Hollow Rack Manufacturing Using Dual Push Rods for Rotation Control
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Solution Overview
Problem
Existing methods for manufacturing hollow racks for vehicle steering systems face issues such as processing failures, apparatus damage, and large apparatus size due to inadequate rotation stoppage reliability and complex die assembly structures, which complicate the separation of formed products from the upper die.
Innovation Solution
A method and apparatus that use a die assembly with a tooth die to form a hollow rack by inserting and removing metal core push rods through opposite ends, ensuring high reliability of rotation stoppage and using a shared driving portion to reduce apparatus size, and a separating mechanism to automate the removal of the formed rack from the upper die without increasing the die assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal core push rods are inserted and removed alternately through openings at both ends to press metal cores into the pipe material, then the rack corresponding to the tooth profile can be formed, but the rotation stoppage reliability is insufficient causing processing failures and apparatus damage
Solution Approach 1:
The die assembly is segmented into an upper die and a lower die with separate tooth profile portions, allowing independent control and rotation stoppage mechanisms at each end. This segmentation enables the metal core to be restrained from rotating by engagement with either the upper die or lower die during the alternating pressing process, thereby improving rotation stoppage reliability and preventing processing failures.
Solution Approach 2:
A projection on the metal core push rod engages with an oval depression on the end face of the metal core to act as an intermediary rotation stoppage mechanism. This intermediary feature prevents the metal core from rotating during pressing by providing a mechanical engagement that stops rotation, thereby eliminating processing failures and apparatus damage caused by uncontrolled rotation.
2Manufacturing precision
If a complex die assembly structure is used to hold the pipe material and form the rack, then the tooth profile can be formed, but the separation of the formed product from the upper die becomes difficult
Solution Approach 1:
The formed rack is extracted or removed from the die assembly by utilizing the space created when the upper die and lower die are separated. The metal core push rods are first removed from the pipe material, creating clearance that allows the formed rack to be easily taken out from between the upper and lower dies, thereby simplifying the product separation process while maintaining tooth profile formation precision.
Solution Approach 2:
The metal core push rods are retracted from the pipe material before attempting to remove the formed rack. This preliminary action of withdrawing the push rods creates necessary clearance and prevents interference during the subsequent removal of the formed rack from the die assembly, making the separation process easier while preserving the precision of the formed tooth profile.
3Ease of operation
If metal cores are pressed into the pipe material with rotation stoppage released, then the metal core can be inserted, but the metal core may rotate freely causing excessive load and apparatus damage
Solution Approach 1:
A rotation stoppage mechanism is implemented in advance during the metal core insertion process. The projection on the metal core push rod engages with the oval depression on the metal core end face to prevent rotation before excessive load can develop. This preliminary anti-action counteracts the potential harmful effect of free rotation, allowing easy insertion while protecting apparatus durability.
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 solution effectively prevents processing failures and apparatus damage while reducing the apparatus size and simplifying the die assembly structure, enabling reliable and efficient manufacturing of hollow racks with improved rotation control and automated product separation.
Implementation Method 1
plastically fluidizing the fabric of the processing wall portion adjoining the tooth die outward from inside of the hollow material so as to form a rack corresponding to the tooth die
Data Source
AI summary
With a first push rod which is to be inserted/removed into/from a steel pipe through an opening at one end and a second push rod which is to be inserted/removed into/from the steel pipe through an opening at the other end, a metal core disposed on a side on which the first push rod is inserted/removed into/from the die assembly is sandwiched and this metal core is stopped from rotating with the first push rod. With the state of stopping the rotation of the first push rod, the metal core is introduced into the steel pipe through the opening at the one end by both the push rods. After the metal core is pressed into the steel pipe while stopped from rotating with the first push rod, this metal core is pushed back by the second push rod.