CN1704273A

CN1704273A - Rear axle with electromagnetic clutch and gear differential mechanism

Info

Publication number: CN1704273A
Application number: CN 200410047493
Authority: CN
Inventors: W·R·小凯利
Original assignee: BorgWarner Inc
Current assignee: BorgWarner Inc
Priority date: 2004-05-28
Filing date: 2004-05-28
Publication date: 2005-12-07

Abstract

The invention relates to a rear axle common practice used in primary front wheel drive vehicle which comprises two electromagnetic clutches and a gear differential spider. First electromagnetic clutch provides force moment to gear differential spider which then provides drive force moment to the two axles. The gear differential spider includes second electromagnetic clutch which can be dearranged between the shell of gear differential spider and output axle. First electromagnetic clutch provides controlled force moment to rear differential gear; while second electromagnetic clutch gradually depresses the difference of gear differential spider.

Description

Back axle with magnetic clutch and gear differential mechanism

Technical field

The present invention relates generally to a kind of back axle assemble that is used for forward drive vehicle, relates more specifically to a kind of back axle assemble with two magnetic clutchs and a bevel gear diff.

Background technology

Traction control and Vehicle Stability System are important topics of current engineering developme.The software of many kinds of scheme utilization complexity come from for example four independently receive data the wheel speed sensor, can provide the power transfer clutch of variable torque transmission and brake application with control, thereby improve manipulation, braking and the control comprehensively of vehicle.

Mechanical power drive disk assembly and electronic type control system have been shown in the prior art fully.For example, U.S. Patent No. 5407024 has been introduced a kind of adaptive drive system, wherein the trailing wheel for vehicle provides moment of torsion consistently, and when detecting velocity contrast between the front and back wheel and surpass a variable thresholding, by the modulating clutch in the part-time case automatically and incremental ground provide moment of torsion for front-wheel.F-w-d vehicle also is combined with unique adaptive torque transmission and stabilitrak.In a kind of f-w-d system, the rear axle with a pair of power-transfer clutch can engage independently, so that provide moment of torsion for left and right trailing wheel.This system is disclosed in the U.S. Patent No. 6327935.

Obviously, need a kind of software that is used for the other and different power-transmitting part of four-wheel-type adaptive drive system and is combined with control policy.

Summary of the invention

The back axle assemble that is used for elementary forward drive vehicle comprises two magnetic clutchs and a gear differential mechanism.First magnetic clutch provides moment of torsion for gear differential mechanism, and gear differential mechanism provides driving torque for two axles again.Gear differential mechanism comprises second magnetic clutch, and it operationally is arranged between differential gear box and the output shaft.Actuating of first magnetic clutch to the back diff provides controlled (gradual) moment of torsion to apply, and actuating of second magnetic clutch little by little suppressed the differential of gear differential mechanism.Magnetic clutch can be actuated independently or be actuated together, and this just provides three kinds of different operation modes: (1) has only first clutch to be actuated, and it is operated as the 4Wdvehicle that has the back diff of connection; (2) have only second clutch to engage, rear axle is not driven, but does not have velocity contrast between the rear axle; And (3) two power-transfer clutchs all are actuated, and it is operated as having the differential 4Wdvehicle of no rear axle.Be appreciated that foregoing description is only for introduction and illustrative purposes and at the state that excites fully or actuate of power-transfer clutch.Because power-transfer clutch is the modulation system power-transfer clutch, so the proportion expression of power-transfer clutch or local joint can realize the optionally modulation level that the moment of torsion via first clutch transmits, and by second clutch is realized differential part is suppressed.

Therefore, an object of the present invention is to provide a kind of back axle assemble with two magnetic clutchs.

Another object of the present invention provides a kind of back axle assemble with two magnetic clutchs and a gear differential mechanism.

