Power steering systems and engineering vehicles

Abstract

This application relates to the field of engineering vehicle technology, and discloses a power steering system and an engineering vehicle, including a piston cylinder, a main steering pump, an auxiliary steering pump, and a first directional valve. The piston cylinder is used for extension and retraction to drive the axle rotation. The main steering pump is used to drive the piston cylinder for extension and retraction. The auxiliary steering pump is used to drive the piston cylinder for extension and retraction. The first directional valve has at least a first valve position and a second valve position. Under normal load, the first directional valve switches to the second valve position, and the main steering pump provides high-pressure oil to drive the piston cylinder for extension and retraction, thereby driving the axle rotation to achieve power steering. Under higher load, the first directional valve is switched to the first valve position, and the auxiliary steering pump provides an additional flow of high-pressure oil, so that the main steering pump and the auxiliary steering pump jointly provide high-pressure oil to drive the piston cylinder for extension and retraction, so that the piston cylinder can drive the axle rotation to achieve power steering under higher load. In this way, there is no need for the main steering pump to provide a high flow of high-pressure oil, avoiding flow waste of the main steering pump under normal load.

Description

Technical Field

[0001] This application relates to the field of engineering vehicle technology, specifically to a power steering system and an engineering vehicle. Background Technology

[0002] Existing vehicles are often equipped with power steering systems to provide external force to assist steering, helping the driver to complete the turn and reducing the burden on the driver when operating the steering wheel. In particular, some engineering vehicles often have heavy loads, which makes it more difficult for them to turn compared to passenger vehicles, and they rely more on power steering systems for assisted steering.

[0003] The existing steering system of engineering vehicles includes a main steering pump and a steering cylinder. When the steering wheel is turned, the main steering pump drives the steering cylinder to extend and retract, thereby driving the axle to rotate and achieving power steering. Because engineering vehicles may experience special operating conditions with extremely high loads, a high-power main steering pump is needed to provide a large flow rate for the steering cylinder's extension and retraction in order to achieve normal power steering under these conditions. However, in actual use, engineering vehicles mostly operate under normal load conditions, and the extremely high load conditions are not frequent. Under normal operating conditions, a large flow rate is not required, resulting in energy waste.

[0004] Therefore, how to solve or improve the problem of energy waste caused by the large flow rate of the main steering pump under normal operating conditions in related technologies has become an important technical problem to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, this application provides a power steering system and an engineering vehicle to solve or improve the problem of energy waste caused by the large flow rate of the main steering pump under normal operating conditions.

[0006] In a first aspect, this application provides a power steering system, comprising:

[0007] A piston cylinder is used to connect to the axle and to extend and retract to drive the axle to rotate.

[0008] A main steering pump is used to communicate with the piston cylinder and to drive the piston cylinder to extend and retract.

[0009] A secondary steering pump is used to communicate with the piston cylinder and to drive the piston cylinder to extend and retract.

[0010] The first directional valve has at least a first valve position and a second valve position. When the first directional valve is in the first valve position, the auxiliary steering pump can communicate with the piston cylinder through the first directional valve. When the first directional valve is in the second valve position, the auxiliary steering pump is disconnected from the piston cylinder.

[0011] In one alternative implementation, it further includes:

[0012] The first detection element is suitable for detecting the rotation angle of the steering wheel;

[0013] The second detection element is adapted to detect the rotation angle of the axle;

[0014] The processing module is communicatively connected to the first reversing valve, the first detection element, and the second detection element, respectively.

[0015] The processing module is adapted to calculate the theoretical rotation angle of the axle based on the rotation angle of the steering wheel.

[0016] The processing module is also adapted to control the first reversing valve to switch to the first valve position when the rotation angle of the axle is less than the theoretical rotation angle after the steering wheel has been turned and a preset time has elapsed.

[0017] In one alternative implementation, it further includes:

[0018] The oil inlet line is connected to the main steering pump. When the first directional valve is in the first valve position, the auxiliary steering pump can be connected to the oil inlet line through the first directional valve.

