JP2021066406A - Electric brake control device - Google Patents

Abstract

To acquire the highly reliable 0-point position of a pressing member in an electric brake.SOLUTION: In a present electric brake control device, while the position of the pressing member when an actual load which is the detection value of a load sensor becomes smaller than a threshold is acquired as a 0-point position, the electric brake is controlled in a different mode between a case where the actual load is large and a case where the actual load is small when a normal-time target load becomes smaller than a reference target load. For example, in a case where the actual load is large when the normal-time target load becomes smaller than the reference target load, and a deviation between the actual load and the normal-time target load is large, both the reduction gradient of the actual load and the change gradient of the position of the pressing member become large, so that it becomes difficult to accurately acquire the 0-point position. In contrast, in the present electric brake control device, the reduction gradient of the actual load is suppressed, and a change in the position of the pressing member is also suppressed. As a result, it becomes possible to accurately acquire the 0-point position which is the position of the pressing member when the actual load becomes smaller than the threshold, so that it is possible to acquire the highly reliable 0-point position.SELECTED DRAWING: Figure 5

Description

The present invention relates to the zero point position of the electric brake.

Patent Document 1 states that the non-restoring amount of the brake pad (elasticity that does not immediately return when the pressing force applied to the brake pad is removed) from the position when the load reduction gradient of the pressing member becomes gentler than the set gradient. It is described that the position on the forward side is set to the 0 point position by the amount determined by (referring to the amount of deformation).
In Patent Document 2, the 0-point offset amount of the load sensor is acquired based on the detected value of the load sensor when the pressing member is in the retracted end position, and the 0-point offset amount is taken into consideration in the control of the electric brake. It is stated that. As a result, the pressing force of the friction pad against the rotating body of the brake can be accurately obtained, and the control accuracy of the electric motor can be improved.

Japanese Unexamined Patent Publication No. 2007-147081 Japanese Unexamined Patent Publication No. 2000-21375

An object of the present invention is to obtain a highly reliable zero-point position of a pressing member of an electric brake.

Means, actions and effects to solve problems

In the electric brake control device according to the present invention, the position of the pressing member when the actual load, which is the detected value of the load sensor, becomes smaller than the threshold value is acquired as the 0 point position, but the normal target load is the reference target. The electric brake is controlled in different modes depending on whether the actual load is larger or smaller than the load.
For example, when the actual load is large when the normal target load is smaller than the reference target load and the deviation between the actual load and the normal target load is large, the decrease gradient of the actual load is also the change gradient of the position of the pressing member. Also becomes large, so it becomes difficult to accurately acquire the 0-point position. On the other hand, in this electric brake control device, since the decrease gradient of the actual load is suppressed, the change in the position of the pressing member is also suppressed. As a result, it is possible to accurately acquire the 0-point position, which is the position of the pressing member when the actual load becomes smaller than the threshold value, and it is possible to acquire the highly reliable 0-point position.

It is a figure which conceptually shows the periphery of the electric brake control device which concerns on one Embodiment of this invention. It is sectional drawing of the main part of the electric brake which is the control target of the said electric brake control device. (3a) It is a figure which conceptually shows the change of the target load and the actual load of the said electric brake. (3b) It is a figure which conceptually shows the change of the stroke of a pressing member. (3c) It is a figure which shows the change of a motor current conceptually. (4a) It is a figure which conceptually shows the change of the target load and the actual load of the said electric brake. (4b) It is a figure which conceptually shows the change of the stroke of a pressing member. (4c) It is a figure which shows the change of a motor current conceptually. (5a) It is a figure which conceptually shows the change of the target load and the actual load of the said electric brake. (5b) It is a figure which conceptually shows the change of the stroke of a pressing member. (5c) It is a figure which shows the change of a motor current conceptually. It is a flowchart which shows the 0 point position acquisition program stored in the storage part of the motor ECU of the electric brake control device. (7a) It is a figure which conceptually shows the change of the target load and the actual load of the conventional electric brake. (7b) It is a figure which conceptually shows the change of the stroke of a pressing member. (8a) It is a figure which conceptually shows the change of the target load and the actual load of the conventional electric brake. (8b) It is a figure which conceptually shows the change of the stroke of a pressing member.

