EP4643029A1

EP4643029A1 - Locking differential with centrifugal clutch

Info

Publication number: EP4643029A1
Application number: EP23851036.6A
Authority: EP
Inventors: Lukás Pástor
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-12-27
Filing date: 2023-12-27
Publication date: 2025-11-05
Also published as: SK9887Y1; WO2024141942A1; SK1772022U1

Abstract

An overdrive gear mechanism (3) is connected between the cage (31) and the first output shaft (33) and/or the second output shaft (34). The output of the gear mechanism (2) carries a friction centrifugal clutch (1) which connects the output of the gear mechanism (2) with the cage (31), whereby the centrifugal clutch is designed for clutching when its revolutions increase. The gear mechanism (2) is formed by an epicyclic gearing and/or a strain wave gearing and/or a cycloid gear, and its gear ratio is at least 10:1, preferably at least 20:1, especially preferably at least 40:1. The revolutions of the cage (31) at the maximum speed of the vehicle are less than revolutions X of the clutching of the centrifugal clutch (1). During the turning of the vehicle at the minimal radius of the turning, it holds that n1 – n2 < X/i, where X are the limit revolutions of the clutching of the centrifugal clutch (1), i is the gear ratio of the gear mechanism (2). In a preferable arrangement, the gear mechanism (2) includes two speed gears ordered one after another with epicyclic gears.

Description

LOCKING DIFFERENTIAL WITH CENTRIFUGAL CLUTCH

Field of technology

The invention concerns a differential lock which is activated in the normal way during the propulsion of the motor vehicles on the basis of difference in revolutions of the output shafts. The lock does not require any electronic or electric control, and neither does it need hydraulic or pneumatic elements.

Prior state of the art

Various clutches controlled mechanically, electrically, pneumatically or hydraulically are used in order to lock the differential, that is, block the different rotation of two output shafts of the differential, by the order of the driver (chauffer).

Arrangements are known which ensure automatic blocking of different rotation of the output shafts on the basis of achieved difference in revolutions. Such self-locking differentials’ disadvantage is mainly during the rotation of the vehicle in small radius, where the parasitic torques arise, which worsen the dynamics of rotation. Such a differential clutch is preferable, which does not interfere into differential effect in all radiuses of the vehicle’s rotation, that is, the clutch does not block equal-torque balancing and, on contrary, it starts to block the differential function during drive slip.

Publication GB2193793A discloses inter-axle differential which includes friction multiplate clutch, where the pressure of the plates against each other is ensured by a pair of pins which are rotated by centrifugally-driven toothed segments. Such solution is complicated and, at the same time, the closing of the differential leads to increase the speed without drive slip of the front or rear output shaft.

Inter-axle differential pursuant to JPS61207220A discloses a centrifugal clutch which brakes the satellites driver in such a way that it connects it with the solid part of the axle drive box. Similarly, the centrifugal clutch is used to brake the satellites driver in the axle drive in order to connect the rear axle pursuant to EP0236695A1 . Satellites driver rotates pursuant to the difference in the revolutions of the front and rear drive, and the centrifugal clutch must be able to carry a relatively high torque, which increases its dimensions and decreases the reliability and durability.

The disadvantage of the known use of the centrifugal clutch to block the second level of the differential freedom is that the centrifugal clutch rotates not only during drive slip, but it rotates together with the cage even at identical revolutions of the two output shafts and during higher speed.

A desired mechanical type of the differential, which is not electronically, hydraulically or pneumatically controlled, cannot operate by itself as a 100% open and, at the same time, transfer sufficient amount of torque from the differential cage to both output shafts regardless of the load of the individual output shafts. This means, in practice, that the current state of the art does not allow for differential that is not controlled in the vehicle, and that would allow for easy turning of the vehicle, that is, for different rotations of the left and right wheel, and at the same time transfer sufficient amount of torque to one of the wheels in case the other wheel is not in contact with the road, or that its traction is minimal. Such simple solution of the lock with small number of components and high reliability is desired but not known.

