RU2706622C1 - Forcibly locked conical differential of vehicle (versions) - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: group of inventions relates to locking differentials. In the first version, differential has housing (1) and cover (3). In housing (1) there are half-axial straight-spaced conical first and second gears (4, 5) and satellites (6). In cover (3) on inner end surface annular groove is made, which forms open chamber (9), in which piston (10) in contact with first gear (4) is installed with possibility of its longitudinal movement together with gear (4). In housing (1) on inner end surface there is similar annular groove, in which piston (11) is installed with possibility of its movement together with gear (5). Chamber (9) by means of channel (12) made in cover (3) communicates with union (13) fixed on external end surface of cover (3). Sliding washers can be installed between pistons and semi-axial gears. In the second version of invention two pairs of satellites are installed, which are installed on cross-piece.

EFFECT: enabling the design simplification.

4 cl, 2 dwg

Description

The group of inventions relates to mechanical engineering, namely, to differential gears, and can be used in transmissions of vehicles. The first option reveals the design features of the two-satellite conical differential, the second option - the four-satellite conical differential.

Known conical free differential of a car VAZ 2121 [V.A. Vershigora, A.P. Ignatov et al. VAZ 2121, ed. The Third Rome, 1996, p. 34, Fig. 17]. This "classic" differential is designed to transmit torque from the main gear to the axles of the wheelset of the drive axle. It allows the driving wheels of the car to rotate at different speeds, which eliminates the slipping of one of the wheels when the car is turning or when driving on an uneven stretch of road, when the wheels pass a path of different lengths. The differential has semi-axial bevel gears mounted on the semi-axes, and satellites mounted on a common axis (pin) installed in the housing, which is attached to the driven main gear covering it. The differential case is integral and has a flange for installing the driven gear. To enable the installation of gears in the housing, two opposed windows are made. When the driving gear and the driven gear of the main gear rotate, the torque is transmitted to the axis of the satellites, then through the satellites to the semi-axial gears and the semi-axles.

When the car moves on a straight and even road, the drive wheels meet the same resistance and rotate with the same frequency. Satellites do not rotate around their axis, and the same torque is transmitted to both wheels. As soon as the conditions of movement change, for example, in a bend, one half-axis begins to rotate more slowly, since the wheel with which it is connected encounters more resistance. Satellites come into rotation around its axis, rolling around on a decelerating half-axis gear and increasing the frequency of rotation of the second half-axis. As a result, this wheel accelerates its rotation and goes a long way along the arc of the outer radius.

This design is easy to manufacture and works reliably, while the drive wheels are inextricably linked with the road. But, when one of the wheels is in the air or on ice, it is this wheel that is spinning, while the other, standing on a hard surface, stops - the car cannot move.

Known designs forcibly locked differentials, in which the elements that carry out the blocking, are built into the differential itself.

So, in patent RU 2548237 publ. 04/20/2015, a force-locked differential is described, which contains a housing, a cylindrical locking ring, two main satellites, as well as two semi-axial gears interacting with them. The housing is additionally equipped with two locking satellites on a common axis, which is cranked. The diameter of the blocking satellites is smaller than the diameter of the main satellites. The differential is equipped with a two-position lock. The means of transition from the "free rotation" to the "locked" mode is made in the form of an external brake for the locking ring. The external brake may be an electromagnetic block brake mounted on a fixed gear housing. The control is carried out by the driver, who from the control panel of the car enters the locking satellites into engagement with the main satellites by turning the locking ring.

The disadvantage of this design is that at the moment the lock is turned on, an impact load arises on the gears, as well as the inability to limit the load when blocking due to the lack of slippage, since the two gears are rigidly blocked by the third.

As a prototype of both variants of the invention, an improved design of the classic limited slip differential, equipped with an electro-hydraulic system, which is described in WO 2017/053421, publ. 09/21/2016. Satellites and semi-axial gears are installed in the detachable differential case, one of which is additionally connected to the differential case through a package of friction disks in a normally open state. The system is equipped with a differential blocking activation mechanism, which has a fitting for supplying the working fluid under the piston, which blocks the operation of the differential. If necessary, completely block the differential or block with a certain force, above which the package of friction discs begins to slip, allowing the semiaxial gear to rotate relative to the housing, a hydraulic fluid is transferred through the fitting from the hydraulic control unit through the fitting from the hydraulic control unit, which moves the piston through the plates slip and acts on the rods that compress the package of friction discs, closing the semi-axial gear from the gearbox by the differential, thereby blocking it.

