Axial Piston Motors
In axial piston motors, the pistons move back and forth parallel to the axis of the cylinder block. These motors come in both fixed and variable displacement types. Torque is generated by the pressure acting on the ends of the pistons as they reciprocate within the cylinder block. The inline design, where the motor, drive shaft, and cylinder block are aligned on the same axis, is illustrated. Here, pressure applied to the piston ends creates a force against an angled swash plate, resulting in the rotation of the cylinder block. The generated torque is proportional to both the piston area and the angle of the swash plate. The inline piston motor can be configured as either a fixed or variable displacement unit, with the swash plate determining the volumetric displacement.
In Automotive Lift Repair Orlando variable displacement units, the swash plate is mounted on a swinging yoke, allowing its angle to be adjusted via a lever, hand wheel, or servo control. Increasing the angle enhances the cylinder displacement and torque capacity but reduces the speed of the drive shaft. Conversely, decreasing the angle increases the drive shaft speed while reducing torque capability.
Bent-Axis Piston Motors
Automotive Lift Repair Orlando Bent-axis piston motors develop torque through pressure acting on the reciprocating pistons. In this design, the cylinder block and drive shaft are oriented at an angle to one another, which exerts force on the drive shaft flange. The speed and torque depend on this angle; a larger angle results in greater displacement and torque but lower speed. The angle typically ranges from a minimum of 7.5 degrees to a maximum of 30 degrees. Bent-axis motors are available in both fixed and variable displacement types.
Radial Piston Motors
Automotive Lift Repair Orlando Radial piston motors feature pistons that move radially, or perpendicular to the axis of the output shaft. These motors operate on a principle where low speed is combined with high torque, making them suitable for a variety of power transfer applications.
Semi-Rotary Actuators
Semi-rotary actuators convert fluid energy into torque that enables rotation through a design-limited angle. Most designs allow for a rotation of up to 360 degrees, although some piston-operated actuators can exceed this limitation.
Vane-Type Semi-Rotary Actuator (Single Vane)
A single-vane rotary actuator allows only partial rotation. It consists of a vane connected to an output shaft. When hydraulic pressure is applied to one side of the vane, it rotates, but a stop mechanism prevents continuous rotation. The rotation angle for a single-vane actuator is typically 315 degrees.
Two-Vane-Type Semi-Rotary Actuator
An Automotive Lift Repair Orlando two-vane rotary actuator has the advantage of increased torque output due to the larger pressure-exposed area. However, its rotation is limited to 100 degrees, which is less than that of single-vane models. Passageways connect the various chambers of the rotary actuator.
Example 1.1: A single-vane rotary actuator has the following specifications:
– Outer radius of vane = 1.5 cm
– Width of vane = 1 cm
In this design, an endless chain and sprocket mechanism are utilized, making it suitable for multi-revolution applications. The chain is anchored to two pistons, one larger and one smaller, which separate the actuator into two halves. The larger cylinder functions as the power cylinder, while the smaller one serves as the chain return or seal cylinder. An idler maintains constant tension on the chain. When pressure is applied to one port of the actuator, the larger piston moves away from the port due to the differential areas of the two pistons. This movement pulls the chain, causing the sprocket and output shaft to rotate.
Automotive Lift Repair Orlando Rack and Pinion Rotary Actuator
A rack and pinion rotary actuator is a widely used design for achieving partial revolution actuation. It comprises a hydraulic cylinder integrated with a rack and pinion gear mechanism. The rack gear, located on the piston rod, engages the pinion gear, converting the linear motion of the piston into rotary motion, which is then transmitted to the load via the output shaft.
Another variation of the rack and pinion semi-rotary actuator features a design where the cylinder drives a pinion gear, and the rack is an integral component of the piston rod. The rotation angle is determined by the cylinder’s stroke, the rack’s dimensions, and the pitch circle diameter of the pinion. The beginning and end of the stroke can be adjusted using an internal stop, also known as a stroke adjuster.
An Automotive Lift Repair Orlando hydraulic motor is a mechanical actuator that transforms hydraulic pressure and flow into torque and angular displacement (rotation). It serves as the rotary equivalent of a hydraulic cylinder and is typically designed to handle working pressure on both sides.
Gear motors are commonly used in simple rotating systems and offer several advantages, including low initial cost, high RPM capabilities, greater tolerance to contamination, and durability. Failures in gear motors are generally less catastrophic compared to other types of hydraulic motors.
A hydraulic gear motor consists of two gears: the driven gear, which is connected to the output shaft via a key, and the idler gear. High-pressure oil enters one side of the gears, flowing around their periphery, between the gear tips and the housing wall, before exiting through the outlet port. The gears mesh together, preventing oil from flowing back to the inlet side. For lubrication, the gear motor utilizes a small amount of oil from the pressurized side, which is bled through typically hydrodynamic bearings and then vented either to the low-pressure side of the gears or through a dedicated drain port in the motor housing.
A significant advantage of Automotive Lift Repair Orlando gear motors is that catastrophic failures are much less frequent than in many other types of hydraulic motors. This is due to the gradual wear of the housing and/or main bushings, which leads to a slow decline in the motor’s volumetric efficiency rather than an immediate breakdown. As a result, a gear motor may degrade to the point of near uselessness long before wear causes it to seize or fail entirely.
The Ultimate Guide to Hydraulic Motors