Integrated self-locking braking system and method

Abstract

An integrated self-locking brake system and method, the system includes a motor assembly, a main housing, a transmission mechanism, a master cylinder, and a fluid storage pot; the motor assembly includes a motor and a motor control unit, and the motor control unit is integrated at the rear of the motor; the transmission mechanism includes a worm, a worm wheel, a worm wheel shaft, and a master cylinder push rod, wherein the worm and the worm wheel mesh to form a worm wheel transmission pair, the worm wheel shaft and the master cylinder push rod and the ball constitute a ball screw transmission pair, and the worm wheel is fixedly matched with the worm wheel shaft; the master cylinder is fixedly connected to the main housing by bolts, and a master cylinder piston is matched in the master cylinder, the master cylinder piston is slidably matched with the master cylinder body and is sealed with a sealing ring, the interior of the master cylinder piston is a master cylinder high-pressure chamber, and the exterior of the master cylinder piston is in contact with the master cylinder push rod; the output torque of the motor pushes the master cylinder piston through the worm wheel transmission pair and the ball screw transmission pair, so that it can be telescopically moved in the master cylinder to generate and release braking pressure.

Description

Technical Field

[0001] The present invention relates to a braking system and a method thereof, and in particular to an integrated self-locking braking system and a method thereof, and belongs to the technical field of autonomous driving vehicle manufacturing. Background Art

[0002] At present, the research on autonomous driving technology mainly focuses on vehicle control technology, environmental perception technology and path planning technology. There is still little research on vehicle steering control, braking control and throttle control, especially vehicle braking system.

[0003] The hydraulic brake system of traditional cars is applied by the driver by stepping on the brake pedal. With the development of autonomous driving technology, autonomous vehicles require the braking system to actively brake the vehicle without driver operation. Currently, the braking devices that can achieve active braking are mostly electric power assist or ESC (Electronic Stability Controller. Electronic stability control system of the vehicle body), while retaining control devices such as brake pedals, and are mostly used in autonomous passenger cars. When the above two types of braking devices are used in related fields such as autonomous logistics vehicles, they have complex structures, large volumes, high control difficulties, and high costs.

[0004] In addition, autonomous logistics vehicles also need parking brakes in addition to driving brakes. Traditional vehicles are mostly equipped with two systems: driving brakes and parking brakes. For autonomous logistics vehicles, it is more complicated to coordinate the control of the two systems: driving brakes and parking brakes.

[0005] As in the prior art, CN105523028A discloses an electro-hydraulic composite brake system with an electric brake booster function. When the brake pedal is pressed, the push rod pushes the rack and the brake master cylinder piston. At the same time, according to the signal of the displacement sensor at the pedal, the electronic control unit controls the motor to output torque, and through the two sets of transmission pairs of the worm gear pair and the rack and pinion pair, the master cylinder piston is assisted to output the brake pressure to the wheel cylinder. However, the brake pedal in the prior art occupies space and increases the manufacturing cost.

[0006] Therefore, designing a braking device with a simple structure, low cost and capable of simultaneously meeting the driving braking and parking braking requirements of an autonomous driving vehicle is an urgent problem to be solved. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a wire-controlled self-locking brake master cylinder system with a simple structure, low cost and capable of simultaneously meeting the driving brake and parking brake of an autonomous logistics vehicle. The technical solution is as follows:

[0008] An integrated self-locking brake system includes a motor assembly, a main housing, a transmission mechanism, a master cylinder, and a fluid storage pot, and is characterized in that: the motor assembly includes a motor and a motor control unit, and the motor control unit is integrated at the rear of the motor; the transmission mechanism includes a worm, a worm wheel, a worm wheel shaft, and a master cylinder push rod, wherein the worm and the worm wheel are meshed to form a worm wheel transmission pair, the worm wheel shaft and the master cylinder push rod and the balls constitute a ball screw transmission pair, and the worm wheel is fixedly matched with the worm wheel shaft; the master cylinder is fixedly connected to the main housing by bolts, and a master cylinder piston is matched in the master cylinder, the master cylinder piston is slidably matched with the master cylinder body, and is sealed with a sealing ring, the interior of the master cylinder piston is a master cylinder high-pressure chamber, and the exterior of the master cylinder piston is in contact with the master cylinder push rod; the output torque of the motor pushes the master cylinder piston through the worm wheel transmission pair and the ball screw transmission pair, so that it can be telescopically moved in the master cylinder to generate and release braking pressure.

