The principle of hydraulic jacks, in more detail, why people can produce a lot of force with a small

The principle of the hydraulic jack is as follows:

The working principle of a jack is a wrench.

Go up to drive the small piston up, the oil in the oil tank is sucked into the lower part of the small piston through the oil pipe and the one-way valve, the wrench is driven down when the small piston is driven down, the oil circuit of the lower part of the oil tank and the small piston is blocked by the one-way valve, the oil at the lower part of the small piston is pressed into the lower part of the large piston through the internal oil circuit and the one-way valve, the pressure of the lower part of the small piston increases dozens of times due to the lever effect, the area of the large piston is dozens of times that of the small piston area, and the oil pressure generated by the manual is squeezed into the large piston, by Pascal's principle.

The area ratio of the piston is the same as the pressure ratio.

In this way, the force on the hand is increased by more than ten times (15 times temporarily) through the wrench to the small piston, and the force from the small piston to the large piston is increased by more than ten times (15 times temporarily), and the force = 15x15 = 225 times the force of the large piston (the movable part stretched out when topping the car), if the hand uses every 20 kg of force, it can produce 20x225 = 4500 kg (ton) of force. That's how it works. When it is used up, there is a valve that normally closes to open manually, and the oil is squeezed back into the tank by the weight of the car.

Pascal's Law.

It can only be used in liquids, where due to the fluidity of the liquid, a change in pressure that occurs in a certain part of the stationary fluid in a closed container will be transmitted in all directions without changing in size. The pressure is equal to the applied pressure divided by the area under force. According to Pascal's law, applying a certain pressure to one piston in a hydraulic system must produce the same pressure increment on the other piston.

If the area of the second piston is 10 times the area of the first piston, then the force acting on the second piston will increase to 10 times that of the first piston, and the pressure on both pistons will be equal.

First, the jack handle is a labor-saving lever for depressing the piston, and the labor-saving multiple is very large;

Second, there is an area ratio between pressing down the piston and jacking up the piston, which is also a labor-saving design.

Therefore, the hydraulic jack has fully realized the "four or two dialing jacks".

Assuming that the area of the piston of the manpower pressure rod is 1 square centimeter, and then assuming that the piston area of the ejector rod is 100 square centimeters, then only 1 kilogram of force can be used to lift 100 kilograms of heavy objects.

Hydraulic jack, also known as hydraulic jack, is a kind of jack that uses a plunger or hydraulic cylinder as a rigid jack lifting piece, a simple lifting equipment.

In principle, the principle on which the hydraulic jack is based is Pascal's principle, that is, the pressure of the liquid is consistent everywhere, so that in a balanced system, the pressure exerted on the smaller piston is smaller, and the pressure exerted on the larger piston is also larger, so that the liquid can be kept stationary.

Therefore, through the transfer of liquid, different pressures at different ends can be obtained, so that a transformation purpose can be achieved. The hydraulic jacks we commonly see use this principle to achieve force transmission.

Classification

Hydraulic jacks are divided into: general hydraulic jacks, special hydraulic jacks.

General hydraulic jacks are suitable for all kinds of lifting operations with small lifting heights. It is composed of oil chamber, oil pump, oil storage chamber, piston, rocker, oil valve and other main parts. When working, as long as the reciprocating lever is wrenched, the manual oil pump is constantly pressurized to the oil cylinder, and due to the continuous increase of oil pressure in the cylinder, the piston and the weight on the piston are forced to move upwards together.

When the return valve is opened, the high-pressure oil in the cylinder flows back into the oil storage chamber, so that the weight and the piston fall together.

Special hydraulic jacks are special tensioning tools that apply tension to prestressed steel bars when making prestressed concrete components. Special hydraulic jacks are mostly double-acting. There are two commonly used types: piercing type and cone anchor type.

The through-center jack is suitable for tensioning steel bundles or wire bundles, which are mainly composed of tension cylinders, top pressure cylinders, top pressure pistons and springs. It is characterized by a piercing hole along the axis of the stretching machine, and the steel bar (or steel wire) is anchored by the tool anchor at the tail after penetration.

The hydraulic jack can lift a very heavy sail with a small force, and it can save Kai and dismantle the work because of the state.

a.That's right. b.Mistake.

