CN108163709B

CN108163709B - Driving axle of crane and crane

Info

Publication number: CN108163709B
Application number: CN201810236530.4A
Authority: CN
Inventors: 裴宝仁; 钟明; 朱陈嘉
Original assignee: Shanghai Zhenghua Heavy Industries Co Ltd
Current assignee: Shanghai Zhenghua Heavy Industries Co Ltd
Priority date: 2018-03-21
Filing date: 2018-03-21
Publication date: 2024-03-19
Anticipated expiration: 2038-03-21
Also published as: CN108163709A

Abstract

The invention relates to a drive axle of a crane and the crane, wherein the drive axle comprises: a motor; the differential mechanism is connected with the motor; a first drive mechanism and a second drive mechanism, the differential being located axially between the first drive mechanism and the second drive mechanism; the motor can transmit torque to the first driving mechanism and the second driving mechanism respectively through the differential mechanism, and the driving axle is arranged on the same side of the crane. The invention provides a novel driving axle, which has a compact structure, and each driving axle is provided with a differential mechanism, so that the crane can steer more flexibly.

Description

Driving axle of crane and crane

Technical Field

The invention relates to the technical field of cranes, in particular to a drive axle of a crane and the crane.

Background

The transaxle is very extensive in tire formula jack-up conveyer and engineering machine tool on, and AGV (Automated Guided Vehicle ) is a novel container transport vechicle that automatic wharf is very important, and conventional AGV is four-wheel, and its drive form is: motor + universal joint + transaxle + stopper etc.. However, the structure is heavy, the occupied space is very large, the whole machine is heavy, the steering is inflexible, and the modularized design and processing are not facilitated. Especially when developing eight-wheel AGVs, eight-wheel AGVs are because of the wheel quantity increases, and the space is limited, and four-wheel AGVs's drive form is because of occupation space is very big, is not applicable to eight-wheel AGVs.

Therefore, for space-constrained cranes, the above-described drive forms are not applicable, and development of new drive structures is highly desirable.

Disclosure of Invention

The invention solves the technical problem of providing a novel driving mechanism.

In order to solve the above problems, an object of the present invention is to provide a drive axle of a crane, comprising: a motor; the differential mechanism is connected with the motor; a first drive mechanism and a second drive mechanism, the differential being located axially between the first drive mechanism and the second drive mechanism; the motor can transmit torque to the first driving mechanism and the second driving mechanism respectively through the differential mechanism, and the driving axle is arranged on the same side of the crane.

Optionally, the method further comprises: the drive axle input shaft extends along the radial direction, the radial direction is perpendicular to the axial direction, along the radial direction, one end of the drive axle input shaft is connected with the output shaft of the motor, and the other end of the drive axle input shaft is connected with the differential mechanism through a bevel gear.

Optionally, the drive axle input shaft is in key connection with the output shaft of the motor, and along the radial direction, the drive axle input shaft is inserted into the output shaft of the motor, or the output shaft of the motor is inserted into the drive axle input shaft.

Optionally, the differential comprises a differential housing, wherein the differential housing is provided with a small bevel gear, and the other end of the driving axle input shaft is connected with the small bevel gear through a large bevel gear; the torque of the motor can be transferred to the bevel pinion via the bevel pinion such that the differential transfers torque to the first and second drive mechanisms, respectively.

Optionally, the drive axle further comprises an axle housing, at least one brake is arranged on the axle housing, the brake is provided with a friction pair, the friction pair can realize braking of the differential mechanism in an engaged state, and the brake of the differential mechanism is released in a separated state.

Optionally, the axle housing is provided with a housing portion, and the housing portion has a first portion and a second portion disposed opposite to each other along the axial direction, the first portion being closer to the differential than the second portion, and the brake is disposed in the housing portion and is connected to the first portion and the second portion, respectively.

Optionally, the device further comprises a bolt, wherein the bolt sequentially passes through the second part, the brake and the first part, and the brake is connected with the accommodating part through the bolt.

Optionally, the brake is a wet multi-disc brake.

Optionally, the wet multi-disc brake includes: a disc having an interior cavity, the differential housing being at least partially located in the interior cavity;

the piston is arranged in the inner cavity, the friction pair is arranged in the inner cavity, the piston can move along a first direction to enable the friction pair to be jointed to realize braking of the differential mechanism shell, and move along a second direction opposite to the first direction to enable the friction pair to be separated to release the braking of the differential mechanism shell, and the first direction is parallel to the axial direction.

