CN111320087A

CN111320087A - Straddle carrier

Info

Publication number: CN111320087A
Application number: CN202010268388.9A
Authority: CN
Inventors: 薛海雷
Original assignee: Shanghai Zhenghua Heavy Industries Co Ltd
Current assignee: Shanghai Gangji Heavy Industry Co Ltd
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2020-06-23
Anticipated expiration: 2040-04-08
Also published as: CN111320087B

Abstract

The invention discloses a straddle carrier, which comprises a plurality of wheel assemblies and a lifting appliance distributed at the bottom of the straddle carrier, wherein the straddle carrier is free of an independent lifting mechanism for lifting the lifting appliance, the lifting appliance is provided with a transfer pin matched with a lock pin hole on a container, each wheel assembly comprises a suspension oil cylinder with a lifting function and a wheel frame, the suspension oil cylinder is arranged on the wheel frame, when the suspension oil cylinder is at a first lifting height, the lifting appliance is positioned at a first fixed height, the first fixed height is matched with the height of a container to be lifted, so that the transfer pin on the lifting appliance can be locked into the lock pin hole in the container, when the suspension oil cylinder is at a second lifting height, the lifting appliance is lifted to a second fixed height, and the second fixed height is higher than the first fixed height. The straddle carrier can effectively reduce the dead weight of the straddle carrier, can independently load and unload containers, does not need the assistance of other hoisting equipment, and reduces the energy consumption.

Description

Straddle carrier

Technical Field

The invention relates to the field of container transportation, in particular to a straddle carrier.

Background

A port box-crossing transport vehicle, which is called a cross transport vehicle for short, is generally used for carrying containers in ports and storage yard areas. The straddle carrier equipment is generally heavy, so that when the container is transported, the energy consumption is large, and the size of the used tire is large to meet the use working condition, so that the tire maintenance and replacement cost is high.

Patent document CN105621263A discloses a light container straddle carrier, wherein a lifting mechanism of the straddle carrier comprises four metal mechanism frames, two hanging brackets are supported above the four metal mechanism frames, the two hanging brackets are of a two-layer structure, an inner layer structure is made of a titanium alloy material with the thickness of 4mm, an outer layer structure is made of a stainless steel material with the thickness of 2mm, and the two-layer hanging brackets are designed to enhance the strength of the hanging brackets and cannot be corroded by air or rainwater; two ends of each hanger are provided with a rope winding system; the rope winding system comprises a plurality of pulleys and a plurality of steel wire ropes, and the stress direction of the steel wire ropes can be simply changed through the pulleys. And the rope winding system is also connected with the two hydraulic cylinders 1; the rope winding systems are arranged at the two ends of the two hanging brackets, so that the light container straddle carrier can be effectively prevented from deflection caused by uneven stress in the process of lifting the goods; the lifting mechanism adopts a hydraulic slide block mode, and the same generator is adopted as a power source with the cart running mechanism, so that the operation is stable. Compared with a general container straddle carrier, the straddle carrier is only provided with a hydraulic cylinder and corresponding pipelines, so that the conventional configurations of a motor, a speed reducer, a brake, a roller and the like are omitted, and the self weight and the cost of the whole straddle carrier are obviously reduced. The lifting mechanism in the document has the rated lifting capacity of 35t and the lifting height of 5m, and ensures the safety of the light container straddle carrier.

Patent document CN1785777A discloses a straddle carrier, the main structural components of which include a straddle carrier spreader, a cart running mechanism 2, a hoisting mechanism 3 and a translation mechanism. The straddle carrier lifting appliance 1 is hung on a lifting mechanism 3, can be driven by the lifting mechanism 3 to lift or descend, and is connected with a translation mechanism and can be driven by the translation mechanism to move horizontally. The span transport vehicle can hoist the foot container or the foot container, the bending moments borne by the spreader beam are equal, so that the section of the main beam is simple, the sectional area is reduced, and the weight of the whole machine is reduced. In addition, when the foot container is hoisted, the load of the hoisting box is borne by the supporting block in the hoisting assembly, and the lifting oil cylinder only bears the dead weight of the rotating pin box, so that the oil cylinder can be made smaller and light.

As can be seen from the above, the prior art optimizes the structure of the straddle carrier to minimize the weight of the straddle carrier while stabilizing the hoisting mechanism. However, the weight of the existing straddle carrier still varies from 50 t to 70t, for example, in patent document CN105621263A, the weight of only the hoisting mechanism reaches 35t, so the current straddle carrier still has the problem of large dead weight.