[0009] The present invention also discloses an integrated self-locking braking method, which is based on the above-mentioned integrated self-locking braking system.

[0010] The present invention also discloses a data control system of a wire-controlled self-locking brake master cylinder system, and the data control system comprises the above-mentioned integrated self-locking brake system. Beneficial Effects

[0011] The present invention is electronically controlled by the vehicle control center, does not require a brake pedal mechanism, and the transmission system adopts a worm gear transmission pair and a ball screw transmission pair, so that the entire brake mechanism is small in size and compact in structure, which reduces the occupied space and reduces the manufacturing cost.

[0012] The brake-by-wire master cylinder system has fast response, high precision, and high load capabilities, enabling rapid braking in emergency situations;

[0013] Improved braking accuracy and increased safety are achieved through learning controller references. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the integrated self-locking brake system of the present invention;

[0015] Figure 2 It is a left view of the integrated self-locking brake system of the present invention.

[0016] In the figure: 1. motor assembly, 2. main housing, 3. worm gear, 4. master cylinder, 5. worm, 6. fluid storage pot, 7. master cylinder push rod, 8. master cylinder push rod displacement sensor, 9. pressure sensor. DETAILED DESCRIPTION Example 1

[0017] See also Figure 1-2The present invention discloses an integrated self-locking brake system, including a motor assembly 1, a main housing 2, a transmission mechanism, a master cylinder 4, and a liquid storage pot 6, wherein the motor assembly includes a motor and a motor control unit, and the motor control unit is integrated at the rear of the motor; the transmission mechanism includes a worm wheel 3, a worm 5, a worm wheel shaft, and a master cylinder push rod 7, wherein the worm and the worm wheel are meshed to form a worm gear transmission pair, the worm wheel shaft and the master cylinder push rod and the ball constitute a ball screw transmission pair, and the worm wheel is fixedly matched with the worm wheel shaft; the master cylinder is fixedly connected to the main housing by bolts, and a master cylinder piston is matched in the master cylinder, the master cylinder piston is slidably matched with the master cylinder, and is sealed by a sealing ring, the interior of the master cylinder piston is a high-pressure chamber, and the exterior of the master cylinder piston is in contact with the master cylinder push rod; the output torque of the motor pushes the master cylinder piston through the worm gear transmission pair and the ball screw transmission pair, and the master cylinder piston telescopes and moves in the master cylinder to generate and release braking pressure; a master cylinder push rod displacement sensor 8 is installed at the connection between the main housing and the master cylinder to measure the moving distance of the master cylinder push rod;

