Vehicle Power Transmission Tolerance Ring Lubrication Groove
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Solution Overview
Problem
Existing power transmission devices in vehicles experience rattling noise due to backlash between rotary shafts, and while tolerance rings are used to mitigate this, they suffer from durability issues due to repeated sliding and potential rigidity loss when special processing is applied for lubrication.
Innovation Solution
A power transmission device design featuring a tolerance ring with an annular portion and protrusions, where a groove on one of the rotary shafts supplies lubricant to the tolerance ring, preventing abrasion and durability degradation without requiring special processing, and additional features like notches for lubricant discharge and misalignment tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a tolerance ring is provided between the rotor shaft and the input shaft to suppress rattling noise, then rattling noise is reduced, but the tolerance ring repeatedly slides due to torque fluctuation causing abrasion and durability degradation
Solution Approach 1:
A lubricant is introduced as an intermediary substance between the tolerance ring and the rotary shaft to reduce direct metal-to-metal contact. The lubricant film prevents abrasion during repeated sliding caused by torque fluctuation, thereby maintaining durability while the tolerance ring continues to suppress rattling noise by eliminating backlash.
Solution Approach 2:
The friction characteristics of the interface between the tolerance ring and rotary shaft are changed by introducing a lubricant. This parameter change reduces the coefficient of friction, allowing the tolerance ring to slide smoothly during torque fluctuation without suffering from abrasion and durability degradation.
2Reliability
If processing is performed to form an oil supply hole in the tolerance ring to increase lubricity, then abrasion is reduced, but rigidity of the tolerance ring is compromised
Solution Approach 1:
Instead of modifying the tolerance ring structure by drilling oil holes (which would compromise rigidity), the lubricant supply path is extracted and relocated to the rotary shaft. The groove is formed in the rotary shaft to guide lubricant to the contact surface of the tolerance ring, maintaining the ring's structural integrity while still providing necessary lubrication.
3Reliability
If the tolerance ring is made larger to improve lubrication coverage, then abrasion resistance increases, but device complexity and space requirements increase
Solution Approach 1:
Lubrication is provided in advance through the groove structure in the rotary shaft, which guides and distributes lubricant to the contact surface of the tolerance ring before significant abrasion can occur. This preliminary lubrication action ensures consistent protection without requiring an enlarged tolerance ring or complex lubrication delivery mechanisms.
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 suppresses rattling noise and maintains tolerance ring durability by ensuring consistent lubrication across the circumference, preventing abrasion and misalignment issues, thus enhancing the device's operational reliability.
Implementation Method 1
The groove is configured to supply a lubricant to a region of the tolerance ring where the annular portion comes into contact
Data Source
AI summary
A tolerance ring is interposed between an output side rotary shaft and a rotor shaft. For this reason, even in a case where a backlash formed in a spline fitting portion between the output side rotary shaft and the rotor shaft is not eliminated, the rotary shafts of both of the output side rotary shaft and the rotor shaft are held by the tolerance ring without a backlash, and rattling noise can be suppressed. An oil supply groove for supplying a lubricant between an annular portion of the tolerance ring and the output side rotary shaft is provided inside an annular groove formed in the output side rotary shaft. With this, it is possible to suppress degradation of the durability of the tolerance ring without performing special processing on the tolerance ring.