CN117846058A - Hydraulic excavator energy-saving system - Google Patents

Abstract

The invention discloses an energy-saving system of a hydraulic excavator, which is characterized in that when a movable arm oil cylinder descends, redundant hydraulic oil in a large cavity of the movable arm oil cylinder is recovered by a movable arm energy recovery device, so that the problem that after gravitational potential energy of the movable arm is converted into hydraulic energy by the movable arm oil cylinder when the movable arm of the hydraulic excavator descends, the hydraulic energy is converted into heat energy dissipation waste by each throttle opening of the hydraulic system of the hydraulic excavator, and the aim of recovering the descending energy of the movable arm is fulfilled. When the rotary motor is started, the surplus flow in the rotary motor cavity is recovered by the rotary energy recovery device, so that the anti-overflow effect of rotary starting is realized. Or, when the rotary motor is braked, the rotary energy recovery device is utilized to recover the surplus energy during the rotary motor braking, thereby realizing the recovery of the rotary braking energy.

Description

Hydraulic excavator energy-saving system

Technical Field

The invention relates to the technical field of engineering machinery, in particular to an energy-saving system of a hydraulic excavator.

Background

The hydraulic excavator has wide application in the technical fields of buildings, bridges, high-speed rails, tunnels, wharfs, military industry and the like. As the market volume of hydraulic excavators increases, the cumulative fuel consumption of the hydraulic excavators becomes a main source of petrochemical energy consumption following the automobiles, and therefore, how to save energy and reduce emissions becomes a trend of the hydraulic excavators.

In the prior art, when the hydraulic excavator works, a great amount of energy is dissipated in a thermal mode, for example, when the movable arm descends, gravitational potential energy is converted into hydraulic energy through the hydraulic cylinder and then is converted into heat energy through each throttling port of the hydraulic system to be dissipated. For another example, when the hydraulic excavator is started in a turning mode, the rotation speed of the turning motor is low, the required flow is small, and the output flow of the hydraulic pump part overflows through the turning motor overflow valve, so that the hydraulic pump part is finally lost in a heat mode. When the hydraulic excavator is braked in a rotary mode, the kinetic energy is large when the rotary platform is braked because the mass, the rotational inertia and the moment of inertia of the rotary platform and the working device are large, and the kinetic energy is generally lost in the form of heat energy.

When the movable arm of the hydraulic excavator descends and rotates, a large amount of energy is wasted through heating, the temperature of hydraulic oil can be rapidly increased, the cooling cost is increased, and the system power consumption is further increased.

In view of the above, how to recover the descending energy and the swing start or swing brake energy of the hydraulic excavator is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention is to provide an energy-saving system for a hydraulic excavator, which can recover the descending energy of the movable arm of the hydraulic excavator and the swing starting or swing braking energy.

In order to achieve the above object, the present invention provides the following technical solutions:

the energy-saving system of the hydraulic excavator comprises a movable arm oil cylinder, a rotary motor and at least one of a movable arm energy recovery device and a rotary energy recovery device;

the movable arm energy recovery device is connected with the large cavity of the movable arm oil cylinder and is used for recovering energy when the movable arm of the hydraulic excavator descends;

the swing energy recovery device is connected with the cavity of the swing motor and is used for recovering at least one of swing starting energy and swing braking energy.

Optionally, the boom energy recovery device includes:

the flow extraction valve is connected with the large cavity;

a first accumulator connected to the flow extraction valve;

when the movable arm of the hydraulic excavator descends, the flow extraction valve is opened, so that redundant hydraulic oil in the large cavity flows into the first energy accumulator.

Optionally, the method further comprises:

a flow saturation valve connected between the flow extraction valve and an oil tank of the hydraulic excavator;

the first pressure reading device is arranged at the outlet of the flow extraction valve;

when the movable arm of the hydraulic excavator descends and the pressure of the first pressure reading device exceeds a first set value, the flow saturation valve is opened, so that redundant hydraulic oil in the large cavity flows into the oil tank through the flow extraction valve and the flow saturation valve.

Optionally, a controllable regeneration valve is connected between the large cavity and the small cavity of the movable arm oil cylinder;

when the hydraulic excavator boom is lowered, the controllable regeneration valve opens.

Optionally, an anti-sedimentation valve is arranged at the outlet of the large cavity, the anti-sedimentation valve is connected with a main valve movable arm of the hydraulic excavator in a linkage mode, and the flow extraction valve is connected with the anti-sedimentation valve.

