All-wheel steering system and straddle carrier

Abstract

The present application relates to the technical field of straddle carriers, and provides an all-wheel steering system and a straddle carrier, wherein the all-wheel steering system comprises: a main frame, a left travel mechanism and a right travel mechanism; the left travel mechanism comprises a left frame, a left front wheel frame, a left rear wheel frame, a left front wheel and a left rear wheel; the right travel mechanism comprises a right frame, a right front wheel frame, a right rear wheel frame, a right front wheel and a right rear wheel; a steering hydraulic system comprises a hydraulic steering gear and a left front hydraulic cylinder, a left rear hydraulic cylinder, a right front hydraulic cylinder and a right rear hydraulic cylinder, wherein the left front hydraulic cylinder is transmission-connected to the left front wheel frame, the left rear hydraulic cylinder is transmission-connected to the left rear wheel frame, the right front hydraulic cylinder is transmission-connected to the right front wheel frame, the right rear hydraulic cylinder is transmission-connected to the right rear wheel frame, and the hydraulic steering gear is used for oil supply and oil return of the left front hydraulic cylinder, the left rear hydraulic cylinder, the right front hydraulic cylinder and the right rear hydraulic cylinder; a first mechanical synchronization mechanism and a second mechanical synchronization mechanism, and the all-wheel steering system has low cost and high reliability.

Description

Technical Field

[0001] The present application relates to the technical field of straddle carriers, and more specifically, to an all-wheel steering system and a straddle carrier. Background Art

[0002] As a tire-type gantry crane, straddle carriers are characterized by light weight, high load-bearing capacity, low wheel pressure, flexibility and high efficiency. They are particularly suitable for the handling, transfer and loading and unloading of large, heavy and high-risk goods such as road and bridge prefabricated parts, energy storage cabinets, large steel structures and containers. Due to the high load of straddle carriers, tire wear becomes an important factor to consider in the steering control of straddle carriers. In order to further reduce the turning radius of straddle carriers and improve their maneuverability and adaptability to factory sites, straddle carriers generally adopt all-wheel steering. However, the portal structure of straddle carriers makes it impossible to arrange traditional integral axle steering mechanisms.

[0003] In the all-wheel steering system of the straddle carrier in the prior art, each wheel steering is equipped with an independent actuator, and the steering angle of each wheel is controlled by an electrical program, and the steering angle detection on each wheel is fed back to the controller to form a closed-loop control of the wheel steering angle. The all-wheel steering system of the straddle carrier in the prior art mainly has the following defects:

[0004] 1. The wheel angle requires high-precision detection components and high-precision, high-response control execution components, which is costly.

[0005] 2. When the electrical detection components fail or the circuit fails, the reliability of the straddle carrier steering system cannot be guaranteed. The electrical and hydraulic systems of the straddle carrier have long pipes and lines, and are electronically controlled. The steering angle data needs to be collected and used to adjust the steering actuators of each wheel. The steering response of the left and right wheels is poor.

[0006] In summary, the all-wheel steering system of the straddle carrier in the prior art has poor reliability and high cost. Summary of the invention

[0007] In view of this, the present application provides an all-wheel steering system to solve the technical problems of poor reliability and high cost of the all-wheel steering system of the straddle carrier in the prior art.

[0008] The present application provides an all-wheel steering system, wherein the all-wheel steering system comprises:

[0009] Main frame, left travel mechanism and right travel mechanism;

[0010] The left traveling mechanism comprises a left frame, a left front wheel frame, a left rear wheel frame, a left front wheel and a left rear wheel, wherein the left frame is connected to the left side of the main frame, the left front wheel frame is rotatably connected to the front end of the left frame, the left front wheel is mounted on the left front wheel frame, the left rear wheel frame is rotatably connected to the rear end of the left frame, and the left rear wheel is mounted on the left rear wheel frame;

[0011] The right traveling mechanism comprises a right frame, a right front wheel frame, a right rear wheel frame, a right front wheel and a right rear wheel, wherein the right frame is connected to the right side of the main frame, the right front wheel frame is rotatably connected to the front end of the right frame, the right front wheel is mounted on the right front wheel frame, the right rear wheel frame is rotatably connected to the rear end of the right frame, and the right rear wheel is mounted on the right rear wheel frame;

[0012] A steering hydraulic system comprises a hydraulic steering gear and a left front hydraulic cylinder, a left rear hydraulic cylinder, a right front hydraulic cylinder and a right rear hydraulic cylinder connected to the hydraulic steering gear, wherein the left front hydraulic cylinder is drivingly connected to the left front wheel frame, the left rear hydraulic cylinder is drivingly connected to the left rear wheel frame, the right front hydraulic cylinder is drivingly connected to the right front wheel frame, and the right rear hydraulic cylinder is drivingly connected to the right rear wheel frame, and the hydraulic steering gear is used for oil supply and oil return of the left front hydraulic cylinder, the left rear hydraulic cylinder, the right front hydraulic cylinder and the right rear hydraulic cylinder, so that when the left front hydraulic cylinder, the left rear hydraulic cylinder, the right front hydraulic cylinder and the right rear hydraulic cylinder are telescopically moved, the left front wheel frame and the right front wheel frame can be driven to rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left rear wheel frame and the right rear wheel frame can rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left front wheel frame and the left rear wheel frame rotate synchronously in opposite directions with the same angle, and the right front wheel frame and the right rear wheel frame rotate synchronously in opposite directions with the same angle;

[0013] A first mechanical synchronization mechanism and a second mechanical synchronization mechanism, wherein the first mechanical synchronization mechanism is respectively connected to the left front wheel frame and the left rear wheel frame in transmission connection so as to enable the left front wheel frame and the left rear wheel frame to rotate synchronously at the same angle in opposite directions; and the second mechanical synchronization mechanism is respectively connected to the right front wheel frame and the right rear wheel frame in transmission connection so as to enable the right front wheel frame and the right rear wheel frame to rotate synchronously at the same angle in opposite directions.

