JP5384974B2 - Electric brake - Google Patents

Description

  The present invention relates to an electric brake that drives a braking member of a wheel with an electric motor.

  In recent years, in order to reduce or eliminate the hydraulic pressure source mounted on an aircraft, there is a tendency to change a brake for braking a wheel from a hydraulic brake to an electric brake.

  By the way, in the disc type brake, a predetermined clearance is provided between the piston and the disc so that the piston does not contact the disc when the brake is released. Due to this clearance, it takes time to start braking after operating the electric brake, and the aircraft runs idle during that time. For this reason, it is necessary to perform the operation until the piston is brought close to and brought into contact with the disk in as short a time as possible.

  Patent Document 1 discloses a servo control method in a brake system including an electric brake.

JP 2006-232270 A

  However, if the piston is moved at a high speed in order to bring the piston into contact with the disk in a short time, an impact force is generated when the piston and the disk come into contact with each other. Due to this impact force, there is a risk that the braking force momentarily increases excessively.

  Accordingly, an object of the present invention is to provide an electric brake capable of bringing the piston into contact with the disk in a short time and capable of reducing the impact when the piston contacts the disk.

The present invention includes a rotating disk that rotates together with a wheel, a wheel control unit that is supported so as not to rotate with respect to the airframe, and that is displaceable toward the rotating disk, and a piston that is capable of moving back and forth toward the wheel control unit. An electric actuator that linearly moves the piston, a controller that controls the operation of the electric actuator, and a braking command device that is operated by a driver and outputs a braking command to the controller based on the operation. An electric brake that generates a braking torque by the electric actuator pressing the wheel control means toward the rotating disk via the piston, wherein the controller is provided between the piston and the wheel control means. Clearance storage means for storing the clearance of the vehicle and whether or not the braking command device has been operated. And an operation detection means for detecting the operation of the braking command device, and a piston for issuing a signal for moving the piston toward the wheel control means by the clearance stored in the clearance storage means. A contact means; and a speed reduction means for processing a signal from the piston contact means and outputting a first control signal of a first-order lag system that decelerates the piston before the piston contacts the wheel control means; A brake that calculates an operating stroke of the piston after the piston abuts against the wheel restraining means based on a braking command output by the braking command device, and outputs a second control signal corresponding to the operating stroke It includes a command piston stroke conversion portion, an adder for outputting the first control signal and said second control signal and adding to the said adder And controlling the electric actuator based on the output signal.

According to the present invention, a braking command is input from the braking command device, and the piston abutting means decelerates the piston by the deceleration means before the piston abutting means moves the piston by the clearance and abuts against the non-rotating disk. Therefore, it is possible to prevent an impact force from being generated when the piston contacts the disk.

  Therefore, the piston can be brought close to the disk in a short time, and the impact when the piston comes into contact with the disk can be reduced.

It is the figure which showed the upper half from the central axis of the electric brake which concerns on embodiment of this invention in the cross section. It is a block diagram of control of an electric brake. It is a graph figure of piston displacement with respect to time at the time of electric brake operation.

  Hereinafter, an electric brake 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the electric brake 100 will be described with reference to FIG. A center axis O in FIG. 1 is a center axis of an unillustrated airframe shaft (hereinafter referred to as “axle”) fixed to an unillustrated airframe.

  The electric brake 100 is a multi-disc disc type brake provided inside a wheel (not shown). The electric brake 100 is used as a brake for braking an aircraft wheel.

  The wheel is configured by attaching a tire (not shown) to the outer periphery of the wheel (not shown). The wheel is attached to the axle via a bearing (not shown). That is, the axle does not rotate even if the wheel rotates.

  The electric brake 100 includes a rotating disk 6 that rotates integrally with a wheel, and a non-rotating disk 4 that is attached to an axle and does not rotate. The electric brake 100 presses the rotating disk 6 and the non-rotating disk 4 in contact with each other, and generates a braking torque by a frictional force.

  A plurality of the rotating disks 6 are provided at a predetermined interval. The non-rotating disk 4 is provided on both surfaces of the rotating disk 6. Therefore, a plurality of non-rotating disks 4 are also provided at a predetermined interval. In the electric brake 100, the three rotating disks 6 are sandwiched between the four non-rotating disks 4. The number of each of the non-rotating disk 4 and the rotating disk 6 is set according to the required braking force or the like, and is not limited to this number.