Another object of the present invention provides a kind of back axle assemble that is used for forward drive vehicle, its have can with torque controlled offer first magnetic clutch of gear differential mechanism, gear differential mechanism has second magnetic clutch, and it can controllably suppress the differential of diff.

By the following description and the accompanying drawing of reference preferred embodiment, can know other purpose of the present invention and advantage, similar in the accompanying drawings label is represented identical parts, element or feature.

Description of drawings

Fig. 1 is the scheme drawing according to the transmission system of the four-wheel drive car with the back axle assemble that has comprised two magnetic clutchs and a diff of the present invention;

Fig. 2 is the full sectional view according to back of the present invention axle assemble;

Fig. 3 is the local full sectional view according to the amplification of the first of back of the present invention axle assemble;

Fig. 4 is the local full sectional view according to the amplification of the second portion of back of the present invention axle assemble;

Fig. 5 is the part sectional view according to the amplification of the diff parts of back of the present invention axle assemble along Fig. 4 center line 5-5; With

Fig. 6 is the part sectional view of the amplification of the ball slideway mechanical arm according to magnetic clutch assembly of the present invention (ball ramp operator) along Fig. 4 center line 6-6.

The specific embodiment

Referring now to Fig. 1,, schematically illustrate the transmission system that has elementary f-w-d and combine four-wheel drive car of the present invention among the figure, it is with label 10 expressions.The transmission system 10 of automobile comprises driving engine 12, its link to each other with drive axle 14 and direct drive it.Drive axle 14 can be artificial or automatic drive axle, and can drive bevel gear or spiral bevel gear sets 16, gear cluster 16 can be elementary or prime power drive system 20 provides power, and power drive system 20 comprises prime or primary drive shaft 22, prime or elementary diff 24, a pair of driving front axle 26 and corresponding a pair of prime or elementary tire and vehicle wheel component 28.Should be appreciated that prime or elementary diff 24 are traditional.

Bevel gear or spiral bevel gear sets 16 also provide power for secondary or a back level power drive system 30, and power drive system 30 comprises secondary transmission shaft 32, back level or secondary bridges assembly 36 with suitable universal-joint 34, a pair of driving is secondary or rear axle 38 and corresponding a pair of secondary or back level tire and vehicle wheel component 42.

Controller or microprocessor 50 are associated with the transmission system 10 of automobile, and can be from a plurality of wheel speed sensors 52 received signal.Wheel speed sensor 52 preferably is used to anti-skid brake system (ABS), pull-in control system or the stabilitrak of vehicle that the wheel speed sensor of signal is provided simultaneously.Perhaps, they can be the sensor specials that only uses for microprocessor 50.This sensor 52 is preferably Hall transducer, yet they also can be variable-reluctance transducer, optical pickocff or similar device.

Controller or microprocessor 50 also can relevant sensor (not shown) and other vehicle operating situation be as the front tyre that sent by the vehicle driver and the reception information when the anterior angle position of vehicle wheel component 28 from the sensor 54 relevant with elementary or prime transmission shaft 22, with back level or secondary transmission shaft 32.Controller or microprocessor 50 include software, its can from sensor 52 and 54 and other vehicle sensors receive and processing signals, determine that correct action is with stability that improves vehicle and the control that keeps vehicle, and/or to skidding or other similar operations situation is corrected or compensated, and for the first magnetic clutch assembly 70 provides first output signal, the first magnetic clutch assembly 70 optionally offers the bevel gear diff and the second magnetic clutch assembly 190 with driving torque.

Referring now to Fig. 2 and 3,, magnetic clutch assembly 70 comprises columniform bell housing 72, it has continuous flange or a plurality of ear or lug 74, they have formed a plurality of for example through holes 76 of threaded fasteners 78 that hold, and fastener 78 can be convenient to shell filling to the shell of differential assembly shown in Figure 1 36 and therefrom remove.Cylinder blanket 72 holds and has supported antifriction assembly such as ball bearing assembly 80, and it supports bell input component 82 free to rotately.Input component 82 can comprise the minor axis 84 with male splines 86.Input minor axis 84 also can form other pressure transmission component, for example keyway, hexagonal tack etc.The second antifriction assembly such as ball bearing assembly 88 have supported cylindrical output hub 92 free to rotately.The inner cylindrical wall of input component 82 is formed with a plurality of female spliness or the gear teeth 94.