[0019] The main directional valve, communicatively connected to the processing module, has at least a third valve position and a fourth valve position. When the main directional valve is in the third valve position, the oil inlet line is connected to the piston cylinder through the main directional valve. When the main directional valve is in the fourth valve position, the oil inlet line is disconnected from the piston cylinder.

[0020] The processing module is adapted to control the main directional valve to switch to the third valve position when the steering wheel is turned.

[0021] In an alternative implementation, the processing module is further adapted to control the main directional valve to switch to the fourth valve position when the rotation angle of the axle is equal to the theoretical rotation angle.

[0022] In one alternative implementation, it further includes:

[0023] The second directional control valve has at least a fifth valve position and a sixth valve position. When the first directional control valve is in the second valve position and the second directional control valve is in the fifth valve position, the auxiliary steering pump is connected to the oil inlet line through the second directional control valve. When the first directional control valve is in the second valve position and the second directional control valve is in the sixth valve position, the auxiliary steering pump is disconnected from the oil inlet line.

[0024] The second reversing valve is connected to the main steering pump. When the main steering pump is working, the second reversing valve switches to the sixth valve position; when the main steering pump stops working, the second reversing valve switches to the fifth valve position.

[0025] In one alternative implementation, it further includes:

[0026] A flow control valve is installed on the oil inlet pipe and is suitable for controlling the flow rate of the oil inlet pipe.

[0027] In one alternative implementation, it further includes:

[0028] A filter is installed on the oil inlet pipe and is adapted to filter the oil flowing through the oil inlet pipe.

[0029] Secondly, this application also provides an engineering vehicle including any of the power steering systems described above.

[0030] In one alternative implementation, it further includes:

[0031] A steering emergency pump, wherein the auxiliary steering pump is configured as the steering emergency pump.

[0032] In one alternative implementation, it further includes:

[0033] The third detection element is suitable for detecting the axle load of the engineering vehicle.

[0034] The processing module is configured such that the third detection element is communicatively connected to the processing module, the auxiliary steering pump is a variable displacement pump and is also communicatively connected to the processing module, and the processing module is adapted to determine the output flow rate of the auxiliary steering pump based on the axle load of the vehicle.

[0035] This application provides a power steering system, including a piston cylinder, a main steering pump, a secondary steering pump, and a first directional control valve. The piston cylinder is connected to the axle, allowing it to drive the axle to rotate during extension and retraction, thus providing power steering assistance. The main steering pump communicates with the piston cylinder and drives its extension and retraction. The secondary steering pump also communicates with the piston cylinder and drives its extension and retraction. The first directional control valve has at least a first valve position and a second valve position, and is switchable between these positions. When the first directional control valve is switched to the first valve position, the secondary steering pump communicates with the piston cylinder through the first directional control valve. When the first directional control valve is switched to the first valve position, the secondary steering pump disconnects the first directional control valve from the piston cylinder.

[0036] With this configuration, under normal load, the first directional valve switches to the second position, disconnecting the auxiliary steering pump from the piston cylinder. The main steering pump connects to the piston cylinder. During steering, the main steering pump provides high-pressure oil to drive the piston cylinder's extension and retraction, thereby rotating the axle to achieve steering assistance. Under higher load, the first directional valve switches to the first position. At this time, both the main and auxiliary steering pumps are connected to the piston cylinder. During steering, the auxiliary steering pump provides an additional flow of high-pressure oil, allowing both the main and auxiliary pumps to jointly provide high-pressure oil to drive the piston cylinder's extension and retraction. This enables the piston cylinder to drive the axle to rotate under higher load, achieving steering assistance. This eliminates the need for the main steering pump to provide a higher flow of high-pressure oil, achieving steering assistance even under higher load, thus avoiding flow waste caused by the main steering pump providing a higher flow of high-pressure oil under normal load. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of this application, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of a power steering system according to an embodiment of this application;

[0039] Figure 2 This is a schematic diagram of the communication connection of the processing module of a power steering system according to an embodiment of this application;

[0040] Figure 3 This is a schematic diagram of the control flow of a power steering system according to an embodiment of this application;

[0041] Figure 4 This is a schematic diagram showing the relationship between the output flow rate of the auxiliary steering pump and the axle rotation angle in an embodiment of this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Piston cylinder; 2. Main steering pump; 3. Auxiliary steering pump; 4. First directional valve; 5. First detection element; 6. Second detection element; 7. Processing module; 8. Oil inlet line; 9. Main directional valve; 10. Second directional valve; 11. Flow control valve; 12. Filter; 13. Third detection element. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] The following is combined Figures 1 to 4 This describes an embodiment of the present application.

