CN105236308A - Forklift capable of running in two directions - Google Patents

Abstract

The invention relates to a forklift that can travel in both directions, including a forklift cab, a driving cab, an engine assembly, a driving system, a transmission system, a steering system, a braking system, a mast system and a hydraulic system; the driving system includes a vehicle frame, Front wheels, rear wheels, steering axle and driving axle, the front end of the frame is connected to the steering axle through the suspension, the rear end of the frame is rigidly connected to the driving axle, and the driving cab and forklift cab are respectively arranged on the front and rear sides of the frame. The engine assembly is fixed at the front end of the frame and connected with the torque converter, transmission, universal joint, transmission shaft and drive axle in turn; the driving cab and the forklift cab are each equipped with a set of driving gear shifting mechanisms , driving shift lock mechanism, steering control mechanism, brake control mechanism and emergency brake control mechanism, the forklift cab is also equipped with a mast system control mechanism and a working brake mechanism. The forklift can not only run fast on ordinary roads but also carry out transport work, and has high working efficiency.

Description

bidirectional forklift

technical field

The invention relates to a forklift, in particular to a bidirectionally traveling forklift.

Background technique

Forklifts are common transport vehicles and an important logistics tool to realize the mechanization of loading and unloading operations and improve labor productivity. When carrying out transportation or traction and hauling operations between two places in a large area and long distance, forklifts need to have rapid site transfer capabilities, and must be able to keep up with the speed of general transport fleets. At the same time, forklifts must also have certain field operation capabilities. Therefore, in order for the forklift to meet the above requirements, it must have the ability to walk both construction machinery and automobiles.

A general car is composed of the most basic cab, engine assembly, driving system, transmission system, steering system and braking system. Among them, the driving system includes the frame, front wheels, rear wheels, front axle and rear axle. There is a driving gear shift mechanism and a driving shift locking mechanism of the transmission system, a steering control mechanism of the steering system, a brake control mechanism of the braking system and an emergency brake control mechanism. On this basis, a general forklift adds a door gantry system (for construction operations such as lifting and turning) and hydraulic system (to provide power for the gantry system), and the operating mechanism and working brake mechanism of the gantry system are added in the cab.

For large-scale, long-distance transportation or traction between two places, the existing forklifts mainly have the following disadvantages: 1) The front and rear axles are directly rigidly connected to the frame, and there is no shock absorption system. Large-scale and long-distance site transfer will inevitably affect the ride comfort, safety and ride comfort of the vehicle, and will also affect the wearing parts on the vehicle; 3) If a large-scale, long-distance driving operation is carried out directly, the mast system set in front of the driver will affect the driver's vision, and it is difficult to avoid pedestrians or obstacles; 4) Forklifts working indoors The maximum travel speed is about 30km/h, and the maximum travel speed of off-road forklifts working in the field is about 40km/h, which is low.

To sum up, limited by the above structural features, existing forklifts cannot simultaneously meet the two requirements of quickly arriving at the job site and performing forklift operations at a prescribed speed in accordance with safe operating procedures during normal operations.

Contents of the invention

The purpose of the present invention is to provide a forklift that can travel in both directions, which can not only run quickly on ordinary roads but also carry out transportation work, solve the problem of inconvenient movement in the long-distance transfer work site of the existing forklift, and expand the adaptability of the forklift , Improve the working efficiency of the forklift.

The technical scheme adopted in the present invention is:

A forklift that can travel in both directions, including a forklift cab, an engine assembly, a driving system, a transmission system, a steering system, a braking system, a mast system and a hydraulic system; the driving system includes a frame, front wheels, rear wheels, front Axle and rear axle; forklift cab is equipped with driving gear shift mechanism and driving shift locking mechanism of transmission system, steering control mechanism of steering system, brake control mechanism and emergency brake control mechanism of braking system, forklift The operating mechanism and working brake mechanism of the gantry system are also provided in the cab; the characteristic is that the forklift cab is set at the rear end of the frame, the front end of the frame is equipped with a driving cab, the front axle is a steering axle, and the rear axle is It is a drive axle, the front end of the frame is connected to the steering axle through the suspension, the rear end of the frame is rigidly connected to the drive axle, the engine assembly is fixed on the front end of the frame and connected with the hydraulic torque converter, transmission and drive system in turn. Universal joint connection, the universal joint is connected with the drive axle through the transmission shaft; there is a set of independent driving gear shift mechanism, driving shift lock mechanism, steering control mechanism, brake control mechanism and emergency brake in the driving cab. manipulation mechanism.

