DRIVE FOR A STEERING AXLE OF AN INDUSTRIAL TRUCK, STEERING AXLE, AND INDUSTRIAL TRUCK

Abstract

A drive (1) for a steering axle (26) of an industrial truck includes two steering arms (11, 12), an axle arch (8), a tie rod (13) configured as a spindle (13), a spindle nut (7) fixed axially on the tie rod (13), and a gear stage (21). Adjustment of the steering arms (11, 12) can be effected by axial displacement of the tie rod (13), and by the spindle nut (7) being able to be driven by a drive output element (7) of the gear stage (21). The drive (1) has two mutually coaxial electric motors (17, 18) disposed parallel to the tie rod (13). A drive element (14) of the gear stage (21) can be driven by the two electric motors (17, 18), which are disposed so as to be axially centric between the two electric motors (17, 18). Also disclosed is a steering axle and an industrial truck.

Claims

1. A drive (1) for a steering axle (26) of an industrial truck, comprising: two steering arms (11, 12); an axle arch (8); a tie rod (13) configured as a spindle (13); a spindle nut (7) fixed axially on the tie rod (13); two mutually coaxial electric motors (17, 18) disposed parallel to the tie rod (13); and a gear stage (21) having a drive element (14) configured to be driven by the two electric motors (17, 18), the gear stage being disposed axially centric between the two electric motors (17, 18); wherein an adjustment of the two steering arms (11, 12) can be effected by an axial displacement of the tie rod (13), and by the spindle nut (7) being able to be driven by a drive output element (7) of the gear stage (21).

2. The drive (1) as claimed in claim 1, wherein the spindle nut (7), the gear stage (21), and the two electric motors (17, 18) are encased by a common housing (6).

3. The drive (1) as claimed in claim 1, wherein the two electric motors (17, 18) are disposed symmetrically about a central axis (23) of the axle arch (8).

4. The drive (1) as claimed in claim 1, wherein the two electric motors (17, 18) have a common motor shaft (15) and the drive element (14) of the gear stage (21) is disposed so as to be axially centric and rotationally fixed on the common motor shaft (15).

5. The drive (1) as claimed in claim 4, wherein the common motor shaft (15) by way of mountings (16, 19, 24, 25) is rotatably mounted so as to be axially between the two electric motors (17, 18) or axially outside the two electric motors (17, 18).

6. The drive (1) as claimed in claim 1, wherein the two electric motors (17, 18) have two motor shafts (15, 15′), the drive comprising a coupling (14) connecting the two motor shafts (15, 15′) in a rotationally fixed manner, and the drive element (14) of the gear stage (21) being disposed so as to be rotationally fixed on the coupling (14).

7. The drive (1) as claimed in claim 6, wherein the coupling (14) is rotatably mounted in the housing (6) by way of mountings (30, 31), the coupling (14) representing the drive element (14).

8. The drive (1) as claimed in claim 1, wherein the gear stage (21) is configured as a spur wheel stage (21), the spindle nut (7) having an external toothing which represents the drive output element (7).

9. The drive (1) as claimed in claim 1, wherein the gear stage (21) is configured as a traction mechanism (21), the spindle nut (7) having an external running face which represents the drive output element (7).

10. A steering axle (26) for an industrial truck, comprising: two steerable wheels (2, 3); and the drive (1) of claim 1 for the steering axle (26).

11. The steering axle (26) as claimed in claim 10, wherein the two electric motors (17, 18) are disposed at a height level of the axle arch (8) and behind the axle arch (8) in the travel direction of the steering axle (26).

12. An industrial truck, comprising a steering axle (26) as claimed in claim 10.

13. The drive (1) of claim 1, wherein the two electric motors (17, 18) are disposed symmetrically about the central axis (23) of the axle arch (8).

14. The drive (1) of claim 13, comprising: first and second motor shafts (15, 15′); a coupling (14) connecting the first and second motor shafts (15, 15′) in a rotationally fixed manner; wherein the drive element (14) of the gear stage (21) is rotationally fixed on the coupling (14).

15. The drive (1) of claim 14, wherein the coupling (14) is rotatably mounted in the housing (6) by way of mountings (30, 31).

