JPH0522241U - Safety mechanism of vehicle brake control device and brake actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] By using a brake operating device with a backup system in addition to an electric brake actuator, it is possible to generate a braking force even when the braking force is lost due to an electrical failure. [Structure] When the ignition switch 9 is turned on, the coil 83 is energized, the relay switches 81 and 82 are switched, and the motor 51 can be controlled by the electronic control unit ECU. In this state, when the brake pedal 1 is depressed and the stroke sensor 2 detects the pedal stroke,
This signal is input to the electronic control unit ECU and the motor 51
Is actuated to actuate the brake actuator 50 so that the wheels can be braked in response to a signal from the pedal stroke sensor. When a failure such as disconnection occurs in the electric system, the relay switches 81 and 82 are switched to the illustrated state. When the brake pedal is depressed in this state, the generator 7 is driven, the motor 51 is driven, the brake actuator 50 is operated, and the wheel is braked.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a safety mechanism of a vehicle brake control device. More specifically, the present invention employs a backup system for an electric brake device (so-called by-wire brake device) and uses the above-mentioned electric brake device. In regard to the safety mechanism of the vehicle brake control device, the backup system will immediately activate the brake actuator even if an electrical failure occurs, so that the brakes can be reliably applied under any circumstances. Further, the present invention relates to a brake actuator suitable for the vehicle brake control device.

[0002]

[Prior Art]

 Generally, as a vehicle brake control device using a so-called by-wire type brake device that operates a brake by an electric signal, those described in JP-A-62-216852 and JP-A-2-267056 are known. There is. Each of these vehicle brake control devices detects the pedaling force or stroke of the brake pedal with a sensor, and controls the brake actuator with an electric control device according to the output from the sensor, which is provided on the wheel. It is designed to generate a predetermined brake pressure in the wheel cylinder.

[0003]

[Problems to be solved by the device]

 By the way, since the electric vehicle brake control device as described above can easily perform various controls by electric signals, it is particularly easy to adapt to an anti-skid brake system or a traction control system. Since its configuration is simpler than other mechanical systems, its usability may increase in the future. However, these vehicle brake control devices are designed to electrically control all the brake operating force based on a signal from a sensor that detects a pedaling force of a brake pedal or a stroke, that is, However, since it is an electric control mechanism that is different from the mechanical brake actuation mechanism that uses a conventional hydraulic or mechanical link, the brake will be activated if an electrical failure such as a sensor failure or wire breakage occurs. It stopped working and had a big safety problem. A brake actuator used in such an electric brake device is initially operated by a spool valve or the like as described in JP-A-62-216852 and JP-A-2-267056. Since another piston is operated to generate the brake pressure, there is a problem that the structure becomes complicated.

In view of the above, the present invention makes it possible to generate a braking force even when the braking force is lost due to an electrical failure, by using a brake actuation device using a backup system in addition to the above-mentioned electric brake actuator. In addition to solving the above-mentioned problems, a brake actuator having a simple structure suitable for use in the above-mentioned electric brake device is proposed.

[0005]

[Means for Solving the Problems]

 Therefore, the first technical solution of the present invention is a vehicle brake in which a brake actuator 50 is driven by a signal from an electronic control unit ECU to supply a predetermined hydraulic pressure to a wheel cylinder provided on a wheel. A safety mechanism of a control device, wherein the brake actuator 50 includes a motor 51 driven by a signal from an electronic control unit ECU, a screw member 58 rotated by the drive of the motor 51, and a cylinder by rotation of the screw member 58. And a piston 60 configured to generate hydraulic pressure in the hydraulic pressure generating chamber 61, and the motor 51 is connected to a generator 7 that generates power by operating a brake pedal via a switch 82. Therefore, the switch 82 is turned on only when the circuit of the vehicle brake control device fails. According to the second technical solution, the motor 51 can be driven by the output of the generator 7 which is operated by operating the brake pedal 1. The third technical solution is that the electromagnetic clutch mechanism 52 is connected to the screw member only when an abnormality occurs in the electric system of the vehicle brake control device. The fourth technical solution is that the brake actuator 50 is a motor 51 and a screw member that is rotated by the drive of the motor 51. 58 and a piston configured to generate hydraulic pressure in the hydraulic pressure generating chamber 61 by moving in the cylinder by the rotation of the screw member 58. A ton 60, and an electromagnetic clutch mechanism 52 is arranged opposite to the screw member 58. The electromagnetic clutch mechanism 52 is arranged in one direction of the screw member when connected to the screw member. It is characterized in that it is allowed to rotate only, and these are the means for solving the problems.