Hereinafter, a vehicle brake system including an electric brake control device as an embodiment of the present invention will be described.

As shown in FIG. 1, the vehicle brake system includes an electric brake 8 provided on at least one of a plurality of wheels of the vehicle, an electric brake control device 6 for controlling at least one electric brake 8, and the like.
The electric brake 8 is a disc brake, which is (a) a rotor 30 that can rotate integrally with a wheel, and (b) a friction pad as a pair of friction members that are held by mounting brackets (not shown) and are located on both sides of the rotor 30. 32, 34, (c) Pressing device 36 and the like are included. The pressing device 36 includes (i) a caliper 40 that straddles the rotor 30 and is movably held in a mounting bracket in a direction parallel to the rotation axis of the rotor 30, and (ii) an electric actuator 42 that is held by the caliper 40. ..

As shown in FIG. 2, the electric actuator 42 has (a) a housing 44 and (b) a housing 44 in the axial direction of the electric actuator 42 (reference numeral L indicates an axis. The axis L is parallel to the rotation axis of the rotor 10. A pressing member 46 that is movable and non-rotatable, (c) a drive source having an electric motor 48 and a speed reducer 50, and (d) motion transmission that transmits the output of the drive source to the pressing member 46. The mechanism 52 and the like are included.

The pressing member 46 extends in the axial direction, and its front end portion is located so as to face the friction pad 32. Further, an engaging hole extending in the axial direction is formed in the central portion of the rear portion of the pressing member 46, and a female screw portion 46s is formed on the inner peripheral surface of the engaging hole.

The electric motor 48 includes a plurality of coils 60 constituting the stator, a rotary drive shaft 62 having a generally hollow cylindrical shape, and the like. The rotation drive shaft 62 is held in the housing 44 via a bearing 63 so as to be rotatable around the axis L and immovable in the axial direction. Further, on the inner peripheral side of the rotation drive shaft 62, the rear portion of the pressing member 46 is fitted so as to be relatively movable and relatively rotatable in the axial direction. The rotation of the rotation drive shaft 62 is input to the speed reducer 50.

The speed reducer 50 is of a planetary gear type, and meshes with both the sun gear 64 that can rotate integrally with the rotary drive shaft 62, the ring gear 66 fixed to the housing 44, and the sun gear 64 and the ring gear 66. A plurality of planetary gears 68 revolving around the sun gear 64 (FIG. 3 shows one of the plurality of planetary gears 68) and a carrier 72 holding the plurality of planetary gears 68. The carrier 72 is integrally rotatably held on the output shaft 70. The carrier 72 is rotated along with the revolution of the planetary gear 68, and the output shaft 70 is rotated around the axis L. The speed reducer 50 reduces the rotational speed of the rotary drive shaft 62 and outputs the output shaft 70, and the rotary drive force of the rotary drive shaft 62 is boosted and output. The output shaft 70 of the speed reducer 50 (drive source) is the input shaft of the motion transmission mechanism 52. Therefore, hereinafter, it is referred to as an input shaft 70.

The input shaft 70 extends in the axial direction and is held in the housing 44 so as to be rotatable and immovable in the axial direction. A carrier 72 is integrally rotatably held at the rear portion of the input shaft 70, and a male screw portion 70s is formed at the outer peripheral portion of the front portion. The front portion of the input shaft 70 is inserted into the engaging hole at the rear portion of the pressing member 46, and the male screw portion 70s and the female screw portion 46s are screwed together. In this embodiment, the motion transmission mechanism 52, which is a screw mechanism, is configured by the male screw portion 70s of the input shaft 70, the female screw portion 46s of the pressing member 46, and the like. The operation transmission mechanism 52 also has a function as a motion conversion mechanism. The male threaded portion 46s and the female threaded portion 70s are trapezoidal threaded portions.

