Operating principle of the generator overrunning clutch

Overrunning clutch failures

Having understood why a coupling on the generator shaft is needed, it is necessary to take into account the nuances of operating this consumable part:

• breakdowns are usually caused by wear of the clips and their jamming relative to each other
• The frequency of replacement is indicated by the manufacturer on the packaging; on average, it is 100,000 km of vehicle mileage.

Once the races are jammed, the overrunning clutch actually becomes an ordinary pulley. But in some cases (rollers spilling out), the adhesion of the pulley to the generator armature completely disappears, and the generation of electricity stops. In the latter case, the car will travel a short distance until the entire battery charge is used up.

In the bottom photo, the right clutch has exhausted its service life and was used correctly. The left part rusted without a protective cover and jammed, as evidenced by the shiny surface of the pulley grooves. In the sample center there is a new coupling with no real service life.

Rice. 8 Comparison of new and two used couplings

Device

Why is car crankcase protection needed?
The simplest overrunning clutch consists of two rings inserted into one another. Transverse grooves are machined on the inner surface of the outer ring. On the inner one there are either spring-loaded balls or rollers, or petals that rest against the outer ring. The design is made in such a way that in one direction of rotation the balls, under the action of springs, move out of the grooves and jam both rings, and in the opposite direction (or in the case when the outer ring moves faster than the inner) they are recessed and the rings rotate independently. If rotary paddles are used, they operate in the same way. There is also an option when the moment is transmitted through a spring wound on one of the shafts. In one direction, the spring tightens and connects the shafts, and in the opposite direction, it loosens and releases them.

Overrunning clutch device

An elementary overrunning clutch consists of two rings inserted into one another. The surface of the outer ring contains specific grooves, and the surface of the inner ring contains spring-loaded balls or petals with which it rests against the outer one. These rings interact in such a way that when rotating in one direction, the balls or petals contribute to the joining of both rings and they depend on each other during rotation, but in the opposite movement they are recessed and the rings rotate independently of each other.

Types of overrunning clutches:

• freewheels are ratchet and friction;
• friction ones, in turn, according to their layout, are divided into couplings with axial and radial closure, and according to the design of the elements - into wedge, spring, tape and others;
• Wedge clutches also come in several types: wedge and roller overrunning clutches. Roller overrunning clutches are the most widely used.

Friction overrunning clutch

Generator pulley

Friction overrunning clutches are silent and can operate at high speeds. They are used in cars, motorcycles, bicycles, machine tools, etc. In a bicycle, a freewheel allows the wheel to roll freely along the road when the pedals are stationary and transmits torque to the wheel when the pedals are rotating, which is why it is called a freewheel.  

The roller friction overrunning clutch (Fig. 28.17) consists of two coupling halves, between which rollers are placed in wedge-shaped gaps, which are pressed out by springs. When transmitting torque, the rollers are jammed between the coupling halves in the tapering part of the gap, forming a rigid clutch.  

The main application is friction overrunning clutches with rollers.  

The main application is friction overrunning clutches with rollers. The roller overrunning clutch (Fig. 313) consists of a sprocket, an annular race and rollers. The sprocket and the holder form halves tapering in one direction, in which the rollers are located. This design is the most technologically advanced. Couplings are made primarily with three rollers (small coupling sizes) and with five rollers (large sizes), but if increased load-bearing capacity is required with limited dimensions, a larger number of rollers can be used. Each of the rollers is pressed by springs into the tapering part of the cavity.  

The main application is friction overrunning clutches with rollers. The roller overrunning clutch (Fig. 313) consists of a sprocket, an annular race and rollers. The sprocket and cage form cavities tapering in one direction in which the rollers are located. This design is the most technologically advanced. Couplings are made primarily with three rollers (small coupling sizes) and with five rollers (large sizes), but if increased load-bearing capacity is required with limited dimensions, a larger number of rollers can be used. Each of the rollers is pressed by springs into the tapering part of the cavity.  

