JP2015168311A - Electric brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric brake device capable of reducing the power consumption of the electric brake device while eliminating the influence on a brake feeling, and suppressing the abrasion of a component to which a friction force is applied.SOLUTION: An electric brake device comprises: an electric motor 2; a brake rotor; a brake member pressed against the brake rotor; a transmission mechanism for converting the rotational motion of the electric motor 2 into the operation of the brake member; and a motor control part 35. The motor control part 35 is provided with operation frequency limiting means 40. When a brake force command value given from brake force command means becomes larger, the operation frequency limiting means 40 lowers a limit frequency or reduces a response ratio which is the magnitude of a motor operation command value for a fluctuation component.

Description

  The present invention relates to an electric brake device, and relates to a technique for reducing power consumption.

Conventionally, the following are proposed as an electric brake device.
1. By depressing the brake pedal, the rotational motion of the motor is converted into a linear motion via a linear motion mechanism, and the braking force is applied by pressing the brake pad against the brake disc (Patent Document 1).
2. An electric linear actuator using a planetary roller screw mechanism has been proposed (Patent Document 2).

JP-A-6-327190 JP 2006-194356 A

In the electric brake devices 1 and 2 described above, hysteresis loss due to friction of the screw mechanism occurs with respect to fluctuations in the braking force. For example, even if the driver of the vehicle repeats the depression (operation) and release of the brake pedal within a short time and the depression amount (operation amount) of the brake pedal is apparently constant, Hysteresis loss occurs due to fluctuations in braking force due to external factors such as riding up.
FIG. 12 is a diagram for explaining the concept of hysteresis loss of the electric brake device. The normal efficiency characteristic A1 when increasing the braking force is different from the reverse efficiency characteristic A2 when decreasing the braking force, mainly due to the influence of frictional force such as a screw mechanism of a linear motion mechanism.

  For example, the braking force when the driver of the vehicle depresses the brake pedal and generates a desired input torque T1 in the electric motor is defined as the braking force F. The operator further depresses the brake pedal, and the braking force increases along the positive efficiency characteristic A1 along the arrow L1. When the input torque T2 is reached, a braking force of F + ΔF is applied. Here, when the operator releases the brake pedal, the input torque decreases along the arrow L2 while maintaining the braking force of F + ΔF. When this input torque reaches the reverse efficiency characteristic A2, the braking force decreases along the reverse efficiency characteristic A2 along the arrow L3. When the brake pedal is stepped on again when the braking force F decreases, the input torque increases along the arrow L4 while maintaining the braking force F, and reaches the positive efficiency characteristic A1.

  The hysteresis loss when the unit braking force is increased or decreased is an area S surrounded by the hysteresis lines L1 to L4. One cycle from the hysteresis lines L1 to L4 is one fluctuation cycle, and the total number of hysteresis losses increases as the number of fluctuation cycles per unit time of the braking force increases. Even if the increase / decrease value ΔF of the brake force is the same, the area S increases as the brake force increases, so the hysteresis loss increases. The increase in hysteresis loss increases the power consumption of the electric brake device. Further, since the hysteresis loss is mainly caused by the frictional force, there is a possibility that the wear of the parts on which the frictional force acts is increased.

  An object of the present invention is to provide an electric brake device capable of reducing the power consumption of the electric brake device while eliminating the influence on the brake feeling, and suppressing the wear of parts to which a frictional force acts.

The electric brake device according to the present invention includes an electric motor 2, a brake rotor 6, a brake member 7 pressed against the brake rotor 6, and a transmission mechanism 4 that converts the rotational motion of the electric motor 2 into the operation of the brake member 7. A brake force command means 31a for generating a brake force command value from an operation amount of the brake operation means 32, a brake force estimation means 42 for obtaining an estimated value of a brake force for pressing the brake member 7 against the brake rotor 6, In an electric brake device comprising: a control device 35 that outputs a motor operation command value to the electric motor 2 in accordance with a brake force command value and the estimated value;
The control device 35 restricts an operating frequency, which is a frequency for changing the motor operation command value per unit time in accordance with a fluctuation component of one or both of the brake force command value and the estimated value, to a limit frequency or less. Or an operating frequency limiting means 40 for reducing a response ratio, which is a ratio of the magnitude of the motor operation command value to the fluctuation component, from a normal response ratio,
The operating frequency limiting means 40 is characterized in that, as the brake force command value given from the brake force command means 31a is larger, the limit frequency is lowered or the response ratio is made smaller.
The brake force estimating means 42 may be means for detecting a brake force.