[0018] The high-pressure chamber is communicated with the fluid reservoir, and the high-pressure chamber is also communicated with the wheel cylinders of the four tires through the hydraulic brake pipeline; a pressure sensor 9 is installed in the fluid reservoir, and the pressure sensor is used to detect the brake fluid pressure inside the fluid reservoir and the master cylinder; the motor is fixedly installed on the main housing, and the motor control unit is integrated at the rear of the motor; the motor main shaft is connected to the worm through a coupling; the worm is meshed with the worm wheel to form a worm gear transmission pair; the worm wheel shaft is a hollow structure, the inner hole of the worm wheel is fixedly matched with the outer circle of the worm wheel shaft, the worm wheel shaft is installed in the main housing through a bearing, and the worm The wheel axle can rotate with the worm gear; the center of the worm gear shaft is processed with a trapezoidal internal thread; the center of the worm gear shaft is matched with a master cylinder push rod, and the outer side of the master cylinder push rod is processed with a trapezoidal external thread. The trapezoidal internal thread at the center of the worm gear shaft, the trapezoidal external thread on the outer side of the master cylinder push rod and the ball cooperate to form a ball screw thread pair; the master cylinder push rod adopts a ball screw, and the reverse efficiency is extremely low; such a structure can also make the entire brake mechanism compact and reduce the occupied space; the front end of the master cylinder push rod contacts the master cylinder piston, and the forward movement of the master cylinder push rod pushes the master cylinder piston to compress the brake fluid in the master cylinder; the motor master The rotation of the shaft drives the worm to rotate, the worm drives the worm wheel to rotate, the worm wheel shaft rotates with the worm wheel, and the rotation of the worm wheel shaft is converted into the linear motion of the master cylinder push rod and pushes the master cylinder piston to move linearly; when the motor outputs positive torque, the master cylinder push rod moves forward, pushing the master cylinder piston to compress the brake fluid in the master cylinder to generate brake pressure. When the motor no longer outputs torque, due to the extremely low reverse efficiency of the ball screw thread pair and the self-locking characteristics of the worm gear, the master cylinder push rod will not be able to automatically reset under the action of the hydraulic pressure. The motor must apply reverse torque to pull the master cylinder push rod back. When the system determines that the brake needs to be released, the electric The sub-signal controls the motor to output a reverse torque, the master cylinder push rod retreats, and the master cylinder piston retreats under the action of the high pressure of the brake fluid in the high-pressure chamber of the master cylinder, releasing the braking pressure; the motor is fixedly mounted on the main housing, and the motor control unit is integrated behind the motor; the motor control unit is the core of the brake master cylinder, responsible for processing all electronic signals related to braking, and collecting various information such as wheel speed sensors and steering angle sensors, calculating the optimal braking force of each wheel according to the vehicle's driving status, and sending instructions to the motor to implement braking; the wire-controlled self-locking brake master cylinder system is controlled by the vehicle control system. Example 2

[0019] Based on Example 1, the present invention discloses a braking method of an integrated self-locking braking system, which includes a service braking method and a parking braking method.

[0020] Driving braking method: The autonomous logistics vehicle senses the surrounding environment through the sensors it carries, obtains information such as the vehicle's position, speed, and the distance and speed of obstacles, and transmits it to the vehicle control system. The vehicle control system controls the motor of the brake master cylinder system through electronic signals. When the system determines that braking is required, the electronic signal controls the motor to output a positive torque, the master cylinder push rod moves forward, pushes the master cylinder piston to compress the brake fluid in the master cylinder, builds up braking pressure, and then pushes the wheel cylinder piston, causing the brake caliper to clamp the brake disc to generate friction and slow down the vehicle; when the system determines that the brakes need to be released, the electronic signal controls the motor to output a reverse torque, the master cylinder push rod retreats, and the master cylinder piston retreats under the action of the high pressure of the brake fluid in the high-pressure chamber of the master cylinder, releasing the braking pressure, and then the wheel cylinder piston retreats, and the brake caliper releases the brake disc to release the brake;

[0021] Parking brake method: the vehicle control system receives the parking brake electronic signal, the motor outputs positive torque, drives the worm, worm wheel, gear shaft, master cylinder push rod and master cylinder piston to the predetermined position, and after the braking pressure required for parking is established, the motor stops outputting torque; at this time, due to the extremely low reverse efficiency of the ball screw and the lead angle of the worm is smaller than the equivalent friction angle between the worm wheel and the worm, self-locking is formed, and the hydraulic pressure of the brake master cylinder cannot drive the worm to rotate through the reverse action of the master cylinder push rod, so that the motor applies power to push the master cylinder piston push rod to establish braking pressure and stop rotating, and the mechanical locking braking pressure remains unchanged; the motor does not need power at this time, that is, it can maintain the braking pressure and maintain the braking state to achieve parking braking. Example 3

