hydraulic cylinder cross-section diagram

What is a Hydraulic Cylinder?

By Momentum |
what is a hydraulic cylinder

Whether you are simply wondering “what is a hydraulic cylinder?” or looking learn about hydraulic cylinder parts and how they work, or possibly are considering hydraulic cylinder repair or a hydraulic cylinder rebuild, understanding the basics of these cylinders is essential. 在这个液压缸的权威指南中，我们涵盖了一些关于这些sb沙巴体育投注的最常见的问题.

What Is a Hydraulic Actuator?

Hydraulic cylinders, or hydraulic actuators, are used extensively in several industries, including manufacturing, construction, civil engineering and aviation. 这些sb沙巴体育投注在各种应用中以线性运动产生机械力. They are typically used for pressing, pulling, pushing or lifting something that requires exceptional force.

如果你曾经使用过液压千斤顶来提升你的车辆或操作过叉车, you’ve used a hydraulic cylinder.

How Does a Hydraulic Actuator Work?

液压执行器是根据帕斯卡流体力学原理工作的. In the 17th century, 帕斯卡(Blaise Pascal)发现，液压流体中压力的任何变化都会导致能量在流体腔内各个方向上的均匀分布. 这意味着，如果你在一个容器里有两个活塞，对其中一个活塞施加X的压力, an equal X amount of pressure affects the second piston.

帕斯卡还发现，流体室中的压力等于施加的力除以室的面积. This formula P=F/A is the foundation for industrial machinery worldwide. 例如，流体室中的两个活塞，对第一个sb沙巴体育投注施加压力. If the area is five times greater than the first area, the force on the second cylinder is five times greater.

Hydraulic Cylinder Components

Hydraulic cylinder manufacturers can build cylinders in all sizes. 从几盎司重的微型液压缸到与挖掘铲一起使用的大型工业液压缸, hydraulic actuators generally contain the same basic components:

  • Piston活塞杆穿过sb沙巴体育投注的头部，利用液压油的力量来收缩或伸展. Seals are placed around the piston to maintain the correct pressure in the barrel.
  • Cylinder barrel: The barrel is constructed of a seamless steel tube that houses the cylinder. The barrel’s solid structure holds the pressure and prevents leaking.
  • Cylinder head: The head is the part of the cylinder where the piston retracts and extends. 当活塞伸出时，筒体的另一端关闭以保持压力. 缸盖包含轴承和密封件，使活塞对齐并保持sb沙巴体育投注密封.
  • Cylinder base筒体在sb沙巴体育投注底部封闭，密封严密，防止流体泄漏. The equipment that uses the cylinder is mounted at the base.
  • Gaskets, seals and other components液压执行器中的密封件和垫圈是动态部件，必须承受极端压力和温度而不会失效. The seals are made from different materials, including Teflon, polyurethane, fluorocarbon, metal and nitrile rubber. Some materials like rubber are suited for low-temperature operation, but for high-temperature jobs, the seals are fluorocarbon.

Hydraulic vs Pneumatic Cylinders

而液压缸使用不可压缩流体(通常是矿物油)来产生直线运动, sb沙巴体育投注依靠由压缩机或手动泵驱动的压缩空气来产生直线运动. Although both types of cylinders are used throughout the world, each type has its advantages and disadvantages.

Hydraulic Cylinder Advantages

液压缸的马力重量比优于气动缸, with hydraulics gaining one or two horsepower per pound. When it comes to power, 一个液压缸所产生的机械力是相同尺寸的气压缸的25倍.

Unlike pneumatic cylinders that max out at 250 psi, a top-of-the-line hydraulic pump can produce 4000 psi. Since the hydraulic fluid is incompressible, 液压缸不需要额外的流体来保持恒定的力和扭矩. 即使液压泵和马达位于离操作有很大距离的地方, they can function efficiently without a noticeable loss of power.

Hydraulic Cylinder Disadvantages

液压缸比气动模型更复杂，需要几个额外的组件, including release valves, pumps, motors, reservoirs and heat exchangers. 汽缸最显著的缺点之一是容易漏液. 与气动缸不同，泄漏的液压缸会污染其他部件.

