Abstract: This application describes examples of a differential device, a powertrain, and a vehicle. In one example, the differential device includes a housing, three planetary gears, two side gears, and at least one window. Each of the three planetary gears is mounted on an inner wall of the housing through a pin shaft, the three planetary gears are disposed spaced from each other along a circumferential direction of the housing. The two side gears are disposed on two sides of the three planetary gears along the axial direction of the housing and meshed with the three planetary gears. The main reduction gear drives the housing to rotate around the axial direction of the housing, so that the three planetary gears drive the two side gears to drive two drive shafts respectively.

Abstract: A gearwheel (20) for a gear step in an electric vehicle transmission (18) includes a gearwheel carrier and a toothed ring (30) having an external toothing (42). The toothed ring is rotationally fixable to the gearwheel carrier. The gearwheel carrier is formed by a first partial carrier (38) and a second partial carrier (40) that are at least partially axially spaced apart and extend from the toothed ring radially inward. An axial spacing of the two partial carriers is greater, at least partially, than an axial length of the toothed ring.

Abstract: A differential includes two magnetic gears each having an internal rotor, an external rotor, and a rotor of the ferromagnetic poles interposed between the internal and the external rotors. The internal rotor, the external rotor and the rotor of the ferromagnetic pole are coaxial and rotate about a gear axis. The internal rotors are connected to a drive, to be placed in rotation about a respective gear axis by the drive. With external rotors suitable for being connected to respective output semi-axes for placing them in rotation, the rotors of the ferromagnetic poles are connected to adjustment means suitable for adjusting the rotation speed of the rotors of the ferromagnetic poles. With external rotors connected to adjustment means suitable for adjusting their rotation speed, the rotors of the ferromagnetic poles are connected to respective output semi-axes for placing them in rotation.

Abstract: A differential gear assembly for a vehicle includes: an annular ring gear having internal and external surfaces, and rotates around a rotational axis extending in an axial direction; first and second side gears respectively distribute a first and second output torque to first and second drive shafts; first and second differential pinion gears respectively engage the first and second side gears; a pinion pin extends diametrically across the ring gear, where the first and second differential pinion gears are rotatably arranged on the pinion pin. The ring gear comprises first and second slots for receiving the pinion pin, where the slots are arranged in connection to the internal surface and extend partly through the ring gear in the axial direction.

Abstract: A differential gear includes a holder which is provided between first and second pinion gears in a differential case and through which a differential pinion shaft is inserted. An insertion hole is radially formed in the differential pinion shaft. The holder is formed with a fixing hole facing the insertion hole when the differential pinion shaft is inserted through the holder. Due to insertion of a fixing pin through the fixing hole and the insertion hole, the differential pinion shaft and the holder are relatively non-rotatable. Due to the holder being held between first and second side gears, relative rotation of the holder with respect to the differential case is restricted, and the differential pinion shaft is non-rotatable relative to the differential case.

Abstract: An axle assembly and a method of manufacture. The axle assembly may include a differential carrier and a bearing support wall. The differential carrier may be made of a first material. The bearing support wall may be mounted to the differential carrier and may be made of a second material. The second material may have a greater stiffness than the first material.

Abstract: A line of vehicle transmissions is provided. The vehicle line includes a first multi-stage gear train assembly with at least two stages, a second multi-stage gear train assembly with at least three stages, and a housing including a first section removably attached to a second section. The second housing section is configured to receive the first and second multi-stage gear train assemblies in different product arrangements.

Abstract: A rotation converter configured to convert an alternative clockwise-counterclockwise rotation to a single rotation direction, including: a hex shaft including an input hex, an output hex, and a gear contact, wherein the input hex and output hex are separated by the gear contact; a hex mover coupled to the input hex, wherein the hex mover includes following teeth and driving teeth; a following ring gear in contact with the following teeth; a driving ring gear in contact with the driving teeth; one or more gear pinions in contact with the following ring gear and the driving ring gear; one or more gear rods configured to support the one or more gear pinions; and a gear holder coupled to the one or more gear rods.

Abstract: The invention relates to a differential or transfer gearbox (10) in a motor vehicle, a method of production and the use of the differential or transfer gearbox (10). The differential or transfer gearbox (10) comprises a differential case (12) in which differential side gears (18, 20) and differential gears (22, 24) are accommodated. Each differential side gear (18) drives a first axle shaft (14) or a second axle shaft (16). A ring gear (32, 60) is driven by an input shaft (34) and mounted for conjoint rotation with the differential case (12). The ring gear (32, 60) is interlockingly connected to the differential case (12) of the differential or transfer gearbox (10).