16. The drive (1) of claim 13, wherein the two electric motors (17, 18) have a common motor shaft (15) and the drive element (14) of the gear stage (21) is disposed so as to be axially centric and rotationally fixed on the common motor shaft (15).

17. The drive (1) of claim 16, wherein the common motor shaft (15) is rotatably mounted so as to be axially between the two electric motors (17, 18).

18. The drive (1) of claim 16, wherein the common motor shaft (15) is rotatably mounted so as to be axially outside the two electric motors (17, 18).

19. The drive (1) of claim 16, wherein the gear stage (21) is configured as a spur wheel stage (21).

20. The drive (1) of claim 16, wherein the gear stage (21) is configured as a traction mechanism (21).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention will be explained in an exemplary manner hereunder by means of embodiments illustrated in the figures.

[0041] In the figures:

[0042] FIG. 1 shows in an exemplary and schematic manner a potential embodiment of a steering axle according to the invention, having a drive according to the invention, in a plan view from above;

[0043] FIG. 2 shows the steering axle of FIG. 1, having a maximum steering angle toward the right;

[0044] FIG. 3 shows in an exemplary and schematic manner a further potential embodiment of a steering axle according to the invention, having a drive according to the invention in the steering angle position already shown in FIG. 2; and

[0045] FIG. 4 shows in an exemplary and schematic manner a further potential embodiment of a steering axle according to the invention, having a drive according to the invention in the steering angle position already shown in FIG. 2.

[0046] Identical items, functional units and equivalent components are provided with the same reference signs in all of the figures. These items, functional units and equivalent components are identically embodied in terms of the technical features thereof, unless otherwise explicitly or implicitly derived from the description.

DETAILED DESCRIPTION

[0047] FIG. 1 shows in an exemplary and schematic manner a potential embodiment of a steering axle 26 according to the invention, having a drive 1 according to the invention, in a plan view from above. The steering axle 26 is provided for use in an industrial truck (not illustrated in FIG. 1). The steering axle 26 comprises two steering arms 11 and 12, an axle arch 8, a tie rod 13 configured as a spindle 13, a spindle nut 7 fixed axially on the tie rod 13, and a gear stage 21. The gear stage 21 comprises a drive element 14, which is configured as a drive wheel 14 for a belt drive, and the spindle nut 7 which according to the example by way of a corresponding external running face is configured as a drive output element 7 for the belt drive and by way of a timing belt 20 is operatively connected to the drive element 14 configured as the drive wheel 14. The steering axle 26 furthermore comprises two mutually coaxial electric motors 17 and 18 which are aligned so as to be parallel to the tie rod 13. Finally, the steering axle 26 also comprises a common housing 6 which is fixedly disposed on the axle arch 8 and encases the two electric motors 17, 18 and the gear stage 21, mounting in each case the two electric motors 17, 18 and the gear stage 21 by way of mountings 28, 29, 16 and 19.

[0048] As can be seen in FIG. 1, the steerable wheels 2 and 3 according to the example are not turned. Accordingly, their axes 4 and 5 are mutually parallel or identical, respectively. The housing 6 receives the spindle nut 7 in such a manner that the spindle nut 7 is mounted in the housing 6 so as to be rotatable about the axis 22 but is immovable in the axial direction. A rotating movement of the spindle nut 7 is converted into an axial movement of the spindle 13, the latter transmitting the movement to the steering arms 11 and 12 and thus to the axle journals 9 and 10 that are rotatably mounted in the axle body 8. The wheels 2 and 3, which are mounted so as to be rotatable about the axes 4 and 5, are fastened to the axle journals 9 and 10 and are pivoted conjointly with the latter. The spindle nut 7 as the drive output element 7 of the gear stage 21 is driven, the latter being configured according to the example as a traction mechanism 21.

[0049] The two electric motors 17 and 18 have a common motor shaft 15, the drive element 14 being disposed so as to be a rotationally fixed in the axial center between said two electric motors 17 and 18. The motor shaft 15 by way of the mountings 16 and 19 is rotatably mounted in the housing 6. The electric motors 17, 18 per se are in each case held so as to be rotationally fixed in the housing 6. Moreover, the motor shaft 15 supports the rotors 17′ and 18′ of the electric motors 17 and 18. The electric motors 17 and 18 are disposed so as to be symmetrical in relation to the central axis 23 of the industrial truck not illustrated. The drive element 14 is disposed so as to be centric between the rotors 17′ and 18′.