Optionally, the opening degree of the flow extraction valve and the main valve movable arm link are adjustable.

Optionally, the rotational energy recovery device includes:

the flow recovery valve is respectively connected with the cavity A and the cavity B of the rotary motor;

the second energy accumulator is connected with the flow recovery valve;

when the rotary motor is started and the pressure of the cavity A or the cavity B is larger than a third set value, the flow recovery valve is opened, so that redundant hydraulic oil of the cavity A or the cavity B flows into the second energy accumulator.

Optionally, the method further comprises:

the hydraulic lock is arranged between the rotary motor and a main valve rotary joint of the hydraulic excavator; when the rotary motor brakes, the hydraulic lock is closed; and when the rotary motor brakes and the pressure of the cavity A or the cavity B is larger than the third set value, the flow recovery valve is opened, so that redundant hydraulic oil of the cavity A or the cavity B flows into the second energy accumulator.

Optionally, a back pressure valve is arranged between a main valve rotary joint of the hydraulic excavator and an oil tank of the hydraulic excavator, and oil supplementing one-way valves are respectively arranged between an A cavity and a B cavity of the rotary motor of the main valve rotary joint;

when the pressure of the cavity A or the cavity B is lower than the set pressure of the back pressure valve, hydraulic oil of a main pump of the hydraulic excavator supplements oil to the cavity A or the cavity B through the main valve rotary union and the oil supplementing one-way valve.

Optionally, the method further comprises:

the function selector valve is respectively connected with the movable arm energy recovery device and the rotary energy recovery device, and is respectively connected with an energy storage motor, a preset working device actuator loop, a heat dissipation motor and a power generation device 12 of the hydraulic excavator, and is used for distributing energy recovered by the movable arm energy recovery device and the rotary energy recovery device to the energy storage motor, the preset working device actuator loop, the heat dissipation motor and/or the power generation device.

According to the energy-saving system for the hydraulic excavator, when the movable arm oil cylinder descends, the movable arm energy recovery device is utilized to recover redundant hydraulic oil in a large cavity of the movable arm oil cylinder, so that the problem that after gravitational potential energy of the movable arm is converted into hydraulic energy through the movable arm oil cylinder when the movable arm of the hydraulic excavator descends, the hydraulic energy is converted into heat energy dissipation waste through each throttle opening of the hydraulic system of the hydraulic excavator, and the purpose of recovering the descending energy of the movable arm is achieved. In addition, when the rotary motor is started, the rotating speed of the rotary motor is low, the required flow is low, the partial output flow of the main pump of the hydraulic excavator is more than the rotary motor rotation required flow, the pressure in the rotary motor cavity is increased, when the pressure in the rotary motor cavity is overlarge, the surplus flow in the rotary motor cavity is recovered by the rotary energy recovery device, and the rotary starting overflow prevention is realized. Or when the rotary motor is braked, the rotary platform of the hydraulic excavator and the working device have large mass, moment of inertia and moment of inertia, and the rotary motor is not stopped immediately due to the inertia action, but continues to rotate for a certain angle in the original motion state, and at the moment, the rotary energy recovery device is utilized to recover the surplus energy when the rotary motor is braked, so that the recovery of the rotary braking energy is realized.

Therefore, the energy-saving system of the hydraulic excavator can recycle the energy when the movable arm descends by using the movable arm energy recycling device; and the rotary energy recovery device is used for recovering rotary starting energy and/or rotary braking energy, so that the energy conservation of the hydraulic excavator is realized, and the hydraulic excavator has great practical significance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings may be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a hydraulic schematic diagram of an energy saving system for a hydraulic excavator according to an embodiment of the present invention;

FIG. 2 is a block diagram of a boom energy recovery device;

FIG. 3 is a block diagram of a rotational energy recovery device;

fig. 4 is a block diagram of the structure of the recovered energy release.

Reference numerals in fig. 1 to 4 are as follows:

100 is a movable arm energy recovery device, 101 is a flow extraction valve, 102 is a first energy accumulator, 103 is a flow saturation valve, 104 is a first pressure reading device, 105 is a second pressure reading device, 106 is a controllable regeneration valve, and 107 is an anti-sedimentation valve;

200 is a rotary energy recovery device, 201 is a flow recovery valve, 202 is a second accumulator, 203 is a hydraulic lock, 204 is a back pressure valve, 205 is an oil supplementing one-way valve, and 206 is a safety valve;

the hydraulic control system comprises a main pump 1, a main valve 2, a main valve movable arm linkage 21, a main valve rotary linkage 22, a movable arm oil cylinder 3, a large cavity 31, a small cavity 32, a rotary motor 4, a cavity A41, a cavity B42, a bucket rod oil cylinder 5, an energy accumulator 6, a function selection valve 7, an energy storage motor 8, a heat dissipation motor 9, an oil tank 10, a preset working device actuator loop 11 and a power generation device 12.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention provides an energy-saving system of a hydraulic excavator, which can recycle descending energy and swing starting or swing braking energy of a movable arm of the hydraulic excavator.

