01.Double-acting piston hydraulic cylinder

As shown in the figure below, the hydraulic cylinder consists of a piston head 2, piston rod 3, cylinder body 4, left and right end caps 1 and 5, guide sleeve 6, and tie rods 9. The left and right end caps 1 and 5 are secured to the cylinder body 4 by four tie rods 9. A buffer system consisting of a check valve 7 and a throttle valve 8 is installed on each end cap to ensure accurate piston positioning at the end of its stroke and prevent impact. When the piston retracts, the buffer pin 10 on the piston head engages the hole in the end cap 1. At this point, the oil in the piston cavity must pass through the throttle valve 8 to be discharged. This throttling action creates an oil discharge resistance within the piston cavity, cushioning the piston. The appropriate oil discharge resistance can be achieved by adjusting the throttle valve opening. When the piston reverses its motion, high-pressure oil enters the piston cavity through the check valve 7.

02.Rack hydraulic cylinder

As shown in the figure below, the hydraulic cylinder rotates gear 5 through the reciprocating motion of piston 3, which is driven by the rack on piston 3. Cushioning of the hydraulic cylinder is achieved by fixed orifices in end caps 1 and 4. Geared hydraulic cylinders can transmit high torque, but their positioning is less accurate, so they are often used in rotating mechanisms with high loads.

03. Hydraulic cylinder with piston stroke adjustment device

As shown in the figure below, the position of positioning card 5 on piston rod 7 can be pre-adjusted according to operational needs. When hydraulic oil enters the right chamber of the hydraulic cylinder through oil port 6, piston 1 moves leftward, and the hydraulic oil in the left chamber of the hydraulic cylinder is discharged from oil port 3 via oil pipe 2. When positioning card 5 reaches the pre-adjusted position as the piston moves leftward, it pushes positioning valve 4 to close the oil discharge passage, stopping the piston and returning it to the desired operating position. When hydraulic oil enters through oil port 3, it pushes open positioning valve 4, enters the left chamber of the hydraulic cylinder through oil pipe 2, pushes the piston rightward, and the hydraulic oil in the right chamber of the hydraulic cylinder is discharged from oil port 6.

04. Hydraulic cylinder equipped with a guide device

As shown in the figure below, a guide sleeve 4 is mounted on the outer wall of cylinder body 1, while a guide rod 3 is attached to the extension of piston rod 2. As the piston moves, the guide serves several functions:

Increasing rigidity

Reducing vibration during high-speed operation

Reducing wear caused by piston rod bending.

05.Multi-position hydraulic cylinder

As shown in the figure below, hydraulic oil enters the two chambers of hydraulic cylinder 1 through two throttle valves 3. Cylinder body 1 has several holes, each connected to a two-position, two-way solenoid valve 4 that leads to the oil tank. When either solenoid valve operates to discharge oil from the oil port, the hydraulic cylinder creates an oil discharge chamber. Because of the action of throttle valve 3, when one chamber is depressurized, the other chamber maintains a certain pressure. Under this pressure, piston 2 moves toward the pressure relief chamber until it blocks the pressure relief port, and the pressure in the two chambers equalizes, causing the piston to remain in the selected position.

06. Stepper hydraulic cylinder

The figure below shows a single- and two-stage stepper hydraulic cylinder. The front-stage piston 1 also serves as the cylinder body for the rear-stage piston 2, nested within each other. The housing 3 has two high-pressure oil inlet ports, a or 6, and one low-pressure oil inlet port, c. When no high-pressure oil flows into ports a or b, low-pressure oil enters port c through pressure-reducing valve 6, pushing the piston to the right (i.e., zero position). If either control valve A or valve B operates, oil flows into port a or b, causing the piston to move left. As pressure in the left chamber of the hydraulic cylinder rises, pressure-reducing valve 6 closes, and check valve 5 opens, draining the oil from the left chamber back to the tank. When the pressure in the left chamber drops to the pressure set by the pressure-reducing valve, pressure-reducing valve 6 activates, closing the check valve, and locking the piston in its designated position. When oil flows into port a and returns to port 6, the piston moves one unit of travel, L, to the left. If oil flows into port b and returns to port a, the piston moves 2L to the left. If oil flows into both ports a and b, the piston moves 3L to the left.

07. Telescopic hydraulic cylinder

As shown in the figure below, a telescopic hydraulic cylinder is actually a multi-stage hydraulic cylinder, consisting of an internal piston rod 3, an internal hydraulic cylinder 2, and an external cylinder body 1. When hydraulic oil enters the left chamber of cylinder body 1, it first pushes the internal hydraulic cylinder 2 and piston rod 3 to the left. When the internal hydraulic cylinder 2 contacts the left end 4, the hydraulic oil pushes the piston rod 3 to continue moving until the piston rod hits the external stop. When the hydraulic oil enters the left chamber of cylinder body 1, both the internal hydraulic cylinder 2 and piston rod 3 move to the right and reset. This type of hydraulic cylinder is characterized by a long stroke and a small size when retracted. It is suitable for applications where space for the hydraulic cylinder is limited but a long stroke is required. It is commonly used in construction machinery and transport machinery.

Contact: Nancy Zhu, Sales manager, JW GROUP.

Email: nancy@jwgroup.cc

Web: https://jwcylinder.com

Mobile/Whatsapp:+86 15902166721

HYDRAULIC CYLINDER and CNC parts specialist

JW GROUP is an integrated steel product group, products include: hydraulic cylinder, hydraulic cylinder spare parts, drilling forging parts, pneumatic actuator-scotch yoke, CNC machinery parts etc.