CN111350227A - Rotary hydraulic system, control method of rotary hydraulic system and excavator - Google Patents

Abstract

The invention relates to the technical field of hydraulic systems, and particularly discloses a rotary hydraulic system, a control method of the rotary hydraulic system and an excavator. When the vehicle is in a half slope and turns from a low position to a high position, the controller controls the first overflow valve to have larger overflow pressure, the first pipeline keeps higher oil pressure, and the rotary motor can output larger torque so as to meet the requirement of the vehicle on the rotary torque at the moment; when the vehicle is in flat ground operation, the controller controls the first overflow valve to have smaller overflow pressure, the first pipeline keeps lower oil pressure, the rotary motor outputs smaller torque, the rotary motor is prevented from being in a high-pressure state for a long time, the abrasion of the rotary motor is reduced, and the service life is prolonged.

Description

Rotary hydraulic system, control method of rotary hydraulic system and excavator

Technical Field

The invention relates to the technical field of hydraulic systems, in particular to a rotary hydraulic system, a control method of the rotary hydraulic system and an excavator.

Background

Among construction machines, there are various types of machines having a swing work capability, and an excavator is the most typical. The excavator has the reputation of the king of engineering machinery, and can operate under various complex working conditions by using multi-mechanism composite action, wherein the rotary operation capability is one of the most important performances of the excavator, and the rotary torque of the excavator directly influences the operation efficiency of the whole excavator.

The excavator is composed of a lower traveling mechanism and an upper body rotatably mounted on the lower traveling mechanism, and the rotation of the upper body is driven by a rotation motor. When the excavator works on the flat ground, the center of gravity of the upper body does not change in height due to the rotation of the upper body, and the center of gravity of the upper body moves in a horizontal plane. At present, the working pressure of a rotary motor of an excavator is a fixed value, and the provided rotary torque can generally meet the requirement of operation on flat ground. However, when the excavator rotates on a half slope, unlike the horizontal ground, if the bucket is heavily loaded or has a large radius of gyration, the excavator is influenced by gravitational potential energy caused by the inclination angle of the body, the moment of gyration required by the upper mechanism is also increased, when the excavator gyrates from a low position to a high position, the shortage of moment of gyration may cause the whole excavator to gyrate slowly or even to be unable to gyrate, and the normal operation requirement cannot be met.

Disclosure of Invention

The invention aims to: the invention provides a rotary hydraulic system, a control method of the rotary hydraulic system and an excavator, and aims to solve the problems that in order to ensure that the rotary hydraulic system can normally rotate on a half slope, the working pressure of a rotary motor is simply improved, the rotary motor is easily in a high-pressure state for a long time, the abrasion in the rotary motor is aggravated, and the service life of the rotary motor is influenced in the excavator in the related art.

In one aspect, the present invention provides a swing hydraulic system, comprising:

the input end of the oil pump is connected with the oil tank;

the rotary motor is used for driving the vehicle body to rotate, and the output end of the oil pump is connected with the rotary motor through a first pipeline;

the first overflow valve is connected with the first pipeline and the oil tank;

and the controller is connected with the first overflow valve and is used for controlling the overflow pressure of the first overflow valve.

The controller can adjust the oil pressure of the first pipeline by controlling the overflow pressure of the first overflow valve, and further realize the adjustment of the driving oil pressure of the rotary motor. When the vehicle is in the semi-slope rotary operation and rotates from a low position to a high position, the controller can control the first overflow valve to have larger overflow pressure, so that the first pipeline can keep higher oil pressure, and the rotary motor can output larger torque to meet the requirement of the vehicle on the rotary torque at the moment; when the vehicle is in flat ground operation, the controller can control the first overflow valve to have smaller overflow pressure, so that the first pipeline can keep lower oil pressure, the rotary motor can output smaller torque to meet the requirement of the vehicle on the rotary torque at the moment, the rotary motor can be prevented from being in a high-pressure state, the abrasion of the rotary motor is reduced, and the service life of the rotary motor is prolonged.

As a preferred technical scheme of the rotary hydraulic system, the rotary hydraulic system further comprises a vehicle body inclination angle sensor and an oil cylinder pressure sensor which are connected with the controller, wherein the vehicle body inclination angle sensor is used for collecting the inclination angle of the vehicle body, and the oil cylinder pressure sensor is used for collecting the oil pressure of the movable arm oil cylinder.