Optionally, the friction pair includes: the first friction plate is connected with the differential mechanism shell, the second friction plate is arranged facing the piston, and the second friction plate is connected with the cavity wall of the inner cavity;

the piston can move along the second direction under the action of hydraulic pressure, and moves along the first direction after pressure relief.

Optionally, along the axial direction, the first friction plate corresponds to the second friction plate one by one, and is a plurality of and interval arrangement in proper order.

Optionally, the method further comprises: and the reset spring is connected with the piston and used for driving the piston to move along the first direction after pressure relief.

Optionally, the piston has a cavity, and the return spring is disposed in the cavity of the piston.

Optionally, the first driving mechanism and the second driving mechanism have the same structure and are all planetary gear side reducers.

Optionally, the planetary gear side reducer includes: the axle shaft is provided with a sun gear at one end and connected with the differential mechanism through a bevel gear at the other end along the axial direction;

a planetary gear meshed with the sun gear;

the planet shaft is arranged in parallel with the half shaft, the planet gear is sleeved on the planet shaft, the planet shaft is connected with the planet carrier, the planet carrier is rotatably sleeved at one end of the half shaft and is connected with the transmission hub along the radial direction, and the radial direction is perpendicular to the axial direction;

the inner gear ring is arranged with the planet carrier at intervals along the axial direction, meshed with the planet gears, and positioned between the inner gear ring and the sun gear along the radial direction;

the inner gear ring is fixedly connected with the axle housing through a connecting component.

Optionally, the method further comprises: and the speed measuring unit is used for detecting the rotating speed of the transmission hub.

Optionally, the speed measuring unit is disposed on the second portion and is connected with the second portion through the bolt.

Optionally, the speed measuring unit includes: a coding unit;

the rotating shaft is connected with the coding unit and parallel to the half shaft, and a first gear is arranged on the rotating shaft;

and the second gear is arranged on the transmission hub and meshed with the first gear.

Optionally, the sun gear and the half shaft are integrally formed.

Optionally, the tire mounting device further comprises a hub, wherein the hub is arranged on the transmission hub, and the hub is used for mounting the tire.

The invention also provides a crane comprising the drive axle of any one of the above, wherein the drive axles are positioned on the same side of the crane.

Optionally, the crane is an eight-wheel AGV trolley, and the AGV trolley is provided with any one of the drive axles at intervals along the length direction on the same side surface.

Optionally, the crane is a straddle carrier.

Alternatively, the weight of the crane is transferred via the suspension shaft to the axle housing of the drive axle and to the first and second tires mounted on the first and second drive mechanisms, respectively.

As described above, the present invention provides a novel drive axle of a crane, including: the motor and the differential mechanism connected with the motor are axially provided with a first driving mechanism and a second driving mechanism at two sides of the differential mechanism, namely the differential mechanism is positioned between the first driving mechanism and the second driving mechanism; wherein the electric machine is capable of transmitting torque to the first and second drive mechanisms via the differential, respectively. The first driving mechanism and the second driving mechanism are used for respectively installing tires, the driving axle of the invention is positioned on the same side of the crane, the differential mechanism between the first driving mechanism and the second driving mechanism can bear the weight of the crane, the structure is compact, and the space between the first driving mechanism and the second driving mechanism is reduced. Meanwhile, each driving axle is provided with a differential mechanism, so that the crane is more flexible in steering.

In order that the above-recited features of the present invention can be understood in detail, a preferred embodiment of the invention is illustrated in the accompanying drawings.

Drawings

FIG. 1 is a side view of an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a drive axle according to an embodiment of the present invention;

FIG. 3 is an enlarged view of a portion of a drive axle according to an embodiment of the present invention;

FIG. 4 is a partial enlarged view of a drive axle according to an embodiment of the present invention;

fig. 5 is a top view of the crane of the present invention.

Detailed Description

Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, by describing the embodiments of the present invention with specific examples. While the description of the invention will be described in connection with the preferred embodiments, it is not intended to limit the inventive features to the implementation. Rather, the purpose of the invention described in connection with the embodiments is to cover other alternatives or modifications, which may be extended by the claims based on the invention. The following description contains many specific details for the purpose of providing a thorough understanding of the present invention. The invention may be practiced without these specific details. Furthermore, some specific details are omitted from the description in order to avoid obscuring the invention.

