A dual-circuit steering hydraulic system for vehicles

Abstract

The present invention relates to the field of vehicle steering systems, and in particular to a dual-circuit steering hydraulic system for vehicles, which can improve the steering assist when heavy vehicles are steering, making the steering of vehicles more labor-saving. A dual-circuit steering hydraulic system for vehicles includes a dual-circuit steering gear, a first power-boosting pump, a first oil tank, a first power-boosting cylinder, a second power-boosting pump, a second oil tank and a second power-boosting cylinder. The first power-boosting pump, the first oil tank and the first power-boosting cylinder are connected to form a first circuit, and the second power-boosting pump, the second oil tank and the second power-boosting cylinder are connected to form a second circuit. The dual-circuit steering gear is connected between the first power-boosting pump and the first power-boosting cylinder, and between the second power-boosting pump and the second power-boosting cylinder. By driving different power-boosting cylinders respectively through two hydraulic circuits, the steering axle is assisted respectively, and the steering power of the steering axle can be increased. Using a dual-circuit steering system can control two steering hydraulic circuits at the same time, and the complexity of the operation remains unchanged.

Description

Technical Field

[0001] The present invention relates to the field of vehicle steering systems, and in particular to a vehicle dual-circuit steering hydraulic system. Background Art

[0002] In the existing ordinary trucks, the power steering system is generally used, which is mainly composed of a steering gear and a hydraulic power-assisting device. The steering gear rotation angle is controlled by the steering wheel, and the hydraulic power-assisting device driven by the engine provides high-pressure hydraulic oil for the steering gear. Therefore, the driver only needs to apply a small torque on the steering wheel to control the steering gear to rotate to an ideal angle, and drive the steering rod system to swing back and forth through the steering rocker arm to drive the steering axle to rotate to achieve the steering of the vehicle. This type of steering method is relatively simple, easy to operate, and reliable. Therefore, the current mainstream truck steering system adopts this arrangement. However, for heavy-duty trucks, the torque output by the steering gear alone or the output torque of the steering gear plus a power-assisting oil cylinder is still less than the resistance torque caused by the vehicle's load, resulting in the vehicle steering being too heavy. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a dual-circuit steering hydraulic system for a vehicle, which can improve the steering assist during steering of a heavy vehicle and make vehicle steering more labor-saving.

[0004] The present invention provides the following solutions:

[0005] A dual-circuit steering hydraulic system for a vehicle includes a dual-circuit steering gear, a first power-boosting pump, a first oil tank, a first power-boosting cylinder, a second power-boosting pump, a second oil tank and a second power-boosting cylinder. The first power-boosting pump, the first oil tank and the first power-boosting cylinder are connected to form a first circuit, and the second power-boosting pump, the second oil tank and the second power-boosting cylinder are connected to form a second circuit. The dual-circuit steering gear is connected between the first power-boosting pump and the first power-boosting cylinder, and between the second power-boosting pump and the second power-boosting cylinder. The dual-circuit steering gear, the first oil tank and the second oil tank are fixedly mounted on a vehicle frame, and the first power-boosting cylinder and the second power-boosting cylinder are mounted on different steering axles. By driving different power-boosting cylinders respectively through two hydraulic circuits to assist the steering axle respectively, the steering power of the steering axle can be increased. Using a dual-circuit steering system can control two steering hydraulic circuits at the same time, and the complexity of the operation remains unchanged.

[0006] Preferably, the dual-circuit steering gear includes a first control valve and a second control valve, wherein the first control valve is connected to the first booster pump, the first oil tank and the two ends of the first booster cylinder, and the second control valve is connected to the second booster pump, the second oil tank and the two ends of the second booster cylinder. The two control valves act simultaneously and independently to control the two hydraulic circuits respectively, without affecting each other.

[0007] Preferably, the dual-circuit steering gear includes an input shaft, and the first control valve and the second control valve are both rotary valves, which are mounted on the input shaft. The input shaft is connected to the steering wheel. When the steering wheel is turned, the torsion bar in the input shaft is elastically deformed, so that there is a relative angular displacement between the valve core and the valve sleeve, and the rotary valve is opened; when the steering wheel is stationary, the rotary valve is closed. The opening and closing of the two hydraulic systems can be controlled simultaneously by the driver turning the steering wheel, and the control method is mechanical, with reliable structure and rapid response.

[0008] Preferably, the dual-circuit steering gear comprises a gear sector and a gear block meshing with each other, the gear sector is fixedly connected to the output shaft, and the gear block is slidably arranged in the dual-circuit steering gear and is threadedly connected to the input shaft. The rotation of the input shaft drives the gear block to move through the threaded transmission mode, and the gear sector is driven to rotate, and the output shaft is connected to the steering column to realize the steering of the vehicle. A ball can also be arranged between the input shaft and the gear block to form a ball screw transmission, and the steering column drive form belongs to a recirculating ball steering gear.