Cylindrical input component 82 and cylindrical output hub 92 radially between be provided with the power-transfer clutch ring or the collar 96, it has the outside thread 98 that is centered around on its periphery, the negative thread 102 on the inside face of outside thread 98 and input component 82 forms complementary and engagement.Therefore, as easy understanding, by suitably relatively rotating between them, the power-transfer clutch ring or the collar 96 just can be screwed on the input component 82 and therefrom screw down.Between power-transfer clutch ring or the collar 96 and output hub 92, be provided with roller bearing component 104.The power-transfer clutch ring or the collar 96 adjacent to the circumferential slot on the inside face of roller bearing component 104 108 in held leakage-free elastic sealing element 106, it provides the leakage-free sealing between output hub 92 and clutch collar 96.Also provide the leakage-free sealing by O-ring seals 112 between the outside face of the power-transfer clutch ring or the collar 96 and input component 82, sealing circle 112 is contained in the circumferential slot 114 of the power-transfer clutch ring or the collar 96.Output shaft 120 preferably includes male splines 122, and it matches and rotary the joint with female splines 124 on the cylindrical output hub 92.Be provided with suitable oil sealing 126 in output hub 92, it can roughly keep a leakage-free interior zone in cylindrical input component 82.Output shaft 120 comprises output bevel gear 128 integrally formed or that closely link to each other or be fixed together.

Refer now to friction clutch element self, the first magnetic clutch assembly 70 comprises elementary or guide's friction clutch assembly 130, it has first group of a plurality of larger-diameter clutch segment or clutch plate 132, and has the male splines that can engage with the female splines 94 in the input component 82.Therefore, larger-diameter fricting clutch plate or clutch plate 132 can be with input component 82 rotations.Second group of a plurality of clutch segment 134 than minor diameter is staggered in first group of a plurality of larger-diameter clutch segment or clutch plate 132, and have to be contained on the circular output hub 92 with female splines 136, the first circular pieces or the plate 140 that the male splines 138 of complementary structure on first circular piece or the plate 140 engages free to rotately.First and second groups of a plurality of clutch segments 132 and 134 comprise at least one the lip-deep suitable friction material that is arranged on each sheet.First circular slab 140 comprises a plurality of chute type cavitys 142, and its axis round output hub 92 is provided with conglobate pattern.Each cavity 142 has all formed a sloping portion of spiral anchor ring.

Be provided with load transfer ball 144 or similar load transfer part in each cavity 142, it can be along being rolled by the formed slideway in the inclined-plane of cavity 142.Larger-diameter second circular piece or plate 146 are arranged to form relative relation with first circular slab 140, and comprise the cavity 148 of similar a plurality of complementary sizes and setting.Therefore load transfer ball 144 just holds and is limited in double-type relative cavity 142 and 148, cavity 142 and 148 end are crooked, and the interior zone than cavity 142 and 148 on gradient is steeper, makes load transfer ball 144 to be limited in effectively in the formed zone.

Be appreciated that and adopt other similar mechanical component to replace cavity 142 and 148 and load transfer ball 144 that these mechanical components can cause

circular slab

140 and 146 to produce longitudinal travels in response to the relative rotation between them.For example, can adopt the interior wedge shape roller of conical pallidum that is arranged on complementary structure.

Cavity 142 and 148 and the important design of of load transfer ball 144 consider to be that the unit design of their geometric configuration and the first magnetic clutch assembly 70 and space have guaranteed that clutch pack 70 can be from engaging.The first magnetic clutch assembly 70 must not can from engaging, but must be directly, can clamp the friction clutch assembly in response to controller or incoming signal that microprocessor 50 provided pari passu with modulating.