[0046] According to embodiments of this application, in one aspect, a power steering system is provided, such as... Figure 1 As shown, the system includes a piston cylinder 1, a main steering pump 2, an auxiliary steering pump 3, and a first directional valve 4. The piston cylinder 1 connects to the axle, allowing it to drive the axle to rotate during extension and retraction, thus providing power steering. The main steering pump 2 communicates with the piston cylinder 1, enabling it to drive the piston cylinder 1 to extend and retract. The auxiliary steering pump 3 also communicates with the piston cylinder 1, driving it to extend and retract.

[0047] The first directional valve 4 has at least a first valve position and a second valve position, and is capable of switching between the first valve position and the second valve position. The first directional valve 4 is disposed between the auxiliary steering pump 3 and the piston cylinder 1. When the first directional valve 4 is switched to the first valve position, the auxiliary steering pump 3 can communicate with the piston cylinder 1 through the first directional valve 4. When the first directional valve 4 is switched to the second valve position, the auxiliary steering pump 3 disconnects the first directional valve 4 from the piston cylinder 1.

[0048] With this configuration, under normal load, the first directional valve 4 switches to the second valve position, disconnecting the auxiliary steering pump 3 from the piston cylinder 1. The main steering pump 2 is connected to the piston cylinder 1. During steering, the main steering pump 2 provides high-pressure oil to drive the piston cylinder 1 to extend and retract, thereby driving the axle to rotate and achieve steering assistance.

[0049] When the load is high, the first directional valve 4 is switched to the first valve position. At this time, both the main steering pump 2 and the auxiliary steering pump 3 are connected to the piston cylinder 1. When steering, the auxiliary steering pump 3 provides high-pressure oil with an additional flow rate, so that the main steering pump 2 and the auxiliary steering pump 3 jointly provide high-pressure oil to drive the piston cylinder 1 to extend and retract, so that when the piston cylinder 1 extends and retracts, it can drive the axle to rotate under high load to achieve steering assistance.

[0050] In this way, since the auxiliary steering pump 3 can provide an additional flow of high-pressure oil, the main steering pump 2 does not need to provide a higher flow of high-pressure oil, and steering assistance can be achieved even under high load, thus avoiding the flow waste caused by the main steering pump 2 providing a higher flow of high-pressure oil under normal load.

[0051] The first directional valve 4 is an electromagnetic directional valve with a first port, a second port, and a third port. The first port is connected to the auxiliary steering pump 3, the second port is connected to the oil tank, and the third port is connected to the piston cylinder 1. When the first directional valve 4 is switched to the first position, the first port and the third port are connected, and the auxiliary steering pump 3 can connect to the piston cylinder 1 through the first directional valve 4. When the first directional valve 4 is switched to the second position, the first port and the second port are connected, and the auxiliary steering pump 3 can connect to the oil tank through the first directional valve 4, while disconnecting from the piston cylinder 1. The high-pressure oil supplied by the auxiliary steering pump 3 is directly discharged from the oil tank.

[0052] As an optional embodiment, such as Figure 1 and Figure 2 As shown, it also includes a first detection element 5, a second detection element 6, and a processing module 7. When the first detection element 5 is installed at the steering wheel, it can detect the rotation angle of the steering wheel in real time. When the second detection element 6 is installed at the axle, it can detect the rotation angle of the axle in real time.

[0053] The processing module 7 is communicatively connected to the first detection element 5, so that the first detection element 5 can send a signal to the processing module 7 after detecting the rotation angle of the steering wheel in real time, enabling the processing module 7 to acquire the rotation angle of the steering wheel in real time. Since the purpose of rotating the steering wheel is to make the axle rotate as intended, the rotation angle of the steering wheel and the theoretical rotation angle of the axle must satisfy a certain ratio. Therefore, the processing module 7 can calculate the theoretical rotation angle of the axle based on the rotation angle of the steering wheel.

