Causes and solutions of automatic descent of Manifold Block hydraulic cylinder
The reason for the automatic slide of the hydraulic cylinder is:
1. The sealing ring is aging and worn.
Solution: Redesign the sealing structure or sealing ring
2. Hydraulic valve leakage or hydraulic valve spring fracture.
Solution: Replace the hydraulic valve.
How to reduce the failure rate of hydraulic cylinder
General manufacturers only know the use, do not necessarily know the sealing principle, the dynamic changes of seals, seals in the cylinder is how to work. Hydraulic cylinder manufacturers must understand the sealing technology, according to different technical requirements, choose different seals. The seal manufacturers must also understand the working principle of the oil cylinder and use different designs to meet the technical requirements of the oil cylinder. Therefore, the close cooperation between the cylinder manufacturers and the seal manufacturers is needed to reduce the chance of cylinder failure.
First, talk about several states of hydraulic seals (lip seal)
(1) When the seals are not installed, there are four dimensions, which can be seen by everyone and measured by measuring tools. The four dimensions are: the inner diameter of the root of the seal, the outer diameter of the root, the inner diameter of the lip and the outer diameter of the lip.
(2) when the seal is installed in the groove, the groove size is unchanged, and the size of the seal has all changed, the four dimensions are: the outer diameter of the seal root, the outer lip diameter changes to the outer diameter of the groove at the same time; The diameter of the inner lip is the diameter of the piston rod. The diameter of the root is the amount of clearance between the seal and the piston rod plus the diameter of the piston rod.
(3) When the cylinder starts to work and start the pressure, the working state of the seal is: the inner and outer lips are close to the inner and outer walls and move backward. The root of the seal is squeezed backward. With the increase of the pressure, the force of the hydraulic oil on the seal is increased, and the overall deformation of the seal is increased. When the working cycle is completed and the cylinder has no pressure, the seals return to their original state. Repeated deformation, repeated recovery, until the seal lips effective loss of all, the seal is damaged.
Two, hydraulic cylinder groove size tolerance and sealing parts
(1) There are many forms of reciprocating motion sealing, common L, U, V, and Y, etc., its shape is mostly lip seal.
(2) Reciprocating motion lip seal is widely used in the reciprocating motion of the hydraulic system cylinder. This seal compression face is lip type, there is a very small amount of interference in the installation, so that the lip edge and sealing face full contact, sealing effect. When the cylinder is working, with the increase of pressure, the contact force and contact area increase, and the sealing performance increases with the increase of pressure. When the hydraulic cylinder returns, the pressure decreases, the contact area and the contact force decrease, and the sealing performance decreases accordingly. This kind of lip operation process is similar to the human breathing process. In addition, this process also plays a role in the lubrication of the lip.
(3) Seal manufacturers in the world have strict requirements on the tolerance and roughness of groove size. Therefore, hydraulic cylinder manufacturers must strictly according to tolerance and roughness requirements to produce oil cylinders.