[0050] The travel direction of the steering axle 26 here is illustrated by an arrow 27 in FIG. 1. The two electric motors 17 and 18 in the travel direction of the steering axle 26 are disposed at the same height level as the axle arch 8, so as to be behind the axle arch 8.

[0051] FIG. 2 shows the steering axle 26 of FIG. 1, having a maximum steering angle toward the right. FIG. 2 visualizes that the installation space available for the drive 1 is very limited, in as far as said drive 1 is not to restrict the steering angle range of the wheels 2 and 3. The available installation space here, without the latter restricting the steering angle range of the wheels 2 and 3, is delimited by an envelope of the movement of the wheels 2 and 3 (not illustrated in FIG. 2). The drive output required for steering is divided among the electric motors 17 and 18, the latter being in each case able to be embodied smaller than if only a single electric motor were to be used for the drive of the steering axle 26. The symmetrical disposal of the spindle nut 7 and of the electric motors 17 and 18 in relation to the central axis 23 of the steering axle 26 enables a maximum stroke of the spindle 13 in the spindle nut 7 toward the left or the right, respectively, without restricting the steering angle position of the wheels 2 and 3. The electric motors 17 and 18 utilize the available installation space to the optimum.

[0052] FIG. 3 shows in an exemplary and schematic manner a further potential embodiment of a steering axle 26 according to the invention, having a drive 1 according to the invention, in the steering angle position already shown in FIG. 2. The steering axle 26 illustrated in FIG. 3 differs from the steering axle of FIG. 2 or FIG. 1, respectively, in terms of the mounting of the motor shaft 15. Instead of mountings 16 and 19 at the axial ends of the motor shaft 15, the latter is rotatably mounted by mountings 24 and 25. The mountings 24 and 25 here are disposed on both sides on the motor shaft 15 so as to be directly adjacent to the drive element 14. In this way, forces of the teeth or the belts of the gear stage 21 can be reduced.

[0053] FIG. 4 shows in an exemplary and schematic manner a further potential embodiment of a steering axle 26 according to the invention, having a drive 1 according to the invention, in the steering angle position already shown in FIG. 2. The steering axle 26 of FIG. 4 here has two individual motor shafts 15, 15′. The motor shaft 15 is assigned to the electric motor 17, and the motor shaft 15′ is assigned to the electric motor 18. The motor shafts 15 and 15′ are connected in a rotationally fixed manner to the drive element 14, the latter being configured as a coupling 14 for the driveshafts 15, 15′. The motor shaft 15 transmits the drive output of the electric motor 17 to the drive element 14, and the motor shaft 15′ transmits the drive output of the electric motor 18 to the drive element 14. The drive element 14 with the aid of the mountings 30 and 31 is mounted in the housing 6 and receives the drive output-proximal ends of the motor shafts 15 and 15′. The motor shaft 15 on the side opposite the drive output side is mounted in the housing 6 with the aid of the mounting 16. The motor shaft 15′ on the side opposite the drive output side is mounted in the housing 6 with the aid of the mounting 19. This enables a comparatively easier assembly of the drive 1.

LIST OF REFERENCE SIGNS

[0054] 1 Drive [0055] 2 Steerable wheel [0056] 3 Steerable wheel [0057] 4 Axis [0058] 5 Axis [0059] 6 Housing [0060] 7 Spindle nut, drive output element [0061] 8 Axle arch [0062] 9 Axle journal [0063] 10 Axle journal [0064] 11 Steering arm [0065] 12 Steering arm [0066] 13 Tie rod, spindle [0067] 14 Drive element, coupling, drive wheel [0068] 15, 15′ Motor shaft [0069] 16 Mounting [0070] 17 Electric motor [0071] 17′ Rotor [0072] 18 Electric motor [0073] 18′ Rotor [0074] 19 Mounting [0075] 20 Timing belt [0076] 21 Gear stage, traction mechanism, spur wheel stage [0077] 22 Axis [0078] 23 Central axis [0079] 24 Mounting [0080] 25 Mounting [0081] 26 Steering axle [0082] 27 Arrow, travel direction [0083] 28 Mounting [0084] 29 Mounting [0085] 30 Mounting [0086] 31 Mounting