Referring to fig. 1, an embodiment of the present invention provides an energy saving system for a hydraulic excavator, including a boom cylinder 3, a swing motor 4, and at least one of a boom energy recovery device 100 and a swing energy recovery device 200; the boom energy recovery device 100 is connected with the large cavity 31 of the boom cylinder 3 and is used for recovering energy when the boom descends; the swing energy recovery device 200 is connected to the chamber of the swing motor 4 for recovering at least one of swing start energy and swing brake energy.

That is, when the boom cylinder 3 is lowered, the redundant hydraulic oil in the large cavity 31 of the boom cylinder 3 is recovered by the boom energy recovery device 100, so that the gravitational potential energy of the boom is prevented from being converted into hydraulic energy by the boom cylinder 3 when the boom of the hydraulic excavator is lowered, and then converted into heat energy dissipation waste by each throttle opening of the hydraulic system of the hydraulic excavator, thereby achieving the purpose of recovering the boom lowering energy. When the swing motor 4 is started, the rotation speed of the swing motor 4 is low, the required flow rate is low, the partial output flow rate of the main pump 1 of the hydraulic excavator is more than the swing required flow rate of the swing motor 4, the pressure in the cavity of the swing motor 4 is increased, and when the pressure in the cavity of the swing motor 4 is excessive, the surplus flow rate in the cavity of the swing motor 4 is recovered by the swing energy recovery device 200, so that the swing start overflow prevention is realized. Or, when the swing motor 4 is braked, the swing platform of the hydraulic excavator and the working device have large mass, moment of inertia and moment of inertia, and the swing of the swing motor 4 is not stopped immediately due to the inertia, but the swing motor continues to swing for a certain angle in the original motion state, and at this time, the swing energy recovery device 200 is used for recovering the surplus energy when the swing motor 4 is braked, so as to realize recovery of the swing braking energy.

As can be seen, the hydraulic excavator energy saving system can recover energy when the boom descends by using the boom energy recovery device 100; and the rotary energy recovery device 200 is utilized to recover rotary starting energy and/or rotary braking energy, so that the energy conservation of the hydraulic excavator is realized, and the hydraulic excavator has great practical significance.

It should be noted that, the energy-saving system for a hydraulic excavator provided by the embodiment of the invention is that the boom energy recovery device 100 and the swing energy recovery device 200 are added on the basis of the existing hydraulic system of the hydraulic excavator, so that the hydraulic excavator has a new energy recovery function, and the energy recovery function can be selectively closed and does not conflict with the original system of the hydraulic excavator. That is, in some embodiments, the hydraulic excavator includes a normal operation mode in which the boom energy recovery device 100 and the swing energy recovery device 200 are closed, and an energy saving mode; in the energy saving mode, the boom energy recovery device 100 and the swing energy recovery device 200 operate under the control of the control device of the hydraulic excavator.

It can be understood that the hydraulic excavator energy saving system further comprises a main pump 1, a main valve 2, an oil tank 10 and the like, wherein the main valve 2 comprises a main valve movable arm link 21 and a main valve rotary link 22, the main valve movable arm link 21 is connected between the main pump 1 and a small cavity 32 of a movable arm oil cylinder 3, and the main valve rotary link 22 is connected between the main pump 1 and a rotary motor 4; the oil return port of the main valve 2 is connected with an oil tank 10; thus, oil inlet and oil return in a normal working mode can be realized.

Referring to fig. 2, considering the specific implementation of the boom energy recovery device 100, in some embodiments, the boom energy recovery device 100 includes a flow extraction valve 101 and a first accumulator 102, the flow extraction valve 101 being connected with the large chamber 31 of the boom cylinder 3; the first accumulator 102 is connected with the flow extraction valve 101; when the hydraulic excavator boom descends, the flow extraction valve 101 opens to allow excess hydraulic oil in the large chamber 31 to flow into the first accumulator 102.

