Gravity potential energy recovery hydraulic system and excavator

Abstract

The invention discloses a gravity potential energy recovery hydraulic system and an excavator, wherein the gravity potential energy recovery hydraulic system comprises: an oil tank; a hydraulic cylinder, wherein when pressure oil is introduced into a first oil chamber, a weight is lifted, and when pressure oil is introduced into a second oil chamber, the weight is lowered; a hydraulic pump; an energy-saving valve, comprising a first oil port connected to the second oil chamber, a second oil port connected to the oil tank, a hydraulic control end is connected to an energy-saving pipeline between the first oil port and the second oil chamber, wherein in a first valve position, the first oil port and the second oil port are disconnected, and in a second valve position, the first oil port and the second oil port are connected through a throttle hole, and in a third valve position, the first oil port and the second oil port are connected; a reversing valve, comprising a third oil port connected to the first oil chamber, a fourth oil port connected to the second oil chamber, a fifth oil port connected to the oil tank, a sixth oil port connected to the first oil port, and a seventh oil port connected to the hydraulic pump, wherein in the fifth valve position, the third oil port is connected to the sixth oil port and the fourth oil port is connected to the seventh oil port.

Description

Technical Field

[0001] The invention relates to the technical field of energy-saving for engineering machinery, and in particular to a gravity potential energy recovery hydraulic system and an excavator. Background Art

[0002] In construction machinery, hydraulic cylinders are often used to control the lifting, lowering, upward swinging and downward swinging of some parts, and some of these parts are heavy objects with large mass. The center of gravity of heavy objects drops during the process of moving or swinging down, and the gravitational potential energy is greatly reduced. The recovery of the gravitational potential energy of some heavy objects during the descent process is of great significance for energy saving. For example, the basic actions of an excavator include the swinging up and down of the boom, the swinging up and down of the dipper arm, the inward and outward swinging of the bucket, etc. Among them, the mass of the boom and the dipper arm is large, the number of operations of the dipper arm is large, and the frequency of swinging down is high. It is worth studying the recovery of the gravitational potential energy of the dipper arm during the swinging down process. Summary of the invention

[0003] The object of the present invention is to provide a gravitational potential energy recovery hydraulic system which can recover the gravitational potential energy of a descending heavy object.

[0004] The first aspect of the present invention discloses a gravity potential energy recovery hydraulic system for lifting and lowering a heavy object, comprising:

[0005] tank;

[0006] A hydraulic cylinder, used to connect with the weight, comprising a piston rod, a cylinder barrel, and a first oil chamber and a second oil chamber formed between the piston rod and the cylinder barrel. When the first oil chamber is fed with pressurized oil, the hydraulic cylinder drives the weight to be lifted, and when the second oil chamber is fed with pressurized oil, the weight is lowered;

[0007] A hydraulic pump connected to the oil tank and used to pump pressure oil to the hydraulic cylinder;

[0008] An energy-saving valve, comprising a first oil port connected to the second oil chamber, a second oil port connected to the oil tank, and a hydraulic control end and a spring end at both ends thereof for controlling the valve position of the energy-saving valve, the hydraulic control end being communicated with an energy-saving pipeline between the first oil port and the second oil chamber, the energy-saving valve having a first valve position, a second valve position and a third valve position, in the first valve position, the first oil port and the second oil port are disconnected, in the second valve position, the first oil port and the second oil port are connected via a throttle hole, in the third valve position, the first oil port and the second oil port are communicated, when the oil pressure of the hydraulic control end is less than the first pressure, the energy-saving valve is in the first valve position, when the oil pressure of the hydraulic control end is greater than the first pressure and less than the second pressure, the energy-saving valve is in the second valve position, and when the oil pressure of the hydraulic control end is greater than the second pressure, the energy-saving valve is in the third valve position;

[0009] A reversing valve having a third oil port connected to the first oil chamber, a fourth oil port connected to the second oil chamber, a fifth oil port connected to the oil tank, a sixth oil port connected to the first oil port and a seventh oil port connected to the hydraulic pump, the reversing valve having a fourth valve position and a fifth valve position, in the fourth valve position, the third oil port is connected to the seventh oil port and the fourth oil port is connected to the fifth oil port, in the fifth valve position, the third oil port is connected to the sixth oil port and the fourth oil port is connected to the seventh oil port.