Overrunning clutches are divided into ratchet and friction clutches based on the way the clutch halves engage. The most common are friction overrunning clutches with rollers, since they have almost no backlash and operate silently. An overrunning friction clutch with rollers (Fig. 19.16) consists of two coupling halves - an asterisk / and a cage of 2nd rollers 3, located in grooves between the sprocket and the cage that taper in one direction. Each roller is pressed by spring 4 into the tapering part of the groove.  

Overrunning clutches, depending on the method of coupling their coupling halves, can be ratcheted or friction. Friction overrunning clutches with rollers are predominantly used, since they have almost no backlash and operate silently.  

Overrunning clutches are divided into ratchet and friction clutches based on the way their coupling halves engage. Friction overrunning clutches with rollers are predominantly used, since they have almost no backlash and operate silently.  

Overrunning clutches come in gear, cam and friction types. In Fig. 294 shows the friction overrunning clutch, which is most widely used.  

Overrunning clutches are widely used in mechanisms for transmitting movement in one direction; they automatically close in one direction of rotation and open in the opposite direction. In Fig. 14, d shows a friction overrunning clutch with rollers.  

Revolver devices (feeders) are used to feed piece workpieces of various configurations with a thickness of over 0 5 mm. The periodic movement of the turret disk is carried out by worm, maltese, ratchet and friction (friction overrunning clutch) mechanisms.  

Replacing the overrunning clutch

What are car tires made of? What is rubber made of?

You can do the replacement yourself, but only if you have a special key that can be used to unscrew it from the generator pulley. You should prepare for the fact that you will also need to replace the air conditioning compressor, but only a specialist can make such a decision.

The clutch must be changed when any signs of wear are detected - as well as along with the generator armature and consumables.

What tools will be useful?

Requires special tools. The coupling fastening element is difficult to see, since it has a countersunk head and is protected by a cap. Only after dismantling the protection can you find the internal slots into which the key is inserted.

But it is not always possible to remove OMG even with a special tool. In some cars there is so little space between the alternator and the body that the key cannot fit. In this case, it is recommended to remove the generator first. Sometimes it is difficult to unscrew a fastener because the nut is screwed too tightly. If you can’t unscrew it in any way, use a pneumatic wrench.

Components of a special key with which you can remove the OMG:

• Double sided bat. At one end there is a hexagon, at the other there is a head with an adapter for a wrench. This device is designed to keep the pulley from turning.
• Nozzle with a polyhedron on the outside. The other side of the nozzle is equipped with a hexagon for unscrewing the fasteners.

In addition, to remove OMG you may need the following tools:

• Torx 8 wrench;
• key to 17;
• head ATA-0415;
• key for 14.

How to remove?

On some vehicles, the coupling can be removed on site, without dismantling the generator unit. But this is only possible if there is free space that allows access to the mechanism. The procedure must be performed in the following order:

• The negative terminal is disconnected from the battery.
• The pipe fitting is removed.
• The absorber barrel is dismantled and the hose is removed.
• After removing the barrel, the generator belt is dismantled. You will have to loosen the nut securing the tension roller.
• For removal it is better to use a hex bit. Use it to unscrew the coupling.

But how can you unscrew the OMG if it just won’t budge? To do this, you will have to dismantle and disassemble the generator, after holding it in a vice.

How to install a new one?

Installation is done in reverse. Don't screw it too tight. A protective cap and cover must be installed. If this is neglected, then over time dirt will get inside the mechanism, which will inevitably lead to failure of the assembly parts.

Can it be repaired?

As a rule, overrunning clutches are not repaired; they are simply replaced with new ones. And yet, repairing OMG is possible, but only professionals can do it. The clutch begins to slip even with slight wear of the inner surface, which is ground during repairs. The liners are also ground or replaced with new ones - it all depends on the degree of wear. On small couplings that do not have liners, the roller is changed. The liners are ground on a machine using a special device. Grinding is done complete with sprockets.