As described above, since the motion transmission mechanism 52 includes the trapezoidal screw portion, the reverse efficiency (input by the retreat of the pressing member 46) is compared with the positive efficiency (efficiency when the pressing member 46 is moved forward and backward by the rotation of the input shaft 70). Efficiency when rotating the shaft 70) becomes smaller.

The rotation of the input shaft 70 is converted into a linear motion and transmitted to the pressing member 46, whereby the pressing member 46 is moved in the axial direction. The forward rotation of the electric motor 48 causes the input shaft 70 to rotate in the forward direction, and the pressing member 46 to move forward. The pressing member 46 and the caliper 40 press the pair of friction pads 32 and 34 against the rotor 30, and the rotation of the wheels is suppressed. The electric brake 8 is operated, and an electric braking force, which is a braking force corresponding to the pressing force applied to the rotor 30, is applied to the wheels 6. Further, the rotation of the electric motor 48 in the opposite direction causes the input shaft 70 to be rotated in the backward direction, and the pressing member 46 to be retracted.

The return spring 90 is provided between the rear portion of the output shaft 70 and the housing 44. The return spring 90 applies a spring force (hereinafter, referred to as a spring force in the backward rotation direction) in a direction for rotating the output shaft 70 in the backward rotation direction of the output member 54 to the output shaft 70. The return spring 90 allows the output shaft 70 to rotate in the retracting direction and retracts the output member 54.

As shown in FIG. 1, the electric brake control device 6 includes a motor ECU 110 that controls the electric motor 48, a brake ECU 112 that controls the entire vehicle brake system (not shown), and the like. The motor ECU 110 and the brake ECU 112 are connected so that they can communicate with each other. The motor ECU 110 and the brake ECU 112 are mainly computers, and include an execution unit, a storage unit, an input / output unit, and the like, which are not shown.

The input / output unit of the brake ECU 112 includes a brake operation state acquisition device 120 that acquires an operation state of a brake operation member (not shown), a peripheral environment acquisition device 122 that acquires the environment around the vehicle, and a wheel speed that detects the rotation speed of the wheels. The sensor 124 and the like are connected. The brake ECU 112 acquires the target load F * based on the operation state of the brake operation member acquired by the brake operation state acquisition device 120, and the front object and its own vehicle (for the present vehicle) acquired by the surrounding environment acquisition device 122. The target load F * is acquired based on the relative positional relationship with the vehicle equipped with the brake system). In addition, the vehicle body speed is estimated based on the rotation speeds of the front, rear, left, and right wheels of the vehicle, and the slip state of each wheel is acquired. In some cases, the target load F * may be obtained based on the slip condition.
In this embodiment, the operating state of the brake operating member, the slip state of each wheel, and the like correspond to the state of the vehicle, and the relative positional relationship between the front object and the own vehicle corresponds to the state around the vehicle. In the brake ECU 112, the target load F * is acquired based on at least one of the state of the vehicle and the state around the vehicle.

The input / output section of the motor ECU 110 includes a rotation angle sensor 144 that detects the rotation angle of the electric motor 48, a load sensor 146 that detects the load applied to the pressing member 46, a current sensor 148 that detects the current flowing through the electric motor 48, and the like. Is connected, and the electric motor 48 is connected via the drive circuit 149. In this embodiment, the load sensor 146 detects the reaction force of the pressing force, which is the force with which the pressing member 46 pushes the rotor 30 via the friction members 32 and 34, and supports the input shaft 70 and the housing 44. A thrust bearing 150 provided between the plate 152 and the plate 152 detects an axial force applied to the support plate 152. Therefore, the load detected by the load sensor 146 corresponds to the pressing force.
In this embodiment, the connection between the sensor and the ECU and the connection between the ECUs mean connecting these by wire or wirelessly.

