Electrically operated differential lock

Abstract

The invention relates to an electrically actuated differential lock for a differential of a vehicle axle consisting of two coaxial wheel shafts 3 rotatably driven about a pivot axis 6 and comprising an axle bridge housing 1). One of the wheel shafts 3 is non-rotatably connected to the differential carrier 5 of the differential by means of a coupling device 4. The differential carrier 5 has a non-rotatably connected first coupling ring, with its first coupling side facing away from the differential, coaxially to the pivot axis 6 of one wheel shaft 3. A locking slide 14 is non-rotatably guided coaxially on one wheel shaft 3 and has a corresponding second coupling side of a second coupling ring facing towards the first coupling side.The locking slide 14 can be driven by an electric motor to adjust between an out-of-engagement position of the first and second coupling sides from each other and an in-engagement position of the first and second coupling sides into each other.

Description

[0001] The invention relates to an electrically actuated differential lock for a differential of a vehicle axle consisting of two coaxial wheel shafts rotatably driven about a pivot axis and having an axle bridge housing, wherein one of the wheel shafts can be connected to the differential basket of the differential in a rotationally fixed manner by means of a coupling device and the differential basket has a rotationally fixed first coupling ring with a first coupling side facing away from the differential, coaxially to the pivot axis of one wheel shaft and a locking slide is arranged on one wheel shaft in a rotationally fixed manner and is coaxially displaceable, the locking slide having a corresponding second coupling side of a second coupling ring facing towards the first coupling side.wherein the locking slide can be adjusted by electric motor between an out-of-engagement position of the first and second coupling sides from each other and an in-engagement position of the first and second coupling sides interlocked.

[0002] From DE 199 42 532 A1, an electromechanical differential lock of the type mentioned above is known. In this design, the electromechanical drive is located outside the gearbox housing. All other components up to the clutch assembly are located outside the gearbox housing and can therefore be affected by contamination and mechanical influences.

[0003] The object of the invention is to create an electrically actuated differential lock of the type mentioned above, which has a simple design with low component requirements, is protected from external impairments, requires little installation space and has only low energy consumption.

[0004] This problem is solved according to the invention by arranging a threaded ring rotatably driven in both directions of rotation in a housing opening of the axle bridge housing that is coaxial with a wheel shaft, the threaded ring having an axial thread on its radially circumferential surface which engages in a corresponding nut thread of the housing opening, wherein the locking slide can be actuated by the threaded ring into the engaged position as well as into the disengaged position.

[0005] This design, requiring only a few components, allows the differential lock to be positioned inside the axle bridge housing and thus protected from external interference.

[0006] Multiple use of components results in a lower component requirement.

[0007] The coaxial arrangement surrounding the wheel shaft requires minimal installation space, is lightweight, and has low energy consumption. This extends the service life of the differential lock.

[0008] Compared to a hydraulically actuated differential lock, the advantage is that no conversion of electrical to hydraulic energy is required, thus reducing weight, size and components.

[0009] The coupling device can be any suitable coupling device, such as a friction clutch.

[0010] A secure, rotationally fixed connection of one wheel shaft to the differential basket can be achieved by the first coupling ring being a first claw ring that has first claws pointing away from the differential, and the second coupling ring having second claws pointing towards the first claws of a second claw ring forming the second coupling ring.

[0011] To apply axial force to the threaded ring by the locking slide while allowing easy relative rotation of these two parts to each other, an axially load-bearing rolling bearing can be arranged with its outer ring fixed to the threaded ring and with its inner ring fixed to the locking slide.

[0012] Preferably, the rolling bearing is a ball bearing.

[0013] The threaded ring can be guided axially displaceably in the housing opening in the area(s) outside the nut thread of the housing opening. For smooth operation, the guidance can be achieved in sliding rings that are inserted into radially circumferential grooves of the threaded ring and slide along the wall of the housing opening.

[0014] This prevents a tilting moment acting on the threaded ring, even if the threaded ring can be moved easily.

[0015] The threaded ring can have a gear along a portion of its length, into which a drive gear of an electric motor engages. The gear is preferably located at the end of the threaded ring furthest from the differential and can, in particular, be formed integrally with the threaded ring.

[0016] The drive wheel can be rotatably driven by the electric motor drive via a reduction gear in order to keep the duration of the linear movement of the threaded ring short.

[0017] The drive wheel can be a worm wheel that can be rotatably driven about a drive axis extending perpendicular to the axis of rotation of one wheel shaft, whereby the electric motor drive can protrude from the axle bridge housing.

[0018] An arrangement completely within the axle housing of the electric motor drive is achieved by mounting a rotor of an electric motor on an extension of the threaded ring, which is enclosed by a stator of the electric motor that is fixedly mounted within the axle housing. This also protects the electric motor drive against external influences such as dirt and moisture, as well as against damage.

[0019] Exemplary embodiments of the invention are shown in the drawing and are described in more detail below. The drawing shows: Fig. 1 a partial longitudinal section of a first embodiment of an electrically actuated differential lock Fig. 2 a partial longitudinal section of a second embodiment of an electrically actuated differential lock

[0020] The illustrated electromechanical differential locks are arranged in a housing opening 2 of an axle housing 1 of a vehicle axle. A wheel shaft 3, rotatable about a pivot axis 6, passes through the axle housing 1 and leads at one end (not shown) to a vehicle wheel (not shown).

[0021] The other end can be coupled to the differential basket 5 of a differential by means of a coupling device 4.

[0022] The differential basket 5 has on its side facing away from the differential a first claw ring 7 coaxial to the axis of rotation with first claws 8 directed away from the differential, the second claws 9 of a second claw ring 10 of a locking slide 14 opposite, which is driven coaxially on the wheel shaft 3 in a rotationally fixed but coaxially displaceable manner.