[0010] In some embodiments, a one-way valve is further included, which is arranged between the first oil port and the connection point between the hydraulic control end and the energy-saving pipeline, and the opening of the one-way valve faces the connection point between the hydraulic control end and the energy-saving pipeline.

[0011] In some embodiments, the opening pressure of the opening of the one-way valve is adjustable.

[0012] In some embodiments, the reversing valve further has a sixth valve position, in which the third oil port, the fourth oil port, the fifth oil port and the sixth oil port are disconnected.

[0013] In some embodiments, the piston rod is connected to the weight, the first oil chamber is a rod chamber, and the second oil chamber is a rodless chamber.

[0014] The second aspect of the present invention discloses an excavator, comprising a boom and any one of the gravity potential energy recovery hydraulic systems described above, wherein the piston rod is connected to the boom, and when the reversing valve is switched to the fifth valve position, the hydraulic pump pumps pressure oil into the second oil chamber, and the boom swings down. In a first time period from when the boom starts to swing down to time t1, the energy-saving valve is in a first valve position, in a second time period from time t1 to time t2, the energy-saving valve is in a second valve position, and in a third time period greater than time t2, the energy-saving valve is in a third valve position, wherein t2 is greater than t1.

[0015] Based on the gravity potential energy recovery hydraulic system provided by the present invention, an energy-saving valve with multiple valve positions and a hydraulic control end is set to be connected between the hydraulic cylinder and the oil tank. When the valve position of the switching reversing valve is switched to pump pressure oil into the second oil chamber to make the heavy object descend, the heavy object drives the piston rod or cylinder connected thereto to move in the initial stage, so that the first oil chamber is reduced, the oil pressure in the second oil chamber is low, and the pressure oil formed in the first oil chamber flows completely into the second oil chamber through the energy-saving valve in the first valve position, so that the second oil chamber can quickly enter the oil, and the gravity potential energy of the heavy object is recovered. After a period of time, after the oil pressure in the second oil chamber increases, the energy-saving valve switches to the second valve position, and the throttle hole is used to partially flow the pressure oil flowing out of the first oil chamber to the oil tank, and partially flows back to the second oil chamber for recovery. In the final stage, the oil pressure in the second oil chamber is high, the energy-saving valve switches to the third valve position, and the hydraulic oil in the first oil chamber flows out to the oil tank. The gravity potential energy recovery hydraulic system can reasonably and coordinately recover the gravity potential energy when the heavy object descends according to the oil pressure in the second oil chamber.

[0016] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 Schematic diagram of the hydraulic principle of the gravity potential energy recovery hydraulic system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0021] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0022] like Figure 1 As shown, the gravity potential energy recovery hydraulic system of this embodiment is used to lift and lower heavy objects. Lifting and lowering heavy objects means that the center of gravity of the heavy object rises or falls, and the gravity potential energy of the heavy object is increased or decreased. The lifting and lowering of the heavy object can be carried out by moving or by swinging, that is, the heavy object can be lifted and lowered by moving, or lifted or lowered by swinging.

[0023] like Figure 1 As shown, the gravity potential energy recovery hydraulic system includes an oil tank 1, a hydraulic cylinder 4, a hydraulic pump 2, an energy-saving valve 3 and a reversing valve 5.

