saturation value Isat determined by the method of the invention falls outside these current values. The adjusting may comprise limiting the saturation value Isat to Imin in case Isat < Imin or to Imax in case Isat > Imax.

In a second particular implementation of the method of the invention, the electromechanical brake actuator is provided with a temperature sensor for measuring the internal temperature T of the electromechanical brake actuator 1, and in particular the temperature of the lubricant contained in the mechanical transmission, when the electromechanical brake actuator 1 is in operation. This temperature measurement then makes it possible to calculate the saturation value Isat from the internal temperature of the actuator (for example, by using a table of values included in a memory and giving Isat from the value of T, or by using a pre-programmed function Isat ═ f (T)). This calculation may be performed continuously, or at regular intervals.

Fig. 3 shows the temperature sensor 7 mounted in the electromechanical actuator 1 with a single envelope, i.e. the electric motor 4 and the mechanical transmission 3 are contained in the same envelope 8, indicated by the dashed line. A temperature sensor 7 is mounted on the mechanical transmission 3 to measure the temperature of the lubricant in the mechanical transmission 3 as directly as possible.

Fig. 4 shows the temperature sensor 7' mounted in the electromechanical brake actuator 1 with two envelopes, in which the electric motor 4 is contained in a first envelope 10 and the mechanical transmission 3 and the thruster 2 are contained in a second envelope 9, the envelopes 9 and 10 being assembled together to constitute the electromechanical brake actuator 1. In this case, the temperature sensor 7' is preferably fastened to the envelope 9 containing the electric motor 3, so as to be able to group its respective electrical connections with those of the electric motor 3. The temperature of the lubricant in the mechanical transmission is then measured indirectly, for example by conduction through the second jacket 9.

Preferably, if the brake is provided with a plurality of electromechanical brake actuators, the internal temperature measurements from each electromechanical brake actuator are compared to detect and eliminate any extraneous measurement and replace it with an acceptable value (e.g. with an average of the temperature measurements that have not been eliminated). In a variant, it is possible, in addition or alternatively, to use a temperature eliminated from the proximity current Iapp.

The invention is not limited to what has been described above, but on the contrary covers any variant coming within the scope defined by the claims.

In particular, the brake may have a different structure than that described and illustrated, as may the electromechanical actuator.

When the method of the invention is applied to a brake having a plurality of electromechanical brake actuators 1, the method may advantageously comprise the steps of: the values of the respective approach currents Iapp from the respective electromechanical brake actuators 1 are compared in order to detect and eliminate any outlier and replace it with a corrected value (for example, the average of the values of the approach currents that are not eliminated).