The real-time inclination angle of the vehicle body is acquired through the inclination angle sensor and sent to the controller, the controller compares the real-time inclination angle with a preset inclination angle preset in the controller, whether the vehicle is in a half-slope operation working condition or not can be judged, the real-time oil pressure of the movable arm oil cylinder is acquired through the oil cylinder pressure sensor and is started to the controller, the controller compares the real-time oil pressure with a preset oil pressure preset in the controller, and whether the vehicle is in a heavy-load operation working condition or not can be judged. If the controller judges that the vehicle is in the half-slope operation working condition and in the heavy-load operation working condition, the controller can control the overflow pressure of the first overflow valve to increase so that the rotary motor outputs larger torque, and if the controller judges that the vehicle is not in the half-slope operation working condition or the controller judges that the vehicle is not in the heavy-load operation working condition, the controller can control the overflow pressure of the first overflow valve to decrease. So that the rotary motor outputs smaller torque and is prevented from being in a high-pressure state.

As a preferred technical solution of the rotary hydraulic system, the rotary hydraulic system further includes a control valve connected to an output end of the oil pump, and the control valve is connected to two ends of the rotary motor through a first pipeline and a second pipeline respectively, the control valve controls one of the first pipeline and the second pipeline to be communicated with the output end of the oil pump, and the other of the first pipeline and the second pipeline to be communicated with the oil tank, and the first overflow valve is connected to the first pipeline and the oil tank;

and the second overflow valve is connected with the second pipeline and the oil tank, the controller is connected with the second overflow valve, and the controller can control the overflow pressure of the second overflow valve.

When the control valve controls the first pipeline to be connected with the output end of the oil pump, and the second pipeline is connected with the oil tank, the rotary motor can output torque rotating along the first direction, and the controller controls the output torque of the rotary motor by controlling the overflow pressure of the first overflow valve; when the control valve controls the second pipeline to be connected with the output end of the oil pump, and the first pipeline is connected with the oil tank, the rotary motor can output torque rotating along the second direction. Thus, the output direction of the swing motor can be controlled by the control valve, and the controller controls the output torque of the swing motor by controlling the relief pressure of the second relief valve. Wherein, one of the first reverse direction and the second direction is clockwise, and the other is anticlockwise.

As a preferred technical scheme of the rotary hydraulic system, the first overflow valve and the second overflow valve are both two-section overflow valves.

The two-section overflow valve has two different overflow pressures, the structure is simple, and the control strategy is relatively simple.

As a preferred technical scheme of the rotary hydraulic system, the first overflow valve and the second overflow valve are both electro-hydraulic proportional overflow valves.

The electro-hydraulic proportional overflow valve can adjust the overflow pressure according to the output current value, can realize the continuous adjustment of the oil pressure of the first pipeline or the second pipeline, and the controller can match the overflow pressure of the first overflow valve and the second overflow valve according to the actual turning moment requirement of a vehicle, so that the energy can be saved to the maximum degree.

As a preferred embodiment of the swing hydraulic system, the swing hydraulic system further includes a first check valve and a second check valve, the first check valve connects the first line and the tank, and the first check valve is configured to allow only oil to flow from the tank to the first line; the second check valve connects the second line to a tank, the second check valve configured to only allow oil to flow from the tank to the second line.

When the vehicle is rotated, the rotation motor can continue to rotate under the inertia, but the oil pump stops supplying oil at the moment, and the arrangement of the first one-way valve and the second one-way valve can enable the rotation motor to suck oil from the oil tank at the moment, so that the rotation motor is prevented from sucking the oil in the first pipeline or the second pipeline to be empty.

As the preferred technical scheme of the rotary hydraulic system, the control valve is a three-position four-way valve and is provided with a left position, a right position and a middle position;

when the control valve is positioned at a left position, the control valve is communicated with the first pipeline and the output end of the oil pump, and the control valve is communicated with the second pipeline and the oil tank; when the control valve is positioned at the right position, the control valve is communicated with the second pipeline and the output end of the oil pump, and the control valve is communicated with the first pipeline and the oil tank; when the control valve is located at the middle position, the first pipeline and the second pipeline are disconnected with the output end of the oil pump, and the first pipeline and the second pipeline are disconnected with the oil tank.

When the control valve is located at the left position, the controllable rotary motor can drive the vehicle body to rotate along the first direction, and when the control valve is located at the right position, the controllable rotary motor can drive the vehicle body to rotate along the second direction. When the control valve is positioned at the middle position, the first pipeline and the second pipeline are both cut off, the rotary motor cannot rotate at the moment, the position of the vehicle body can be kept unchanged, and the rotation is avoided.