That is, in this embodiment, a first oil return branch is formed between the large chamber 31 of the boom cylinder 3, the flow extraction valve 101 and the first accumulator 102, when the hydraulic excavator boom is lowered (for example, the hydraulic excavator is unloaded and returned), that is, the boom is in a suspended state, the large chamber 31 of the boom cylinder 3 is influenced by the gravity of the boom, at this time, the flow extraction valve 101 is opened, so that the redundant hydraulic oil in the large chamber 31 of the boom cylinder 3 flows into the first accumulator 102, and the boom lowering energy is stored by the first accumulator 102.

Further, the opening degree of the flow extraction valve 101 is adjustable so that the boom lowering speed is controllable by controlling the opening degree of the flow extraction valve 101 to adjust the excess flow, so that the operability is good, and the energy recovery is performed on the basis of ensuring the operability is good.

In addition, in some embodiments, when the hydraulic excavator excavates or props, the oil inlet throttling control is performed, and the opening area of the main valve movable arm link 21 of the hydraulic excavator is adjustable to adjust the overflow rate, so as to achieve the purpose of speed control.

The specific structure of the flow extraction valve 101 in this embodiment is not limited as long as it allows flow to pass when opened and can adjust the size of flow allowed to pass according to the boom down pilot pressure signal. The opening conditions are as follows: the working mode of the hydraulic excavator is an energy-saving mode, and a boom descending pilot signal is received. In the normal operation mode of the hydraulic excavator, the flow extraction valve 101 is closed, and the movement of the boom is completely controlled by the main valve boom linkage 21, as in the conventional hydraulic excavator of the prior art.

Further, with continued reference to fig. 2, in some embodiments, a flow saturation valve 103 and a first pressure reading device 104 are further included, the flow saturation valve 103 being connected between the flow extraction valve 101 and the tank 10 of the hydraulic excavator; the first pressure reading device 104 is arranged at the outlet of the flow extraction valve 101; when the hydraulic excavator boom descends and the pressure of the first pressure reading device 104 exceeds the first set value, the flow saturation valve 103 is opened so that the surplus hydraulic oil in the large chamber 31 of the boom cylinder 3 flows into the tank 10 via the flow extraction valve 101 and the flow saturation valve 103.

That is, the large chamber 31 of the boom cylinder 3, the flow extraction valve 101, the flow saturation valve 103, and the tank 10 form a second oil return branch, when the first accumulator 102 is fully loaded, the charging pressure is higher, and the pressure read by the first pressure reading device 104 exceeds the first set value, at this time, the flow saturation valve 103 is opened, so that the surplus hydraulic oil in the large chamber 31 of the boom cylinder 3 returns to the tank 10 via the flow extraction valve 101 and the flow saturation valve 103.

The specific structure of the flow saturation valve 103 is not limited in this embodiment, as long as the flow saturation valve 103 allows the flow to pass when opened, and the outlet and the inlet of the flow saturation valve 103 have a certain pressure drop. The opening conditions of the flow saturation valve 103 are: the working mode of the hydraulic excavator is an energy-saving mode, a boom lowering pilot signal is received, the pressure of the large cavity 31 of the boom cylinder 3 is larger than a preset value, and the pressure read by the first pressure reading device 104 exceeds a first set value. In the normal operation mode of the hydraulic excavator, the flow saturation valve 103 is closed.

In addition, with continued reference to fig. 2, in some embodiments, a controllable regeneration valve 106 is connected between the large chamber 31 and the small chamber 32 of the boom cylinder 3; when the hydraulic excavator boom is lowered, the controllable regeneration valve 106 opens.

That is, in this embodiment, by providing the controllable regeneration valve 106, a third oil return branch is formed between the large cavity 31 of the boom cylinder 3, the controllable regeneration valve 106, and the small cavity 32 of the boom cylinder 3, when the hydraulic excavator is in boom lowering, the controllable regeneration valve 106 is opened, so that hydraulic oil in the large cavity 31 of the boom cylinder 3 flows to the small cavity 32 of the boom cylinder 3, forming a differential loop, and avoiding the small cavity 32 of the boom cylinder 3 from sucking air. Since the large chamber 31 of the boom cylinder 3 is larger in area than the small chamber 32, there is a part of the surplus return oil flow, which flows to the first accumulator 102 through the flow extraction valve 101, and returns to the tank 10 through the flow extraction valve 101 and the flow saturation valve 103 when the first accumulator 102 is fully loaded.

