RU162710U1 - INCREASED FRICTION DIFFERENTIAL - Google Patents

Abstract

1. The limited slip differential comprising a housing and a cover, a pair of semi-axial gears with supporting parts coaxially mounted in the housing and the cover rotatably and connected by splined openings with output shafts, two sets of satellites, each of the satellites engages with the corresponding semi-axial gear and satellite of another set, characterized in that the differential is equipped with two friction disk packs that are installed with the possibility of contact with the outer end parts of the satellites, moreover, friction discs corresponding packet is associated with the housing and the differential cover, and the other part of each package - with half-axial shesternyami.2. The differential according to claim 1, characterized in that a clip is installed in the differential housing with the possibility of movement, in the grooves of which are placed sets of satellites. 3. The differential according to claim 1, characterized in that each package of friction discs is equipped with a Belleville spring.

Description

The utility model relates to mechanical engineering and can be used as a differential installed in driving axles of vehicles.

Two types of self-locking differentials are known: those blocked from the difference in angular velocity of the wheels and those that are blocked from the difference in torque.

The first includes a differential with a viscous coupling, as well as the so-called electronic differential lock. The second type includes hypoid and disk differentials.

A well-known disc differential is a symmetric differential in which one or two friction disc packs are added. Some friction discs are rigidly connected to the differential case, the other part is connected to the axle shaft. The principle of operation of a limited-slip differential of a disk type is based on the friction force arising from the difference in the moments of rotation of the axle shafts. With rectilinear movement, the differential case and half-axis rotate at the same speed, the friction package rotates as a whole. With an increase in the rotational speed of one of the half-axes, the corresponding part of the disks in the packet begins to rotate faster. In this case, a friction force arises between the disks, which prevents an increase in the rotation frequency. The torque on the free wheel increases, thereby achieving a partial differential lock. The compression ratio of the friction discs can be fixed (implemented using springs of constant stiffness) or variable (carried out using a hydraulic drive, including electronically controlled).

Varieties of disc limited slip differentials are described in patents RU No. 37787, IPC 7 F16H 48/20, 2004, EP No. 1508466, IPC 7 V60K 17/35; BKK 23/08; B60K 28/16; B60K 41/24, 2005, WO No. 0236383, IPC 7 B60K 17/348; B60K 28/16, 2002, US No. 20066211532, IPC F16H 48/06 (2006.01), 2006, RU No. 2390433, IPC B60K 17/35 B60K 23/00 (2006.01), 2010, US No. 46667534 IPC 7 F16D 13/64; F16D 13/74; 1987 and others.

Their common drawback is that the disc limited slip differential has a relatively small initial moment adjustment range, a high blocking coefficient affects the smoothness of the differential at high loads, even full blocking is possible - all this makes it possible to use it on a regular car used on public roads, not always appropriate. This is especially true for the installation of self-locking differentials of this type in the front axle. In addition, there is a rapid wear of components.

Self-locking differentials with hypoid (worm or helical) and helical gearing are known.

The principle of operation is based on the property of a wedge of a hypoid or helical pair. In this regard, the main (or all) links in such differentials are helical or hypoid. Three main types can be distinguished.

Type 1 is manufactured by Zexel Torsen. Hypoid pairs are the gears of the leading axle shafts and satellites. Moreover, each half-axis has its own satellites, which are paired with the satellites of the opposite half-axis by conventional spur gearing. It should be noted that the satellite axis is perpendicular to the semi-axis. With normal movement and equality of torque transmitted on the half-axis, the hypoid satellite / pinion pairs are either stopped or cranked, providing a difference in the angular speeds of the half-axes in the rotation. As soon as one of the semiaxes starts to slip and the torque falls on it, the hypoid semiaxis / satellite pairs begin to rotate and wedge, creating friction with the differential cup and with each other, which leads to partial blocking of the differential. Due to the moment of friction, the differential redistributes the torque in favor of the lagging axle shaft. This design works in the largest range of torque distribution - from 2.5 / 1 to 5.0 / 1. The response range is governed by the angle of inclination of the worm teeth.

The author of the second type is the Englishman Rod Quaife. This differential uses helical gears of semiaxes and helical gears of satellites. The axes of the satellites are parallel to the semiaxes. Satellites are located in peculiar pockets of the differential cup. At the same time, paired satellites do not have spur gears, but form another hypoid pair, which, when wedged out, also participates in the blocking process. A similar device has the Tractech True Trac differential (see https://www.drive2.ru/I/4053239664633472574).

The company Zexel Torsen in its differential T-2 offered a slightly different layout in fact, the same device. Due to its unusual design, paired satellites are interconnected from the outside of the semi-axial gears. Compared to the first type, these differentials have a lower blocking coefficient, however, they are more sensitive to the difference in transmitted moment and work earlier (see http://www.meta-s.ru/product_2099.html).

