Steering shaft for land transport vehicle

Abstract

The invention relates to a steering shaft for a land transport vehicle, comprising an axle 1, a first shaft housing 2 being arranged in both end regions of the axle so as to be pivotable about a first vertical steering shaft 3 and a second shaft housing 4 being arranged so as to be pivotable about a second vertical steering shaft 5, the first shaft housing and the second shaft housing each carrying a wheel 6, 7. The steering shaft also has an electric motor 10 arranged in the middle of the axle 1, and the shaft housing 2, 4 can be pivotally driven by an output shaft 11 of the electric motor directly or indirectly via transmission means. A radial lever assembly can be pivotally driven by the output shaft 11, which radial lever assembly has one or two lever elements 13, 14 that extend radially horizontally with respect to the output shaft 11, on which lever elements a first track rod 15 and a second track rod 16 are hinged with one end thereof or each, the first track rod 15 being guided to a first shaft housing lever 17, the second track rod 16 being guided to a second shaft housing lever 17, and the second track rod 16 being guided to a second shaft housing lever 17. The first steering axle 3 is guided to a first axle housing rod 18, which extends horizontally and is fixedly connected to the first axle housing 2, and a first tie rod 15 is hinged to the first axle housing rod at a radial distance from the first steering axle 3, and wherein the second tie rod 16 is guided to a second axle housing rod 18, which extends horizontally and is fixedly connected to the second axle housing 4, the second steering track rod 16 is hinged to the second shaft housing rod at a radial distance from the second steering shaft 5.

Description

Technical Field

[0001] The present invention relates to a steering axle for a land transport vehicle, the steering axle comprising: an axle, a first axle housing being pivotable about a first vertical steering axle and a second axle housing being pivotable about a second vertical steering axle in the two end regions of the axle, the first axle housing and the second axle housing respectively carrying wheels; and an electric motor being arranged in the middle of the axle, the axle housing being pivotably driven by an output shaft of the electric motor directly or indirectly via a transmission device. Background Art

[0002] In such steering axles for land transport vehicles, it is known that the transmission device has a coupling spur gear which is rotatably driven by an electric motor, and two connecting shafts which are parallel to the output shaft of the electric motor can be rotatably driven by the coupling spur gear, wherein the connecting shafts each drive a belt of a belt drive which runs around a pulley connected to the respective axle housing. When the output shaft is driven by the electric motor, the pivoting drive of the axle housing is realized by the belt drive.

[0003] This construction is complex and has a large number of components which require a large amount of installation space and have to be coordinated with one another in a complex manner. Summary of the invention

[0004] The object of the present invention is to provide a steering axle for a land transport vehicle of the type mentioned above which avoids these disadvantages and has a compact and inexpensive construction with a small number of simple components.

[0005] According to the invention, this object is achieved in that a radial rod assembly can be pivotally driven by an output shaft, the radial rod assembly having one or two rod elements extending radially horizontally relative to the output shaft, a first steering tie rod and a second steering tie rod being hinged or respectively hinged to the rod element with one end thereof, wherein the first steering tie rod leads to a first shaft housing rod, the first shaft housing rod extending horizontally is fixedly connected to the first shaft housing, and the first steering tie rod is hinged to the first shaft housing rod at a radial distance from the first steering shaft, and wherein the second steering tie rod leads to a second shaft housing rod, the second shaft housing rod extending horizontally is fixedly connected to the second shaft housing, and the second steering tie rod is hinged to the second shaft housing rod at a radial distance from the second steering shaft.

[0006] In this case, the axle is preferably a cast component.

[0007] This construction has only a few simple components, is easy to install and requires little installation space.

[0008] If the planetary transmission arranged on the axle can be driven by the output shaft of the electric motor, and the radial rod assembly can be pivotally driven by the driven shaft of the planetary transmission, wherein the rotational speed of the output shaft of the electric motor can be driven in a reduced manner by the planetary transmission, then due to the smaller rotational speed of the output shaft relative to the driven shaft of the planetary transmission, the torque on the driven shaft is greater than the torque of the electric motor.

[0009] To protect against contamination and mechanical damage, the electric motor and / or the planetary gear can be arranged in a housing that is fixedly connected to the axle.

[0010] A further reduction in components can be achieved by forming the axle and the housing of the electric motor and / or the planetary gear in one piece, so that the axle performs a dual function.

[0011] If the axle and the housing are designed as cast components, this design is easy to produce.

[0012] If the ring gear of the planetary gear is fixedly arranged in a housing bore formed in the axle, the required installation space and the number of components are further reduced.

[0013] In this case, the ring gear can be fixedly arranged, for example, by being pressed into a housing bore.

[0014] A reduction in components also results if the first axle housing rod is designed in one piece with the first axle housing and the second axle housing rod is designed in one piece with the second axle housing.

[0015] If the lever element extends at least approximately in the opposite direction to the axle housing rod when the land transport vehicle is traveling straight ahead, a bending lever effect occurs, especially at the maximum wheel steering angles. This results in an increase in the tensile and compressive forces in the tie rod, which counteracts the increased torque losses at the wheel due to the reduction in the effective length of the axle housing rod. Thus, at the maximum wheel steering angles, a greater steering torque is provided at the wheel due to the bending lever effect.

[0016] The freedom of movement of the steering spindle according to the invention can also be used to reduce steering angle errors and for larger steering angles.

[0017] The rod element extending radially horizontally relative to the output shaft can be a single component to which the first tie rod and the second tie rod are articulated with one end thereof, which leads to a further reduction in the number of components. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments of the present invention are shown in the drawings and described in detail below.