The hydraulic control unit of this system consists of an engine connected to a hydraulic pump, an electric control valve and a hydraulic fluid pressure sensor, which allows you to quickly change the pressure in the hydraulic line of the differential blocking activation mechanism.

By controlling the pressure in the differential hydraulic line, you can quickly bring it from a free state to the full lock or partial lock mode, in which the friction discs slip, transmitting limited torque to the axis.

The advantage of this mechanism is the ability to control the torque of the transmission, distributing it in the right ratio between the wheels of one axis during the movement of the vehicle, which will positively affect its handling and throughput.

The disadvantages of the prototype include a large number of parts subject to wear - a package of friction discs, bushings and sliding washers, pressure rods. These parts are located in the final drive gearbox inside the case of the classic conical differential, which traditionally has a small diameter compared to the wheels of the vehicle. For this reason, the diameter of the differential friction discs cannot be significant, and the torque that is transmitted by the differential on the vehicle axles is greater than in any vehicle transmission element. The small size of the friction discs that transmit large torque will inevitably lead to their rapid wear, will require the use of special friction lubricants, which in turn cause accelerated wear of bearings and other parts of the main gear.

The basis of the invention is the task of creating a lockable differential based on the classic free differential, controlled, like the prototype, using a hydraulic system in the process of moving a vehicle. The technical result achieved is a simplification of the design of a forcibly locked differential and an increase in durability by reducing the number of parts subject to frictional wear.

The problem in the first embodiment of the invention (two-satellite design) is solved by the fact that the forcibly locked bevel differential of the vehicle incorporates a housing with a cover, semi-axial spur bevel gears are placed in the housing, a pair of satellites interacting with them, the axis of which is fixed in the holes, is installed between the gears corps. It differs from the prototype in that in the lid and in the housing on the inner end surfaces, an annular groove is made, each of which forms an open chamber. A piston in contact with one of the semiaxial gears is installed in each chamber with the possibility of its axial movement and force action on this semiaxial gear. At the same time, it is possible to counter-move the gears and block the differential. On the side surfaces of both pistons, annular grooves are made in which sealing rings are installed. The camera made in the lid, through the first channel communicates with the first fitting fixed on the outer surface of the lid, and the camera made in the housing, through the second channel communicates with the second fitting fixed on the outer surface of the housing. Both fittings are designed to be connected to a controlled fluid supply system.

The design can carry out the force action of the pistons on the semi-axial gears directly if the area of the working surface of the piston corresponds to the surface area of the end face of the gear. As a preferred alternative, a realization is possible when sliding washers are installed between the pistons and the semi-axial gears.

The task in the second embodiment of the invention (four-satellite design) is solved by the fact that the forcefully locked bevel differential of the vehicle incorporates a housing with a cover, semi-axial spur bevel gears are placed in the housing, and satellites interacting with them are installed between the gears. It differs from the prototype in that the differential contains two pairs of satellites mounted on the crosspiece, the lid and body are jointed along the plane of the geometric axes of the crosspiece. The crosspiece is installed in the holes formed by mating to each other grooves made on the counter-oriented open ends of the lid and the housing. Moreover, in the lid and in the housing on the inner end surfaces, an annular groove is made, each of which forms an open chamber. A piston in contact with one of the semiaxial gears is installed in each chamber with the possibility of its axial movement and force action on this semiaxial gear. At the same time, it is possible to counter-move the gears and block the differential. On the side surfaces of both pistons, annular grooves are made in which sealing rings are installed. The camera made in the lid, through the first channel communicates with the first fitting fixed on the outer surface of the lid, and the camera made in the housing, through the second channel, communicates with the second fitting fixed on the outer surface of the housing. Both fittings are designed to be connected to a controlled fluid supply system.

In order to better demonstrate the distinguishing features of the invention, as an example, not having any restrictive nature, the preferred embodiment is described below. An example implementation is illustrated by the Figures of the drawings, in which: FIG. 1 is an isometric view of a differential (according to a first embodiment of the invention) with a partial cut-out of a housing and a cover; FIG. 2 - differential according to the second embodiment, axial section.