When the differential is operating on the front axle of the car, an additional pushing force on the steering wheel can be created, which requires special care of the driver. Therefore, the design of such differentials contain a preload clutch, which provides a smooth operation of the lock. In the case of installing such a differential on the front axle, a steering wheel jerk is excluded, which is directly related to traffic safety.

A common disadvantage of hypoid differentials is the following:

- during operation, the preload falls, in order to restore it, it is necessary to change the adjusting washers, usually this happens after 20-40 thousand km, depending on the driving style;

- in case of non-compliance with routine maintenance, the system will work as a normal differential.

Hypoid (screw or worm) self-locking differentials are widely used both as interwheel and center differential.

Known anti-slip differential of the vehicle, comprising a hollow body, inside of which axle gears are mounted coaxially to each other and the gears are mounted parallel to the latter on the axes of the satellite, engaged with the axle gears to form gears with one of them with a negative gear, with the other with a positive gear ratio, in which the gears are self-locking, and the satellites and semi-axial gears are made with bevel or chevron teeth (for an analogue, see RF patent No. 2091644, IPC 6 F16H 48/28, 1997)

Disadvantage: it has insufficient smoothness of the differential, especially at high loads. The placement of semi-axial gears and satellites in a housing having an integral design reduces the service life of the device, since the axial runout of the nodes leads to the destruction of the housing.

A limited slip differential is known that comprises a housing with a central longitudinal hole in which the right and left semi-axial gears are located, separated by a stop element, satellites mounted in the housing with the possibility of gearing with semi-axial gears, and end caps of the housing with mounting bolts. In addition, sequentially alternating blind longitudinal holes are additionally made on the right and left end surfaces of the housing for free placement of the right and left rows of satellites in their cavities, the right row of satellites gearing with the right semiaxial gear, the left one, respectively, with the left, and the satellites from opposite rows have gearing and in pairs with each other (analogue - see patent for utility model of the Russian Federation No. 36131, IPC 7 F16H 48/28, B60K 17/16, 2004)

It has insufficient smoothness of the differential, especially at high loads. Placement of satellites and semi-axial gears in a one-piece housing, closed on both sides by end stop covers. As a result of axial runout of satellites and semi-axial gears, the housing becomes unusable, which, accordingly, reduces the service life of the product.

Known planetary limited slip differential, comprising a housing, a pair of sun gears with supporting parts, coaxially mounted in the housing with the possibility of rotation in it, and designed to connect splined holes with output shafts, two sets of satellites, each of which is engaged with the corresponding sun gear and two satellites of another set. Satellites of both sets are located in the housing sockets with the possibility of contact with their surfaces. A preload clutch is located between the sun gears, which includes a pair of thrust rings with disc springs located in them. The differential case is made of primary and secondary parts. Sun gears are located in the main and additional parts of the housing with the possibility of axial movement and abutment by the ends of their supporting parts to the ends of the central supporting nests of the housing parts (see utility model of the Russian Federation No. 25922, IPC 7 F16H 48/28, 2002). This decision was made as a prototype.

Disadvantages:

1. Has an insufficient range of smooth differential operation, especially at high loads.

2. The placement of semi-axial gears and satellites in a two-part housing reduces the service life of the device, since the axial runout of the nodes leads to the destruction of the housing.

The objective of the proposed solution is to create a design that combines the advantages of both types of limited slip differentials - disk and screw types, namely, optimization of the blocking coefficient, improving the smoothness of the differential at high loads.

The specified technical result is achieved due to the fact that in the limited slip differential, comprising a housing, a cover, a pair of semi-axial gears with supporting parts, coaxially mounted in the housing and the cover with the possibility of rotation, and connected by splined openings with output shafts, two sets of satellites, each of which engages with the corresponding semiaxial gear and a satellite of another set, in accordance with a utility model, the differential is equipped with packages of friction discs installed with the possibility of contact with the outer end parts of the satellites, with some of the friction discs of each package connected to the housing and differential cover, the other part of each package to the semi-axial gears.

In the differential housing with the ability to move, a clip is installed, in the grooves of which are placed sets of satellites.

Each friction disc pack is provided with a disc spring.

The technical result from the use of all the essential features of the utility model is to optimize the blocking coefficient, improve the smoothness of the differential at high loads and eliminate quickly wearing parts, which ultimately increases the life of the entire mechanism.

The presence of packages of friction discs installed in such a way that when there is a difference in moments on the drive wheels of the car, the corresponding satellites press the disks in the housing and differential cover, increasing the friction force between the disks. This interaction of the satellites and friction disks provides braking of the disks among themselves and additional transmission of torque from the housing or cover to the corresponding semi-axial gear, which drives the lagging wheel. Thus, the locking coefficient increases, the smoothness of the differential at high loads improves.