In another aspect, the present invention provides a method of controlling a swing hydraulic system according to any one of the above aspects, including:

judging whether the vehicle is in a semi-slope heavy-load operation working condition or not;

if the vehicle is in a semi-slope heavy-load working condition, the controller controls the first overflow valve to work at a first overflow pressure;

and if the vehicle is not in a semi-slope heavy-load working condition, the controller controls the first overflow valve to work at a second overflow pressure, and the first overflow pressure is greater than the second overflow pressure.

If the controller judges that the vehicle is in the semi-slope heavy-load operation working condition, the vehicle body rotates the required larger moment, the controller can control the overflow pressure of the first overflow valve to be the larger first overflow pressure, so that the first pipeline keeps larger driving oil pressure, the rotary motor outputs larger moment, and the vehicle can normally rotate under the semi-slope heavy-load operation working condition. If the controller judges that the vehicle is not in the semi-slope heavy-load operation working condition, at the moment, the vehicle body rotates the required smaller moment, the controller can control the overflow pressure of the first overflow valve to be the smaller first overflow pressure, so that the first pipeline keeps smaller driving oil pressure, the rotary motor outputs smaller moment, the vehicle can normally rotate under the non-semi-slope heavy-load operation working condition, and abrasion and service life reduction caused by the fact that the rotary motor is in a high-pressure state for a long time can be avoided.

As an optimal technical scheme of a control method of a rotary hydraulic system, a method for judging whether a vehicle is in a half-slope heavy-load working condition comprises the following steps:

collecting a real-time inclination angle α of the vehicle and collecting a real-time oil pressure P of a movable arm oil cylinder;

comparing the real-time inclination angle α with a preset inclination angle α 1 and the real-time oil pressure P with a preset oil pressure P1;

if α is more than or equal to α 1 and P is more than or equal to P1, the vehicle is judged to be in a half-slope heavy-load working condition;

and if α is less than α 1, and/or P is less than P1, determining that the vehicle is not in the half-slope heavy-load operation condition.

The real-time inclination angle of the vehicle body is acquired through the vehicle body inclination angle sensor and sent to the controller, the controller compares the real-time inclination angle with a preset inclination angle preset in the controller, whether the vehicle is in a half-slope operation working condition or not can be judged, the real-time oil pressure of the movable arm oil cylinder is acquired through the oil cylinder pressure sensor and is started to the controller, the controller compares the real-time oil pressure with a preset oil pressure preset in the controller, and whether the vehicle is in a heavy-load operation working condition or not can be judged. The controller integrates the judgment results of the two, and can obtain whether the vehicle is in the half-slope heavy-load working condition.

In a further aspect the present invention provides an excavator comprising a swing hydraulic system as described in any preceding aspect.

When the excavator works on a semi-slope, the rotary motor can provide large moment to ensure normal rotation of the excavator, and when the excavator works on the flat ground, on the premise of ensuring normal rotation of the excavator, the rotary motor can provide small moment to avoid abrasion and service life reduction caused by the fact that the rotary motor is in a high-pressure state for a long time.

The invention has the beneficial effects that:

the invention provides a slewing hydraulic system, a control method of the slewing hydraulic system and an excavator. The oil pump passes through first pipeline connection oil tank and rotary motor, and first pipeline and oil tank are connected to first overflow valve, and the controller is connected with first overflow valve and is used for controlling the overflow pressure of first overflow valve. When the vehicle is in the semi-slope rotary operation and rotates from a low position to a high position, the controller can control the first overflow valve to have larger overflow pressure, the first pipeline can keep higher oil pressure, and the rotary motor can output larger torque so as to meet the requirement of the vehicle on the rotary torque at the moment; when the vehicle is in flat ground operation, the controller can control the first overflow valve to have smaller overflow pressure, the first pipeline can keep lower oil pressure, the rotary motor can output smaller torque, the rotary motor can be prevented from being in a high-pressure state for a long time, the abrasion of the rotary motor is reduced, and the service life of the rotary motor is prolonged.

Drawings

FIG. 1 is a schematic structural diagram of a rotary hydraulic system according to a first embodiment of the present invention;

FIG. 2 is a first flowchart of a method for controlling a swing hydraulic system according to a second embodiment of the present invention;

fig. 3 is a second flowchart of a control method of a swing hydraulic system according to a second embodiment of the present invention.