The brake ECU 112 transmits information representing the target load F * to the motor ECU 110. In the motor ECU 110, the actual load Fref, which is the detected value of the load sensor 146, is acquired by the brake ECU 110 and approaches the supplied target load F * (hereinafter referred to as the normal target load F *). The supply current to the electric motor 48 is determined based on the deviation which is the difference between the normal load and the normal target load F *, and the determined current is supplied. Further, as will be described later, when acquiring the 0 point position, the motor ECU 110 acquires the target load F0 * at the time of acquiring 0 points, and is based on the deviation between these actual load Fref and the target load F0 * at the time of acquiring 0 points. In some cases, a current is supplied to the electric motor 48. The current control to the electric motor 48 is called load control.

Further, the motor ECU 110 acquires the stroke (movement amount) of the pressing member 46 based on the rotation angle of the electric motor 48 detected by the rotation angle sensor 140, and acquires the position of the pressing member 46. The stroke of the pressing member 46 is the amount of movement of the pressing member 46 from the current 0-point position, and the position of the pressing member 46 is represented by a distance from the 0-point position. Then, the motor ECU 110 has a set target stroke (or set target position) in which the actual stroke (or actual position), which is the stroke (or position) of the pressing member 46 acquired based on the detection value of the rotation angle sensor 140, is predetermined. ), The supply current to the electric motor 48 is controlled based on the deviation (stroke deviation or position deviation) which is the difference between them. This control is called stroke control.

In this embodiment, when the normal target load F * is larger than the reference target load Fth * and there is an operation request for the electric brake 8 (sometimes referred to as braking ON), load control is performed and the normal target load is performed. Stroke control is performed after F * becomes equal to or less than the reference target load Fth * and braking is turned off. The reference target load Fth * is set to 0 in this embodiment.

Further, when the load is reduced (for example, when the electric brake 8 is released), the 0 point position of the pressing member 46 is acquired. The 0 point position is the position of the pressing member 46 when the actual load Fref is 0. In this embodiment, the position of the pressing member 46 when the actual load Fref becomes smaller than the first threshold value ΔF, which is the threshold value near 0, is set as the 0 point position.

For example, as shown in FIG. 3A, when the decreasing gradient of the normal target load F * is small, the delay of the actual load Fref with respect to the normal target load F * is small, and the actual load Fref to the normal target load The deviation, which is the value obtained by subtracting F *, becomes smaller. Further, as shown in FIGS. 3 (b) and 3 (c), when the normal target load F * is larger than 0, in other words, the braking is ON and the load control is performed, the actual load Fref is the first. It becomes smaller than the threshold value ΔF, and the 0 point position of the pressing member 46 is acquired.
When the decreasing gradient of the normal target load F * is small, the actual load Fref is often smaller than the first threshold value ΔF when the normal target load F * is larger than 0. When the target load F * becomes 0, the actual load Fref may become smaller than the first threshold value ΔF.
Hereinafter, such a change pattern such as a load will be referred to as pattern 1.

Then, after the normal target load F * becomes 0, the stroke control is performed, and the set target stroke is retracted from the 0 point position. As a result, dragging can be satisfactorily suppressed when braking is turned off.
Further, in the electric brake 8, for example, when it is predicted that the braking will be turned on in the near future, the pressing member 46 is advanced by the set target stroke by driving the electric motor 48. As a result, the pressing member 46 can be positioned at the 0 point position when the braking is turned on, and the operation delay of the electric brake 8 can be suppressed.

On the other hand, as shown in FIG. 7A, the decreasing gradient of the normal target load F * is not so large, but the actual load Fref when the normal target load F * becomes 0 is the first threshold value ΔF. If it is larger, the load control is switched to the stroke control before the 0 point position is acquired. Therefore, when the stroke control is performed, the 0 point position is acquired. However, when the normal target load F * becomes 0, the load applied to the electric motor 48 becomes very small, but since the pressing member 46 is located on the forward side from the 0 point position, the stroke control is started. The stroke deviation, which is the difference between the actual stroke at the time and the set target stroke, is large, and the electric motor 48 is rotated at a large rotational speed. Due to the sudden change in the rotational speed of the electric motor 48, noise is likely to occur, a counter electromotive force is generated in the electric motor 48, the pressing member 46 moves forward, and the load may increase. As a result, as shown in FIG. 7B, the 0 point position, which is the position of the pressing member 46 when the actual load Fref becomes smaller than the first threshold value ΔF, may shift (for example, Δx1 shift). ..