Referring to fig. 1 and 2, the present invention provides a drive axle 1 of a crane, comprising: an electric motor 30, and a differential 40 coupled to the electric motor 30. In the axial direction (shown in the X direction in fig. 2), the first drive mechanism 10 and the second drive mechanism 20 are provided on both sides of the differential mechanism 40, that is, the differential mechanism 40 is located between the first drive mechanism 10 and the second drive mechanism 20; wherein the electric motor 30 is capable of transmitting torque to the first and second drive mechanisms 10 and 20, respectively, via the differential 40. The first driving mechanism 10 and the second driving mechanism 20 are used for installing the first tire 90 and the second tire 91 respectively, the driving axle 1 of the invention is located on the same side of the crane 2 (as shown in fig. 5), the differential mechanism 40 between the first driving mechanism 10 and the second driving mechanism 20 bears the weight of the crane, the structure is compact, and the space between the first driving mechanism 10 and the second driving mechanism 20 is reduced. At the same time, each drive axle 1 is provided with a differential 40, which makes the steering of the crane more flexible.

With continued reference to fig. 2, the drive axle 1 of the present invention further includes a drive axle input shaft 70, the drive axle input shaft 70 extending in a radial direction (shown in the Y-direction in fig. 2), the radial direction of the present invention being perpendicular to the axial direction. In the radial direction, the transaxle input shaft 70 is connected at one end to the output shaft 31 of the motor 30 and at the other end to the differential gear 40 via a bevel gear. Specifically, the drive axle input shaft 70 is keyed to the output shaft 31 of the motor 30, and the drive axle input shaft 70 is inserted into the output shaft 31 of the motor 30 in the radial direction; in other embodiments, the output shaft of the motor is inserted into the drive axle input shaft. Equivalently, the drive axle input shaft 70 and the output shaft 31 of the motor 30 adopt direct connection, so that the structure is compact, and the space is saved. Meanwhile, the drive axle 1 of the present invention employs the bevel gear, the differential gear 40, the first drive mechanism 10 and the second drive mechanism 20 to transmit, and converts the high rotation speed of the motor 30 into the low rotation speed of the tires provided on the first drive mechanism 10 and the second drive mechanism 20, and simultaneously transmits torque.

Referring to fig. 2, the differential 40 of the present invention includes a differential case 41, the differential case 41 being provided with a bevel pinion 42, the other end of a transaxle input shaft 70 being connected to the bevel pinion 42 through a bevel large gear 71; the torque of the motor 30 can be transmitted to the small bevel gear 42 via the large bevel gear 71 so that the differential 40 transmits the torque to the first drive mechanism 10 and the second drive mechanism 20, respectively. Equivalently, the motor 30 of the present invention works, the output shaft 31 of the motor 30 is driven by the motor 30 to rotate, the output shaft 31 of the motor 30 drives the driving axle input shaft 70 to rotate, then the driving axle input shaft 70 transmits power to the differential housing 41 through the large bevel gear 71, the differential housing 41 drives the internal gear elements, and then the first driving mechanism 10 and the second driving mechanism 20 are driven respectively.

Referring to fig. 2 and 3 in combination with fig. 1, the driving axle 1 of the present invention further includes an axle housing 11, at least one brake 50 is provided on the axle housing 11, and two brakes 50 are provided in this embodiment, and are disposed at intervals along the axial direction, and are respectively adjacent to the first driving mechanism 10 and the second driving mechanism 20. In other embodiments, other numbers of brakes may be provided. Wherein the brake 50 has a friction pair capable of realizing braking of the differential gear 40 in an engaged state, and the differential gear 40 does not transmit power to the first drive mechanism 10 and the second drive mechanism 20; the friction pair releases the braking of the differential gear 40 in a separated state, and the motor 30 can transmit torque to the first drive mechanism 10 and the second drive mechanism 20 via the differential gear 40, respectively.