[0054] The processing module 7 is communicatively connected to the second detection element 6, so that the second detection element 6 can send a signal to the processing module 7 after detecting the rotation angle of the axle in real time, so that the processing module 7 can obtain the rotation angle of the axle in real time.

[0055] After the steering wheel is turned, the main steering pump 2 provides high-pressure oil to drive the piston cylinder 1 to extend and retract, thereby driving the axle to rotate and achieve steering assistance. Under normal load, after a preset time, the axle should rotate to the theoretical rotation angle.

[0056] Under high load, the amount of high-pressure oil supplied by the main steering pump 2 is insufficient to support the extension and retraction of the piston cylinder 1 to drive the axle rotation. As a result, the axle cannot rotate to the theoretical rotation angle after a preset time, requiring the auxiliary steering pump 3 to provide an additional flow of high-pressure oil.

[0057] Thus, as Figure 3As shown, after a preset time has elapsed after the steering wheel is turned, the processing module 7 obtains the rotation angle of the axle at this time and compares the rotation angle of the axle with the theoretical rotation angle. If the rotation angle of the axle is the same as the theoretical rotation angle, it means that the main steering pump 2 can normally drive the cylinder to extend and retract, thus completing the steering assistance.

[0058] If the axle's rotation angle is less than the theoretical rotation angle, it indicates that the load is too high and the main steering pump 2 alone cannot properly drive the cylinder extension and retraction to complete the steering assistance. At this time, the processing module 7 controls the first reversing valve 4 to switch to the first valve position, so that both the main steering pump 2 and the auxiliary steering pump 3 are connected to the piston cylinder 1. During steering, the auxiliary steering pump 3 provides an additional flow of high-pressure oil, so that the main steering pump 2 and the auxiliary steering pump 3 jointly provide high-pressure oil to drive the piston cylinder 1 to extend and retract, so that the axle's rotation angle reaches the theoretical rotation angle.

[0059] When the rotation angle of the axle is equal to the theoretical rotation angle, the processing module 7 controls the first directional valve 4 to switch to the second valve position.

[0060] This configuration enables the automatic switching of the first directional valve 4, thereby automatically replenishing the flow of the auxiliary directional pump 3, making operation more convenient.

[0061] In optional embodiments, such as Figure 1 and Figure 2 As shown, the power steering system also includes an oil inlet line 8 and a main directional valve 9. The oil inlet line 8 is connected to the main steering pump 2. When the first directional valve 4 is in the first valve position, the auxiliary steering pump 3 can be connected to the oil inlet line 8 through the first directional valve 4, thereby connecting to the piston cylinder 1.

[0062] The main directional valve 9 has at least a third valve position and a fourth valve position, and can switch between the third valve position and the fourth valve position. The main directional valve 9 is located between the oil inlet line 8 and the piston cylinder 1. When the main directional valve 9 is switched to the third valve position, the oil inlet line 8 is connected to the piston cylinder 1 through the main directional valve 9. When the main directional valve 9 is switched to the fourth valve position, the main directional valve 9 disconnects the oil inlet line 8 from the piston cylinder 1.

[0063] The main directional valve 9 is communicatively connected to the processing module 7. When the steering wheel is turned, the processing module 7 can control the main directional valve 9 to switch to the third valve position, so that the oil inlet line 8 is connected to the piston cylinder 1. Then, the high-pressure oil entering the oil inlet line 8 can drive the piston cylinder 1 to extend and retract, thereby driving the axle to rotate.

[0064] This setting, such as Figure 3 As shown, after the steering wheel is turned, the processing module 7 controls the main directional valve 9 to switch to the third valve position, so that the high-pressure oil supplied by the main steering pump 2 to the oil inlet line 8 can flow to the piston cylinder 1 through the main steering pump 2. The processing module 7 calculates the theoretical rotation angle of the axle based on the rotation angle of the steering wheel.

