SE538167C2 - Locking device for locking a gear on an axle in a gearbox - Google Patents

Abstract

Summary The present invention relates to a loading device (21) for loading a gear (15) on a rotatable shaft (11) in a gearbox. The welding device (21) comprises a carrier unit (25), a coupling sleeve (26) and a gear unit (27). Each of the coupling sleeve teeth (31) comprises a welding part (31a) which is adapted to be flared into a space (34) between adjacent teeth (33) of the gear unit (27) in a load bearing. The welding part (31a) has a line between a front end (31d) which in the welding layer is adapted to be arranged in connection with an inner spirit (34b) of the space (34) and a rear end (31e) which in the welding layer is adapted to be arranged in connection to an opening (34a) of space (34). The welding part (31a) has a width which runs continuously from the front spirit (31d) to the rear spirit (31e) and that space (34) has a corresponding width as the welding part (31a) both in size and shape so that the welding part (31a) substantially fills the entire width of the space (34) in the welding layer.

Description

BACKGROUND OF THE INVENTION AND PRIOR ART The invention relates to a loading device for loading a gear on a shaft in a gearbox according to the preamble of claim 1.

Conventional gearboxes comprise a side shaft, a main shaft, a plurality of gear pairs each comprising a gear which is rotatably mounted on the side shaft and gears which are rotatably mounted on the main shaft. A locking device for loading a gear on the main shaft generally comprises an axially displaceable coupling sleeve which is in constant engagement with a carrier on the main shaft via a toothed portion comprising teeth and intermediate spaces with an axial tension. The coupling sleeve thus rotates at the same speed as the carrier and the main shaft . As the coupling sleeve is displaced from an initial lock to a locking layer, the toothed portion of the coupling sleeve also engages a toothed portion of the gear on the main shaft.

The coupling sleeve thus establishes a rotationally fixed connection between the carrier and the gear so that the gear receives a rotational load on the main shaft.

A known method which ensures that the coupling sleeve is retained in the loaded layer, when a drive torque is transmitted via the rotationally loaded gear, is to design the axial teeth of the coupling sleeve and the axial teeth of the carrier with angled contact surfaces. When the carrier is opposite a driving torque to the coupling sleeve, a force is created in this case with the aid of the angled contact surfaces which retain the coupling sleeve in the welding layer. Another known method is to provide the teeth of the coupling sleeve with a central portion which projects a short distance in a radial direction. Thus, this portion comes into contact with a front end surface of the carrier's -Lander when a moment is transferred in the gearbox, which means that the coupling sleeve is kept in the welding layer. In both known methods, it is required that spaces are created between the axial teeth of the carrier and the axial wilder of the gear, which are wider than the coupling sleeve Wilder. As a result, a gap is obtained when the torque in the gearbox changes direction. The two methods also require that the coupling sleeve has relatively elongated axial teeth, which increases the total length of the gearbox. SUMMARY OF THE INVENTION The object of the present invention is to provide a welding device which effectively prevents a coupling sleeve from being displaced from a welding layer while occupying a relatively small axial space and enabling the establishment of a substantially loose connection in the gearbox.

To this end, the arrangement of the type mentioned in the introduction is achieved, which is defined by the features stated in the cantilevered part of claim 1. The teeth of the coupling sleeve comprise a load part which is adapted to be inserted into a space between adjacent teeth of the gear unit in the loaded layer. The welding part has a width that increases continuously from a front spirit to a rear spirit. The welding part can then be described as wedge-shaped. The space between the teeth of the gear unit has a width which is continuously from an inner spirit to an opening for receiving the load part.

The space between the teeth of the gear unit can also be referred to as wedge-shaped arms. The front winding, which thus forms the least wide part of the load part, is first pushed into the space via the opening which defines the widest part of the space. It is thus easy to insert the load part into the space when the coupling sleeve and the gear wheel have a synchronous speed. If necessary, the wedge-shaped space provides a centering of the welding part during the insertion process so that it obtains a correct position in the recess as it reaches the fully inserted layer in the space. The fully inserted team is referred to as a lasldge. Since the space has a corresponding width as the welding part both in terms of size and shape, the welding part fills essentially the entire width of the space in the welding sheet.

Thus, there is essentially no play when the torque in the gearbox changes direction. Such a load part has a good function even if it is fairly short. The welding part thus occupies a relatively small axial space in the gearbox.