Further, the steering system includes two sets of steering control mechanisms, two sets of steering switching mechanisms, power steering mechanisms, steering gears and steering transmission mechanisms, the two sets of steering control mechanisms are respectively connected to the steering gear through two sets of steering switching mechanisms, and the two sets of steering switching mechanisms The mechanism can separately control the on-off between the two sets of steering mechanisms and the steering gear. The steering gear is connected to the steering transmission mechanism and drives the wheels to turn through the steering transmission mechanism. The power steering mechanism is used to reduce the driver's effort when operating the steering mechanism. The operating ends of the two sets of steering switching mechanisms are respectively located in the forklift cab and the driving cab.

Further, both sets of steering switching mechanisms include a combination sleeve operating rod, a combination sleeve, a spline hub, a combination ring gear, a first gear and a second gear, wherein the combination sleeve is sleeved on the spline hub, and the combination ring gear is fixed on the second gear. On the first gear; the operating ends of the operating rods of the two sets of steering switching mechanisms are respectively located in the forklift cab and the driving cab, and the spline hubs of the two steering switching mechanisms are respectively fixed on the output shafts of the two steering operating mechanisms. The first gear of the steering switching mechanism is respectively emptied on the output shafts of the two sets of steering control mechanisms. The operating rod of the combined sleeve is connected with the combined sleeve and can drive the combined sleeve to move axially along the spline hub to mesh with or separate from the combined ring gear. The second gears of the two steering switching mechanisms are fixed on the input shaft of the steering gear, the first gear and the second gear of one steering switching mechanism are directly meshed, and the first gear and the second gear of the other steering switching mechanism Mesh through the third gear.

Further, a self-locking mechanism is provided on the combined sleeve operating rods of the two sets of steering switching mechanisms, and the self-locking mechanism includes a locking block, a compression spring and a steel ball, and two side-by-side grooves are arranged on the combined sleeve operating rods. , the locking block is set on the operating rod of the combination sleeve, the compression spring and the steel ball are set inside the locking block, the compression spring always presses the steel ball, and the steel ball is always in contact with the operation rod of the combination sleeve. When the steel ball is stuck in different concave When in the slot, the steering shift mechanism is in a different locked state.

Further, the transmission is provided with a driving gear for high-speed driving and a working gear for low-speed work. The driving gear includes four forward gears and one reverse gear, and the working gear includes two forward gears and one reverse gear.

Furthermore, the vehicle frame includes two longitudinal beams and several cross beams fixed as a whole, the front end of the vehicle frame is provided with lifting lugs connected with the suspension, and the rear end of the vehicle frame is provided with cylindrical grooves and circular bearings connected with the drive axle Cover, the engine assembly is fixed on the beam at the front end of the frame.

Further, the suspension is a longitudinal leaf spring suspension.

Further, the engine assembly is a diesel engine assembly.

Further, the front wheels are pneumatic tires, and the rear wheels are solid tires.

The beneficial effects of the present invention are:

1. The forklift is equipped with a cab at the front and back, and each cab has an independent control system, which can realize two-way driving. The control field of view will not be blocked during high-speed driving and low-speed operation, and the driving is safe; when driving at high speed, the front and rear When operating at low speed, the rear is front-drive, and the clutch is replaced by a hydraulic torque converter (generally, the engine assembly is connected with the clutch, transmission, universal joint, transmission shaft and drive axle in turn), and the hydraulic torque converter is locked and unlocking, forming two power transmission modes of pure mechanical transmission and hydromechanical transmission to meet the power requirements required for high-speed driving and low-speed operation respectively. , Infinitely variable speed and torque, with good automatic adaptability, at the same time, the liquid in the hydraulic transmission has a shock absorption effect, greatly reducing the dynamic load generated in the transmission system, improving the comfort and smoothness of the forklift and the use of mechanical components Life; the steering axle is connected to the frame through the suspension to ensure the smoothness of driving, and the drive axle is rigidly connected to the frame to ensure the load-carrying capacity during the forklift operation.