  According to this configuration, when the driver of the vehicle repeats the operation and release of the brake operation means 32 within a short period of time, for example, the positive efficiency characteristic and the braking force that increase the braking force due to the influence of the frictional force of the transmission mechanism 4 and the like. Hysteresis loss is generated based on the difference from the reverse efficiency characteristic that reduces the. Even if the increase / decrease value of the brake force is the same, the greater the brake force, the larger the area surrounded by the hysteresis line, so the hysteresis loss increases.

Therefore, the operating frequency limiting means 40 of the control device 35 decreases the limiting frequency or decreases the response ratio as the braking force command value increases. For example, when a braking force command value with a fluctuation cycle is input to the operating frequency limiting means 40 in the high braking force region, the operating frequency limiting means 40 lowers the limiting frequency or decreases the response ratio. . Thereby, since the number of fluctuation cycles per unit time of the braking force can be suppressed, it is possible to reduce the total hysteresis loss.
In this way, the power consumption of the electric brake device can be reduced by limiting the operating frequency in the high braking force region where the hysteresis loss is large to be equal to or lower than the limit frequency or reducing the response ratio. Further, by reducing the hysteresis loss due to the frictional force, it is possible to suppress the wear of the component on which the frictional force acts and to improve the durability of this component.
Although limiting the operating frequency or reducing the response ratio is accompanied by a decrease in the responsiveness of the electric brake device, the high braking force region generates a high deceleration G in a vehicle equipped with the electric brake device. It is considered that it is difficult to feel a sense of incongruity in the brake feeling that accompanies a decrease in the responsiveness of the electric brake device. For this reason, as the brake force command value is larger, the power consumption can be reduced without making the brake feeling uncomfortable by limiting the operating frequency or reducing the response ratio. .

The operating frequency limiting means 40 may be a low-pass filter that lowers the limiting frequency that limits fluctuations in the braking force command value as the braking force command value increases. The brake force command unit 31a generates a brake force command value in accordance with, for example, a sensor output that varies depending on the operation amount of the brake operation unit 32. The amount of operation of the brake operation means 32 is not only the amount of operation due to an internal factor such as a vehicle operator repeating the operation and release of the brake operation means 32 within a short time, but also the operation amount of the brake operation means 32. Includes an operation amount due to an external factor such as a vehicle climbing a step even if it is constant in appearance.
According to this configuration, for example, the process of lowering the limit frequency can be performed by the low-pass filter provided in the subsequent stage of the braking force command unit 31a.

  The operating frequency limiting means 40 may be a low-pass filter that lowers the limiting frequency that limits the fluctuation component of the current command due to the voltage value converted from the braking force command value as the braking force command value increases. good. In this case, the operating frequency can be limited to the limit frequency with higher accuracy than filtering the fluctuation component of the brake force command value.

  The control device 35 has a function of feedback-controlling the estimated value of the brake force estimated by the brake force estimating means 42 with respect to the brake force command value generated by the brake force command means 31a. The operating frequency limiting unit 40 may be a feedback gain adjusting unit that adjusts the feedback gain. In this case, the feedback gain adjusting means adjusts the feedback gain in accordance with the brake force command value generated by the brake force command means 31a. Therefore, the hysteresis loss can be reduced by adjusting the followability such as the response ratio to the fluctuation component of the brake force command value, that is, the gain.

The operating frequency limiting means 40 may decrease the limiting frequency or decrease the response ratio only when the brake force command value exceeds a threshold value.
The threshold value is based on, for example, whether or not the vehicle operator feels uncomfortable with the brake feeling by repeating the depression (operation) and release of the brake pedal within a short time when the brake force is changed in magnitude. It is determined as
If the limit frequency is lowered when the brake force command value is less than or equal to the threshold value, the driver of the vehicle may feel uncomfortable with the brake feeling. Therefore, when the braking force command value exceeds the threshold value, the operating frequency limiting means 40 lowers the limiting frequency or decreases the response ratio, thereby further reducing the uncomfortable feeling of the brake feeling. Power consumption can be reduced.