Abstract: Each of a differential carrier and a differential retainer of a differential housing includes a bearing attachment portion, a flange portion, and a mount portion. The flange portion of the differential carrier and the flange portion of the differential retainer are fastened to each other via a plurality of through-holes provided in at least either one of the flange portion of the differential carrier and the flange portion of the differential retainer. At least either one of the differential carrier and the differential retainer includes a plurality of reinforcement rib portions provided on an outer wall side of the at least either one of the differential carrier and the differential retainer, the reinforcement rib portions extending from the position of the bearing attachment portion toward the positions of some of or all of the through-holes and the mount portion.

Abstract: A system is provided for shielding a tone ring assembly in automotive vehicles. The system comprises a ring cap with a central aperture, a plurality of molding slides circularly arranged on a first side of the ring cap, a plurality of snap-fit arms and a plurality of pilot tabs positioned on a second side of the ring cap, where the plurality of pilot tabs and the plurality of snap-fit arms are arranged in concentric circles with the snap-fit arms forming an outer circle and the pilot tabs forming an inner circle, and where each pilot tab of the plurality of pilot tabs is positioned directly behind a corresponding snap-fit arm of the plurality of snap-fit arms. In one example, the system prevents metal to metal contact between a tone ring and a shaft during axle shaft installation.

Abstract: A tone wheel assembly includes a tone wheel. A first member is attached to the tone wheel. A second member is at least partially disposed around a portion of the first member. The second member includes a collar portion, one or more first leg portions extending axially from the collar portion, and one or more second leg portions extending axially from the collar portion. The one or more first leg portions include a first leg portion protuberance that extends radially from an outer surface of the one or more first leg portions. The one or more second leg portions include a second leg portion protuberance that extends radially from an outer surface of the one or more second leg portions.

Abstract: An axle assembly with a housing, an annular gear, a bearing, a differential, and a pair of output shafts. The housing has an annular hub. The annular gear is received in the housing. The bearing, which is a four-point angular contact bearing, supports the gear for rotation about an axis relative to the housing and has an inner bearing race, which is mounted on the annular hub, and an outer bearing race that is fixedly coupled to the annular gear. The differential is received in the housing and includes an input member, which is coupled to the annular gear for rotation therewith, and a pair of output members that are rotatable relative to the input member about the output axis. Each of the output shafts is coupled to an associated one of the output members for rotation therewith. One of the output shafts extends through the annular hub.

Abstract: A disconnect apparatus including a first clutch member and a second clutch member in selective engagement with the first clutch member. The disconnect apparatus also includes a cam mechanism and a sensor assembly. The cam mechanism includes an axially movable first cam member and an axially fixed second cam member, wherein the sensor assembly generates a pulse pattern which is utilized to determine a position of the first cam member, and thereby a state of the disconnect apparatus.

Abstract: An axle assembly that includes an axle housing, a differential carrier, and an electric motor module. The differential carrier that is mounted to the axle housing and rotatably supports a differential. The electric motor module is received inside the differential carrier and is operatively connected to and provides torque to the differential.

Abstract: A differential assembly includes a first case rotatable about an axis and defining a first mounting flange having a through hole and a second case abutting the first case to define a gear nest cavity therebetween. The second case further defines a second mounting flange having a through hole and formed to mate to the first mounting flange. The differential assembly also includes a ring gear mounted to the first mounting flange and fastener extending through the through hole of both the first mounting flange and second mounting flange into a fastener hole of the ring gear. Additionally, the first mounting flange is sandwiched between the second mounting flange and the ring gear.

Abstract: A differential hypoid gear, a pinion gear, and paired hypoid gears formed by a combination thereof are provided. The differential hypoid gear includes a ring-shaped main body and a tooth-forming surface, and has a chemical component composition including C: 0.15-0.30 mass %, Si: 0.55-1.00 mass %, Mn: 0.50-1.20 mass %, Cr: 0.50-1.50 mass %, Al: 0.020-0.080 mass %, B: 0.0005-0.0050 mass %, Ti: 0.01-0.08 mass %, N: 0.0020-0.0100 mass %, Mo: 0.25 mass % or less, and Nb: less than 0.10 mass %, the remainder being Fe and unavoidable impurities. The chemical component composition satisfies Formulae 1 and 2. The differential hypoid gear has a metallographic structure including mainly tempered martensite. A martensite ratio at an inside of a dedendum differs between an end portion of a tooth and a central portion of the tooth within a range of 15% or less. A core hardness of the dedendum at the central portion falls within 350-500 HV.

