Hydraulic Hammering Device Cushion Chamber Drain Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic hammering devices employing the 'front/rear chamber alternate switching method' experience cavitation and erosion due to rapid pressure variations in the front chamber, leading to inefficiencies and potential damage from shock pressure.
Innovation Solution
Incorporating a cushion chamber with a 'second drain circuit' that communicates hydraulic oil in the cushion chamber with a low pressure circuit through separate passages, reducing flow velocity and preventing cavitation, and using a copper alloy front-chamber liner with radial and axial communication passages to manage pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the front chamber is switched into communication with a low pressure circuit when the piston advances, then hammering efficiency is improved, but cavitation and erosion occur due to rapid pressure variations
Solution Approach 1:
The front chamber is divided into two separate chambers: a first chamber that communicates with the low pressure circuit during piston advancement, and a second chamber that maintains high pressure connection. This segmentation allows the system to achieve both improved hammering efficiency and prevention of cavitation by isolating the functions of each chamber.
Solution Approach 2:
A partition wall with a communication hole serves as an intermediary structure between the first and second chambers. This intermediary allows controlled pressure transmission while maintaining the functional separation needed to prevent cavitation and erosion, enabling the system to resolve the contradiction between efficiency improvement and harmful factor prevention.
2Object-affected harmful factors
If the front chamber is always in communication with a high pressure circuit, then cavitation and erosion are prevented, but hammering efficiency decreases due to resistance from hydraulic oil
Solution Approach 1:
By segmenting the front chamber into first and second chambers with distinct pressure circuit connections, the system can maintain high pressure connection in the second chamber for cavitation prevention while allowing the first chamber to connect to low pressure circuit for improved hammering efficiency.
Solution Approach 2:
Different regions of the front chamber are assigned different pressure conditions: the second chamber maintains high pressure quality for protection against cavitation, while the first chamber uses low pressure quality for enhanced hammering performance. This local differentiation resolves the contradiction between protection and efficiency.
3Reliability
If a cushion chamber is added to prevent piston striking, then piston protection is improved, but device complexity increases
Solution Approach 1:
The cushion chamber function is merged with the existing front chamber structure by utilizing the second chamber as the cushion chamber. This integration provides piston protection without requiring a completely separate cushioning system, thereby limiting the increase in device complexity.
Solution Approach 2:
The second chamber serves multiple functions: it maintains high pressure connection for cavitation prevention, acts as a cushion chamber for piston protection, and provides structural support. This multi-functionality achieves piston protection while minimizing additional complexity by making one component serve multiple purposes.
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 suppresses cavitation and heat generation, reduces the risk of 'galling' and erosion, and maintains hammering efficiency by managing pressure and temperature within the hydraulic hammering device.
Implementation Method 1
a rapid variation in the pressure of hydraulic oil is caused in the front chamber... a lot of minute bubbles, that is, cavitation, becomes likely to be produced in hydraulic oil
Implementation Method 2
a hydraulic chamber space formed to the front-chamber liner as a cushion chamber, the hydraulic chamber space communicating with the front chamber to be filled with hydraulic oil
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A hydraulic hammering device which uses a scheme in which a front chamber is switched into communication with a low-pressure circuit when a piston advances, wherein occurrences of "galling" to the piston at a sliding contact portion with a front-chamber liner is reduced. The front chamber (2) has the front-chamber liner (30) fitted to an inner surface of a cylinder (10). A hydraulic chamber space communicating with the front chamber (2) and filled with hydraulic oil is formed as a cushion chamber (3) on the inner peripheral surface of a rear portion of the front-chamber liner (30). The cushion chamber (3) has a second drain circuit (from first end face grooves (46) to slits (48) to second end face grooves (47)) which is provided separately from a drain circuit that guides the hydraulic fluid passing through a liner bearing of the front-chamber liner (30) to the low-pressure circuit.