Referring to fig. 2 and 3, the axle housing 11 is provided with a receiving portion having a first portion 11a and a second portion 11b disposed opposite to each other in the axial direction, the first portion 11a being located closer to the differential 40 than the second portion 11b, and the brake 50 is provided in the receiving portion and connected to the first portion 11a and the second portion 11b, respectively. The brake 50 is located in the receiving portion of the axle housing 11, which can make the structure more compact. The brake 50 is connected to the accommodating portion by a bolt 56, specifically, the bolt 56 passes through the second portion 11b, the brake 50 and the first portion 11a in sequence, and then the brake 50 is fixedly connected to the accommodating portion by a nut. In addition, the brake 50 and the accommodating part are fixedly connected through the bolt 56, the bolt 56 is convenient to detach, and the brake 50 can be replaced by a new brake 50 after the brake 50 is damaged.

With continued reference to fig. 3, the brake 50 of the present invention is a wet multi-disc brake, and in other embodiments, may be other types of brakes, so long as braking of the differential 40 is enabled. Wherein, wet multi-disc brake includes: the tray 51, the tray 51 is connected to the first portion 11a and the second portion 11b of the housing portion by bolts 56, respectively. The disc 51 of the brake 50 has an inner cavity, and the differential housing 41 is at least partially located in the inner cavity of the disc 51, resulting in a compact structure.

In addition, a piston 52 and the friction pair are provided in the inner cavity of the disc 51. Referring to fig. 3, the piston 52 is movable in a first direction (shown in direction B of fig. 3) to engage the friction pair to effect braking of the differential housing 41, which in turn effects braking of the differential 40; the piston 52 is movable in a second direction (shown in a direction a in fig. 3) opposite to the first direction parallel to the axial direction to release the friction pair from braking of the differential case 41.

Specifically, the friction pair of the present invention comprises: a first friction plate 55 and a second friction plate 54, the first friction plate 55 is connected with the differential case 41, the second friction plate 54 is disposed facing the piston 52, and the second friction plate 54 is connected with the wall of the inner cavity. The piston 52 can move along the second direction under the action of hydraulic pressure to drive the first friction plate 55 and the second friction plate 54 to be separated; the piston 52 moves in a first direction after pressure relief, and the first friction plate 55 and the second friction plate 54 are engaged.

In this embodiment, referring to fig. 3, the first friction plates 55 and the second friction plates 54 are in one-to-one correspondence along the axial direction, and are plural and sequentially arranged at intervals. In fig. 3, five first friction plates 55 and five second friction plates 54 are shown, and the sequential arrangement of the first friction plates 55 and the second friction plates 54 at intervals can be understood as follows: the first friction plates 55 and the second friction plates 54 are alternately arranged. In other embodiments, other numbers of first and second friction plates may be designed.

The first friction plate 55 of the present invention is connected to the transition spline 41a outside the differential case 41 by a key, and the second friction plate 54 is connected to the wall of the inner cavity of the disc 51, so that the first friction plate 55 and the second friction plate 54 can be replaced easily. At the same time, when the piston 52 moves in the first direction, the second friction plate 54 is able to move in the first direction axially opposite the cavity wall of the inner cavity, so that the second friction plate 54 will engage the first friction plate 55, effecting braking of the differential housing 41. When the piston 52 moves along the second direction, the differential housing 41 continues to rotate, the second friction plate 54 is "thrown away" at a moment when the differential housing 41 rotates, the second friction plate 54 moves back along the second direction, and the friction pair is convenient to use.

With continued reference to fig. 3, the brake 50 of the present invention further includes: and a return spring 53, the return spring 53 being connected to the piston 52 for driving the piston 52 to move in the first direction after the pressure relief. After the hydraulic oil is filled into the inner cavity of the disc body 51 through the liquid inlet 57, the piston 52 can move along the second direction under the hydraulic action of the hydraulic oil, and the return spring 53 elastically deforms to generate elastic force; the hydraulic oil in the inner cavity is discharged through the liquid inlet 57, and after the inner cavity of the disc body 51 is depressurized, the piston 52 moves in the first direction under the elastic force of the return spring 53.

Referring to fig. 3, in the present embodiment, the piston 52 has a cavity, and the return spring 53 is provided in the cavity of the piston 52. In other embodiments, the return spring may be provided on the outside of the piston, so long as it is capable of driving the piston to move in the first direction after pressure relief. The inner cavity of the piston 52 serves to accommodate the return spring 53 on the one hand, and the return spring 53 is provided in the cavity of the piston 52 to serve as an axial guide, so that the piston 52 can smoothly move in the first direction or the second direction.