Abstract: Disclosed herein is an axle assembly and a heavy load vehicle comprising the axel assembly. The axle assembly comprises an interaxle differential configured to distribute torque to first and second axles. The interaxle differential comprises an input shaft and an output shaft. A first gear wheel is journaled in a first bearing about the input shaft. The input shaft is journaled in relation to the output shaft via a tapered roller bearing having a small end and a large end. A lubricant receiving space is fluidly connected to the small end of the tapered roller bearing, and the large end of tapered roller bearing is fluidly connected to the first bearing. Thus, the first bearing is lubricated when there exists a difference in rotational speed between the input and output shafts.

Abstract: A vehicle driveline component with a differential case, a cross-pin, a differential gearset, and a retaining member. The differential case is rotatable about a first axis and has an annular wall member that defines a differential cavity. The cross-pin is received in a cross-pin aperture formed through a first side of the annular wall member. The cross-pin extends through the differential cavity along a second axis that is perpendicular to the first axis. The differential gearset is received in the differential cavity and includes a pair of side gears, which are rotatable about the first axis, and a pair of pinion gears that are journally supported by the cross-pin and meshingly engaged with the side gears. The retaining member is welded to the annular wall member and limits movement of the cross-pin relative to the differential case along the second axis in a direction toward the retaining member.

Abstract: A gear shroud arrangement includes a plate defining an aperture therethrough. A riser tube has a first end and an opposed second end. The first end of the riser tube is connected to the plate and is aligned with the aperture. A mounting flange extends from the second end of the riser tube. A shroud member extends from the plate in a direction opposite the riser tube.

Abstract: A vehicle drive device that includes a rotating electrical machine that serves as a drive power source for a first wheel and a second wheel; a differential gear device that distributes drive power from the rotating electrical machine to the first wheel and the second wheel; a reduction device that includes a planetary gear mechanism with a sun gear, a carrier, and a ring gear; and a case that accommodates the rotating electrical machine, the differential gear device, and the reduction device.

Abstract: A gear assembly is provided that simplifies the integration of a differential assembly into the hollow rotor of an electric motor. The gear assembly utilizes a hollow cross member that includes a central portion and a plurality of hollow extension members onto which the gears are mounted. Within each of the hollow extension members is a pin. When the pins are withdrawn, the assembly fits unimpeded within the hollow rotor. When the pins are partially extended out of the corresponding extension members, the ends of the pins fit within apertures in the rotor. A plug fits within a centrally located thru-hole in the central portion of the hollow cross member, thereby locking the pins in the extended position and locking the gear assembly in place.

Abstract: A vehicular differential device includes a differential case, a ring gear, and a welded portion positioned on an abutting surface where the differential case and the ring gear are in contact with each other. The welded portion is configured to join the differential case and the ring gear for integral rotation of the differential case and the ring gear around a rotation axis of the vehicular differential device. The welded portion includes a plurality of welding surfaces positioned at predetermined intervals along a circumferential direction around the rotation axis.

Abstract: A differential device includes a plurality of differential gears, a plurality of differential gear support members respectively supporting the plurality of differential gears, a pair of output gears meshing with each of the plurality of differential gears, a support member having a plurality of opposite ends-supporting parts supporting opposite end parts of the respective differential gear support member, and a space being formed in a middle part of the support member, a recess part being formed between two of the opposite ends-supporting parts of the support member that are adjacent to each other, the recess part extending from an outside in a radial direction of the support member toward an inside in the radial direction, each of the plurality of opposite ends-supporting parts having one support portion supporting at least one end part of the differential gear support member, and a through hole being formed in the one support portion.

Abstract: A vehicle driveline component that employs a latching actuator to toggle between a first operation mode and a second operational mode. The latching actuator includes first and second actuator structures, a biasing spring, which biases the second actuator structure away from the first actuator structure, a linear motor, which can be operated to drive the second actuator structure toward the first actuator structure, and a plurality of linkages that cooperate with the biasing spring to releasably lock the second actuator structure relative to the first actuator structure in each of an extended position and a retracted position.

