Spring Clamping Cylinder With Separated Actuation for Stable Chuck Force
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Solution Overview
Problem
Existing clamping devices for machine tools face issues with uncontrollable spring forces, high energy consumption, leakage, and wear due to the continuous supply of pressure medium, leading to heat generation and increased mass rotation, which complicates the maintenance of defined clamping forces during machining.
Innovation Solution
The clamping device separates the actuation module from the clamping cylinder during operation, using a spring-loaded system with roller bearings to maintain clamping force without continuous pressure, allowing for elastic retensioning and minimizing rotating mass and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic or pneumatic cylinders are used to operate the collet or chuck, then the necessary pressure is provided at all times, but significant leakage occurs from the rotary distributor, causing high energy consumption and heat generation
Solution Approach 1:
The system is divided into a stationary actuating module and a rotating clamping cylinder section. The actuating module remains stationary while the clamping cylinder rotates with the spindle, eliminating the need for a rotary distributor and associated leakage problems.
Solution Approach 2:
The clamping cylinder and its spring assembly are extracted as a separate rotating section from the stationary actuating module. This allows the spring-loaded clamping mechanism to operate independently during rotation without requiring continuous hydraulic or pneumatic pressure supply.
2Stability of the object's composition
If the cylinder and rotating feed section are firmly bolted together as a complete unit, then the mass rotates as a single unit, but the required rotating mass increases and energy consumption rises
Solution Approach 1:
The system separates the rotating mass into only the essential clamping cylinder and collet assembly, while the actuating module remains stationary. This segmentation minimizes the rotating mass and its associated moment of inertia, reducing energy consumption during acceleration and deceleration.
3Device complexity
If a single helical compression spring acts as a force accumulator surrounding the drawbar, then the structure is simple, but the spring force is difficult to control and only low clamping forces can be exerted
Solution Approach 1:
Multiple helical compression springs are arranged in parallel within the clamping cylinder, each contributing to the total clamping force. This configuration increases the available force while maintaining structural simplicity, and allows for better control of the spring force characteristics.
4Loss of energy
If the actuating module is designed to stand still during rotation, then contactless separation from the clamping cylinder is achieved, but the mechanism for transferring force during adjustment is more complex
Solution Approach 1:
Roller bearings serve as intermediaries to transfer the spring force from the stationary actuating module to the rotating clamping cylinder during adjustment operations. These roller bearings enable force transmission without permanent mechanical connection, allowing the actuating module to remain stationary while the clamping cylinder rotates.
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 design eliminates leakage and heat generation, reduces energy consumption, and minimizes rotating mass, ensuring stable clamping forces without continuous pressure supply, enhancing machining efficiency and reducing wear.
Implementation Method 1
a spring-loaded clamping cylinder for actuating clamping tools on lathes
Implementation Method 2
with a spring-loaded clamping cylinder
Implementation Method 3
using a spring-loaded system with roller bearings
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Clamping device (1), in particular for machine tools, which are provided, for example, with a power chuck (6) for holding a workpiece (4), the clamping jaws (134) of which can be actuated by means of the clamping device (1) via an axially adjustable draw tube (18) by means of an actuating module (3, 3', 3", 3'''), wherein the clamping device (1) has a force storage device (138) in a rotating clamping cylinder (2, 2', 2", 112) of a machine spindle (135) for maintaining the clamping force, in order to convert the adjustment movements into the axial adjustment movements of the draw tube (18) required for actuating the clamping jaws (134), which consists of pre-tensioned springs (9, 9', 9", 49) which are supported on an adjusting element (29) designed as a hollow shaft and provided with a radially outwardly projecting extension (31), wherein during the rotating operating state the rotating The clamping cylinder (2, 2', 2", 112) is separated from the actuating module (3, 3', 3", 3'').