Second circular slab 146 comprises a plurality of female spliness or the gear teeth 152, and they form complementary and engage with the male splines or the gear teeth 154 on the output hub 92.First or the guide's friction clutch assembly 130 and second circular slab 146 between be provided with circular slab 156, it has the spline 158 that can engage with the female splines 94 on the input component 82.

On the side opposite of first circular slab 140 or surface, be provided with annular flat packing ring 160 with second circular slab 146.Flat gasket 160 with first circular slab, 140 opposite surfaces on be provided with and support with annular element 162, it is placed in the circumferential V-slot 164 of clutch collar 96.

Flat gasket 160 is preferably made by plastics such as thermoplastic polyimide or materials similar.For example, the plastics Aurum JQC3025 that is produced by Mitsui Chemicals company is exactly suitable, also has Du Pont Vespel , and it is the polyimide plastic of a kind of engineering with low-friction coefficient.They all can provide good performance.This plastics should have sufficiently high PV value, so that can not consume certainly under load in application-specific and the velocity conditions.

Secondary or main friction clutch assembly 170 is on radially and between the surface of circumferentially extending of second circular piece 146 and input component 82.Main friction clutch assembly 170 comprises first group of a plurality of larger-diameter clutch segment or clutch plate 172, and it has the male splines 174 that can engage with spline 94 drive-types on the input component 82.Second group of a plurality of clutch segment or clutch plate 176 than minor diameter is staggered in first group of a plurality of larger-diameter clutch segment or clutch plate 172, and has the female splines 178 that can engage with the male splines 154 of complementary structure on the cylindrical output hub 92.Equally, first and second groups of a plurality of clutch segments 172 and 174 comprise at least one the lip-deep suitable friction material that is arranged on each sheet.

In the suitable cavity 182 of clutch collar 96, be provided with magnet coil 184.Magnet coil 184 links to each other with controller that electric energy can be provided or microprocessor 50 by one or more conductive cable 186.

In operation, for providing electric energy, magnet coil 184 plate 154 can be attracted and produced to drag towards clutch collar 96, this just trends towards making first circular slab or part 140 with respect to second circular slab or part 146 rotations, cause load transfer ball 144 in cavity 142 and 148 to arch, thereby order about plate or part 140 and opened in 146 minutes.Second plate 146 is as force application board, the compressible secondary or main friction clutch assembly 170 of this axial motion, and between input component 82 and output shaft 120 transfer torque.Flat gasket 160 amplifies or strengthens by moment of torsion elementary or that guide's friction clutch assembly 130 is produced.

Referring now to Fig. 2 and 4,, back axle assemble 36 also comprises the bevel gear diff and the second magnetic clutch assembly 190.The bevel gear diff and the second magnetic clutch assembly 190 are driven via side bevel gear 192 by output bevel gear 128, and output bevel gear 128 is as the output of the first magnetic clutch assembly 70.Side bevel gear 192 comprises bevel gear tooth 194.Side bevel gear 192 is fixed on the rotatable diff shell 196 by a plurality of threaded fastenerss 198, has shown one of them threaded fasteners 198 in Fig. 4.

In rotatable shell 196, be provided with bevel gear differential assembly 200.Bevel gear differential assembly 200 comprises minor axis 202, and its S. A. with respect to shell 196 is location radially, and is fixed on the S. A. by drive pin or other forward limiting mechanism (not shown).Rotatably be provided with a pair of unloaded bevel gear 204 round minor axis 202.Each unloaded bevel gear 204 includes bevel gear tooth 206, and preferably includes circular incision or recessed portion 208, and its other parts that can be differential assembly 200 provide the space.One offside bevel gear 210A and 210B and this mesh consistently to unloaded bevel gear 204.These two side bevel gear 210A and 210B comprise female splines or gear teeth 212A and 212B respectively, they can be respectively engage with the spline 214A and the 214B of complementary structure on a pair of symmetrically arranged output shaft 216A and the 216B, and

