Hypoid oil. Criterias of choice

Hypoid transmission is widely used today. It is used for cars, tractors, diesel locomotives, and machine tools for light and heavy industries.

Did you know?The passenger car was equipped with a hypoid transmission in 1926 by the American Packard Company.

What is a hypoid gear and its purpose in a car

The hypoid gear is a helical gear train that works with bevel gears with crossed axes. In a car, it is needed to change the direction of the torque and change its magnitude, which improves the characteristics of the main gear. With the development of the automotive industry, the type of hypoid gears is gaining great popularity and is used not only in executive cars, but also budget cars... In any case, these are cars with a leading rear wheel drive, where the motor and the main gearbox are located parallel to the movement, and the torque is transmitted to the drive axle at right angles.

How does a hypoid gear reducer work?

Let's figure out how the hypoid transmission works and what it gives to the machine. In this transmission, the moment of force is transmitted from the engine through the clutch, gearbox and cardan to the axle of the hypoid drive gear transmission. The pinion pinion axle is installed parallel to the axes input shaft engine and gearbox output shaft. Due to the curved shape of the teeth of the gears of this gear, the transmitted torque is of greater importance than, for example, in a bevel gear. This improves the dynamic and mechanical performance of the machine.

Important!In hypoid gears, special fluids with high quality and properties (antiwear and extreme pressure additives) are used to lubricate its elements, making it possible for long-term trouble-free operation.

Pros of using a hypoid transmission in a car

The first advantage is the location of the driveshaft. It lowered significantly, which reduced the size of its channel in the cabin, evenly distributed the center of gravity of the car and increased its stability. Second, smooth transmission of torque, which improves the vehicle's driving characteristics.

An equally significant fact is the lower load and noise level. These indicators are due to the fact that a greater number of teeth are involved in the hypoid type of gearing, in comparison with the same bevel gear.

All these factors increase the durability of the machine, not to mention the comfort of movement. Therefore, the hypoid type of transmission is an integral part of cars. high class such as Infinity.

Interesting! The decision to release a new class of prestigious cars in the company "Nissan”Was adopted in 1985. The car was named "Infiniti", In translation - infinity, infinity.

Hypoid gear in the car: are there any disadvantages

TO disadvantages hypoid transmission refers to the possibility of seizing along the line of contact due to friction. To reduce such probabilities, the final drive gears undergo special processing during the manufacturing process.

In addition to the difficulty in manufacturing, there is a force during the rotation of the gears as their teeth are bent, this force is transmitted to the axles. These points make the hypoid transmission susceptible to wear and tear.

This transmission is demanding on the quality of not only gears, but also its other elements. If adjusted carelessly, it will jam, especially when changing the direction of rotation or engaging reverse gear.

Attention! If you get stuck on country road, for example, in a rut, you only need to pull out a shrunken machine in a forward motion, otherwise the gear teeth may break.

Few motorists know what hypoid oil is and what is it generally intended for? This lubricant is primarily intended for transmission units, but it is also used in steering mechanisms.

In the manufacture of these lubricants, the companies add many additives to the base oil that provide good extreme pressure properties. Similar transmission fluids belong to the GL-5 category and are suitable for transmissions of many modern Vehicle, in the bridges of which there are hypoid gears. This lubricant product is actively used to lubricate gearboxes and cardan shafts, and not only in cars, but even in helicopters.

What is hypoid oil?

A hypoid oil is a lubricant that is designed for ultra-high mechanical stress. Accordingly, this fluid is designed for the specific operating conditions inherent in hypoid transmissions.

Hypoid gears transmit torque by engaging a pair of gears with curved or oblique teeth. These gears are less noisy when running transmissions and can function long time without wear, provided that for their lubrication will be used suitable liquid- hypoid oil.

Between the teeth of hypoid gears, the engagement area is limited to a small contact patch, but all the force is concentrated pointwise. Due to this, the specific pressure at a particular point increases greatly. This can lead to the formation of scoring, which is dangerous for the gears. To avoid this, a good hypoid oil is required to maintain a reliable film at the contact points. Due to this film, the parts are in contact with a minimum coefficient of friction.

Properties of hypoid oils

Lubricating fluids intended for hypoid gears should contain up to 3-4 percent sulfur. On the one hand, it prevents the seizure of metals under the influence of extreme loads, and on the other hand, it causes oxidation of metal parts. To equalize these processes, unique additives are required.

For example, a special additive called MOLYVAN L significantly increases the protective performance of the formulation in harsh operating conditions. In this regard, in gearbox fluids, including hypoid ones, as well as in engine oils almost all manufacturers add this additive. The concentration of the additive can be up to 5 percent. Hypoid transmission oils designed for steering mechanisms and gearboxes can work normally at temperatures down to -30.