[0022] The present invention also discloses a data control system for a wire-controlled self-locking brake master cylinder system. The integrated self-locking brake system described in Embodiment 1 of the data control system comprises a data acquisition module, a data processing module and a data execution module; the information acquisition module comprises a master cylinder push rod displacement sensor and a pressure sensor, and the data processing module and the data execution module are integrated in a motor control unit; the vehicle parameters acquired by the data acquisition module include braking intensity, battery state of charge and vehicle speed, and the above parameters are input into a learning controller for learning, thereby outputting a proportional coefficient between the motor force and the total braking force; the fuzzy rules between the braking intensity, battery state of charge, vehicle speed and proportional coefficient are determined in combination with the structural principle of the learning controller, thereby designing the learning controller; the real-time running vehicle conditions, power battery and braking intensity acquired by the sensor are used as inputs of the learning controller, the proportional coefficient between the motor force and the total braking force is learned and output from the learning controller, and the data processing module compares the proportional coefficient with the current motor maximum braking force proportional coefficient to output the required braking reference value to the data execution module, thereby achieving precise braking of the vehicle; due to the addition of the learning controller, the braking accuracy of the vehicle is more accurate, and the safety performance of the vehicle is improved;

[0023] When the vehicle control system determines that braking is needed, it controls the brake master cylinder system through electronic signals. The motor of the brake master cylinder system outputs a positive torque. The rotation of the motor main shaft drives the worm to rotate, and the worm drives the worm wheel to rotate. The worm wheel shaft rotates with the worm wheel. The rotation of the worm wheel shaft is converted into a forward linear motion of the master cylinder push rod through the ball screw pair. The forward movement of the master cylinder push rod pushes the master cylinder piston to compress the brake fluid in the master cylinder, thereby establishing braking pressure, and then pushing the wheel cylinder piston to clamp the brake caliper to generate friction and slow down the vehicle. During this period, the master cylinder push rod displacement sensor collects the movement distance of the master cylinder push rod and feeds it back to the data processing module. The data processing module converts the displacement data into an electrical signal and sends it to the data analysis module. The data analysis module combines the steering data and the vehicle speed data, and optimizes the steering and rotation speed of the motor through precise comparison and calculation, so that the master cylinder push rod obtains the optimal transmission torque and transmission speed, and obtains the best braking effect.

[0024] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. An integrated self-locking brake system, comprising a motor assembly, a main housing, a transmission mechanism, a master cylinder, and a fluid reservoir, characterized by: The motor assembly includes a motor and a motor control unit, and the motor control unit is integrated at the rear of the motor; the transmission mechanism includes a worm, a worm wheel, a worm wheel shaft, and a master cylinder push rod, wherein the worm and the worm wheel are meshed to form a worm wheel transmission pair, the worm wheel shaft and the master cylinder push rod and the ball constitute a ball screw transmission pair, and the worm wheel is fixedly matched with the worm wheel shaft; the master cylinder and the main housing are fixedly connected by bolts, and a master cylinder piston is matched in the master cylinder, and the master cylinder piston is slidably matched with the master cylinder body and is sealed with a sealing ring, the interior of the master cylinder piston is the master cylinder high-pressure chamber, and the outside of the master cylinder piston is in contact with the master cylinder push rod; the output torque of the motor pushes the master cylinder piston to move telescopically in the master cylinder through the worm wheel transmission pair and the ball screw transmission pair, thereby generating and releasing braking pressure; the rotation of the worm wheel shaft is converted into linear motion of the master cylinder push rod and pushes the linear motion of the master cylinder piston; a master cylinder push rod displacement sensor is installed at the connection between the main housing and the master cylinder, and the liquid storage A pressure sensor is installed in the pot, and the liquid storage pot is communicated with the high-pressure chamber of the master cylinder; the motor is fixedly installed on the main housing, and the main shaft of the motor is connected to the worm through a coupling; the worm is meshed with the worm wheel to form a worm gear transmission pair; the worm wheel shaft is a hollow structure, the inner hole of the worm wheel is fixedly matched with the outer circle of the worm wheel shaft, the worm wheel shaft is installed in the main housing through a bearing, and the worm wheel shaft rotates with the worm wheel; a trapezoidal internal thread is machined at the center of the worm wheel shaft; a trapezoidal external thread is machined on the outside of the master cylinder push rod, and the trapezoidal internal thread in the center of the worm wheel shaft, the trapezoidal external thread on the outside of the master cylinder push rod and the ball cooperate to form a ball screw thread pair; the front end of the master cylinder push rod is in contact with the master cylinder piston; the motor control unit is responsible for processing all electronic signals related to braking, collecting information from wheel speed sensors and steering angle sensors, calculating the optimal braking force for each wheel according to the vehicle's driving status, and sending instructions to the motor to implement braking.