2. The steering system of a general forklift includes a steering control mechanism, a power steering mechanism (often using a hydraulic power assist type), a steering gear (often using a rack and pinion type) and a steering transmission mechanism (often using an integral steering trapezoid), the forklift adds A set of independent steering control mechanism and two sets of steering switching mechanisms control the on-off between the two sets of steering control mechanisms and the steering gear, and select the corresponding steering control mechanism and steering gear according to the current working status of the forklift. The steering of the forklift is controlled through the steering mechanism, and the other steering mechanism is disconnected from the steering gear and cannot control the steering of the forklift. This realizes the switching of the steering mechanism and prevents the two sets of steering mechanisms from interfering with each other; The operating ends of the switching mechanism are respectively located in the forklift cab and the driving cab to facilitate the steering switching operation.

3. The output shaft of the steering mechanism and the input shaft of the steering gear are connected through the combination sleeve, the combination ring gear and the first gear and the second gear. There is also a third gear, the third gear is set to ensure the coordination of left and right turns when the forklift is driving in both directions), wherein, the first gear is idle on the output shaft of the steering control mechanism, and cannot directly transmit the output torque of the steering control mechanism, combined with The sleeve is set on the spline hub, which can transmit the output torque of the steering control mechanism and can also move axially along the spline hub to approach or move away from the coupling ring gear driven by the operation rod of the coupling sleeve. When the coupling sleeve and the coupling ring gear need to be meshed, The combination sleeve first synchronizes the rotation speed of the combination ring gear through friction, and then meshes. At this time, the first gear can rotate and transmit the output torque of the steering control mechanism driven by the combination ring gear. The steering control mechanism communicates with the steering gear, and the steering The steering mechanism can perform steering operations; the two sets of steering switching mechanisms realize the sharing of one steering actuator by the two sets of steering manipulation mechanisms, ensuring the safety performance of the forklift steering.

4. When the steel ball is stuck in the groove, the operation rod of the combination sleeve can be fixed so that it cannot move freely, and the steering switching mechanism is locked. The two locking states of the steering switching mechanism correspond to the connection and disconnection of the steering control mechanism, ensuring driving safety.

5. The driving gear and working gear in the transmission work at high-speed driving and low-speed working respectively, which can obviously increase the driving speed of the forklift while ensuring the working performance, so that the forklift can carry out large-scale and long-distance site transfer.

6. The frame structure is simple, which reduces the weight of the car body.

7. The leaf spring suspension has simple structure, good shock absorption performance, and is suitable for occasions with heavy loads.

8. The diesel engine has a large torque and good economic performance, which can not only drive fast on ordinary roads but also carry out handling work.

9. The front wheels use pneumatic tires to improve ride comfort, and the rear tires use solid tires to increase the load-carrying capacity of the wheels.

Description of drawings

Fig. 1 is a front view of an embodiment of the present invention.

Fig. 2 is a top view of an embodiment of the present invention.

Fig. 3 is a layout diagram of the chassis in the embodiment of the present invention.

Fig. 4 is a schematic diagram of the steering switching mechanism in the embodiment of the present invention.

Fig. 5 is a schematic diagram of the combination sleeve operation lever and the self-locking mechanism in the embodiment of the present invention.

