Today we will talk about how to determine Hydraulic cylinder The journey of.

1、 What is the stroke of the cylinder?

Hydraulic cylinder It is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion (or swing motion).

It is simple in structure and reliable in operation. When it is used to realize reciprocating movement, the reducer can be avoided,

There is no transmission clearance, and the movement is smooth. Therefore, in various mechanical Hydraulic system It is widely used in.

The stroke of the hydraulic cylinder refers to the action length of the piston rod, that is, the distance between the far point and the to The distance of the near point.

In short, the stroke from the bottom of the hydraulic cylinder to the full extension is the stroke of the hydraulic cylinder.

For the hydraulic cylinder with buffer device, the stroke of the cylinder also includes the buffer length.

2、 Relationship between design stroke and working stroke of hydraulic cylinder

Determine the stroke S according to the requirements of the overall design of the equipment or device system. If the selection space of the oil cylinder allows, please select the stroke ratio as required

Find the oil cylinder with long stroke to improve the expandability of the system and prevent the excessive extension of the oil cylinder.

The design stroke of the oil cylinder is greater than or equal to the working stroke of the oil cylinder (generally greater than a few centimeters of the working stroke).

3、 Specific determination principle of trip S

(1) Stroke S=Actual to Large working stroke Smax+stroke margin △ S;

Travel margin △ S=travel margin △ S1+travel margin △ S2+travel margin △ S3.

(2) The determination principle of travel margin △ S shall be comprehensively considered under general conditions:

Stroke margin required for manufacturing error of system structure installation dimension Amount △ S1

The stroke margin △ S2 that may be required at the beginning of the stroke and the stroke margin △ S3 that may be required at the end of the stroke during the actual operation of the hydraulic cylinder.

be careful: When the hydraulic cylinder has the requirement of buffer function, the stroke margin △ S will have a direct impact on the buffer function,

It is recommended to minimize the stroke margin △ S

(3) For long stroke

Exceeding the allowable range of this product sample to Long travel,

Or hydraulic cylinders under specific working conditions（ Load characteristics, installation mode, etc.) to check the stability of the hydraulic cylinder.

(4) For ultra short travel

Exceeding the hydraulic sample series and certain installation methods to If necessary, please check with the manufacturer for short stroke hydraulic cylinder Recognize.  

Generally speaking, the oil cylinder is an integral part of the whole mechanical equipment,

The stroke of the oil cylinder must meet the corresponding equipment action requirements to Large travel must be a priority.

After determining the stroke, determine the type of cylinder to Small installation size and to Large travel is directly related,

because The piston thickness, cylinder bottom thickness and guide sleeve thickness are relatively fixed, to Small size directly depends on to Large travel.

If to If the small size is still greater than the limit value of the installation position, multi-stage oil cylinder can be selected.

(5) For example:

When you choose the installation method of front and rear single ears of 63 cylinder diameter, the installation hole distance of front and rear single ears of HSG should be 305+S,

If the design stroke is 600, then The installation hole spacing is 905mm.

If a two-stage oil cylinder is used, if the design stroke is 600, the installation hole spacing is 625mm, which can greatly save installation space.

However, if you want to achieve the same thrust as the single-stage cylinder, the outer diameter of the second stage cylinder is much larger.

4、 How to select the stroke of double rod cylinder?

If the cylinder body is fixed, the piston rod is connected to the workbench,

Then the reciprocating motion range of the hydraulic cylinder is its effective Three times the distance.

If the piston rod is fixed and the cylinder block is connected to the workbench, the movement range is twice the effective stroke.

5、 How to accurately control the stroke of oil cylinder?

(1) Is there a standard for determining the itinerary?  

1. Some standard cylinders

The manufacturer will produce in batches, and the standard travel is mostly 50 mm, such as 50, 100, 150, 250, 300, etc.

For standard cylinders, if the stroke needs to be customized, such as 55mm,

The manufacturer's production cost includes the generation of new product codes and BOM lists The cylinder barrel piston rod needs to be reworked, and the whole cylinder needs to be assembled and tested.

Although the material costs are basically the same, the production costs and management costs have increased significantly, so the large-scale manufacturers are unwilling to accept such orders.

2. For non-standard oil cylinder

Travel 55 or 50 is basically the same for material and production costs.

(2) When the design stroke of the oil cylinder is 505, but you want the stroke to reach 500, the piston rod of the oil cylinder stops,

There are three ways to achieve this:

Method I

The use of fixed backers for accurate positioning is also called mechanical positioning method.

Method II

Use electronic displacement device.

For example, the magnetic induction oil cylinder, the main function of the magnetic switch is to check the operation of the oil cylinder piston.

When the magnetic ring of the oil cylinder moves slowly close to the magnetic induction switch, the magnetic reed of the magnetic switch will be induced, thus causing electric shock Close to generate signal;

When the magnetic ring of the oil cylinder leaves the area of the induction switch, the magnetic reed loses its induced magnetism,

So that the electric shock is disconnected Signal,

In this way, the position movement of the cylinder piston can be checked to control the action of the corresponding solenoid valve.

Method III

At the proximity switch, add solenoid valve control. Add travel switch. When touching the oil cylinder switch, the solenoid valve will reverse.