JP2008132906A - Electric disk brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric disk brake device capable of suppressing fluctuation of the wall thickness of a disk and suppressing occurrence of a judder by removing rust in an early stage. <P>SOLUTION: The electric disk brake device comprises an electric-driven caliper 10 housing thrust mechanisms 13, 40 for pressing brake pads 14, 15 against a disk 11 rotated together with a wheel, and an electric motor 19 for driving the thrust mechanisms 13, 40, and a control means for controlling the electric motor 19 based on the operation of a brake pedal. The control means performs the rust removing control for removing the rust by bringing the brake pads 14, 15 into contact with the disk 11 by the electric motor 19 via the thrust mechanisms 13, 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric disk brake device used for braking a vehicle.

In an electric vehicle that travels by driving a traction motor with the charging power of a battery or the generated power of a fuel cell, it has been studied to adopt an electric disc brake device that similarly brakes wheels with electric power. As such an electric disc brake device, there is one having an electric caliper that includes a thrust mechanism that presses a brake pad against a disc that rotates with a wheel and an electric motor that drives the thrust mechanism (see, for example, Patent Document 1). ).
JP 2004-124950 A

  By the way, in the disc brake, when the non-use state continues, the disc may be rusted, and such rust is usually removed by contact of the brake pad during braking. However, if the rust proceeds without removing the rust, the progress is not constant depending on the location, and there is a high possibility that the disc will have a thickness variation after the rust is removed by contact with the brake pad. Become. Such a wall thickness variation is not preferable because it causes judder generation. And since the electric disc brake device as described above generates a braking force so as to compensate for the regenerative braking of the traction motor, it may not be used even during traveling, and the non-use state may continue for a long time. Increases nature.

  Therefore, an object of the present invention is to provide an electric disk brake device that can suppress the fluctuation of the thickness generated in the disk by removing rust at an early stage and can suppress the occurrence of judder.

  In order to achieve the above object, an invention according to claim 1 is directed to an electric caliper that includes a thrust mechanism that presses a brake pad against a disk that rotates with a wheel, and an electric motor that drives the thrust mechanism, and the electric motor. An electric disc brake device having control means for controlling based on operation of a brake pedal, wherein the control means is operated by the electric motor via the thrust mechanism regardless of operation of the brake pedal during rotation of the wheel. The brake pad is brought into contact with the disc to perform rust removal control for removing rust.

  The invention according to claim 2 is the invention according to claim 2, wherein the control means has rust generation amount estimation means for estimating the amount of rust generated on the disk, and is estimated by the rust generation amount estimation means. The time for which the brake pad is brought into contact with the disk in the rust removal control is changed according to the amount of generated rust.

  According to the first aspect of the present invention, the control means performs rust removal control for removing rust by bringing the brake pad into contact with the disc through the thrust mechanism by the electric motor regardless of the operation of the brake pedal during rotation of the wheel. Therefore, the rust of the disk can be removed early. Therefore, it is possible to suppress the thickness variation that occurs in the disk and to suppress the occurrence of judder.

  According to the invention of claim 2, the control means changes the time for contacting the brake pad to the disc in the rust removal control according to the amount of rust estimated by the rust generation amount estimation means. Accuracy can be improved.

  An electric disc brake device according to an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the electric disk brake device of the present embodiment includes a disk 11 that is provided on each wheel (not shown) of the vehicle and rotates integrally with the wheel, and an electric caliper 10 that brakes each disk 11 with friction. And have.

  As shown in FIG. 2, each electric caliper 10 has a caliper body 12 disposed on one side in the axial direction of the disk 11. The caliper body 12 is formed in a substantially C shape and straddles the disk 11. A claw portion (thrust mechanism) 13 extending to the opposite side is integrally coupled. Brake pads 14 and 15 are provided on both sides of the disk 11 in the axial direction. The brake pads 14 and 15 are supported by a carrier 16 fixed on the vehicle body side so as to be movable along the axial direction of the disk 11, and transmit braking torque to the carrier 16. Is guided to be slidable along the axial direction of the disk 11 by a slide pin (not shown) attached to the carrier 16.

  A caliper case 18 is coupled to the caliper body 12, and an electric motor 19 and a position detector 20 are provided in the case 18. On the other hand, a ball ramp mechanism 21 and a speed reduction mechanism 22 are provided inside the caliper body 12. A cover 23 is attached to the rear end of the case 18.