  The rotating disk 6 has a disk shape in which a circular hole is formed at the center. The outer periphery of the rotating disk 6 is supported by the inner periphery of the wheel, and rotates together with the wheel. The rotating disk 6 is supported so as to be displaceable in the axle direction with respect to the wheel, that is, slidable.

  The non-rotating disk 4 has a disk shape in which a circular hole is formed at the center. The inner periphery of the non-rotating disk 4 is supported on the axle via the torque tube 3. The non-rotating disc 4 does not rotate even if the wheel rotates. The non-rotating disc 4 is supported so as to be displaceable in the axle direction, that is, slidable. This non-rotating disk 4 corresponds to the wheel control means. In the case of a caliper type disc brake instead of the multi disc type as in the electric brake 100, for example, a brake pad can be provided as a wheel control means.

  The torque tube 3 has a bobbin shape in which disk-shaped flange portions 3b and 3c are provided at both ends in the axial direction of a cylindrical cylindrical portion 3a. The flanges 3b and 3c need not be disk-shaped, and for example, a plurality of protrusions corresponding to the positions where the piston 28 and the disk presser 3d are provided may be formed. The torque tube 3 supports a plurality of non-rotating disks 4 on the outer periphery of the cylindrical portion 3a. A gap is provided between the torque tube 3 and the rotating disk 6 so that the torque tube 3 and the rotating disk 6 do not contact each other. That is, the diameter of the hole formed at the center of the rotating disk 6 in the radial direction is formed so as not to contact the torque tube 3. Is also formed large.

  One flange portion 3 c of the torque tube 3 is attached to the axle via the housing 2. A disk presser 3 d is provided on the other flange 3 b of the torque tube 3. Between the piston 28 protruding from the housing 2 and the disk retainer 3d, the rotating disk 6 and the non-rotating disk 4 are pressed so as to contact each other. Therefore, the torque tube 3 receives a reaction force of a force that presses the rotating disk 6 and the non-rotating disk 4.

  The housing 2 is fixed to the axle, and an electric motor 21 as an electric actuator for driving the electric brake 100, a speed reduction mechanism 24 for reducing the rotation of the electric motor 21 and transmitting it to the ball screw 25, and a piston pushed out by the ball screw 25 28 in the inside.

  The piston 28 is provided to face the non-rotating disk 4 so as to be able to advance and retreat toward the non-rotating disk 4. The piston 28 is formed integrally with the ball nut 26 of the ball screw / nut mechanism 27. X0 in FIG. 1 is a clearance between the piston 28 and the non-rotating disk 4. That is, the piston 28 faces the non-rotating disk 4 with a clearance X0. The piston 28 is driven by the electric motor 21 so as to advance and retreat with respect to the non-rotating disk 4. Plural pistons 28 are arranged at predetermined intervals in the rotational circumferential direction of the wheel. The number of pistons 28 and the number of electric motors 21 are arbitrarily set according to the braking force required for the electric brake 100 and the like.

  The clearance X0 between the piston 28 and the non-rotating disk 4 when the braking of the electric brake 100 is released varies depending on the amount of wear of the non-rotating disk 4 and the rotating disk 6. That is, when the thickness of the non-rotating disk and the rotating disk 6 decreases due to wear, the clearance X0 between the piston 28 and the non-rotating disk 4 when the piston 28 returns is increased. Therefore, it is necessary to confirm the clearance X0 before braking the electric brake 100.

  In the electric brake 100, the clearance X0 as a clearance storage means is the clearance X0 between the piston 28 and the non-rotating disc 4 at the time of the previous braking, that is, the distance that the piston 28 is separated from the non-rotating disc 4 when the braking is released. 34 (see FIG. 2). Thereby, it is possible to control the electric brake 100 based on X0 stored at the time of the latest braking. When the control is performed so that the clearance X0 between the piston 28 and the non-rotating disk 4 is kept at a predetermined value, the predetermined value X0 is stored.

  A plurality of (for example, 4 to 6) electric motors 21 are provided in the housing 2 corresponding to the number of pistons 28. The electric motor 21 linearly moves the piston 28 via the speed reduction mechanism 24, and presses the piston 28 against the non-rotating disk 4, so that the non-rotating disk 4 and the rotating disk 6 are pressed against each other. As a result, a frictional force is generated at the sliding surface portion between the non-rotating disk 4 and the rotating disk 6 so that a braking torque is obtained.