[0006]

[Action]

 [Normal] When the motor 51 is driven by a signal from the electronic control unit ECU, the piston 60 resists the urging force of the spring 66 by the operation of the pinion 53, the gear 54, the screw 58, and the nut 59. It moves to the left and generates a predetermined hydraulic pressure in the hydraulic pressure generation chamber 61. The hydraulic pressure generated in the hydraulic pressure generation chamber 61 is supplied to the wheel cylinders mounted on the wheels to brake the wheels. When the driving force from the motor 51 disappears, the piston 60 returns to the initial state by the urging force of the spring 66.

[Abnormality] In the unlikely event that the electric brake device is disconnected or battery abnormality occurs, the relay switches 81 and 82 are switched to stop the energization of the electromagnetic clutch 52 and the spring 55 urges the electromagnetic force. The clutch 52 is pressed by the gear 54, and the rotation of the screw member in the direction in which the brake is loosened is prohibited. In this state, when the brake pedal shown in FIG. 1 is operated, the motor 51 is driven by the output from the generator 7, the piston 60 is operated via the screw 58, and the brake pressure is generated in the hydraulic pressure generation chamber 61. can do.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to a first embodiment of the present invention. In FIG. 1, 1 is a brake pedal, 2 is a stroke sensor of the brake pedal 1, 3 is a rack pivotally attached to the brake pedal, 4 is a pinion meshing with the rack, 5 is a gear 6 fixed coaxially with the pinion 4, Pinions 7 and 7 meshing with the gear 5 are generators capable of generating electricity by rotating the pinion 6. The stroke sensor 2 is connected to an electronic control unit ECU, and the electronic control unit ECU is connected to an electromagnetic clutch 52 and a motor 51 of a brake actuator 50 having a structure described later via relay switches 81 and 82 as shown in the figure. Is connected. The relay switches 81 and 82 have a mechanism that switches when the coil 83 is energized, and the coil 83 is connected to the battery 10 via the ignition switch 9. For this reason, when the coil 83 is energized, the relay switch 81 is turned on from the state shown in the figure to bring the electronic control unit ECU and the electromagnetic clutch 52 into conduction, and the relay switch 82 is also switched to the B position so that the motor 51 is connected. The electronic control unit ECU is electrically connected. Further, the relay switch 82 is in the A position when the coil 83 is not energized and is connected to the generator 7.

In the above configuration, when the ignition switch 9 is turned on, the coil 83 is energized, the relay switches 81 and 82 are switched from the illustrated state, and the electronic control unit ECU makes the motor 51 controllable. At this time, the electromagnetic clutch 52 is also energized, so that the connection between the electromagnetic clutch 52 and the screw member is released as described later. In this state, when the brake pedal 1 is stepped on and the stroke sensor 2 detects the pedal stroke, this signal is input to the electronic control unit ECU, which drives the motor 51 to operate the brake actuator 50, and the pedal stroke. The wheels can be braked in response to the signal from the sensor.

In the above state, if a failure such as disconnection occurs in the electric system, the coil 83 is de-energized and the relay switches 81 and 82 are in the illustrated state (the relay switch 81 is off, the relay switch 82 is off. Switch to A contact). At the same time, the energization of the electromagnetic clutch 52 is stopped, the electromagnetic clutch 52 is connected to the screw member, and the rotation direction of the screw member in the brake releasing direction is restricted. When the brake pedal is depressed in this state, the movement of the brake pedal 1 causes the rack 3 to move leftward in the figure, which causes the pinion 4 to rotate. The rotation of the pinion 4 also rotates the gear 5 that is coaxially fixed, and the pinion 6 that meshes with the gear 5 also rotates to drive the generator 7. The electric current generated by driving the generator flows to the motor 51 via the relay switch 82 to drive the motor 51, and the driving of the motor 51 activates the brake actuator 50 to brake the wheels. it can.

As described above, in the present invention, the backup system is adopted in the electric braking device (so-called by-wire braking device), and even if an electrical failure occurs in the by-wire braking device. Since the brake activation device by the backup system is activated immediately, the braking force can be reliably generated even when the braking force is lost due to an electrical failure, and an extremely safe vehicle brake control device is obtained. be able to.