[0065] If the axle rotation angle is the same as the theoretical rotation angle after the preset time, it means that the main steering pump 2 can drive the cylinder extension and retraction normally to complete the steering assistance.

[0066] If the axle's rotation angle is less than the theoretical rotation angle, it indicates that the load is too high and the main steering pump 2 alone cannot properly drive the cylinder extension and retraction to complete the steering assistance. At this time, the processing module 7 controls the first reversing valve 4 to switch to the first valve position, so that both the main steering pump 2 and the auxiliary steering pump 3 are connected to the oil inlet line. During steering, the auxiliary steering pump 3 provides an additional flow of high-pressure oil into the oil outlet line, so that the main steering pump 2 and the auxiliary steering pump 3 jointly provide high-pressure oil to drive the piston cylinder 1 to extend and retract, so that the axle's rotation angle reaches the theoretical rotation angle.

[0067] The main steering valve has a fourth port, a fifth port, a sixth port, and a seventh port. The fourth port is connected to the oil inlet line 8, the fifth port is connected to the oil tank, the sixth port is connected to the rodless chamber of piston cylinder 1, and the seventh port is also connected to the rodless chamber of piston cylinder 1. When the main directional valve 9 switches to the third position, the high-pressure oil entering the oil inlet line 8 can enter piston cylinder 1 through the main steering valve, thereby achieving the extension and retraction of piston cylinder 1.

[0068] When the main directional valve 9 switches to the fourth position, the fourth and fifth oil ports are connected, allowing the high-pressure oil entering the inlet pipe 8 to return directly to the oil tank. The main directional valve 9 then disconnects the inlet pipe 8 from the piston cylinder 1, preventing the high-pressure oil from entering the piston cylinder 1 and thus stopping the power steering. The disconnection of the inlet pipe 8 from the piston cylinder 1 means that the high-pressure oil returns directly to the oil tank without entering the piston cylinder 1.

[0069] Piston cylinder 1 includes a cylinder body, a piston, and a piston rod. The piston is slidably mounted in the cylinder body. One end of the piston rod extends into the cylinder body and connects to the piston, while the other end connects to the axle. Inside the cylinder body, a rod chamber is formed on the side of the piston closest to the piston rod, and a rodless chamber is formed on the side of the piston away from the piston rod. Oil enters the rodless chamber, and when oil exits the rod chamber, the piston rod extends to drive the axle to rotate. When oil enters the rod chamber and exits the rodless chamber, the piston rod retracts to drive the axle to rotate in the opposite direction.

[0070] When the main directional valve 9 is switched to the third position, the fourth oil port is connected to the sixth oil port, and the fifth oil port is connected to the seventh oil port. At this time, the high-pressure oil entering the oil inlet line 8 can enter the rod chamber of the piston cylinder 1 through the main directional valve, and the oil in the rodless chamber of the piston cylinder 1 can return to the oil tank through the main directional valve, thereby realizing the extension of the piston cylinder 1.

[0071] The main directional valve 9 also has a seventh valve position. When the main directional valve 9 is switched to the seventh valve position, the fifth oil port is connected to the sixth oil port, and the fourth oil port is connected to the seventh oil port. At this time, the high-pressure oil entering the oil inlet line 8 can enter the rodless chamber of the piston cylinder 1 through the main directional valve, and the oil in the rod chamber of the piston cylinder 1 can return to the oil tank through the main directional valve, thereby realizing the retraction of the piston cylinder 1.

[0072] In some embodiments, such as Figure 3 As shown, the processing module 7 can also control the main directional valve 9 to switch to the fourth valve position when the rotation angle of the axle is equal to the theoretical rotation angle.

[0073] With this configuration, after the steering wheel is turned, the processing module 7 controls the main directional valve 9 to switch to the third valve position, allowing the high-pressure oil supplied by the main steering pump 2 to the oil inlet line 8 to flow through the main steering pump 2 to the piston cylinder 1. The processing module 7 calculates the theoretical rotation angle of the axle based on the steering wheel rotation angle.