  The electric motor 21 includes a rotation angle sensor 21a (see FIG. 2) as rotation angle detection means that can detect the rotation angle and the rotation speed. As the electric motor 21, a motor having a rotation angle detecting means such as an AC servo motor or a stepping motor is used. You may make it the structure which provides rotation angle detection means, such as a rotary encoder, as a member different from the electric motor 21. FIG.

  The speed reduction mechanism 24 is configured to transmit the rotation of the electric motor 21 to the ball screw 25. The speed reduction mechanism 24 includes a drive gear 22 connected to the motor shaft 29 of the electric motor 21 and a driven gear 23 connected to the base end portion of the ball screw 25. The speed reduction mechanism 24 transmits the rotation of the drive gear 22 to the driven gear 23. In the electric brake 100, a gear having a smaller number of teeth and a smaller diameter is used as the drive gear 22, and a gear having a larger number of teeth and a larger diameter than the drive gear 22 is used as the driven gear 23. That is, the rotation of the electric motor 21 is decelerated and transmitted to the ball screw 25.

  The ball screw / nut mechanism 27 is interposed inside the piston 28. The ball screw / nut mechanism 27 protrudes to the inside of the piston 28, is fixed to the driven gear 23 and rotates as a unit, and the ball nut 26 is fixed to the piston 28 and advances / retreats with respect to the non-rotating disk 4. Is provided. The ball nut 26 is screwed onto the ball screw 25 via a large number of balls (not shown). The ball screw / nut mechanism 27 converts the rotational motion of the ball screw 25 into linear motion, and moves the piston 28 forward and backward with respect to the non-rotating disc 4.

  By the way, the aircraft control system outputs a braking command according to an operation amount of a brake pedal (not shown) as a braking command device operated by a pilot. The aircraft is provided with a controller 30 that controls the operation of the electric motor 21 based on the output braking command.

  The controller 30 controls the electric brake 100 and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an I / O interface (input / output interface). Consists of a microcomputer. The RAM stores data in the processing of the CPU, the ROM stores a control program of the CPU in advance, and the I / O interface is used for input / output of information with the connected device. Control of the electric brake 100 is realized by operating a CPU, RAM, and the like according to a program stored in the ROM.

  A signal from the brake pedal is input to the CPU via the I / O interface. The CPU calculates a piston pressing force command value signal corresponding to the input signal. The CPU outputs a command drive current io corresponding to the piston pressing force command value signal to the electric motor 21 via the I / O interface, and the electric motor 21 is rotated. The driving force of the electric motor 21 is transmitted to the piston 28 via the speed reduction mechanism 24 and the ball screw / nut mechanism 27, and a piston pressing force is generated. At this time, the rotation angle θ of the motor shaft 29 of the electric motor 21 is detected by the rotation angle sensor 21 a and input to the controller 30 together with the actual drive current i of the electric motor 21. A current sensor 21 b shown in FIG. 2 is provided inside the controller 30. The control of the piston pressing force will be described in detail later with reference to FIG.

  In the electric brake 100, the electric motor 21 rotates in the positive direction by the output from the controller 30, so that the piston 28 contacts the non-rotating disk 4 and presses each non-rotating disk 4 against each rotating disk 6. can get. On the other hand, when the electric motor 21 is rotated in the reverse direction by the command drive current io, the pistons 28 are separated from the non-rotating disks 4 and the non-rotating disks 4 are not pressed against the rotating disks 6 and the braking is released. Is done.

  Hereinafter, the control of the piston pressing force of the electric brake 100 will be described with reference to FIGS. 2 and 3.

  The pedal input sensor 31 detects an input from a brake pedal by a pilot, that is, a braking command. The pedal input sensor 31 can detect not only the input from the brake pedal but also the depression amount and depression acceleration of the brake pedal.

  The brake command / piston stroke conversion unit 32 calculates the operation stroke of the piston 28 based on the brake command input from the brake pedal. The operating stroke of the piston 28 is determined in advance by a map in which the operating stroke increases in proportion to the brake command. There may be a plurality of maps, and the best one is selected according to the situation.

  In the map for converting the brake command into the operation stroke of the piston 28, for example, as shown in FIG. 2, the operation stroke increases in proportion to the brake command. When the amount of depression of the brake pedal is small, the operation stroke of the piston 28 is small, and when the amount of depression of the brake pedal is large, the operation stroke of the piston 28 is large.