Next, a detailed description of the brake actuator 50 according to the present invention will be given with reference to FIG. As shown in FIG. 2, the brake actuator 50 includes a motor 51, a pinion 53 rotated by the motor 51, a gear 54 meshing with the pinion 53, and a screw as a screw member fixed to the gear 54. 58, a nut 59 screwed to the screw 58, a piston 60 fixed to the nut 59, a hydraulic pressure generating chamber 61 that generates hydraulic pressure by the movement of the piston 60, a reservoir 62 and these members efficiently. And a housing 63 that can be stored in. The piston 60 is slidably fitted in a cylinder formed in the housing 63, and the nut 59 screwed to the screw 58 is fixed to the piston 60 as described above. The nut 59 has a groove 64 coaxially with the axis of the screw, and a rotation stop 65 is fitted in the groove 64 so that the nut 59 does not rotate even if the screw 58 rotates. .. The piston 60 is normally urged rightward in the figure by a spring 66. When the screw 58 rotates, the nut 59 moves in the cylinder and the piston 60 slides in the cylinder.

In the brake actuator 50, when the motor 51 is driven by a signal from the electronic control unit ECU, the pinion 53 and the gear 54 rotate, and the screw 58 rotates accordingly. The rotation of the screw 58 is transmitted to the nut 59, and the nut 59 moves on the screw 58 in the figure to the left in the figure while the rotation is restricted by the rotation stop 65. By the movement of the nut 59, the piston 60 integrated with the nut 59 also moves to the left in the drawing against the biasing force of the spring 66, and a predetermined hydraulic pressure is generated in the hydraulic pressure generation chamber 61. The oil pressure generated in the oil pressure generating chamber 61 is supplied to the wheel cylinders mounted on the wheels to brake the wheels. When the driving force from the motor 51 disappears, the piston 60 returns to the initial state by the urging force of the spring 66. As described above, this brake actuator adopts the master cylinder type, and when the motor is driven electrically, the wheels can be braked.

By the way, the brake actuator 50 employs a mechanism in which a brake actuation device by a backup system works immediately even if an electrical failure occurs in an electric brake device. The configuration will be described. As shown in FIG. 2, an electromagnetic clutch 52 is arranged so as to face the gear 54 of the brake actuator, and the electromagnetic clutch 52 is integrally provided with a shaft 67. The shaft 67 is rotatably supported by an electromagnetic clutch support member 68, and is further supported so as to be movable in the axial direction (left and right in the drawing). A known clutch spring 56 is provided between the shaft 67 and the electromagnetic clutch support member 68. The clutch spring 56 is formed in a coil shape, and a shaft 67 is inserted into the center of the clutch spring 56. When the shaft 67 rotates in the direction in which the coil is closed, the rotation of the shaft 67 is prohibited by the action of the coil, and the coil is When the shaft 67 rotates in the loosening direction, the shaft 67 is allowed to rotate. Further, a flange 69 is formed on the shaft 67, an electromagnet 57 penetrating the shaft 67 is attached to the flange 69, and an electromagnetic clutch is provided between the electromagnet 57 and the electromagnetic clutch 52. A spring 55 for urging 52 toward the gear 54 is arranged.

Therefore, when electricity is flowing through the electromagnet 57 (normal), the electromagnetic clutch 52 moves to the right in the figure against the biasing force of the spring 55 due to the attraction of the electromagnet 57. The electromagnetic clutch 52 and the gear 54 are disconnected from each other, and the gear 54 can be freely rotated by the rotational force of the motor 5. Further, when electricity stops flowing to the electromagnet 57 (at the time of abnormality), the attraction force of the electromagnet 57 disappears and the electromagnetic clutch 52 moves to the left in the figure by the urging force of the spring 55, and the electromagnetic clutch 52 and the gear 54 Are connected. In this state, due to the action of the clutch spring 56, the gear 54 can rotate only in one direction (only in the brake pressing direction), and the loosening of the brake is prevented.

Next, the operation of the brake actuator 50 will be described. [Normal] When the motor 51 is driven by a signal from the electronic control unit ECU, the piston 60 resists the biasing force of the spring 66 by the operation of the gear, the screw 58, and the nut 59 as described above. It moves to the left and generates a predetermined hydraulic pressure in the hydraulic pressure generation chamber 61. The hydraulic pressure generated in the hydraulic pressure generation chamber 61 is supplied to the wheel cylinders mounted on the wheels to brake the wheels. When the driving force from the motor 51 disappears, the piston 60 returns to the initial state by the urging force of the spring 66. As described above, the brake actuator 50 can generate a braking force by the operation of the motor 50 driven by the signal from the electronic control unit ECU.