According to an embodiment of the present invention, the welding part has a width which increases linearly from the front winding to the rear wind. The width of the load section can be defined by two flat side surfaces. As a result, the welding part obtains a relatively simple shape. However, it is possible to provide a load portion having a width that gradually increases from the front end to the rear end in a non-linear manner. In this case, the side surfaces may have a more or less curved shape. The welding part may have a width defined by two side surfaces which are symmetrically arranged on opposite sides of a longitudinal central axis through the respective teeth. The welding part provides the arm with a symmetrical shape which further improves the property of inserting the welding part into the space when the coupling sleeve and the gear wheel have a substantially synchronous speed. With a symmetrical shape of the welding part, the manufacturing process of the teeth of the coupling sleeve is also simplified.

According to an embodiment of the present invention, the teeth of the coupling sleeve comprise a base part which is adapted to remain in a space between two adjacent teeth of the carrier unit in the loaded layer and that the base part comprises at least one side surface which is spaced from a longitudinal central axis by the the teeth, the distance of the side surface to the longitudinal central axis decreasing continuously from a front end to a rear end of the base part. Such a side surface is inclined so that a moment transferred from the wilder of the carrier unit results in a cap which strains to retain the load part in the load layer. As the inclined side surface extends along the entire base part, the base part can be made rather short.

The base part thus occupies a relatively small axial space in the gearbox. The base part can have a corresponding axial tension as the welding part.

According to an embodiment of the present invention, the base part comprises two side surfaces which are symmetrically arranged on opposite sides of a longitudinal central axis through the respective teeth. Thereby two inclined side surfaces are provided where one side surface opposite said force which retains the load part in the load layer when a positive moment is transmitted in the gearbox and a second side surface opposite the said force which retains the load part in the load layer when a negative moment is transmitted in the gearbox.

According to an embodiment of the present invention, the Wilder of the coupling sleeve comprises an intermediate part which is arranged between the welding part and the base part. This intermediate part can be used to bridge the required gap that must be present between the coupling sleeve and the gear unit so that they can rotate at different speeds. Advantageously, said gap and thus the intermediate part has a relatively small axial tension. The intermediate part may have a substantially constant width. The intermediate part can form the widest part of the teeth of the coupling sleeve.

According to an embodiment of the present invention, the teeth of the carrier unit comprise a front part having a width defined by two side surfaces which have an angle to a longitudinal central axis through the respective teeth so that the front 3 part has a width which increases continuously from a front end to a rear spirit. The two side surfaces advantageously have corresponding angles as the angled side surfaces of the base part of the teeth of the coupling sleeve. Thus, the entire side surface of the front part of the teeth of the carrier unit can come into contact with an entire side surface of the base part of the coupling sleeve sand teeth then a moment is transferred to the gearbox. This avoids point loads on the teeth.

According to an embodiment of the present invention, the teeth of the carrier unit comprise a rear part having a width defined by two side surfaces which have an angle to a longitudinal central axis through the teeth of the carrier unit so that the rear part has a width which decreases continuously from a lateral spirit to a rear spirit. In this case, the rear part of the teeth of the carrier unit has a corresponding design as the front part of the teeth of the carrier unit. In some cases, bi-directional lasers are used. In this case, gear units are arranged on both sides of a coupling sleeve. The coupling sleeve can in this case be displaced from an initial bearing in an axial direction to a bearing for one gear unit and in an opposite axial direction to a bearing for the other gear unit. A rear part with the above-mentioned design functions in this case as a front part where a gear unit on the opposite side is to provide a rotational load. If the welding device is unidirectional, the rear part can have any shape. In this case, it can have a constant width.

According to an embodiment of the present invention, the teeth of the carrier unit comprise an intermediate part which is arranged between the front part and the rear part. The intermediate part may have a substantially constant width. The intermediate part can form the widest part of the carrier teeth. The intermediate part of the -Lander of the carrier unit may have a corresponding axial tension as the tension of the intermediate part of the teeth of the coupling sleeve. The intermediate parts can form the contact surface between the teeth of the carrier unit and the -Lander of the coupling sleeve, since the -Lander of the coupling sleeve is in the initial unloaded layer.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, an exemplary embodiment of the invention is described by way of example with reference to the accompanying drawings, in which: Fig. 1 shows a gearbox provided with a welding device according to the present invention, Fig. 2 shows a side view of the welding device Fig. 3 shows the input components of the welding device in a separate state, Fig. 4 shows the input components of the welding device in an initial layer, Fig. 5 shows a sectional view of a connection area between the input components when they are in the initial layer, Figs. Fig. 6 shows the input components of the welding device in an intermediate layer, Fig. 7 shows a sectional view of the connection area between the input components when they are in the intermediate layer, Fig. 8 shows the input components of the welding device in a welding layer and Fig. 9 shows a sectional view of the connection area between the input components as they are in the welding layer.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Fig. 1 shows a gearbox which may be arranged in a schematically indicated vehicle 1.