[0074] If the axle rotation angle is the same as the theoretical rotation angle after a preset time, it indicates that the main steering pump 2 can normally drive the hydraulic cylinder to extend and retract, thus completing the steering assist. The processing module 7 controls the main directional valve 9 to switch to the fourth valve position, and the high-pressure oil in the oil inlet line 8 no longer enters the piston cylinder 1, thereby stopping the steering assist.

[0075] If the axle's rotation angle is less than the theoretical rotation angle, the processing module 7 controls the first directional valve 4 to switch to the first valve position, so that the main steering pump 2 and the auxiliary steering pump 3 are both connected to the oil inlet pipe 8. The auxiliary steering pump 3 provides additional flow of high-pressure oil into the oil inlet pipe 8, so that the main steering pump 2 and the auxiliary steering pump 3 jointly provide high-pressure oil to drive the piston cylinder 1 to extend and retract, so that the axle's rotation angle reaches the theoretical rotation angle.

[0076] Once the axle reaches its theoretical rotation angle, the processing module 7 controls the main directional valve 9 to switch to the fourth position, preventing high-pressure oil from the oil inlet line 8 from entering the piston cylinder 1, thus stopping the power steering. Simultaneously, the processing module 7 controls the first directional valve 4 to switch to the second position.

[0077] This configuration allows the main steering pump 2 or the auxiliary steering pump 3 to automatically cancel the input of high-pressure oil to the piston cylinder 1 after the power steering is completed.

[0078] In some embodiments, such as Figure 1 As shown, the power steering system also includes a second directional control valve 10, which has at least a fifth valve position and a sixth valve position. The second directional control valve 10 can switch between the fifth valve position and the sixth valve position. When the second directional control valve 10 is switched to the fifth valve position, the auxiliary steering pump 3 is connected to the oil inlet line 8 through the second directional control valve 10.

[0079] When the first directional valve 4 switches to the second valve position and the second directional valve 10 switches to the sixth valve position, the second directional valve 10 disconnects the auxiliary steering pump 3 from the oil inlet line 8.

[0080] The second directional valve 10 is connected to the main steering pump 2, so that when the main steering pump 2 is working, the second directional valve 10 can be driven to switch to the sixth valve position, and when the main steering pump 2 is not working, the second directional valve 10 switches to the fifth valve position.

[0081] Specifically, a spring is installed on one side of the valve core of the second directional valve 10, and the other side is connected to the main steering pump 2. When the main steering pump 2 is working, high-pressure oil is supplied to push the valve core close to the spring, thereby driving the second directional valve 10 to switch to the sixth valve position. When the main steering pump 2 is not working, the pushing force on the valve core is released, and under the elastic force of the spring, the valve core is pushed to slide, causing the second directional valve 10 to switch to the fifth valve position.

[0082] With this configuration, when the main steering pump 2 is working normally, the second directional valve 10 is in the fifth position and the first directional valve 4 is in the second position. When the main steering pump 2 is insufficient in oil supply, the first directional valve 4 is switched to the first position, allowing the auxiliary steering pump 3 to supplement the flow. When the main steering pump 2 malfunctions, it cannot provide high-pressure oil, causing the second directional valve 10 to switch to the sixth position. At this time, the auxiliary steering pump 3 can replace the piston cylinder 1 of the main steering pump 2 to provide high-pressure oil, preventing a direct loss of steering power and potential vehicle loss of control in the event of a main steering pump 2 malfunction.

[0083] In some embodiments, such as Figure 1 As shown, the power steering system also includes a flow control valve 11, which is installed on the oil inlet line 8. When hydraulic fluid flows through the oil inlet line 8, the flow control valve 11 controls the flow rate of the fluid in the oil inlet line 8. When the flow rate in the oil inlet line 8 exceeds the preset value of the flow control valve 11, the flow control valve 11 can return the excess fluid to the oil tank to ensure that the flow rate in the oil inlet line 8 is controlled within the preset value, thus preventing damage to the piston cylinder 1 due to excessive flow.

