Steering drive

Abstract

Steering drive for a wheel drive of a transport device that is pivotable about a vertical steering axis (3), comprising a connecting plate (2) arranged on a component of the transport device, on which a hub carrier plate (25) of a hub carrier housing (5) of a wheel (7) that is pivotally driven about the vertical steering axis (3) by a steering motor and parallel to the connecting plate (2) is pivotally mounted by means of a bearing arrangement (4), characterized in that the connecting plate (2) has, on its side facing the hub carrier plate (25), one or more first rolling element raceways (11) coaxial with the steering axis (3), and the hub carrier plate (25) has, on its side facing the connecting plate (2), second rolling element raceways (11') opposite and corresponding to the rolling element raceways (11), wherein a plurality of rolling elements protrude into the first and second rolling element raceways (11, 11') and are carried out in these.

Description

[0001] The invention relates to a steering drive for a wheel drive of a transport device which can be pivoted about a vertical steering axis, with a connecting plate arranged on a component of the transport device, on which a hub carrier plate of a hub carrier housing of a wheel which can be driven pivotably about the vertical steering axis by a steering motor and is parallel to the connecting plate is pivotally mounted by means of a bearing arrangement.

[0002] In such steering drives, the bearing arrangements are typically designed as radial ball bearings. In order for these bearing arrangements to be able to absorb high forces in a predominantly vertical direction, they must be very strong and massive, making them complex and expensive.

[0003] DE 10 2006 023 303 A1 describes a drive device for an industrial truck with a motor housing which is fixedly connected to an outer ring of a slewing ring bearing and has a recess through which a component protrudes, by means of which a rotary movement can be introduced onto the gear housing.

[0004] DE 10 2009 047 730 A1 discloses a steerable drive assembly for an industrial truck. The drive assembly comprises at least one drive motor coupled to a drive wheel of the vehicle via an angular gear, and at least one steering motor coupled to at least one internally toothed slewing ring via a steering gear for transmitting a steering movement. The slewing ring is mounted on the vehicle frame of the industrial truck via a slewing ring for rotation about a vertical axis. The drive motor and the steering motor are arranged side by side with respect to the vertical axis. The steering gear is arranged at least radially substantially within the slewing ring.

[0005] The generic document DE 10 2021 204 110 A1 relates to a steering drive for a wheel drive of a transport device that can pivot about a vertical steering axis, comprising a connecting plate fixedly mounted on a component of the transport device, on which a hub carrier housing of a wheel, which can be driven pivotably about the steering axis by a steering motor, is pivotally mounted by means of a bearing arrangement. The bearing arrangement has a first tapered roller bearing and a second tapered roller bearing, which are arranged concentrically to the steering axis in an O-arrangement. The connecting plate is supported vertically downwards on the inner ring of the first tapered roller bearing, which is supported radially inwardly directly or indirectly on a first annular wall of the connecting plate.The inner ring of the first tapered roller bearing, in turn, is supported vertically downwards on the hub carrier housing via the tapered rollers and the outer ring of the first tapered roller bearing, with the outer ring of the first tapered roller bearing being supported on a radially encircling second annular wall of the hub carrier housing. An inner ring of the second tapered roller bearing is clamped vertically upwards against the connecting plate and supported radially inwardly on the connecting plate or a component connected to the connecting plate. Its outer ring is loaded vertically downwards by the hub carrier housing and supported radially outwardly.

[0006] The object of the invention is to provide a steering drive of the type mentioned above which has a simple structure and can absorb high axial forces in the vertical direction.

[0007] This object is achieved according to the invention in that the connecting plate has, on its side facing the hub carrier plate, one or more first rolling element raceways coaxial with the steering axis, and the hub carrier plate has, on its side facing the connecting plate, second rolling element raceways opposite and corresponding to the first rolling element raceways, wherein a plurality of rolling elements protrude into the first and second rolling element raceways and are guided in these.

[0008] Due to this design, the hub carrier plate, connecting plate and rolling elements take over the function of the bearing arrangement, which leads to a simple structure.

[0009] Since the rolling element raceways are optimally arranged to absorb vertical forces, significantly softer materials and surface qualities can be selected for the hub carrier plate and the connecting plate, thus achieving a very cost-effective design.

[0010] The rolling element raceways preferably have a semicircular cross-section and the rolling elements are balls, which results in a particularly simple design.

[0011] If forces are introduced into the bearing arrangement via the wheel in unfavourable directions, lifting of the rolling element raceways from the rolling elements is prevented by the hub carrier plate and the connecting plate being connected to each other by a lifting device which allows them to rotate relative to each other and around the steering axis and prevents them from moving away from each other axially.

[0012] In order to enable relative rotation between the hub carrier plate and the connecting plate, the hub carrier plate can be connected to the connecting plate via an axial bearing, whereby the axial bearing can be a rolling bearing.

[0013] However, for a simple design, it is also possible for the axial bearing to be a plain bearing.

[0014] For this purpose, a ring-like sliding surface can be arranged in a simple manner on the hub carrier plate or on a component firmly connected to the hub carrier plate at right angles and coaxially to the steering axis, which ring engages around a retaining ring arranged on the connecting plate and is in axial contact therewith.

[0015] To reduce friction, the sliding surface is advantageously axially in contact with the retaining ring via an annular thrust washer, whereby the thrust washer can be arranged on the connecting plate in a rotationally secured manner.

[0016] Embodiments of the invention are illustrated in the drawings and described in more detail below. They show: Fig. 1 a longitudinal section of a steering drive Fig. 2 a section of the steering drive according to Fig. 1.