[0014] Further, the cylinder body of the left front hydraulic cylinder is hinged to the left frame, the piston rod of the left front hydraulic cylinder is drivingly connected to the left front wheel frame, the cylinder body of the left rear hydraulic cylinder is hinged to the left frame, the piston rod of the left rear hydraulic cylinder is drivingly connected to the left rear wheel frame, the cylinder body of the right front hydraulic cylinder is hinged to the right frame, the piston rod of the right front hydraulic cylinder is drivingly connected to the right front wheel frame, the cylinder body of the right rear hydraulic cylinder is hinged to the right frame, and the piston rod of the right rear hydraulic cylinder is drivingly connected to the right rear wheel frame;

[0015] The hydraulic steering gear has a first working oil port and a second working oil port, and the steering hydraulic system also includes a first main oil circuit, a second main oil circuit, a series oil circuit, a first connecting oil circuit, a second connecting oil circuit, a third connecting oil circuit and a fourth connecting oil circuit. The rodless chamber of the left front hydraulic cylinder is connected to the rodless chamber of the left rear hydraulic cylinder through the first connecting oil circuit, the rod chamber of the left front hydraulic cylinder is connected to the rod chamber of the left rear hydraulic cylinder through the second connecting oil circuit, the rodless chamber of the right front hydraulic cylinder is connected to the rodless chamber of the right rear hydraulic cylinder through the third connecting oil circuit, and the rod chamber of the right front hydraulic cylinder is connected to the rod chamber of the right rear hydraulic cylinder through the fourth connecting oil circuit. One end of the first main oil circuit is connected to the first working oil port, the other end of the first main oil circuit is connected to the first connecting oil circuit, one end of the second main oil circuit is connected to the second working oil port, the other end of the second main oil circuit is connected to the third connecting oil circuit, one end of the series oil circuit is connected to the second connecting oil circuit, and the other end of the series oil circuit is connected to the fourth connecting oil circuit. When the first working oil port serves as the oil supply port of the first main oil circuit, the second working oil port serves as the oil return port of the second main oil circuit. When the second working oil port serves as the oil supply port of the second main oil circuit, the first working oil port serves as the oil return port of the first main oil circuit.

[0016] Further, the all-wheel steering system includes a turning angle detection device for detecting the left front wheel, left rear wheel, right front wheel and right rear wheel, and the steering hydraulic system also includes an intermediate oil circuit, a first electrically controlled on-off valve, a second electrically controlled on-off valve and a third electrically controlled on-off valve, one end of the intermediate oil circuit is connected to the first connection point of the series oil circuit, and the other end of the intermediate oil circuit is connected to the second connection point of the second main oil circuit, the first electrically controlled on-off valve is arranged on the series oil circuit and is located between the first connection point and the fourth connection oil circuit, the second electrically controlled on-off valve is arranged on the intermediate oil circuit, the third electrically controlled on-off valve is arranged on the second main oil circuit and is located between the second connection point and the third connection oil circuit, and the turning angle detection device is signal-connected to the first electrically controlled on-off valve, the second electrically controlled on-off valve and the third electrically controlled on-off valve.

[0017] Further, the left travel mechanism also includes a left front link mechanism and a left rear link mechanism connected to the left frame, the piston rod of the left front hydraulic cylinder is connected to the left front link mechanism, the left front link mechanism is connected to the left front wheel frame, the piston rod of the left rear hydraulic cylinder is connected to the left rear link mechanism, and the left rear link mechanism is connected to the left rear wheel frame;

[0018] The right travel mechanism also includes a right front connecting rod mechanism and a right rear connecting rod mechanism connected to the right frame, the piston rod of the right front hydraulic cylinder is connected to the right front connecting rod mechanism, the right front connecting rod mechanism is connected to the right front wheel frame, the piston rod of the right rear hydraulic cylinder is connected to the right rear connecting rod mechanism, and the right rear connecting rod mechanism is connected to the right rear wheel frame.

[0019] Furthermore, the left front connecting rod mechanism includes a first connecting rod and a second connecting rod, the first end of the first connecting rod is hinged to the left frame, the second end of the first connecting rod is hinged to the first end of the second connecting rod, the second end of the second connecting rod is hinged to the left front wheel frame, and the piston rod of the left front hydraulic cylinder is connected to the second connecting rod; the left rear connecting rod mechanism includes a third connecting rod and a fourth connecting rod, the first end of the third connecting rod is hinged to the left frame, the second end of the third connecting rod is hinged to the first end of the fourth connecting rod, the second end of the fourth connecting rod is hinged to the left rear wheel frame, and the piston rod of the left rear hydraulic cylinder is connected to the fourth connecting rod. The right front connecting rod mechanism comprises a fifth connecting rod and a sixth connecting rod, the first end of the fifth connecting rod is hinged to the right frame, the second end of the fifth connecting rod is hinged to the first end of the sixth connecting rod, the second end of the sixth connecting rod is hinged to the right front wheel frame, and the piston rod of the right front hydraulic cylinder is connected to the sixth connecting rod; the right rear connecting rod mechanism comprises a seventh connecting rod and an eighth connecting rod, the first end of the seventh connecting rod is hinged to the right frame, the second end of the seventh connecting rod is hinged to the first end of the eighth connecting rod, the second end of the eighth connecting rod is hinged to the right rear wheel frame, and the piston rod of the right rear hydraulic cylinder is connected to the eighth connecting rod.

[0020] Furthermore, the left front link mechanism, the left rear link mechanism, the right front link mechanism and the right rear link mechanism are all planar six-link mechanisms.

[0021] Further, the left front wheel frame is rotatably connected to the left frame via a first swivel support, the left rear wheel frame is rotatably connected to the left frame via a second swivel support, the right front wheel frame is rotatably connected to the right frame via a third swivel support, and the right rear wheel frame is rotatably connected to the right frame via a fourth swivel support.