  The electric motor 19 includes a stator 25 fixed to the inner periphery of the case 18, and a rotor 28 inserted into the stator 25 and rotatably supported by the case 18 by bearings 26 and 27. The position detector 20 includes a resolver stator 29 fixed to the case 18 side and a resolver rotor 30 attached to the rotor 28. Based on these relative rotations, the rotational position of the rotor 28, that is, the motor rotational position of the electric motor 19 is determined. It is to detect.

  The ball ramp mechanism 21 includes an annular first disk 32 and second disk 33, and a plurality of balls (steel balls) 34 interposed therebetween. The first disk 32 is rotatably supported by the caliper body 12 by a bearing 35, and a cylindrical portion 36 that is inserted into the rotor 28 is integrally formed. A cylindrical sleeve 37 having a smaller diameter than the cylindrical portion 36 is integrally formed on the second disk 33, and the sleeve 37 is inserted into the cylindrical portion 36.

  For example, three ball grooves 38 and 39 each having an arc shape extending along the circumferential direction are formed on the opposing surfaces of the first disk 32 and the second disk 33 of the ball ramp mechanism 21. These ball grooves 38 and 39 are extended in the range of an equal central angle (for example, 90 °) and inclined in the same direction. Then, a ball 34 is inserted between the ball grooves 38 and 39 formed in the first disk 32 and the second disk 33, and the ball grooves 38 and 39 are moved by the relative rotation of the first disk 32 and the second disk 33. As the ball 34 rolls, the first disk 32 and the second disk 33 are relatively displaced in the axial direction. At this time, when the first disk 32 rotates counterclockwise with respect to the second disk 33, they are displaced in the direction of separating.

  A piston (thrust mechanism) 40 is provided between the second disk 33 and the brake pad 14. The piston 40 has a cylindrical member 42a in which a screw portion 41 is formed on the outer periphery. The cylindrical member 42a is inserted into the sleeve 37 of the second disk 33 and is screwed into a screw portion 43 formed on the inner periphery thereof. The cylindrical member 42a is fitted with a two-side chamfered portion (not shown) of a shaft 45 attached to the case 18 via a bracket 44, and its rotation is restricted. Further, the piston 40 has a substantially disk-shaped pressing member 42b that is connected to the shaft 45 of the cylindrical member 42a in a state in which the rotation is restricted on the opposite side. And between the cylindrical member 42a and the press member 42b, the thrust sensor (thrust detection means) 46 which detects the piston thrust which the piston 40 receives is provided.

  The screw portion 41 of the cylindrical member 42 of the piston 40 and the screw portion 43 of the sleeve 37 of the second disk 33 form an irreversible screw, and the piston 40 moves even if a force acts in the axial direction. However, the second disk 33 is moved to the disk 11 side by rotating counterclockwise.

  An elastic member 49 is interposed between spring receivers 47 and 48 formed on the outer peripheral portion of the shaft 45 and the inner peripheral portion of the sleeve 37 of the second disc 33, respectively, and the second disc 33 causes the ball 34 to be It is urged to be sandwiched between one disk 32. The shaft 45 is attached to the bracket 44 by an adjustment screw 50 and a lock nut 51.

  A cylindrical spring holder 67 is attached to the outer periphery of the tip of the sleeve 37 of the second disk 33. One end portion of the spring holder 67 engages with the tip end portion of the cylindrical portion 36 of the first disk 32 to limit the relative rotation thereof to a certain range. A coil spring 69 is wound around the spring holder 67, and the coil spring 69 is twisted with a predetermined set load, one end of which is coupled to the spring holder 67, and the other end of the first disk 32. It is coupled to the cylindrical portion 36 (the coupling portion is not shown).

  Next, the basic operation of the electric caliper 10 having the above configuration will be described.

  In the non-braking state, the ball 34 of the ball ramp mechanism 21 is at the deepest end of the ball grooves 38 and 39, and the first disk 32 and the second disk 33 are closest. When generating the braking force, the controller 100 rotates the rotor 28 of the electric motor 19 clockwise. Then, the rotational torque of the roller 28 is amplified by the speed reduction mechanism 22 and transmitted to the first disk 32.