Essence of the invention

The abovementioned deficiencies are significantly remedied by a differential lock with centrifugal clutch, where the differential includes a propelled cage, first output shaft and second output shaft, where a offset (balancing) toothed gear is present in the cage, whereby the gear transfers the torque led to the cage onto both output shafts, whereby the cage and both output shafts have the same axis of rotation, according to this invention, whose essence lies in the fact that between the cage and the first output shaft there is an overdrive (step-up) gear mechanism connected, and the output of this gear mechanism carries a centrifugal friction clutch which connects the gear mechanism with the cage, whereby the centrifugal clutch is designed for clutching when the revolutions increase.

Connecting the first output shaft with the cage causes blocking of the second level of differential freedom. Offsetting the revolutions of the first output shaft with the cage causes limitation of rotation of the offset toothed gear inside the cage, which decreases the difference in revolutions between the cage and the second output shaft. It thus suffices if the gear mechanism with a single centrifugal clutch was placed on a single side of the cage.

The adjectives “first” and “second” are only for clearer distinction between the output shafts, they do not indicate hierarchy or different functionality and they are interchangeable in this text. The first output shaft and the second output shaft can also be called left output shaft and right output shaft or vice versa if we speak of an axle differential, or they can be called front output shaft and rear output shaft or vice versa, if we speak of inter-axle differential.

The gear mechanism denotes a gear, gear machine connected to the cage in such a way that the difference between the revolutions of the cage and the revolutions of the first output shaft leads to several times faster rotation of the output of the gear mechanism. The overdrive gear will have typical gear ratio of at least 10:1 , preferably at least 20:1 , especially preferably at least 40:1. The overdrive gear is constructed in such a way that the centrifugal clutch is placed on its output, that is, in the gear member which has the highest relative revolutions vis-a-vis the engine drum. The drum is connected with the cage or the second output shaft. Within the disc of the centrifugal clutch and the drum of the centrifugal clutch the relative revolution increases which is the multiple of the difference of the revolutions of the cage and the output shaft, or multiple of the difference of the revolutions between the first and second output shaft. The difference in the revolutions manifests itself multiply in the difference between the rotations of the disc and the drum of the centrifugal clutch. The gear mechanism multiplies the difference of the revolutions, it increases the sensitivity of the mechanism, decreases the torque load of the centrifugal clutch, and the centrifugal clutch subsequently limits this difference in revolutions. The multiplication of the difference of the revolutions achieves the postponement of the point when the rotation of the centrifugal clutch together with the whole mechanism (without difference of the revolutions of the output shafts) leads to clutching of the centrifugal clutch. Were the gear mechanism not used, the clutching of the clutch would have taken place even during straightforward ride without drive slip, or the clutching during the drive slip would require very high difference in revolutions.

It is preferable if the gear mechanism has central arrangement around the cage’s axis so that the centrifugal clutch is simply placed within the cage’s axis. The gear mechanism is preferably epicyclic (planetary) gearing or strain wave (harmonic) gearing or cycloid gear with the respective gear ratio. In case of epicyclic gearing, it is advantageous to include two speed gears which even in small space by the side of the cage can ensure the required high overdrive gear ratio.

The term “centrifugal clutch” denotes any mechanical element for rotational connection of the shaft with the drum, whereby the connection uses the pressure of friction segments onto the inner surface of the drum, whereby the pressure of the frictions segments is derived from the centrifugal force. The friction segments, for example, plates, are placed on the shaft or the disc in such a way that they transfer the torque. The centrifugal clutch is adjusted for clutching when its revolutions increase. That means that at zero rotation the centrifugal clutch is open, the shaft is not rotationally connected with the drum. In this position the friction segments can be withdrawn from the surface of the drum by means of springs. When the revolutions increase, the centrifugal force overcomes the spring force and the friction segments transfer the torque from the shaft or the disc which carries the segments, respectively, onto the drum.

The term “differential” in this text denotes a gear mechanism with two levels of freedom which distributes the revolutions to two output shafts on the basis of the same torque or on the basis of basically the same torque, respectively. The lock of the differential according to this invention can be used for any type of mechanical differential. The differential can be conical, or the differential can be front with outer or inner cage. The construction of the differential itself is not important for the use of the lock according to this invention.

The differential lock according to this invention blocks one level of freedom or, once the set difference of revolutions of derived two output shafts is achieved, blocks one level of freedom at least partially, respectively, and thereby decreases the difference in the revolutions of the output shafts.