[0084] In some embodiments, such as Figure 1 As shown, the power steering system also includes a filter 12, which is installed on the oil inlet line 8. During the flow of oil through the oil inlet line 8, when the oil flows through the filter 12, the filter 12 can filter the oil to prevent impurities in the oil from damaging the piston cylinder 1.

[0085] According to an embodiment of this application, another aspect provides an engineering vehicle including any of the power steering systems described above. The technical effects of this engineering vehicle are the same as those of the power steering system, and therefore will not be repeated.

[0086] As an optional implementation, the engineering vehicle also includes a steering emergency pump. This pump is the core emergency power source for the steering system, providing hydraulic assistance in case of main pump failure or power interruption, ensuring safe vehicle steering. When the main steering pump fails, the engine stalls, or power transmission is interrupted, the steering emergency pump immediately activates, providing hydraulic power to the steering system, preventing the steering wheel from becoming heavy or even locking up, and ensuring vehicle controllability.

[0087] The auxiliary steering pump 3 is configured as a steering emergency pump. That is, the steering emergency pump of the engineering vehicle serves as the auxiliary steering pump 3.

[0088] Under normal conditions, the first directional valve 4 of the emergency steering pump switches to the second valve position, connecting the main steering pump 2 to the piston cylinder 1, while disconnecting the emergency steering pump from the piston cylinder 1. At this time, during steering, the main steering pump 2 provides high-pressure oil to drive the piston cylinder 1 to extend and retract, thereby rotating the axle to achieve steering assistance. The emergency pump then only performs its original function, providing hydraulic assistance when the main steering pump 2 fails.

[0089] When the load is high, the first directional valve 4 is switched to the first valve position. At this time, the main steering pump 2 and the emergency pump are connected to the piston cylinder 1. When steering, the emergency pump provides additional flow of high-pressure oil, so that the main steering pump 2 and the emergency pump jointly provide high-pressure oil to drive the piston cylinder 1 to extend and retract, so that when the piston cylinder 1 extends and retracts, it can drive the axle to rotate under high load to achieve steering assistance.

[0090] In this way, the oil supply capacity of the emergency pump is used to provide steering assistance to the main steering pump 2, eliminating the need for an additional pump body as the auxiliary steering pump 3, thus reducing costs.

[0091] Moreover, since the emergency pump is used intermittently, its function can be checked intermittently, eliminating the need for periodic checks and saving maintenance time.

[0092] As an optional embodiment, such as Figure 2 As shown, the engineering vehicle also includes a third detection element 13 and a processing module 7. The third detection element 13 is installed on the axle of the engineering vehicle and can detect the axle load of the entire vehicle. The axle load of the entire vehicle refers to the vertical load weight borne by each axle when the vehicle is stationary or moving. The third detection element 13 can be a pressure sensor.

[0093] The third detection element 13 is communicatively connected to the processing module 7. The auxiliary steering pump 3 is a variable displacement pump. The processing module 7 is adapted to determine the output flow rate of the auxiliary steering pump 3 based on the vehicle axle load, specifically regarding the output flow rate of the auxiliary steering pump 3.

[0094] For the same rotation angle, the required assist flow rate for piston cylinder 1 varies depending on the axle load. Furthermore, the greater the axle load, the greater the required assist flow rate for piston cylinder 1.

[0095] In this way, the processing module 7 can determine the output flow rate of the auxiliary steering pump 3 based on the axle load of the vehicle, so that the auxiliary steering pump 3 is set to that output flow rate.

[0096] Specifically, such as Figure 4 As shown, the relationship curve between the output flow rate Q of the auxiliary steering pump 3 and the axle rotation angle θ can be determined based on different values ​​of axle load a, axle load b, or axle load c, thus determining the output flow rate of the auxiliary steering pump 3.

[0097] That is, when the axle load is a, the output flow rate Q of the auxiliary steering pump 3 is determined according to the relationship curve corresponding to axle load a and the axle rotation angle θ; when the axle load is b, the output flow rate Q of the auxiliary steering pump 3 is determined according to the relationship curve corresponding to axle load b and the axle rotation angle θ; when the axle load is c, the output flow rate Q of the auxiliary steering pump 3 is determined according to the relationship curve corresponding to axle load c and the axle rotation angle θ.