  The rotational force of the first disk 32 is transmitted to the second disk 33 via the coil spring 69. Before the piston 40 presses the brake pads 14 and 15, almost no axial load acts on the piston 40, and the resistance generated in the screw portions 41 and 43 between the piston 40 and the second disk 33 is small. The set load of the coil spring 69 causes the second disk 33 to rotate integrally with the first disk 32, causing relative rotation between the second disk 33 and the piston 40, and the piston 40 is moved by the action of the screw portions 41 and 43. Advance to the disk 11 side. Thereby, the screw portions 41 and 43 constitute a conversion mechanism portion that converts the rotational motion of the electric motor 19 into the linear motion of the piston 40.

  Then, the piston 40 comes into contact with one brake pad 14 and presses it against the disk 11. The reaction force causes the caliper body 12 to move along the slide pin of the carrier 16, so that the claw portion 13 moves to the other brake pad. 15 is pressed against the disk 11.

  After both brake pads 14 and 15 are pressed against the disk 11, a large axial load acts on the piston 40 due to the reaction force, so that the resistance of the screw portions 41 and 43 increases and the set load of the coil spring 69 is increased. As a result, the second disk 33 stops rotating, and as a result, the coil spring 69 is bent and relative rotation occurs between the first disk 32 and the second disk 33 of the ball ramp mechanism 21. As a result, the ball 34 rolls in the ball grooves 38 and 39 to advance the second disk 33 and the piston 40 together (that is, linear movement), and the brake pads 14 and 15 are further pressed against the disk 11 by the piston 40. . Thereby, the ball ramp mechanism 21 also constitutes a conversion mechanism unit that converts the rotational motion of the electric motor 19 into the linear motion of the piston 40.

  The electric motor 19, the position detector 20, and the thrust sensor 46 are communicably connected to a motor ECU 100 shown in FIG. 1 that is integrally provided opposite to the claw portion 13 of the caliper body 12.

  The motor ECU 100 of each electric caliper 10 is communicably connected to a common main ECU (control means, rust generation amount estimation means) 101 via a CAN which is an in-vehicle communication network. A motor driver 103 that can be energized from the battery 102 is connected to the ECU 100. Then, the motor ECU 100 controls the electric motor 19 based on the detection results of the position detector 20 and the thrust sensor 46 according to a command from the main ECU 101.

  The main ECU 101 includes a stroke simulator 106 that generates an operation reaction force to the brake pedal 105 that is operated by the driver and detects the operation amount of the brake pedal 105, a wheel speed sensor 107 that detects the speed of each wheel, a vehicle The GPS 108 for detecting the position information of the vehicle, the temperature sensor 109 for detecting the temperature, and the humidity sensor 110 for detecting the humidity are connected.

  The main ECU 101 calculates the piston thrust generated by each electric caliper 10 from the detection result of the stroke simulator 106, that is, the operation amount of the brake pedal 105, the detection result of the wheel speed sensor 107, etc., and the motor of each electric caliper 10 Each of the motor ECUs 100 transmits the detection result of the position detector 20, that is, the actual piston position corresponding to the rotational position of the electric motor 19, the current value of the electric motor 19, and the detection result of the thrust sensor 46, that is, the actual By controlling the electric motor 19 based on the piston thrust, control is performed so that the piston thrust becomes the target thrust.

  Further, the main ECU 101 stores temperature data detected by the temperature sensor 109 and humidity data detected by the humidity sensor 110 in order to perform rust removal control described later.

  Next, the control content of rust removal control will be described with reference to the flowchart of FIG. The control shown in this flowchart is a process that is executed every time the ignition switch of the vehicle is turned on.

  The main ECU 101 determines the start of the vehicle after the ignition switch is turned on from the output of the wheel speed sensor 107 (step S1), and when the start of the vehicle is detected, it is the time when the last braking stored is performed. The braking time is read, the non-braking time is calculated from the braking time and the current time, and the temperature and humidity measured by the temperature sensor 109 and the humidity sensor 110 during the non-braking time are read (step S2).

  Next, the main ECU 101 determines whether or not rust is likely to occur (step S3). If it is determined that rust is likely to occur in step S3, the main ECU 101 estimates the amount of rust generated (step S4).

