Caterpillar 3e-9205 Electromagnetic valve assembly D7R D6R

Basic information

Mark: Caterpillar.

Some models: 186-1525, 398-0940, 3E-6424, 7G8765.

Type of product

According to the purpose: electromagnetic valves for controlling fuel injection, electromagnetic valves for controlling the air inlet and release of air, electromagnetic valves for the canister with carbon, etc.

According to the operating mode: a normally closed type of electromagnetic valve, for example, 186-1525.

Working parameters

Voltage: 12 V DC, 24 V DC are common.

Type of connector: for example, a 2-pin connector.

Thread size: for example, 3/4-16.

The scenario of application

Engineering: hydraulic system, fuel system, excavators control system, bulldozers, loaders and other equipment.

Engines: used to control fuel injection, inlet, exhaust and other controls of various Caterpillar engines, such as C7, C9, 3306, etc.

Production process

Material: The valve body is often made of steel, alloy steel and other materials to ensure strength and durability.

Processing: a strict production process and high manufacturing accuracy provide stable operation and reliability of the electromagnetic valve.

A detailed method for eliminating the malfunctions of the electromagnetic valve of the crankcase

1. Elimination of reel malfunctions

1. External inspection

Carefully inspect the unlenoid coil for obvious signs of physical damage, such as burning, color change or breakdown. If you find traces of burns on the surface of the coil, this usually means that the coil was exposed to high temperatures and could be closed.

Check the insulation of the coil for the presence of cracks or excesses, which can lead to a short circuit or leak. If the insulating layer is damaged, additionally check if you are exposed, whether you are torn off, etc. The internal wires.

(II) Resistance measurement

Using the multimeter resistance range, tape the measuring wires of two electromagnetic coil terminals. Under normal conditions, the reel resistance value should be within the limits specified in the product specification. If the measurement result shows that the resistance value is close to zero, this means that the coil can be closed adherently; If the resistance value is endless, this means that the coil is open.

Compare the resistance values ​​of the coils of electromagnetic valves of different parties or the same model that work normally. If the measured current value deviates greatly from the normal range, even if it does not reach a short circuit or cliff level, this may mean that a problem arose, for example, a partial damage to the winding.

(III) Power on

In order to ensure safety, supply power to the electromagnetic valve and measure the temperature of the coil surface using an infrared thermometer. If the temperature of the coil quickly rises in a short period of time, even significantly leaving the normal range of operating temperatures, this may be associated with a short circuit inside the coil, which leads to excessive current and heating.

Pay attention to whether the coil makes any unusual sounds when feeding, for example, excessive buzz. An abnormal sound can be caused by an unbalanced electromagnetic force of coil or vibration of an iron core, which can also be associated with a malfunction of the coil.

2. Elimination of malfunctions of the valve core

1. Dismantling and inspection

Carefully disassemble the electromagnetic valve and remove the valve core node. Check if there are scratches, wear, deformation, etc. On the surface of the valve core. If there are obvious scratches or wear on the surface of the valve core, the gap between the valve core and the valve body may increase, which will affect the efficiency of the compaction and accuracy of movement.

Check the strength of the connection of the valve core with the spring, and also check if the spring is broken, whether it is deformed and whether it has lost its elasticity. Due to the breakdown of the spring, the valve core will not be able to normally return to its original position, which will affect the normal operation of the electromagnetic valve.

(II) Test action

After extracting the valve core from the valve body, press the valve core manually to feel the smoothness of its movement. Under normal conditions, the valve plunger must freely move in the valve case without obvious seizure or resistance. If you feel strong resistance when clicking on the valve core or you can’t even click it, this may be due to the fact that pollution got into the valve body and stuck between the valve core and the valve body, or the surface of the valve core is damaged, which leads to an increase in friction .

Check if the valve core in the valve body corresponds to the requirements. The maximum course of the valve core can be measured using a tool such as a caliper, and compared with the standard value specified in the product specification. If the course is insufficient or too large, this can affect the normal operation of the electromagnetic valve.

