Hydraulic Gear Pump Axial Compensation for Zero Flow
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Solution Overview
Problem
Current hydraulic transmissions and pumps with continuously variable flow or rotational speed face issues such as leakage, incompressibility of hydraulic fluid, and inability to operate at zero flow rate or rotational speed, limiting their applicability in industrial and commercial use.
Innovation Solution
A hydraulic transmission system with at least one gear pump or hydraulic gear motor featuring rotors with axial clearance and surface compensation systems, allowing for continuous variation of flow or rotational speed from zero, using sliding sealings and compensation cylinders to manage volume changes and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rotors are designed with axial sliding capability to enable continuous flow rate variation, then the pump can achieve continuously variable flow rate, but leakage occurs due to gaps between teeth and rotors
Solution Approach 1:
A compensating rotor is introduced as an intermediary component between the driving rotor and the housing. This compensating rotor carries flow passages that align with the tooth spaces of the driving rotor, creating a sealed pathway for hydraulic fluid. The intermediary rotor prevents direct leakage paths while allowing the axial sliding motion necessary for continuous flow rate variation.
Solution Approach 2:
The patent employs a nested structure where the compensating rotor is positioned within the housing and interacts with the driving rotor. The flow passages in the compensating rotor are nested within the tooth spaces of the driving rotor, creating a hierarchical sealing system that maintains reliability while enabling continuous operation from zero flow rate.
2Productivity
If rotors slide axially to change inner volume and achieve zero flow rate, then continuous operation from zero is possible, but volume changes in closed gaps between teeth cause operational issues
Solution Approach 1:
The compensating rotor acts as a mediator that provides a controlled pathway for hydraulic fluid during axial sliding. As the driving rotor slides axially to change inner volume, the compensating rotor's flow passages ensure that volume changes in closed gaps are compensated by fluid flow through the nested passages, preventing operational problems while enabling zero flow rate operation.
Solution Approach 2:
The patent utilizes parameter changes in the axial position of the driving rotor to achieve continuous flow rate variation from zero. The compensating rotor's flow passages are designed to adapt to these parameter changes, maintaining proper fluid flow paths and volume compensation throughout the entire range of motion, including at zero flow rate positions.
3Loss of energy
If rotors are made incompressible to maintain hydraulic efficiency, then energy transfer is efficient, but relative axial movement becomes impossible
Solution Approach 1:
The compensating rotor serves as a mediator that reconciles the contradiction between incompressibility and axial movement. By providing nested flow passages, it allows the hydraulic fluid to be compressed or expanded in a controlled manner during axial sliding, maintaining hydraulic efficiency while enabling the necessary movement for continuous flow rate variation.
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
Enables continuous, efficient operation from zero output speed with variable torque or flow, enhancing the functionality and applicability of hydraulic systems in various industrial and commercial applications.
Implementation Method 1
the sliding sealing with the compensation cylinders have a diameter corresponding to an outer diameter of the gear apices of the inner rotor with outer teeth; and it contains at least one surface compensation system for compensation of inner volume changes that arise at relatively axial movement of the rotors
Implementation Method 2
a hydraulic transmission system with at least one gear pump or hydraulic gear motor featuring rotors with axial clearance and surface compensation systems
Implementation Method 3
allowing for continuous variation of flow or rotational speed from zero, using sliding sealings and compensation cylinders to manage volume changes and prevent leakage
Data Source
Figure 1~3a
Figure 4~11b
Figure 9~9d
AI summary
Gearbox (1) with continuously variable parameters comprises at least one pump (2) and at least one hydraulic motor (3), wherein at least one pump (2), or a hydraulic motor (3) is with the continuously variable parameters. It consists of an input shaft (4) and one or more output shafts (5), (6) with equal or proportional continuously variable regulation of revolutions. It may be constructed as a centralized - one piece, or de-centralized, where the pump (2) is at a distance from the hydraulic motor (3) and the liquid medium passes through the hydraulic pipes (19) and (20). Pump (2) and the hydraulic motor (3) may be of the same design or different and are provided with the shift mechanism composed of a holder (13), the shift wheel (14) and the snap lock (15). Gear pump (2) with a continuously variable flow rate comprises at least one shaft (4) which holds the inner rotor (8) that is inserted into the outer rotor (7). The rotors (7),(8) are mutually axially movable. The inner rotor (8) is provided from the both sides with a sliding seal (9) with the shift screw and sliding seal (10) with compensatory cylinders are secured by snap locks (15). These parts are fitted into the central body (18), side seal (12) and side seal (11) having inlet opening (21) and outlet opening (22) connected by bypass regulated member. Compensating pistons (23) of the planar compensating system are rigidly attached to the side seal (11). Pump (2) with the continuously variable flow rate comprises at least one planar compensating system.