During assembly, it is important to ensure clear jamming of the rollers. During installation, it is necessary to achieve alignment of the parts

The movement of the coupling after assembly should be smooth.

Replacing the overrunning clutch yourself

This device is not easy to replace. This requires a set of special tools. And even if you have them, this process can cause a lot of difficulties. Some car models have too small a distance between the body and the generator. In this case, the key may simply not fit.

Necessary tool

In order to properly remove the coupling, you will need a special tool. The key for removing the generator overrunning clutch consists of parts:

1. Bits . At one end there is a hexagon, at the other there is a pressed head under the knob. She turns and holds the pulley;
2. Nozzles with polyhedrons . Serves to install the internal spline of the coupling. On the other side there is a hexagon for unscrewing the fastening parts.

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Removing the coupling

To perform this action, you need to loosen the alternator belt. Then you need to unscrew the nut that holds the coupling. This device is non-separable and cannot be repaired. To remove the clutch, you must hold the pulley shaft with a suitable tool.

Next, the generator rotor shaft must be turned counterclockwise if the threads on the pulley are located on the right. For a pulley with a left-hand thread - clockwise. This is done using a torque wrench.

The protective cap is not reusable. When installing a new coupling, it must be replaced, having first made sure that the required device is correctly fastened.

Installation of the coupling

The new coupling is installed in place of the removed one in the same sequence. It is important not to use impact instruments - this may cause damage.

Checking the operation of the new clutch consists of twisting it in different directions. It should only rotate in one direction. When turned in the opposite direction, the clutch moves along with the generator pulley.

DIY replacement

To ensure the service life declared by the manufacturer, the overrunning clutch is equipped with a protective cover. If the owner/service employee forgot to install it or it falls off during use, dirt/dust penetrating into the clips may jam the rollers.

Tool

A special head will help you unscrew a jammed overrunning clutch. The asking price is 170 – 500 rubles, there are several options for equipment:

• with teeth at the end in the middle part and a 1/2" connecting square for VW, Skoda, Mercedes, Ford, BMW, Audi and some other cars
• hexagon 17 and connecting head 10 for Toyota and some other Asian and hexagon for the generator coupling of VAG cars

Service keys allow you to dismantle the coupling without removing the generator from its seats.

Rice. 9 Set of sockets for dismantling overrunning clutches of any manufacturer

Diagnostics

Incorrect operation of the generator overrunning clutch is determined “by ear” and mechanically:

• Whistling, rattling noises in the passenger compartment indicate poor tension, misalignment or worn seating surfaces (“grooves”) of the pulley
• If you jam the forced air cooling impeller of the generator with a screwdriver, the clutch should rotate in the opposite direction freely, in the working position for some part of the rotation, until the rollers rise up to synchronize the rotation of the shaft and pulley

If the clutch races jam, you should immediately replace the consumable with a new product.

Dismantling

Even with an external inspection of the coupling after removing the protective cover, it becomes clear why it is necessary to use a special service key. Instead of a conventional mounting bolt, a serrated surface is used here, which requires a tool with counter splines.

Rice. 10 Dismantling the coupling

The equipment is inserted inside the coupling, the teeth are engaged, the part is unscrewed with an open-end wrench or a socket with a ratchet.

Installing the overrunning clutch

After dismantling the jammed overrunning clutch, a new part is installed in an illogical way. The main nuances of the replacement operation are:

• tightening force 70 – 90 Nm
• installation of a protective cover to prevent dust and dirt from entering the holder

Rice. 11 Installing a new coupling

Rice. 12 Coupling protection cover

If a generator was used in the car without an overrunning clutch, it is enough to select a modification of the part with similar seating surfaces for the shaft and belt. These diameters must match completely.