Disclosure of Invention

The invention provides a straddle carrier, which is used for solving the technical problem.

The embodiment of the invention discloses a straddle carrier, which comprises a plurality of wheel assemblies and a lifting appliance distributed at the bottom of the straddle carrier, wherein an independent lifting mechanism for lifting the lifting appliance is omitted from the straddle carrier, the lifting appliance is provided with a transfer pin matched with a lock pin hole on a container, each wheel assembly comprises a suspension oil cylinder with a lifting function and a wheel frame, the suspension oil cylinder is arranged on the wheel frame, when the suspension oil cylinder is at a first lifting height, the lifting appliance is positioned at a first fixed height, the first fixed height is adaptive to the height of a container to be lifted, so that the transfer pin on the lifting appliance can be locked into the lock pin hole in the container, when the suspension oil cylinder is at a second lifting height, the lifting appliance is lifted to a second fixed height, and the second fixed height is higher than the first fixed height.

By adopting the technical scheme, the self weight of the straddle carrier can be effectively reduced, the container can be loaded and unloaded independently, the assistance of other hoisting equipment is not needed, and the energy consumption is reduced.

According to another embodiment of the invention, there is disclosed a straddle carrier having a spreader at a first fixed height corresponding to the height of a pre-hoisted container on the ground.

According to another embodiment of the invention, the straddle carrier is disclosed, wherein when the spreader is locked into the lock pin hole of the container and the spreader is at the second fixed height, the gap between the bottom of the container to be lifted and the ground is 150-200 mm.

According to another specific embodiment of the invention, the embodiment of the invention discloses a straddle carrier, which further comprises a frame, wherein a lifting appliance is arranged on the frame, and the wheel frame is fixedly connected with the frame.

According to another embodiment of the invention, the straddle carrier further comprises a transverse micro-motion device fixedly connected with the spreader, wherein the transverse micro-motion device is used for driving the spreader to move in a transverse direction so as to adjust the position of the spreader in the transverse direction, and the transverse direction is perpendicular to the advancing direction of the straddle carrier.

According to another specific embodiment of the invention, the embodiment of the invention discloses a straddle carrier, wherein a transverse micro-motion device comprises a roller, a connecting frame and an execution oil cylinder, the vehicle frame is provided with a fixed cross beam extending along the transverse direction, the roller is positioned on the fixed cross beam, the execution oil cylinder is transversely connected with the roller, the connecting frame is fixedly connected with the roller and a lifting appliance, and the roller is driven to transversely roll on the fixed cross beam through the extension and contraction of the oil cylinder, so that the lifting appliance moves in the transverse direction.

According to another embodiment of the invention, there is disclosed a straddle carrier having two transverse micro-motion devices spaced longitudinally along the spreader.

According to another embodiment of the invention, the invention discloses a straddle carrier, wherein a wheel frame comprises an upper support beam and a lower support beam for connecting a rotating shaft of the upper support beam and the lower support beam, the upper support beam is fixedly connected with a vehicle frame, the upper end of a suspension cylinder is fixedly connected with the upper support beam, the lower end of the suspension cylinder is fixedly connected with the lower support beam, and the lower support beam can rotate along the rotating shaft through the extension and contraction of the suspension cylinder so as to extend or shorten the height of the wheel frame.

According to another embodiment of the invention, the wheel assembly further comprises a wheel set, and the wheel set is provided with two wheels which are symmetrically arranged along the transverse direction.

According to another embodiment of the invention, the embodiment of the invention discloses a straddle carrier, a drive axle is connected between two wheels, and the drive axle comprises a differential device and a built-in hydraulic multi-disc brake disc.

In accordance with another embodiment of the present invention, a straddle carrier is disclosed, the plurality of wheel assemblies including a drive wheel assembly and a steering wheel assembly.

In accordance with another embodiment of the present invention, a straddle carrier is disclosed that is also equipped with a cab.