In the figure:

1. an oil pump; 2. a rotary motor; 3. a first overflow valve; 4. a second overflow valve; 5. a controller; 6. a first pipeline; 7. a second pipeline; 8. a vehicle body inclination angle sensor; 9. a cylinder pressure sensor; 10. a control valve; 11. a first check valve; 12. a second one-way valve; 13. and an oil tank.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Where the terms "first position" and "second position" are two different positions, and where a first feature is "over", "above" and "on" a second feature, it is intended that the first feature is directly over and obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

Example one

As shown in fig. 1, the present embodiment provides a swing hydraulic system that includes an oil pump 1, a swing motor 2, a first relief valve 3, and a controller 5. Wherein, the input end of the oil pump 1 is connected with the oil tank 13; the rotary motor 2 is used for driving a vehicle body to rotate, the output end of the oil pump 1 is connected with the rotary motor 2 through a first pipeline 6, and the first overflow valve 3 is connected with the first pipeline 6 and the oil tank 13; the controller 5 is connected to the first relief valve 3 and is configured to control a relief pressure of the first relief valve 3. In the hydraulic swing system provided in this embodiment, the controller 5 controls the relief pressure of the first relief valve 3 to adjust the oil pressure of the first pipeline 6, thereby adjusting the driving oil pressure of the swing motor 2. When the vehicle is in the semi-slope rotary operation and rotates from a low position to a high position, the controller 5 can control the first overflow valve 3 to have larger overflow pressure, so that the first pipeline 6 can keep higher oil pressure, and the rotary motor 2 can output larger torque to meet the requirement of the vehicle on the rotary torque at the moment; when the vehicle is in flat ground operation, the controller 5 can control the first overflow valve 3 to have smaller overflow pressure, so that the first pipeline 6 can keep lower oil pressure, the rotary motor 2 can output smaller torque to meet the requirement of the vehicle on the rotary torque at the moment, the rotary motor 2 can be prevented from being in a high-pressure state, the abrasion of the rotary motor 2 is reduced, and the service life of the rotary motor 2 is prolonged.

Optionally, the swing hydraulic system further includes a vehicle body inclination angle sensor 8 and a cylinder pressure sensor 9 connected to the controller 5, the vehicle body inclination angle sensor 8 is configured to acquire an inclination angle of the vehicle body, and the cylinder pressure sensor 9 is configured to acquire an oil pressure of the boom cylinder. The real-time inclination angle of the vehicle body is collected through the vehicle body inclination angle sensor 8 and sent to the controller 5, the controller 5 compares the real-time inclination angle with a preset inclination angle preset in the controller 5, whether the vehicle is in a half-slope operation working condition or not can be judged, the real-time oil pressure of the movable arm oil cylinder is collected through the oil cylinder pressure sensor 9 and is started to the controller 5, the controller 5 compares the real-time oil pressure with the preset oil pressure preset in the controller 5, and whether the vehicle is in a heavy-load operation working condition or not can be judged. If the controller 5 judges that the vehicle is in the half-slope operation working condition and in the heavy-load operation working condition, the controller 5 can control the overflow pressure of the first overflow valve 3 to be increased so that the rotary motor 2 outputs a large torque, and if the controller 5 judges that the vehicle is not in the half-slope operation or the controller 5 judges that the vehicle is not in the heavy-load operation working condition, the controller 5 can control the overflow pressure of the first overflow valve 3 to be reduced so that the rotary motor 2 outputs a small torque and the rotary motor 2 is prevented from being in a high-pressure state.

It can be understood that the rotary motor 2 can be connected with the oil tank 13 through an oil pipe, the oil pump 1 supplies oil to the rotary motor 2 through the first pipeline 6, and then the oil flows back to the oil tank 13 through the oil pipe, but at this time, the direction of the torque output by the rotary motor 2 is fixed, the rotary motor 2 can only drive the vehicle body to rotate in a fixed direction, and assuming that the rotary motor 2 can only drive the vehicle body to rotate in a clockwise direction, when the real-time working condition requires that the vehicle rotates in an anticlockwise direction of the current position, and the rotating angle is an acute angle α, the vehicle can only be driven by the rotary motor 2 to rotate 360 degrees to α degrees, so that the working efficiency of the vehicle is reduced, and the energy waste is serious.