Thus, even experts do not have a consensus on the advisability of using an overrunning clutch instead of a traditional pulley. The payback of this expensive product is questionable given the budget price of belts and pulleys without two cages with rollers inside. But the main purpose is to smooth out the moments of inertia on the shaft; the overrunning clutch performs it in full without any complaints.

What is a generator overrunning clutch?

This is a mechanism that allows you to eliminate the moment of inertia and impulse operation of the machine engine. The overrunning clutch is installed on the generator pulley.

Purpose

The function of the clutch is to remove inertia from the rotor, which is applied to the generator belt. This allows you to extend its service life from 30 thousand km. (as it was before, before the development of the device) up to 100 thousand km.

Device

The generator overrunning clutch consists of two cages:

• external, connected to the generator pulley;
• internal, connected to the generator armature shaft;

Between them there is a layer of special rollers laid in two layers:

• Level 1 - needle bearings;
• Level 2 - profiled figures. They are needed to act as a locking mechanism.

These clips are integrated into each other.

Principle of operation

When the engine starts running, the rotation of the outer clutch race begins to increase. The rollers acting as a locking device are locked. In this case, the outer part is connected to the inner one. At the same time, the generator shaft and pulley unwind.

When work stops, exhaust gases begin to escape. This slows down the rotation of the crankshaft. The inner part of the cage is faster than the outer one in rotation. At the same time, the locking mechanism opens and its connection with the outer part of the coupling becomes weaker. Because of this, the inner race stops braking.

This is a full cycle of operation of the device unit. One process follows another. In this case, the inertia from the belt is transferred to the pulley and the generator belt.

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Overrunning clutch design

Unlike the classic generator pulley, the operating principle of the overrunning clutch is much more complicated:

• the inner race is pressed onto the generator shaft
• the outer race is motionless relative to the pulley
• the rollers are located between the clips in several rows
• when the generator armature is accelerated by the crankshaft, the rollers move upward due to centrifugal force, the engagement becomes rigid, these shafts rotate at the same speed
• at the moment of compression of the fuel mixture in the cylinders there is no ignition, the crankshaft begins to lag in rotation relative to the generator shaft that has gained inertia due to the mass of the armature
• the inner race begins to overtake the outer one, the rollers fall down, the clutch of the assembly is disconnected

Rice. 7 Overrunning clutch design

After the next ignition of a portion of the fuel mixture in the combustion chambers, the cycle is repeated many times.

Ratchet and friction rotation synchronization devices are divided into several types:

• radially closed
• with axial locking
• tape modifications
• couplings with spring mechanisms
• wedge overrunning clutches

In passenger cars, wedge overrunning clutches are more often used due to their simple design and low manufacturing cost. In addition to two rows of rollers and a pair of clips, the design includes the following parts:

• splined profile for installation and removal of the coupling
• elastic gasket
• polymer cover
• contact plate into which the oil seal is mounted

Without a cover, operating the rotation synchronization device is strictly prohibited.

Why do you need a generator overrunning clutch?

Let's consider such a unit as the alternator overrunning clutch, why such a car part is needed and why it extends the life of the belt.

It’s strange to imagine, but before there was no such unit in cars. True, the alternator belt “flew” after a couple of tens of thousands of kilometers. Why did this happen?

It's all about the jumps in engine performance. Indeed, his work is impulsive. Everyone knows that for every 2 revolutions of the crankshaft, the mixture burns in the cylinders. At this moment, a sharp acceleration in torque transmission is observed. But then comes the turn of the gas outlet, which causes drawdown. Can a belt withstand an infinite number of such changes?

Of course not. Therefore, its service life was short. Here, to everything else, we must add such factors as the inevitable modes of braking, acceleration, stopping and starting. All these operations significantly reduce the service life of the belt and render it inoperable in a very short time.

So the smart heads started thinking - is it possible to extend the life of this part? Is it possible to somehow smooth out the unevenness of the engine cycles?

And they came up with an idea. We designed an overrunning clutch for the generator. Why this design was needed is clear from what was said above. Now let's look at what this node looks like structurally.