output shaft

216A and 216B can drive Y-axis 38 respectively.A pair of oil sealing 218A and 218B provide the leakage-free sealing between

axle

216A and 216B and outer hull 220 separately.Rotatable shell 196 is supported in the outer hull 220 by a pair of antifriction bearings such as tapered roller bearing assembly 222A and 222B.Between left side bevel gear 210A and rotatable shell 196, operationally be provided with the secondary or main friction clutch assembly 226A in left side, it has first group of a plurality of bigger clutch segment or clutch plate 228A, and they are connected on the rotatable shell 196 by the spline that is bonded with each other.

Second group of a plurality of less clutch segment or clutch plate 232A are staggered in first group of a plurality of bigger clutch segment or clutch plate 228A, and are connected on the bevel gear 210A of left side by the spline that is bonded with each other.Substantially symmetrically be provided with the secondary of right side or main friction clutch assembly 226B with the secondary of left side or main friction clutch assembly 226A, it has first group of a plurality of bigger clutch segment or clutch plate 228B, and they are connected on the rotatable shell 196 by the spline that is bonded with each other.Second group of a plurality of less clutch segment or clutch plate 232B are staggered in first group of a plurality of bigger clutch segment or clutch plate 228B, and are connected on the bevel gear 210B of right side by the spline that is bonded with each other.Should be appreciated that the gradual compression of being located at respectively between side bevel gear 210A and 210B and the rotatable shell 196 secondary or main

friction clutch assembly

226A and 226B has suppressed the differential of diff and second clutch assembly 190 step by step.

Referring now to Fig. 4,, 5 and 6, the compression of main

friction clutch assembly

226A and 226B is realized by Electromagnetically-operating device assembly 240.Electromagnetically-operating device assembly 240 comprises fixing magnet coil 242, comes to provide electric energy for it by one or more conductive cable 244.Electromagnetically-operating device assembly 240 comprises elementary or guide's friction clutch 246, and it has first group of a plurality of bigger clutch segment or the clutch plate 248 that engages with circumferential collar free to rotate 252 splines.Interleaved second group of less clutch segment or clutch plate 254 engage with the first stressed collar 256 splines.The stressed collar 256 also links to each other with right side bevel gear 210B by the spline that is bonded with each other and can rotate thereupon.Be provided with flat circular magnetic packing ring 258 on a side opposite with magnet coil 242 of elementary or guide's friction clutch 246, it engages with the application of force collar 256 splines.

Electromagnetically-operating device assembly 240 also comprises ball slideway operator assembly 260, and it has the first circular actuator 262 that engages and can rotate thereupon with circumferential collar 252 splines.The first circular actuator 262 can engage and exert pressure, so that the stressed collar 256 is towards the secondary of right side or main friction clutch assembly 226B motion.First circular piece 262 comprises a plurality of cavitys 264, and each cavity has formed a sloping portion of spiral anchor ring.First circular piece 262 has been preferably formed as three this cavitys 264.Each cavity 264 has held a load transfer ball 266.The second circular actuator 268 is formed with similar a plurality of symmetrical cavity 272.The second circular actuator 268 is radially enlarged parts on the ring 274, and ring 274 extends beyond axle 202 left, and engages with L shaped round force application board 276.Rotation between ring 274 and the circle force application board 276 is prevented that by one group of surface spline 278 or being bonded with each other of similar structures these similar structures from for example being lug and cavity on the adjacently situated surfaces that is arranged on ring 274 and force application board 276 with complimentary fashion.Force application board 276 engages with shell 196 splines and can rotate thereupon.