1-front wheel; 2-rear wheel; 3-gantry system; 4-hydraulic system; 5-forklift cab; 6-driving cab; 7-transmission axle; 8-frame; 9-drive axle; 10- Drive shaft; 11-steering control mechanism (steering wheel); 12-universal joint; 13-transmission; 14-torque converter; 15-engine assembly; 16-self-locking mechanism; - the output shaft of the steering mechanism; 19 - the coupling sleeve; 20 - the spline hub; 21 - the coupling ring gear; 22 - the first gear; 23 - the input shaft of the steering gear; 24 - the second gear; 25 - the third gear ; 26-lock block; 27-compression spring; 28-steel ball.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, a forklift that can travel in both directions includes a forklift cab 5, a driving cab 6, an engine assembly 15, a traveling system, a transmission system, a steering system, a braking system, a mast system 3 and a hydraulic system 4; as shown in Figure 3, driving system comprises vehicle frame 8, front wheel 1, rear wheel 2, front axle and rear axle, and front axle is steering axle 7, and rear axle is driving axle 9, and the front end of vehicle frame 8 passes suspension The frame is connected to the steering axle 7, the rear end of the vehicle frame 8 is rigidly connected to the drive axle 9, the driving cab 6 and the forklift cab 5 are respectively arranged at the front and rear ends of the vehicle frame 8, and the engine assembly 15 is fixed on the bottom of the vehicle frame 8. The front end is connected with the hydraulic torque converter 14, transmission 13 and universal joint 12 of the transmission system in turn, and the universal joint 12 is connected with the drive axle 9 through the transmission shaft 10; the driving gear of the transmission system is arranged in the forklift cab 5 The shift mechanism and the driving shift lock mechanism, the steering control mechanism 11 of the steering system, the brake control mechanism and the emergency brake control mechanism of the braking system, the forklift cab 5 is also provided with the control mechanism of the mast system 3 and The working braking mechanism is provided with a set of independent driving gear shift mechanism, driving shift locking mechanism, steering mechanism 11, braking mechanism and emergency braking mechanism in the driving cab 6 .

In the present invention, the braking system, the mast system 3 and the hydraulic system 4 are conventional systems, and the configuration of an ordinary forklift can be adopted. The driving gear shift mechanism, the driving shift locking mechanism, the steering mechanism 11, The brake control mechanism, the emergency brake control mechanism, the control mechanism and the working brake mechanism of the gantry system 3 are all conventional mechanisms, and the configuration of an ordinary forklift can be adopted. The transmission system only replaces the conventional clutch with a hydraulic transformer. Torque device 14 (all the other remain unchanged), change is little, need not go into details one by one to braking system, mast system 3, hydraulic system 4 and transmission system and its operating mechanism respectively at this. Because there is a problem of steering coordination in two-way driving, the improvements made by the present invention to the forklift are mainly concentrated in the driving system and the steering system.

The forklift is equipped with a cab at the front and back, and each cab has an independent control system, which can realize two-way driving. The control field of view will not be blocked during high-speed driving and low-speed operation, and the driving is safe; When working at low speed, the rear is front-drive, and the clutch is replaced by a hydraulic torque converter 14 (generally, the engine assembly 15 is connected with the clutch, the transmission 13, the universal joint 12, the drive shaft 10 and the drive axle 9 in turn), and the hydraulic torque converter The locking and unlocking of the torque converter 14 form two power transmission modes of pure mechanical transmission and hydromechanical transmission to meet the power requirements for high-speed driving and low-speed operation respectively. The hydraulic torque converter 14 can Automatically and steplessly change speed and torque within a certain range, and have good automatic adaptability. At the same time, the liquid in the hydraulic transmission has a shock-absorbing effect, which greatly reduces the dynamic load generated in the transmission system and improves the comfort and smoothness of the forklift. performance and the service life of mechanical parts; the steering axle 7 is connected with the vehicle frame 8 through the suspension to ensure the smoothness of driving, and the drive axle 9 is rigidly connected with the vehicle frame 8 to ensure the carrying capacity during the fork-taking operation.

In this embodiment, the steering system of the present invention includes two sets of steering control mechanisms 11, two sets of steering switching mechanisms, power steering mechanisms, steering gears and steering transmission mechanisms, and the two sets of steering control mechanisms 11 are respectively connected by two sets of steering switching mechanisms and The steering gear is connected, and the two sets of steering switching mechanisms can respectively control the on-off between the two sets of steering control mechanisms 11 and the steering gear. The steering gear is connected with the steering transmission mechanism and drives the wheels to turn through the steering transmission mechanism. When operating the steering mechanism 11, the operating ends of the two sets of steering switching mechanisms are located in the forklift cab 5 and the driving cab 6 respectively. The steering system of a general forklift includes a steering control mechanism 11, a power steering mechanism (often adopting a hydraulic power assist type), a steering gear (often adopting a rack and pinion type) and a steering transmission mechanism (often adopting an integral steering trapezoid), and the forklift adds a One set of independent steering mechanism 11 and two sets of steering switching mechanisms, the two sets of steering switching mechanisms control the on-off between the two sets of steering mechanisms 11 and the steering gear, and select the corresponding steering mechanism 11 according to the current working state of the forklift It communicates with the steering gear and controls the steering of the forklift through the steering mechanism. The other steering mechanism is disconnected from the steering gear and cannot control the steering of the forklift. This realizes the switching of the steering mechanism 11 and prevents the two sets of steering mechanisms 11 from interfering with each other. ; The operating ends of the two sets of steering switching mechanisms are respectively located in the forklift cab 5 and the driving cab 6 to facilitate the steering switching operation.