The overrunning clutch was simply taken and built into a regular generator pulley.

Moreover, the outer race of the product is mounted on the pulley, the inner - on the generator armature shaft.

Now the principle of operation of the overrunning clutch and why it is needed becomes clear.

The thing is that thanks to this design the inertial effect is dampened.

When the fuel mixture burns, acceleration of the armature is observed. At this moment, the locking rollers close both parts of the overrunning clutch cage, and the torque goes to the anchor.

But at the moment of fuel compression, the rotation speed of the outer race begins to decrease, and the races become disconnected. In this case, the anchor begins to rotate independently. This way, jerks and impulses are minimized.

But why was the generator chosen as the object for such minimization? Everything is simple here.

Progress does not always stand still, each new car model becomes even “cooler”, even more sophisticated. The number of electricity consumers in a car is constantly increasing. Accordingly, designers have to increase the size of the generator itself and, of course, its rotor. This increases the moment of inertia. This is what the generator overrunning clutch extinguishes.

So, it’s clear why an overrunning clutch is needed.
How the device works is also clear. And to really imagine its work, you can remember how the hub of a rear bicycle wheel functions. Same principle. August 11, 2017Teor21

Advantages and disadvantages

Many manufacturers install an alternator overrunning clutch at the factory. In this case, the owner does not need to improve anything, but the resource of this unit should be taken into account for timely replacement. Every car enthusiast can visually distinguish the equipment of a generator:

• a regular pulley is always secured to the shaft with a nut
• The clutch cannot have a freewheel nut; most often its end is covered with a protective cover

Rice. 3 On the left is a regular pulley, on the right is an overrunning clutch

Since ideal designs do not exist in principle, an overrunning clutch, in comparison with a conventional pulley, also has pros and cons, discussed below.

Resource

Since repair of the moving parts of the generator is necessary, both when operating a conventional pulley and when using an overrunning clutch, the service life of the entire set of kinematic diagrams of the V-belt drive should be taken into account:

• the pulley is ordinary - the grooves wear out and become unusable after about 200,000 km
• overrunning clutch - according to the manufacturer's requirements, replacement is required every 100,000 km
• belt - depending on the specific brand, car model and kinematic diagram, changes after 25 - 50 thousand mileage

Rice. 4 Regular alternator pulley

Rice. 5 Overrunning clutch

Rice. 6 Alternator belt

In other words, if under the hood of a car the generator is driven from the crankshaft by an individual belt, then it is more profitable to use a regular pulley. In the case of driving several consumers with one belt (furnace, air conditioning compressor, etc.), it is advisable to install an overrunning clutch on the generator, if the manufacturer has not already done this on the conveyor.

Maintainability

For both the regular pulley and the overrunning clutch, repairs are not economically profitable. Therefore, these consumables are changed entirely, but for different reasons:

• the pulley is relatively cheap, there is no point in handicraft soldering and grinding the “grooves” for the belt seats - this will cost more than a new part manufactured industrially
• Repairing the overrunning clutch is too complicated, which will also cost more than the cost of the part on store shelves

The belt is changed more often, but always as a whole; its maintainability is zero by default.

Generator overrunning clutch malfunctions

Types of breakdowns and their causes

Typically, the overrunning clutch fails under the following circumstances:

• pulley malfunction;
• wear of the inner spring;
• the alternator belt is broken;
• mileage more than 100 thousand km;
• overrunning mechanism malfunction.

Failure rates

Signs of a malfunctioning alternator overrunning clutch:

• during operation, unnatural noises are heard from the generator;
• complete stoppage of generator operation;
• When the air conditioner is running or when the machine is moving slowly, a noticeable vibration occurs;
• belt whistle at high speeds;
• short crackling sound when starting or stopping the engine.

Defect detection

To diagnose the operation of the unit, you should spin the engine to 4 thousand revolutions. Then you need to turn on the ignition. You need to listen to the residual sound. If it resembles the sound of a turbine stopping, then the generator clutch is working properly. If there is none, then the mechanism requires replacement.

