Percussion Device Parabolic Guide Surfaces
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Solution Overview
Problem
Existing impact devices suffer from radial contact between the percussion piston and the percussion mechanism housing, leading to wear and damage, as well as excessive oil leakage due to insufficient load-bearing capacity of the oil film, especially when the piston is misaligned or subjected to lateral forces.
Innovation Solution
The impact device features guide surfaces with a non-linearly increasing inner diameter, specifically a parabolic shape, which enhances the load-bearing capacity of the oil film, preventing contact between the piston and the housing and reducing wear by maintaining a stable lubricating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the guide surfaces are designed with a constant diameter (cylindrical shape), then the manufacturing is simple, but the load-bearing capacity of the oil film is insufficient causing radial contact and wear
Solution Approach 1:
The guide surfaces are designed with a parabolic curvature profile instead of a cylindrical straight profile. The inner diameter of the guide surface increases parabolically in the axial direction, creating a curved geometry that enhances oil film pressure distribution and load-bearing capacity while preventing radial contact between piston and housing.
Solution Approach 2:
The diameter parameter of the guide surface is changed from constant (cylindrical) to variable (parabolic increase in axial direction). This parameter change optimizes the oil film thickness distribution and pressure characteristics, thereby improving the load-bearing capacity of the oil film without causing radial contact.
2Reliability
If the guide surfaces have a parabolic shape with non-linearly increasing diameter, then the load-bearing capacity of the oil film increases preventing radial contact, but the manufacturing complexity increases
Solution Approach 1:
The guide surface diameter parameter varies parabolically along the axial direction, creating a smooth curved profile that enhances oil film load-bearing capacity. This continuous parameter change provides optimal lubrication conditions while maintaining manufacturability through standard machining processes capable of producing parabolic profiles.
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 configuration effectively prevents radial contact and wear, increases the service life of the hammer mechanism, and reduces oil leakage by maintaining a stable oil film, even under misalignment or lateral forces.
Implementation Method 1
friction and adhesion forces between the oil and the component surfaces cause additional oil transport through the gap
Implementation Method 2
friction and adhesion forces between the oil and the component surfaces cause additional oil transport through the gap
Implementation Method 3
The oil pressure in the gap exerts a radial force on the piston, pushing it away from the bore wall and centering it
Data Source
Figure 1
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AI summary
The invention relates to a percussion device comprising a percussion mechanism housing which has a receiving bore in which a percussion piston is mounted such that it is movable along the longitudinal axis, wherein at least one percussion mechanism guide surface having an inner diameter is formed in the receiving bore and at least one percussion piston guide surface having an outer diameter is formed on the percussion piston. In order to avoid radial contact between the percussion piston and the percussion mechanism housing as far as possible, to reduce the volume of oil leakage through the gap of the guide surface and to prevent wear on the guide surfaces and on the lands between the seals, according to the invention the percussion mechanism guide surface has, at least in some regions, an inner diameter that increases non-linearly in the axial direction and/or the percussion piston guide surface has an outer diameter that decreases non-linearly in the axial direction.