[0022] Further, the first slewing support and the second slewing support each include a fixed ring fixedly connected to the left frame and a rotating ring rotatably connected to the corresponding fixed ring, the third slewing support and the fourth slewing support each include a fixed ring fixedly connected to the right frame and a rotating ring rotatably connected to the corresponding fixed ring, the first mechanical synchronization mechanism is a first inverse quadrilateral connecting rod synchronization mechanism or a first chain synchronization mechanism that is transmission-connected to the rotating ring of the first slewing support and the rotating ring of the second slewing support, and the second mechanical synchronization mechanism is a second inverse quadrilateral connecting rod synchronization mechanism or a second chain synchronization mechanism that is transmission-connected to the rotating ring of the third slewing support and the rotating ring of the fourth slewing support.

[0023] Further, the movable circle of the first slewing support is connected to a first sprocket, the movable circle of the second slewing support is connected to a second sprocket, the movable circle of the third slewing support is connected to a third sprocket, the movable circle of the fourth slewing support is connected to a fourth sprocket, the first mechanical synchronization mechanism is a first chain synchronization mechanism, and the second mechanical synchronization mechanism is a second chain synchronization mechanism;

[0024] The first mechanical synchronization mechanism comprises a first chain, a second chain, a first pull plate and a second pull plate, the first pull plate and the second pull plate are arranged crosswise with each other, the first ends of the first pull plate and the second pull plate are respectively oriented toward the front end of the left frame, and the second ends of the first pull plate and the second pull plate are respectively oriented toward the rear end of the left frame, the first chain is meshed with the first sprocket and the two ends of the first chain are respectively connected to the first ends of the first pull plate and the second pull plate, the second chain is meshed with the second sprocket and the two ends of the second chain are respectively connected to the second ends of the first pull plate and the second pull plate;

[0025] The second mechanical synchronization mechanism includes a third chain, a fourth chain, a third pull plate and a fourth pull plate, the third pull plate and the fourth pull plate are arranged crosswise with each other, the first end of each of the third pull plate and the fourth pull plate faces the front end of the right frame, and the second end of each of the third pull plate and the fourth pull plate faces the rear end of the right frame, the third chain is engaged with the third sprocket and the two ends of the third chain are respectively connected to the first ends of the third pull plate and the fourth pull plate, the fourth chain is engaged with the fourth sprocket and the two ends of the fourth chain are respectively connected to the second ends of the third pull plate and the fourth pull plate.

[0026] In addition, the present invention also provides a straddle carrier, wherein the straddle carrier comprises the above-mentioned all-wheel steering system.

[0027] The beneficial effects of the all-wheel steering system provided by the present invention are:

[0028] Compared with the prior art, in the all-wheel steering system provided by the present invention, by designing the steering hydraulic system, the first mechanical synchronization mechanism and the second mechanical synchronization mechanism, it is possible to drive the left front wheel frame and the right front wheel frame to rotate synchronously in the same direction and at unequal angles under the premise of satisfying the Ackerman formula, the left rear wheel frame and the right rear wheel frame to rotate synchronously in the same direction and at unequal angles under the premise of satisfying the Ackerman formula, the left front wheel frame and the left rear wheel frame to rotate synchronously in opposite directions and at the same angle, and the right front wheel frame and the right rear wheel frame to rotate synchronously in opposite directions and at the same angle. That is to say, the steering (especially synchronous steering) execution control of each wheel (left front wheel, left rear wheel, right front wheel and right rear wheel) can be achieved through a hydraulic cylinder with a simplified structure and a mechanical synchronization mechanism. There is no high-precision detection element and a high-precision, high-response actuator, and the cost is greatly reduced. The turning angle accuracy of the whole vehicle steering process is guaranteed by the mechanical connection points (such as connecting rod hinges, etc.) and the sealing performance of the hydraulic cylinder. It has high reliability, does not require signal transmission and program intervention, and has a fast steering response.

[0029] In a further solution, the all-wheel steering system includes a turning angle detection device for detecting the left front wheel, left rear wheel, right front wheel and right rear wheel. The function of the turning angle detection device is mainly to assist in detection and is only used for debugging and adjusting the initial turning angles of the wheels on both sides in case of leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic plan view of a partial structure of an all-wheel steering system according to an embodiment of the present application;

[0032] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0033] Figure 3 for Figure 1 The enlarged view of point B in the middle;

[0034] Figure 4 for Figure 1 Enlarged view of point C in the middle;

[0035] Figure 5 for Figure 1 The enlarged view of point D in the middle;

[0036] Figure 6A simplified schematic diagram of the main structure of an all-wheel steering system according to an embodiment of the present application;

[0037] Figure 7 A simplified schematic diagram of a steering hydraulic system of an all-wheel steering system according to an embodiment of the present application;

[0038] Figure 8 A partial schematic diagram of the steering hydraulic system of the all-wheel steering system according to an embodiment of the present application performing steering angle error compensation in a first situation;

[0039] Fig. 9 A partial schematic diagram of the steering hydraulic system of the all-wheel steering system according to an embodiment of the present application performing steering angle error compensation in the second situation;

[0040] Fig.10 FIG. 4 is a schematic diagram of steering wheels of a straddle carrier according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. One or more embodiments of the present application are exemplarily given in the drawings to make the understanding of the technical solution disclosed in the present application more accurate and thorough. However, it should be understood that the present application can be implemented in a variety of different forms and is not limited to the embodiments described below.

[0042] The same or similar numbers in the drawings of the present application correspond to the same or similar parts; in the description of the present application, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. This is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B.