Further, even if the stroke control is started after the actual load Fref becomes smaller than the first threshold value ΔF, as shown in FIG. 8A, the decreasing gradient of the normal target load F *. When is large and the deviation is large, both the decreasing gradient of the actual load Fref and the changing gradient of the position or stroke of the pressing member 46 become large. Therefore, as shown in FIG. 8B, there is a problem that the variation at the 0 point position becomes large due to the variation at the time of detection. For example, the variation in the case shown in FIG. 8B is Δx2.

Therefore, in this embodiment, as shown in FIG. 4A, when the normal target load F * becomes 0, the actual load Fref is larger than the first threshold value ΔF, and the first threshold value is set. When it is smaller than the second threshold value ΔFq larger than ΔF, the load control is performed until the actual load Fref becomes smaller than the first threshold value ΔF, and then the stroke control is performed. To be done. As a result, noise can be made less likely to occur, and as shown in FIG. 4B, the 0-point position can be acquired when the load is controlled, and the 0-point position is highly reliable. Can be obtained.
The change pattern of the load or the like in this case is referred to as pattern 2.

On the other hand, as shown in FIG. 5A, when the actual load Fref when the normal target load F * becomes 0 is equal to or greater than the second threshold value ΔFq, the actual load is controlled in the load control. The decreasing gradient of Fref is suppressed. The second threshold value ΔFq can be set to a value at which, for example, when the target load F * at normal times is 0, the deviation becomes excessive and the decreasing gradient of the actual load Fref becomes large.
In this case, as shown in FIGS. 5A and 5C, the target load F0 * at the time of acquiring 0 points is set and set to a value in the vicinity of the actual load Fref, for example, based on the actual load Fref. The supply current to the electric motor 48 is acquired and supplied based on the deviation between the target load F0 * at the time of acquiring 0 points and the actual load Fref. That is, since the normal target load F * is 0, the deviation between the normal target load F * and the actual load Fref is large, and the decreasing gradient of the actual load Fref is large. On the other hand, since the target load F0 * at the time of acquiring 0 points has a magnitude close to the actual load Fref, the deviation is reduced and the decreasing gradient of the actual load Fref is reduced. After that, the target load F * at the time of acquiring 0 points is gradually reduced as the actual load Fref decreases, and the load control is continuously performed until the actual load Fref becomes smaller than the first threshold value ΔF. As a result, the rate of change of the position of the pressing member 46 can be suppressed, and the 0-point position, which is the position of the pressing member 46 when the actual load Fref becomes smaller than the first threshold value ΔF, can be accurately acquired. Can be done.
This change pattern such as load is referred to as pattern 3.

The 0-point position acquisition program represented by the flowchart shown in FIG. 6 is executed at predetermined set times when the normal target load F * decreases.
In S1, it is determined whether or not the normal time target load F * acquired and supplied by the brake ECU 112 is larger than 0, in other words, whether or not braking is ON. If the determination is YES, in S2, it is determined whether or not the actual load Fref is larger than the third threshold value ΔFp. The third threshold value ΔFp can be set to a size larger than the size that can be reached when the electric brake 8 is in the operating state, for example, a value larger than the first threshold value ΔF. If the determination in S2 is YES, the high load experience flag H is turned ON and the 0-point position acquisition completion flag S is turned OFF in S3. Then, in S4, load control is performed. The deviation between the actual load Fref and the normal target load F * is acquired, and the current based on the deviation is supplied to the electric motor 48. Further, the position Posx of the pressing member 46 is acquired based on the detected value of the rotation angle sensor 144. Hereinafter, S1 to 4 are repeatedly executed while the actual load Fref is larger than the third threshold value ΔFp.
The high load experience flag H is a flag that turns ON when the actual load Fref becomes larger than the magnitude ΔFp that can be considered that the electric brake 8 is in the operating state, and the 0 point position acquisition completion flag S is 0 point. This is a flag that turns ON when the position is acquired.