The coupling can also be checked in a dismantled state; to do this, do the following:

• pinch the inner ring with your fingers;
• turn the outer ring in the direction of belt rotation;
• When the outer race moves, the coupling fails and needs to be replaced.

You can do the same experiment. But it is necessary to rotate the outer race in the opposite direction. In this case, on the contrary, it should rotate. If this does not happen, then the part has failed.

Application

with built-in ratchet overrunning clutch

This is how an overrunning clutch works: - this is the driving link, and - the driven one

Bicycle hub

Bicycle rear wheel brake hub. The inner ring of the overrunning clutch (item 6 at the top) uses rollers to force the outer ring (item 5 at the bottom) to rotate -

Overrunning clutches are widely used in the following applications:

• shaft turning devices of turbine units. The overrunning clutch ensures automatic engagement of the turbine rotor with the VPU drive when the speed decreases after turning off the turbine unit and disengagement when the turbine speed increases after it is put into operation;
• agricultural trailers from . The use of overrunning clutches allows you to avoid damage to the tractor transmission in the event that the trailer mechanics for some reason cannot rotate at the required speed;
• mechanical excavator cranes and lifting cranes with internal combustion engines, equipped. The overrunning clutch does not allow the turbine wheel and, accordingly, the machine mechanisms to rotate faster than the pump connected to the engine;
• in the rear hub of bicycles (except for);
• in the starting drives of many. Such engines are designed for a fairly low rotation speed, required only for starting. When the engine has already started and reached operating speed, the starter must be disconnected from it, which is done by the overrunning clutch even when the ignition key is still in the “start” position;
• in radio-controlled cars;
• helicopters, airplanes, with;
• in the paper path of printers and copying machines;
• in the mechanisms of spinning fishing reels;
• in the classic type, where they provide automatic redistribution of torque between the planetary gear links at the moment of turning on (off) hydraulically controlled clutches and brakes, which makes it possible to simplify the process of gear shifting (when switching to a higher gear, you do not need to smoothly disengage the clutches/brakes of the lower one), making shifting more efficient smooth, make shifts without interrupting the power flow and ensure that the car coasts in lower gears (overrunning clutches do not work in direct and overdrive gears). To ensure the possibility of engine braking, the overrunning clutches are blocked with additional hydraulically controlled brakes. The disadvantage of automatic transmissions with overrunning clutches is a significant increase in size and weight and the need for a large number of control elements (friction clutches, brakes). With the development of electronic control of automatic transmissions, transient processes when shifting gears are ensured by modulation of control pressure in the drives of friction clutches and brakes, with slip control, which allows you to change gears smoothly and without interruption in the power flow without the help of overrunning clutches. This allows you to reduce the number of control elements, the size and weight of the automatic transmission. For comparison, the automatic transmissions of similar-sized cars Audi Q7 and Toyota Land Cruiser Prado 150 each have 6 gears, but Audi does not have overrunning clutches, while Toyota does. Moreover, in the Audi automatic transmission there are only 5 controlled elements, while the Toyota has 8 plus three overrunning clutches. As a result, the automatic transmission with comparable engine power in Audi weighs 30 kg less than in Toyota. But to operate without overrunning clutches with the implementation of transient processes inside the automatic transmission clutches, Audi requires a special synthetic working fluid, a special ceramic coating of the working discs of the clutches and brakes, and placement of the electronic control unit directly in the automatic transmission pan (to reduce the inductance and active resistance of the electrical control circuits of high-speed modulated electromagnetic valves), while the Toyota automatic transmission, where transient processes occur in overrunning clutches, uses a widely used semi-synthetic working fluid, has a well-proven paper coating of the working discs, and the electronic control unit can be connected to the automatic transmission with fairly long wires;
• when the front differential is missing or locked, they are installed in the front wheels of a number of racing cars.