[0044] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0045] See also Figures 1 to 7 The present invention provides an all-wheel steering system, especially an all-wheel steering system for a straddle carrier, but is not limited to an all-wheel steering system for a straddle carrier. Other types of vehicles and equipment, as long as they are applied with the all-wheel steering system provided by the present invention, will fall within the protection scope of the present invention, wherein the all-wheel steering system includes:

[0046] Main frame 1, left traveling mechanism and right traveling mechanism;

[0047] The left traveling mechanism comprises a left vehicle frame 2, a left front wheel frame 3, a left rear wheel frame 4, a left front wheel 5 and a left rear wheel 6. The left vehicle frame 2 is connected to the left side of the main vehicle frame 1, the left front wheel frame 3 is rotatably connected to the front end of the left vehicle frame 2, the left front wheel 5 is mounted on the left front wheel frame 3, the left rear wheel frame 4 is rotatably connected to the rear end of the left vehicle frame 2, and the left rear wheel 6 is mounted on the left rear wheel frame 4;

[0048] The right traveling mechanism includes a right frame 7, a right front wheel frame 8, a right rear wheel frame 9, a right front wheel 10 and a right rear wheel 11. The right frame 7 is connected to the right side of the main frame 1, the right front wheel frame 8 is rotatably connected to the front end of the right frame 7, the right front wheel 10 is mounted on the right front wheel frame 8, the right rear wheel frame 9 is rotatably connected to the rear end of the right frame 7, and the right rear wheel 11 is mounted on the right rear wheel frame 9. The main frame 1, the left frame 2 and the right frame 7 form the main structure of the all-wheel steering system.

[0049] The steering hydraulic system comprises a hydraulic steering gear 100 and a left front hydraulic cylinder 12, a left rear hydraulic cylinder 13, a right front hydraulic cylinder 14 and a right rear hydraulic cylinder 15 connected to the hydraulic steering gear 100. The left front hydraulic cylinder 12 is connected to the left front wheel frame 3 by transmission, the left rear hydraulic cylinder 13 is connected to the left rear wheel frame 4 by transmission, the right front hydraulic cylinder 14 is connected to the right front wheel frame 8 by transmission, and the right rear hydraulic cylinder 15 is connected to the right rear wheel frame 9 by transmission. The hydraulic steering gear 100 is used for the left front hydraulic cylinder 12, the left rear hydraulic cylinder 13, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15. The oil supply and oil return of the rear hydraulic cylinder 15 enable the left front hydraulic cylinder 12, the left rear hydraulic cylinder 13, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 to drive the left front wheel frame 3 and the right front wheel frame 8 to rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left rear wheel frame 4 and the right rear wheel frame 9 to rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left front wheel frame 3 and the left rear wheel frame 4 to rotate synchronously in opposite directions with the same angle, and the right front wheel frame 8 and the right rear wheel frame 9 to rotate synchronously in opposite directions with the same angle;

[0050] The first mechanical synchronization mechanism 200 and the second mechanical synchronization mechanism 300 are respectively connected to the left front wheel frame 3 and the left rear wheel frame 4 in transmission connection so as to enable the left front wheel frame 3 and the left rear wheel frame 4 to rotate synchronously in opposite directions and at the same angle; the second mechanical synchronization mechanism 300 is respectively connected to the right front wheel frame 8 and the right rear wheel frame 9 in transmission connection so as to enable the right front wheel frame 8 and the right rear wheel frame 9 to rotate synchronously in opposite directions and at the same angle.

[0051] In the all-wheel steering system provided by the present invention, by designing the steering hydraulic system, the first mechanical synchronization mechanism 200 and the second mechanical synchronization mechanism 300, it is possible to drive the left front wheel frame 3 and the right front wheel frame 8 to rotate synchronously in the same direction and at the same angle, the left rear wheel frame 4 and the right rear wheel frame 9 to rotate synchronously in the same direction and at the same angle, the left front wheel frame 3 and the left rear wheel frame 4 to rotate synchronously in opposite directions and at the same angle, and the right front wheel frame 8 and the right rear wheel frame 9 to rotate synchronously in opposite directions and at the same angle. In other words, the steering (especially synchronous steering) execution control of each wheel (left front wheel 5, left rear wheel 6, right front wheel 10 and right rear wheel 11) can be achieved through the simplified hydraulic cylinder and the mechanical synchronization mechanism. There is no high-precision detection element and high-precision, high-response actuator, and the cost is greatly reduced. The turning angle accuracy of the whole vehicle steering process is guaranteed by the mechanical connection points (such as connecting rod hinges, etc.) and the sealing performance of the hydraulic cylinder. It has high reliability, does not require signal transmission and program intervention, and has a fast steering response.

[0052] According to one embodiment of the present application, the cylinder body of the left front hydraulic cylinder 12 is hinged to the left frame 2, the piston rod of the left front hydraulic cylinder 12 is transmission-connected to the left front wheel frame 3, the cylinder body of the left rear hydraulic cylinder 13 is hinged to the left frame 2, the piston rod of the left rear hydraulic cylinder 13 is transmission-connected to the left rear wheel frame 4, the cylinder body of the right front hydraulic cylinder 14 is hinged to the right frame 7, the piston rod of the right front hydraulic cylinder 14 is transmission-connected to the right front wheel frame 8, the cylinder body of the right rear hydraulic cylinder 15 is hinged to the right frame 7, and the piston rod of the right rear hydraulic cylinder 15 is transmission-connected to the right rear wheel frame 9; the hydraulic steering gear 100 has a first working oil Port 101 and a second working oil port 102, the steering hydraulic system also includes a first main oil circuit 16, a second main oil circuit 17, a series oil circuit 18, a first connecting oil circuit 19, a second connecting oil circuit 20, a third connecting oil circuit 21 and a fourth connecting oil circuit 22, the rodless chamber of the left front hydraulic cylinder 12 is connected to the rodless chamber of the left rear hydraulic cylinder 13 through the first connecting oil circuit 19, the rod chamber of the left front hydraulic cylinder 12 is connected to the rod chamber of the left rear hydraulic cylinder 13 through the second connecting oil circuit 20, the rodless chamber of the right front hydraulic cylinder 14 is connected to the rodless chamber of the right rear hydraulic cylinder 15 through the third connecting oil circuit 21, The rod chamber of the right front hydraulic cylinder 14 is connected to the rod chamber of the right rear hydraulic cylinder 15 through the fourth connecting oil circuit 22, one end of the first main oil circuit 16 is connected to the first working oil port 101, the other end of the first main oil circuit 16 is connected to the first connecting oil circuit 19, one end of the second main oil circuit 17 is connected to the second working oil port 102, the other end of the second main oil circuit 17 is connected to the third connecting oil circuit 21, one end of the series oil circuit 18 is connected to the second connecting oil circuit 20, the other end of the series oil circuit 18 is connected to the fourth connecting oil circuit 22, and the first working oil port 101 is used as the supply of the first main oil circuit 16. The oil port, the second working oil port 102 serves as the return oil port of the second main oil circuit 17; when the second working oil port 102 serves as the oil supply port of the second main oil circuit 17, the first working oil port 101 serves as the return oil port of the first main oil circuit 16. The internal structure of the hydraulic steering gear 100 is a known technology and will not be described in detail here. Of course, the hydraulic steering gear 100 can also be connected to components such as an oil pump and an oil tank through pipelines, wherein one of the two components of the "transmission connection" can drive the other component, and the two components can be directly connected or indirectly connected through additional components.