  The pedal input determination unit 33 determines whether or not there is a pedal input by a pilot. The pedal input determination unit 33 determines whether or not the brake pedal has been operated by a minimum amount that can output a braking command without waiting for detection of the pedal depression amount and depression acceleration. Specifically, it is determined whether or not the actual operation amount of the brake pedal exceeds the operation amount of the brake pedal set in advance as a minimum amount. This pedal input determination unit 33 corresponds to the operation detection means. If it is determined that there is an input from the brake pedal, the switch 40 is switched.

  The switch 40 is electrically connected to the zero input unit 41 in a normal state. The zero input unit 41 always outputs 0. When the switch 40 is switched, a signal from the clearance measuring unit 34 can be transmitted to the low-pass filter 50.

  The clearance measuring unit 34 stores the value of the clearance X0 at the time of the previous braking, and issues a signal for moving the piston 28 by the amount of the clearance X0. This signal is a step input as indicated by a broken line in FIG. The clearance measuring unit 34 and the switch 40 correspond to the piston contact means.

  The low pass filter 50 is provided between the switch 40 and the adding unit 35. This low-pass filter 50 corresponds to a deceleration means. The low-pass filter 50 cuts high frequency that is equal to or higher than the set frequency. As a result, a first-order lag output can be obtained with respect to the step input as shown by the solid line in FIG. The same control can be performed by software processing in the controller 30 without providing the low-pass filter 50.

  By providing the low-pass filter 50, the amount of increase in the operating stroke of the piston 28 that has been proportionally increased gradually decreases. Then, when the predetermined value is reached, a sufficiently gentle curve is drawn. Therefore, when the piston 28 comes into contact with the non-rotating disk 4, the increase amount of the operating stroke, that is, the moving speed becomes extremely small, and it is possible to prevent an impact force from being generated when the piston 28 contacts the non-rotating disk 4. .

The addition unit 35, a signal from a brake command piston stroke conversion unit 32 (the second control signal), signals that have flowed through the low pass filter 50 (first control signal) and adding to the set value X1 Is output. The set value X1 is instructed to the electric motor 21 while being feedback controlled by two transfer functions G, H of PID (Proportional, Integral, Differential) type.

  In the transfer functions G and H, feedback control is performed while comparing the set value X1 output from the adder 35 and the command drive current io for driving the electric motor 21 with the actual position of the piston 28 and the drive current i. Do. Specifically, it is as follows.

  A rotation angle sensor 21 a provided in the electric motor 21 detects the rotation angle of the motor shaft 29 and calculates the actual position of the piston 28. The control deviation εx is calculated by subtracting the actual position of the piston 28 from the set value X1 output from the adder 35. This control deviation εx is processed by the transfer function G and converted to the current set value i1.

  The control deviation εi is calculated by subtracting the current set value i1 from the actual current value of the electric motor 21 detected by the current value detecting means. The control deviation εi is processed by the transfer function H, and the command drive current io that is an output value is input to the electric motor 21.

  Hereinafter, the operation of the electric brake 100 will be described.

  When the brake pedal is not operated by the pilot, the switch 40 is connected to the zero input unit 41 side. At this time, a signal for moving the piston 28 by the clearance X0 is issued from the clearance measuring unit 34, but the signal becomes 0 by the zero input unit 41 and nothing is input to the low-pass filter 50. It becomes.

  The brake command / piston stroke conversion unit 32 determines that there is no brake command because the brake pedal is not operated, and does not issue a signal.

  From the above, since the signal for moving the piston 28 by the clearance X0 is 0 and no signal is issued from the brake command / piston stroke conversion unit 32, the command drive current io is added to the electric motor 21. Not. That is, the electric brake 100 does not operate.

  When the pilot operates the brake pedal, the pedal input determining unit 33 determines that the brake pedal has been operated by a minimum amount that can output a braking command, and switches the switch 40. The switch 40 is switched to the side to which the signal from the clearance measuring unit 34 is transmitted, and the signal from the clearance measuring unit 34 is input to the low pass filter 50.

  A step input signal for bringing the piston 28 emitted from the clearance measuring unit 34 into contact with the non-rotating disk 4 is converted into a first-order lag system by the low-pass filter 50. Therefore, an input signal indicated by a broken line in FIG. 3 is converted into a solid line signal and output.