Application of overrunning clutch

Today, overrunning clutch is widely used in the following devices:

• agricultural trailers; electric starter motorcycles;
• rear axles of bicycles;
• starting drives of many internal combustion engines (in this case it is used to disable starters designed for low speed; the starter overrunning clutch is activated when the engine is started and reaches operating speed even if the ignition key is still in the “start” position).

A cross-section of the starter overrunning clutch looks like this (figure): 1 – casing; 2 – outer ring; 3 – roller; 4 – plunger; 5 – spring; 6 – spring stop; 7 – inner race; 8 – drive gear; 9 – starter armature shaft.

Separately, we can highlight the use of an overrunning clutch in the generator design. The generator overrunning clutch has the following functional purpose:

1. protects the generator from the effects of rotational vibrations of the engine crankshaft;
2. increases the service life of the belt because it reduces its vibrations;
3. reduces stress in the drive with a poly-V-belt; reduces belt drive noise.

Signs of a mechanism malfunction

Numerous tests by a number of independent automotive companies have proven the high efficiency of the inertia pulley. The design will reduce the load on important engine components, reduce noise and vibration levels. But, you need to understand that this mechanism also has its own resource - a little more than 100 thousand kilometers. Structurally, an overrunning clutch has much in common with a rolling bearing; malfunctions and symptoms are also identical. It can fail by jamming.

Main symptoms of a malfunction:

• Noise appears when starting the engine;
• Observation of tensioner clicks;
• Malfunction of the belt drive.

Breakdown can be caused by various factors: mechanical damage, dirt, incorrect installation of the generator, natural destruction. Further operation of the vehicle will result in accelerated wear of the alternator belt and other related elements

It is important to respond in time to the first signals of failure in order to quickly and with minimal financial costs eliminate the consequences of failure of the inertial pulley

Removing and replacing the generator overrunning clutch

Despite the fact that outwardly there is little difference between a conventional generator unit and an improved one, the method of dismantling them is somewhat different. In some models, the freewheel mechanism is extremely difficult to remove due to the fact that the distance between the car body and the generator itself is so small that it is simply impossible to get to it with a key. There are frequent cases of problems with fasteners; often even WD-40 does not help. To solve this kind of problem, professional auto mechanics recommend using a special key consisting of two removable parts.

Replacing the mechanism on SsangYong Kyron 2.0

To dismantle the overrunning clutch on a SsangYong Kyron SUV with a 2.0 engine, you need to equip yourself with a special key Force 674 T50x110mm. The wrench consists of a Torx-type slot, which is useful when removing rollers, and a socket with an external polyhedron. On the other side there is a hexagon for an additional key to release fasteners.

It is recommended to adhere to the following operating procedure:

1. The first step is to dismantle the engine protection and remove the fan casing.
2. The Torx 8 driver should be rested against the body and using a curved spanner set to “17”, unscrew the coupling.
3. After freeing the part, lubricate the threads and seat.
4. Lubricate the bearings, tensioner bushings and pulley.
5. Reassemble the unit in reverse order.

After finishing work, it is important to replace the protective cap.

Removing and installing the overrunning clutch on a Volvo XC70

The appearance of extraneous sound and vibration on a Volvo XC70 at low speeds is the first symptom indicating the need to diagnose the inertial pulley and, possibly, replace it. To carry out a quick and effective procedure for removing and replacing a structural element on this machine, you must do the following:

1. Arm yourself with a special head ATA-0415.
2. Remove the drive belt and remove the generator.
3. A hard-to-reach bolt can be easily released with a socket and a pneumatic impact wrench.
4. A new part is installed (INA-LUK 535012110).
5. Lubricate the parts and assemble in reverse order.

At this point, the work of dismantling and subsequent installation of a new mechanism can be considered complete. If necessary, bearings are also replaced at the same time.