[0053] According to one embodiment of the present application, the left travel mechanism further includes a left front link mechanism and a left rear link mechanism connected to the left frame 2, the piston rod of the left front hydraulic cylinder 12 is connected to the left front link mechanism, the left front link mechanism is connected to the left front wheel frame 3, the piston rod of the left rear hydraulic cylinder 13 is connected to the left rear link mechanism, and the left rear link mechanism is connected to the left rear wheel frame 4;

[0054] The right travel mechanism also includes a right front connecting rod mechanism and a right rear connecting rod mechanism connected to the right frame 7. The piston rod of the right front hydraulic cylinder 14 is connected to the right front connecting rod mechanism, and the right front connecting rod mechanism is connected to the right front wheel frame 8. The piston rod of the right rear hydraulic cylinder 15 is connected to the right rear connecting rod mechanism, and the right rear connecting rod mechanism is connected to the right rear wheel frame 9.

[0055] According to a specific embodiment of the present application, the left front link mechanism includes a first link 28 and a second link 29, the first end of the first link 28 is hinged to the left frame 2, the second end of the first link 28 is hinged to the first end of the second link 29, the second end of the second link 29 is hinged to the left front wheel frame 3, and the piston rod of the left front hydraulic cylinder 12 is connected to the second link 29; the left rear link mechanism includes a third link 30 and a fourth link 31, the first end of the third link 30 is hinged to the left frame 2, the second end of the third link 30 is hinged to the first end of the fourth link 31, the second end of the fourth link 31 is hinged to the left rear wheel frame 4, the piston rod of the left rear hydraulic cylinder 13 is connected to the fourth link Rod 31 is connected; the right front connecting rod mechanism includes a fifth connecting rod 32 and a sixth connecting rod 33, the first end of the fifth connecting rod 32 is hinged to the right frame 7, the second end of the fifth connecting rod 32 is hinged to the first end of the sixth connecting rod 33, the second end of the sixth connecting rod 33 is hinged to the right front wheel frame 8, and the piston rod of the right front hydraulic cylinder 14 is connected to the sixth connecting rod 33; the right rear connecting rod mechanism includes a seventh connecting rod 34 and an eighth connecting rod 35, the first end of the seventh connecting rod 34 is hinged to the right frame 7, the second end of the seventh connecting rod 34 is hinged to the first end of the eighth connecting rod 35, the second end of the eighth connecting rod 35 is hinged to the right rear wheel frame 9, and the piston rod of the right rear hydraulic cylinder 15 is connected to the eighth connecting rod 35.

[0056] The left traveling mechanism and the right traveling mechanism as a whole form a left-right symmetrical structure with respect to the main frame 1. The left front hydraulic cylinder 12, the left rear hydraulic cylinder 13, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 have completely consistent sizes. The corresponding connecting rods on the traveling mechanisms on the same side have consistent sizes. The corresponding connecting rods that are symmetrical on the left and right have consistent sizes. For example, the first connecting rod 28 and the third connecting rod 30 have consistent sizes, the first connecting rod 28 and the fifth connecting rod 32 have consistent sizes, and so on.

[0057] According to another embodiment of the present application, the left front link mechanism, the left rear link mechanism, the right front link mechanism and the right rear link mechanism are all planar six-link mechanisms.

[0058] According to one embodiment of the present application, the left front wheel frame 3 is rotatably connected to the left frame 2 via a first swivel support 36, the left rear wheel frame 4 is rotatably connected to the left frame 2 via a second swivel support 37, the right front wheel frame 8 is rotatably connected to the right frame 7 via a third swivel support 38, and the right rear wheel frame 9 is rotatably connected to the right frame 7 via a fourth swivel support 39.

[0059] Specifically, the first slewing support 36 and the second slewing support 37 each include a fixed circle fixedly connected to the left frame 2 and a rotating circle rotatably connected to the corresponding fixed circle, the third slewing support 38 and the fourth slewing support 39 each include a fixed circle fixedly connected to the right frame 7 and a rotating circle rotatably connected to the corresponding fixed circle, the first mechanical synchronization mechanism 200 is a first inverse quadrilateral connecting rod synchronization mechanism or a first chain 201 synchronization mechanism that is transmission-connected to the rotating circle of the first slewing support 36 and the rotating circle of the second slewing support 37, and the second mechanical synchronization mechanism 300 is a second inverse quadrilateral connecting rod synchronization mechanism or a second chain 202 synchronization mechanism that is transmission-connected to the rotating circle of the third slewing support 38 and the rotating circle of the fourth slewing support 39.