As shown in Figure 4, in this embodiment, the two sets of steering switching mechanisms all include a combination sleeve operating rod 17, a combination sleeve 19, a spline hub 20, a combination ring gear 21, a first gear 22 and a second gear 24, wherein , the combined sleeve 19 is set on the spline hub 20, and the combined ring gear 21 is fixed on the first gear 22; the operating ends of the combined sleeve operating lever 17 of the two sets of steering switching mechanisms are respectively located in the forklift cab 5 and the driving cab 6 , the spline hubs 20 of the two sets of steering switching mechanisms are respectively fixed on the output shafts 18 of the two sets of steering operating mechanisms, and the first gears 22 of the two sets of steering switching mechanisms are respectively emptied on the output shafts 18 of the two sets of steering operating mechanisms. The combination sleeve operating rod 17 is connected with the combination sleeve 19 and can drive the combination sleeve 19 to move axially along the spline hub 20 to mesh with or separate from the combination ring gear 21. The second gear 24 of the two sets of steering switching mechanisms are fixed on the input of the steering gear On the shaft 23, the first gear 22 and the second gear 24 of one set of the steering switching mechanism are directly meshed, and the first gear 22 and the second gear 24 of the other steering switching mechanism are meshed through the third gear 25.

The output shaft 18 of the steering mechanism and the input shaft 23 of the steering gear are connected through the combination sleeve 19 with the combination ring gear 21 and the first gear 22 and the second gear 24 two groups of gears (wherein one set of the first gear 22 and the second gear Also be provided with the 3rd gear 25 between the 2 gears 24, arranging the 3rd gear 25 is to guarantee the coordination of turning left and right when the forklift two-way driving), wherein, the first gear 22 is vacantly sleeved on the output shaft 18 of the steering mechanism, and cannot directly The output torque of the steering mechanism 11 is transmitted, and the coupling sleeve 19 is set on the spline hub 20, so that the output torque of the steering mechanism 11 can be transmitted, and it can also be driven by the coupling sleeve operating rod 17 to move axially along the spline hub 20 to approach or Far away from the combined ring gear 21, when the combined sleeve 19 and the combined ring gear 21 need to be meshed, the combined sleeve 19 first synchronizes the rotation speed of the combined ring gear 21 through friction, and then meshes. At this time, the first gear 22 is in the combined ring gear Driven by 21, the output torque of the steering mechanism 11 can be rotated and transmitted, the steering mechanism 11 is connected with the steering gear, and the steering mechanism 11 can perform steering operation; the combination sleeve operating rod 17, the combination sleeve 19, the spline hub 20, the combination gear The structure and connection method of the ring 21 and the first gear 22 are common technologies in automobile synchronizers, and will not be described in detail here; the two sets of steering switching mechanisms have realized that the two sets of steering control mechanisms 11 share a set of steering actuators, ensuring that the forklift Steering safety performance.

As shown in Figure 4, a self-locking mechanism 16 is provided on the combined sleeve operating rod 17 of the two sets of steering switching mechanisms, and as shown in Figure 5, the self-locking mechanism 16 includes a locking block 26, a compression spring 27 and a steel ball 28. There are two side-by-side grooves on the combined sleeve operating rod 17, the locking block 26 is set on the combined sleeve operating rod 17, the compression spring 27 and the steel ball 28 are arranged inside the locking block 26, and the compression spring 27 is always pressed Tighten the steel ball 28, and the steel ball 28 is always in contact with the combination sleeve operating rod 17. When the steel ball 28 is stuck in different grooves, the steering switching mechanism is in different locking states. When the steel ball 28 is stuck in the groove, the combination sleeve operating rod 17 can be fixed so that it cannot move freely, and the locking of the steering switching mechanism is realized. The two locking states of the steering switching mechanism correspond to the connection and disconnection of the steering control mechanism 11. The driving safety is guaranteed.

