When we understand the theoretical knowledge of hydraulic cylinders, we think that we are omnipotent, we will not encounter any problems when using hydraulic cylinders, and we are confident that we can solve various problems, but actually use hydraulics When using hydraulic cylinders, there will still be various problems that can’t be solved. Let’s talk about the problems that may arise in the actual application of hydraulic cylinders.
If you are asked to take over a R&D project for a piece of equipment, do you have a clear implementation idea in your mind, such as how to select the hydraulic cylinder of this equipment, and what should be paid attention to for the hydraulic cylinder of this equipment. So let me tell you what you need to consider when choosing a hydraulic cylinder.
1. How to install and fix the hydraulic cylinder?
There are 2 common ways to fix hydraulic cylinders:
1. The first type is a square hydraulic cylinder fixed on the B plate, and the hydraulic cylinder needs to be a positioning key on the B plate.
2. The second type is a circular hydraulic cylinder fixed on the thimble plate. It should be noted that the thimble plate locking screw needs to be added next to the hydraulic cylinder. This position is subject to large forces to prevent deformation.
3. Another point is to engrave on the hydraulic cylinder and write down the size, shape, number, brand and ejection stroke of the hydraulic cylinder for easy checking.
2. How to design the connection between hydraulic cylinder and template?
The hydraulic cylinder and the template are designed to be connected with a round T block. The template is designed into a U-shaped groove for easy processing and installation. The size of the mating surface is 8-12 mm, and the other positions are avoided 0.5 mm. The hydraulic cylinder joint has internal threads. External threads 2 Kind of, just lock the screw directly behind the T block for the inner screw.
Note: The size of the new head of the hydraulic cylinder. Tooth pitch is subject to the 2D description provided by the hydraulic cylinder company, especially if the pitch is not read, it is easy to make mistakes.
3. How to install the hydraulic cylinder joint and how to arrange the air pipe?
There are two types of hydraulic cylinder joints: inner thread and outer thread. The inner thread is directly locked behind the T block, and the outer thread needs to be tapped.
This is not the point to talk about. The T-block is round, which is not easy to clamp. It needs to cut 2 flat surfaces to twist the screws. This is the key. I have never done a fitter, and the design is often missed.
4. How to stop the rotation of the hydraulic cylinder?
Why should the hydraulic cylinder stop rotating? We can understand in this way that the moving piston in the hydraulic cylinder is not stopped, and may rotate during repeated overmotion, causing the screws to loosen and posing safety risks. Designing to stop rotation becomes necessary.
There are usually 2 design methods:
1. Make anti-rotation gasket
2. Lock headless screws
The first one is preferred, which is safer and more reliable.
5. Should hydraulic cylinders be designed with protection devices?
1. Hydraulic cylinder protective cover (as shown in the picture), large-scale automobile molds are generally made, small molds depend on customer requirements, and some even cover all hydraulic cylinders. The purpose is to prevent the mold from hitting during the hanging mold, the injection molding machine or the transportation process, and play a protective role. It is usually made of iron sheet. The hydraulic cylinder is installed on the side of the sky and the earth and also acts as an anti-tip board.
2. The hydraulic cylinder limit block is convenient for disassembly and assembly of the hydraulic cylinder, and prevents the locking screw of the fixed hydraulic cylinder from loosening and the hydraulic cylinder runs out, which is necessary.
3. The hydraulic cylinder support block is mainly used to offset the pressing of the hydraulic cylinder to prevent deformation. Another way is to add trash nails under the hydraulic cylinder.
6. How to design the oil circuit to eject the reset balance?
The purpose of the oil circuit ejection reset balance is to ensure the ejection balance, the length of the oil circuit is the same length, if it is not possible, it should be as short as possible not to exceed 50 mm. The oil circuit is designed to be vented to facilitate the discharge of iron filings and prevent iron filings from entering the hydraulic cylinder and affecting the work. At the same time, the oil pipeline throat plug must be tapped and cannot be blocked by copper. The main reason is that the oil pressure is large and it is easy to loosen and leak.
The following are several common oil circuit balance design schemes
1: 4 hydraulic cylinders are ejected, mainly large molds above 1500 mm, the oil circuit is designed on the B plate, and the oil inlet and outlet are designed on the non-operating side
2: 2 hydraulic cylinders are ejected, the oil circuit is designed on the square iron, and the oil inlet and outlet are designed on the non-operating side
3: 2 hydraulic cylinders are ejected, the oil circuit is designed on the square iron, and the oil inlet and outlet are designed on the sky side
7. How to design the hydraulic cylinder sensor switch?
Install one hydraulic cylinder induction switch for ejector reset, one set for each side of the large mold,
The sensor switch is installed on the insert with adjustable distance,
It can be realized by opening the U-shaped groove on the fixing screw of the insert. In addition, it is necessary to pay attention to the induction switch to be installed on the opposite side of the oil circuit joint to avoid interference with the oil circuit when it is ejected.
8. Matters needing attention
1. The ejection stroke of the hydraulic cylinder cannot interfere with the water collector, check the ejection distance S
2. The ejection stroke of the hydraulic cylinder cannot interfere with the lifting module. Check the ejection distance S. If it is unavoidable, remove it after installing the injection molding machine, and indicate on the mold installation nameplate.