The first driving mechanism 10 and the second driving mechanism 20 of the present invention have the same structure and are planetary gear reducers. Referring to fig. 4 in combination with fig. 2, the planetary gear side reducer includes: the half shaft 12, along the axial direction, one end of the half shaft 12 is provided with a sun gear 14, and the other end is connected with the differential mechanism 40 through a bevel gear; a planetary gear 13 meshed with the sun gear 14; the planetary shaft 15 is arranged in parallel with the half shaft 12, the planetary gear 13 is sleeved on the planetary shaft 15, the planetary shaft 15 is connected with the planetary carrier 16, the planetary carrier 16 is rotatably sleeved at one end of the half shaft 12 and is connected with the transmission hub 80 along the radial direction, and the radial direction is perpendicular to the axial direction; an inner gear ring 17 axially spaced from the planet carrier 16, meshed with the planet gears 13, and radially positioned between the inner gear ring 17 and the sun gear 14; the ring gear 17 is fixedly connected with the axle housing 11 through a connection member.

It should be noted that the number of the planetary gears 13 of the present invention is not limited, and two planetary gears 13 are shown in fig. 4; in other embodiments, a corresponding number of planet gears may be selected according to actual needs. In addition, the sun gear 14 and the half shaft 12 are integrally formed, and the half shaft 12 drives the planetary gear 13 more stably. In other embodiments, the sun gear and half shaft may be machined separately and assembled together.

So designed, differential 40 drives axle shaft 12 to rotate and sun gear 14 rotates synchronously; then, the sun gear 14 drives the planetary gear 13 to rotate, and during the rotation of the planetary gear 13, the planet carrier 16 rotates along with the planetary gear, so that the transmission hub 80 is driven to rotate, the tire mounted on the transmission hub 80 rotates, and finally the crane walks. In this embodiment, the planetary gear 13 and the sun gear 14 are hard tooth face gears, so that the bearing capacity of the driving mechanism can be improved.

With continued reference to fig. 2 and 3, the transaxle 1 of the present invention further includes: the speed measuring unit 60 is used for detecting the rotating speed of the transmission hub 80. The speed measuring unit 60 is provided at the second portion 11b of the axle housing 11 and is connected to the second portion 11b of the axle housing 11 by the bolts 56 fixing the brake 50. That is, the speed measuring unit 60 and the brake 50 share one bolt 56, which saves cost, and simultaneously, makes the structure compact and saves space.

In this embodiment, the speed measuring unit 60 includes: the encoding unit 61 and the pivot 62 that connects with the encoding unit 61, the pivot 62 is parallel to the half shaft 12, and there is a first gear 63 on the pivot 62, and the first gear 63 meshes with a second gear 81 provided on the transmission hub 80. The first gear 63 and the second gear 81 are designed with a certain speed ratio so that the rotational speed of the transmission hub 80 and thus the rotational speed of the tire can be measured by the encoding unit 61.

Referring to fig. 1 and 2, the drive axle 1 of the present invention further comprises a hub (not shown) provided to the drive hub 80 for mounting the tire.

In summary, the novel driving axle 1 provided by the invention is integrated with the motor 30, the first driving mechanism 10, the second driving mechanism 20, the differential mechanism 40, the brake 50 and the speed measuring unit 60, and has compact structure and small occupied space.

Referring to fig. 5, and in combination with fig. 1 to 4, the present invention further provides a crane 2, including the drive axle 1 of any of the above embodiments, where the drive axle 1 is located on the same side of the crane 2. In this embodiment, the crane 2 is an eight-wheel AGV trolley, and the two drive axles 1 according to any of the above embodiments are provided at intervals in the longitudinal direction (C direction in fig. 5) on the same side surface of the AGV trolley. The weight of the crane 2 is transmitted to the axle housing 11 of the transaxle 1 via a suspension shaft (not shown), and to the first tire 90 and the second tire 91 respectively mounted on the first driving mechanism 10 and the second driving mechanism 20. Since each drive axle 1 is provided with a differential 40, the steering of the crane 2 is made more flexible.

In other embodiments, the crane is a straddle carrier, or other space constrained crane, such as a sixteen-wheel crane.