(III) fluid check

Check if the clean liquid passing through the electromagnetic valve. If the liquid contains impurities, particles, etc., they will most likely enter the valve body and lead to the stuck of the valve core. At the inlet of the liquid, you can install the filter and regularly check the filter clogging to determine the degree of fluid pollution.

Check whether the properties of the liquid correspond to the applicable electromagnetic valve range. For example, if an electromagnetic valve is suitable for a certain liquid or gas, but the actually used liquid does not meet the requirements, this can lead to corrosion or damage to the valve core and seals.

3. Elimination of malfunctions associated with impaired tightness

1. External inspection

Check the appearance of the seal for traces of aging, deformation, cracks or damage. The aging of seals is usually manifested in the hardening of the surface, the loss of elasticity and the darkening of the color; Deformation can lead to the fact that the seal cannot be correctly installed in the sealing groove; Crossing and damage will directly lead to the failure of the seal.

Check if the seal is correctly established and if there are distortions, deviations, etc. The wrong installation is one of the common reasons for the failure of the seal. Even if the compaction of good quality, the wrong installation will affect the effectiveness of the compaction.

(II) Detection of leaks

When operating the electromagnetic valve, carefully check the connection of the electromagnetic valve to the pipeline, the butt surface of the valve body and other possible leaks to make sure of the lack of fluid leakage. You can apply soapy water to these places. If bubbles appear, this means that there is a leak.

Some small leaks are difficult to notice with the naked eye. At this stage, you can use the testing equipment under pressure to test the pressure in the system where the electromagnetic valve is located. Close the appropriate valves to maintain a certain pressure in the system, and observe whether the pressure drops. If the pressure drops significantly, this means that there is a leak in the system and it is necessary to conduct a further study of the leakage.

(III) Checking the material of the seal

Make sure that the seal material meets the working requirements of the electromagnetic valve. Various liquids and working media present various requirements for sealing materials. For example, in high temperatures, sealing materials resistant to high temperatures are required; Corrosion liquids requires sealing materials resistant to corrosion. If the seal material is chosen incorrectly, this can easily lead to damage to the seal.

Check if the service life has expired. The seals are the wear of the details and have a certain service life. If the seal is used for too long, even if there is no visible damage in its appearance, it may lose its sealing properties due to aging and it will have to be replaced over time.

4. Elimination of problems of electrical connection

1. Checking forks/sockets

Check if you are deformed, are you oxidized, whether corrosion has been subjected to corrosion, etc. Metal tongues of the fork and sockets. A deformed tongue can fit loosely to a fork or outlet, which will lead to poor contact; Oxidation and corrosion will increase the contact resistance and affect the transmission of current. You can use sandpaper to carefully polish oxidized or corroded areas and restore good conductivity.

Check the reliability of the fastening of the wires in the fork, as well as their reliability and lack of weakening or disconnection. An unreliable connection of the wires will increase the resistance of contacts and will lead to the impossibility of proper operation of the electromagnetic valve. To pull up or fix the weakened wires, you can use a screwdriver or pliers.

(II) checking the wiring

Check the correct wiring according to the electromagnetic valve electromagnetic electromagnetic circuit. Check whether the power supply, control lines are connected, etc. In accordance with the requirements, and whether there are wrong connections or reverse polarity. Incorrect connection can lead to the refusal of the electromagnetic valve or even damage to the electromagnetic valve or the corresponding control equipment.

Check the chain for damage, short circuits or cliffs. To measure the resistance value or continuity of the circuit, you can use the resistance range or continuity of the multimeter. If the line of resistance of the line is abnormally large or endlessly, this means that the line can be broken; If the resistance value is approaching zero, a short circuit is possible.

(III) checking the control circuit

Check if the fuse has burned out in the control circuit. If the fuse blocks, this means that there can be problems in the control circuit, such as overload and short circuit. It is necessary to additionally find out the cause of the malfunction and replace the fuse before re -testing.

Check the correctness of the relay, contactors and other components in the control circuit. It is possible to determine whether the component is faulty by observing its work and measuring its operating voltage and current. If the component in the control circuit fails, this can also lead to improper operation of the electromagnetic valve.