If the actual load Fref becomes equal to or less than the third threshold value ΔFp while the executions of S1 to S4 are repeated, the determination of S2 becomes NO. In S5, it is determined whether or not the actual load Fref is smaller than the first threshold value ΔF, the high load experience flag H is ON, and the 0 point position acquisition completion flag S is OFF. If the determination is NO, S4 is executed, and S1, 2, 5, and 4 are repeatedly executed. If the determination in S5 is YES, the position of the pressing member 46, that is, the position Posx of the pressing member 46 obtained by executing S4 is set to the 0 point position in S6, and the high load experience flag is set. H is OFF, and the 0-point position acquisition completion flag S is ON. After that, in S4, load control is performed, and the actual position Posx of the pressing member 46 is acquired based on the detected value of the rotation angle sensor 144.

On the other hand, when the normal target load F * becomes 0 and the determination of S1 becomes NO, S7 and subsequent steps are executed. The reason why the judgment of S1 is NO is that (i) if the judgment of S5 is not YES and the target load F * at normal time becomes 0, (ii) the judgment of S5 becomes YES, S6 is executed, and 0. After the point position is acquired, the normal target load F * may become 0.

In S7, it is determined whether or not S6 is executed, that is, whether or not the high load experience flag H is OFF and the 0 point position acquisition completion flag S is ON. If the determination is YES, stroke control is performed in S8. The actual stroke xpos from the 0 point position of the pressing member 46 determined in S6 is brought closer to the set target stroke xend. Then, in S9, the position Posx of the pressing member 46 this time is acquired based on the detected value of the rotation angle sensor 144. Hereinafter, S1, 7, 8 and 9 are repeatedly executed.

On the other hand, when the determination in S7 is NO, it is determined in S10 whether or not the actual load Fref is smaller than the first threshold value ΔF. If the determination is YES, the 0 point position is acquired in S11, stroke control is performed in S8 and 9, and the pressing member 46 is retracted by the set target stroke xend.

When the determination in S10 is NO, it is determined in S12 whether or not the actual load Fref is equal to or greater than the first threshold value ΔF and smaller than the second threshold value ΔFq. If the determination is YES, the load control is performed in S4. In this case, the normal target load F * is 0. If the determination in S10 is YES while S7, 10, 12, and 4 are repeatedly executed, the 0 point position is acquired in S11.

On the other hand, when the determination in S12 is NO, in S13 to 17, the target load F0 * at the time of acquiring 0 points is acquired, and the load based on the deviation between the target load F0 * at the time of acquiring 0 points and the actual load Fref. Control is done.
In this embodiment, the first set load F (1), the second set load F (2), the third set load F (3), ... (F (1) <F (2) <F (3) ) <...) Is predetermined and is close to the current actual load Fref, that is, the determination of S14 is YES, for example, the (k-1) set load F (k-1) is acquired. Then, the value obtained by subtracting the set value ΔFd from the third (k-1) set load F (k-1) is set as the target load F0 * at the time of acquiring 0 points.
F0 * = F (k-1) −ΔFd

Specifically, in S13, the parameter i is set to 1, and in S14, the actual load Fref is a magnitude between the first set load F (1) and the 0th set load (ΔF in this embodiment). It is determined whether or not it is. If the determination is NO, in S15, it is determined whether or not the parameter has reached the set value n. If the determination is NO, the parameter is incremented by 1 in S16, and in S14, the actual load Fref is the magnitude between the second set load F (2) and the first set load F (1). It is determined whether or not there is. Hereinafter, the set load is increased until the determination in S14 becomes YES. Then, when the determination in S14 is YES, in S17, the target load F * at the time of acquiring 0 points is a value smaller than the smaller (k-1) set load F (k-1) by the set value ΔFd. A current determined based on the deviation between the actual load Fref and the target load F0 * at the time of acquiring 0 points is supplied to the electric motor 48, and the load is controlled.