Replacing the mechanism on Kia Sorento 2.5

A pulley from one of the most famous companies producing auto parts – INA – is suitable as a new copy of the overrunning clutch for the Kia Sorento 2.5. The price of the part ranges from 2000 to 2500 thousand rubles

It is also important to arm yourself with a special key - Auto Link 1427 worth 300 rubles

Once all the necessary tools and auxiliary materials are at hand, you can start working:

1. Release the bracket for the decorative engine cover.
2. Dismantle the “chip” and remove the positive terminal.
3. Disconnect all kinds of tubes: vacuum, oil supply and drain.
4. Using a 14 key, loosen the two generator mounting bolts.
5. Unscrew all tightening bolts.
6. Clamp the rotor in a vice, having previously prepared the gaskets.
7. Using a socket and a long wrench, remove the pulley from the shaft.

After which the failed mechanism is replaced. Next, you need to assemble the whole thing and install it back in its place. But spring-loaded brushes can interfere with this. To cope with the task, you need to unscrew the vacuum pump and find the hole opposite the brush assembly. The brushes are pressed and fixed in the hole with a characteristic sound.

How to check the alternator overrunning clutch?

A clear symptom that the clutch and belt are failing is a rattling sound in the cabin (the driver will not confuse this sound with anything) and significant vibration when the vehicle is moving slowly (or when the car is on the brake or in gear).

You can check the serviceability of the overrunning mechanism as follows:

• open the hood of the vehicle, start the car;
• spin the engine up to about four thousand revolutions;
• turn off the ignition.

After this, you need to listen to your “iron horse”. If you hear some residual sound, reminiscent of the sound of a turbine stopping, then the clutch is functioning quite adequately, and the problem is not with it. If the specified characteristic “sound” is not observed, most likely the overrunning clutch has exhausted its service life.

Malfunctions can occur for various reasons, for example, when dirt gets into the mechanism, due to improper installation of the generator and due to natural wear and tear. In principle, with a faulty overrunning clutch (if it is not jammed, of course), you can operate a car, but this is fraught with rapid wear of the belt drive and generator bearings. To avoid additional financial costs, it is better to fix the problem in a timely manner with your own hands or by contacting the nearest car service center. Repairing the coupling is not practiced; it is easier to buy a new part. You can change it yourself; to do this, you need to dismantle the generator and unscrew the coupling mounting bolt with a Torx bit, after which a new part is installed and secured with the same bolt.

Purpose and principle of operation of the overrunning clutch

As you know, the transmission of torque from the power unit to all its working elements is transmitted unevenly. The transmission of rotation resembles a more cyclical nature, which begins at the moment of combustion of fuel in the cylinders and lasts for two full revolutions of the crankshaft. In addition, these elements have their own cyclic indicators that are different from the crankshaft values.

The consequence of this is that the most important parts in the functioning of the power unit are subject to uneven loads, leading to their premature wear. And if we take into account the fact that the engine operates in different modes, the loads can acquire critical values.

Purpose of the overrunning clutch

The main problems of machine V-belt transmissions are traditionally:

• the crankshaft does not have a constant rotation speed, it rotates jerkily according to the fuel ignition cycles
• secondary shafts receiving rotation from the crankshaft have inertia, so they either lag or advance the generator pulley
• one belt is used for several units, which increases the moment of inertia, slipping of the belt occurs during moments of impulse transmission of rotation from the crankshaft
• the car moves unevenly with braking and acceleration, the engine periodically stops and starts up

Such an abundance of jerking and weakening inevitably leads to intense wear of the V-belt drive. The tensioner rollers suffer, the pulleys wear out, and the vehicle downtime for repairs increases.

Rice. 2 Operating principle of the overrunning clutch

The best example of synchronizing rotation using a freewheel is a bicycle. When untwisting the pedals, an analogue of this device ensures rigid coupling of the pedals with the rear shaft. During free rolling, the shaft continues to rotate and the pedals are disengaged so that the user can rest their feet on them.