Vehicle 1 can be a heavy vehicle. Vaxelladan is attached to a house 2 which contains vaxella.dsolja. The gearbox comprises an input shaft 3 which is driven by an internal combustion engine (not shown). The gearbox comprises a side shaft 4 which is provided with a plurality of gears 5-10 of different dimensions. The gears 5-10 are rotatably mounted on the side shaft 4. The gearbox comprises a main shaft 11 which is provided with a plurality of gears 12-17 which are rotatably arranged on the main shaft 11. The gears 5-10 constitute primary gears and the gears 12-17 form secondary gears at the gear pairs which are arranged in engagement with each other in the gearbox. The gearbox is provided with a split shaft which in a first split layer connects the input shaft 3 to the side shaft 4 via a first gear pair 5, 12. In a second split layer the input shaft 3 is connected to the side shaft 4 via a second gear pair 6, 13. The side shaft 4 provides thereby a rotational movement in the two split layers of the input shaft 3. The second pair of gears 6, 13 also provides a gear which defines the gear of the third in the gearbox. The gearbox further comprises a third gear pair 7, 14 defining the second gear in the gearbox, a fourth gear pair 8, 15 defining the one gear in the gearbox, a fifth gear pair 9, 16 defining a creeping gear and a sixth gear 17 defining a pair of gears. a reverse gear. The gear pair 10, 17 for the reverse gear comprises an intermediate gear which provides the reverse direction of rotation of the main shaft 11.

The secondary gears 12-17 are rotatably mounted on the main shaft 11 or the input shaft 3 by means of bearings 18 which may be needle bearings. The locking devices 19-21a according to the invention are arranged in connection with the secondary gears 12-17 on the main shaft 11. Each of the locking devices 19-21a has the task of providing a rotational welding of at least one of the secondary gears 12-17 on the main shaft 11 in connection with loading of a gear. A first load device 19 is included in the split shaft where it has the task of establishing the different split layers so that it connects the input shaft 3 to the side shaft 4 of the gearbox, via the first pair of gears 5, 12 in the first split layer and, via the second pair of gears 6, 13, in the second split team. A second welding device 20 is adapted to be responsible for rotational welding of the secondary gears 13, 14 for the second and third gears. A third welding device 21 is adapted to be responsible for rotational welding of the secondary gear 15 for the gear of one. A fourth welding device 21a is adapted to be responsible for rotational welding of the secondary gears 16, 17 for the creep shaft and the reverse shaft. The gearbox also comprises a range shaft 22 which is arranged between the main shaft 11 and an output shaft 23 of the gearbox. With the aid of a range gear 22, all ordinary gears in the gearbox can be given a hog or a low gear ratio. Thus, the gearbox can receive twice as many gears. A control unit 24a is adapted to activate a maneuvering laser device 24b which controls the activation of the laser devices 19-21 during a shifting process in the gearbox.

Fig. 2 shows a side view of an embodiment of a single-acting welding device corresponding to the welding device 21. Fig. 3 shows the input components of the welding device 21 in a separated condition. Fig. 3 also shows a sectional view of the integral components of a plane AA defined in Fig. 2. The welding device 21 in this case comprises three components, namely a carrier unit 25, a coupling sleeve 26 and a gear unit 27. The carrier unit 25 comprises a radially internal toothed portion 28 with which it is rotatably connected to a toothed portion 11a on the main shaft 11. The carrier unit 25 thus rotates continuously at the same speed as the main shaft 11. The carrier unit 25 comprises a second toothed portion consisting of outwardly directed teeth 29 and intermediate spaces 30 having a axial tensioning The coupling sleeve 26 comprises a toothed portion with food-directed teeth 31 and intermediate cavities 32 having an axial tensioning. The toothed portion 31, 32 of the coupling sleeve 26 is rotatably connected to the toothed portion 29, 30 of the carrier unit 25, thus the coupling sleeve 26 rotates continuously at the same speed as the carrier unit 25 and the main shaft 11. Since the toothed portion of the carrier unit 25 and the toothed portion 26 of the coupling sleeve 26 comprise cooperating teeth 29, 31 and intermediate spaces 30, 32 with an axial tension, the coupling sleeve 26 can be displaced in an axial direction relative to the carrier unit 25. The gear unit 27 comprises the secondary gear 15 and a side part provided with a toothed portion consisting of outwardly directed teeth 33 and intermediate spaces 34 having an axial tension. The toothed portions of the carrier 25, the coupling sleeve 26 and the gear unit 27 have the same number of axial teeth 29, 31, 33 and intermediate spaces 30, 32, 34. They are also arranged at a corresponding radial distance from a longitudinal central axis 1 lb of the main shaft 11. The coupling sleeve 26 can be displaced in an axial direction in relation to both the drive unit 25 and the gear unit 27.