Abstract: A differential assembly is provided to include a two-piece differential carrier, a differential gearset installed within a gearset chamber formed in the differential carrier, and a ring gear. An interlocking feature mechanically interconnects the ring gear to the first and second case members of the two-piece differential carrier and defines first and second weldment junctions. A first weld seam is located in the first weldment junction and connects the ring gear to the first case member while a second weld seam is located in the second weldment junction and connects the ring gear to the second case member.

Abstract: A drive torque received from a power source is split and output to first and second output shafts through a torque vectoring apparatus including a torque vectoring device that controls a torque ratio of split torques, where the torque vectoring device includes a control motor, a first compound planetary gear set including first and second planetary gear sets having a first rotation element fixed to a housing, a shared second rotation element connected to the first output shaft, and a third rotation element, and a second compound planetary gear set including third and fourth planetary gear sets having a shared fourth rotation element connected to the second output shaft, a fifth rotation element connected to a third rotation element, and a sixth rotation element connected to the control motor.

Abstract: A differential apparatus includes a differential gear mechanism in which side gears mesh with pinion gears, a pinion shaft that rotatably supports the pinion gear, a slide member that supports the ends of the pinion shaft, and pinion gear washers each disposed between the slide member and a corresponding one of the pinion gears. Movement of each pinion gear washer toward the slide member in the axial direction of the pinion shaft is restricted. When a force of the pinion gear pressing the pinion gear washer toward the slide member is less than a predetermined value, a clearance is formed between the slide member and the pinion gear washer. When the force of the pinion gear pressing the pinion gear washer toward the slide member is greater than the predetermined value, the outer surface of the pinion gear washer abuts the inner surface of the slide member.

Abstract: A differential gear mechanism constructed in accordance to one example of the present disclosure can include a differential case, a clutch pack and a plurality of lock pins. The differential case can include a first differential case portion that defines a first output shaft opening and includes a plurality of clutch ear guides and a plurality of lock pin engaging surfaces. The clutch pack can include a plurality of annular plates that are interleaved between a plurality of annular friction disks. At least one of the annular plates and annular friction disks can include a plurality of radially extending plate ears that are received by the corresponding plurality of clutch ear guides. The plurality of lock pins can be received by the plurality of first lock pin engaging surfaces of the first differential case at locations in-line with the clutch ear guides.

Abstract: A bearing arrangement for rotatably supporting a pinion shaft in a housing is described. A pinion of the pinion shaft interacting with a ring gear, the pinion shaft being mounted in the housing by way of two axial bearings and a radial bearing which is arranged between the axial bearings.

Abstract: A case for a differential gear set includes: a rotatable carrier having a cylindrical fitting face and a radially projecting flange having an axially directed butting face; a cover having a brim section so projecting axially as to fit on an outer periphery of the flange and so dimensioned as to align an end face of the brim section with the butting face; a ring gear fitting on the fitting face and having a back face in contact with the butting face; and a weld metal uniting the carrier, the cover and the ring gear together, wherein the butting face of the carrier, the end face of the cover and the back face of the ring gear are so dimensioned as to keep a circular groove exposed outward and reaching an interface between the back face and the butting face and the weld metal fills the groove.

Abstract: An axle carrier includes a housing having an outer surface, an inner surface defining an interior portion, a first axle support member, and a second axle support member. The body is formed from a first material. A gear carrier is arranged within the interior portion. The gear carrier is formed from a second material. The first material comprises a metal matrix composite having a coefficient of thermal expansion (CTE) that substantially matches a CTE of the second material.

Abstract: A vehicle drivetrain assembly having a clutch collar actuator mechanism. The clutch collar actuator mechanism may include an air bellow and a fork that may operatively connect an actuator rod to a clutch collar. The clutch collar actuator mechanism may actuate the clutch collar from a first position to a second position when the air bellow is inflated.

