Roller-timing belt tensioner: design features and types

In most modern cars you can find roller timing belt tensioner. It is necessary to ensure the normal operation of the internal combustion engine. Design at the movies can be various, everything depends on the adjustment type – manual or automatic. The principle of operation of these devices will be different, and significantly.

Main features of idlers

In essence, the tensioner of the timing belt 2108 or any other vehicle – it is an integral component of the actuator. With its help it is impossible to ensure the normal operation of the timing mechanism. As secondary tasks on the device switching function of the bypass roller.

Any actuator, which includes a flexible strap, are sensitive to drafts. If you increase the power, the elements of timing will wear out faster. And these are the components: water pump, generator bearings, crankshafts and camshafts. Even the teeth on the pulleys are erased faster. It also decreases the resource belt.

But if you pull too loosely, the belt will slip on the pulleys. As a result, slipping of the timing, the engine will run much worse. That is to maintain the operation of the motor in normal operation is present in the construction of a tension roller with manual or automatic adjustment.

Videos tensioning devices

In any tensioning mechanism has two main nodes:

1. Directly to the tensioner.
2. Video.

The Movie – pulley of metal or plastic, its working surface is smooth. It is installed on one - or two-row radial bearings.

On the roller working surface is in contact with the back side of the belt. During operation of the internal combustion engine this item is free to rotate. Design of the rollers can be perfectly smooth and with shoulders, so as not shifted the belt during operation.

Depending on what length of belt design drive system timing may be one or two rollers. Design 2110 timing belt tensioner only one. On 16-valve engines use two elements, but one of them - pass – the tension is not involved.

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Tensioner

The Tension mechanisms provide the most effective operating position for the roller. The device can be of such types:

1. Automatic – the tension is adjusted without human intervention.
2. Manual   adjustment is made at the service or repairs to the timing mechanism.

Manual tensioner can be a slide or eccentric. The last is a special sleeve in which the axis is shifted. Is the bushing inside the roller. When rotates around the axis of the tensioner relative to the belt changes the position of the roller. Therefore, changing the tensioning force.

This is the scheme that made a roller timing belt "priors". And here is a slide device moving at right angles to the plane of the belt, thereby providing a normal tension. The adjustment is made with a special screw. Such designs have not applied as they are harder and more massive eccentrics.

The Disadvantages of the tensioners with manual adjustment

As eccentric and slide devices has many drawbacks that affect the performance of the engine:

1. It is necessary to perform manual adjustment of the tension force. For this purpose use a dynamometer.
2. The wear and tension of the belt to keep track of the change in tension is almost impossible.
3. Sometimes you Need to adjust the tension.

But despite all the shortcomings, the new "Grant" rollers timing belt tensioner of the eccentric type are used. The design is proven and tested over the years, here only the state of the mechanism timing is required to follow. The use of automated devices will completely relieve the driver from conducting the adjustments.

Automatic tensioners

The design of these mechanisms include elements which provide adjustment of the tension in automatic mode. No matter what the wear of the belt, how fast it is stretched, the tension will remain at the same level. Through such mechanisms turns out to reduce the level of vibrations in the belt drive, to absorb various bumps and jolts. There are two types of automatic tensioning mechanisms:

1. Hydraulic – work with oil pressure.
2. Mechanical – the adjustment is made by means of springs.

In the last can be torsion springs or compression.

Mechanical device

Adjusting the belt tensioner the timing belt can be done by means of a spring. If you use a compression spring, the roller to the belt is pressed under the action of elastic forces. If used the coil spring, the lower edge engages with the base. And the top is the impact on the roller. The force with which the spring acts on the roller, is set by the manufacturer of the device. From the driver or the mechanic to STOrequires one – the right to set the mechanism. In adjustment it is not needed, the roller device is the most suitable position.

Accessories

They are more expensive and more complicated, but the efficiency is higher than in the spring. With their help it is possible to achieve the required belt tension automatically. They also allow you to change the tension force in a wide range. The basis is a cylinder, which is mounted in the following way:

1. Together with the roller on the bracket. The stock, which is located on the cylinder, abuts the bracket, or block of ice.
2. Directly on the engine block on the cylinder - rod rests on the roller, which moves together with the bracket.

Regardless of which cylinder design is used, they all have the same working principle. They include two cavities, connected to each other. They are divided by the piston device. The oil flows between the two cavities through the channels. The tightness of the belt transmission is controlled by oil pressure and a spring.