[0017] The steering drive shown in the figures has a connecting plate 2 fixedly arranged on a vehicle frame 1 of a transport device, on which a hub carrier housing 5 is arranged so as to be pivotable about a vertical steering axis 3 by means of a bearing arrangement 4.

[0018] For this purpose, the hub carrier housing 5 has at its upper end a hub carrier plate 25 with a radially rotating steering gear rim 6, into which a drive pinion (not shown) of a steering drive arranged on the connecting plate 2 engages.

[0019] A wheel 7 is rotatably mounted on the hub carrier housing 5 about a wheel axle 8 extending at right angles to the steering axle 3, wherein the wheel axle 8 carries a gear 9 which can be rotatably driven by a drive motor 24 arranged on the vehicle frame 1 via a drive train 10.

[0020] The horizontal connecting plate 2 has, on its side facing the likewise horizontal hub carrier plate 25, two first rolling element raceways 11 of semicircular cross-section concentrically arranged to one another, which are opposite the corresponding second rolling element raceways 11 in the hub carrier plate 25. A plurality of balls 12 are arranged and guided in the rolling element raceways 11, 11'.

[0021] In order to prevent the rolling element raceways 11, 11' from lifting off the balls 12, the hub carrier plate 25 is connected to the connecting plate 2 by a lifting protection device 13 so that it can rotate relative to one another about the steering axis 3 and is also connected to one another so that they cannot move away from one another axially.

[0022] The hub carrier plate 25 is preloaded against the connecting plate 2 by the anti-lift device 13 via the balls 12.

[0023] The anti-lift device 13 has an anti-lift ring 15 which is fastened to the hub carrier plate 25 concentrically to the steering axis 3 by a screw connection 14, wherein the anti-lift ring 15 has a radially inwardly projecting ring shoulder 16 at its end region facing the connecting plate 2.

[0024] The connecting plate 2 has a pipe socket 17 on its radially inner area, which projects through the ring extension 16.

[0025] In its area protruding through the ring shoulder 16, the pipe socket 17 has a radially circumferential annular groove 18 on its outer surface, into which a retaining ring 19 is inserted.

[0026] Between the retaining ring 19 and the annular surface 20 of the annular shoulder 16 facing away from the connecting plate 2, an annular thrust washer 21 is arranged axially free of play in such a way that an axial bearing 28 is formed and the hub carrier plate 25 and the connecting plate 2 cannot move axially away from each other but are rotatably clamped against each other via the balls 12.

[0027] To secure the thrust washer 21 against rotation, it has a shoulder 22 which projects radially inward into an axial groove 23 in the pipe socket 17.

[0028] A drive shaft 26 of the drive motor 24 with a spur gear 27 projects through the pipe socket 17, via which the drive train 10 and the wheel 7 of the transport device can be driven in rotation. Reference symbol 1 vehicle frame 2 connection plate 3 steering axle 4 Bearing arrangement 5 hub carrier housing 6 steering gear 7 wheel 8 wheel axle 9 gear 10 Drivetrain 11 first rolling element raceways 11' second rolling element raceways 12 balls 13 Lift-off protection 14 screw connection 15 Anti-lift ring 16 ring attachment 17 pipe sockets 18 ring groove 19 Retaining ring 20 ring area 21 Thrust washer 22 Approach 23 Axial groove 24 drive motor 25 Hub carrier plate 26 Drive shaft 27 Spur gearing 28 thrust bearings

Claims

[1] Steering drive for a wheel drive of a transport device which can be pivoted about a vertical steering axis (3), with a connecting plate (2) arranged on a component of the transport device, on which a hub carrier plate (25) of a hub carrier housing (5) of a wheel (7) which can be driven by a steering motor so as to be pivotable about the vertical steering axis (3) and is parallel to the connecting plate (2) is pivotally mounted by means of a bearing arrangement (4), characterized by that the connecting plate (2) has, on its side facing the hub carrier plate (25), one or more first rolling element raceways (11) coaxial with the steering axis (3), and the hub carrier plate (25) has, on its side facing the connecting plate (2), second rolling element raceways (11') opposite and corresponding to the rolling element raceways (11), wherein a plurality of rolling elements protrude into the first and second rolling element raceways (11, 11') and are guided in these. [2] Steering drive according to claim 1, characterized bythat the rolling element raceways (11, 11') have a semicircular cross-section and the rolling elements are balls (12). [3] Steering drive according to one of the preceding claims, characterized by that the hub carrier plate (25) and the connecting plate (2) are connected to one another by a lifting lock (13) so that they can rotate relative to one another about the steering axis (3) and are prevented from moving away from one another axially. [4] Steering drive according to claim 3, characterized by that the hub carrier plate (25) is preloaded against the connecting plate (2) by the lifting device (13) via the rolling elements. [5] Steering drive according to one of the preceding claims 3 and 4, characterized by that the hub carrier plate (25) is connected to the connecting plate (2) via an axial bearing (28). [6] Steering drive according to claim 5, characterized by that the axial bearing (28) is a rolling bearing. [7] Steering drive according to claim 5, characterized bythat the axial bearing (28) is a plain bearing. [8] Steering drive according to claim 7, characterized by that an annular sliding surface (20) is arranged on the hub carrier plate (25) or on a component firmly connected to the hub carrier plate (25) at right angles and coaxially to the steering axis (3), which sliding surface engages around a retaining ring (19) arranged on the connecting plate (2) and is in axial contact therewith. [9] Steering drive according to claim 8, characterized by that the sliding surface (20) is axially in contact with the retaining ring (19) via an annular thrust washer (21). [10] Steering drive according to claim 9, characterized by that the thrust washer (21) is arranged on the connecting plate (2) in a rotationally secured manner.

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