[0024] The hydraulic cylinder 4 is used to connect with the weight. The hydraulic cylinder 4 includes a piston rod 42, a cylinder barrel 41, and a first oil chamber 43 and a second oil chamber 44 formed between the piston rod 42 and the cylinder barrel 41. When the first oil chamber 43 is fed with pressurized oil, the hydraulic cylinder 4 drives the weight to rise, and when the second oil chamber 44 is fed with pressurized oil, the weight falls. That is, the hydraulic cylinder 4 can be connected with the weight through the piston rod 42, or through the cylinder barrel 41. The piston rod 42 can be connected with the weight through the piston rod 42. Figure 1 The single-rod piston rod is shown, and one of the corresponding first oil chamber 43 and the second oil chamber 44 is a rod chamber, and the other is a rodless chamber. In some embodiments not shown in the figure, the piston rod 42 can also be a double-rod piston rod, and the corresponding first oil chamber 43 and the second oil chamber 44 are both rodless chambers. When the first oil chamber 43 is fed with pressure oil, the pressure oil drives the piston rod 42 and the cylinder barrel 41 to produce relative movement, thereby driving the weight connected to the piston rod 42 or the cylinder barrel 41 to lift. When the second oil chamber 44 is fed with pressure oil, at the beginning stage, the oil discharge oil circuit of the first oil chamber 43 is connected, and the weight drives the cylinder barrel 41 or the piston rod 42 connected thereto to move relative to the piston rod 42 or the cylinder barrel 41, the first oil chamber 43 is reduced, and the hydraulic oil flows out. The reversing valve is used to switch the valve position to control the pressure oil pumped by the hydraulic pump 2 to pass into the second oil chamber 44 or into the first oil chamber 43.

[0025] The hydraulic pump 2 is connected to the oil tank 1 , and is used to provide pressurized oil for the action of the hydraulic cylinder 4 .

[0026] The energy-saving valve 3 includes a first oil port a connected to the second oil chamber 44, a second oil port b connected to the oil tank 1, and a hydraulic control end and a spring end at both ends thereof for controlling the valve position of the energy-saving valve 3. The hydraulic control end of the energy-saving valve 3 is connected to the energy-saving pipeline 8 between the first oil port a and the second oil chamber 44. The energy-saving valve 3 has a first valve position, a second valve position, and a third valve position. In the first valve position, the first oil port a and the second oil port b are disconnected, that is, the first oil port a and the second oil port b are not connected at this time. In the second valve position, the first oil port a and the second oil port b are connected through a throttle hole, that is, at this time, the first oil port a and the second oil port b are connected, but there is a pressure loss between the first oil port a and the second oil port b. In the third valve position, the first oil port a and the second oil port b are connected, that is, at this time, there is no pressure loss or a small pressure loss between the first oil port a and the second oil port b. The switching of the valve position of the energy-saving valve 3 is controlled by its hydraulic control end and the spring end. When the pressure of the hydraulic control end is greater than the pressure of the spring end, the valve core of the energy-saving valve 3 moves. When the valve core moves a certain displacement, the valve position of the energy-saving valve 3 switches. When the oil pressure of the hydraulic control end is less than the first pressure, the energy-saving valve 3 is in the first valve position. When the oil pressure of the hydraulic control end is greater than the first pressure and less than the second pressure, the energy-saving valve 3 is in the second valve position. When the oil pressure of the hydraulic control end is greater than the second pressure, the energy-saving valve 3 is in the third valve position. The magnitude of the first pressure and the second pressure is determined by the stiffness and deformation of the spring at the spring end.

[0027] The reversing valve 5 has a third oil port c connected to the first oil chamber 43, a fourth oil port d connected to the second oil chamber 44, a fifth oil port e connected to the oil tank 1, a sixth oil port f connected to the first oil port a, and a seventh oil port g connected to the hydraulic pump 2. The reversing valve 5 has a fourth valve position and a fifth valve position. In the fourth valve position, the third oil port c is connected to the seventh oil port g and the fourth oil port d is connected to the fifth oil port e. At this time, the pressure oil pumped out by the hydraulic pump 2 enters the third oil port c through the seventh oil port g and enters the first oil chamber 43 through the third oil port c. The hydraulic oil of the second oil chamber 44 enters the fifth oil port e through the fourth oil port d and enters the oil tank 1 through the fifth oil port e. The hydraulic cylinder 4 drives the heavy object to lift.