In addition, the controllable regeneration valve 106 is arranged, when the movable arm of the hydraulic excavator is in idle load, the movable arm link 21 of the main valve of the hydraulic excavator is closed, and the main pump 1 of the hydraulic excavator only supplies oil to meet internal leakage, so that the energy loss is greatly reduced. In addition, compared with an incomplete regeneration valve, the large cavity 31 and the small cavity 32 of the movable arm cylinder 3 are completely communicated, the oil utilization rate of the large cavity 31 is high, the oil return amount of the large cavity 31 to the oil tank 10 is reduced, and the volume of an oil return element can be reduced. The pressure of the large cavity 31 is equal to that of the small cavity 32, and the pressure of the small cavity 32 is higher than that of the small cavity of the incomplete regeneration valve, so that the accumulator 6 is filled with liquid, and the pressure is built up faster when the movable arm rises.

In this embodiment, the specific structure of the controllable regeneration valve 106 is not limited, as long as the controllable regeneration valve 106 allows the flow to pass when opened. The opening conditions of the controllable regeneration valve 106 are: the working mode of the hydraulic excavator is an energy-saving mode, a boom descending pilot signal is received, and the pressure of the large cavity 31 of the boom cylinder 3 is larger than a preset value.

Further, with continued reference to fig. 2, in some embodiments, the outlet of the large chamber 31 of the boom cylinder 3 is provided with a second pressure reading device 105; when the hydraulic excavator boom descends and the pressure of the second pressure reading device 105 exceeds the second set point, the controllable regeneration valve 106 opens.

That is, in this embodiment, the second pressure reading device 105 is disposed at the outlet of the large cavity 31 of the boom cylinder 3 to monitor the pressure of the large cavity 31 of the boom cylinder 3 in real time, and when the pressure of the large cavity 31 of the boom cylinder 3 is greater than the preset value, that is, when the pressure of the second pressure reading device 105 exceeds the second set value, the controllable regeneration valve 106 is controlled to be opened.

In addition, referring to fig. 2, in some embodiments, the hydraulic excavator energy saving system further includes an anti-settling valve 107, where the anti-settling valve 107 is disposed at an outlet of the large chamber 31 of the boom cylinder 3 and is connected to the flow extraction valve 101 and the main valve boom linkage 21, respectively. When the hydraulic excavator is in the non-boom-down working condition, the main valve boom train 21 is in the neutral position, and the anti-settling valve 107 is locked, and at this time, the boom is locked, so that the boom is prevented from falling down due to the dead weight.

It will be appreciated that the large chamber 31 of the boom cylinder 3, the anti-settling valve 107 and the main valve boom linkage 21 form a fourth oil return branch, and that hydraulic oil in the large chamber 31 of the boom cylinder 3 may be returned to the tank 10 via the anti-settling valve 107 and the main valve boom linkage 21.

When the anti-settling valve 107 is opened, the hydraulic oil in the large chamber 31 of the boom cylinder 3 flows into each oil return branch (first oil return branch, second oil return branch, third oil return branch, or fourth oil return branch) via the anti-settling valve 107.

In this embodiment, the specific structure of the anti-settling valve 107 is not limited, as long as the anti-settling valve 107 allows the flow to pass when opened. The anti-settling valve 107 is opened in response to receiving the boom down pilot signal.

When the hydraulic excavator is in the energy-saving mode, the hydraulic excavator may have a non-boom lowering operation, a supporting operation, and a boom excavating operation in addition to the boom lowering operation, the boom idle lowering operation, and the first accumulator 102 full load operation. When the hydraulic excavator is in a supporting vehicle or movable arm excavating working condition, the working device of the hydraulic excavator is influenced by the gravity or excavating resistance of the whole machine, the pressure of the large cavity 31 of the movable arm oil cylinder 3 is lower, for example, the pressure read by the second pressure reading device 105 is lower than a second set value, at the moment, the controllable regeneration valve 106 is closed, the main valve movable arm link 21 is opened, the main pump 1 of the hydraulic excavator provides hydraulic oil, and the hydraulic oil passes through the main valve movable arm link 21 to the small cavity 32 of the movable arm oil cylinder 3, so that the small cavity 32 of the movable arm oil cylinder 3 builds higher pressure, overcomes the gravity or excavating resistance of the whole machine, and realizes supporting vehicle or movable arm excavating; in this process, the oil return passage of the main valve boom linkage 21 is opened, and the flow of the boom large chamber 31 returns to the oil tank 10 through the oil return passage.

