Parking Brake Actuator With Hollow Shaft Tension Sensing
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Solution Overview
Problem
Existing actuator systems for motor vehicle parking brakes, particularly in agricultural vehicles, face challenges such as complexity, high cost, difficulty in assembly, mechanical performance issues, and lack of direct tension monitoring, leading to potential malfunctions and assembly problems.
Innovation Solution
A compact actuator system with a reduced number of parts, using a cycloidal reducer, a hollow shaft with a cam-shaped surface, and a position sensor to directly monitor cable tension through Belleville springs, ensuring reliable operation and direct load detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional actuator systems with multiple components are used, then the system can provide braking function, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the motor, reducer, cable tensioning mechanism, and sensor into a single integrated actuator assembly. The motor (1) and reducer (2) are coupled together, with the output shaft (4) directly connected to the cable (6) through the Belleville spring assembly (8, 9, 10), eliminating the need for separate mounting brackets, cable guides, and adjustment mechanisms found in traditional systems.
Solution Approach 2:
The actuator system performs multiple functions within a single device: the motor provides driving force, the reducer provides mechanical advantage, the Belleville springs provide cable tensioning and positioning, and the sensor monitors cable tension. This multi-functional integration replaces what would traditionally require separate components for each function.
2Reliability
If traditional actuator systems with multiple components are used, then the system can provide braking function, but the assembly difficulty increases
Solution Approach 1:
The patent combines the motor, reducer, cable tensioning mechanism, and sensor into a single integrated actuator assembly. The motor (1) and reducer (2) are coupled together, with the output shaft (4) directly connected to the cable (6) through the Belleville spring assembly (8, 9, 10), eliminating the need for separate mounting brackets, cable guides, and adjustment mechanisms found in traditional systems.
Solution Approach 2:
The Belleville springs (8) are pre-assembled between the support plate (7) and the cable (6) with pre-set compression, establishing the correct cable tension and positioning before final assembly. This preliminary configuration ensures proper mechanical relationships are maintained during installation and operation.
3Ease of operation
If traditional actuator systems are used, then the system can operate, but the mechanical performance consistency decreases due to play and component arrangement variability
Solution Approach 1:
The patent combines the motor, reducer, cable tensioning mechanism, and sensor into a single integrated actuator assembly. The motor (1) and reducer (2) are coupled together, with the output shaft (4) directly connected to the cable (6) through the Belleville spring assembly (8, 9, 10), eliminating the need for separate mounting brackets, cable guides, and adjustment mechanisms found in traditional systems.
Solution Approach 2:
The Belleville springs (8) are pre-assembled between the support plate (7) and the cable (6) with pre-set compression, establishing the correct cable tension and positioning before final assembly. This preliminary configuration ensures proper mechanical relationships are maintained during installation and operation.
4Ease of operation
If traditional actuator systems are used, then the system can operate, but the cable tension monitoring capability is lacking
Solution Approach 1:
The patent incorporates a sensor (12) that directly monitors the tension in the cable (6) and provides feedback to the control system. The sensor is positioned to detect the position of the output shaft (4) or the compression of the Belleville springs (8), providing real-time information about cable tension status and enabling the system to detect malfunctions or improper tensioning.
Solution Approach 2:
The output shaft (4) acts as an intermediary element that translates cable tension into a measurable position change. The cam-shaped surface (11) on the output shaft converts axial movement from cable tension into radial displacement that can be detected by the sensor (12), providing indirect but reliable tension measurement.
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
The system provides a simple, cost-effective, and reliable method to maintain consistent cable tension, ensuring correct operation and immediate detection of any issues, reducing assembly complexity and mechanical performance variability.
Implementation Method 1
a position sensor (52) and a control board; detecting a first position of the hollow shaft (41) by means of the position sensor (52); displacing the cable (54) by means of activation of the motor (21); detecting a second position of the hollow shaft (41) by means of the position sensor (52)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An actuator system, for example for controlling a parking brake of a motor vehicle, such as an agricultural vehicle, comprises a housing (20) containing an electric motor (21) and a reducer group (22) connected downstream of the electric motor (21), a hollow shaft (41) connected to the reducer group and displaceable longitudinally inside said housing (20) and, for example, a cable (54) to be operated, which is connected to the hollow shaft (41). The system also comprises a position sensor (52), which is located fixed inside the housing (20) and arranged facing said hollow shaft (41) for measuring a displacement of said hollow shaft (41).