  At this time, since the occurrence of rust depends not only on the non-braking time but also on the environment as well as the non-braking time, the rust is determined in step S3 from the relationship between the temperature and humidity during the non-braking time read out in step S2. Calculate the estimated rust occurrence time that is predicted to occur, and if the non-braking time has passed this estimated rust occurrence time, it is determined that there is a possibility of rust occurrence, while the non-braking time exceeds the estimated rust occurrence time. If not, it is determined that there is no possibility of rusting. Here, as shown in FIG. 4, the rust generation rate tends to be high at the beginning of the non-braking time and then decrease, and the higher the air temperature with such a tendency (temperature A <temperature B <temperature C). , Rust generation rate tends to increase. Further, as shown in FIG. 5, the amount of rust generated naturally increases with the elapse of the non-braking time, but as the temperature increases with such a tendency (temperature A <temperature B <temperature C). ), Rust generation tends to increase. Further, humidity has similar characteristics. For this reason, the main ECU has a map of the relationship between the non-braking time and the amount of rust generated due to temperature differences and humidity differences, and in step S4, the non-braking time, temperature data (for example, average value), humidity data ( For example, the rust generation amount is estimated from the average value). Moreover, the estimation accuracy of the occurrence of rust can be improved by adding position information such as whether or not it is near the sea from the position information of the GPS 108 to the map information of the navigation system as a condition.

  And main ECU101 changes the rust removal time (time which removes rust by rust removal control) which makes brake pads 14 and 15 contact disk 11 in rust removal control according to the amount of rust generated in Step S4. (Step S5). That is, when it is predicted that the amount of rust generated is large, the rust removal time is set long, and when it is predicted that the amount of rust generation is small, the rust removal time is set short.

  Next, the main ECU 101 performs a rust removal operation for bringing the brake pads 14 and 15 into contact with the disc 11 for the rust removal time set in step S5 regardless of the operation of the brake pedal 105 detected by the stroke simulator 106. The electric motor 19 is controlled (step S6). During this rust removal operation, the brake pads 14 and 15 are pressed against the disc 11 with a pressing force that does not substantially generate braking force on the vehicle. At this time, the pressing force is changed according to the traveling speed of the vehicle. That is, the pressing force is weakened during traveling in the low speed region, and the pressing force is increased during traveling in the high speed region. When the brake pedal 105 is operated and normal braking is performed during the rust removal control, the remaining rust removal time is set according to the amount of rust estimated to be removed by the normal braking. Shorten.

  Then, the main ECU 101 determines whether or not the rust removal operation for all the wheels has been completed (step S7). If it is determined that the rust removal operation has been completed, the main ECU 101 ends the rust removal control.

  According to the electric disc brake device of the present embodiment described above, the main ECU 101 causes the brake pads 14 and 15 to contact the disc 11 by the electric motor 19 regardless of the operation of the brake pedal 105 during the rotation of the wheels, and rusts. Since the rust removal control is performed to remove the rust, the rust of the disk 11 can be removed early. Therefore, the thickness fluctuation generated in the disk 11 can be suppressed, and the occurrence of judder can be suppressed.

  Also, the main ECU 101 estimates the amount of rust generated from time, temperature and humidity, and changes the rust removal time for contacting the brake pads 14 and 15 with the disk 11 in the rust removal control according to the estimated amount of rust generated. Therefore, the accuracy of rust removal control can be improved.

1 is an overall configuration diagram showing an electric disk brake device according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the block diagram which made the cross section the electric caliper which shows the electric disc brake device of one Embodiment of this invention, and a disc. It is a flowchart which shows the control content of the rust removal control in the electric disc brake device of one Embodiment of this invention. It is a characteristic diagram which shows the relationship between the non-braking time and the rust generating speed of a disk. It is a characteristic diagram which shows the relationship between the non-braking time and the amount of rust generation of a disk.

Explanation of symbols

10 Electric caliper 11 Disc 13 Claw (thrust mechanism)
14, 15 Brake pads 19 Electric motor 40 Piston (thrust mechanism)
101 Main ECU (control means, rust generation amount estimation means)
105 Brake pedal

Claims (2)

An electric disc having an electric caliper that includes a thrust mechanism that presses a brake pad against a disc that rotates with a wheel, an electric motor that drives the thrust mechanism, and a control unit that controls the electric motor based on an operation of a brake pedal Brake device,
The control means performs rust removal control for removing rust by bringing the brake pad into contact with the disc through the thrust mechanism by the electric motor regardless of operation of the brake pedal during rotation of the wheel. Electric disc brake device.   The control means has rust generation amount estimation means for estimating the amount of rust generated on the disk, and the disk in the rust removal control according to the amount of rust estimated by the rust generation amount estimation means 2. The electric disk brake device according to claim 1, wherein a time for contacting the brake pad is changed.

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