It will be appreciated that the main valve train 21 has three operating positions: the device comprises a movable arm descending position, a movable arm ascending position and a middle position, wherein the movable arm descending position and the movable arm ascending position at least comprise an oil inlet path and an oil return path, and the middle position at least comprises an unloading path.

The boom raising function and implementation are the same as those of conventional boom raising in the prior art, and are not repeated here.

Referring to fig. 3, considering the specific implementation of the swing energy recovery device 200, in some embodiments, the swing energy recovery device 200 includes a flow recovery valve 201 and a second accumulator 202, the flow recovery valve 201 being connected to the a-chamber 41 and the B-chamber 42 of the swing motor 4, respectively; the second accumulator 202 is connected to the flow recovery valve 201; when the swing motor 4 is started and the pressure of the a chamber 41 or the B chamber 42 of the swing motor 4 is greater than the third set value, the flow rate recovery valve 201 is opened to allow the surplus hydraulic oil of the a chamber 41 or the B chamber 42 of the swing motor 4 to flow into the second accumulator 202.

That is, the a chamber 41 or the B chamber 42 of the swing motor 4, the flow rate recovery valve 201, and the second accumulator 202 form a swing energy recovery oil path, when the swing motor 4 is started, the rotation speed of the swing motor 4 is low, and the required flow rate of hydraulic oil is small, at this time, the flow rate of hydraulic oil output from the main pump 1 of the hydraulic excavator is more than the required amount of oil for the swing of the swing motor 4, so that the pressure in the swing motor 4A chamber 41 or the B chamber 42 is increased, and when the pressure in the swing motor 4A chamber 41 or the B chamber 42 is more than the third set value, the flow rate recovery valve 201 is opened, so that the surplus hydraulic oil in the swing motor 4A chamber 41 or the B chamber 42 flows to the second accumulator 202, and the energy at the time of the swing start of the swing motor 4 is stored by the second accumulator 202, so that the swing start overflow is prevented.

The specific structure of the flow recovery valve 201 is not limited in this embodiment, as long as the flow recovery valve 201 allows the flow to pass when opened. The opening condition of the flow recovery valve 201 is: the pressure in either one of the rotary motor 4A chamber 41 and the B chamber 42 exceeds a third set value.

Further, with continued reference to FIG. 3, in some embodiments, the hydraulic excavator energy conservation system further includes a hydraulic lock 203, the hydraulic lock 203 being disposed between the swing motor 4 and the main valve swing link 22 of the hydraulic excavator; when the swing motor 4 is braked, the hydraulic lock 203 is closed; when the swing motor 4 is braked and the pressure of the a chamber 41 or the B chamber 42 of the swing motor 4 is greater than the third set value, the flow rate recovery valve 201 is opened so that the surplus hydraulic oil of the a chamber 41 or the B chamber 42 of the swing motor 4 flows into the second accumulator 202.

That is, when the swing motor 4 is turned and braked, the swing motor 4 is not immediately stopped due to the inertia due to the large mass, moment of inertia and moment of inertia of the swing platform of the hydraulic excavator and the working device of the hydraulic excavator, but continues to swing by a certain angle in the original motion state; at this time, since the main circuit from the main pump 1 to the main valve swing link 22 of the hydraulic excavator to the swing motor 4 is not supplied with oil, the main circuit pressure is smaller than the opening pressure of the hydraulic lock 203, so that the hydraulic lock 203 is closed, the swing motor 4A chamber 41 or the B chamber 42 forms a locking chamber, a relatively high pressure is instantaneously generated, and when the pressure is larger than the third set value, the flow recovery valve 201 is opened, so that the surplus hydraulic oil of the swing motor 4A chamber 41 or the B chamber 42 flows into the second accumulator 202, and the swing braking energy recovery is realized.

The main valve swing link 22 is generally O-shaped and has a neutral locking function. The main valve turning link 22 is an open loop control, the controller is an operator, a semi-open state is usually present at the moment of starting or braking, and the moment is usually serious in energy waste, the hydraulic lock 203 is a pure hydraulic loop closed loop control, the controller is loop pressure, the response is rapid, and the locking is timely.

In addition, in the normal operation mode of the hydraulic excavator, the hydraulic lock 203 is opened in both directions, and the swing motion of the swing motor 4 is completely controlled by the main valve swing link 22, as in the conventional hydraulic excavator in the prior art. In the energy-saving working mode of the hydraulic excavator, when the rotary motor 4 is started and rotates at a constant speed, the hydraulic lock 203 is opened bidirectionally; when the swing motor 4 is braked, the hydraulic lock 203 is closed.

