Structural Features of Output Shaft Force-Balanced Multi-Input Gear Motor

Three small gears form three internal motors in conjunction with the crescent plate, common gears, and front and rear side plates. Simultaneously, three common gears form three external motors with the central large gear, housing, and front and rear side plates. A key design efficiency is that the front and rear side plates serve as common components for both internal and external motors, reducing part count and complexity compared to separate motor assemblies.

The three common gears are distributed at 120° intervals, creating a symmetric configuration that enhances balance and reduces vibration. This geometric arrangement is critical to the motor's performance characteristics, much like the precision gear alignment in a high-quality gear hydraulic pump. While theoretically, the number of common gears and small gears need not be limited to three—with possibilities for more than three or as few as two—practical engineering considerations have demonstrated that three provides the optimal balance of performance, complexity, and manufacturing practicality.

This gear arrangement represents a sophisticated evolution of basic gear mechanics, taking the fundamental principles that make the gear hydraulic pump effective and adapting them for motor applications with enhanced functionality. The inclusion of the crescent plate is particularly noteworthy, as it manages fluid flow between gear sets with greater precision than found in many conventional gear hydraulic pump designs, contributing to the motor's overall efficiency and performance characteristics.

A distinguishing feature of this motor design is the presence of a port plate and a port disc on each side of the motor. This dual porting system represents a significant advancement over the more simplified fluid control found in a basic gear hydraulic pump, enabling the sophisticated operation of the multi-input configuration.

Each port plate features oil passages on both faces—one side containing inlet passages and the opposite side containing outlet passages. This clever design allows each port plate to manage fluid flow in multiple directions depending on operational requirements. The port discs work in conjunction with the port plates to control oil distribution to either the internal motors or external motors, with one side's port plate and disc assembly dedicated to the internal motors and the opposite side's assembly dedicated to the external motors.

The independent porting systems are crucial to the motor's versatility, as they enable completely separate operation of the internal and external motor groups. This separation is achieved through precise machining of the flow passages and careful alignment of the porting components, ensuring minimal cross-talk between the two systems. The level of precision required in these components exceeds that of a standard gear hydraulic pump, as the multi-input motor must maintain separation between multiple fluid circuits operating at potentially different pressures and flow rates.

This sophisticated porting design allows for true independent operation of the motor groups, rather than simply providing parallel flow paths. Each system can be controlled independently, with its own pressure and flow characteristics, making the motor capable of complex performance profiles that would be impossible with a conventional gear hydraulic pump or single-input hydraulic motor. The porting system's design ensures efficient fluid delivery with minimal pressure losses, contributing to the motor's overall efficiency and performance capabilities.

The three common gears are strategically positioned at 120° intervals around the central large gear, creating a symmetric configuration that forms the basis for the motor's exceptional radial force balance. This balanced design addresses one of the primary performance limitations of many conventional hydraulic motors and even some gear hydraulic pump designs, where unbalanced radial forces can lead to increased wear, vibration, and reduced efficiency.

On the large gear, three oil suction ports and three pressure oil ports are alternately and uniformly distributed around the circumference. This alternating pattern ensures that hydraulic forces act on the gear from all directions in a balanced manner. As the gear rotates, the pressure forces are continuously distributed symmetrically, preventing the development of net radial loads that would otherwise push the gear shaft against its bearings.

The practical benefits of this balanced design are substantial. By eliminating net radial forces on the output shaft, bearing loads are significantly reduced, extending bearing life and reducing maintenance requirements. Vibration and noise are minimized due to the smooth, balanced operation, making the motor suitable for applications where quiet operation is important. Additionally, the elimination of radial deflection under load maintains optimal gear meshing and clearances, preserving efficiency even under varying load conditions.

This radial force balancing represents a sophisticated engineering solution that sets this motor apart from many conventional designs. While some high-end gear hydraulic pump models incorporate similar balancing principles, the multi-input configuration of this motor makes the balanced design particularly critical to its performance. The 120° distribution ensures that balance is maintained throughout the entire rotation cycle, with no positional variations in force distribution. This level of refinement contributes significantly to the motor's overall efficiency, durability, and smooth operation across its full range of performance parameters.