Since the second embodiment of the invention practically repeats the first, except that it uses two pairs of satellites instead of one and the features of the formation of grooves for installing the axes of the satellites, in the following detailed example of implementation, the two-satellite differential of the VAZ 2121 is taken as the basis for the design.

The force-locked differential of the vehicle has a housing 1 with a flange and technological windows 2 (there is no window in the second embodiment of the invention), closed by a cover 3. Inside the housing 1, semi-axial spur bevel gears are installed: the first gear 4 (from the side of the cover 3) and the second gear 5, and the satellites interacting with them 6. The axis 7 of the satellites 6 is installed in the holes 8 made in the housing 1. An annular groove is made in the cover 3 on the inner end surface (end surface facing the inside of the housing) a, forming an open chamber 9, in which a piston 10 (a toroid of rectangular section) in contact with the first gear 4 is mounted with the possibility of its longitudinal (along the axis of the differential case) movement together with the first semi-axial gear 4. A similar annular ring is made on the inner end surface 1 of the housing 1 a groove forming a second open chamber (not shown in FIG. 1) in which a piston 11 is mounted (Fig. 1 is conventionally shown), with the possibility of its longitudinal movement (along the axis of the differential case) together with the second semi-axial gear 5. The chamber 9 through the channel 12, made in the cover 3, communicates with a fitting 13 mounted on the outer end surface of the cover 3, intended for connection to a controlled supply system of the working fluid. Similarly, the camera in the housing through the channel (not shown in Fig. 1) communicates with a fitting 14 mounted on the outer surface of the housing cover. On the lateral surfaces of the piston there are annular grooves in which the sealing rings 15 are mounted. The differential transmission fluid is used to block the differential into chambers 9 through fittings 13 and 14.

The system of controlled supply of working fluid to the differential is quite simple to implement, is not the subject of the invention, and therefore its drawing is not given.

This system consists of a hydraulic unit, which serves as a source of high-pressure hydraulic fluid, a hydraulic line and a special coupling for supplying hydraulic fluid to the differential rotating in the vehicle gearbox. The hydraulic unit is controlled by the on-board computer of the car.

When the differential is in free (unlocked) mode, the hydraulic unit does not create hydraulic fluid pressure in the hydraulic line attached to the differential.

At the signal of the on-board computer of the car, the hydraulic unit begins to create pressure in the hydraulic line connected to the differential. Under the influence of the hydrostatic pressure of the working fluid, which, through the fittings 13 and 14 and the channels, respectively, in the cover and in the housing, enters the chambers with installed pistons 10 and 11. Pistons 10 and 11 perform axial counter movement, acting on the corresponding semi-axial gears 4 and 5 eliminating the gap between the gears and the satellites interacting with them 6. Continuing the movement, the pistons 10 and 11 move the gears to their stop in the satellites 6. In this case, the pressure force of the pistons 10 and 11 during the interaction of the semi-axial gears 4 and 5 with the satellites 6 rizhimaet latest differential housing to radially and axially gear. As a result, the gears through the satellites are pressed against each other and the housing without a gap. Specialists know that the axial working clearance in a bevel gear necessary for the normal operation of the gears is 1 / 8m, where m is the gear tooth module. In reality, for automobile differentials, the axial clearance is 1-2 mm. The bevel gear jammed between the differential housing 1 and the pistons is jammed - the differential is locked.

The axis of rotation of the gears and the axis of the satellites in the bevel gear intersect at an angle of 90 °. The torques acting in the gear transmission cause interaction forces having circumferential, radial and axial components. After stopping the flow of working fluid into the chambers, the axial forces return the satellites 6, gears and pistons to their original state, thereby restoring the working clearances of the gear transmission. The gear is unlocked.

If, at the command of the on-board computer of the car, the piston chambers remain under a certain (set) pressure, the differential remains in limited lock mode. In this mode, the gears can come into rotation only after overcoming the pressure force of the pistons and pushing them back into the chamber by the size of the working gap. By changing the pressure in the chambers, you can change the magnitude of the torque under which the differential remains locked. The ability to control the torque transmitted by the differential on the axle of the vehicle while driving has a positive effect on the handling and throughput of the vehicle. Limiting the ultimate forces acting on the differential gears in blocking mode by limiting the maximum pressure in the hydraulic system protects the mechanism from breakdowns due to overload and increases its reliability.