[0023] The housing opening 2 is cylindrical in a partial region of its length and has a nut thread 11 in the middle region of the partial region.

[0024] The thread 12 of a radially circumferential threaded ring 13 engages in the nut thread 11, which surrounds the locking slide 14 at a radial distance.

[0025] On both sides of the radially circumferential surface of the threaded ring 13, radially circumferential, radially outwardly open annular grooves 15 are formed at a distance from the thread 12. Sliding rings 16 are inserted into these grooves. The sliding rings 16 guide the threaded ring 13 axially displaceably within the housing opening 2, at least to a large extent without tilting.

[0026] The outer ring 17 of a ball bearing 18 is axially fixed to the inner circumference of the threaded ring 13, while the inner ring 19 of the ball bearing 18 is axially fixed to the locking slide 14.

[0027] The ball bearing 18 can withstand axial loads, so that an axial movement of the threaded ring 13 is transferred to the locking slide 14.

[0028] In the exemplary embodiment of the Fig. 1 The threaded ring 13 has a radially rotating gear 20 at its end facing away from the differential, into which a worm gear 21 engages, which is arranged on the output shaft 23 of an electric motor 22.

[0029] The output shaft 23 of the electric motor 22, which is located outside the axle bridge housing 1, projects at a right angle to the axis of rotation of the wheel shaft 3 through an opening in the axle bridge housing 1 into the interior of the axle bridge housing 1 and carries the gear 20 there.

[0030] In the exemplary embodiment of the Fig. At the end of the threaded ring 13 facing away from the differential, a rotor 24 of an electric motor 22' is arranged, which is enclosed at a radial distance by a stator 25. The stator 25 is arranged in a rotationally fixed manner in the housing opening 2 of the axle bridge housing 1.

[0031] The electric motors 22 and 22' are reversibly driven electric motors.

[0032] During normal vehicle operation, the locking slide 14 is in the disengaged position shown. To lock the differential, the electric motor, and consequently the threaded ring 13, is driven in a first direction of rotation. The rotation of the thread of the threaded ring 13 in the nut thread 11, via the ball bearing 18, moves the locking slide 14 to the left, so that the jaws 8 and 9 of the first and second jaw rings 7 and 10 engage in the engaged position, and the clutch mechanism is closed. The differential is thus locked.

[0033] To unlock, the electric motor and through it the threaded ring 13 are driven in the opposite second direction of rotation and the locking slide 14 is moved to the right into its out-of-engage position. Reference sign 1 axle bridge housing 2. Housing opening 3 Wheel shaft 4 Coupling device 5 Differential basket 6 axis of rotation 7 first claw ring 8 first claws 9 second claws 10 second claw ring 11 nut threads 12 threads 13 Threaded ring 14 locking gates 15 ring grooves 16 sliding rings 17 Outer ring 18 ball bearings 19 inner ring 20 gear 21 worm gear 22 Electric motor 22' electric motor 23 Output shaft 24 Rotor 25 Stator

Claims

[1] Electrically actuated differential lock for a differential of a vehicle axle consisting of two coaxial wheel shafts (3) rotatably driven about a pivot axis (6) and having an axle bridge housing (1), wherein one of the wheel shafts (3) can be connected non-rotatably to the differential basket (5) of the differential by means of a coupling device (4) and the differential basket (5) has a non-rotatably first coupling ring with a first coupling side facing away from the differential, coaxially to the pivot axis (6) of one wheel shaft (3) and a non-rotatably guided locking slide (14) is arranged coaxially displaceably on one wheel shaft (3), the locking slide having a corresponding second coupling side of a second coupling ring facing towards the first coupling side,wherein the locking slide (14) can be driven by an electric motor adjustable between an out-of-engagement position of the first and second coupling sides from each other and an in-engagement position of the first and second coupling sides into each other, characterized by , that in a housing opening (2) of the axle bridge housing (1) which is coaxial to one wheel shaft (3) a threaded ring (13) which can be rotatably driven in both directions of rotation is arranged, which has an axial thread (12) on its radially circumferential surface which engages in a corresponding nut thread (11) of the housing opening (2), wherein the locking slide (14) can be actuated by the threaded ring (13) into the engaged position as well as into the disengaged position. [2] Differential lock according to claim 1, characterized by, that the first clutch ring is a first claw ring (7) having first claws (8) pointing away from the differential and the second clutch ring has second claws (9) pointing towards the first claws (8) of a second claw ring (10) forming the second clutch ring. [3] Differential lock according to one of the preceding claims, characterized by , that an axially loadable rolling bearing is arranged with its outer ring (17) fixed to the threaded ring (13) and with its inner ring (19) fixed to the locking slide (14). [4] Differential lock according to claim 3, characterized by , that the threaded ring (13) is guided axially displaceably in the housing opening (2) in the area(s) outside the nut thread (11) of the housing opening (2). [5] Differential lock according to claim 3, characterized by , that the threaded ring (13) has a gear (20) on a partial section of its length, into which a drive wheel of an electric motor drive engages. [6] Differential lock according to claim 5, characterized by , that the drive wheel can be rotatably driven by the electric motor drive via a reduction gear. [7] Differential lock according to one of claims 3 and 4, characterized by , that the drive wheel is a worm wheel (21) which can be rotatably driven about a drive axis extending perpendicularly to the axis of rotation (6) of one wheel shaft (3). [8] Differential lock according to any one of claims 1 to 4, characterized by , that a rotor (24) of an electric motor (22') is arranged on a projection of the threaded ring (13), which is enclosed by a stator (25) of the electric motor (22') fixedly arranged in the axle bridge housing (1).

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