Appointment of hypoid oils

Hypoid drive axles some time ago began to be installed on all modern cars, and oil manufacturers began to produce suitable lubricants... For trucks the impetus for the emergence of hypoid gears was the emergence of worm gears. They were used by manufacturers of heavy-duty trucks.

Since the 50s of the last century, the direction of oils with universal properties that were suitable for all vehicles began to develop in foreign countries. The standards of the USA and England were used as a basis, according to which hypoid oils with a high concentration of phosphorus, sulfur and chlorine were produced.

Grease manufacturers from Germany actively conducted bench tests to obtain the most wear-resistant oils that did not corrode. V last years car manufacturers are increasingly installing hypoid drive axles that require a GL-6 class universal grease, so this fluid is losing demand.

At the same time, new types of oils appear, suitable for hypoid gears operating at high speeds. A complex additive with phosphorus and sulfur content VIR-1 has also appeared - it is used in various types of oils. Bench tests confirm the suitability of this additive, working under high loads and at high speeds, including with hypoid gears.

Cars with hypoid gears mainly use an all-season fluid that is designed for moderate climates. Hypoid oils prevent abrasive wear of surfaces through the use of formulations with a viscosity of SAE 90 and more. In terms of characteristics, these fluids differ little from traditional transmission fluids, with the exception of viscosity.

In the checkpoint, the most heavy wear gear coupling of worm gear, bevel gear and hypoid gear is subject to. At the narrow points of contact of the gear teeth, a rather heat... The oil film that covers the teeth is also exposed to high pressure, high speeds and temperatures. To lubricating fluid did not lose its original properties, and the surfaces of the parts did not wear out and the gear teeth did not seize, additives were added to it.

In industrial vehicles, transmissions are used to transfer power from the motor to the wheels or other assembly. The main difference is the transmitted power. All units are divided into hydraulic and mechanical. Structurally, a manual transmission with a hypoid transmission of forces does not fundamentally differ from other transmissions.

What you need to know about hypoid oils?

As already mentioned, hypoid gears are used in the final drives of many modern vehicles. Experienced motorists are well aware of which we had a separate detailed article. This fluid was previously used by the owners of all domestic cars, but when foreign cars began to appear actively in the country, the range of fluids for transmissions began to grow rapidly.

The main characteristic of hypoid gearbox oils is their viscosity. To date, all manufacturers of lubricants, including domestic ones, have switched to the SAE classification - it is used all over the world. This classification includes seven viscosity grades, including three summer and four winter.

Winter oils are additionally marked with the letter W:

• SAE70W;
• SAE75W;
• SAE80W;
• SAE85W.

As for summer classes, they do not add a letter to them, but they are marked as follows:

• SAE90;
• SAE140;
• SAE250.

It should be noted that seasonal oils rarely develop their operational resource over the winter or over the summer, so their use is not the most rational. In this regard, all-season hypoid fluids with a double marking of the SAE80W-90 type are more common among motorists.

With the exception of the viscosity grade, all transmission fluids are classified according to API characteristics - from GL-1 to GL-6. The higher this class, the more additives in the oil that support the operation of the mechanical assembly. As far as hypoid oils are concerned, they belong to one of three classes GL-4, GL-5, or GL-6.

Distinctive features of GL-4 and GL-5 oils

The first and most significant difference between these two fluids is their area of ​​use. GL-4 fluid is designed for gearboxes with hypoid or bevel gears. The contact stresses in them usually do not exceed 3000 MPa, and working temperature oil does not rise above 150 degrees.

As for GL-5, this lubricant is designed for normal operation of shock-loaded hypoid gears. These mechanisms can experience voltages in excess of 3000 MPa. This grease is used for units with limited slip differentials, as it guarantees normal protection of metal elements under high loads and temperature influences.

Among the important distinctive features oils GL-4 include the minimum content of sulfur-phosphorus additives. They provide a tough protective film that is significantly harder than some soft alloys such as copper. The use of GL-5 fluid in gearboxes where, according to the manufacturer's recommendations, an oil of a lower class should be used is unacceptable. Otherwise, it will cause the formation of metal chips and lead to wear on the mechanism.

What parameters should hypoid oil satisfy?

It is impossible to say unequivocally what criteria a hypoid gear oil must meet. A good lubricating fluid is one that is suitable for the operating conditions of a particular unit or unit. The oil selection criteria are determined by the car manufacturer individually, since all brands and even car models differ from each other.

Every car has its own design features therefore they require a certain class of grease. A hypoid transmission of one machine in terms of design and operating conditions may differ markedly from a unit of another vehicle that is similar in purpose. Multiple factors are important here, including:

• torque;
• axis offset;
• rotational speed;
• impact force and more.

Thus, if GL-4 fluid is optimal and recommended for a certain unit, then it may not be suitable at all for another transmission. Thus, when selecting a hypoid oil, read the vehicle manual.