That is, the structure of the hydraulic lock 203 needs to satisfy: the oil inlet and return are opened in two directions under the normal working mode of the hydraulic excavator; in the energy-saving operation mode of the hydraulic excavator, the hydraulic lock 203 is opened bidirectionally if and only if the pressure of the loop of the main valve swing link 22 to the hydraulic lock 203 is greater than the opening pressure of the hydraulic lock 203; when the loop pressure from the main valve swivel 22 to the hydraulic lock 203 is smaller than the opening pressure of the hydraulic lock 203 in the energy-saving operation mode of the hydraulic excavator, only the oil inlet path of the hydraulic lock 203 is opened, and the oil return path of the hydraulic lock 203 is closed.

It will be appreciated that when the swing motor 4 is rotated at a constant speed, the pressure in the swing motor 4 chamber is less than the third set point, the flow recovery valve 201 is closed, and all flow in the swing motor 4 chamber is supplied for swing. At this time, the circuit from the main valve swing link 22 to the swing motor 4 builds up a higher pressure, which is greater than the opening pressure of the hydraulic lock 203, the hydraulic lock 203 is opened, and the return oil from the swing motor 4 flows to the oil tank 10 through the hydraulic lock 203 and the main valve swing link 22.

Further, with continued reference to fig. 3, in some embodiments, a back pressure valve 204 is disposed between the main valve swing link 22 of the hydraulic excavator and the oil tank 10 of the hydraulic excavator, and oil supplementing check valves 205 are disposed between the main valve swing link 22 and the a cavity 41 and the B cavity 42 of the swing motor 4 respectively; when the pressure of the a chamber 41 or the B chamber 42 is lower than the set pressure of the back pressure valve 204, the hydraulic oil of the hydraulic excavator main pump 1 supplements the a chamber 41 or the B chamber 42 with oil via the main valve swing link 22 and the oil supplementing check valve 205.

That is, an oil-replenishing oil path is formed between the main valve rotary union 22, the oil-replenishing one-way valve 205 and the rotary motor 4, and when the pressure of the a cavity 41 or the B cavity 42 of the rotary motor 4 is lower than the set pressure of the back pressure valve 204, the hydraulic oil between the main valve rotary union 22 and the back pressure valve 204 flows to the a cavity 41 or the B cavity 42 through the oil-replenishing one-way valve 205 to replenish oil, thereby preventing the a cavity 41 or the B cavity 42 from being empty.

Further, with continued reference to fig. 3, in some embodiments, the a-chamber 41 and the B-chamber 42 of the swing motor 4 are each provided with a relief valve 206. That is, when the pressure in the a chamber 41 or the B chamber 42 of the swing motor 4 is greater than the set pressure of the relief valve 206, the relief valve 206 is opened, so that the hydraulic oil in the a chamber 41 or the B chamber 42 flows to the tank 10 through the relief valve 206, and the system pressure is not greater than the relief pressure.

It should be noted that, in the embodiment of the present invention, the first accumulator 102 and the second accumulator 202 may be the same accumulator 6.

Referring to fig. 4, in some embodiments, the hydraulic excavator energy saving system further includes a function selection valve 7, wherein the function selection valve 7 is connected to the boom energy recovery device 100 and the swing energy recovery device 200, respectively, and is connected to the energy storage motor 8, the preset work device actuator circuit 115, the heat dissipation motor 9, and the power generation device 12 of the hydraulic excavator, respectively, for distributing the energy recovered by the boom energy recovery device 100 and the swing energy recovery device 200 to the energy storage motor 8, the preset work device actuator circuit 115, the heat dissipation motor 9, and/or the power generation device 12.

That is, the hydraulic excavator energy saving system provided in this embodiment further has a recovery energy release function to allocate the energy recovered by the boom energy recovery device 100 and the swing energy recovery device 200 to the energy storage motor 8, the preset work device actuator loop 115, the heat dissipation motor 9 and/or the power generation device 12 through the function selection valve 7, so as to implement the actions of the energy storage motor 8, the preset work device actuator loop 115, the heat dissipation motor 9 and/or the power generation device 12, thereby achieving the purpose of recovering energy for reuse.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by a difference from other embodiments, and identical and similar parts between the embodiments are referred to each other.

The energy-saving system of the hydraulic excavator provided by the invention is described in detail above. The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present invention and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.

