Odd-Number Vane Motor for Down-The-Hole Hammer Torque
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Solution Overview
Problem
Existing rotary devices for down-the-hole hammers face inefficiencies in compactness and torque delivery due to limited vane area and uneven resistance handling during rock drilling.
Innovation Solution
A vane motor with an odd integer number of drive lobes and working chambers, allowing for improved hydraulic stability and balanced operation by pressurizing an odd number of vanes in each chamber, eliminating the need for spring components and optimizing vane arrangement for larger effective areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vane motor with even number of drive lobes (e.g., two) is used, then the structure is simple and easy to manufacture, but the hydraulic stability is insufficient and torque delivery is limited
Solution Approach 1:
The patent applies asymmetry by using an odd number of drive lobes (3, 5, or 7) instead of the conventional even number (2). This asymmetric configuration creates uneven distribution of vanes in working chambers, ensuring that at least one vane is always in a pressurized state, thereby improving hydraulic stability and torque delivery without significantly increasing structural complexity
2Power
If the number of drive lobes is increased to improve torque, then the effective vane area increases, but the machine size and weight increase
Solution Approach 1:
The patent applies local quality by optimizing the distribution and positioning of vanes within each working chamber. By using an odd number of drive lobes, the vanes are arranged to maximize their effective area in the pressurized regions, thereby increasing torque output without proportionally increasing the overall machine size and weight
3Ease of operation
If spring components are added to pressurize vanes at low speed, then low-revolution performance improves, but the device complexity and maintenance requirements increase
Solution Approach 1:
The patent applies self-service by designing a system where the odd-numbered drive lobes and vanes automatically ensure continuous pressurization through their geometric arrangement. The hydraulic system itself provides the necessary pressurization force without requiring external spring components, thereby improving low-revolution performance while reducing device complexity and maintenance requirements
Data Source
AI summary
The invention relates to a rotary device (101) for a down-the-hole hammer (1), which rotary device is accommodated in a rotation motor housing (3) and mounted behind a drill housing (2) for transferring a torque to a drill bit (8) and a pressurized drive fluid (22) to a striking mechanism (4) for the drill bit. The rotary device includes a cam curve with a plurality of drive lobes (28:1-28:3) and working chambers (30:1, 30:2, 30:3) along a circumference in the rotation motor housing (3), a rotor disc (38) carrying a plurality of radially movable vanes (40:1-40:12), which are accommodated in piston tracks (41:1-41:12) in the rotor disc. Characteristics of the rotary device are that it includes; an odd integer of a number of drive lobes (28:1-28:3), which is equal to or higher than three; an odd integer of a number of working chambers (30:1, 30:2, 30:3), which is equal to or higher than three; an odd integer of a number of vanes (40:1-40:12), which is equal to or higher than three, and wherein said number of vanes are simultaneously pressurized in each working chamber (30:1, 30:2, 30:3).