Correct answer: B

The working principle of hydraulic transmission is: with oil as the working medium, the movement is transmitted through the change of the sealing volume, and the power is transmitted through the pressure inside the oil.

A hydraulic transmission device is essentially a capacity conversion device, which first converts mechanical energy into hydraulic energy that is convenient for transportation, and then converts hydraulic energy into mechanical energy to do work.

Maintenance of hydraulic jacks

1) When the hydraulic jack is used, the bottom should be smooth and tough. Oil-free planks to enlarge the bearing surface and ensure safety. Iron plates should not be used instead of wooden boards to prevent sliding.

2) When lifting, it is required to be stable, and after the heavy object is lifted slightly, it is necessary to check whether there is any abnormal situation, and if there is no abnormal situation, it can continue to rise. Do not arbitrarily lengthen the handle or operate it too violently.

3) No overload, overload. When the red line appears on the sleeve, it indicates that the rated height has been reached and the jacking should be stopped.

4) When several hydraulic jacks are operating at the same time, there should be a special person to command the lifting or lowering synchronously. Wooden blocks should be supported between two adjacent hydraulic jacks to ensure spacing to prevent sliding.

5) When using hydraulic jacks, we should always pay attention to the sealing part and the pipe joint part, and we must ensure that they are safe and reliable.

6) Hydraulic jacks are not suitable for places with acid, alkali or corrosive gases.

It is to apply some pressure on the top of the piston, and then because the pressure of each part is always the same, the pressure exerted by Shan Xian can be directly transmitted to any other part, so the other side of the piston will also bear the pressure transmitted, so that the force will increase, and the weight will be lifted up, and the larger the area, the greater the force.

In principle, the principle based on the hydraulic jack chain is Pascal's principle, that is, the pressure of the liquid is consistent, so that in a balanced system, the pressure exerted on the smaller piston is smaller, and the pressure exerted on the large piston is also larger, so that the liquid can be kept stationary.

It follows Pascal's principle. This mainly makes use of the piston rod, which then creates a gas pressure.

Composition: large oil cylinder 9 and large piston 8 form lifting hydraulic cylinder. The lever handle 1, the small oil cylinder 2, the small piston 3, the check valve 4 and 7 form a manual hydraulic pump.

First, if the handle is lifted to make the small piston move upward, the volume of the oil cavity at the lower end of the small piston increases, forms a local vacuum, and the check valve 4 is opened at this moment, and the oil is sucked from the oil tank 12 through the suction pipe 5; Forcefully press down the handle, the small piston moves down, the pressure of the lower chamber of the small piston rises, the check valve 4 is closed, the check valve 7 is opened, and the oil of the lower chamber is input into the lower chamber of the lifting cylinder 9 through the pipeline 6, and the big piston 8 is forced to move upwards and jacks the heavy object.

Second, when lifting the handle again to absorb oil, check valve 7 automatically closes, so that the oil can not flow backwards, thereby ensuring that the heavy object will not fall by itself. By constantly reciprocating the handle, the oil can be continuously pumped into the lower cavity of the lifting cylinder, so that the heavy object is gradually raised.

3. if the stop valve 11 is opened, the oil of the lower chamber of the lifting cylinder flows back to the oil tank through the pipeline 10, the stop valve 11, and the heavy object moves downward. This is how hydraulic jacks work.

The internal oil circuit and working principle of the hydraulic jack.

Because of Pascal's law: the pressure applied to a closed liquid can be transferred by the liquid in all directions without changing the magnitude. When the hydraulic jack is operating, the small piston can produce a lot of pressure, so that the large piston can receive the same large pressure, and because the large piston has a large force area, the pressure generated is much greater, and the car can be lifted.

There are several kinds of mechanical jacks and hydraulic jacks, the principles are different From the principle, the most basic principle based on hydraulic transmission is Pascal's principle, that is, the pressure of the liquid is consistent everywhere, so that in a balanced system, the pressure exerted on the smaller piston is relatively small, and the pressure exerted on the large piston is also relatively large, so that the liquid can be kept stationary. So through the transfer of liquid, you can get the nos on different ends.

Hydraulic jack, it works on the principle of levers.

It is the principle of a double-cylinder pump, with an additional oil storage chamber.

The internal oil circuit and working principle of the hydraulic jack.

The main principle is that the internal pressure of the liquid is equal, and the output force is related to its area of action.