Cab Mount Rubber Layout for Low-Frequency Vibration Isolation
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Solution Overview
Problem
Conventional cab mounts fail to adequately attenuate vertical vibrations across a wide frequency range, leading to forced movement of the vehicle body due to the frame's vibrations, especially in low frequency ranges, and require complex configurations that increase manufacturing costs.
Innovation Solution
A cab mount design with vertically extending collars and spaced rubber elastic bodies that bring the rigidity and spring constant close to zero for vibrations within predetermined amplitudes, preventing vertical vibration transmission and using a middle rubber elastic body for load attenuation in other directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper-side rubber elastic body and the lower-side rubber elastic body sandwich the frame in the upper-lower direction, then the rigidity and spring constant are defined by rubber characteristics, but the transmission of vertical vibration is not sufficiently reduced in the low frequency range
Solution Approach 1:
The cab mount is divided into three separate components: an upper-side rubber elastic body, a lower-side rubber elastic body, and a middle rubber elastic body. These segmented components work together to address different frequency ranges of vibration, with the upper and lower bodies handling high frequencies and the middle body providing additional low frequency attenuation.
Solution Approach 2:
A middle rubber elastic body is introduced as an intermediary component between the upper-side and lower-side rubber elastic bodies. This middle body serves as a mediator that provides additional vibration attenuation in the low frequency range, bridging the gap between the high-frequency attenuation capabilities of the outer rubber bodies.
2Reliability
If a liquid sealed mount is adopted to optimize vibration transmission characteristics, then fine tuning capability is achieved, but manufacturing costs increase due to complicated configuration
Solution Approach 1:
The invention optimizes vibration transmission characteristics by adjusting the physical parameters of three rubber elastic bodies rather than using a complex liquid sealed mount. The rigidity, spring constant, and spacing of the rubber bodies are tuned to achieve fine control over vibration attenuation across different frequency ranges, providing a cost-effective alternative to liquid-filled mounts.
3Reliability
If the rigidity and spring constant are defined by rubber characteristics in the conventional configuration, then high frequency vibration is attenuated, but low frequency vibration causes forcible movement of the body
Solution Approach 1:
The cab mount system is segmented into three rubber elastic bodies positioned at different locations and orientations. The upper-side and lower-side bodies primarily attenuate high frequency vibrations, while the middle rubber elastic body specifically targets low frequency vibrations that cause body movement, creating a multi-layered defense against different vibration frequencies.
Solution Approach 2:
The invention adds a middle rubber elastic body component in the horizontal direction between the upper-side and lower-side bodies. This dimensional addition creates a new vibration attenuation pathway that specifically addresses low frequency vibrations, complementing the vertical attenuation provided by the upper and lower bodies.
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
The design effectively prevents body movement caused by frame vibrations across all frequency ranges while maintaining a simple configuration and reducing manufacturing costs by minimizing rubber usage and ensuring load sustainability.
Implementation Method 1
a cab mount including an upper-side rubber elastic body and a lower-side rubber elastic body that are disposed so as to face each other in the upper-lower direction on the outer periphery of a vertically extending collar
Implementation Method 2
the transmission of the vertical vibration is reduced/attenuated to a certain extent in the frequency range corresponding to the rubber characteristics
Data Source
AI summary
A cab mount for attaching a frame to a body is provided to prevent a forcible movement of the body generated under the influence of vertical vibration of the frame. A first cab mount includes: a collar extending vertically; and an upper mount rubber and a lower mount rubber disposed to face in the upper-lower direction on an outer periphery of the collar. The collar is attached to a body of a vehicle by being inserted into an attachment hole of a ladder frame of the vehicle while a peripheral part of the attachment hole is positioned between the upper mount rubber and the lower mount rubber. The upper mount rubber is spaced apart from the ladder frame in the upper-lower direction by a first predetermined distance while the lower mount rubber is spaced apart from the ladder frame in the upper-lower direction by a second predetermined distance.