Hydrostatic Transaxle Filter Exchange Mechanism
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Solution Overview
Problem
Conventional hydrostatic transaxles face difficulties in oil filter exchange due to the charge pump falling off when the lid is removed, requiring reassembly and compression of a spring, and the setting pressure changing with bolt tightness, making filter replacement cumbersome.
Innovation Solution
A hydrostatic transaxle design featuring a casing with an openable and closable filter insertion port, a filter holding member with a support base and filter connection port, and a floating type charge pump, allowing easy filter exchange and maintaining oil tightness with an energizing spring between the filter cap and body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lid for attachment and detachment of the filter is removed, then the filter can be accessed, but the charge pump falls off by its own weight requiring reassembly
Solution Approach 1:
The device is segmented into modular components: the filter holder assembly is separated from the charge pump assembly. The filter holder can be independently removed through the filter insertion port without affecting the charge pump, which remains secured to the center section. This segmentation eliminates the need to disassemble or reassemble the charge pump during filter exchange operations.
Solution Approach 2:
The filter holder is extracted as a separate removable component from the main housing. It can be taken out through the filter insertion port independently, while the charge pump remains in place attached to the center section. This extraction design allows filter maintenance without disturbing the charge pump assembly.
2Reliability
If the lid is closed while compressing the spring, then the charge pump is secured, but filter exchange becomes difficult
Solution Approach 1:
The filter holder is designed as a separate module that can be removed independently of the charge pump securing mechanism. The lid closes to secure the charge pump while leaving the filter insertion port accessible for filter holder removal and reinstallation, enabling easy filter exchange without compromising charge pump reliability.
Solution Approach 2:
The filter holder is pre-positioned with the filter element before insertion into the housing. The energizing spring is pre-compressed during assembly to ensure proper seating. During maintenance, the filter holder can be quickly removed and reinserted without requiring manual spring compression, as the spring automatically energizes upon insertion.
3Reliability
If the setting pressure of the charge pump changes depending on bolt tightness, then the pump can be secured, but consistent pressure settings cannot be maintained
Solution Approach 1:
The charge pump is segmented into a modular assembly with the center section that includes integrated mounting features. The pump is secured using standardized fastening mechanisms with controlled torque specifications, ensuring consistent pressure settings. The segmentation allows the pump to be pre-assembled and tested before installation, maintaining pressure setting consistency.
Solution Approach 2:
The charge pump setting pressure is determined by the pre-compression of the energizing spring rather than by bolt tightness variability. The spring compression force is controlled during assembly to provide consistent pressure settings. This parameter change from bolt-dependent pressure to spring-dependent pressure eliminates variability in pressure settings.
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
Facilitates easy and efficient oil filter exchange without the need for reassembling the charge pump, ensuring consistent pressure settings and simplifying maintenance processes.
Implementation Method 1
an energizing member that energizes the filter body to the filter connection port side
Implementation Method 2
the support base is a hollow cylindrical portion and oil-tightly partitions an inside of a cylinder and an outside of the cylinder
Data Source
AI summary
A hydrostatic transaxle includes: a casing that is provided with an openable and closable filter insertion port and is filled with hydraulic oil; a hydraulic continuously variable transmission that is arranged inside the casing; a filter holding member that includes a support base that is a hollow cylindrical portion and oil-tightly partitions an inside of a cylinder and an outside of the cylinder, and a filter connection port that is a hollow cylindrical portion extending from a peripheral side surface of the support base and communicating with the inside of the cylinder, the support base communicating the inside of the cylinder to the port, and arranged between the center section and the casing facing the port; and a filter body that is freely inserted to and removed from the casing via the filter insertion port.