  The electric brake device according to the present invention includes an electric motor, a brake rotor, a brake member pressed against the brake rotor, a transmission mechanism that converts the rotational motion of the electric motor into an operation of the brake member, and an operation of the brake operation means. Brake force command means for generating a brake force command value from the amount, brake force estimation means for obtaining an estimated value of the brake force that presses the brake member against the brake rotor, and the brake force command value and the estimated value according to An electric brake device including a control device that outputs a motor operation command value to an electric motor, wherein the motor operation is performed by the control device according to a fluctuation component of one or both of the brake force command value and the estimated value. The operating frequency, which is the frequency that fluctuates the command value per unit time, is below the limit frequency. An operating frequency limiting means for reducing a response ratio, which is a ratio or a ratio of the magnitude of the motor operation command value with respect to the fluctuation component, to be lower than a normal response ratio, is provided from the brake force command means. As the brake force command value to be generated is larger, the limit frequency is lowered or the response ratio is made smaller. For this reason, it is possible to reduce the power consumption of the electric brake device while eliminating the influence on the brake feeling, and to suppress the wear of parts on which the frictional force acts.

It is sectional drawing of the electric brake device which concerns on embodiment of this invention. It is an expanded sectional view of the deceleration mechanism of the same electric brake device. It is a block diagram of a control system of the electric brake device. It is a figure which shows the correlation of the brake force with respect to increase / decrease in the input torque of the same electric brake device. It is a figure which shows the relationship between an operating frequency and a gain in each brake force area | region. It is a block diagram which shows an example of the operating frequency limiting means of the same electric brake device. It is a block diagram which shows the example of the operating frequency limiting means of the electric brake device which concerns on other embodiment of this invention. It is a block diagram which shows the example of the operating frequency limiting means of the electric brake device which concerns on further another embodiment of this invention. It is a figure which respectively shows the response waveform of the brake force with respect to the brake force command value in the time domain of the electric brake device. It is a figure which shows the hysteresis loss of the braking force of FIG. It is a block diagram which shows the example of the operating frequency limiting means of the electric brake device which concerns on further another embodiment of this invention. It is a figure explaining the concept of the hysteresis loss of an electric brake device.

An electric brake device according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the electric brake device includes a housing 1, an electric motor 2, a speed reduction mechanism 3 that decelerates the rotation of the electric motor 2, a linear motion mechanism 4 that is a transmission mechanism, and a lock mechanism 5. The brake rotor 6, the brake pad 7 as a brake member, the ECU 31, and the inverter device 33 are included. A base plate 8 extending radially outward is provided at the open end of the housing 1, and the electric motor 2 is supported on the base plate 8. In the housing 1 is incorporated a linear motion mechanism 4 that applies a braking force to the brake rotor 6, in this example, the disk rotor, by the output of the electric motor 2. The opening end of the housing 1 and the outer surface of the base plate 8 are covered with a cover 10.

The linear motion mechanism 4 will be described.
The linear motion mechanism 4 is a mechanism that converts the rotational motion output from the speed reduction mechanism 3 into a linear motion and causes the brake pad 7 to abut against and separate from the brake rotor 6. The linear motion mechanism 4 includes a slide member 11, a bearing member 12, an annular thrust plate 13, a thrust bearing 14, rolling bearings 15 and 15, a rotating shaft 16, a carrier 17, and sliding bearings 18 and 19. And have. A cylindrical slide member 11 is supported on the inner peripheral surface of the housing 1 so as to be prevented from rotating and movable in the axial direction. On the inner peripheral surface of the slide member 11, a spiral protrusion 11 a that protrudes a predetermined distance radially inward and is formed in a spiral shape is provided. A plurality of planetary rollers 20 to be described later mesh with the spiral protrusion 11a.

  A bearing member 12 is provided on one end side in the axial direction of the slide member 11 in the housing 1. The bearing member 12 has a flange portion extending radially outward and a boss portion. Rolling bearings 15 and 15 are fitted into the boss portions, and a rotary shaft 16 is fitted to the inner ring inner surface of each of the bearings 15 and 15. Therefore, the rotating shaft 16 is rotatably supported by the bearing member 12 via the bearings 15 and 15.

  A carrier 17 is provided on the inner periphery of the slide member 11 so as to be rotatable about the rotary shaft 16. The carrier 17 includes disks 17a and 17b that are arranged to face each other in the axial direction. The disk 17b close to the bearing member 12 may be referred to as an inner disk 17b, and the disk 17a may be referred to as an outer disk 17a. Of the one disk 17a, a side surface facing the other disk 17b is provided with an interval adjusting member 17c protruding in the axial direction from the outer peripheral edge portion on this side surface. A plurality of spacing adjusting members 17c are arranged at equal intervals in the circumferential direction in order to adjust the spacing between the plurality of planetary rollers 20. The discs 17a and 17b are integrally provided by the distance adjusting member 17c.