In this regard, in the present embodiment, the swing hydraulic system further includes a control valve 10 and a second relief valve 4. Wherein, control valve 10 is connected with the output of oil pump 1, and control valve 10 is connected with the both ends of rotary motor 2 through first pipeline 6 and second pipeline 7 respectively, and control valve 10 can control in first pipeline 6 and the second pipeline 7 one with the output intercommunication of oil pump 1, another and oil tank 13 intercommunication, and first pipeline 6 and oil tank 13 are connected to first overflow valve 3. The second overflow valve 4 is connected with the second pipeline 7 and the oil tank 13, the controller 5 is connected with the second overflow valve 4, and the controller 5 can control the overflow pressure of the second overflow valve 4. When the control valve 10 controls the first pipeline 6 to be connected with the output end of the oil pump 1 and the second pipeline 7 is connected with the oil tank 13, the rotary motor 2 can output torque rotating along a first direction, and the controller 5 controls the output torque of the rotary motor 2 by controlling the overflow pressure of the first overflow valve 3; when the control valve 10 controls the second pipeline 7 to be connected with the output end of the oil pump 1 and the first pipeline 6 to be connected with the oil tank 13, the rotary motor 2 can output torque rotating along the second direction, and the controller 5 controls the output torque of the rotary motor 2 by controlling the overflow pressure of the second overflow valve 4. Wherein, among first direction and the second direction, one is clockwise, and another is anticlockwise to, can be according to actual need, through the output direction of the moment of control valve 10 control rotary motor 2, make the automobile body at a less angle, be not more than 180 within range rotations, can realize the switching of operation position, and can guarantee the work efficiency of vehicle, avoid the energy extravagant.

In this embodiment, the controller 5 controls the output torque of the rotary motor 2 by controlling the relief pressure of the second relief valve 4, specifically: when the control valve 10 controls the second pipeline 7 to be connected with the output end of the oil pump 1, the first pipeline 6 is connected with the oil tank 13, the vehicle body inclination angle sensor 8 collects a real-time inclination angle of a vehicle body and sends the real-time inclination angle to the controller 5, the oil cylinder pressure sensor 9 collects a real-time oil pressure of the movable arm oil cylinder and sends the real-time oil pressure to the controller 5, the controller 5 compares the real-time inclination angle with a preset inclination angle preset in the controller 5, the real-time oil pressure is compared with a preset oil pressure preset in the controller 5, and only when the real-time inclination angle is not smaller than the preset angle and the real-time oil pressure is not smaller than the preset oil pressure, the. At this time, the controller 5 may control the relief pressure of the second relief valve 4 to increase, so that the swing motor 2 outputs a large torque to ensure sufficient power swing of the vehicle. If the controller 5 judges that the vehicle is not in the semi-slope heavy-load working condition, the controller 5 can control the overflow pressure of the second overflow valve 4 to be reduced, so that the rotary motor 2 outputs smaller torque, the rotary motor 2 is prevented from being in a high-pressure state, the rotary motor 2 can be prevented from being abraded, and the service life of the rotary motor 2 is prolonged.

Specifically, in the present embodiment, the control valve 10 is a three-position four-way valve, and the control valve 10 has a left position, a right position and a middle position. When the control valve 10 is positioned at the left position, the control valve 10 is communicated with the first pipeline 6 and the output end of the oil pump 1, and the control valve 10 is communicated with the second pipeline 7 and the oil tank 13; when the control valve 10 is positioned at the right position, the control valve 10 is communicated with the second pipeline 7 and the output end of the oil pump 1, and the control valve 10 is communicated with the first pipeline 6 and the oil tank 13; when the control valve 10 is located at the neutral position, the first pipeline 6 and the second pipeline 7 are both disconnected from the output end of the oil pump 1, and the first pipeline 6 and the second pipeline 7 are both disconnected from the oil tank 13. When the control valve 10 is in the left position, the swing motor 2 may be controlled to rotate the vehicle body in the first direction, and when the control valve 10 is in the right position, the swing motor 2 may be controlled to rotate the vehicle body in the second direction. When the control valve 10 is located at the middle position, the first pipeline 6 and the second pipeline 7 are both cut off, the rotary motor 2 cannot rotate at the moment, the position of the vehicle body can be kept unchanged, and the rotation is avoided. In this embodiment, the driver can control the control valve 10 to switch between the left position, the right position and the middle position by operating the handle, wherein the technology of controlling the control valve 10 by operating the handle is the prior art, and is not described herein again.