The best hypoid oils for cars

V technical manuals all machines always have the information they need. If you are limited in finances, you can buy a liquid not from the recommended brand, but something cheaper, but the oil must match the viscosity grade. According to the results of many tests, the Motul Gear 300 fluid comes to the leading position of the rating. This hypoid oil has high protective properties, therefore, it prevents the appearance of scoring. The protection index is 60.1 units, as well as for oil good indicator welding. The oil film of this fluid is very stable, therefore it minimizes the coefficient of friction between the elements. The wear indicator is 0.75 mm. Among the disadvantages of this hypoid liquid, only weak viscosity indicators are distinguished at negative temperatures in winter.

Castrol Syntrans Transaxle is another popular hypoid oil that deservedly took second place in the ranking. Low temperature fluidity, high protection against scuffing and affordable price makes this product in demand among motorists. The fluid has a good wear rate of 59.4 units.

If for one reason or another you do not recognize Castrol oils, you can choose another brand - Mobil Mobilube. This oil possesses good viscosity-temperature characteristics, prevents oxidation and thermal degradation, and also works well with extended maintenance intervals. This oil is marketed as API GL4 / 5.

In the fourth position in the rating is Total Transmission SYN FE. In terms of the level of protection against scuffing, the liquid broke away from the previous products - it is equal to 58.8 units, which is considered a good indicator. Alas, drivers talk about low fluidity at low temperatures, as well as weak protection against mechanical wear.

LIQUI MOLY Hypoid-Getriebeoil also has good performance characteristics, especially fluidity. The oil does not lose its performance properties even at temperatures down to -40 ° C. This hypoid oil extends the life of the units by protecting the parts from corrosion and wear.

If you want to reduce the noise of the gearbox and get good protection against scuffing, you can buy ZIC G-F TOP hypoid fluid. The oil easily tolerates even severe operating loads and has a wide temperature range.

The hypoid gear (gear) transmission differs from the usual one, with straight or oblique teeth, in that its teeth are curved. They are bent along a special geometric curve - a hyperboloid, which can be seen in the figure. Hence the name: hypoid - short for.

There are two main features of the hypoid transmission. Firstly, it can only be used in nodes with intersecting gear axes. There is no point in trying to build a hypoid gear with parallel shafts: it will immediately jam.

Secondly, the axes of the shafts must be additionally offset relative to each other, otherwise jamming again. The amount of displacement must be exactly matched with the mathematical parameters of the hypoid, this is the so-called hypoid displacement.

Benefits of Hypoid Gear

For the first time in the automotive industry, a hypoid final drive was used by engineers of the American company Packard in 1926. What did it give?

The main gear transmits torque from the propeller shaft to the differential of the drive wheels. It is always carried out with a reduction in order to match the engine speed with the required ones for the wheels and at the same time increase the torque on them.

First, the propeller shaft has moved down by the amount of hypoid displacement. This made it possible to reduce the height of its tunnel in the cabin and at the same time to lower the center of gravity of the car, thereby improving its stability.

Second, the hypoid transmission transmits the moment more smoothly than the helical gear, not to mention. Finally, the hypoid transmission is less noisy and can transmit more torque than a conventional transmission. As the engineers say, it has a high load capacity.

All this, taken together, increases both the comfort of the car and its durability. Therefore, the hypoid final drive is an indispensable attribute of cars of a fairly high class, such as, for example, the Lexus "Infinity".

Her disadvantages

However, the hypoid transmission also has significant drawbacks, in addition to the complexity of manufacture and, accordingly, high cost. When the gears rotate, due to the fact that the teeth are bent, a force acting along the axis of the small, driving gear. As a result, the hypoid gear is very sensitive to wear, the workmanship of not only gears, but also all its parts, especially bearings. If it is inaccurately adjusted, it easily jams, especially when changing the direction of rotation, when engaging in reverse.

Every cloud has a silver lining: the propensity of the hypoid transmission to wedge is used in the center (center) limited slip differentials of the Thorsen type. They are used in vehicles with full automatic drive (4WD).

The teeth of the hypoid gear adhere to each other more tightly than the conventional gear, so it is also very contaminated in the oil. Only special hypoid oil with antiwear and extreme pressure additives should be poured into the crankcase of the hypoid gear. Moreover, you need to fill in a strictly defined amount.

Current use of hypoid transmission

However, all the disadvantages of the "hypoid" are more than offset by its advantages, and technologically they are quite surmountable. With the development of the automotive industry and the general culture of production, the "hypoid" was also transferred to the transmission of consumer-class cars. Nowadays it can already be seen in budget Chinese cars.

A lot of motorists are interested in the question: what is hypoid oil, what is its difference from an ordinary transmission oil? If you look at the hypoid composition, you can find a mixture of used and substandard oil that is suitable for steering gears, as well as some transmission units.