Claims (10)

1. An energy-saving system of a hydraulic excavator comprises a movable arm oil cylinder (3) and a rotary motor (4), and is characterized by further comprising at least one of a movable arm energy recovery device (100) and a rotary energy recovery device (200);

the movable arm energy recovery device (100) is connected with a large cavity (31) of the movable arm oil cylinder (3) and is used for recovering energy when a movable arm of the hydraulic excavator descends;

the swing energy recovery device (200) is connected to the chamber of the swing motor (4) for recovering at least one of swing start energy and swing brake energy.

2. The hydraulic excavator energy conservation system of claim 1 wherein the boom energy recovery device (100) comprises:

a flow extraction valve (101) connected to the large chamber (31);

a first accumulator (102) connected to the flow extraction valve (101);

when the movable arm of the hydraulic excavator descends, the flow extraction valve (101) is opened to enable excessive hydraulic oil in the large cavity (31) to flow into the first energy accumulator (102).

3. The hydraulic excavator energy conservation system of claim 2 further comprising:

a flow saturation valve (103) connected between the flow extraction valve (101) and a tank (10) of the hydraulic excavator;

a first pressure reading device (104) provided at the outlet of the flow extraction valve (101);

when the hydraulic excavator arm descends and the pressure of the first pressure reading device (104) exceeds a first set value, the flow saturation valve (103) is opened so that excess hydraulic oil in the large chamber (31) flows into the oil tank (10) through the flow extraction valve (101) and the flow saturation valve (103).

4. The hydraulic excavator energy saving system according to claim 2, characterized in that a controllable regeneration valve (106) is connected between the large chamber (31) and the small chamber (32) of the boom cylinder (3);

when the hydraulic excavator boom is lowered, the controllable regeneration valve (106) opens.

5. The hydraulic excavator energy saving system according to claim 2, characterized in that the outlet of the large chamber (31) is provided with an anti-sedimentation valve (107), the anti-sedimentation valve (107) is connected with a main valve boom linkage (21) of the hydraulic excavator, and the flow extraction valve (101) is connected with the anti-sedimentation valve (107).

6. The hydraulic excavator energy saving system according to claim 5, wherein the opening degree of the flow extraction valve (101) and the main valve boom train (21) are both adjustable.

7. The hydraulic excavator energy conservation system of any one of claims 1 to 6 wherein the swing energy recovery device (200) comprises:

a flow recovery valve (201) connected to the A chamber (41) and the B chamber (42) of the swing motor (4), respectively;

a second accumulator (202) connected to the flow recovery valve (201);

when the rotary motor (4) is started and the pressure of the A cavity (41) or the B cavity (42) is larger than a third set value, the flow recovery valve (201) is opened so that redundant hydraulic oil of the A cavity (41) or the B cavity (42) flows into the second energy accumulator (202).

8. The hydraulic shovel energy conservation system according to claim 7, further comprising:

a hydraulic lock (203) provided between the swing motor (4) and a main valve swing link (22) of the hydraulic excavator; -when the swing motor (4) is braked, the hydraulic lock (203) is closed; when the rotary motor (4) is braked and the pressure of the A cavity (41) or the B cavity (42) is larger than the third set value, the flow recovery valve (201) is opened, so that redundant hydraulic oil of the A cavity (41) or the B cavity (42) flows into the second energy accumulator (202).

9. The hydraulic excavator energy saving system according to claim 7, characterized in that a back pressure valve (204) is arranged between a main valve rotary union (22) of the hydraulic excavator and an oil tank (10) of the hydraulic excavator, and oil supplementing one-way valves (205) are respectively arranged between an A cavity (41) and a B cavity (42) of the main valve rotary union (22) of the rotary motor (4);

when the pressure of the A cavity (41) or the B cavity (42) is lower than the set pressure of the back pressure valve (204), hydraulic oil of a main pump (1) of the hydraulic excavator supplements oil to the A cavity (41) or the B cavity (42) through the main valve rotary union (22) and the oil supplementing one-way valve (205).

10. The hydraulic shovel energy conservation system according to any one of claims 1 to 6, further comprising:

the function selection valve (7) is respectively connected with the movable arm energy recovery device (100) and the rotary energy recovery device (200), and is respectively connected with an energy storage motor (8), a preset working device actuator loop (5), a heat dissipation motor (9) and a power generation device (12) of the hydraulic excavator, and is used for distributing energy recovered by the movable arm energy recovery device (100) and the rotary energy recovery device (200) to the energy storage motor (8), the preset working device actuator loops (11) (5), the heat dissipation motor (9) and/or the power generation device (12).