Fig. 4 shows the input components 25-27 in an initial layer. The carrier unit 25 is not visible in this case because it is arranged radially inside the coupling sleeve 26. The carrier unit 25 and the coupling sleeve have the same extent in an axial direction. The carrier unit 25 and the coupling sleeve 26 are arranged at a smaller axial distance from the toothed portion 33, 34 of the gear unit 27. The gear unit 27 and the gear 15 can thus rotate freely in relation to the coupling unit 26, the carrier unit 25 and the main shaft 11. Fig. 5 shows a detailed section a connection area between the components 25, 26, 27 when they are in the initial layer. The axial teeth 29 of the carrier unit 25 have a front part 29a, an intermediate part 29b and a rear part 29c. The front portion 29a has a stretch between a front end 29d in the form of a flat end face and a rear end 29e indicated by a dashed line in the figures. The teeth 29 have side surfaces 29f which have a symmetrical extension in relation to a central longitudinal axis 29g through the teeth 29. The distance of the side surfaces 29f to the central axis 29g increases continuously from the front spirit 29a to the rear spirit 29e. The width of the teeth 29 thus increases continuously from the front spirit 29a to the rear spirit 29e. The intermediate portion 29b has a stretch between the rear end 29e of the front portion 29a and a front end 29h of the rear portion 29c. The distance of the side surfaces 29d to the central axis 29e is constant. The teeth 29 thus have a constant width in the intermediate part 29b. The rear portion 29c has a stretch between the front end 29h and a rear end 29i. The distance of the side surfaces 29f to the central axis 29g 7 decreases continuously from the front end 29h to the rear end 29i. The width of the teeth 29 thus decreases continuously from the front spirit 29h to the rear spirit 29i.

The axial teeth 31 of the coupling sleeve 26 have a welding part 31a, an intermediate part 31b and a base part 29c. The welding part 31a has a stretch between a front end 31d in the form of a flat end surface and a rear end 31e which is indicated by a dashed line. The teeth 31 have side surfaces 31f which have a symmetrical extension in relation to a central longitudinal axis 31g through the teeth 31. The distance of the side surfaces 31f to the central axis 31g increases continuously from the front spirit 31a to the rear spirit 31e.

The width of the teeth 31 thus increases continuously from the front spirit 31a to the rear spirit 31e. The intermediate part 31 has a stretch between the rear end 31e of the welding part 31a and a front end 31h of the base part 31c. The distance of the side surfaces 31f to the central axis 31g is constant. The teeth 31 thus have a constant width in the intermediate part 31b. The babe portion 31c has a stretch between a front end 31f indicated by a dashed line and a rear end 31i in the form of a flat end face. The distance of the side surfaces 31f to the central axis 31g decreases continuously from the front end 31f to the rear end 31i. The width of the teeth 31 thus decreases continuously from the front spirit 31f to the rear spirit 31i.

The axial teeth 33 of the gear unit 27 define an intermediate space 34 which comprises an opening 34a, a bottom surface 34b and side surfaces 34c. The axial distance from the opening 34a to the bottom surface 34b corresponds to the axial length of the welding part 31a. The side surfaces 34c spaced from a central longitudinal axis 34d in the space 34 continuously increase from the bottom surface 34a to the opening 34a. The width of the space 34 then increases continuously from the bottom surface 34b to the opening 34a.