[0060] See also Figure 4 , Figure 5 , Figures 7 to 9 According to one embodiment of the present application, the all-wheel steering system includes a turning angle detection device 23 (for example, an angle detection sensor) for detecting the left front wheel 5, the left rear wheel 6, the right front wheel 10 and the right rear wheel 11, and the steering hydraulic system also includes an intermediate oil circuit 24, a first electrically controlled on-off valve 25, a second electrically controlled on-off valve 26 and a third electrically controlled on-off valve 27. The first electrically controlled on-off valve 25, the second electrically controlled on-off valve 26 and the third electrically controlled on-off valve 27 are, for example, in the form of solenoid valves, wherein the first electrically controlled on-off valve 25 is turned on when de-energized and turned off when energized, the second electrically controlled on-off valve 26 is turned off when de-energized and turned on when energized, the third electrically controlled on-off valve 27 is turned on when de-energized and turned off when energized, one end of the intermediate oil circuit 24 is connected to a first connection point of the series oil circuit 18, and the other end of the intermediate oil circuit 24 is connected to a second connection point of the second main oil circuit 17, and the first electrically controlled on-off valve 25 is arranged on the series oil circuit 18 and is located at the first connection point of the second main oil circuit 17. Between the first connection point and the fourth connection oil circuit 22, the second electrically controlled on-off valve 26 is arranged on the intermediate oil circuit 24, the third electrically controlled on-off valve 27 is arranged on the second main oil circuit 17 and is located between the second connection point and the third connection oil circuit 21, the angle detection device 23 is signal-connected with the first electrically controlled on-off valve 25, the second electrically controlled on-off valve 26 and the third electrically controlled on-off valve 27, the angle detection device 23 can be installed on the corresponding wheel frame or the rotating circle of the slewing support, for example, one angle detection device 23 is installed on each of the rotating circles of the first slewing support 36, the second slewing support 37, the third slewing support 38 and the fourth slewing support 39, for detecting the angles of the left rear wheel 6 and the right rear wheel 11, the function of the angle detection device 23 is mainly to assist detection, and is only used for debugging and adjusting the initial value of the wheel angle on both sides in case of leakage.

[0061] In this embodiment, the angle detection device 23 is used to calibrate the hydraulic cylinder to the end. If one end of the hydraulic cylinder is extended to the end, and the other end is not retracted to the end, the first electrically controlled on-off valve 25, the second electrically controlled on-off valve 26 and the third electrically controlled on-off valve 27 are started to compensate for the angle error. Specifically, since the left front hydraulic cylinder 12, the left rear hydraulic cylinder 13, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 may leak, a difference will form between the left and right sides over time. At this time, calibration is required. After starting the calibration, turn the steering wheel to the left. At this time, the piston rods of the left front hydraulic cylinder 12 and the left rear hydraulic cylinder 13 will retract, and the piston rods of the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 will extend. The following two situations can be referred to for details:

[0062] 1. See Figure 8 , the piston rods of the left front hydraulic cylinder 12 and the left rear hydraulic cylinder 13 have not retracted into place, and the piston rods of the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 have extended into place. The angle detection device 23 detects this situation and transmits a signal to the controller. The controller controls the first electrically controlled on-off valve 25, the second electrically controlled on-off valve 26 and the third electrically controlled on-off valve 27 to be energized. At this time, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 are shielded, and the oil drives the piston rods of the left front hydraulic cylinder 12 and the left rear hydraulic cylinder 13 to retract into the bottom.

[0063] 2. See Fig. 9 The piston rods of the left front hydraulic cylinder 12 and the left rear hydraulic cylinder 13 are retracted into place, while the piston rods of the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 are not extended into place. The angle detection device 23 detects this situation and transmits a signal to the controller. The controller controls the second electrically controlled on-off valve 26 to be energized, while the first electrically controlled on-off valve 25 and the third electrically controlled on-off valve 27 are still in a de-energized state. At this time, the right front hydraulic cylinder 14 and the right rear hydraulic cylinder 15 form a differential cylinder, and their piston rods can still be extended into place.

[0064] According to one embodiment of the present application, the movable circle of the first rotary support 36 is connected to the first sprocket 40, the movable circle of the second rotary support 37 is connected to the second sprocket 41, the movable circle of the third rotary support 38 is connected to the third sprocket 42, the movable circle of the fourth rotary support 39 is connected to the fourth sprocket 43, the first mechanical synchronization mechanism 200 is a first chain 201 synchronization mechanism, and the second mechanical synchronization mechanism 300 is a second chain 202 synchronization mechanism;

[0065] The first mechanical synchronization mechanism 200 includes a first chain 201, a second chain 202, a first pull plate 203 and a second pull plate 204, the first pull plate 203 and the second pull plate 204 are arranged crosswise with each other, the first end of each of the first pull plate 203 and the second pull plate 204 faces the front end of the left frame 2, and the second end of each of the first pull plate 203 and the second pull plate 204 faces the rear end of the left frame 2, the first chain 201 is meshed with the first sprocket 40, and the two ends of the first chain 201 are respectively connected to the first ends of the first pull plate 203 and the second pull plate 204, the second chain 202 is meshed with the second sprocket 41, and the two ends of the second chain 202 are respectively connected to the second ends of the first pull plate 203 and the second pull plate 204;

[0066] The second mechanical synchronization mechanism 300 includes a third chain 301, a fourth chain 302, a third pull plate 303 and a fourth pull plate 304, the third pull plate 303 and the fourth pull plate 304 are arranged crosswise with each other, the first end of the third pull plate 303 and the fourth pull plate 304 are respectively facing the front end of the right frame 7, and the second end of the third pull plate 303 and the fourth pull plate 304 are respectively facing the rear end of the right frame 7, the third chain 301 is engaged with the third sprocket 42 and the two ends of the third chain 301 are respectively connected to the first ends of the third pull plate 303 and the fourth pull plate 304, the fourth chain 302 is engaged with the fourth sprocket 43 and the two ends of the fourth chain 302 are respectively connected to the second ends of the third pull plate 303 and the fourth pull plate 304.