The basic principle of the invention lies in the mechanical multiplication of the difference of the revolutions of the first and second output shaft by means of a gear mechanism, whereby the output of this gear mechanism carries the centrifugal clutch, which connects the first and second output after the ramp up revolutions are achieved.

The previous description disclosed the connection of the first output shaft with the cage which causes the connection with the second output shaft, too. A construction is possible, too, where the first and second output shafts are connected directly with the gear mechanism and the centrifugal clutch. One of such arrangements transfers the rotation of the second output shaft through the hollow output from the cage on the side of the first output shaft by means of a connecting shaft which runs through the centre of the cage. The gear mechanism between first and second output shaft is in overdrive arranged in such a way that the output of the gear mechanism carries the disc of the centrifugal clutch and the drum of the centrifugal clutch is connected with the first output shaft. This increases the sensitivity of the lock since the difference in the revolutions between the output shafts is two times more than between a single output shaft the cage. The proposed gear ratio can be lower, or even half, compared to the solution with the gear between the cage and the output shaft.

In another arrangement, the rotation of the first and second output shaft can be led outside the cage and the mechanical comparison of the revolutions by means of a gear mechanism takes place basically externally, outside the differential. With such external leading of rotation of the output shafts outside the differential box, the lock according to this invention can be installed even subsequently into the existing propulsion constructions.

The differential lock with centrifugal clutch according to this invention is a self-acting mechanism which, thanks to the overdrive gear and the centrifugal clutch, allows for two output shafts to rotate in the same direction, whereby it allows for only some maximum difference in the number of revolutions of individual shafts. When the maximum difference in the number of revolutions is surpassed, the shafts are mechanically connected by means of a centrifugal friction clutch. The resulting friction of the centrifugal clutch ensures the transfer of the torque between the first output shaft and the cage, and subsequently between the cage and the second output shaft, which decreases the difference in the number of revolutions of the output shafts. Constructionally set number of revolutions when the centrifugal clutch starts to act is preferably higher than the number of revolutions of the differential cage at the maximal speed of the vehicle. This ensures the inactivity of the lock during the drive without drive slip; the centrifugal clutch does not achieve the revolutions necessary for the transfer of the torque, and the differential behaves as fully open.

During the drive slip of any wheel, the output of the gear mechanism starts to rotate which increases the revolutions of the centrifugal clutch and causes the transfer of the torque from the first output shaft onto the cage and thereby also onto the wheel with better traction. The larger the drive slip, the higher the revolutions are achieved by the centrifugal clutch, and the more of a torque is transferred. The gear ratio of the epicyclic gearing of 40:1 allows, for example, for unimpeded turning of the vehicle and, at the same time, full transfer of the power onto the wheel with better traction. The transition between fully open and fully closed (locked) differential is instant, and unimpeded even with full load, and it is dependent on the difference in number of revolutions of the left and right wheel or, eventually, difference in revolutions of the front and rear axle. The differential lock with centrifugal clutch according to this invention is self-acting in both directions of the drive, even during braking by engine.

The centrifugal clutch is preferably designed in such a way that the revolutions of the cage at the maximal speed of the vehicle n1 = n2 will not lead to the clutching of the clutch, whereby n1 are revolutions of the first output shaft, and n2 are revolutions of the second output shaft. In common cases, revolutions n1 , n2 are the same as the revolutions of the respective wheel. In case of the use of the gears in the wheels (such as in off-road vehicles, for example), there is known gear ratio between the revolutions of the wheel and the cage, or between the revolutions of the output shafts, respectively.

The stated rule during the straight drive is n1 = n2 < X, where X are limit revolutions of the clutching of the centrifugal clutch, but this rule needs not to hold entirely, since during the maximal speed the vehicle only drives straight or it turns the bend with large radius, and therefore the eventual blocking of the function of the differential is not problematic, and it can lead, on the contrary, to the stabilizing of the direction of the drive. For fast vehicles, it can hold that n1 = n2 < kX, where k coefficient mirrors the relationship of the maximal speed of the turning of the vehicle, and maximal construction speed. For example, for tractors, coefficient k will be close to 1 ,0; for cars, it can range from 0,5 to 0,75.

