Hydraulic Parking Brake Piston Rod Rotation Locking
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Solution Overview
Problem
Existing hydraulic disc brake systems with parking brakes do not effectively immobilize the piston rod in rotation relative to the housing, limiting the locking wheel's ability to immobilize the piston rod unless it is in its extreme rear axial position.
Innovation Solution
The piston rod features a rotation-blocking section that extends through a central hole in a transverse stop plate with a complementary fluted profile, and a non-reversible mechanical transmission drives the locking wheel, allowing it to be immobilized in rotation when the electric motor's output shaft is not rotated, with a secondary hydraulic cavity and piston providing additional axial thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the transverse stop plate is made in one piece with the intermediate tubular body, then the manufacturing is simplified, but the piston rod cannot be effectively immobilized in rotation relative to the housing unless the locking wheel is in its extreme rear axial position
Solution Approach 1:
The transverse stop plate is segmented into two parts: a transverse plate portion and a tubular body portion, which are assembled together rather than made in one piece. This segmentation allows the transverse plate to provide rotation blocking functionality through its central hole with non-revolution profile, while the tubular body provides structural support, resolving the contradiction between manufacturing simplicity and rotation immobilization reliability.
Solution Approach 2:
The transverse plate acts as an intermediary component between the piston rod and the housing. Its central hole with non-revolution profile serves as a mediator to block rotation of the piston rod, enabling the locking wheel to immobilize the piston rod in rotation at any axial position, not just at the extreme rear position.
2Ease of operation
If the locking wheel is used to immobilize the piston rod in rotation, then the parking brake function is achieved, but the piston rod must be in its extreme rear axial position in abutment against the transverse abutment plate
Solution Approach 1:
The central hole of the transverse plate has a non-revolution (asymmetric) profile that is complementary to the piston rod's external profile. This asymmetric geometry provides rotation blocking functionality, allowing the locking wheel to immobilize the piston rod in rotation without requiring the piston rod to be in its extreme rear axial position, thus improving ease of operation while reducing position constraints.
3Device complexity
If the piston rod is not immobilized in rotation, then the design is simpler, but the parking brake cannot effectively lock the piston rod unless in extreme rear position
Solution Approach 1:
The solution adds rotation blocking functionality in the rotational dimension by providing a central hole with non-revolution profile in the transverse plate. This allows the piston rod to be immobilized in rotation independently of its axial position, enhancing parking brake locking reliability without significantly increasing design complexity, as the rotation blocking is achieved through the geometric profile of existing components.
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
This design ensures the piston rod is securely immobilized in rotation, enabling effective operation of the parking brake without requiring the piston rod to be in its extreme rear position, enhancing the brake's functionality and reliability.
Implementation Method 1
a primary hydraulic cavity (24P) open towards the front axially and which is delimited axially towards the rear by a transverse bottom wall (26)
Implementation Method 2
a secondary hydraulic cavity (24S) open towards the front axially and which is delimited axially towards the rear by a transverse bottom wall (80) of the cover (74) and in which is mounted to slide axially a secondary piston (82) in which it thus delimits a secondary hydraulic chamber (SHC)
Implementation Method 3
a blocking wheel (140) which is screwed, reversibly, on the threaded section (124) of the piston rod (120) so as to be movable axially with respect to the piston rod, rearward by screwing or forward by passage; a controlled electric motor (166) capable of driving the blocking wheel (140) in rotation
Implementation Method 4
the blocking wheel (140) is able to be driven in rotation, in the two-way, by the electric motor (166) via a mechanical transmission which comprises a driving screw (176) which cooperates, in a non-reversible manner, with a toothed periphery (144) of the blocking wheel (140)
Implementation Method 5
the piston rod (120) comprises a section (126) for blocking the rotation of the piston rod (120) which extends axially through a central hole (112) in the transverse stop plate (100) which has an external profile which is not of revolution and which is of complementary shape to an internal profile of the central hole (112)
Implementation Method 6
a piston rod (120) which comprises a threaded section (124); a blocking wheel (140) which is screwed, reversibly, on the threaded section (124) of the piston rod (120)
Data Source
Figure 1~2
Figure 3
Figure 4~7
AI summary
The invention relates to a hydraulic control disk brake comprising a hydraulic actuation parking brake, which comprises a caliper (12), a main piston (16), a piston rod (120), a wheel (140) for locking the piston rod (120), and a transverse axial abutment plate (100) that is axially stationary and comprises a front transverse abutment surface (116). Said disk brake is characterized in that the piston rod (120) comprises a section (126) for rotationally locking the piston rod (120) that axially extends through a central hole (112) of the transverse abutment plate (100).