Abstract: A differential unit includes: a differential case; a differential mechanism; a connecting-disconnecting member that connects the differential case to the differential mechanism; an actuator that generates a moving force for moving the connecting-disconnecting member; a moving-force transmitting member that transmits the moving force generated by the actuator to the connecting-disconnecting member; and a wave washer that urges the connecting-disconnecting member in a direction opposite to a direction in which the connecting-disconnecting member is moved by the actuator. The actuator includes a plunger that moves while compressing the wave washer in the axial direction from a first prescribed length using a magnetic force of an electromagnet. A movement of the plunger in a direction away from the connecting-disconnecting member is restricted by a contacting portion of a restricting member.

Abstract: An axle assembly having a first clutch collar and a second clutch collar. The first clutch collar may be selectively engageable with a drive gear that may be rotatably disposed on an input shaft. The second clutch collar may be selectively engageable with a side gear of an interaxle differential unit.

Abstract: A drive switching apparatus includes an output member connected to a drive switching member and displacing the drive switching member to three shift positions by being rotated, a deceleration mechanism decelerating rotation of an input portion connected to an electric motor and outputting the rotation to an output portion, a rotation absorption mechanism including an elastic member interposed between an input element connected to the output portion and an output element connected to the output member, the rotation absorption mechanism absorbing rotation of the input element in a case where rotation of the output element is restricted during the rotation of the input element, and a switch operation portion provided at the output element, the switch operation portion turning a switch on and off according to a rotational position of the output member in order to detect the shift positions of the drive switching member.

Abstract: In a transmission device, a flange portion includes: first outer peripheral portion fitted and welded to inner peripheral portion of ring gear; second outer peripheral portion small in diameter and adjacent to the first outer peripheral portion via first connecting surface; and third outer peripheral portion smaller in diameter and adjacent to the second outer peripheral portion on the opposite side from the first outer peripheral portion via second connecting surface. The ring gear includes space forming portion defining, between it and the flange portion, space faced by inner end of welded portion and extending radially inward and outward of the welded portion. Side surface of the stopper portion abuts against the second connecting surface, the stopper portion being formed in the ring gear and having inner peripheral surface press-fitted to the third outer peripheral portion.

Abstract: A differential is disclosed for use with a drivetrain of a mobile machine. The differential may have an input gear, a first side gear, a second side gear, and a side pinion disposed axially between and intermeshed with the first and second side gears. The differential may also have a carrier nested inside of the input gear and connected to the input gear and the side pinion. The carrier may at least partially surround the first side gear and the second side gear.

Abstract: A vehicle differential includes a pair of side gears, a pinion gear, a differential case, and an annular ring gear. The differential case includes an opening penetrating a peripheral wall of the differential case. The annular ring gear is attached to an outer side of the peripheral wall of the differential case such that a central axis of the annular ring gear and a rotational axis of the differential case coincide with each other. The annular ring gear includes a protrusion on an inner peripheral edge of the annular ring gear. The protrusion covers a part of the opening when viewed in a penetration direction of the opening. The protrusion protrudes toward the inner side of the opening in the radial direction of the rotational axis as compared with an other part of the inner peripheral edge of the annular ring gear that has no protrusion.

Abstract: A weld structure includes a fitting portion at which a first member and a second member are engaged, a weld portion at which the first member and the second member are welded together, and a space between the fitting portion and the weld portion. One of the first member and the second member has a communication passage whose one end is open to the space and whose other end is open to an outside at a position other than the space. The communication passage is blocked by an insertion member that has a predetermined function in addition to blocking the communication passage.

Abstract: A powertrain includes a front differential configured to distribute torque to two front half-shafts. The differential includes a carrier body and a drive gear formed into an exterior surface of the carrier body. The powertrain further includes a power take-off unit configured to transfer torque from the carrier body to a rear axle. The unit has a PTU gear meshed with the drive gear.

Abstract: A differential gear for a motor vehicle includes a housing with a first housing part and a second housing part, and at least one bolt on which two differential gear wheels are arranged. The first housing part is configured integrally with an input element and the second housing part has at least two mutually opposing receiver openings. Bolt ends of the bolt are received in the receiver openings so that end faces of the bolt in the region of the two bolt ends, together with the outside of the second housing part, form a housing outer face. The first housing part, the second housing part, and the bolt are connected together by a peripheral radial weld seam.