It is, however, preferable if it always holds that during the turning with the minimal turning radius (according to Ackermann axle geometry) there is no clutching of the centrifugal clutch. In such limit turning one expects relatively high speed of movement. Such situation can be expressed in this way: n1 > n2; n1 - n2 < X/I, where X are limit revolutions of the clutching of the centrifugal clutch and i is gear ratio of the gear mechanism on whose output the centrifugal clutch is placed.

These two rules lead to a choice of gear ration and setting of the limit of X revolutions of the clutching of the centrifugal clutch. Beyond X limit, there is gradual transfer of the torque between the first output shaft and the cage of the differential or the second output shaft. The activation of the lock is defined by a condition: n1 - n2 = X/i. In case of drive slip, it will hold that n1 - n2 > X/i or n2 - n1 > X/i. For these relationships to hold for the arrangement output shaft I cage or even for arrangement first output shaft I second output shaft, it is necessary that one can consider the gear ratio of the whole gear (gearing, gearbox) as a gear ratio - that is, together with the speed gear within the differential cage.

Since after the clutching of the centrifugal clutch there is balancing of the revolutions of the first and second output shaft, the difference (n1 - n2) i can decrease, which leads to opening of the centrifugal clutch. In order to stabilize the oscillation of n1 - n2 difference, it is preferable if the centrifugal clutch has a clutching and opening hysteresis. This can be achieved by a non-linear effect of the friction segments and/or springs or also by mass (weight) inertia of friction segments.

The advantage of the invention is its simple and reliable construction with long durability which does not require any electronic or electric elements or control units or switches or action members. The choice of the gear ratio of overdrive gear mechanism and setting of the centrifugal clutch design the lock into particular revolutions ratios of a mean of transport.

Description of drawings

The invention is further disclosed by means of figures 1 to 6. The depicted differential type, the gear ratio of the two-gear epicyclic gearing, the scale of depiction, are only examples and cannot be interpreted as limiting the scope of protection. For the purposes of clarity, the teeth are not depicted on the cage, and no connection of the cage with the propulsion, for example, with the gear, is depicted. The type of bearings is also only illustratory; these are depicted as rolling ball bearings even in cases when the bearings are supposed to capture torque reactions.

Figure 1 depicts the lock of the differential with the centrifugal clutch in combination with the conical differential; the plates of the centrifugal clutch do not touch the drum of the centrifugal clutch.

Figure 2 depicts the activated differential lock from the figure 1 , whereby in the active state the plates of the centrifugal clutch touch the drum of the centrifugal clutch.

Figure 3 depicts the differential lock with two centrifugal clutches for the attachable propulsion of the axle without the use of the standard differential.

Figures 4a, 4b, 4c schematically depict three basic states of the lock. Figure 4a shows the state during straightforward drive at maximum speed, whereby the friction segment of the centrifugal clutch does not transfer the torque to the drum. Figure 4b depicts the vehicle during turning at the minimal turning radius, where the friction segment of the centrifugal clutch does not transfer the torque to the drum. Finally, figure 4x depicts drive slip of the left wheel where the revolutions difference (n1 - n2) surpasses the limit X/l, which activates the centrifugal clutch. On figures 4a, 4n, 4c, the centrifugal clutch is depicted in the simplified way with two friction segments, whereby the gaps between plates and the drum are increased on these figures. On figure 4c, the drive slip of the left wheel is depicted, whereby previously the wheel has realized shorter path on the figure 4b, but in the figure 4b this did not lead to the activation of the lock. The speed is depicted by an arrow v on the figure 4c, and it can also mean stopping of the vehicle (v=0), where the surface without adhesion is depicted below the left wheel.

Figure 5 is a graph of clutching of the centrifugal clutch, where the point X denotes the clutching revolutions of the centrifugal clutch, M (Nm) is a transferred torque, axis x depicts revolutions per minute n (/min).

Figure 6 is an arrangement where the gear mechanism is placed between the first and the second output shaft. The figure is an axial cross-section of the differential cage with the hollow output from the cage; the connecting shaft runs through the cavity.