The first and second relief valves 3 and 4 may be both two-stage relief valves. The two-section overflow valve has two different overflow pressures, the structure is simple, and the control strategy is relatively simple. When the first overflow valve 3 is controlled to have a small overflow pressure, the first overflow valve 3 may overflow the first pipeline 6, and the first pipeline 6 maintains a low oil pressure, so that the driving oil pressure of the rotary motor 2 rotating in the first direction is maintained at a small value; when the first relief valve 3 is controlled to have a large relief pressure, the first relief valve 3 relieves the first pipe 6, and the first pipe 6 maintains a high oil pressure, so that the driving oil pressure of the rotary motor 2 rotating in the first direction is maintained at a large value. Similarly, when the second overflow valve 4 is controlled to have a smaller overflow pressure, the second overflow valve 4 may overflow the second pipeline 7, and the second pipeline 7 maintains a lower oil pressure, so that the driving oil pressure of the rotary motor 2 rotating in the second direction is maintained to be a smaller value; when the second relief valve 4 is controlled to a large relief pressure, the second relief valve 4 relieves the second line 7, and the second line 7 maintains a high oil pressure, thereby maintaining the maximum driving oil pressure when the swing motor 2 is rotated in the second direction.

The first overflow valve 3 and the second overflow valve 4 can also be both electro-hydraulic proportional overflow valves. The electro-hydraulic proportional overflow valve can adjust the overflow pressure according to the output current value, can realize the continuous adjustment of the oil pressure of the first pipeline 6 or the second pipeline 7, and the controller 5 can match the overflow pressure of the first overflow valve 3 and the second overflow valve 4 according to the actual turning moment requirement of a vehicle, so that the energy can be saved to the maximum degree. Of course, in other embodiments, one of the first relief valve 3 and the second relief valve 4 may be a two-stage relief valve, and the other of the first relief valve 3 and the second relief valve 4 may be an electro-hydraulic proportional relief valve.

Optionally, the swing hydraulic system further comprises a first check valve 11 and a second check valve 12, the first check valve 11 connecting the first line 6 and the tank 13, the first check valve 11 being configured to only allow oil to flow from the tank 13 to the first line 6; a second non return valve 12 connects the second line 7 with the tank 13, the second non return valve 12 being configured to only allow oil to flow from the tank 13 to the second line 7. When the vehicle finishes rotating, the rotating motor 2 can continue to rotate under inertia, but the oil pump 1 stops supplying oil at the moment, and the arrangement of the first check valve 11 and the second check valve 12 can enable the rotating motor 2 to suck oil from the oil tank 13 at the moment, so that the rotating motor 2 is prevented from sucking the oil in the first pipeline 6 or the second pipeline 7 to be empty.

The working principle of the rotary hydraulic system is as follows:

the oil pump 1 sucks oil from the oil tank 13 and delivers the oil to the control valve 10, when the control valve 10 is located at the left position, the oil flows to the rotary motor 2 through the first pipeline 6 and drives the rotary motor 2 to rotate along the first direction, and the oil flows to the control valve 10 through the second pipeline 7 and flows to the oil tank 13 through the control valve 10. When the control valve 10 is in the neutral position, the control valve 10 disconnects the oil pump 1 from the first pipeline 6 and the second pipeline 7, and simultaneously, the control valve 10 disconnects the oil tank 13 from the first pipeline 6 and the second pipeline 7, so that the rotary motor 2 maintains a fixed position, and the position of the vehicle body is kept unchanged. When the control valve 10 is in the right position, the oil flows to the rotary motor 2 through the second pipeline 7 and drives the rotary motor 2 to rotate in the second direction, and the oil flows to the control valve 10 through the first pipeline 6 and flows to the oil tank 13 through the control valve 10.

When the oil pump 1 is closed and the control valve 10 is in the left position, if the rotary motor 2 continues to rotate in the first direction under inertia, the rotary motor 2 draws oil from the oil tank 13 through the first check valve 11 and via the first line 6, and the oil flows back to the oil tank 13 via the second line 7.

When the oil pump 1 is closed and the control valve 10 is in the right position, if the rotary motor 2 continues to rotate in the second direction under inertia, the rotary motor 2 draws oil from the oil tank 13 through the second check valve 12 and via the second line 7, the oil flowing back to the oil tank 13 via the first line 6.

Example two

As shown in fig. 2, the present embodiment provides a control method of a hydraulic swing system, which is applied to the hydraulic swing system in the first embodiment, and the control method of the hydraulic swing system includes the following steps:

s1: and judging whether the vehicle is in a semi-slope heavy-load operation working condition or not.

S2: if the vehicle is in a half-slope heavy-load working condition, the controller 5 controls the first overflow valve 3 to work at a first overflow pressure.

S3: if the vehicle is not in the half slope heavy load working condition, the controller 5 controls the first overflow valve 3 to work at a second overflow pressure, and the first overflow pressure is greater than the second overflow pressure.