[0009] Preferably, the interior of the dual-circuit steering gear is divided into two chambers by the gear block, and the two chambers are respectively connected to the two ends of the first power-assisting oil cylinder, and the two chambers are respectively connected to different outlets of the first control valve. The two chambers are not connected to each other in the dual-circuit steering gear, and the gear block can be pushed by the difference in oil pressure in the two chambers to move in the form of a piston, so that the hydraulic oil can not only directly act on the power-assisting oil cylinder to assist the steering axle, but also assist the rotation of the steering column, making it easier for the operator to turn the steering wheel.

[0010] Preferably, the input shaft is a hollow structure, and the first oil tank is connected to the first control valve through the hollow part of the input shaft. The hollow setting of the input shaft is used as an oil circuit, which saves the pipeline in the dual-circuit steering gear, makes the chambers on both sides of the gear block more independent, and is not easy to be connected due to the gap between other parts.

[0011] Preferably, the two ends of the second booster oil cylinder are respectively connected to a steering limit valve, which is used to balance the oil pressure in the system and adjust the pressure relief point of the second booster oil cylinder moving toward the two ends.

[0012] Preferably, the first booster pump and the second booster pump are both connected to the vehicle air compressor power. The power of the first booster pump and the second booster pump is provided by the vehicle engine.

[0013] The present invention has the following beneficial effects:

[0014] 1. The present invention uses a dual hydraulic circuit and two power-assisting oil cylinders to assist the vehicle steering, which has a better power-assisting effect;

[0015] 2. Use the input shaft to control the steering column and two hydraulic circuits at the same time, which is easy to operate;

[0016] 3. In addition to directly providing power to the steering axle, the hydraulic circuit also provides power to the rotation of the steering column, making it easier for the driver to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 It is a schematic diagram of the principle of the present invention;

[0020] Figure 3 is a schematic diagram of a first state of a first control valve;

[0021] Figure 4 is a schematic diagram of the second state of the first control valve;

[0022] Figure 5 This is a schematic diagram of the installation of the present invention;

[0023] In the figure, 1-dual-circuit steering gear, 2-first power-assisting pump, 3-first oil tank, 4-first power-assisting cylinder, 5-second power-assisting pump, 6-second oil tank, 7-second power-assisting cylinder, 8-input shaft, 9-frame, 11-first control valve, 12-second control valve, 13-gear block, 14-gear fan, 15-first chamber, 16-second chamber, 17-valve body, 18-valve core, 19-steering limit valve. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] like Figure 1 , Figure 2 , Figure 5As shown, in this embodiment, a dual-circuit steering hydraulic system for a vehicle is provided, including a dual-circuit steering gear 1, a first booster pump 2, a first oil tank 3, a first booster cylinder 4, a second booster pump 5, a second oil tank 6 and a second booster cylinder 7. The first booster pump 2, the first oil tank 3 and the first booster cylinder 4 are connected to form a first circuit, and the second booster pump 5, the second oil tank 6 and the second booster cylinder 7 are connected to form a second circuit. The dual-circuit steering gear 1 is connected between the first booster pump 2 and the first booster cylinder 4, and between the second booster pump 5 and the second booster cylinder 7. The dual-circuit steering gear 1, the first oil tank 3 and the second oil tank 6 are fixedly mounted on a vehicle frame 9, and the first booster cylinder 4 and the second booster cylinder 7 are mounted on different steering axles. The first booster pump 2 and the second booster pump 5 are both connected to the vehicle air compressor through a spline.

[0026] The dual-circuit steering gear 1 includes a first control valve 11 and a second control valve 12. The first control valve 11 connects the first booster pump 2, the first oil tank 3 and the two ends of the first booster cylinder 4. The second control valve 12 connects the second booster pump 5, the second oil tank 6 and the two ends of the second booster cylinder 7. The dual-circuit steering gear 1 also includes an input shaft 8. The first control valve 11 and the second control valve 12 are both rotary valves. The first control valve 11 and the second control valve 12 are installed on the input shaft 8.

[0027] The dual-circuit steering gear 1 includes a gear sector 13 and a gear block 14 meshing with each other, the gear sector 13 is integrated with the output shaft, and the gear block 14 is slidably disposed in the dual-circuit steering gear 1 and is threadedly connected to the input shaft 8. The interior of the dual-circuit steering gear 1 is divided into a first chamber 15 and a second chamber 16 by the gear block 14, the first chamber 15 and the second chamber 16 are respectively connected to the two ends of the first power-assisted oil cylinder 4, and the two chambers are respectively connected to different outlets of the first control valve 11.