[0067] In addition, the present invention also provides a straddle carrier, wherein the straddle carrier comprises the above-mentioned all-wheel steering system. Fig.10 FIG. 1 is a schematic diagram of the steering of each wheel of a straddle carrier according to an embodiment of the present invention. The steering angle accuracy of the whole vehicle during steering is precisely designed by the position of the mechanical connection points (such as the connecting rod hinge points, etc.) to ensure that the steering angle relationship between the left wheel and the right wheel satisfies the Ackerman theorem and the steering error is controlled within an acceptable range. Specifically, the steering angle of each wheel must comply with the Ackerman's law, which means that the inner and outer steering angles satisfy the formula (cotβ-cotα=K / L) to achieve a full-wheel rolling state.

[0068] It should be noted that the above embodiments only express the preferred implementation of the present application, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the present application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, such as combining different features in various embodiments, etc., which should all fall within the scope of protection of the present application.

Claims

1. An all-wheel steering system, characterized in that: The all-wheel steering system comprises: Main frame, left travel mechanism and right travel mechanism; The left traveling mechanism comprises a left frame, a left front wheel frame, a left rear wheel frame, a left front wheel and a left rear wheel, wherein the left frame is connected to the left side of the main frame, the left front wheel frame is rotatably connected to the front end of the left frame, the left front wheel is mounted on the left front wheel frame, the left rear wheel frame is rotatably connected to the rear end of the left frame, and the left rear wheel is mounted on the left rear wheel frame; The right traveling mechanism comprises a right frame, a right front wheel frame, a right rear wheel frame, a right front wheel and a right rear wheel, wherein the right frame is connected to the right side of the main frame, the right front wheel frame is rotatably connected to the front end of the right frame, the right front wheel is mounted on the right front wheel frame, the right rear wheel frame is rotatably connected to the rear end of the right frame, and the right rear wheel is mounted on the right rear wheel frame; A steering hydraulic system comprises a hydraulic steering gear and a left front hydraulic cylinder, a left rear hydraulic cylinder, a right front hydraulic cylinder and a right rear hydraulic cylinder connected to the hydraulic steering gear, wherein the left front hydraulic cylinder is drivingly connected to the left front wheel frame, the left rear hydraulic cylinder is drivingly connected to the left rear wheel frame, the right front hydraulic cylinder is drivingly connected to the right front wheel frame, and the right rear hydraulic cylinder is drivingly connected to the right rear wheel frame, and the hydraulic steering gear is used for oil supply and oil return of the left front hydraulic cylinder, the left rear hydraulic cylinder, the right front hydraulic cylinder and the right rear hydraulic cylinder, so that when the left front hydraulic cylinder, the left rear hydraulic cylinder, the right front hydraulic cylinder and the right rear hydraulic cylinder are telescopically moved, the left front wheel frame and the right front wheel frame can be driven to rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left rear wheel frame and the right rear wheel frame can rotate synchronously in the same direction with unequal angles under the premise of satisfying the Ackerman formula, the left front wheel frame and the left rear wheel frame rotate synchronously in opposite directions with the same angle, and the right front wheel frame and the right rear wheel frame rotate synchronously in opposite directions with the same angle; a first mechanical synchronization mechanism and a second mechanical synchronization mechanism, wherein the first mechanical synchronization mechanism is respectively connected to the left front wheel frame and the left rear wheel frame in a transmission manner so as to enable the left front wheel frame and the left rear wheel frame to rotate synchronously in opposite directions and at the same angle; and the second mechanical synchronization mechanism is respectively connected to the right front wheel frame and the right rear wheel frame in a transmission manner so as to enable the right front wheel frame and the right rear wheel frame to rotate synchronously in opposite directions and at the same angle; The cylinder body of the left front hydraulic cylinder is hinged to the left frame, the piston rod of the left front hydraulic cylinder is drivingly connected to the left front wheel frame, the cylinder body of the left rear hydraulic cylinder is hinged to the left frame, the piston rod of the left rear hydraulic cylinder is drivingly connected to the left rear wheel frame, the cylinder body of the right front hydraulic cylinder is hinged to the right frame, the piston rod of the right front hydraulic cylinder is drivingly connected to the right front wheel frame, the cylinder body of the right rear hydraulic cylinder is hinged to the right frame, and the piston rod of the right rear hydraulic cylinder is drivingly connected to the right rear wheel frame; The hydraulic steering gear has a first working oil port and a second working oil port, and the steering hydraulic system also includes a first main oil circuit, a second main oil circuit, a series oil circuit, a first connecting oil circuit, a second connecting oil circuit, a third connecting oil circuit and a fourth connecting oil circuit. The rodless chamber of the left front hydraulic cylinder is connected to the rodless chamber of the left rear hydraulic cylinder through the first connecting oil circuit, the rod chamber of the left front hydraulic cylinder is connected to the rod chamber of the left rear hydraulic cylinder through the second connecting oil circuit, the rodless chamber of the right front hydraulic cylinder is connected to the rodless chamber of the right rear hydraulic cylinder through the third connecting oil circuit, and the rod chamber of the right front hydraulic cylinder is connected to the rod chamber of the right rear hydraulic cylinder through the fourth connecting oil circuit. One end of the first main oil circuit is connected to the first working oil port, the other end of the first main oil circuit is connected to the first connecting oil circuit, one end of the second main oil circuit is connected to the second working oil port, the other end of the second main oil circuit is connected to the third connecting oil circuit, one end of the series oil circuit is connected to the second connecting oil circuit, the other end of the series oil circuit is connected to the fourth connecting oil circuit, when the first working oil port serves as the oil supply port of the first main oil circuit, the second working oil port serves as the oil return port of the second main oil circuit, when the second working oil port serves as the oil supply port of the second main oil circuit, the first working oil port serves as the oil return port of the first main oil circuit; The all-wheel steering system includes a turning angle detection device for detecting the left front wheel, the left rear wheel, the right front wheel and the right rear wheel. The steering hydraulic system also includes an intermediate oil circuit, a first electrically controlled on-off valve, a second electrically controlled on-off valve and a third electrically controlled on-off valve. One end of the intermediate oil circuit is connected to the first connection point of the series oil circuit, and the other end of the intermediate oil circuit is connected to the second connection point of the second main oil circuit. The first electrically controlled on-off valve is arranged on the series oil circuit and is located between the first connection point and the fourth connection oil circuit. The second electrically controlled on-off valve is arranged on the intermediate oil circuit. The third electrically controlled on-off valve is arranged on the second main oil circuit and is located between the second connection point and the third connection oil circuit. The turning angle detection device is signal-connected to the first electrically controlled on-off valve, the second electrically controlled on-off valve and the third electrically controlled on-off valve.