If the controller 5 judges that the vehicle is in the heavy-load operation working condition of the half slope, the vehicle body needs larger moment when rotating, the controller 5 can control the overflow pressure of the first overflow valve 3 to be larger first overflow pressure, so that the first pipeline 6 keeps larger driving oil pressure, the rotary motor 2 outputs larger moment, and the vehicle can normally rotate under the heavy-load operation working condition of the half slope. If the controller 5 judges that the vehicle is not in the semi-slope heavy-load operation working condition, at the moment, the vehicle body needs smaller moment in rotation, the controller 5 can control the overflow pressure of the first overflow valve 3 to be smaller first overflow pressure so as to enable the first pipeline 6 to keep smaller driving oil pressure, the rotary motor 2 outputs smaller moment, the vehicle can normally rotate under the non-semi-slope heavy-load operation working condition, and abrasion and service life reduction caused by the fact that the rotary motor 2 is in a high-pressure state for a long time can be avoided.

As shown in fig. 3, the method for determining whether the vehicle is in the half-slope heavy-load operation condition includes:

and S11, acquiring a real-time inclination angle α of the vehicle and acquiring a real-time oil pressure P of the boom cylinder.

S12, comparing the real-time inclination angle α with the preset inclination angle α 1 and the real-time oil pressure P with the preset oil pressure P1.

S13, if α is not less than α 1 and P is not less than P1, the vehicle is judged to be in the half-slope heavy-load operation condition.

And S14, if α is less than α 1 and/or P is less than P1, the vehicle is judged not to be in the half-slope heavy-load operation condition.

Accessible automobile body inclination sensor 8 gathers the real-time inclination of automobile body and sends for controller 5, and controller 5 compares real-time inclination with the inclination of predetermineeing in controller 5 of predetermineeing, can judge whether the vehicle is in the half slope operation operating mode, gathers the real-time oil pressure of movable arm hydro-cylinder and starts for controller 5 through hydro-cylinder pressure sensor 9, and controller 5 compares real-time oil pressure with the oil pressure of predetermineeing in controller 5 of predetermineeing, can judge whether the vehicle is in the heavy load operation operating mode. The controller 5 integrates the judgment results of the two, and can obtain whether the vehicle is in the half-slope heavy-load working condition.

Optionally, the swing hydraulic system further comprises a control valve 10 and a second spill valve 4. The control valve 10 is a three-position four-way valve.

When the control valve 10 is in the left position, the control method of the swing hydraulic system is as described in the above S1 to S3. When the control valve 10 is located at the right position, the method of manufacturing the swing hydraulic system further includes:

s4: and judging whether the vehicle is in a semi-slope heavy-load operation working condition or not.

S5: if the vehicle is in a half-slope heavy-load working condition, the controller 5 controls the second overflow valve 4 to work at a third overflow pressure.

S6: if the vehicle is not in the half slope heavy-load working condition, the controller 5 controls the second overflow valve 4 to work at a fourth overflow pressure, and the third overflow pressure is greater than the fourth overflow pressure.

Step S4 is the same as step S1.

It should be noted that when the first overflow valve 3 and the second overflow valve 4 are both electro-hydraulic proportional overflow valves, a linear relationship map1 between the overflow pressure of the first overflow valve 3 and the inclination angle of the vehicle body, a linear relationship map2 between the overflow pressure of the first overflow valve 3 and the control current of the first overflow valve 3, and a linear relationship map3 between the overflow pressure of the second overflow valve 4 and the inclination angle of the vehicle body are preset in the controller 5, and a linear relationship map4 between the overflow pressure of the second overflow valve 4 and the control current of the second overflow valve 4. when it is determined that the vehicle is in the half-slope heavy-duty working condition, taking the control valve 10 as an example when the vehicle is located at the left position, the controller 5 obtains the overflow pressure of the first overflow valve 3 corresponding to the real-time inclination angle α from the map1 according to the real-time inclination angle α of the vehicle body, searches the control current I1 of the corresponding first overflow valve 3 from the map2, and changes the control current of the first overflow valve 3 to I1.