Pneumatic Cylinder Advantages

Pneumatic cylinders are far less complex than hydraulics, but they’re incredibly accurate in creating linear motion. 气动执行器擅长在极端温度下工作，通常在-40°F至250°F的范围内工作. In extreme conditions, 由于气动依赖于不需要电机操作的压缩空气，因此造成的火灾危险或爆炸风险较小. 与液压缸相比，气动的购买和操作成本更低.

Pneumatic Cylinder Disadvantages

Unlike hydraulics that can be used with several applications, 除非添加阀门和调节器来修改sb沙巴体育投注，否则气动执行器是为一个任务加工的. Although compressed air is cheap and widely available, it can damage the equipment when contaminated by oil or lubricant. 气瓶效率也较低，因为即使气瓶不动，压缩机也必须不断运行.

Types of Hydraulic Cylinders

There are many types of hydraulic cylinders for sale, with these being the four most common:

Single-acting cylinders

Single acting hydraulic cylinders 当液压流体进入单个端口并流入sb沙巴体育投注并使sb沙巴体育投注缩回时产生动力. Also called push cylinders, 它们的特点是单作用活塞在一个方向上移动，需要电机或弹簧来重置其位置.

Double-acting cylinders

In double acting hydraulic cylinder models, fluid moves into one port and exits through a second port, forcing the cylinder to retract and extend. 有两个加压腔，双作用活塞不需要弹簧或电机操作.

Telescopic cylinders

在起重机等重型设备中，伸缩式sb沙巴体育投注采用一系列单作用sb沙巴体育投注. When one cylinder retracts, it transfers force to the next cylinder.

Tandem cylinders

With two separate barrels connected by the piston rods, 串联sb沙巴体育投注的设计实现了一个显着程度的力在一个小的区域. Tandem cylinders can be combined in stages to provide more power.

How To Choose a Hydraulic Actuator

After determining the application that requires a hydraulic linear actuator, you must consider several factors before selecting the ideal actuator. 规划和设计过程对于高效的水力作业至关重要, and the primary elements in the process include:

  • Calculating Mass: 被液压系统提起的物体的质量影响着圆柱体的尺寸和耐久性.
  • Determining the physics involved: 简单的按压操作是否需要液压系统，还是需要更复杂的动作?
  • Calculating the bore size: 更大的桶可以适应需要大的力和扭矩的应用.
  • Selecting the rod size: The length of the cylinder stroke, 轴承载荷和杆的屈曲强度可以帮助确定合适的杆尺寸. If standard cylinders are unusable with the bore size, custom cylinders can be manufactured for the ideal fit.
  • Examining the cushion options: If the hydraulic application requires the cylinder rods to move at high speeds, cushioning can be used at either cylinder end to dampen the impact.

What Are Hydraulic Linear Actuators Used for?

液压直线执行器在全球各个角落都有无数的应用. 与其他执行机构相比，液压缸效率更高，动力更强，更耐用. In the mobile equipment industry, hydraulics are exclusively used on excavators, bulldozers, dump trucks, graders and loaders.

Manufacturing plants rely on hydraulic actuators to operate forging presses, injection molders, compactors and other heavy equipment.

Single-Acting Hydraulic Cylinder vs Double-Acting

液压设备和机器采用单作用和双作用sb沙巴体育投注, and each type has its advantages. 单作用sb沙巴体育投注比双作用sb沙巴体育投注更简单，更容易维护. However, with more fluid in the pressurized chamber, double-acting actuators are easier for an operator to control.

Hydraulic Cylinder Suppliers

As leading hydraulic cylinder suppliers for over 50 years, 我们为客户提供各种sb沙巴体育投注和维修任何品牌或风格的sb沙巴体育投注. Here are some of the hydraulic linear cylinders we offer:

Along with this vast inventory of cylinders, we can also design and build a custom cylinder that meets your needs.