Hereinafter, by repeatedly executing S1,7,10,12 to 17,9, the load control based on the target load F0 * at the time of acquiring 0 points is continuously performed. If the actual load Fref becomes smaller than the first threshold value ΔF, the determination in S10 becomes YES, and the 0 point position is acquired in S11. After that, in S8, stroke control is performed, and the pressing member 46 is retracted by the set target stroke. Hereinafter, S1, 7, 8 and 9 are repeatedly executed.

For example, in the case of pattern 1, the determination of S5 becomes YES while the executions of S1, 2, 5, and 4 are repeated, and the 0 point position is acquired in S6, or the target load F * at normal time is set. When it becomes almost 0, the actual load Fref becomes smaller than the first threshold value ΔF, the determination of S10 becomes YES, and the 0 point position may be acquired in S11.

In the case of pattern 2, while S1,7,10,12,4 are repeatedly executed, the determination of S10 becomes YES, and the 0 point position is acquired in S11.
It should be noted that the execution of S12 is not indispensable, and even in the case of the pattern 2, S13 to 17 can be executed so that the decreasing gradient of the actual load Fref is suppressed.

In the case of pattern 3, by repeatedly executing S1,7,10,12, S13 to 17,9, the decreasing gradient of the actual load Fref is suppressed, and the position (stroke) change of the pressing member 46 is also gradual. Will be done. Then, the determination in S10 becomes YES, and the 0 point position is acquired in S11.

As described above, in this embodiment, the actual load Fref becomes smaller than the first threshold value ΔF, and after the 0 point is acquired, the load control is switched to the stroke control. As a result, it is possible to reduce the influence on the 0-point position caused by the defect that occurs when switching from the load control to the stroke control, and to acquire the highly reliable 0-point position.
Further, when the decreasing gradient of the normal target load F * is large, the actual load Fref when the normal target load F * becomes 0 is larger than the second threshold value ΔFq, and the deviation is large, the actual load Fref The decreasing gradient of is suppressed. As a result, it is possible to suppress the change in the position of the pressing member 46 when the actual load Fref becomes smaller than the first threshold value ΔF, and to obtain a highly reliable 0-point position.

As described above, in the present embodiment, at least one of the motor ECU 110 and the brake ECU 110, which stores S5, 6, 10, and 11 of the 0-point position acquisition program represented by the flowchart of FIG. 6, is executed. The 0-point position acquisition unit is composed of the parts and the like, and the current control unit is composed of the parts for storing S4, 13 to 17 and the parts for executing. The second current control unit is composed of a portion of the current control unit that stores S4, a portion that executes it, and the like, and a first current control unit is composed of a portion that stores S13 to 17 and a portion that executes S4.

The structure of the electric brake does not matter.
Further, in FIG. 5A, the set loads F (1), F (2), F (3), etc. are set at equal intervals, but it is not essential to set them at equal intervals. For example, the interval can be reduced as the actual load Fref approaches the first threshold value ΔF.
Further, the same applies to ΔFd, and it is not essential that the magnitudes are always the same, and the values can be determined based on the set load F (i-1) when the determination in S14 is YES.
Further, the present electric brake can be applied to both a manually driven vehicle and an automatically driven vehicle driven by the driver's operation. In addition, the present invention makes various changes and improvements based on the knowledge of those skilled in the art. It can be carried out in various forms.

