Views:28 Author:Site Editor Publish Time: 2020-12-09 Origin:Site
Welcome our topic for today is about electric parking brake in this discussion we covered:
1. introduction of EPB:
2. EPB components
3. working principle
4. types of EPB
5. benefits and disadvantages
1. Introduction of EPB
The electric park brake functions as a conventional hydraulic brake for standard service brake applications and as an electric brake for parking and emergency braking.
Electric park brake is a caliper with an additional motor that operates the parking brake. The EPB system is electronically controlled and consists of the EPB switch, the EPB caliper and the electronic control unit(ECU). The electric parking brake or the EPB is an advanced version of conventional parking brake or handbrake. Sometimes people also refer to this system as electronic parking brake.
Technically the system is a subpart of brake by wire system. The main function of parking brakes is to avoid motion of vehicle when parked. In addition, these brakes also play an important role in
avoiding backward motion of vehicle which resumed moving on a slope.
Generally parking brakes operate only on the rear wheels of a vehicle. EPB functionality relies on four elements: control switched, a wheel speed sensor, a force sensor, electric motor. Together, these monitor a variety of input signals and determine when to apply or release the brakes.
Screw Technology Co., Ltd. has passed IATF16949 Certification, it means our products are directly related to the production of automobiles, have processing and manufacturing capabilities, and achieve value-added products through the realization of this capability. It proves that our product quality is the same level as HIWIN, TBI, NSK, NTN, etc. We are not only ball screw manufacturer, ball screw supplier, but also provide one stop solutions to our customers.
Electronic brake module
Actuator or electric motor
3. Working principle
Conventional parking brakes employ a cable that connects handbrake lever and brake shoes. When the driver operates the lever, tension in the cable Increases. Thereby forcing the brake shoe (or pads) on brake drum (or disc). Thus wheels cannot move further. When the driver operates the switch, it sends a command to module which senses that parking brakes are required to be operated. Later this module commands the actuators or electric motors installed in the brake calipers to operate. Thus brake pads are forced on the disk thereby restricting the movement of wheels.
Due to the use of electronic components the operation of this system is almost instantaneous and efficient. Also it improves the reliability of braking because of the absence of mechanical connection. This brake deactivates automatically when the driver presses the accelerator pedal. Some vehicle manufacturers also integrate assist function with this system.
4. Types of EPB:
a) Cable pull system
b) Electro hydraulic system with ESP
c) Electric parking brake drive by wire system
The cable pull system is simply a development of a traditional lever and cable method.
As the switch is operated a motor or motors pull the cable by either rolling it on a drum or using an internally threaded gear on a spiral attached to the cable.
The electronic parking brake module also known as the EPB actuator, is fitted to some Range Rover and Land Rover modules. The parking brake can be released manually on most vehicles. After removing a plastic cover or similar, pulling a wire cable loop will let off the brake.
Cable-Pull Systems (with parking brake lever)
Low cost at time system is installed to the vehicle cable pulls systems with parking brake lever
No driver assists fully manual
low reliability and safety due to driver in the loop.
Requires package space and interior.
Routing and adjustment of thick mechanical Bowden cable’s in production.
Aging of cables and poor clamp force stability over lifetime
Cable-pull Systems (with EPB actuator)
Driver assist functions
Small switch in interior
Parts cost and installation effort.
High technical effort for cable puller unit fixation and noise insulation.
Aging of cables and poor clamp for stability over lifetime. Brake is often overloaded.
Durability limitations at higher cable loads.
Low reliability due to sticking
Cables, single motor drive approach,
overloaded brake actuators, etc.
Electric-Hydraulic Caliper Systems
These types are usually employed as part of a larger control system such as an electronic stability program(ESP). When the driver presses the switch to activate the parking brake, the ESP unit automatically generates pressure in the braking system and presses the brake pads against the disc. The calipers are then locked in position by an electrically controlled solenoid valve.
The caliper remains locked without any need for hydraulic pressure. To release the brake, the ESP briefly generates pressure again, slightly more than was needed to lock the caliper, and the valve is released.
Electric Parking Brake drive by wire systems
The drive-by-wire system was developed by Continental. It uses an electric motor and gearbox to apply pressure on the pads and therefore onto the disc. A key component is the parking brake latch. This is like a ratchet and it prevents the pressure in the piston from rotating the motor and it therefore keeps the brakes applied.
Modular architecture, scalable clamp load and durability with reduced hysteresis
Significant weight savings compared to mechanical park brake systems to support enhanced fuel economy and reduced emissions
Vehicle coverage from small car to light trucks segments
Electronic control allows for integration with other safety technologies
Pioneered EPB technology in 2000 and now in fifth generation with more than 90 million EPB calipers on world roadways
The response time of this system is very short
The operation is highly reliable
Improves control of the vehicle while starting from standstill condition on a slope.
This system is costly
It needs a skilled professional for troubleshooting
Q：What is trapezoidal screw?A：Trapezoidal screw is a kind of lead screw. It is a trapezoidal screw thread. Generall, a 30-degree trapezoidal screw means that the angle of the thread section extension is 30 degrees. Trapezoidal screws are divided into left-handed, right-handed and bi-directional-handRead More
What are the advantages of linear modules? The linear module is an automatic transmission element, which uses timing belt or ball screw to drive the slider to move. It is usually composed of timing belt, ball screw, direct moving die, aluminum alloy profiles, ball screw bracket, coupling, motor, PhoRead More
We all know that linear guides are now an important part of mechanical equipment. Be careful when using linear guides. Many factors will affect the guides and make them fail during operation! Today I will introduce you to the influence of temperature on linear guides! The influence of temperature oRead More
The relationship between the pre-pressure of the ball screw and the load of the screw is mainly used for gap adjustment. If high precision is required, the pre-pressure should be increased accordingly, but it should not be too large, otherwise it will cause high temperature and reduced efficiency.Read More
What is the ball screw drive torque? How should this torque be calculated? The torque of the mechanical components is called the driving torque of the ball screw. The ball screw will produce a certain degree of torsional deformation under the action of torque. Torque is the basic load form of transmRead More
Features of Rotating SeriesZero clearance in spline rotation direction/high positioning accuracyThe contact angle between the nut and the steel ball is 40°, and the bearing DB type (back-to-back combination) design is adopted. Due to the wide span between the effective centers of the bead groove, thRead More