Drawings

FIG. 1 shows a schematic view of a straddle carrier according to an embodiment of the invention;

FIG. 2 shows a side view of a straddle carrier according to an embodiment of the present invention;

FIG. 3 shows a close-up view at I in FIG. 2;

FIG. 4 shows a schematic view of another embodiment of the straddle carrier of the present invention;

FIG. 5 shows a schematic view of the embodiment of the present invention after the straddle carrier has been raised;

FIG. 6 shows a schematic view of a wheel assembly (both side tires hidden) according to a specific embodiment of the present invention;

FIG. 7 shows a side view of a wheel assembly according to an exemplary embodiment of the present invention;

FIG. 8 shows a schematic view of the straddle carrier steering of an embodiment of the present invention;

fig. 9 shows a schematic of the incline of the straddle carrier of an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure. While the invention will be described in conjunction with the preferred embodiments, it is not intended that features of the invention be limited to these embodiments. On the contrary, the invention is described in connection with the embodiments for the purpose of covering alternatives or modifications that may be extended based on the claims of the present invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be practiced without these particulars. Moreover, some of the specific details have been left out of the description in order to avoid obscuring or obscuring the focus of the present invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

It should be noted that in this specification, like reference numerals and letters refer to like items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The inventor of the invention finds that an independent lifting mechanism can be arranged on a common straddle carrier, the lifting mechanism is connected with a lifting appliance and is used for lifting, descending, translating and the like, and the lifting appliance is used for locking a container to realize fixed connection with the container. The lifting mechanism is matched with the lifting appliance to participate in box stacking operation, and the box stacking operation capacity is 2 or 3 boxes in height. Therefore, the hoisting mechanisms on the straddle carriers need to be assembled into a higher frame, and in order to maintain the stability of the transfer containers, the hoisting mechanisms and the connection and assembly of the hoisting mechanisms and the spreaders are more complicated, which also makes the hoisting mechanisms heavier and occupies the main weight of the straddle carriers.

To this end, as shown in fig. 1 to 9, the present invention provides a straddle carrier including a plurality of wheel assemblies distributed at the bottom of the straddle carrier for moving the straddle carrier. The straddle carrier further comprises a spreader 101, the spreader 101 being provided with transfer pins matching the locking pin holes on the containers 106, the locking pin holes on the containers being now uniformly arranged, so that the transfer pins on the spreader 101 may also be uniformly arranged. Unlike the prior art, the straddle carrier of the present invention omits a separate lifting mechanism for lifting the spreader, and instead, a suspension cylinder 204 having a lifting function is installed in the wheel assembly. The wheel assembly also includes a wheel frame on which the suspension cylinder 204 is mounted. The suspension cylinders 204 have different lift heights, and the height of the spreader 101 in the straddle carrier of the present invention can be raised and lowered as the suspension cylinders 204 are raised and lowered. When the suspension cylinder 204 is at the first jacking height, the spreader 101 is at a first fixed height which is adapted to the height of the container 106 to be hoisted, so that after the straddle carrier is driven to a proper horizontal position, when the suspension cylinder 204 is lowered to the first jacking height, the transfer pin on the spreader 101 can be embedded into the lock pin hole, and then the transfer pin can be locked into the lock pin hole by rotating the transfer pin and the like. When the suspension cylinder 204 is at the second jacking height, the spreader 101 will be correspondingly jacked to the second fixed height. Since the second fixed height is higher than the first fixed height, the spreader 101 is lifted to the second fixed height after completing the locking with the container 106 at the first fixed height, and then the container 106 can be lifted.

Therefore, the straddle carrier is not provided with an independent lifting mechanism, the weight of the straddle carrier can be greatly reduced, the suspension oil cylinder in the wheel assembly can be adjusted to play a role of lifting a lifting appliance, the self weight of the straddle carrier can be reduced while the function of straddle carrying is kept, meanwhile, the complex structure designed for ensuring the stability of the lifting mechanism can be simplified, and the straddle carrier is convenient and flexible. Because the invention has no hoisting mechanism, the dead weight of the straddle carrier can be controlled within the range of 20-30t, and the dead weight is obviously reduced compared with the prior straddle carrier.

In the above embodiment, the spreader 101 itself is fixed to the straddle carrier, and when the suspension cylinder 204 is not lifted, the spreader 101 itself has the initial height, and the height of the spreader 101 is determined by the combination of the initial height of the spreader 101 and the lifting height of the suspension cylinder 204. Because the height range of the suspension cylinder 204 is limited, the initial height of the spreader 101 itself needs to be close to the height of the container 106 to be lifted, and then the adjustment of the suspension cylinder 204 is combined, so that the height of the spreader 101 can be adapted to the height of the container 106 to be lifted. In this embodiment, the initial height of the spreader 101 may be the first fixed height of the spreader, and the suspension cylinder 204 is not lifted. Or the initial height of the spreader 101 may be slightly lower than the first fixed height, and the spreader 101 is at the first fixed height by fine adjustment of the suspension cylinders 204. Therefore, the first jacking height in the above embodiment may be a height when the suspension cylinder is in a non-jacking state, or a height when the suspension cylinder is jacked to a certain height.

