Hydraulic Control Device Pulsation Absorption Valve Assembly
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Solution Overview
Problem
Conventional hydraulic control devices for working vehicles, such as wheel loaders, have complex communication lines between the boom cylinder and accumulator, making assembly difficult and hindering downsizing and space-saving designs.
Innovation Solution
A hydraulic control device with a directional control valve and pulsation absorption control valve arranged in a center bypass line, allowing for simplified communication line construction, reduced pressure losses, and space-saving design, while also enabling hydraulic load generation for exhaust gas purifying device regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple hydraulic pipes are used to connect the boom cylinder and accumulator, then the communication line can be established, but the construction becomes complicated and assembly operability deteriorates
Solution Approach 1:
The patent merges multiple hydraulic pipes into a single integrated communication line that branches from the main line between the directional control valve and the pulsation absorption control valve. This consolidation simplifies the construction while maintaining reliable connection between the boom cylinder and accumulator, directly resolving the contradiction between connection reliability and assembly operability.
2Reliability
If multiple hydraulic pipes are used for communication line, then connection can be established, but device size increases and space saving is hindered
Solution Approach 1:
Multiple hydraulic pipes are merged into a single communication line with proper branching, reducing the overall volume occupied by the hydraulic system while maintaining all necessary connections. This directly addresses the contradiction between connection reliability and device downsizing.
3Reliability
If communication line is lengthened to connect hydraulic actuator and accumulator, then connection can be established, but pressure losses increase
Solution Approach 1:
The communication line is strategically branched from the main line at an optimal position between the directional control valve and the pulsation absorption control valve. This preliminary positioning minimizes the length of the communication line while ensuring proper connection, thereby reducing pressure losses and maintaining connection reliability.
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
Improves operability during assembly, reduces pressure losses, achieves downsizing and space-saving in the device, and enhances the reliability of the exhaust gas purifying device by effectively regenerating filters even under low engine load conditions.
Implementation Method 1
an accumulator connected via one communication line branched from one main line out of the pair of the main lines to the hydraulic actuator to absorb pressure pulsations generated in the hydraulic actuator
Implementation Method 2
a directional control valve for controlling switching of the pressurized oil to be supplied to the hydraulic actuator from the hydraulic pump
Implementation Method 3
a hydraulic pump constituting a hydraulic source for the working vehicle together with a tank; at least one or more hydraulic actuators driven by pressurized oil discharged from the hydraulic pump
Data Source
Figure 1
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Figure 3
AI summary
A boom control valve (29) and a pulsation absorption control valve (33) are provided in the halfway point of a center bypass line (21). The pulsation absorption control valve (33) is arranged in a position downstream of the boom control valve (29). The pulsation absorption control valve (33) is switched to a blockade position (d) and a communication position (e) by a pilot pressure from a remote control valve (51). The pulsation absorption control valve (33) is constituted such that one main line (32A) out of a pair of main lines (32A), (32B) is communicated with or blocked off from an accumulator (38) via one communication line (36A) and the other main line (32B) is communicated with or blocked off from the side of a tank (11) via the other communication line (36B). The accumulator (38) is operated as a dynamic damper at the traveling of a vehicle. This arrangement enables the construction of the communication line (36A) to be simplified, thus improving operability at assembling.