Symmetrical Elevator Braking Torque Distribution
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Solution Overview
Problem
Elevator drive braking systems face safety concerns due to reduced frictional force from wear or contamination, leading to potential slipping and failure, which can compromise the security of the elevator operation.
Innovation Solution
The elevator drive incorporates a braking device with a symmetrical arrangement of braking units on both sides of the traction wheel, featuring a movable relative element that automatically shifts to a braking position to maintain frictional force, and a sensor system to monitor and detect malfunctions, ensuring a safety reserve and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frictional force between brake discs and armature disks is reduced due to wear or contamination, then braking effectiveness decreases, but safety of the elevator drive is compromised
Solution Approach 1:
The patent introduces a monitoring device that detects frictional force between brake discs and armature disks before safety is compromised. When wear or contamination reduces frictional force below a threshold, the system triggers an alarm or stops operation preemptively, preventing safety failures rather than reacting after they occur.
Solution Approach 2:
The monitoring device continuously measures the frictional force and provides feedback to the control system. This real-time feedback enables dynamic adjustment of braking parameters or triggers maintenance alerts, ensuring braking effectiveness is maintained throughout the component lifecycle.
2Reliability
If braking devices are arranged on both sides of the traction wheel, then torque transmission risk is reduced, but device complexity increases
Solution Approach 1:
The braking system is segmented into two independent braking devices positioned on opposite sides of the traction wheel. Each braking device operates independently to provide braking torque, so that if one fails, the other can still safely stop the elevator. This segmentation distributes the safety-critical function across multiple independent components.
Solution Approach 2:
The patent employs symmetrical arrangement of braking devices on both sides of the traction wheel, which actually reduces asymmetry in the system. This symmetrical configuration balances the torque transmission paths and reduces stress concentration on the drive shaft, while the monitoring system treats each side independently for enhanced reliability.
3Object-affected harmful factors
If armature disks are designed in three parts to reduce noise, then noise is reduced, but structural complexity increases
Solution Approach 1:
Each armature disk is segmented into three separate parts or segments rather than being a single solid disk. This segmentation allows the disk to flex and absorb impact noise during braking operations, reducing noise transmission to the elevator car and shaft while maintaining the necessary structural integrity for braking function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the risk of drive shaft failure, maintains effective braking, and allows for continuous monitoring of the braking system's function, enhancing safety and operational reliability by providing a safety reserve and detecting potential malfunctions.
Implementation Method 1
The frictional forces acting in these contacts counteract a rotation between the brake disc, which is rotationally fixed to the working shaft, and the housing or the armature disks connected to it in a rotationally fixed manner and thus brake the working shaft.
Implementation Method 2
To release the brake, the armature disks are released electromagnetically against the springs.
Implementation Method 3
By means of a spring, axially displaceable armature disks are biased against the brake disks with a normal force
Data Source
Figure 1a~2b
Figure 3a~4
Figure 5~6
AI summary
A lift drive (20) serves to drive and to detain a lift car, and it essentially contains a traction wheel (22) for transmitting a driving or detaining force to the lift car, a motor (21) for driving the traction wheel (22), and a braking arrangement for detaining the traction wheel (22). A drive shaft (2) connects the traction wheel, the motor and the braking arrangement to one another. The braking arrangement contains at least two braking devices (24.1, 24.2), wherein, according to the invention, the traction wheel (22) is arranged between the braking devices (24.1, 24.2). This is advantageous, since the braking torques (MB1,2) which are transmitted by the traction wheel (22) to the braking devices (24.1, 24.2) are divided. In the case of an advantageous, symmetrical division of the braking devices (24.1, 24.2), half on either side of the traction wheel, a torque which is to be transmitted is reduced by half in the drive shaft (2). A risk of failure or risk of breakage of the drive shaft (2) is thereby significantly reduced. In addition, during a possible failure of the drive shaft (2), there continues to be a braking function, since the braking devices (24.1, 24.2) are distributed on both sides of the traction wheel (22).