Since the gear 15 is to provide a rotational load on the main shaft 11, a synchronous speed is initially created between the gear 15 and the main shaft 11. During an upshift process, the control unit 24a can activate a braking unit (not shown) which decelerates the side shaft 4 until the gear 15 receives a main axis. During a downshift process, a drive motor is provided which provides an acceleration of the side shaft 4, via the input shaft 3 to the gearbox, until the gear 15 obtains a synchronous speed with the main shaft 11. The control unit 24a can then activate the maneuvering device 24b, which may include a pneumatic cylinder, is responsible for the displacement movement of the coupling sleeve 26 from the initial layer to a welding layer. Figs. 6 and 7 show the coupling sleeve shortly after the said displacement movement has started. The carrier unit 25 is in its fixed axial bearing while the coupling sleeve 26 has started its axial displacement movement. The front end 31d of the welding part 31d of the teeth 31 of the coupling sleeve thus has a smaller width than the opening 34a of the recess in the gear unit 37. There is therefore generally no obligation to insert the welding part 31a into an opening 34a between the gear unit 37 teeth 33 when a synchronous speed is reached. Since the recess 34 has side surfaces 34c inclined in relation to the longitudinal central axis 34d, the side surfaces 34c provide, if necessary, a successive centering of the front end 31d of the welding part 31a during the displacement movement into the space 34.

Figs. 8 and 9 show the teeth 31da of the coupling sleeve, the front spirit 31d of the welding part 31a has an inner spirit 34b defined by an inner end surface in the space 34. The welding part is now in a welding position. Since the space 34 and the welding part 31d have a corresponding width, the welding part 31a fills substantially the entire width of the space 34 in the welding layer. As a result, substantially no play is obtained in the welding device 21 in the connection between the coupling sleeve 26 and the gear unit 27. The intermediate part 31b has an axial length which substantially corresponds to the axial distance between the carrier 25 and the gear unit 27. The base part 31c of the coupling sleeve remains in the recess 30 between the teeth 29 of the carrier unit 29. The base part 31c of the coupling sleeve has side surfaces 31f with a corresponding inclination as the side surfaces 29f of the front part 29a of the carrier. Thus, a moment can be transmitted from the carrier 25 to the coupling sleeve 26 via said side surfaces 29f, 31f. When the teeth 29 of the carrier are opposite a moment to the teeth 31 of the coupling sleeve via said side surfaces 29f, 31f, a force is obtained which retains the teeth 31 of the coupling sleeve in the welding layer in the recess 34.

The rear part 29c of the carrier has in this case a corresponding shape as the front part 29a. The welding device 21 can in this case be double-acting if it is arranged between two gears as is the case with the welding devices 19, 20.

The loading devices 19-21 may, in addition to the function of providing a rotational lasing of the secondary gears 12-15 on the main shaft 11, also have the function of synchronizing the speed of the secondary gears with the speed of the main shaft 11 before the secondary gears provide a rotational lasing on the main shaft 11. In this case A carrier and a ratchet cone (not shown) comprising a conically shaped friction surface. The spar cone in this case comprises the axial teeth 29 of the carrier unit 29. The synchronizing cone can be rotatably connected to the carrier 9 via a toothed connection so that they rotate as a unit. The gear unit 27 comprises the gear 15 and a clutch disc (not shown) with a conically shaped friction surface. The clutch plate can be rotatably connected to the gear via a toothed connection so that they rotate as a unit. The clutch plate in this case comprises the axial teeth 33 of the gear unit 27.

When a gear is to be inserted into the gearbox, in this case the coupling sleeve 26 is displaced in an axial direction from the initial layer to a synchronizing layer in which the conical friction surface of the ratchet cone engages with the conical friction surface of the coupling disc. Thus, the clutch disc and the ratchet cone relatively soon receive a synchronous speed. When the synchronous speed has been reached, the coupling sleeve 26 can be displaced a further distance to the welding layer in which the toothed portion 31, 32 of the coupling sleeve 26 creates a torsionally fixed connection between the carrier unit 25 and the toothed portion 33, 34 so that the gear 15 receives a rotational load on the main shaft 11.

The invention is not limited to the embodiment described above, but it can be varied freely within the scope of the patent claims.