In the example described above, the pistons and gears are in direct contact. However, if the contact area is insufficient, slip washers are additionally installed between the gears and pistons (not shown in Fig. 1).

Everything described above with respect to the two-satellite differential is also true for the four-satellite differential (the second embodiment of the invention is presented in Fig. 2). In FIG. 2, part of the positions repeats the numbering of the positions of FIG. 1: 1 - housing, 3 - cover, 4 - first gear, 5 - second gear, 6 - satellites, 9 - open chambers in the cover and body, 10, 11 - pistons, 12 - channels in the cover and body, 13 - fitting lids, 14 - body fitting, 15 - piston o-rings.

In the second embodiment of the invention, two pairs of satellites mounted on the crosspiece 16 are used (the crosspiece may be a combined one and include two mutually perpendicular axis of the satellites connected by a collapsible connection). Moreover, in the second embodiment of the invention, the lid and the body are jointed along the plane of the geometric axes of the cross, that is, the lid 3 forms a cavity commensurate with the volume of the body cup. The axis of the satellites (the cross) is installed in the holes formed by the mating grooves 17 made on the counter-oriented open ends of the lid and the housing, i.e. the mounting holes of the cross are formed by complementary grooves when the housing and the cover are articulated. In FIG. 2 shows an implementation in which sliding washers 18 are installed between the semi-axial gears and pistons. The differential operation according to the second embodiment of the invention shown in FIG. 2, is carried out similarly to the above with the difference that the action of the pistons on the semi-axial gears is carried out through the sliding washers 18. However, it is possible to implement without washers.

Thus, in the claimed force-locked differential (in both versions), blocking is carried out when the piston bevel gears are integrated in the differential design, which causes the gears to jam.

Created on a completely different principle of operation, the new differential contains the smallest possible number of parts and is maximally unified with serial conical differentials and can be used in any vehicles. The number of parts subject to frictional wear is minimized.

Claims (4)

1. Forced-locked conical differential of the vehicle, comprising a housing with a cover, semi-axial spur bevel gears are placed in the housing, a pair of satellites interacting with them is mounted between the gears, the axis of which is fixed in the openings of the housing, characterized in that in the cover and in the housing an annular groove is made on the inner end surfaces, each of which forms an open chamber, in each chamber a piston in contact with one of the semi-axial gears is installed with the possibility of its axial movement and force acting on this semi-axial gear, while it is possible to counter-move the gears and block the differential, annular grooves are made on the lateral surfaces of both pistons, in which the sealing rings are installed, while the chamber made in the lid communicates via the first channel with the first fitting fixed to the outer surface of the lid, and the camera, made in the housing, communicates with the second channel fixed to the outer erhnosti second fitting body, both fitting designed for connection to the system controlled the supply of hydraulic fluid. 2. Force-locked bevel differential according to claim 1, characterized in that sliding washers are installed between the pistons and the semi-axial gears. 3. Forced-locked conical differential of the vehicle, comprising a housing with a cover, semi-axial spur bevel gears are placed in the housing, satellites interacting with them are installed between the gears, characterized in that it contains two pairs of satellites mounted on the crosspiece, the joint of the cover and housing is carried out along the plane of the geometrical axes of the cross, the cross is installed in the holes formed by the mating grooves, made on the counter oriented open ends of the cover and the housing, while in the cover and in the housing on the inner end surfaces, an annular groove is made, each of which forms an open chamber, in each chamber there is a piston in contact with one of the semi-axial gears with the possibility of axial movement and force on this semi-axial gear, while it is possible to counter-move the gears and block the differential, annular grooves are made on the lateral surfaces of both pistons, in which O-rings are installed, with the chamber made in the lid communicating with the first fitting fixed to the outer surface of the lid, and the chamber made in the housing, through the second channel, communicating with the second fitting fixed to the outer surface of the housing, both fittings are designed for connections to a controlled fluid supply system. 4. Force-locked bevel differential according to claim 3, characterized in that sliding washers are installed between the pistons and the semi-axial gears.

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