[0019] Figure 1 The schematic diagram shows the steering axis in a side view in the straight-ahead position,

[0020] Figure 2 Shown according to Figure 1 Schematic diagram of the top view of the steering axis in the straight-ahead position,

[0021] Figure 3 Shown according to Figure 1 A perspective view of the steering shaft. DETAILED DESCRIPTION

[0022] The steering axle for a land transport vehicle, in particular a forklift, shown in the drawings has an axle 1 which is fixedly arranged on a frame (not shown) of the land transport vehicle. The steering axle is here the rear axle of the land transport vehicle.

[0023] The first axle housing 2 is arranged at an end region of the axle 1 so as to be pivotable about a first vertical steering axis 3 .

[0024] The second axle housing 4 is arranged at a second end region of the axle 1 so as to be pivotable about a second vertical steering axis 5 .

[0025] Each axle housing 2 , 4 carries a wheel 6 , 7 .

[0026] In the center of the axle 1 , which is designed as a cast component, a housing bore 8 is formed vertically in the axle 1 , in which a planetary gear 9 is arranged.

[0027] The planetary gear 9 can be driven about a vertical output shaft 11 by a reversible electric motor 10 which is fastened concentrically to the planetary gear 8 on the axle 1 .

[0028] Two rod elements 13 , 14 projecting radially from the output shaft are arranged as one-piece components on a vertical output shaft 12 of the planetary gear 9 coaxial to the output shaft 11 and can be pivotally driven by the planetary gear 9 .

[0029] One end of the first tie rod 15 is articulated at the free end of the first rod element 13 , and one end of the second tie rod 16 is articulated at the free end of the second rod element 14 .

[0030] The second end of the first tie rod 15 is articulated at a radial distance from the first steering shaft 3 at the free end of a first axle housing rod 17 which is formed in one piece with the first axle housing 2 and extends radially relative to the first steering shaft 3 .

[0031] The second end of the second tie rod 16 is articulated at a radial distance from the second steering shaft 5 at the free end of a second axle housing rod 18 which is formed in one piece with the second axle housing 4 and extends radially relative to the second steering shaft 5 .

[0032] In the illustrated straight-ahead travel of the land transport vehicle, the rod elements 13 , 14 extend at least approximately in a direction opposite to the axle housing rods 17 , 18 .

[0033] Reference numerals list

[0034] 1 Axle

[0035] 2First shaft housing

[0036] 3First steering axis

[0037] 4 Second shaft housing

[0038] 5 Second steering axis

[0039] 6 wheels

[0040] 7 wheels

[0041] 8 Shell holes

[0042] 9Planetary Transmission

[0043] 10 Electric Motor

[0044] 11 Output shaft

[0045] 12 Driven shaft

[0046] 13 First rod element

[0047] 14 Second rod element

[0048] 15First steering tie rod

[0049] 16 Second steering tie rod

[0050] 17 First shaft housing rod

[0051] 18 Second shaft housing rod

Claims

1. Steering axle for a land vehicle, said steering axle having: an axle (1), a first axle housing (2) pivotally arranged about a first vertical steering axis (3) and a second axle housing (4) pivotally arranged about a second vertical steering axis (5) in two end regions of said axle, the first and second axle housings each carrying a wheel (6, 7); an electric motor (10) arranged in the middle of said axle (1), and said axle housings (2, 4) being pivotally drivable directly or indirectly via a transmission device by an output shaft (11) of said electric motor, characterized in that, a radial rod assembly is pivotally drivable by said output shaft (11), said radial rod assembly having one or two rod elements (13, 14) extending radially horizontally relative to the output shaft (11), a first steering tie rod (15) and a second steering tie rod (16) being hinged or respectively hinged at one of their ends to said rod elements, wherein said first steering tie rod (15) is guided to a first axle housing rod (17), said first axle housing rod being fixedly connected to said first axle housing (2) extending horizontally, and said first steering tie rod (15) being hinged to said first axle housing rod radially spaced apart from said first steering axis (3), and wherein said second steering tie rod (16) is guided to a second axle housing rod (18), said second axle housing rod being fixedly connected to said second axle housing (4) extending horizontally, and said second steering tie rod (16) being hinged to said second axle housing rod radially spaced apart from said second steering axis (5).

2. The steering axle according to claim 1, characterized in that, a planetary gear set (9) arranged on said axle (1) is drivable by an output shaft (11) of an electric motor (10), and said radial rod assembly is pivotally drivable by a driven shaft (12) of the planetary gear set, wherein the rotational speed of the output shaft (11) of said electric motor (10) is decelerated and driven by said planetary gear set (9).

3. The steering axle according to any one of the preceding claims, characterized in that, said electric motor and / or said planetary gear set (9) is arranged in a housing fixedly connected to said axle (1).

4. The steering axle according to claim 3, characterized in that, said axle (1) is constructed in one piece with the housing of said electric motor and / or said planetary gear set (9).

5. The steering axle according to claim 4, characterized in that, the ring gear of said planetary gear set (9) is fixedly arranged in a housing bore (8) constructed in said axle (1).

6. The steering axle according to any one of the preceding claims, characterized in that, said first axle housing rod (17) is constructed in one piece with said first axle housing (2), and said second axle housing rod (18) is constructed in one piece with said second axle housing (4).

7. The steering axle according to any one of the preceding claims, characterized in that, When the land vehicle is traveling straight, the rod elements (13, 14) extend at least approximately in a direction opposite to that of the shaft housing rods (17, 18).

8. The steering shaft according to any one of the preceding claims, characterized in that the rod elements (14, 15) extending horizontally radially with respect to the output shaft (11) are a single piece, and the first steering tie rod (15) and the second steering tie rod (16) are articulated at their ends to the piece.

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