Examples of realization

Example 1

A differential lock with the centrifugal clutch according to figures 1 , 2, 4 and 5 is formed by a differential 3 cage 31 which is fixedly connected with a drum 13 of the centrifugal clutch 1. and the crown gear 21 which works with (is in the grip with) the middle cogwheel (gear) 25, which works with the smaller cogwheel 232, which is fixedly connected with a larger cogwheel 231 which works with the central cogwheel 22, which is fixedly connected with the disc IT The plates 12 of the centrifugal clutch 1. are rotationally placed in the disc 11., whereby the satellite gear assembly 23 formed by larger cogwheel 231 and smaller cogwheel 232 are placed rotationally in the driver (carrier) 24 of the cogwheels of the satellite gear assembly 23, and the middle cogwheel 25 is also rotationally placed in the driver 24, whereby the driver 24 is fixedly connected with the second output shaft 34 of the differential 3 and the disc 11 is rotationally placed in a single axis with the second output shaft 34, which works with the satellite wheel 32 and this works with the first output shaft 33 of the differential 3, whereby the satellite wheel 32 is rotationally placed in the differential 3 cage 31 . Values for use in a car:

Revolutions of the differential 3 cage 31 at the maximum car speed are 1600 rpm.

Revolutions of the centrifugal plate clutch 1. where the plates 12 enter into the contact with the drum 13 of the centrifugal clutch 1_ and torque is transferred from the disc 11 to the drum 13 are, approximately 2000 rpm.

Maximal difference in the number of revolutions of the differential 3 cage 31 and one of the car’s wheels, which can be achieved when driving in the bend without a drive slip, is 35 rpm.

Gear ration of the two-gear epicyclic ger mechanism 2 which increases the revolutions of the centrifugal clutch 1. is 40:1 .

Second (left) output shaft 34 is connected with the car’s left wheel.

First (right) output shaft 33 is connected with the car’s right wheel.

During the straightforward drive, the left and the right wheel have the exact same number of revolutions, and there is thus no increase of revolutions of the centrifugal clutch 1. compared to the revolutions of the cage 31 , which is at maximum 1600 rpm, so it cannot transfer any torque onto the drum 13 of the centrifugal clutch 1_, and the differential 3 behaves as fully open. The cage’s 31 revolutions at the maximum construction speed of the car can be used as a limit to set the onset of operation.

During the drive in the bend with radius of 6 meters with the front wheels fully turned, the differential 3 cage 31 revolves, at the speed of approximately 27 kmph, at 224 rpm, and at the same time the difference in the number of revolutions of one of the wheels and the differential 3 cage 31 is 35 rpm, which causes the increase in the revolutions of the plate clutch 1_ by approximately 1400 rpm to 1624 rpm overall. The plates 12 do not yet touch the centrifugal clutch’s 1. drum 13 and the vehicle turns without being limited by the differential 3 locking, that is, the lock is not yet active.

If, for example, at speed of 6 kmph one of the wheels loses traction completely, the differential 3 cage 31 has 59 rpm; the wheel with better traction stops to revolve and the wheel without the traction is rotated by the differential to 118 rpm. The difference between the revolutions of differential 3 cage 31 and the wheel without the traction is 59 rpm, which causes the increase in the revolutions of the plate clutch 1. by 2360 pm. The centrifugal clutch 1_ with plates 12 surpasses the limit of 2000 rpm, the plates 12 are pushed by the centrifugal force onto the drum 13 of the centrifugal clutch 1. and the resulting friction decreases, through the epicyclic gearing 2, the difference in the revolutions of the differential 3 cage 31 and the revolutions of the second output shaft 34 (on the left side), whereby the wheel with better traction is rotated through the differential 3.

If it is the left wheel which slips, the plate clutch 1. slows down the second output shaft 34 through the epicyclic gearing 2 and speeds up the first output shaft 33 through the differential 3, since the revolutions of the cage 31 are constant. If it is the right wheel which slips, the plate clutch 1 speeds up the second output shaft 34 through the epicyclic gearing 2 and slows down the first output shaft 33 through the differential 3.

When both wheels gain traction, the difference in the revolutions of the left wheel and the right wheel returns below the constructionally set value of the lock, the revolutions of the plate clutch 1. decrease, the differential 3 is gradually unlocked and it behaves as open. At each future drive slip of one of the wheels, the locking of the differential 3 automatically gradually increases and decreases pursuant to the size of the drive slip.