Cavity 264 and 272 and the important design of of load transfer ball 266 consider to be that the unit design of their geometric configuration and the second magnetic clutch assembly 190 and space have guaranteed that clutch pack 190 can be from engaging.The second magnetic clutch assembly 190 must not can from engaging, but must be directly, can clamp the friction clutch assembly in response to controller or incoming signal that microprocessor 50 provided pari passu with modulating.

At last, Electromagnetically-operating device assembly 240 comprises the flat gasket 282 that is arranged between the first circular actuator 262 and the stressed member 256.Flat gasket 282 is preferably made by plastics such as thermoplastic polyimide or materials similar.For example, the plastics Aurum JQC3025 that is produced by Mitsui Chemicals company is exactly suitable, also has Du Pont Vespel , and it is the polyimide plastic of a kind of engineering with low-friction coefficient.They all can provide good performance.This plastics should have sufficiently high PV value, so that can not consume certainly under load in application-specific and the velocity conditions.

In operation, the bevel gear diff and the second magnetic clutch assembly 190 provide modulation or the proportional control between first operation mode or state and second operation mode or state, in first operation mode, the diff connected provide between two output shaft 216A and the 216B differential (and if on bevel gear 192, apply moment of torsion, then also can transfer torque), in second operation mode, differential being suppressed, the

axle

216A and 216B is locked effectively and together the rotation.The electric energy that offers magnet coil 242 by adjusting come pro rata or modulation system actuate second magnetic clutch, thereby realize these two limiting conditions and the differential level of selecting arbitrarily of part.When the electric energy that offers magnet coil 242 increases, produced the electromagnetic flux that increases, on elementary or guide's friction clutch 246, produced and dragged.Formedly drag that making wins between the circular actuator 262 and the second circular actuator 268 forms rotation relatively, cause load transfer ball 266 that circular actuator 262 and 268 points are opened, thereby compress secondary or main friction clutch assembly 226A and 226B.The compressor mechanical formula of

friction clutch assembly

226A and 226B ground and operationally resulting between side bevel gear 210A and 210B and the rotatable shell 196, thus can be little by little and controllably suppress the differential of bevel gear differential assembly 200.The excitation fully of magnet coil 242 can suppress the differential of differential assembly 200.

According to the present invention, back axle or secondary bridges assembly 36 have three kinds of different operation modes or state.For simplicity's sake, these three kinds of operation modes are described to different make-break operation modes, be appreciated that to the modulation of above-mentioned these patterns or proportional control always can be implemented in disconnect fully and connect fully between the joint of selected degree.First operation mode relates to be had only the first magnetic clutch assembly 70 to be excited or actuates.In this operation mode, moment of torsion is delivered in the bevel gear differential assembly device 200 and the second magnetic clutch assembly 190.Because the second magnetic clutch assembly is not excited, so the diff of bevel gear differential assembly device 200 for connecting, there is velocity contrast in its permission between two

axle

216A and 216B, and traditional differential operation is provided.

Second operation mode or state comprise having only the second magnetic clutch assembly 190 to actuate and engage, and it can suppress the differential of bevel gear differential assembly device 200.Under this pattern, do not have moment of torsion can be delivered among rear axle 216A and the 216B, but they link together by secondary or main

friction clutch assembly

226A and 226B, thereby can operate as vehicle with a whole back axle.

In the 3rd operation mode or state, the second magnetic clutch assembly 190 of the first magnetic clutch assembly 70 and bevel gear differential assembly device all engages.In this case, moment of torsion is provided among rear axle 216A and the 216B, but differential being suppressed of gear differential assembly device 200.In this case, moment of torsion is delivered among the

rear axle

216A and 216B that rotates with identical speed.As mentioned above, the magnetic clutch assembly as modulating clutch can carry out the operation of local engagement in all mentioned operations pattern or state.