To improve the quality of such lubricants carry out a slight modification. Special additives are added to the composition, thanks to which the hypoid lubricant receives excellent extreme pressure characteristics.

These transmission fluids are classified as GL-5. They can be used in the transmission of vehicles equipped with hypoid drive axles. Such lubricating mixtures are widely used in helicopter gearboxes and car cardan shafts.

Specifications

For hypoid mechanisms to work properly, they must be lubricated with a component that contains approximately 4% sulfur. It protects metals from seizing, however, it leads to rapid oxidation. To neutralize this process, unique additives are added.

MOLYVAN L improves protective properties lubrication when parts are exposed to increased contact loads. This property of the additive made it possible to use it in gearboxes equipped with hypoid gears as protection against increased wear. In transmission fluids, the concentration of this additive sometimes exceeds 5%. The grease does not freeze at minus 30.

Time does not stand still. Today, many new modifications of oils have appeared for operation in high-speed hypoid mechanisms. The VIR-1 additive contains both phosphorus and sulfur. This allows you to add it to the most different types transmission oils. Tests have shown that it improves the quality of lubricating mixtures designed to improve the performance of a hyperboloid gear train.

All vehicles with hypoid gearboxes usually use multigrade grease that shows excellent results in temperate climates. Hypoid motor oils help to reduce wear on the surface of the part. In principle, their properties are not much different from those of conventional transmission ones, the only difference is the viscosity coefficient.

What oils can be used in hypoid gears

V modern cars gearboxes with hyperboloid gears must be installed. Almost all car owners are familiar with the TAD-17 grease. It is constantly poured into the transmission of domestic cars. After the appearance of foreign cars in Russia, the list of transmission fluids began to grow rapidly.

The main characteristic of such motor oils is their viscosity. Today, domestic manufacturers Supplies started using SAE classification used in the modern world. It includes several viscosity groups:

1. Summer - 3.
2. Winter - 4.

To distinguish winter oils from summer, the letter W is added to their name, for example:

• SAE70W,
• SAE75W,
• SAE80W.

For summer formulations, this letter is absent: SAE90, SAE140, SAE250. Seasonal options are designed for long-term use, but at the end of a certain period they have to be changed, although the resource is not completely exhausted. Therefore, their use is considered unprofitable. Today, all-season ones have become more popular, the designation of which has a double marking - SAE80W-90.

According to the API standard, gear oils are divided into classes depending on their performance (GL 1-6). The number of additives contained in them, which improve the operation of the gearbox, depends on the value of the figure.

For passenger cars equipped with a hyperboloid screw drive, GL-4/5/6 gear oils are used.

A car is a technically complex product. If you look closely at its design, then almost everywhere, one way or another, there is a change in the value of the torque. And this is not surprising, because it is he who comes from the engine to the wheels of the car. To transform it, both in size and direction, a variety of nodes are used, some of them use a hypoid transmission.

What and how changes

The transition of the moment from one node to another occurs with the help of special elements - shafts and gears. The shape of their teeth meshing with each other can be varied:

• cylindrical;
• conical;
• hypoid (short for hyperboloid), etc.

The latter is shown in the figure:

The number of teeth on different gears may differ and they may be positioned differently in relation to each other. Due to this, there is a change in the magnitude of the transmitted torque, both in direction and in magnitude. A device that performs such an action is called a gearbox.

Hypoid gear reducer

In fact, with the help of a gearbox in a car, all changes in the force transmitted from the engine to the wheels occur. The same gearbox is a gearbox in which, due to the connection of different pairs of gears with a different number of teeth, the magnitude of the force changes in different ways. Another element where there is a change in the direction and magnitude of the moment, it is necessary to consider the hypoid final drive (GP).

Just as a reminder - the GP is designed to change the direction of propagation of torque (from axial to perpendicular) on the car, as well as change its magnitude. It can be performed on any type of gear, but in modern cars usually a hypoid gear is used, which is part of the rear axle gearbox.


Why is this transmission applied to him? This is due to its inherent features, among which it should be noted:

1. smaller dimensions with the same characteristics in relation to other types of gears that can be used in the design of such a gearbox;
2. reduced load applied to one tooth, which ensures reliable operation of the gears, and also allows them to transfer more load and serve for a longer time;
3. lower noise level due to the fact that several teeth are in mesh at the same time;
4. the possibility of lowering the center of mass of the car due to the fact that the GP is performed with an offset.

However, it is worth noting the disadvantages that are possible in a gearbox that uses a hypoid transmission. These include the increased likelihood of seizing due to sliding along the line of contact. To reduce this, during manufacture, hypoid gears undergo special processing. In order to avoid such troubles, drivers should use only special grades of oil - transmission oil.

The use of hypoid gears in the GPU, in modern passenger car, has become a common practice. The rejection of gears of any other type when constructing such a unit is due to the advantages that the use of such gears provides.