In this embodiment, the transmission 13 is provided with a driving gear for high-speed driving and a working gear for low-speed operation. The driving gear includes four forward gears and one reverse gear, and the working gear includes two forward gears and one reverse gear. The driving gear and the working gear in the transmission 13 work respectively during high-speed driving and low-speed operation, which obviously improves the driving speed of the forklift while ensuring the working performance, so that the forklift can carry out large-scale, long-distance site transfer.

As shown in Figure 3, in this embodiment, the vehicle frame 8 includes two longitudinal beams and several cross beams fixed as a whole, the front end of the vehicle frame 8 is provided with lifting lugs connected with the suspension, and the rear end of the vehicle frame 8 is provided with There is a cylindrical groove and a circular bearing cap connected with the drive axle 9, and the engine assembly 15 is fixed on the crossbeam at the front end of the vehicle frame 8. Vehicle frame 8 is simple in structure, has alleviated the dead weight of car body.

In this embodiment, the suspension is a vertical leaf spring suspension. The leaf spring suspension has simple structure, good shock absorption performance, and is suitable for occasions with heavy loads.

In this embodiment, the engine assembly 15 is a diesel engine assembly 15 . The diesel engine has large torque and good economic performance, which can not only drive fast on ordinary roads but also carry out work.

In this embodiment, the front wheel 1 is a pneumatic tire, and the rear wheel 2 is a solid tire. The front wheel 1 adopts pneumatic tires to improve the ride comfort, and the rear wheels 2 adopt solid tires to increase the carrying capacity.

The operation steps when the forklift is running fast are: the driver enters the driving cab 6 and locks the torque converter 14. At this time, it is a purely mechanical transmission with front and rear drives, and the combination sleeve in the driving cab 6 is operated. Rod 17 (Push the combination sleeve operating rod 17 backward, and the combination sleeve operation rod 17 will press the steel ball 28 out of the groove A and slide into the groove B), so that the steering mechanism 11 in the driving cab 6 communicates with the steering gear To play a steering role (combining sleeve 19 and coupling ring gear 21 mesh), the driver manipulates the steering wheel, brake pedal, accelerator pedal and other operating mechanisms to quickly transfer the forklift to the destination.

The operation steps when the forklift is carrying out the work are: toggle the combination sleeve operating lever 17 in the driving cab 6 (the combination sleeve operating lever 17 is pushed forward, the combination sleeve operating lever 17 presses the steel ball 28 out of the groove B and Sliding into the groove A), the steering mechanism 11 in the driving cab 6 is disconnected from the steering gear (the coupling sleeve 19 and the coupling ring gear 21 are engaged and separated), and at the same time, the hydraulic torque converter 14 is unlocked, and then enter the forklift driving room 5, move the combination sleeve operating lever 17 in the forklift cab 5 (pull the combination sleeve operating lever 17 backward, the combination sleeve operating lever 17 will press the steel ball 28 out of the groove A and slide into the groove B), so that The steering mechanism 11 in the forklift cab 5 communicates with the steering gear to play a steering role (the combination sleeve 19 and the combination ring gear 21 mesh). At this time, it is a hydraulic mechanical transmission and the rear is front-drive, and then through the control mechanism of a conventional car ( Driving gear shift mechanism, driving gear shift locking mechanism, steering control mechanism 11, brake control mechanism and emergency brake control mechanism) realize the movement, steering and braking of the forklift, and control the tilt through the control mechanism of the mast system 3 The hydraulic cylinder and the lifting hydraulic cylinder inside the mast realize the lifting of the goods by the fork and the forward and backward tilting for handling operations.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should belong to the protection scope of the appended claims of the present invention.