[0098] Where a, b, and c can be range values.

[0099] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by this application.

Claims

1. A power assisted steering system characterised in that, include: A piston cylinder (1) is used to connect to the axle and to extend and retract to drive the axle to rotate; The main steering pump (2) is used to communicate with the piston cylinder (1) and to drive the piston cylinder (1) to extend and retract; A secondary steering pump (3) is used to communicate with the piston cylinder (1) and to drive the piston cylinder (1) to extend and retract; The first directional valve (4) has at least a first valve position and a second valve position. When the first directional valve (4) is in the first valve position, the auxiliary steering pump (3) can communicate with the piston cylinder (1) through the first directional valve (4). When the first directional valve (4) is in the second valve position, the auxiliary steering pump (3) is disconnected from the piston cylinder (1).

2. A power assisted steering system according to claim 1, characterised in that, Also includes: The first detection element (5) is adapted to detect the rotation angle of the steering wheel; The second detection element (6) is adapted to detect the rotation angle of the axle; The processing module (7) is communicatively connected to the first reversing valve (4), the first detection element (5), and the second detection element (6), respectively. The processing module (7) is adapted to calculate the theoretical rotation angle of the axle based on the rotation angle of the steering wheel. The processing module (7) is also adapted to control the first reversing valve (4) to switch to the first valve position when the rotation angle of the axle is less than the theoretical rotation angle after the steering wheel has been turned and a preset time has elapsed.

3. A power assisted steering system according to claim 2, characterised in that, Also includes: The oil inlet line (8) is connected to the main steering pump (2). When the first reversing valve (4) is in the first valve position, the auxiliary steering pump (3) can be connected to the oil inlet line (8) through the first reversing valve (4). The main directional valve (9) is communicatively connected to the processing module (7) and has at least a third valve position and a fourth valve position. When the main directional valve (9) is in the third valve position, the oil inlet line (8) is connected to the piston cylinder (1) through the main directional valve (9). When the main directional valve (9) is in the fourth valve position, the oil inlet line (8) is disconnected from the piston cylinder (1). The processing module (7) is adapted to control the main directional valve (9) to switch to the third valve position when the steering wheel is turned.

4. A power assisted steering system according to claim 3, characterised in that, The processing module (7) is also adapted to control the main directional valve (9) to switch to the fourth valve position when the rotation angle of the axle is equal to the theoretical rotation angle.

5. The power steering system of claim 3, wherein Also includes: The second directional valve (10) has at least a fifth valve position and a sixth valve position. When the first directional valve (4) is in the second valve position and the second directional valve (10) is in the fifth valve position, the auxiliary steering pump (3) is connected to the oil inlet line (8) through the second directional valve (10). When the first directional valve (4) is in the second valve position and the second directional valve (10) is in the sixth valve position, the auxiliary steering pump (3) is disconnected from the oil inlet line (8). The second reversing valve (10) is connected to the main steering pump (2). When the main steering pump (2) is working, the second reversing valve (10) switches to the sixth valve position; when the main steering pump (2) stops working, the second reversing valve (10) switches to the fifth valve position.

6. The power steering system of claim 3, wherein Also includes: A flow control valve (11) is installed on the oil inlet pipe (8) and is suitable for controlling the flow rate of the oil inlet pipe (8).

7. The power steering system of claim 3, wherein Also includes: A filter (12) is provided on the oil inlet pipe (8) and is suitable for filtering the oil flowing through the oil inlet pipe (8).

8. An engineering vehicle characterized by, Includes the power steering system as described in any one of claims 1-7.

9. The work vehicle of claim 8, characterized by, Also includes: Steering emergency pump, wherein the auxiliary steering pump (3) is configured as the steering emergency pump.

10. The work vehicle of claim 8, characterized in that, Also includes: The third detection element (13) is suitable for detecting the axle load of the engineering vehicle. The processing module (7) is connected in communication with the third detection element (13), the auxiliary steering pump (3) is a variable pump, and the processing module (7) is adapted to determine the output flow rate of the auxiliary steering pump (3) according to the axle load of the vehicle.

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