EPB Motor Transmission Unit With Non-Rotating Push Rod Sealing
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Solution Overview
Problem
Conventional motor transmission units for electronic parking brake devices experience seal ring deformation due to eccentric shaft movement, leading to brake oil leakage, as the eccentric rod shakes and swings during operation.
Innovation Solution
A motor transmission unit design featuring a case, driving member, board, rod, and push unit, where the board moves axially along the driving member without rotation, directly pushing a push unit to contact a brake disk, eliminating rotational and swinging motion that deforms the seal ring, and incorporating a seal ring mounted to the push unit to prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the eccentric shaft is driven by the transmission shaft to ensure linear movement without rotation, then the electronic parking brake function is achieved, but the eccentric shaft shakes and swings during operation causing seal ring deformation and brake oil leakage
Solution Approach 1:
The patent extracts and eliminates the eccentric shaft component that causes shaking and swinging. Instead of using an eccentric shaft mechanism, the invention employs a linear movement mechanism where the push rod moves directly along the transmission shaft without rotation, removing the source of harmful vibrations and seal ring deformation.
Solution Approach 2:
The patent introduces a push rod as an intermediary component between the transmission shaft and the brake components. This push rod transmits the driving force linearly without rotation, acting as a mediator that eliminates the shaking and swinging problems associated with eccentric shaft mechanisms while maintaining the necessary braking function.
2Stability of the object's composition
If the eccentric rod continuously contacts the recess of the push rod to prevent rotation, then linear movement is maintained, but the shaking and swinging action reduces seal ring life quickly
Solution Approach 1:
The patent removes the eccentric rod component entirely, replacing it with a push rod that moves linearly without rotation. This extraction eliminates the contact between rotating and non-rotating parts that causes shaking and swinging, thereby preventing seal ring deformation and extending seal ring lifespan.
Solution Approach 2:
Instead of preventing rotation through continuous contact between eccentric components, the invention inverts the approach by designing a system where rotation is inherently prevented through the linear movement mechanism. The push rod moves only along the transmission shaft without any rotational contact, eliminating the harmful shaking and swinging actions.
Data Source
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AI summary
A motor transmission unit for an electronic parking brake device includes a case, a driving member, a board, a rod and a push unit. The case is slidably mounted to a cap of a clamp. The driving member is partially inserted into the case. The board is threadedly mounted to the driving member. The rod is located between inner periphery of the passage and the board. The push unit has a first end thereof contacting the first end face, and a second end of the push unit is inserted in the clamp. A portion of the second end of the push unit contacts a piston. When the driving member is driven, the board moves axially. The board is restricted by the rod and does not rotate. The board pushes the push unit axially which moves the piston to push a lining plate of the clamp to contact a brake disk.