Above-mentioned openly is the designed optimal mode that goes out of the artificial the present invention of enforcement of invention.Yet clearly, it is conspicuous having comprised the device that improves and change for the back axle assemble those of skill in the art with magnetic clutch and gear differential mechanism.Owing to above-mentionedly open just enable those skilled in the art to implement the present invention, so the present invention is not limited to above-mentioned openly, and it should be interpreted as having comprised the conspicuous change of above-mentioned this class, and only limited by the scope and spirit of claims.

Claims

1. back axle (36) that is used for automobile power-transmission system, it includes with combined form:

First magnetic clutch (70), it has input component (82), output (120), operationally is arranged on the first friction clutch assembly (170) between described input component and the output, and the first Electromagnetically-operating device (130) relevant with the described first friction clutch assembly

Bevel gear differential assembly (200), it has by the rotatable shell (196) of the described output driving of described first friction clutch, a pair of side bevel gear (210A that is arranged in the described shell and can drives corresponding a pair of output shaft, 210B), and a pair of unloaded bevel gear (204) that is arranged in the described shell and can engages with described side bevel gear

Second magnetic clutch, it has at least one and operationally is arranged on the second friction clutch assembly (226A between in a described rotatable shell and the described offside bevel gear one, 226B), and the second Electromagnetically-operating device (240) relevant with the described second friction clutch assembly.

2. back axle according to claim 1 is characterized in that, described second friction clutch comprises two described second friction clutch assemblies.

3. back axle according to claim 1 is characterized in that, the described second friction clutch assembly operationally is arranged between each gear and described rotatable shell in the described offside bevel gear.

4. back axle according to claim 1 is characterized in that, described Electromagnetically-operating device comprises ball slideway actuator, it has the relative part that can rotate each other (140,146,262 that has formed cavity, 268) and be located at load transfer part (144,266) in the described cavity.

5. back axle according to claim 1 is characterized in that described power-transfer clutch can be actuated independently.

6. back axle according to claim 1 is characterized in that, described back axle also comprise by the corresponding a pair of output shaft that operationally drives in the described offside bevel gear (216A, 216B).

7. back axle according to claim 1 is characterized in that, each described magnetic clutch includes primary clutch assembly (132,134) and secondary clutch assembly (170).

8. back axle (36) that is used for automobile power-transmission system, it includes with combined form:

First magnetic clutch (70), it has input component (82), output (120), operationally is arranged on first clutch assembly (170) between described input component and the output, and relevant with described first clutch assembly first mechanical arm (130) that can produce power

Bevel gear differential assembly (200), it has rotatable shell (196), a pair of side bevel gear (210A that is arranged in the described shell by the described output driving of described first friction clutch, 210B), and a pair of unloaded bevel gear (204) that is arranged in the described shell and can engages with described side bevel gear

Second friction clutch, it has at least one and operationally is arranged on second clutch assembly (226A between in a described rotatable shell and the described offside bevel gear at least one, 226B), and relevant with described second friction clutch second mechanical arm (240) that can produce power.

9. back axle according to claim 8 is characterized in that, the mechanical arm of the described power of generation comprises magnet coil (184,242).

10. back axle according to claim 8 is characterized in that, the mechanical arm of the described power of generation comprises ball slideway actuator, it has the relative part that can rotate each other (140,146,262 that has formed cavity, 268) and be located at load transfer part (144,266) in the described cavity.

11. back axle according to claim 8 is characterized in that, described side bevel gear can drive a pair of output shaft (216A, 216B) the corresponding output shaft in.

12. back axle according to claim 8 is characterized in that, described friction clutch comprises the pilot clutch assembly of being actuated by magnet coil (184,242).

13. back axle according to claim 8 is characterized in that, described friction clutch comprise the master clutch assembly of actuating by ball slideway mechanical arm (170,226A, 226B).

14. back axle according to claim 8 is characterized in that, described back axle also comprises the described output that operationally is arranged on described first friction clutch and the bevel gear group (128,192) between the described rotatable shell.