Example 2

Two automatic differential locks with the centrifugal clutch can be used in a single construction according to the figure 3 for the attachable propulsion of an axle without the use of the standard differential. In such case, the cage 31 is connected with the output of the gear of the vehicle and the second output shaft 34 propels the vehicle’s left wheel. The vehicle’s right wheel is propelled by the first output shaft 33 of the second centrifugal clutch 1.. The torque is led onto the cage 31 .

During the drive without drive slip, the revolutions of all the vehicle’s wheels are identical or similar, and no torque is transferred to the wheels of the connected axle through the centrifugal clutches 1. from the vehicle’s gear; the wheels are only pushed, as in the case of unpropelled axle. When the drive slip happens to vehicles of the permanently propelled axle, the difference in the number of revolutions of each wheel of the propelled axle and the cage 31 increases, which increases the revolutions of the centrifugal clutches 1., and torque is transferred onto both wheels of the connected axle, whereby unimpeded turning of the vehicle is still possible since the gear ratio of the revolutions of the wheels of the connected axle and the output of the vehicle’s gear is not fixedly set, as is the case when the standard propulsion with the differential is used.

The lock in this case is not a direct component of the differential 3, that is, it does not block the second level of the differential’s freedom, but it individually connects right and left wheel, whereby the vehicle must also have a typically connected drive axle with permanent propulsion, which will be usually equipped by a differential. The pair of the centrifugal clutches connects the wheels into grip only after reaching the set difference in revolutions. The arrangement according to this example can also be called a system with the attachable propulsion of another axle. The system according to this invention can preferably substitute a system with connecting another axle by means of a freewheel without inter-axle differential (as known in the prior art), where another axle must be propelled with fewer revolutions so that the freewheel is activated only at the larger drive slip.

Example 3

In this example according to the figure 6 the gear mechanism is between the first output shaft 33 and the second output shaft 34. The cage’s 31 construction is common, with conical offset gear, but the output crown gear on the side of the first output shaft 33 is hollow and the connecting shaft 35 runs through the opening, connected with the second output shaft 34.

The connecting shaft 35 is connected with the central cogwheel of the two-gear epicyclic gear mechanism 2, on whose output there is a centrifugal clutch 1_. The friction segments of the centrifugal clutch 1 are placed adjacently to the inner circumference of the drum 13, whereby the drum 13 is fixedly connected with the output from the cage 31 and with the first output shaft 33. The lock functions similarly as in example 1 , but the difference in revolutions of the first and second output shaft 33, 34 is larger (basically double) during the drive slip as that between the output shaft 33, 34 and the cage 31 in the first example. This achieves higher sensitivity of the lock and allows one to use gear mechanism 2 with smaller overdrive gear. Industrial applicability

Industrial applicability is obvious. According to this invention it is possible to produce and use mechanically activated differential locks, mainly in various wheeled means of transport, such as cars, trucks, tractors, and so on.

List of symbols

1 - centrifugal clutch

11 - disc

12 - plates

13 - drum

2 - gear mechanism

21 - crown gear

22 - central cogwheel

23 - satellite gear assembly

232 - smaller cogwheel

231 - larger cogwheel

24 - driver of satellite gears

25 - middle cogwheel

3 - differential

31 - cage

32 - satellite wheel

33 - first output shaft

34 - second output shaft

35 - connecting shaft n1 - revolutions of the first output shaft n2 - revolutions of the second output shaft

X - revolutions of the clutching of the centrifugal clutch i - gear ratio of the gear mechanism v - forward speed of the vehicle vmax - maximal forward speed of the vehicle

Claims

PATE N T C LAI M S

1 . A differential lock with a centrifugal clutch, where a differential includes a propelled cage (31), a first output shaft (33) and a second output shaft (34), where an offset toothed gear is placed in the cage (31), whereby the offset toothed gear transfers a torque led to the cage (31) onto both output shafts (33, 34), whereby the cage (31) and both output shafts (33, 34) have a same axis of rotation, is characterized by the fact, that an overdrive gear mechanism (2) is placed between the cage (31) and the first output shaft (33) and/or the second output shaft (34), or the overdrive gear mechanism (2) is placed between the first output shaft (33) and the second output shaft (34), whereby an output of this gear mechanism (2) carries a friction centrifugal clutch (1) which connects the output of the gear mechanism (2) with the cage (31) or with the first or second output mechanism (33, 34), whereby the centrifugal clutch (1) is designed for clutching when its revolutions increase.

