Swivel Joint Angle Sensing Through the Pilot Oil Passage
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Solution Overview
Problem
Existing swivel joint designs for working machines require complex installations and additional space for swivel angle detection, leading to increased size and difficulty in retrofitting detection instruments on machines not originally designed for them.
Innovation Solution
A swivel joint design that incorporates a pilot oil passage for a rod with a rotation angle sensor, allowing for easy installation and minimizing size increase, using a noncontact sensor to detect the swivel angle without requiring additional space, and utilizing a seal member to manage oil distribution and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation detector is mounted on the side of the rotor or housing to detect swivel angle, then the swivel angle can be detected, but the size of the swivel joint is increased and the structure becomes more complex
Solution Approach 1:
The rotation detector is integrated into the existing swivel joint structure by utilizing the pilot oil passage. The detector is mounted on the inner body that rotates together with the rotor, and the detection rod extends through the pilot oil passage, merging the detection function with the existing hydraulic structure without adding external components that would increase overall size
Solution Approach 2:
The pilot oil passage serves dual purposes: it continues to distribute pilot oil for hydraulic control while simultaneously serving as a mounting path for the detection rod of the rotation detector. This multi-functional use of existing space eliminates the need for separate detection structure space
2Measurement precision
If a detection surface is provided on the outer peripheral surface of the rotor with a rolling roller depressed against it, then the swivel angle can be detected, but the installation becomes complicated and time-consuming
Solution Approach 1:
The complex detection surface and rolling roller mechanism is replaced by extracting only the essential detection function. A simple rod extends through the pilot oil passage to directly indicate rotation angle, eliminating the need for complicated mechanical contact surfaces and rollers while maintaining detection capability
Solution Approach 2:
The mechanical rolling roller contact detection system is replaced with a simpler rod-based detection mechanism that utilizes the existing pilot oil passage space. The rod's position directly reflects the rotation angle without requiring complex mechanical interactions, simplifying both manufacturing and installation
3Measurement precision
If the swivel joint structure is significantly different from the conventional structure to accommodate the measurement instrument, then the measurement can be implemented, but it becomes difficult to retrofit on existing swivel joints
Solution Approach 1:
The detection rod is installed within the existing pilot oil passage, which is a standard feature in conventional swivel joints. This approach allows the detection system to be retrofitted on existing swivel joints without requiring significant structural modifications, as the pilot oil passage already provides the necessary mounting space
Solution Approach 2:
The detection rod is nested within the existing pilot oil passage structure, utilizing the hollow space already present in the inner body. This nesting approach allows the detection function to be added without altering the external dimensions or basic structure of the swivel joint, enabling easy retrofitting
Data Source
AI summary
An embodiment of this invention provides a swivel joint for a working machine that makes it easy to install a device for detecting rotation angle and is able to suppress the increase of the size due to the installation of the device. An embodiment of the present invention includes the swivel joint that includes an outer body being secured on one of the lower traveling body and the upper swiveling body and having a blocking surface on one end; an inner body being secured on another of the lower traveling body and the upper swiveling body and being relatively and rotatably fitted in the outer body while opposing to the blocking surface at one end n in the manner of making a space; a pilot oil passage being formed on rotational center line CL of the inner body for distributing pilot oil; a rod being inserted into the pilot oil passage and being secured on one of the outer body and the inner body; and a rotation angle sensor being secured on the other end of the outer body and the inner body for detecting a rotation angle of the rod.