[0028] When the reversing valve 5 is switched to the fifth valve position, its third oil port c is connected with the sixth oil port f and the fourth oil port d is connected with the seventh oil port g. At this time, the pressure oil pumped out by the hydraulic pump 2 enters the fourth oil port d through the seventh oil port g, and enters the second oil chamber 44 through the fourth oil port d. At this time, the heavy object enters the descending mode. At the beginning of the descent, the heavy object drives the first oil chamber 43 to shrink and generate pressure oil. The pressure oil generated by the first oil chamber 43 enters the sixth oil port f through the third oil port c, and then enters the first oil port a through the sixth oil port f. Since the pressure of the pressure oil in the second oil chamber 44 is relatively small at the beginning, the pressure of the hydraulic oil in the energy-saving pipeline 8 is relatively small, which is less than the first pressure. The energy-saving valve 3 is in the first valve position, the first oil port a and the second oil port b are not connected, and the hydraulic oil in the first oil port a flows into the second oil chamber 44. That is, at this time, all the pressure oil discharged from the first oil chamber 43 enters the second oil chamber 44, the gravity potential energy of the descending heavy object is recovered, and the pressure oil in the second oil chamber 44 can be replenished more quickly, which also helps to prevent the second oil chamber 44 from "sucking air". After dropping for a period of time, the oil pressure in the second oil chamber 44 increases. When the oil pressure in the energy-saving pipeline 8 is greater than the first pressure, the energy-saving valve 3 switches to the second valve position. The pressure oil discharged from the first oil chamber 43 enters the first oil port a, and then part of it enters the second oil port b through the throttle hole, and then returns to the oil tank from the second oil port b, and the other part enters the energy-saving pipeline 8 and enters the second oil chamber 44. At this time, the pressure of the pressure oil discharged from the first oil chamber 43 is closer to the pressure of the pressure oil in the second oil chamber 44. The first oil port a and the second oil port b connected by the throttle hole can reasonably distribute the pressure oil discharged from the first oil chamber 43, with one part entering the second oil chamber for recovery and the other part entering the oil tank 1 for discharge, so as to save energy reasonably and effectively. When the weight continues to descend for a period of time, the oil pressure in the second oil chamber 44 continues to increase. When the oil pressure in the energy-saving pipeline 8 is greater than the second pressure, the energy-saving valve 3 switches to the third valve position, and the pressure oil discharged from the first oil chamber 43 enters the first oil port a and then all enters the second oil port b. At this time, in order to allow the weight to descend at a reasonable speed, if the hydraulic oil discharged from the first oil chamber 43 continues to enter the second oil chamber 44, it will not be energy-efficient. At this time, the oil pressure in the first oil chamber 43 is directly discharged into the oil tank 1.

[0029] The gravity potential energy recovery hydraulic system of this embodiment is connected between the hydraulic cylinder 4 and the oil tank 1 by setting an energy-saving valve 3 with multiple valve positions and hydraulic control ends. When the valve position of the switching valve 5 is switched to pump pressure oil into the second oil chamber 44 to lower the weight, the weight drives the piston rod 42 or the cylinder 41 connected thereto to move in the initial stage, so that the first oil chamber 43 is reduced, and the oil pressure in the second oil chamber 44 is low. The pressure oil formed in the first oil chamber 43 flows completely into the second oil chamber 44 through the energy-saving valve 3 in the first valve position, so that the second oil chamber 44 can quickly fill with oil, and the gravity potential energy of the weight is recovered. After a period of time, after the oil pressure in the second oil chamber 44 increases, the energy-saving valve 3 switches to the second valve position, and uses the throttle hole to partially flow the pressure oil flowing out of the first oil chamber 43 to the oil tank 1, and partially flows back to the second oil chamber 44 for recovery. In the final stage, the oil pressure in the second oil chamber 44 is high, the energy-saving valve 3 switches to the third valve position, and the hydraulic oil in the first oil chamber 43 all flows out to the oil tank 1. The gravity potential energy recovery hydraulic system can reasonably and coordinatedly recover the gravity potential energy of the heavy object when it descends according to the oil pressure in the second oil chamber 44 .

