Guide Bearing Centering Chambers for Anti-Seizing Percussion Pistons
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Solution Overview
Problem
Percussion devices with high-mass striking pistons, especially when used at non-vertical positions, face intense friction and risk of seizing due to inadequate guidance, leading to blockages or permanent damage, and existing solutions fail to ensure proper centering and hydraulic flow effectively.
Innovation Solution
Incorporating a centering device with centering chambers connected to a high-pressure fluid supply and evacuation grooves connected to a low-pressure circuit around the guide bearings, which maintains a hydraulic film and prevents direct contact between the striking piston and guide surfaces, ensuring proper alignment and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high-mass impact piston is used to increase striking force, then the power and effectiveness of the percussion tool is improved, but the risk of the impact piston seizing on the guide surfaces increases due to intense friction
Solution Approach 1:
The patent applies hydraulic principles by introducing a hydraulic film between the impact piston and guide surfaces through controlled fluid pressure. The hydraulic circuit applies pressure differentials across the guide surfaces, creating a fluid film that separates the impact piston from the guide surfaces, thereby eliminating direct metal-to-metal contact and reducing friction for high-mass pistons
2Reliability
If hydraulic flow is applied between the impact piston and guide surfaces to reduce friction, then the risk of seizing is reduced, but proper centering of the striking piston relative to the guide bearings is not achieved
Solution Approach 1:
The patent applies local quality by creating different pressure zones at different locations of the guide surfaces. The hydraulic circuit applies pressure differentials specifically at the axial ends of each guide surface, creating localized high-pressure zones that generate hydraulic lift and centering forces. This localized pressure application ensures both separation from the guide surfaces and proper centering of the impact piston
3Ease of operation
If the impact piston is allowed to contact the guide surfaces for guidance, then the guidance function is achieved, but intense friction occurs leading to seizing and potential damage
Solution Approach 1:
The patent introduces a hydraulic film as an intermediary between the impact piston and guide surfaces. This fluid intermediary maintains the guidance function by keeping the impact piston properly positioned and centered relative to the guide bearings, while simultaneously eliminating direct contact and the associated friction and seizing risks
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 solution effectively prevents seizing of the striking piston by maintaining a hydraulic film and ensuring proper centering, even with high-mass pistons, reducing friction and preventing damage during operation.
Implementation Method 1
Hydraulic flow is achieved by applying a pressure differential to the axial ends of each guide surface, for example, by connecting one side of each guide surface to a high-pressure fluid supply circuit and the other side to a low-pressure circuit. Such an arrangement generates hydraulic flow in each guide bearing, which promotes the formation of a hydraulic film between the impact piston and each guide bearing.
Implementation Method 2
at least one guide bearing has a centering device configured to center the impact piston in the piston cylinder, the centering device comprising: a plurality of centering chambers formed in the guide surface of at least one guide bearing and distributed around the impact piston, each centering chamber being fluidly connected to the high-pressure fluid supply circuit, and a plurality of drainage grooves formed in the guide surface of at least one guide bearing, each drainage groove being located near at least one of the centering chambers and being fluidly connected to the low-pressure circuit
Data Source
Figure 1~2
Figure 3~4
AI summary
This percussion apparatus (2) comprises a striking piston (5) mounted with the ability to move inside a piston cylinder (4) and designed to strike a tool (6); and a guide bearing (15) comprising a guide surface (16) configured to guide the striking piston (5) during the movements of the striking piston (5) in the piston cylinder (4). The guide bearing (15) comprises a centring device (17) configured to centre the striking piston (5) in the piston cylinder (4), the centring device (17) comprising centring chambers (18) formed in the guide surface (16) and distributed around the striking piston (5), each centring chamber (18) being fluidically connected to a high-pressure fluid feed circuit (12), and at least one discharge groove (22) formed in the guide surface (16) of the guide bearing (15) and situated near at least one of the centring chambers (18), the at least one discharge groove (22) being fluidically connected to a low-pressure circuit (13).