[Abnormality] In the event that a wire breakage or a battery abnormality occurs in the electric brake device, the relay switches 81 and 82 are switched to stop the energization of the electromagnet 57, and the spring 55 is attached. The electromagnetic clutch 52 is pressed against the gear 54 by the force. When the brake pedal shown in FIG. 1 is operated in this state, the motor 51 is driven by the output from the generator 7, and the piston 60 is operated via the screw 58 to generate a brake pressure in the hydraulic pressure generation chamber 61. be able to. In this state, the piston 60 may move to the right in the figure due to the brake pressure. However, since the clutch spring 56 prevents the reverse rotation of the electromagnetic clutch, such a state can be avoided. That is, the motor 51 can rotate only in the pressurizing direction.

As described above, in the safety mechanism of the brake control device for a vehicle of the present invention, when an electric failure such as a sensor failure or a wire breakage occurs once while the brake control is normally performed by the electric method. Since the brake can be immediately actuated by the backup system, it is possible to provide an extremely safe vehicle braking control device. Further, the brake actuator of the present invention can drive a motor to move a piston arranged in a cylinder to generate a predetermined hydraulic pressure in the hydraulic pressure generating chamber 28 by a signal from an electronic control unit ECU. Therefore, it is possible to obtain a brake actuator having a simple structure. Also, the electromagnetic clutch can be used to reliably stop the reverse movement of the piston.

The mechanism of the brake accumulator 6 is not limited to the one described above. For example, a mechanism for operating a piston using a linear motor or an electrostrictive element described in Japanese Patent Laid-Open No. 62-216852 is used. Various mechanisms such as a mechanism for activating a piston can be adopted. Further, the mechanical brake system may be adopted not only on the front wheel side as in the above-described embodiment but also on all wheels or only the rear wheel side.

[0020]

[Effect of the device]

 As described in detail above, according to the present invention, even if the brake actuator cannot be operated due to an electrical failure in the electric vehicle braking control device, the electromagnetic clutch immediately operates and the backup system operates at the same time. Then, the brake can be operated by a separate system, a very safe safety mechanism for the vehicle brake control device can be obtained, and a brake actuator with a simple structure can be obtained. And so on.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a safety mechanism of a vehicle brake control device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a brake actuator used in the present invention.

[Explanation of symbols]

 1 Brake Pedal 2 Stroke Sensor 7 Generator 9 Ignition Switch 10 Battery 50 Brake Actuator 51 Motor 52 Electromagnetic Clutch 81, 82 Relay Switch

Claims (4)

[Scope of utility model registration request] 1. A safety mechanism of a vehicle brake control device, wherein a brake actuator 50 is driven by a signal from an electronic control unit ECU so that a predetermined hydraulic pressure can be supplied to a wheel cylinder provided on a wheel. The actuator 50 is driven by a signal from an electronic control unit ECU, a motor 51, a screw member 58 that is rotated by the drive of the motor 51, and a rotation of the screw member 58 moves in the cylinder to apply hydraulic pressure to the hydraulic pressure generation chamber 61. And a piston 60 that is configured to generate, and the motor 51 is connected via a switch 82 to a generator 7 that generates power by operating a brake pedal, the switch 82 being the vehicle brake control device. It turns on only when the circuit of the A safety mechanism for a vehicle brake control device, characterized in that the motor 51 can be driven by the output of the generator 7 that operates in this way. 2. The brake pedal 1 is connected to the generator 7 via a gear, and the generator 7 can be driven by the reciprocal movement of the brake pedal 1. A safety mechanism of the vehicle brake control device described. 3. An electromagnetic clutch mechanism 52 is arranged so as to face the screw member 58, and the electromagnetic clutch mechanism 52 is connected to the screw member only when an abnormality occurs in the electric system of the vehicle brake control device. The safety mechanism of the vehicle brake control device according to claim 1 or 2, wherein the screw member is configured to allow rotation in only one direction. 4. The brake actuator 50 is a motor 5
1, a screw member 58 that is rotated by the drive of the motor 51, and a piston 60 that is configured to move in the cylinder by the rotation of the screw member 58 and generate a hydraulic pressure in the hydraulic pressure generation chamber 61. An electromagnetic clutch mechanism 52 is disposed so as to face the screw member 58, and the electromagnetic clutch mechanism 52 is configured to allow only one-direction rotation of the screw member when connected to the screw member. A brake actuator for a vehicle brake control device.