  The operation stroke converted into the first-order lag system by the low-pass filter 50 is combined with the operation stroke converted by the brake command / piston stroke conversion unit 32, is subjected to feedback processing with the transfer functions G and H, and is output to the electric motor 21. The

  As described above, when a brake command is input from the brake pedal, first, the piston 28 is moved by the clearance X0 between the piston 28 and the non-rotating disc 4 by the signal converted into the first-order lag system by the low-pass filter 50. Therefore, the piston 28 is brought into contact with the non-rotating disk 4.

  At this time, due to the first-order lag signal obtained by the low-pass filter 50, the amount of increase in the operating stroke when the piston 28 comes into contact with the non-rotating disk 4, that is, the moving speed becomes extremely small. It is possible to prevent an impact force from being generated when it comes into contact with.

  Thereafter, the operating stroke of the piston 28 is controlled in accordance with a map output from the brake command / piston stroke conversion unit 32 corresponding to the mode of the braking command input from the brake pedal.

  According to the above embodiment, the following effects can be obtained.

A braking command from the brake pedal is inputted, the piston 28 by the braking command prior to an amount corresponding contact the non-rotating disk 4 is moved in the clearance X0, the piston 28 by the primary delay system signals obtained by the low-pass filter 50 Decelerated. Thereby, it is possible to prevent an impact force from being generated when the piston 28 contacts the non-rotating disk 4.

  Also, it does not wait for the brake pedal depression amount or depression acceleration to be detected, and only determines whether or not the brake pedal has been operated by the minimum amount that can output a braking command, and stores the stored clearance. The piston 28 is moved by X0. Therefore, the time from when the braking command is issued until the electric brake 100 is braked can be shortened.

  Therefore, the piston 28 can be brought close to the non-rotating disk 4 within a short time, and the impact when the piston 28 contacts the non-rotating disk 4 can be reduced.

  Further, since the low-pass filter 50 is a first-order lag filter, the speed when the piston 28 abuts against the non-rotating disk 4 is substantially the same even if the clearance X0 changes. Therefore, it is not necessary to change the filter characteristics even when the clearance X0 changes. Therefore, by providing one low-pass filter 50, it is possible to suppress the free running distance until braking of the electric brake 100 without adjusting the clearance X0, and the impact force when the piston 28 contacts the non-rotating disk 4. Can be relaxed.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The electric brake according to the present invention is not limited to one that brakes wheels for an aircraft, but can be used for other types of electric brakes such as those provided in other vehicles and machines, and caliper types.

DESCRIPTION OF SYMBOLS 100 Electric brake 3 Torque tube 4 Non-rotating disk 6 Rotating disk 21 Electric motor 24 Deceleration mechanism 27 Ball screw / nut mechanism 28 Piston 30 Controller 31 Pedal input sensor 32 Brake command / piston stroke conversion part 33 Pedal input determination part 34 Clearance measurement part 50 Low-pass filter

Claims (5)

A rotating disk that rotates with the wheels;
A wheel control means supported non-rotatably with respect to the airframe and displaceable toward the rotating disk;
A piston capable of advancing and retracting toward the wheel control means;
An electric actuator for linearly moving the piston;
A controller for controlling the operation of the electric actuator;
A braking command device that is operated by a pilot and outputs a braking command to the controller based on the operation;
An electric brake that generates a braking torque by the electric actuator pressing the wheel control means toward the rotating disk via the piston;
The controller is
Clearance storage means for storing a clearance between the piston and the wheel control means;
Operation detecting means for detecting whether or not the braking command device has been operated;
When the operation detecting means detects an operation of the braking command device, a piston abutting means for emitting a signal for moving the piston toward the wheel control means by the clearance stored in the clearance storage means;
A speed reduction means for processing a signal from the piston abutting means and outputting a first control signal of a first-order lag system for decelerating the piston before the piston abuts on the wheel restraining means;
A brake command for calculating an operating stroke of the piston after the piston abuts against the wheel control unit based on a braking command output by the braking command device, and outputting a second control signal corresponding to the operating stroke・ Piston stroke conversion part;
An electric adder that adds and outputs the first control signal and the second control signal, and controls the electric actuator based on the signal output from the adder. .   The electric brake according to claim 1, wherein the wheel control means is a non-rotating disk.   3. The electric brake according to claim 1, wherein the operation detection unit detects that the braking command device is operated by a minimum amount capable of outputting a braking command. 4. The electric brake according to claim 2 , wherein the clearance storage means stores a clearance between the piston and the non-rotating disk after the previous brake release.   The electric brake according to any one of claims 1 to 4, wherein the deceleration means is a low-pass filter.

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