  The inner disk 17b is supported by a slide bearing 18 fitted between the inner shaft 17b and the inner shaft 17b so as to be rotatable and movable in the axial direction. A shaft insertion hole is formed at the center of the outer disk 17a, and a slide bearing 19 is fitted in the shaft insertion hole. The outer disk 17a is rotatably supported on the rotary shaft 16 by a slide bearing 19. A washer that receives a thrust load is fitted to the end of the rotating shaft 16, and a retaining ring for preventing the washer from coming off is provided.

  The carrier 17 is provided with a plurality of roller shafts 21 at intervals in the circumferential direction. Both end portions of each roller shaft 21 are supported across the disks 17a and 17b. That is, the discs 17a and 17b are formed with a plurality of shaft insertion holes each having a long hole, and both end portions of the roller shafts 21 are inserted into the shaft insertion holes, and the roller shafts 21 are supported so as to be movable in the radial direction. The An elastic ring 22 that urges the roller shafts 21 radially inward is stretched around the plurality of roller shafts 21.

A planetary roller 20 is rotatably supported on each roller shaft 21, and each planetary roller 20 is interposed between the outer peripheral surface of the rotary shaft 16 and the inner peripheral surface of the slide member 11. Each planetary roller 20 is pressed against the outer peripheral surface of the rotating shaft 16 by the urging force of the elastic ring 22 spanned across the plurality of roller shafts 21. As the rotating shaft 16 rotates, each planetary roller 20 that contacts the outer peripheral surface of the rotating shaft 16 rotates due to contact friction. On the outer peripheral surface of the planetary roller 20, a spiral groove that meshes with the spiral protrusion 11a of the slide member 11 is formed.
A washer and a thrust bearing (both not shown) are interposed between the inner disk 17b of the carrier 17 and one axial end of the planetary roller 20. In the housing 1, an annular thrust plate 13 and a thrust bearing 14 are provided between the inner disk 17 b and the bearing member 12.

The deceleration mechanism 3 will be described.
As shown in FIG. 2, the speed reduction mechanism 3 is a mechanism that transmits the rotation of the electric motor 2 at a reduced speed to the output gear 23 fixed to the rotation shaft 16, and includes a plurality of gear trains. In this example, the speed reduction mechanism 3 is fixed to the end of the rotary shaft 16 by sequentially reducing the rotation of the input gear 24 attached to the rotor shaft 2 a of the electric motor 2 by the gear trains 25, 26 and 27. Transmission to the output gear 23 is possible.

The lock mechanism 5 will be described.
The lock mechanism 5 is configured to be switchable between a locked state in which the braking force slack operation of the linear motion mechanism 4 is prevented and an allowed unlocked state. The deceleration mechanism 3 is provided with a lock mechanism 5. The lock mechanism 5 is a casing (not shown), a lock pin 29, an urging means (not shown) for urging the lock pin 29 to an unlocked state, and an actuator for switching and driving the lock pin 29. And a linear solenoid 30. The casing is supported by the base plate 8, and the base plate 8 is formed with pin holes that allow the lock pins 29 to advance and retreat.

  By causing the lock pin 29 to advance by the linear solenoid 30 and engaging with a locking hole (not shown) formed in the output-side intermediate gear 28 in the gear train 26, prohibiting the rotation of the intermediate gear 28, Set to locked state. When the linear solenoid 30 is turned off, the lock pin 29 is retracted into the casing by the urging force of the urging means to be detached from the locking hole, and the rotation of the intermediate gear 28 is allowed, whereby the lock mechanism 5 Is unlocked.

  FIG. 3 is a block diagram of a control system of the electric brake device. As the ECU 31 of this electric brake device, for example, an electric control unit that controls the entire vehicle is applied. The ECU 31 has a brake force command means 31a. The brake force command means 31a generates a brake force command value according to the output of the sensor 32a that changes according to the amount of operation of the brake pedal as the brake operation means 32. Output. The amount of operation is not only the amount of operation due to an internal factor such as the vehicle operator repeating the operation and release of the brake operation means 32 within a short time, but the operation amount of the brake operation means 32 is apparently constant. Even if it exists, the operation amount by external factors, such as a vehicle climbing on a level | step difference, is also included.