2. An integrated self-locking brake system according to claim 1, characterized in that: the rotation of the motor main shaft drives the worm to rotate, the worm drives the worm wheel to rotate, and the worm wheel shaft rotates with the worm and worm wheel; when the motor outputs positive torque, the master cylinder push rod moves forward, pushing the master cylinder piston to compress the brake fluid in the master cylinder to generate braking pressure.

3. A control method for an integrated self-locking brake system, the control method being based on the integrated self-locking brake system according to claim 1, characterized in that: When the vehicle control system determines that braking is needed, it controls the brake master cylinder system through electronic signals. The motor of the brake master cylinder system outputs a positive torque. The rotation of the motor main shaft drives the worm to rotate, and the worm drives the worm wheel to rotate. The worm wheel shaft rotates with the worm wheel. The rotation of the worm wheel shaft is converted into forward linear motion of the master cylinder push rod through the ball screw pair. The forward movement of the master cylinder push rod pushes the master cylinder piston to compress the brake fluid in the master cylinder, thereby establishing braking pressure, and then pushing the wheel cylinder piston to clamp the brake caliper to generate friction and slow down the vehicle. During this period, the master cylinder push rod displacement sensor collects the movement distance of the master cylinder push rod and feeds it back to the data processing module. The data processing module converts the displacement data into an electrical signal and sends it to the data analysis module. The data analysis module combines the steering data and the vehicle speed data, and optimizes the steering and rotation speed of the motor through calculation, so that the master cylinder push rod obtains the optimal transmission torque and transmission speed.

4. A data control system for a wire-controlled self-locking brake master cylinder system, the data control system comprising the integrated self-locking brake system according to claim 1, including a data acquisition module, a data processing module and a data execution module; the data acquisition module comprises a master cylinder push rod displacement sensor and a pressure sensor, the data processing module and the data execution module are integrated in a motor control unit; the characteristics are: The vehicle parameters collected by the data acquisition module include braking intensity, battery state of charge and vehicle speed, and the vehicle parameters are input into the learning controller for learning, thereby outputting the proportional coefficient of the motor braking force to the total braking force; The fuzzy rules among the braking intensity, battery state of charge, vehicle speed and proportional coefficient are determined in combination with the structural principle of the learning controller, so as to design the learning controller. The real-time vehicle operating conditions, power battery and braking intensity collected by sensors are used as inputs of the learning controller, and the proportional coefficient between the motor force and the total braking force is learned and output from the learning controller. The data processing module compares the proportional coefficient with the current motor maximum braking force proportional coefficient and outputs the required braking reference value, which is transmitted to the data execution module, so as to achieve precise braking of the vehicle. When the vehicle control system determines that braking is required, the brake master cylinder system is controlled by electronic signals, and the motor of the brake master cylinder system outputs a positive torque. The rotation of the motor main shaft drives the worm to rotate, and the worm The worm gear is driven to rotate, and the worm gear shaft rotates with the worm gear. The rotation of the worm gear shaft is converted into the forward linear motion of the master cylinder push rod through the ball screw pair. The forward movement of the master cylinder push rod pushes the master cylinder piston to compress the brake fluid in the master cylinder, thereby establishing braking pressure, and then pushes the wheel cylinder piston, causing the brake caliper to clamp the brake disc to generate friction, thereby slowing down the vehicle. During this period, the master cylinder push rod displacement sensor collects the moving distance of the master cylinder push rod and feeds it back to the data processing module. The data processing module converts the displacement data into an electrical signal and sends it to the data analysis module. The data analysis module combines the steering data and the vehicle speed data, and optimizes the steering direction and rotation speed of the motor through the data processing of the learning controller and the data processing module, so that the master cylinder push rod obtains the optimal transmission torque and transmission speed.

Images