The initial height of the spreader 101 of this embodiment may be at or slightly below the height of two boxes, so that the fixed handling height of the straddle carrier of this embodiment is the height of two boxes by the adjustment of the suspension cylinders 204. Since the initial height of the spreader 101 is fixed, the transfer height of the straddle carrier is also fixed, i.e. generally sufficient for the lifting of containers of one height. This embodiment is preferred when the spreader 101 is at a first fixed height, which is adapted to the height of the pre-hoisted container on the ground. That is, the initial height of the spreader 101 is set at a height corresponding to the height of the pre-hoisted container on the ground or slightly lower than the height of the pre-hoisted container. Specifically, the straddle carrier generally includes a frame 108, and the spreader 101 is fixed to the frame 108, and if the initial height of the spreader 101 is high, the frame 108 is correspondingly set high, which also increases the weight. The present embodiment sets the spreader 101 at a position as low as possible, i.e., the transfer height of the straddle carrier matches the height of the containers 106 on the ground, for transferring the containers 106 on the ground, thereby further reducing the heights of the spreader and the vehicle frame, further reducing the weight of the straddle carrier, and facilitating the transfer of the containers on the ground by the straddle carrier.

Optionally, when the spreader 101 is locked into the locking pin holes of the container and the spreader 101 is at the second fixed height, the gap between the bottom of the container 106 being lifted and the ground is 150 and 200mm, so as to lift the container 106 at the lowest possible height.

In the above embodiment, the straddle carrier further comprises a frame 108, the frame 108 is fixedly connected to the wheel frame and the spreader 101, respectively, the bottom of the frame 108 is connected to the wheel frame and extends in the height direction, and when the suspension cylinder 204 is lifted, the force is transmitted to the spreader 101 through the wheel frame and the frame 108, so that the spreader 101 is lifted.

As shown in fig. 1-3, in the above embodiments, the straddle carrier further comprises a transverse micro-motion device 3 fixedly connected to the spreader for driving the spreader 101 to move in a transverse direction for adjusting the position of the spreader in the transverse direction, i.e. in a direction perpendicular to the advancing direction of the straddle carrier, in a horizontal plane, such as the x direction in fig. 2. Specifically, frame 108 has a transversely extending fixed cross member 1081, and spreader 101 is located below fixed cross member 1081, i.e., fixed cross member 1081 spans spreader 101. There is space below the spreader 101 for accommodating a lifted container. The transverse micro-motion device 3 of the embodiment comprises a roller 31, a connecting frame 32 and an execution oil cylinder 33, wherein the roller 31 stands on the fixed cross beam 1081, and the execution oil cylinder 33 is transversely connected with the roller 31, so that the roller 31 can be driven to transversely move when the execution oil cylinder extends and retracts. The connecting frame 32 is fixedly connected with the rollers 31 and the lifting appliance 101.

Referring to fig. 2, the actuating cylinder 33 extends out to drive the roller 31 to move rightward on the fixed cross beam 1081 in the transverse direction, and drive the connecting frame 32 to move rightward, so as to drive the spreader 101 to move rightward. The actuating cylinder 33 contracts to drive the roller 31 to move leftwards on the fixed cross beam 1081, and drive the connecting frame 32 to move leftwards, so as to drive the lifting appliance 101 to move leftwards. The fixed cross beam 1081 provides a track for the movement of the roller 31, the number of the rollers 31 on the transverse micro-motion device 3 in this embodiment may be two, and the two ends of the connecting frame 32 in the transverse direction are respectively fixedly connected with the spreader 101. Through the arrangement of the transverse micro-motion device 3, the precise adjustment of the transverse position of the spreader 101 can be realized, and the alignment of the spreader 101 and the container 106 to be lifted can be realized. The adjustment of the lateral micro-motion device 3 is more convenient and accurate than the alignment of the container 106 by moving the straddle carrier.

In the above embodiment, the spreader 101 extends in the longitudinal direction of the straddle carrier, for example, the y direction in fig. 1, coinciding with the straight traveling direction of the straddle carrier in the present embodiment. The number of the transverse micro-motion devices 3 can be two, and the transverse micro-motion devices are arranged at intervals along the longitudinal direction. The spacing distance of the two transverse micro-motion devices 3 can be set according to the sizes of the lifting appliance and the straddle carrier, for example, the spacing distance of the two transverse micro-motion devices 3 in the longitudinal direction is 5.5-6 m. When the two lateral micro-motion devices 3 move in the same direction in the lateral direction, for example, to the right at the same time, referring to fig. 2, the spreader 101 can be driven to move to the right, and when the two lateral micro-motion devices 3 move to the right and left one by one, the spreader 101 can be driven to rotate in the horizontal plane.