  An inverter device 33 is connected to the ECU 31, and the inverter device 33 includes a brake force estimating means 42 for obtaining an estimated value of a brake force that presses the brake pad 7 against the brake rotor, and a power circuit portion 34 provided for each electric motor 2. And a motor control unit 35 which is a control device for controlling the power circuit unit 34. The brake force estimation means 42 obtains an estimated value of the corresponding brake force by calculation from the output of the sensor 32a that changes according to the operation amount of the brake operation means 32 and the motor current detected by the current detection means 38. In addition to this, the brake force estimating means 42 may estimate the brake force from a load in the vehicle traveling direction detected by a load sensor provided on a wheel bearing (not shown) or the like. The relationship between the sensor output, the motor current, and the estimated value of the braking force is stored in advance in a relationship setting unit determined by experiments or the like.

  The motor control unit 35 includes a computer, a program executed on the computer, and an electronic circuit. The motor control unit 35 converts the current command into a current command based on a voltage value according to the braking force command value given from the ECU 31 and the estimated value of the braking force estimated by the braking force estimation means 42, and converts the current command into the power circuit unit. 34 is given as a motor operation command value to the PWM control unit 34a. In addition, the motor control unit 35 has a function of outputting information such as detection values and control values related to the electric motor 2 to the ECU 31.

  The power circuit unit 34 includes an inverter 34b that converts the DC power of the power source 36 into three-phase AC power used for driving the electric motor 2, and a PWM control unit 34a that controls the inverter 34b. The electric motor 2 is composed of a three-phase synchronous motor or the like. The inverter 34b is composed of a plurality of semiconductor switching elements (not shown), and the PWM controller 34a performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

  The motor control unit 35 as a control device has a motor drive control unit 37 as a basic control unit. The motor drive control unit 37 converts the motor command into a current command according to the brake force command value given from the brake force command unit 31a and the estimated value given from the brake force estimation unit 42, and sends the current command to the PWM control unit 34a. Give the operation command value. The motor drive control unit 37 includes, for example, a controller 43, an amplifier 44, and an operating frequency limiting unit 40.

  The controller 43 obtains a motor current to be passed from the inverter 34b to the electric motor 2 from the current detection means 38 and performs current feedback control on the restricted brake force command value output from the operating frequency restriction means 40. The current command converted and output by the controller 43 is followed by a gain determined by the amplifier 44 which is an amplifier circuit, and is output as a motor operation command value. Further, the motor drive control unit 37 obtains the rotation angle of the rotor of the electric motor 2 from the rotation angle sensor 39, and gives a current command to the PWM control unit 34a so that efficient motor drive according to the rotor rotation angle can be performed. .

  The operating frequency limiting means 40 reduces the operating frequency, which is a frequency that fluctuates the motor operating command value per unit time in accordance with the fluctuation component of one or both of the braking force command value and the estimated value, to a frequency lower than the limiting frequency. It is means for limiting or reducing a response ratio, which is a ratio of the magnitude of the motor operation command value to the fluctuation component, below the normal response ratio.

  Here, FIG. 4 is a diagram showing the correlation of the braking force with the increase or decrease of the input torque of the electric brake device. The normal efficiency characteristic A1 when increasing the braking force and the inverse efficiency characteristic A2 when decreasing the braking force are mainly different in the inclination of the braking force with respect to the input torque due to the influence of the frictional force of the linear motion mechanism or the like. . As described above, the hysteresis loss when the unit braking force is increased or decreased is the area S surrounded by the hysteresis lines L1 to L4. One cycle from the hysteresis lines L1 to L4 is one fluctuation cycle, and the total number of hysteresis losses increases as the number of fluctuation cycles per unit time of the braking force increases. Even if the increase / decrease value ΔF of the brake force is the same, the area S increases as the brake force increases, so the hysteresis loss increases.

  For example, assuming that both the normal efficiency characteristic A1 and the reverse efficiency characteristic A2 are linear, the hysteresis loss Ph per unit brake force fluctuation cycle is proportional to the brake force. For the same braking force and braking force fluctuation, the hysteresis loss Ph is proportional to the number of fluctuation cycles per unit time, that is, the operating frequency.