EXAMPLE III

The embodiment provides an excavator comprising the slewing hydraulic system in the first embodiment, and the excavator can have the corresponding beneficial effects of the slewing hydraulic system. When the excavator works on a heavy load on a semi-slope, the rotary motor 2 can provide large moment to ensure normal rotation of the excavator, and when the excavator works on a flat ground or works on a light load on the semi-slope, on the premise of ensuring normal rotation of the excavator, the rotary motor 2 can provide small moment, so that abrasion and service life reduction caused by the fact that the rotary motor 2 is in a high-pressure state for a long time can be avoided.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A swing hydraulic system, comprising:

the input end of the oil pump (1) is connected with the oil tank (13);

the rotary motor (2) is used for driving the machine body to rotate, and the output end of the oil pump (1) is connected with the rotary motor (2) through a first pipeline (6);

a first overflow valve (3) connecting the first pipeline (6) and the oil tank (13);

and the controller (5) is connected with the first overflow valve (3) and is used for controlling the overflow pressure of the first overflow valve (3).

2. The rotary hydraulic system according to claim 1, further comprising a body tilt sensor (8) and a cylinder pressure sensor (9) connected to the controller (5), wherein the body tilt sensor (8) is configured to acquire a tilt angle of the body, and the cylinder pressure sensor (9) is configured to acquire an oil pressure of a boom cylinder.

3. The swing hydraulic system according to claim 1 or 2, further comprising:

the control valve (10) is connected with the output end of the oil pump (1), the control valve (10) is respectively connected with two ends of the rotary motor (2) through a first pipeline (6) and a second pipeline (7), the control valve (10) can control one of the first pipeline (6) and the second pipeline (7) to be communicated with the output end of the oil pump (1) and the other one of the first pipeline (6) and the second pipeline (7) to be communicated with the oil tank (13), and the first overflow valve (3) is connected with the first pipeline (6) and the oil tank (13);

the second overflow valve (4) is connected with the second pipeline (7) and the oil tank (13), the controller (5) is connected with the second overflow valve (4), and the controller (5) can control the overflow pressure of the second overflow valve (4).

4. A rotary hydraulic system according to claim 3, characterized in that the first overflow valve (3) and the second overflow valve (4) are both two-stage overflow valves.

5. A rotary hydraulic system according to claim 3, characterized in that the first overflow valve (3) and the second overflow valve (4) are both electro-hydraulic proportional overflow valves.

6. A swing hydraulic system according to claim 3, further comprising a first check valve (11) and a second check valve (12), the first check valve (11) connecting the first line (6) and the tank (13), the first check valve (11) being configured to only allow oil to flow from the tank (13) to the first line (6); the second non return valve (12) connects the second line (7) and a tank (13), the second non return valve (12) being configured to allow oil to flow only from the tank (13) to the second line (7).

7. The swing hydraulic system according to claim 3, wherein the control valve (10) is a three-position, four-way valve, the control valve (10) having a left position, a right position and a neutral position;

when the control valve (10) is positioned at a left position, the control valve (10) is communicated with the first pipeline (6) and the output end of the oil pump (1), and the control valve (10) is communicated with the second pipeline (7) and the oil tank (13); when the control valve (10) is positioned at the right position, the control valve (10) is communicated with the second pipeline (7) and the output end of the oil pump (1), and the control valve (10) is communicated with the first pipeline (6) and the oil tank (13); when the control valve (10) is located at the middle position, the first pipeline (6) and the second pipeline (7) are disconnected with the output end of the oil pump (1), and the first pipeline (6) and the second pipeline (7) are disconnected with the oil tank (13).

8. A method of controlling a swing hydraulic system according to any one of claims 1 to 7, comprising:

judging whether the vehicle is in a semi-slope heavy-load operation working condition or not;

if the vehicle is in a semi-slope heavy-load working condition, the controller (5) controls the first overflow valve (3) to work at a first overflow pressure;

if the vehicle is not in a semi-slope heavy-load working condition, the controller (5) controls the first overflow valve (3) to work at a second overflow pressure, and the first overflow pressure is larger than the second overflow pressure.

9. The method for controlling the rotary hydraulic system of claim 8, wherein the method for determining whether the vehicle is in a heavy-duty half-hill operation condition comprises:

collecting a real-time inclination angle α of the vehicle and collecting a real-time oil pressure P of a movable arm oil cylinder;

comparing the real-time inclination angle α with a preset inclination angle α 1 and the real-time oil pressure P with a preset oil pressure P1;

if α is more than or equal to α 1 and P is more than or equal to P1, the vehicle is judged to be in a half-slope heavy-load working condition;

and if α is less than α 1, and/or P is less than P1, determining that the vehicle is not in the half-slope heavy-load operation condition.

10. An excavator comprising a swing hydraulic system as claimed in any one of claims 1 to 7.

Images