Swash Plate Piston Pump Retainer for Phase-Synchronized Rotation
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Solution Overview
Problem
The existing liquid pressure rotary machines experience a phase delay between the retainer and the cylinder block, leading to potential damage from piston contact with the cylinder block or retainer, which affects the machine's durability and efficiency.
Innovation Solution
The design incorporates a retainer bushing with projecting portions and a retainer with groove portions, allowing for integral rotation and swinging of the retainer, thereby synchronizing the rotation phase of the retainer with the cylinder block, reducing sliding resistance and preventing abnormal piston rod tilt and contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the retainer is rotated to follow the cylinder block, then the liquid pressure rotary machine can function properly, but a phase delay occurs between the retainer and the cylinder block causing piston contact with peripheral members
Solution Approach 1:
The retainer bushing is pre-positioned on the rotation shaft with projecting portions that engage with groove portions in the retainer before operation begins. This preliminary engagement establishes a fixed rotational relationship, ensuring the retainer starts in the correct phase position and maintains synchronization throughout operation, preventing the phase delay that would otherwise cause piston contact with peripheral members.
2Loss of time
If the retainer and cylinder block are rotated integrally, then phase synchronization is maintained, but sliding resistance increases due to direct contact between reciprocating pistons and the swash plate
Solution Approach 1:
The retainer acts as an intermediary component between the cylinder block and the swash plate. It transmits rotational motion from the cylinder block while maintaining phase synchronization, but prevents direct sliding contact between the reciprocating pistons and the swash plate. This intermediary role reduces sliding resistance and energy loss while preserving the necessary rotational synchronization.
3Ease of operation
If the retainer is supported by the retainer bushing to be rotatable, then rotation is enabled, but phase delay occurs causing abnormal piston rod tilt
Solution Approach 1:
The retainer bushing features a spherical outer peripheral surface that engages with a corresponding spherical inner peripheral surface in the retainer. This spherical contact geometry allows the retainer to rotate freely while maintaining precise phase synchronization with the cylinder block. The curved surfaces ensure consistent rotational alignment, preventing abnormal piston rod tilt while preserving rotational freedom.
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 configuration reduces rotation delay, suppresses contact between pistons and peripheral members, and enhances the durability and efficiency of the liquid pressure rotary machine by maintaining phase synchronization and minimizing leakage.
Implementation Method 1
since the retainer and the swash plate are connected by the thrust bearing, it is possible to suppress sliding resistance occurring in a conventional hydraulic pump with a swash plate
Implementation Method 2
the retainer bushing includes a bushing outer peripheral surface which is formed in a spherical surface shape projected toward the radially outside in rotation of the rotation shaft, and is supported on the rotation shaft so as to be rotatable in conjunction with the rotation of the rotation shaft. The retainer includes a retainer inner peripheral surface which is formed in a recessed spherical surface shape, the retainer inner peripheral surface being slidable with respect to the bushing outer peripheral surface
Implementation Method 3
the retainer bushing has at least one projecting portion projecting from the bushing outer peripheral surface toward the radially outside, the projecting portion whose leading end portion is formed in a spherical surface shape, at least one groove portion extending along the direction in which the retainer is swung about the axis is formed on the retainer inner peripheral surface of the retainer, and by engaging the at-least-one projecting portion with the at-least-one groove portion, the retainer and the retainer bushing are integrally rotatable about the center axis
Data Source
AI summary
A liquid pressure rotary machine in which a rotation delay of a retainer with respect to a cylinder block is reduced and contact of pistons placed between the retainer and the cylinder block with peripheral members is suppressed is provided.A piston pump includes a rotation shaft, a cylinder block, piston heads, piston rods, a retainer, a swash plate, and a tilt adjustment mechanism. When the tilt adjustment mechanism swings the swash plate, a discharge amount of the piston pump becomes variable. The retainer to be rotated together with the piston heads and the piston rods is supported by a retainer bushing provided in the rotation shaft. By engaging ball pins of the retainer bushing with spherical surface pin grooves of the retainer, the retainer and the retainer bushing are integrally rotatable about the center axis of the rotation shaft and the retainer is swung about the spherical surface center.