In summary, the above embodiments are provided to illustrate the principles of the present invention and its efficacy, but not to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A drive axle for a crane, comprising:

a motor;

the differential mechanism is connected with the motor;

a first driving mechanism and a second driving mechanism for respectively mounting tires; axially, the differential is located between the first and second drive mechanisms;

the motor can transmit torque to the first driving mechanism and the second driving mechanism through the differential mechanism respectively, so that the high rotating speed of the motor is converted into the low rotating speed of tires arranged on the first driving mechanism and the second driving mechanism; the driving axle is arranged on the same side of the crane in the length direction;

further comprises: the drive axle input shaft extends along the radial direction, the radial direction is perpendicular to the axial direction, one end of the drive axle input shaft is connected with the output shaft of the motor, and the other end of the drive axle input shaft is connected with the differential mechanism through a bevel gear;

the drive axle input shaft is connected with the output shaft of the motor in a key way, and the drive axle input shaft is inserted into the output shaft of the motor along the radial direction, or the output shaft of the motor is inserted into the drive axle input shaft;

the differential mechanism comprises a differential mechanism shell, wherein the differential mechanism shell is provided with a small bevel gear, and the other end of the driving axle input shaft is connected with the small bevel gear through a large bevel gear; the torque of the motor can be transferred to the bevel pinion via the bevel pinion such that the differential transfers torque to the first and second drive mechanisms, respectively.

2. The drive axle of claim 1, further comprising an axle housing having at least one brake thereon, the brake having a friction pair capable of effecting braking of the differential in an engaged condition and releasing braking of the differential in a disengaged condition.

3. The transaxle of claim 2 wherein the axle housing is provided with a receiving portion having oppositely disposed first and second portions along the axial direction, the first portion being closer to the differential than the second portion, the brake being provided in the receiving portion and being connected to the first and second portions, respectively.

4. The drive axle of claim 3 further comprising a bolt passing through the second portion, the brake and the first portion in sequence, the brake being connected to the receptacle by the bolt.

5. The transaxle of claim 2 wherein the brake is a wet multi-disc brake.

6. The transaxle of claim 5 wherein the wet multi-disc brake comprises:

a disc having an interior cavity, the differential housing being at least partially located in the interior cavity;

7. The drive axle of claim 6 wherein the drive axle,

the friction pair comprises: the first friction plate is connected with the differential mechanism shell, the second friction plate is arranged facing the piston, and the second friction plate is connected with the cavity wall of the inner cavity;

8. The axle of claim 7 wherein said first friction plate and said second friction plate are in one-to-one correspondence along said axial direction and are plural and spaced apart in sequence.

9. The transaxle of claim 7 further comprising: and the reset spring is connected with the piston and used for driving the piston to move along the first direction after pressure relief.

10. The drive axle of claim 9 wherein said piston has a cavity and said return spring is disposed within said piston cavity.

11. The drive axle of claim 4 wherein said first drive mechanism and said second drive mechanism are identical in construction and are each a planetary gear reducer.

12. The drive axle of claim 11 wherein the planetary gear side reducer comprises:

the axle shaft is provided with a sun gear at one end and connected with the differential mechanism through a bevel gear at the other end along the axial direction;

a planetary gear meshed with the sun gear;

the planet shaft is arranged in parallel with the half shaft, the planet gear is sleeved on the planet shaft, the planet shaft is connected with the planet carrier, and the planet carrier is rotatably sleeved at one end of the half shaft and is connected with the transmission hub along the radial direction;

13. The transaxle of claim 12 further comprising: and the speed measuring unit is used for detecting the rotating speed of the transmission hub.

14. The drive axle of claim 13 wherein said tachometer unit is disposed in said second portion and is connected to said second portion by said bolt.

15. The drive axle of claim 13 wherein said speed measurement unit comprises:

a coding unit;

16. The drive axle of claim 12 wherein said sun gear and said axle shaft are integrally formed.

17. The drive axle of claim 12 further comprising a hub disposed on said drive hub, said hub for mounting a tire.

18. A crane comprising a drive axle according to any one of claims 1-17, said drive axles being located on the same side of the crane.

19. The crane of claim 18 wherein said crane is an eight-wheel AGV trolley, said AGV trolleys being longitudinally spaced apart on the same side by said drive axles.

20. The crane of claim 18, wherein the crane is a straddle carrier.

21. The crane of claim 18, wherein the weight of the crane is transferred via the suspension shaft to the axle housing of the drive axle and to the first and second tires mounted to the first and second drive mechanisms, respectively.