8: Electric brake 32, 34: Friction pad 36: Pushing device 42: Electric actuator 46: Pressing member 48: Electric motor 110: Motor ECU 112: Brake ECU 146: Load sensor

Claimable invention

Hereinafter, patentable inventions will be described.
(1) A friction pad provided so as to face a brake rotating body that can rotate integrally with the wheels of the vehicle.
An electric brake control device that controls an electric brake including an electric actuator and a pressing member that includes a pressing member that can be moved by the electric actuator and presses the friction pad against the brake rotating body by controlling the electric actuator. And
A load sensor that detects the load applied to the pressing member, and
A 0-point position acquisition unit that sets the position of the pressing member as a 0-point position when the actual load, which is the detection value of the load sensor, becomes smaller than the first threshold value, which is the threshold value.
The actual load, which is the detection value of the load sensor, when the normal target load as the target load acquired based on at least one of the state of the vehicle and the state around the vehicle becomes equal to or less than the reference target load. The supply current to the electric actuator differs depending on whether it is larger than the second threshold value larger than the first threshold value or greater than or equal to the first threshold value and lower than or equal to the second threshold value. An electric brake control device including a current control unit for controlling.

When the decrease gradient of the normal target load is large, the change delay of the actual load with respect to the change of the normal target load becomes large, so that the actual load when the normal target load is the reference target load becomes large and the deviation is large. Become.

(2) When the actual load is larger than the second threshold value when the normal target load is equal to or less than the reference target load, the current control unit sets the target load based on the actual load. Item (1) includes a first current control unit that acquires the target load at the time of acquiring 0 points and controls the supply current to the electric actuator based on the deviation between the target load at the time of acquiring 0 points and the actual load. The electric brake control device described.

(3) In the current control unit, when the normal target load is equal to or less than the reference target load and the actual load is equal to or greater than the first threshold value and equal to or less than the second threshold value, the above The electric brake control device according to item (1) or (2), which includes a second current control unit that controls a supply current to the electric actuator based on a deviation between a normal target load and the actual load.

(4) The electric brake control device includes a stroke control unit that supplies a current corresponding to a deviation between an actual stroke of the pressing member and a predetermined set target stroke to the electric actuator.
The electric brake according to any one of items (1) to (3), wherein control by the stroke control unit is started after the zero point position of the pressing member is acquired by the zero point position acquisition unit. Control device.

(5) A friction pad provided so as to face a brake rotating body that can rotate integrally with the wheels of the vehicle.
An electric brake control device that controls an electric brake including an electric actuator and a pressing member that includes a pressing member that can be moved by the electric actuator and presses the friction pad against the brake rotating body by controlling the electric actuator. And
A load sensor that detects the load applied to the pressing member, and
A 0-point position acquisition unit that sets the position of the pressing member as a 0-point position when the actual load, which is the detection value of the load sensor, becomes smaller than the first threshold value, which is the threshold value.
The actual load, which is the detection value of the load sensor, when the normal target load as the target load acquired based on at least one of the state of the vehicle and the state around the vehicle becomes equal to or less than the reference target load. If it is larger than the second threshold value, which is larger than the first threshold value, it is based on the deviation between the target load at the time of acquiring 0 points as the target load acquired based on the actual load and the actual load. An electric brake control device including a current control unit that controls a supply current to the electric actuator.
The technical features described in any one of paragraphs (1) to (4) can be adopted in the electric brake control device described in this section. The current control unit corresponds to the first current control unit.

Claims (1)

A friction pad provided facing the brake rotating body that can rotate integrally with the wheels of the vehicle,
An electric brake control device that controls an electric brake including an electric actuator and a pressing member that includes a pressing member that can be moved by the electric actuator and presses the friction pad against the brake rotating body by controlling the electric actuator. And
A load sensor that detects the load applied to the pressing member, and
A 0-point position acquisition unit that sets the position of the pressing member as a 0-point position when the actual load, which is the detection value of the load sensor, becomes smaller than the first threshold value, which is the threshold value.
The actual load, which is the detection value of the load sensor, when the normal target load as the target load acquired based on at least one of the state of the vehicle and the state around the vehicle becomes equal to or less than the reference target load. The supply current to the electric actuator differs depending on whether it is larger than the second threshold value larger than the first threshold value or greater than or equal to the first threshold value and lower than or equal to the second threshold value. An electric brake control device including a current control unit for controlling.

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