In addition, the presence of packages of friction discs with large disk springs due to the uniform distribution of internal friction over a larger contact area during differential operation eliminates rapidly wearing components from the differential design: preload couplings (splined rings and small disk springs), which, ultimately, extends the life of the entire mechanism

The presence of a movable cage, in which the satellites and partially semi-axial gears are located, allows for high accuracy of the location of the satellites and gears, and also increases the maintainability of the differential, allowing, if necessary, to replace the cage without replacing the case and differential cover.

The differential of the vehicle is illustrated by drawings.

FIG. 1 - general view - a longitudinal section of the differential;

FIG. 2 is a section AA in FIG. one;

FIG. 3 is a section BB of FIG. one;

FIG. 4 is a section BB of FIG. one;

FIG. 5 is a section G-D of FIG. one.

The differential of the vehicle (see Fig. 1) comprises a housing 1, a cover 2. In the housing 1, a semi-axial gear 3 of the output shaft is located, and in the cover 2 there is a half-axis gear 4 of the output shaft. The differential contains at least two sets of satellites. Satellites 5 of the housing set and satellites 6 of the cover set are installed in the grooves of the casing 7. Two packages of 8 friction disks, including disks 9, 10 with disk springs 11, are located on opposite sides inside the housing and the cover, respectively.

The disks 9 are provided with protrusions 12, which during assembly enter the grooves 13, machined on the outer surface of the corresponding semi-axial gear 3, 4.

On the disks 10, similar protrusions 14 are made, which enter the grooves 15 made on the inner surface of the housing 1 and the differential cover 2.

The differential of the vehicle is as follows. With the rectilinear movement of the machine, all the parts of the differential rotate as a unit. When turning the machine with increasing curvature of the trajectory, the torque remains constant, but the difference in the speeds of rotation of the wheels of the driving axis of the car increases. The semi-axial gear associated with the lagging wheel, for example 3, rotates slower than the housing and rotates the set of satellites 5 engaged with it. The satellites 5 transmit the rotation to the set of satellites 6, which engage with the satellites 5. Satellites 6, in turn, transmit the rotation to a semi-axial gear 4 and another vehicle wheel, which provides different angular speeds of the wheels. At the beginning of the slipping of one of the wheels of the driving axle of the car, a difference in torque appears between the wheels of this axis and inside the differential, due to which the internal gears 3, 4, satellites 5, 6 are wedged out and the friction discs 9, 10 of the packages 8 are pressed into the differential and then blocked differential

The differential uses helical gears of the semiaxes and cylindrical helical satellites. The axes of the satellites 5, 6 are parallel to the axes of the semi-axial gears 3, 4. The satellites 5, 6 are located in the grooves of the yoke 7, and the yoke 7 has the ability to move in the grooves of the housing 1. The paired satellites 5, 6 form a helical pair, which, wedging, so It is also involved in the blocking process. On the periphery of each semi-axial gear 3, 4 longitudinal grooves 13 are made, which engage with the protrusions 12 of the friction discs 9 of the corresponding friction package. On the inner surface of the differential housing 1 and the cover 2, similar longitudinal grooves 15 are made, which engage with the protrusions 14 of the friction disks 10 of the corresponding friction package. The disks 9 in contact with the semi-axial gears 3, 4 alternate with the disks 10, which engage with the housing 1 and the differential cover 2. The transmission of torque from the engine to the axle shafts occurs through the engagement of the satellites 5, 6 with the semi-axial gears 3, 4 and with each other. When the torque changes, the screw pairs of the satellites are wedged and pressed against the walls of the holes of the cage 7, and the ends of the satellites are pressed to the corresponding friction packs of the disks, pressing the disks 9, 10 against each other and increasing the friction in the differential. Thus, the differential redistributes the moment between the wheels towards the lagging wheel. The degree of pressure (blocking) depends on the amount of torque transmitted by the engine. Providing a lock during acceleration and braking, the differential of increased thorns works as usual in the absence of torque transmitted by the engine.

The inventive device can be used as a cross-axle and interaxle differentials on both front-wheel drive and rear-wheel and all-wheel drive vehicles.

The device can be manufactured in the factory using well-known materials and technologies.

Claims (3)

1. The limited slip differential comprising a housing and a cover, a pair of semi-axial gears with supporting parts coaxially mounted in the housing and the cover rotatably and connected by splined openings with output shafts, two sets of satellites, each of the satellites engages with the corresponding semi-axial gear and satellite of another set, characterized in that the differential is equipped with two friction disk packs that are installed with the possibility of contact with the outer end parts of the satellites, moreover, friction discs corresponding packet is associated with the housing and the differential cover, and the other part of each package - with the side gears. 2. The differential according to claim 1, characterized in that a clip is installed in the differential housing with the possibility of movement, in the grooves of which sets of satellites are placed. 3. The differential according to claim 1, characterized in that each package of friction discs is equipped with a Belleville spring.

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