Electric Steady Rest with Force Sensor for Leak-Free Clamping
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Solution Overview
Problem
Hydraulically operated steady rests for centric clamping of workpieces face issues with leaks leading to loss of clamping force, and existing electric motor-driven bezels lack effective clamping security and force monitoring.
Innovation Solution
A bezel with an electric motor-driven rod and spindle system, incorporating a planetary gear, spring element, and force sensor, allows for precise adjustment and monitoring of clamping force, enabling secure centric clamping and integration with automated machining centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic system is used to operate the steady rest, then the clamping force can be maintained, but leaks occur leading to loss of clamping force
Solution Approach 1:
The patent replaces the hydraulic system with an electric motor-driven system. The electric motor (7) directly drives the spindle (9) through a spindle member (10) to adjust the holding members (3, 30), eliminating hydraulic fluid and its associated leak problems while maintaining reliable clamping force control through electrical actuation.
2Ease of operation
If a hydraulic system is used, then the steady rest can be operated, but the device size increases due to pressure medium chamber and pressure piston
Solution Approach 1:
The patent substitutes the bulky hydraulic components (pressure medium chamber, pressure piston) with a compact electric motor (7) and direct-drive spindle mechanism. This electric drive system achieves the same operational functionality with significantly reduced volume, making the steady rest more compact while maintaining ease of operation through electrical control.
3Volume of moving object
If an electric motor is used to adjust holding members, then the bezel becomes more compact, but clamping security and force monitoring are compromised
Solution Approach 1:
The patent incorporates a force sensor (19) that provides feedback on the clamping force to a control unit (18). The control unit monitors the force sensor signals and can control the electric motor (7) as a function of these signals, ensuring that clamping security is maintained through active monitoring and closed-loop control, thereby resolving the concern about reduced reliability with electric actuation.
4Ease of manufacture
If a standardized linear motor is used for rod adjustment, then manufacturing cost is reduced, but integration with existing steady rests may be limited
Solution Approach 1:
The patent segments the drive system into modular components: a standardized linear motor or spindle mechanism for rod adjustment, a separate force sensor (19), and a control unit (18). This modular segmentation allows the core adjustment mechanism to be a cost-effective standardized component while maintaining adaptability through the configurable control system that can integrate with various existing steady rest configurations.
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
Ensures reliable clamping security, reduces bezel size, and facilitates automation by providing a compact, cost-effective solution for secure and monitored clamping force, suitable for retrofitting existing systems.
Implementation Method 1
a spring element is arranged on the axially rear side between the spindle member and the steady rest body, which is preferably formed as a spring assembly having a plurality of plate springs. This set of disc springs serves as a clamping force accumulator and as a clamping force safeguard.
Implementation Method 2
A bezel operated with an electric motor is known from EP 2 353 777 A1... The electric motor is operated with the usual low voltage.
Implementation Method 3
a gear, preferably a planetary gear, is provided between the spindle member and the spindle
Implementation Method 4
the rod is formed as a spindle and can be adjusted by a spindle member that can be driven by means of the electric motor. The rotary movement of the electric motor does not first have to be converted into a linear movement in order to adjust the rod, since this is now automatically adjusted axially by the spindle thread formed between the spindle and the spindle member.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a steady rest (1) for the central clamping of workpieces, comprising three holding members (3, 30) arranged in one plane and having rollers (2), of which the two outer holding members (30) are associated with clamping arms (4) that are pivotable about pivot pins (6) arranged in the steady rest body (5), and the middle holding member (3) is adjustable in a linear direction relative to the workpiece. At least one holding member (3) is adjustable by means of an electric motor (7).