Claims (9)

1. A forklift that can travel in both directions, including a forklift cab, an engine assembly, a driving system, a transmission system, a steering system, a braking system, a mast system and a hydraulic system; the driving system includes a frame, front wheels, and rear wheels , front axle and rear axle; forklift cab is equipped with driving gear shift mechanism and driving shift locking mechanism of transmission system, steering control mechanism of steering system, brake control mechanism and emergency brake control mechanism of braking system , the forklift cab is also equipped with the operating mechanism of the mast system and the working brake mechanism; it is characterized in that: the forklift cab is set at the rear end of the frame, the front end of the frame is equipped with a driving cab, and the front axle is a steering axle. The rear axle is the drive axle, the front end of the frame is connected to the steering axle through the suspension, the rear end of the frame is rigidly connected to the drive axle, the engine assembly is fixed on the front end of the frame and connected with the hydraulic torque converter of the transmission system, The transmission is connected with the universal joint, and the universal joint is connected with the drive axle through the transmission shaft; there is a set of independent driving gear shift mechanism, driving shift lock mechanism, steering control mechanism, brake control mechanism and emergency control mechanism in the driving cab. brake operating mechanism. 2. The forklift that can travel in both directions as claimed in claim 1, wherein the steering system includes two sets of steering mechanisms, two sets of steering switching mechanisms, power steering mechanisms, steering gears and steering transmission mechanisms, and two sets of steering mechanisms The two sets of steering switching mechanisms are respectively connected with the steering gear, and the two sets of steering switching mechanisms can respectively control the on-off between the two steering manipulation mechanisms and the steering gear. The steering gear is connected with the steering transmission mechanism and drives the wheels to turn through the steering transmission mechanism. The power steering mechanism is used to reduce the force intensity of the driver when operating the steering mechanism. The operating ends of the two sets of steering switching mechanisms are respectively located in the forklift cab and the driving cab. 3. The forklift capable of traveling in both directions according to claim 2, characterized in that: the two sets of steering switching mechanisms each include a combination sleeve operating rod, a combination sleeve, a splined hub, a combination ring gear, a first gear and a second gear, Among them, the combined sleeve is set on the spline hub, and the combined ring gear is fixed on the first gear; the operating ends of the combined sleeve operating levers of the two sets of steering switching mechanisms are respectively located in the forklift cab and the driving cab, and the splines of the two sets of steering switching mechanisms The key hubs are respectively fixed on the output shafts of the two sets of steering control mechanisms, and the first gears of the two sets of steering switching mechanisms are respectively set on the output shafts of the two sets of steering control mechanisms. The sleeve moves axially along the spline hub to engage or separate from the combined ring gear. The second gears of the two sets of steering switching mechanisms are fixed on the input shaft of the steering gear, and the first gear and the second gear of one set of steering switching mechanisms are directly meshing, the first gear and the second gear of another set of steering switching mechanism are meshed through the third gear. 4. The forklift capable of traveling in both directions as claimed in claim 3, characterized in that: a self-locking mechanism is provided on the combined sleeve operating rods of the two sets of steering switching mechanisms, and the self-locking mechanism includes a locking block, a compression spring and a There are two parallel grooves on the steel ball and the operation rod of the combination sleeve. The locking block is set on the operation rod of the combination sleeve. The compression spring and the steel ball are arranged inside the locking block. The compression spring always compresses the steel ball, and the steel ball Always in contact with the operation rod of the combination sleeve, when the steel ball is stuck in different grooves, the steering switching mechanism is in different locking states. 5. The forklift that can travel in both directions as claimed in claim 1, wherein the transmission is provided with a driving gear for high-speed driving and a working gear for low-speed operation, and the driving gear includes four forward gears and one reverse gear, and the working gear The gears include two forward gears and one reverse gear. 6. The forklift that can travel in both directions according to claim 1, wherein the frame includes two longitudinal beams and several cross beams fixed as a whole, and the front end of the frame is provided with lifting lugs connected with the suspension. The rear end of the frame is provided with a cylindrical groove and a circular bearing cover connected with the drive axle, and the engine assembly is fixed on the beam at the front end of the frame. 7. The bi-directional forklift according to claim 1, characterized in that: the suspension is a vertical leaf spring suspension. 8. The bi-directional forklift according to claim 1, wherein the engine assembly is a diesel engine assembly. 9. The bidirectional forklift according to claim 1, wherein the front wheels are pneumatic tires, and the rear wheels are solid tires.