  Therefore, as shown in FIG. 3, the motor control unit 35, which is a control device, lowers the limit frequency as the brake force command value increases. For example, in a high brake force region, when a braking force command value with a fluctuation cycle is input to the operating frequency limiting unit 40, the operating frequency limiting unit 40 limits the limiting frequency to a low level. Thereby, since the number of fluctuation cycles per unit time of the braking force can be suppressed, it is possible to reduce the total hysteresis loss. The high braking force region is a condition under which high deceleration G (for example, gravitational acceleration of 0.4 G or more) is generated in the vehicle.

  Thus, the power consumption of this electric brake device can be reduced by limiting the operating frequency in the high braking force region where the hysteresis loss is large. Further, by reducing the hysteresis loss due to the frictional force, it is possible to suppress wear of the linear motion mechanism or the like on which the frictional force acts, and to improve the durability of the linear motion mechanism or the like.

  FIG. 5 is a diagram illustrating the relationship between the operating frequency and the gain in each braking force region. In the braking force regions Fa, Fb, Fc having the relationship of Fa> Fb> Fc, the operating frequency is cut so that the braking force response attenuates with respect to the frequency component of the braking force command value as the braking force increases. Either one or both of the off-frequency and the attenuation rate are changed. However, since a steady deviation is obtained when the gain is reduced with respect to the direct current component, the frequency 0 Hz or the vicinity thereof may have a characteristic in which the braking force response is not attenuated with respect to the frequency component of the braking force command value.

  FIG. 6 is a block diagram showing an example of the operating frequency limiting means 40 provided in the motor control unit 35 of this electric brake device. This will be described with reference to FIG. The operating frequency limiting means 40 is provided after the brake force command means 31a and the brake force estimation means 42, and is generated by the brake force command value generated by the brake force command means 31a and / or the brake force estimation means 42. This is a variable low-pass filter that cuts fluctuation components above the limit frequency of the estimated brake force value. The low-pass filter lowers the limit frequency as the brake force command value (estimated value) increases. The fluctuation component of the brake force command value (estimated value) is suppressed by a low-pass filter and is input to the controller 43, where it is converted into a current command and current feedback control is performed. The current command from the controller 43 is input to the amplifier 44, followed by a predetermined gain, and output as a motor operation command value. For example, the gain is stored in the storage unit 41 and is read out from the storage unit 41 at the time of calculation.

  Thereafter, as shown in FIG. 3, the motor control unit 35 gives the current command (motor operation command value) to the PWM control unit 34a. The PWM control unit 34a performs pulse width modulation on the given current command, and gives an on / off command to each of the semiconductor switching elements of the inverter 34b.

  As described above, the power consumption of the electric brake device can be reduced by limiting the operating frequency in the high braking force region where the hysteresis loss is large to the limit frequency or less. Further, by reducing the hysteresis loss due to the frictional force, it is possible to suppress wear of the linear motion mechanism or the like on which the frictional force acts, and to improve the durability of the linear motion mechanism or the like.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  The operating frequency limiting means 40 shown in FIG. Further, a low-pass filter is provided as the operating frequency limiting means 40, which inputs a braking force command value to the controller 43 and lowers a limiting frequency that limits the fluctuation component of the current command due to the voltage value output from the controller 43. In this case, the operating frequency can be limited to the limit frequency with higher accuracy than filtering the fluctuation component of the brake force command value.

  As shown in FIG. 8, the gain of the controller 43 may be adjusted. In this example, the control device has a function of feedback-controlling the braking force estimated by the braking force estimation means 42 (FIG. 3) with respect to the braking force command value. The operating frequency limiting unit 40 in this configuration is a feedback gain adjusting unit that adjusts the feedback gain. The feedback gain is, for example, a gain by PI control or PID control. In this case, the feedback gain adjusting means adjusts the feedback gain corresponding to the brake force command value generated by the brake force command means 31a (FIG. 3). Therefore, the hysteresis loss can be reduced by adjusting the followability to the fluctuation frequency, that is, the gain to be lower than the normal response ratio.

  FIG. 9 is a diagram showing response waveforms of the brake forces F1 and F2 with respect to the brake force command values Ft1 and Ft2 in the time domain of the electric brake device. In the figure, the brake force command values Ft1 and Ft2 have the same amplitude and frequency but different absolute values. For these brake force command values Ft1 and Ft2, response waveforms output as brake forces for pressing the brake pads against the brake rotor by applying the operating frequency limiting means 40 (FIG. 3) are brake forces F1 and F2, respectively. is there. The operating frequency limiting means 40 (FIG. 3) attenuates the frequency component at the operating frequency of the braking force F2 having a high load compared to the braking force F1 having a low load.