[0028] The input shaft 8 is a hollow structure, and the first oil tank 3 is connected to the first control valve 11 through the hollow part of the input shaft 8 .

[0029] Both ends of the second power-assisting oil cylinder 7 are connected to the steering limit valve 19 respectively.

[0030] The working principle of the present invention is as follows:

[0031] like Figure 3 As shown, when the driver turns the steering wheel to the right to drive the input shaft 8 to rotate, the torsion bar in the input shaft deforms to cause the valve core of the first control valve 11 to rotate relative to the valve body to Figure 3The position shown is the first state, which completely isolates the pressure oil pipe from the oil return pipe. The high-pressure oil output by the first booster pump 2 enters the left end of the first booster oil cylinder 4. The right end of the first booster oil cylinder 4 is connected to the oil return pipe. The oil pressure at the left end is higher than that at the right end, pushing the piston of the first booster oil cylinder 4 to the right to provide assistance for vehicle steering. At the same time, the oil pressure in the first chamber 15 in the dual-circuit steering gear 1 is greater than the oil pressure in the second chamber 16, providing pressure for the gear block 13 to move to the right and providing assistance for the rotation of the output shaft. The pressure on the gear block 13 of the input shaft 8 itself can provide a component force for the rotation of the input shaft 8, making it easier for the driver to turn the steering wheel.

[0032] like Figure 4 As shown, when the driver turns the steering wheel to the left to drive the input shaft 8 to rotate, the torsion bar in the input shaft deforms to cause the valve core of the first control valve 11 to rotate relative to the valve body to Figure 4 The position shown is the second state, which completely isolates the pressure oil pipe from the oil return pipe. The high-pressure oil output by the first booster pump 2 enters the right end of the first booster cylinder 4. The left end of the first booster cylinder 4 is connected to the oil return pipe. The oil pressure at the right end is higher than that at the left end, pushing the piston of the first booster cylinder 4 to the left. The force on the first booster cylinder 4 and the gear block 13 is opposite to that in the first state, providing assistance for the vehicle to turn in the other direction.

[0033] The second control valve 12 also controls the high-pressure oil output by the second booster pump 5 to enter different ends of the second booster cylinder 7 by rotating the input shaft 8 in different directions, thereby providing steering assistance.

[0034] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A dual-circuit steering hydraulic system for a vehicle, characterized in that: The vehicle comprises a dual-circuit steering gear, a first power-boosting pump, a first oil tank, a first power-boosting cylinder, a second power-boosting pump, a second oil tank and a second power-boosting cylinder. The first power-boosting pump, the first oil tank and the first power-boosting cylinder are connected to form a first circuit. The second power-boosting pump, the second oil tank and the second power-boosting cylinder are connected to form a second circuit. The dual-circuit steering gear is connected between the first power-boosting pump and the first power-boosting cylinder, and between the second power-boosting pump and the second power-boosting cylinder. The dual-circuit steering gear, the first oil tank and the second oil tank are fixedly mounted on the vehicle frame. The first power-boosting cylinder and the second power-boosting cylinder are mounted on different steering axles. The dual-circuit steering gear comprises a first control valve and a second control valve. The first control valve connects the first power-boosting pump, the first oil tank and the second control valve. The first control valve is connected to the two ends of a power-boosting oil cylinder, the second control valve is connected to the second power-boosting pump, the second oil tank and the two ends of the second power-boosting oil cylinder, the dual-circuit steering gear includes an input shaft, the first control valve and the second control valve are both rotary valves, the first control valve and the second control valve are installed on the input shaft, the dual-circuit steering gear includes a gear sector and a gear block that mesh with each other, the gear sector is fixedly connected to the output shaft, the gear block is slidably arranged in the dual-circuit steering gear and is threadedly connected to the input shaft, the interior of the dual-circuit steering gear is divided into two chambers by the gear block, the two chambers are respectively connected to the two ends of the first power-boosting oil cylinder, and the two chambers are respectively connected to different outlets of the first control valve, and the two ends of the second power-boosting oil cylinder are respectively connected to the steering limit valve.

2. A dual-circuit steering hydraulic system for a vehicle according to claim 1, characterized in that: The input shaft is a hollow structure, and the first oil tank is connected to the first control valve through the hollow part of the input shaft.

3. A dual-circuit steering hydraulic system for a vehicle according to claim 1, characterized in that: The first booster pump and the second booster pump are both connected to the vehicle air compressor power.

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