Referring to fig. 6 and 7, the wheel frame in each of the above embodiments includes an upper support beam 203 and a lower support beam 205, the upper support beam 203 and the lower support beam 205 are connected by a rotating shaft 209, and since the upper support beam 203 is fixedly connected to the vehicle frame 108, the lower support beam 205 can rotate along the rotating shaft 209 as a movable end. As the suspension cylinder 204 lifts up, the lower support beam 205 is driven to rotate along the rotation shaft 209, for example, in fig. 6, the lower support beam 205 rotates counterclockwise along the rotation shaft 209 by a certain angle, so that the entire wheel frame extends in the height direction (as shown in fig. 5). When the suspension cylinder 204 is contracted, that is, the suspension cylinder 204 descends, the lower support beam 205 is driven to rotate clockwise along the rotating shaft 209 by a certain angle, so that the whole wheel frame is shortened in the height direction. The upper support beam 203 and the lower support beam 205 in this embodiment form an approximately laterally open U-shape, or an inverted C-shape.

In each of the above embodiments, the wheel assembly further includes a wheel set having two wheels symmetrically disposed in the transverse direction. Such as a left-right symmetrical wheel in fig. 7, including a tire 206 and a rim 207. Most straddle carriers in the prior art use a single wheel as the wheel assembly, and the wheels in the present embodiment are provided as pairs, so that the wheel size can be reduced (for example, the diameter of the tire 206 is not more than 1.2m), and the wheel pressure can be reduced. The two wheels form a wheel set as a wheel component, a plurality of wheel components are symmetrically distributed at the bottom of the straddle carrier, namely, the front end of the straddle carrier is provided with the wheel components which are transversely symmetrical, and the middle part and the rear end of the straddle carrier are also respectively provided with the wheel components which are transversely symmetrical. The wheel components which are transversely symmetrical are connected through wheel shafts to form a 3-wheel-shaft straddle carrier with the front end, the middle part and the rear end. As shown in fig. 4, the present embodiment further includes a 4-axle straddle carrier, which can further reduce wheel pressure and wear consumption of the wheels.

In the above embodiment, the symmetrical tires 206 of the wheel set are connected by the driving axle 208, which includes a differential mechanism and a hydraulic multi-disc brake disc. In addition, when the driving motor 201 is further added to the wheel assembly, a reduction gear may be provided in the transaxle 208. The straddle carrier of this embodiment is either 3 axles, i.e. 12 wheels, or 4 axles, i.e. 16 wheels. The drive motors 201 may be symmetrically distributed in the wheel assembly. As shown in fig. 1 and 2, specifically, when the straddle carrier is a 3-wheel axle, the central symmetrical wheel assemblies are respectively provided with a driving motor 201, and the central wheel assembly is used as the driving wheel assembly 104. As shown in fig. 4, when the straddle carrier is a 4-wheel axle, two symmetrical sets of four wheel assemblies are respectively provided with a driving motor 201, and the two sets of wheel assemblies in the middle are used as the driving wheel assemblies 104. In addition, the wheel assembly further includes a swing mechanism 202, and the wheel assembly also serves as a steering wheel assembly 102, and the steering and the leaning of the straddle carrier can be accomplished by the arrangement of the driving wheel assembly 104 and the steering wheel assembly 102 (as shown in fig. 8 and 9)

In the above embodiments, the driving motor 201 may be a water-cooled, liquid-cooled or air-cooled motor, and the swing mechanism 202 may be in a gear ring driving mode, a hydraulic cylinder driving mode or an electric push rod driving mode by using a servo motor. The upper support beam 203 may serve as a slewing support for the wheelset. The suspension cylinder 204 has a jacking function and can also play a role in leveling wheel pressure. In addition, the straddle carrier of the embodiment also comprises a power cabinet 103, an electric control cabinet and a hydraulic station 105. A cab 107 may also be provided on the straddle carrier for a human operator to drive if desired.

The following description will be given of the boxing and transportation operation of the straddle carrier by taking the straddle carrier in the above embodiments as an example, and the following process is only an exemplary description and is not to be construed as limiting the present invention.