  FIG. 10 is a diagram showing hysteresis loss of the braking forces F1 and F2 of FIG. As described above, unlike the normal efficiency characteristic A1 when increasing the braking force and the reverse efficiency characteristic A2 when decreasing the braking force, the increase / decrease value of the braking force is generally the same as the braking force increases. Although the hysteresis loss increases, the hysteresis loss of the brake force F2 having a high load can be reduced by applying the operating frequency limiting means 40 (FIG. 3) than the hysteresis loss of the brake force F1 having a low load. Can do.

  As shown in FIG. 11, a configuration in which a process of reducing the operating frequency is executed and a case where the process is not executed may be switched. As shown in FIGS. 11 and 3, the operating frequency limiting means 40 of this configuration includes a determination unit 40a that determines whether or not the brake force command value exceeds a threshold value, and the determination unit 40a determines the brake force command value. And an execution unit that limits the operating frequency when it is determined that the threshold value is exceeded. The execution unit is a part other than the determination unit 40 a in the operating frequency limiting unit 40.

  This execution unit is realized by a switch or the like that switches a path K1 through which the brake force command value passes through the low-pass filter and a path K2 through which the low-pass filter is bypassed. The threshold value is based on, for example, whether or not the vehicle operator feels uncomfortable with the brake feeling by repeating the depression (operation) and release of the brake pedal within a short time when the brake force is changed in magnitude. It is determined as The threshold value is rewritably stored in the storage means 41 (FIG. 3). When the braking force exceeds a threshold value, the execution unit switches the braking force command value to the path K1 passing through the low-pass filter and executes the restriction of the operating frequency, so that this electric brake can be performed without causing uncomfortable feeling of brake feeling. The power consumption of the apparatus can be reduced.

When the vehicle equipped with the electric brake has an anti-lock brake system (abbreviated as ABS), the control device receives the operation signal from the ABS and limits the operation frequency by the operation frequency limiting means while the ABS is operating. Is configured not to execute. In this case, the braking distance of the vehicle can be shortened by preventing the responsiveness of the electric brake device from being lowered under the condition that the ABS operates.
In each said embodiment, although the electric brake device is applied to the disc brake, it is not limited only to a disc brake. The electric brake device may be applied to the drum brake.

2 ... Electric motor 4 ... Linear motion mechanism 6 ... Brake rotor 7 ... Brake pad (brake member)
31a ... brake force command means 35 ... motor control section (control device)
40 ... Operating frequency limiting means 42 ... Brake force estimating means

Claims (5)

A brake force command value is generated from an operation amount of an electric motor, a brake rotor, a brake member pressed against the brake rotor, a transmission mechanism for converting the rotational motion of the electric motor into an operation of the brake member, Braking force command means for performing braking force estimation means for obtaining an estimated value of braking force for pressing the brake member against the brake rotor, and a motor operation command value for the electric motor in accordance with the brake force command value and the estimated value. In an electric brake device including a control device for outputting,
The control device restricts an operating frequency, which is a frequency for changing the motor operation command value per unit time according to a fluctuation component of one or both of the brake force command value and the estimated value, to a limit frequency or less. Or an operating frequency limiting means for reducing a response ratio, which is a ratio of the magnitude of the motor operation command value to the fluctuation component, from a normal response ratio;
The operating frequency limiting means lowers the limiting frequency or decreases the response ratio as the brake force command value given from the brake force command means increases.   2. The electric brake device according to claim 1, wherein the operating frequency limiting means is a low-pass filter that lowers the limit frequency that limits fluctuations in the brake force command value as the brake force command value increases. .   2. The electric brake device according to claim 1, wherein the operating frequency limiting means limits the fluctuation component of the current command due to the voltage value converted from the brake force command value as the brake force command value increases. Electric brake device that is a low-pass filter that lowers   2. The electric brake device according to claim 1, wherein the control device feedback-controls an estimated value of the brake force estimated by the brake force estimating unit with respect to a brake force command value generated by the brake force command unit. And the operating frequency limiting means is a feedback gain adjusting means for adjusting a feedback gain.   5. The electric brake device according to claim 1, wherein the operating frequency limiting means lowers the limiting frequency or sets the response ratio only when the brake force command value exceeds a threshold value. Electric brake device to make it smaller.

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