Abstract: A differential apparatus includes a differential mechanism, a differential case that accommodates the differential mechanism, and a clutch mechanism that transmits a driving force between the differential case and the differential mechanism. The clutch mechanism includes a slide member movable inside the differential case in an axial direction and an actuator. The slide member has a first meshable portion at one end in the axial direction, is allowed move relative to the differential mechanism in the axial direction, and is prevented from rotating relative to the differential mechanism. The differential case includes a first case member and a second case member that are united to form the differential case. The first case member integrally includes a second meshable portion and a flange portion that the ring gear is fastened to.

Abstract: An integrated pinion, bearing and coupling (PBC) assembly for use with a hypoid gearset in power transfer assemblies of motor vehicles. The PBC assembly includes a pinion unit having a pinion gear segment and a pinion stub shaft segment, and a coupler unit having a coupling flange segment and a coupler shaft segment. The pinion stub shaft segment surrounds and is in press fit engagement with the coupler shaft segment. A portion of the coupler shaft segment is deformed to be retained within one of a receiver groove and raised projections formed in the pinion stub shaft segment so as to fixedly secure the coupler unit to the pinion unit.

Abstract: A powered axle gear (I) for a motor vehicle. The axle gear can cope with large driving torques and at the same time be accommodated in an axle beam between the vehicle's tractive wheels. The axle gear has a gear housing (10) which accommodates a pinion (40) and a crownwheel (50) for transmission of rotary motion to the vehicle's powered axles (Y1, Y2). To this end, there are two bearings (62, 64), one on each side of the crownwheel (50) and the pinion's centerline (X), with a differential situated between the bearings (62, 64). The bearing (64) situated beyond both the crownwheel (50) and the pinion's centerline (X) has running round it an undivided bearing seat (30) provided with a portion running in the circumferential direction which protrudes over the pinion (40) towards the latter's centerline (X) in a configuration which at least partly overlaps the pinion (40). The invention relates also to a motor vehicle with this axle gear.

Abstract: A differential for use in a vehicle drive train having a pair of rotary members including a gear case that is operatively supported in driven relationship with respect to the drive train and a pair of side gears mounted for rotation with a respective one of the rotary members in the gear case. The differential also includes a spider mounted for rotation with the gear case and at least one pair of pinion gears mounted for rotation with the spider and in meshing relationship with the side gears. The side gears have concave teeth flanks and the pinion gears have convex teeth flanks to increase power density through the differential.

Abstract: A selectively lockable differential, comprising a plurality of torque sensitive pins, an outer housing, a first side gear comprising first gear teeth, a second side gear comprising second gear teeth, a pinion shaft, two pinion gears rotationally coupled to the pinion shaft, each pinion gear comprising pinion gear teeth coupled to the first gear teeth and the second gear teeth, and a collar comprising collar teeth for selectively engaging the gear lugs of the first side gear, the torque sensitive pins operatively coupling the collar to the outer housing.

Abstract: A cast aluminum differential housing for a motor vehicle powertrain having cast iron inserts. The housing is cast of light weight aluminum which weighs approximately one-third that of iron which has formerly been used to fabricate such housings. At locations of significant loads and wear, such as the mountings for the stub shaft associated with the two idler bevel gears, iron inserts are cast into the housing. The housing thus weighs significantly less than a comparable iron differential housing but since the two significant wear and load bearing regions include cast iron inserts, the aluminum differential housing of the present invention has the ruggedness, durability and service life of the much heavier iron housing.

Abstract: A differential device includes: a differential gear mechanism; and an integrated differential case housing the mechanism, the differential case including bearing bosses formed integrally on one and other side portions thereof and aligned on a same axis to be rotatably supported by a transmission case; a work window being provided in the differential case; sleeves rotatably supported by the bosses and connected to side gears of the mechanism liquid-tightly. The sleeves can be passed through an inside of the differential case from the window and fitted and inserted to inner peripheries of the bosses, sleeve retainers are provided between the sleeves and the bosses, and seal devices for preventing lubricating oil in the differential case from flowing out are provided between the side gears and the sleeves. Accordingly, when drive shafts are removed from the differential device, the oil in the transmission and differential cases does not flow out.

Abstract: A motor vehicle differential gear has at least one housing part as a first gear part, and a crown wheel as a second gear part. The first and second gear parts are connected via respective first connection surfaces running in the axial direction by a press fit, and via respective second connection surfaces running at an angle to the axial direction, forming a welding seam. One of the gear parts is formed from a steel and the other gear part from a cast iron material, as well as such a differential gear in which the second connection surfaces connect directly to the first connection surfaces.