Claims (14)

A welding device (21) for loading a gear (15) on a rotatable shaft (11) in a gearbox, the welding device (21) comprising - a carrier unit (25) comprising a torsionally fixed connection (28, 11a) with the rotatable shaft (11) so as to rotate at a common speed and a toothed portion comprising teeth (29) with intermediate spaces (30) which have an axial tension in relation to the shaft (11), A coupling sleeve (26) comprising in a toothed portion, comprising teeth (31) with intermediate spaces (32) which have an axial tension in relation to the shaft (11), the toothed portion (31, 32) of the coupling sleeve being adapted to be in constant engagement with the toothed portion (29, 30) of the carrier and 2. a gear unit (27) comprising a toothed portion comprising teeth (33) with intermediate spaces (34) which have an axial tension in relation to the shaft (11 ), the coupling sleeve (26) being slidably arranged in an axial direction between an initial bearing in which the toothed portion (29, 30) of the coupling sleeve engages only with the toothed portion (31, 32) of the carrier unit and a load bearing in which the coupling sleeve (26) toothed portion (31, 32) engages both the toothed portion (29, 30) of the carrier unit and the toothed portion (33, 34) of the gear unit, characterized in that each of the teeth (31) of the coupling sleeve comprises a welding part (31a) which is adapted to is inserted into a space (34) between adjacent teeth (33) of the gear unit (27) in the loaded layer, said welding part (31a) having a stretch between a front end (31d) which in the welding layer is adapted to be arranged in connection with an inner spirit (34b) of the space (34) and a rear spirit (31e) adapted in the welding layer to be arranged adjacent to an opening (34a) of the space (34), and the welding part (31a) having a width which increases continuously from the front spirit (31d) to the rear spirit (31e) and that the space (34) has a corresponding width as the welding part (31a) both in size and shape so that the welding part (31a) fills substantially the entire width of the space (34) in the council. Welding device according to claim 1, characterized in that the welding part (31a) comprises two side surfaces (310 defining the width of the welding part and that said side surfaces (310 have an inboard slope so that the width of the welding part increases linearly from the front spirit (31d) to the rear spirit (31e) .11 Welding device according to claim 2, characterized in that the two side surfaces (310) of the welding part (31a) are symmetrically arranged on opposite sides of a longitudinal central axis (31g) through the respective teeth (31). A welding device according to any one of the preceding claims, characterized in that the teeth (31) of the coupling sleeve comprise a base part (31c) which is adapted to remain in a space (30) between two adjacent teeth (29) of the carrier unit (25) in the loaded layer and that the base part (31c) comprises at least one side surface (31f) which is spaced from a longitudinal central axis (31g) by the respective teeth (31), the distance of the side surface to the central axis (31g) decreasing continuously from a front end (31h) to a rear end (31i) of the base portion (31c). Welding device according to claim 4, characterized in that the base part (31a) comprises two side surfaces (310 which are symmetrically arranged on opposite sides of a longitudinal central axis (31g) through the respective teeth (31). Welding device according to claim 5, characterized in that the teeth (31) of the coupling sleeve comprise an intermediate part (31b) which is arranged between the welding part (31a) and the babe part (31c). Welding device according to hay 6, characterized in that the intermediate part (3 lb) has a substantially constant width. Welding device according to any one of the preceding bay, characterized in that the teeth (29) of the carrier unit (25) comprise a front part (29a) having a width defined by two side surfaces (29f) which have an angle to a longitudinal central axis (29g). ) through the respective teeth (29) so that the front part (29a) obtains a width which increases continuously from a front end (29d) to a babe spirit (29e). A lasing device according to any preceding bay, characterized in that the teeth (29) of the carrier unit comprise a babe portion (29c) having a width defined by two side surfaces (291) having an angle to a longitudinal central axis (29g) so that the babe part (29c) has a width which decreases continuously from a front spirit (29h) to a babe spirit (29i). 12 Welding device according to claim 8 or 9, characterized in that the teeth (29) of the carrier unit comprise an intermediate part (29b) which is arranged between the front part (29a) and the rear part (29c). Welding device according to claim 10, characterized in that the intermediate part (29b) has a substantially constant width. A locking device according to any one of the preceding claims, characterized in that the carrier unit (25) comprises a carrier which is in constant engagement with the shaft (11) and a first synchronizing unit which comprises the toothed portion (29, 30) of the carrier unit, and that the gear unit (27) comprises a gear (15) and a second synchronizing unit comprising the toothed portion (33, 34) of the gear unit. Gearbox comprising a welding device according to any one of the preceding claims 1-12. Vehicle comprising a gearbox according to claim 13. 13 1 K-24b 2ga „, oak, 12 19 1314 21 1617 1I / 24a 2 23 11b 22 7 10