2. The all-wheel steering system according to claim 1, characterized in that: The left travel mechanism also includes a left front link mechanism and a left rear link mechanism connected to the left frame, the piston rod of the left front hydraulic cylinder is connected to the left front link mechanism, the left front link mechanism is connected to the left front wheel frame, the piston rod of the left rear hydraulic cylinder is connected to the left rear link mechanism, and the left rear link mechanism is connected to the left rear wheel frame; The right travel mechanism also includes a right front connecting rod mechanism and a right rear connecting rod mechanism connected to the right frame, the piston rod of the right front hydraulic cylinder is connected to the right front connecting rod mechanism, the right front connecting rod mechanism is connected to the right front wheel frame, the piston rod of the right rear hydraulic cylinder is connected to the right rear connecting rod mechanism, and the right rear connecting rod mechanism is connected to the right rear wheel frame.

3. The all-wheel steering system according to claim 2, characterized in that: The left front link mechanism includes a first link and a second link, the first end of the first link is hinged to the left frame, the second end of the first link is hinged to the first end of the second link, the second end of the second link is hinged to the left front wheel frame, and the piston rod of the left front hydraulic cylinder is connected to the second link; the left rear link mechanism includes a third link and a fourth link, the first end of the third link is hinged to the left frame, the second end of the third link is hinged to the first end of the fourth link, the second end of the fourth link is hinged to the left rear wheel frame, and the piston rod of the left rear hydraulic cylinder is connected to the fourth link; The right front connecting rod mechanism includes a fifth connecting rod and a sixth connecting rod, the first end of the fifth connecting rod is hinged to the right frame, the second end of the fifth connecting rod is hinged to the first end of the sixth connecting rod, the second end of the sixth connecting rod is hinged to the right front wheel frame, and the piston rod of the right front hydraulic cylinder is connected to the sixth connecting rod; the right rear connecting rod mechanism includes a seventh connecting rod and an eighth connecting rod, the first end of the seventh connecting rod is hinged to the right frame, the second end of the seventh connecting rod is hinged to the first end of the eighth connecting rod, the second end of the eighth connecting rod is hinged to the right rear wheel frame, and the piston rod of the right rear hydraulic cylinder is connected to the eighth connecting rod.

4. The all-wheel steering system according to claim 2, characterized in that: The left front link mechanism, the left rear link mechanism, the right front link mechanism and the right rear link mechanism are all planar six-link mechanisms.

5. The all-wheel steering system according to claim 1, characterized in that: The left front wheel frame is rotatably connected to the left frame via a first swivel support, the left rear wheel frame is rotatably connected to the left frame via a second swivel support, the right front wheel frame is rotatably connected to the right frame via a third swivel support, and the right rear wheel frame is rotatably connected to the right frame via a fourth swivel support.

6. The all-wheel steering system according to claim 5, characterized in that: The first and second slewing supports each include a fixed ring fixedly connected to the left frame and a rotating ring rotatably connected to the corresponding fixed ring; the third and fourth slewing supports each include a fixed ring fixedly connected to the right frame and a rotating ring rotatably connected to the corresponding fixed ring; the first mechanical synchronization mechanism is a first inverse quadrilateral connecting rod synchronization mechanism or a first chain synchronization mechanism that is transmission-connected to the rotating ring of the first slewing support and the rotating ring of the second slewing support; the second mechanical synchronization mechanism is a second inverse quadrilateral connecting rod synchronization mechanism or a second chain synchronization mechanism that is transmission-connected to the rotating ring of the third slewing support and the rotating ring of the fourth slewing support.

7. The all-wheel steering system according to claim 6, characterized in that: The movable circle of the first rotary support is connected to a first sprocket, the movable circle of the second rotary support is connected to a second sprocket, the movable circle of the third rotary support is connected to a third sprocket, the movable circle of the fourth rotary support is connected to a fourth sprocket, the first mechanical synchronization mechanism is a first chain synchronization mechanism, and the second mechanical synchronization mechanism is a second chain synchronization mechanism; The first mechanical synchronization mechanism comprises a first chain, a second chain, a first pull plate and a second pull plate, the first pull plate and the second pull plate are arranged crosswise with each other, the first ends of the first pull plate and the second pull plate are respectively oriented toward the front end of the left frame, and the second ends of the first pull plate and the second pull plate are respectively oriented toward the rear end of the left frame, the first chain is meshed with the first sprocket and the two ends of the first chain are respectively connected to the first ends of the first pull plate and the second pull plate, the second chain is meshed with the second sprocket and the two ends of the second chain are respectively connected to the second ends of the first pull plate and the second pull plate; The second mechanical synchronization mechanism includes a third chain, a fourth chain, a third pull plate and a fourth pull plate, the third pull plate and the fourth pull plate are arranged crosswise with each other, the first end of each of the third pull plate and the fourth pull plate faces the front end of the right frame, and the second end of each of the third pull plate and the fourth pull plate faces the rear end of the right frame, the third chain is engaged with the third sprocket and the two ends of the third chain are respectively connected to the first ends of the third pull plate and the fourth pull plate, the fourth chain is engaged with the fourth sprocket and the two ends of the fourth chain are respectively connected to the second ends of the third pull plate and the fourth pull plate.

8. A straddle carrier, characterized in that: The straddle carrier comprises an all-wheel steering system according to any one of claims 1 to 7.

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