industrial hydraulic pumps hydraulic power pump hyd pump

3.3 valve plate and the cylinder surface with a stream of correction

Valve plate has a plane equipped with a flow and spherical flow two ways.

Deputy spherical friction with the flow in the cylinder with a relatively shallow stream surface scratches, after grinding technique amended; cylinder with flow surface grooves when the deeper, you should choose "the appearance of engineering skills" approach filled trench, then grinding , not blindly grinding ,, to prevent copper layer thinning or spill out of the steel substrate.

Plane friction pair assignment approach may be relatively high precision grinding on channels.

Cylinder and valve plate in front of grinding, you should measure the total thickness of the scale and the scale should be ground off, and then adjust compensation to the mat. Larger valve plate grinding amount, after grinding should re-treated to guarantee hardened layer hardness (Table 2).

Table 2 piston pump parts hardness specification

Referrals plunger rod hardware HS84

Referrals plunger rod ball hardness> HS90

Swash plate appearance referral hardness> HS90

Referrals valve plate hardness> HS90

After the cylinder block and valve plate correction, the choice of the following ways to view the status of cooperation in face of the leak that the flow in the disk with Vaseline oil, the drain channel blocked, painted with good oil flow channels on the flat plate or flat, and then placed on the cylinder valve plate, write diesel cylinder bore, an interval of oiling, ie an oiling hole, a hole is not oiling, surveys more than 4h, the plunger holes diesel no leak and collusion, and to clarify the cylinder valve plate grinding qualified.

4 Conclusion

Piston length of life using the number, and the usual maintenance of conservation, hydraulic oil quantity and quality of oil cleanliness and so on. Prevent oil particles in the form of piston friction pairs wear, but also an effective way to extend the number of piston life.

Replacement parts in the repair should be produced using original parts that sometimes more than other parts of the offer imitation expensive, but the quality and stability is better, if the purchase price of a cheap imitation parts, seems to be cost savings in the short term, But thus it brings out hidden dangers, but also may use form larger piston damage.

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High pressure pump

Works description:

Kawasaki negative flow system for high-pressure pump displacement control dispense controlled and electronically controlled two states

Electronic Control Status:

Changes associated with the displacement control signal is hydraulic pump oil flow before,

After the oil pump oil flow and pilot and negative flow

the amount,

Wherein the front and rear pump oil flow directly controlled high pressure fuel pump,

Pilot oil after electro-proportional control valve throttling high-pressure pump,

We can call it

For the pilot secondary pressure. We'll pump control as an example to analyze the changes in displacement below.

First, we must clear a few concepts

1.

Source displacement control signal is:

Before pump oil flow,

After the pilot secondary pump oil flow and oil flow and negative flow,

Wherein the front pump

Oil flow control a piston,

After a piston pump oil flow control piston and the swash plate

(End of the control piston of the small end of the swash plate,

It is often

Open state, end state control of the big end is normally closed, end of the control line pressure piston), a negative flow control piston, pilot two

Two times the oil flow control piston

2.

Control elements are

① spool:

Is a three-way valve,

It is composed by the spool and sleeve,

Relative movement between the two can.

Spool

Piston and secondary piston moves from the left end of the spring with the spool valve body constitutes the right level balance.

By moving the swash plate piston sleeve

Control, with the movement of the swash plate piston is moved, its distance and direction of movement of the piston with the swash plate consistent.

?② two pistons:

In the electronic control state,

Pilot secondary oil flow control two separate piston,

Negative flow does not participate directly

control,

But collected by the negative pressure sensor pressure parameter,

To the computer,

As calculated by the computer controlled electric current proportional valve

A parameter to control the pilot secondary oil stream;

In the pilot state,

Pilot secondary oil stream is truncated changed electronically controlled hydraulic valves,

Does not participate

The secondary piston control,

By the negative flow on the secondary piston alone direct control.

Secondary working direction of the piston is pushing the slide

The leftward movement of the valve spool, constitute the balance comes from the spring return.

?③ a piston:

Pump oil flow from the former,

After pump oil flow and the primary pilot oil flow

(In the pilot states only)

Control,

Direction of its work to promote the leftward movement of the spool valve body by its own spring return form balance.

3.

The actuator is a variable piston:

Variable piston fixed cross-sectional area of ??the piston sleeve and a plunger ends sample sizes constitute,

The plunger and the swash plate and

Slide valve sleeve connection, when the two end faces pressed to generate pressure, the plunger drive the other two sports together.

Let's analyze the hydraulic system pressure and flow control in concrete changes in the relationship between the high-pressure pump in the middle.

?guiding ideology:

1.

Pressure depends on the load

.2..

Pressure and flow high pressure pump output is inversely proportional.

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1, according to whether the flow can be adjusted can be divided into: variable displacement pump and metering pump. Output flow can be adjusted as needed is called variable displacement pump, the flow rate can not be adjusted is called a metering pump.

2, according to the hydraulic system commonly used pump structure is divided into: gear pumps, vane pumps and piston pumps three kinds.

Gear pumps: smaller, simpler structure, strict cleanliness requirements for oil, the price is cheaper; but the shaft by the unbalanced force, badly worn, a large leak.

Vane pump: two double-acting and single acting vane pump vane pump. The pump flow evenly, smooth operation, low noise, operating pressure and volumetric efficiency than gear pumps, complex structure than the gear pump.

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Piston: high volumetric efficiency, leakage small, can work under pressure, mostly for high power hydraulic system; but the complex structure, material and machining high precision, expensive, high oil cleanliness requirements.

Pump principle

Usually when a gear pump and vane pump can not meet the requirements for piston pumps. There are other forms of pump, such as a screw, etc., but not as good as the above-described three kinds of universal application

?????It provides pressurized hydraulic fluid to a hydraulic element hydraulic transmission, a pump. Its function is to power machine (such as electric motors and internal combustion engines, etc.) of mechanical energy into fluid pressure energy. Single-piston pump works cam is rotated by the motor, when the upward movement of the cam push the plunger, piston and cylinder form sealed volume decreases, fluid extruded from the sealed volume, is discharged through the check valve to go where they are needed. When the cam is rotated to dro parts of the curve, the spring forces the piston down, a certain degree of vacuum, the oil tank into the sealed volume at atmospheric pressure. Cam lift the plunger constantly, periodically sealed volume decrease and increase, the pump will continue to suction and discharge of oil.

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