Boxing operation:

before the straddle carrier does not enter the container area, the suspension cylinder 204 is adjusted to a certain height to ensure that a gap of 80-150mm exists between the spreader 101 and the container 106 to be hoisted in the height direction, the driving motor 201 acts to move the whole straddle carrier to make the lock pin holes on the spreader 101 and the container 106 be in the same vertical plane, and the transverse micro-motion device 3 can further help to adjust the transverse distance so that the transfer pin on the spreader is positioned right above the lock pin hole (as shown in fig. 1 and 2 for the alignment state of the spreader 101 and the container 106). When aligned in position, the suspension cylinder 204 is lowered to allow the pivot pins of the spreader 101 to enter the lock pin holes of the container 106 and pivot closed. After the above process is completed, the suspension cylinder 204 is lifted, and as shown in fig. 5, there is a gap of 150 and 200mm between the bottom of the container 106 and the ground.

And (3) transportation operation:

when the spreader 101 with the container 106 meets the clearance of 150-.

Unloading the box:

after reaching the designated location, the container 106 is unloaded, which is equivalent to the reverse process of the container loading operation, and will not be described herein.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing is a more detailed description of the invention, taken in conjunction with the specific embodiments thereof, and that no limitation of the invention is intended thereby. Various changes in form and detail, including simple deductions or substitutions, may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A straddle carrier comprises a plurality of wheel assemblies distributed at the bottom of the straddle carrier and a lifting appliance, it is characterized in that the straddle carrier omits an independent lifting mechanism for lifting a spreader, the spreader is provided with a transfer pin matched with a lock pin hole on a container, each wheel component comprises a suspension oil cylinder with a jacking function and a wheel frame, the suspension oil cylinder is arranged on the wheel frame, when the suspension oil cylinder is at a first jacking height, the spreader is positioned at a first fixed height which is adapted to the height of the container to be hoisted, so that the rotating pins on the spreader can be locked into the locking pin holes in the container, and when the suspension oil cylinder is at a second jacking height, the lifting appliance is jacked to a second fixed height, and the second fixed height is higher than the first fixed height.

2. The straddle carrier according to claim 1, wherein the spreader is at a first fixed height corresponding to the height of a pre-hoisted container on the ground.

3. The straddle carrier according to claim 2, wherein the bottom of the container is spaced from the ground by 150-200mm when the spreader is locked into the locking pin hole of the container and the spreader is at the second fixed height.

4. The straddle carrier of claim 1, further comprising a frame, said spreader being mounted to said frame, said wheel frame being fixedly connected to said frame.

5. The straddle carrier according to claim 4, further comprising a lateral micro-motion device fixedly connected to the spreader, for driving the spreader to move in a lateral direction perpendicular to the advancing direction of the straddle carrier to adjust the position of the spreader in the lateral direction.

6. The straddle carrier according to claim 5, wherein the transverse micro-motion device comprises a roller, a connecting frame and an actuating cylinder, the frame has a fixed cross member extending in the transverse direction, the roller is located on the fixed cross member, the actuating cylinder is connected with the roller in the transverse direction, the connecting frame is fixedly connected with the roller and the sling, and the roller is driven to roll on the fixed cross member in the transverse direction through the expansion and contraction of the cylinder, so that the sling moves in the transverse direction.

7. The straddle carrier according to claim 5, wherein two of said lateral micromotion devices are provided at a spacing longitudinally of said spreader.

8. The straddle carrier according to claim 4, wherein the wheel frame comprises an upper support beam and a lower support beam for connecting a rotating shaft of the upper support beam and the lower support beam, the upper support beam is fixedly connected with the frame, the upper end of the suspension cylinder is fixedly connected with the upper support beam, the lower end of the suspension cylinder is fixedly connected with the lower support beam, and the lower support beam can rotate along the rotating shaft by the expansion and contraction of the suspension cylinder to extend or shorten the height of the wheel frame.

9. The straddle carrier according to any one of claims 1-8, wherein the wheel assembly further comprises a wheel set having two wheels arranged symmetrically in the transverse direction.

10. The straddle carrier according to claim 9, wherein a drive axle is connected between two of said wheels, said drive axle comprising a differential and an internal hydraulic multiple-disc brake disc.

11. The straddle carrier according to any one of claims 1-8, wherein the plurality of wheel assemblies comprises a drive wheel assembly and a steering wheel assembly.

12. The straddle carrier according to any of claims 1-8, further being provided with a cab.