2 . The differential lock with the centrifugal clutch according to the claim 1 , is characterized by the fact, that the gear mechanism (2) has a gear ratio at least 10:1, preferably at least 20:1, especially preferably at least 40:1.

3 . The differential lock with the centrifugal clutch according to the claim 1 or 2, i s characterized by the fact, that the gear mechanism (2) has a central construction with a symmetry in the axis of the cage (31 ).

4 . The differential lock with the centrifugal clutch according to the claim 3, i s characterized by the fact, that the gear mechanism (2) is formed by an epicyclic gearing and/or a strain wave gearing and/or a cycloid gearing.

5 . The differential lock with the centrifugal clutch according to the claim 4, i s characterized by the fact, that the gear mechanism (2) includes two speed gears ordered one after another with epicyclic gears.

6 . The differential lock with the centrifugal clutch according to the claim 4, i s characterized by the fact, that a drum (13) of the centrifugal clutch (1) and a crown gear (21), which works with a middle cogwheel (25), which works with a smaller cogwheel (232), which is fixedly connected with a larger cogwheel (231), which works with a central cogwheel (22), which is fixedly connected with a disc (11) in which there are movably placed friction plates (12) of the centrifugal clutch (1), are fixedly connected to the cage (31), whereby a satellite gear assembly (23) formed by the larger cogwheel (231) and the smaller cogwheel (232) is rotationally placed in a driver (24) of the satellite gear assemblies (23), and the middle cogwheel (25) is placed in the driver (24), too, whereby the driver (24) is fixedly connected with the second output shaft (34), and the disc (11) is rotationally placed in the axis of the rotation of the differential (3) cage (31 ).

7 . The differential lock with the centrifugal clutch according to any of the claims 1 to 5, is characterized by the fact, that the gear mechanism (2) connects the first output shaft (33) with the second output shaft (34), and the centrifugal clutch (1) connects the output from the gear mechanism (2) with the drum (13) which is fixedly connected with the first or the second output shaft (33, 34).

8 . The differential lock with the centrifugal clutch according to the claim 7, i s characterized by the fact, that the gear mechanism (2) is placed on a side of the first output shaft (33), whereby the second output shaft (34) is connected with the gear mechanism (2) through a connecting shaft (35), preferably the connecting shaft (35) runs out of the cage (31 ) through a cavity in an output central cogwheel to which the drum (13) is connected.

9 . The differential lock with the centrifugal clutch according to any of the claims 1 to 8, is characterized by the fact, that revolutions of the cage (1) at a maximum speed of a vehicle are less than revolutions X of a clutching of the centrifugal clutch (1).

10 . The differential lock with the centrifugal clutch according to any of the claims 1 to 9, is characterized by the fact, that the revolutions of the cage (31) at the maximum speed of the vehicle are less than kX, where X are the revolutions of the clutching of the centrifugal clutch (1 ) and coefficient k ranges from 0,5 to 1,0.

1 1 . The differential lock with the centrifugal clutch according to any of the claims 1 to 10, is characterized by the fact, that during a turning of the vehicle at a minimal radius of the turning it holds that n1 - n2 < X/i, where X are the limit revolutions of the clutching of the centrifugal clutch (1), i is the gear ratio of the gear mechanism (2).

12 . The differential lock with the centrifugal clutch according to any of the claims 1 to 11, is characterized by the fact, that the centrifugal clutch (1 ) is a plate clutch.

13 . The differential lock with the centrifugal clutch according to the claim 12, i s characterized by the fact, that the centrifugal clutch (1 ) is a dry clutch.

14. The differential lock with the centrifugal clutch according to the claim 13, i s characterized by the fact, that the centrifugal clutch (1 ) is a wet clutch with a common filling for lubricating both the cage (31) and the offset toothed gear.