[0030] In some embodiments, Figure 1 As shown, the gravity potential energy recovery hydraulic system also includes a one-way valve 7, which is arranged between the first oil port a and the connection point 81 between the hydraulic control end and the energy-saving pipeline 8, and the opening of the one-way valve 7 faces the connection point between the hydraulic control end and the energy-saving pipeline 8. When the heavy object is lowered, the one-way valve 7 can prevent the hydraulic oil in the second oil chamber 44 from flowing back into the first oil chamber 43, thereby improving the energy-saving effect. At the same time, when the energy-saving valve 4 is in the first valve position, before the hydraulic oil discharged from the first oil chamber 43 enters the second oil chamber 44, the one-way valve 7 needs to be opened first, and then enter the second oil chamber 44 through the one-way valve 7, that is, the pressure oil discharged from the first oil chamber 43 needs to be greater than the opening pressure of the one-way valve 7 before it can enter the second oil chamber 44. In some embodiments, the opening pressure of the opening of the one-way valve 7 is adjustable. In some embodiments, the energy-saving valve 3 includes the one-way valve 7, that is, the one-way valve 7 can be integrated into the energy-saving valve 3.

[0031] In some embodiments, the energy-saving valve 3 is a proportional control valve.

[0032] In some embodiments, Figure 1 As shown, the reversing valve 5 also has a sixth valve position, in which the third oil port c, the fourth oil port d, the fifth oil port e and the sixth oil port f are disconnected. At this time, the first oil chamber 43 and the second oil chamber 44 of the hydraulic cylinder are both in a locked state, and the weight remains locked in position.

[0033] In some embodiments, the piston rod 42 is connected to a weight, the first oil chamber 43 is a rod chamber, and the second oil chamber 44 is a rodless chamber.

[0034] In some embodiments, the reversing valve 5 is a hydraulically controlled reversing valve, which includes two hydraulically controlled ends, which are respectively connected to the handle control valve 6, and the two handles of the handle control valve control the valve position of the reversing valve 5. In some embodiments, the reversing valve 5 is a part of a multi-way valve.

[0035] In some embodiments, an excavator is also disclosed, which includes a boom and any of the above-mentioned gravity potential energy recovery hydraulic systems, the piston rod 42 is connected to the boom, and when the reversing valve 5 is switched to the fifth valve position, the hydraulic pump 2 pumps pressure oil to the second oil chamber 44, and the boom swings down. In the first time period from the start of the boom swinging down to time t1, the energy-saving valve 3 is in the first valve position, in the second time period from time t1 to time t2, the energy-saving valve 3 is in the second valve position, and in the third time period greater than time t2, the energy-saving valve 3 is in the third valve position, wherein t2 is greater than t1.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A gravity potential energy recovery hydraulic system for lifting and lowering heavy objects, characterized in that: include: tank; A hydraulic cylinder, used to connect with the weight, comprising a piston rod, a cylinder barrel, and a first oil chamber and a second oil chamber formed between the piston rod and the cylinder barrel. When the first oil chamber is fed with pressurized oil, the hydraulic cylinder drives the weight to be lifted, and when the second oil chamber is fed with pressurized oil, the weight is lowered; A hydraulic pump connected to the oil tank and used to pump pressure oil to the hydraulic cylinder; An energy-saving valve, comprising a first oil port connected to the second oil chamber, a second oil port connected to the oil tank, and a hydraulic control end and a spring end at both ends thereof for controlling the valve position of the energy-saving valve, the hydraulic control end being communicated with an energy-saving pipeline between the first oil port and the second oil chamber, the energy-saving valve having a first valve position, a second valve position and a third valve position, in the first valve position, the first oil port and the second oil port are disconnected, in the second valve position, the first oil port and the second oil port are connected via a throttle hole, in the third valve position, the first oil port and the second oil port are communicated, when the oil pressure of the hydraulic control end is less than the first pressure, the energy-saving valve is in the first valve position, when the oil pressure of the hydraulic control end is greater than the first pressure and less than the second pressure, the energy-saving valve is in the second valve position, and when the oil pressure of the hydraulic control end is greater than the second pressure, the energy-saving valve is in the third valve position; A reversing valve having a third oil port connected to the first oil chamber, a fourth oil port connected to the second oil chamber, a fifth oil port connected to the oil tank, a sixth oil port connected to the first oil port and a seventh oil port connected to the hydraulic pump, the reversing valve having a fourth valve position and a fifth valve position, in the fourth valve position, the third oil port is connected to the seventh oil port and the fourth oil port is connected to the fifth oil port, in the fifth valve position, the third oil port is connected to the sixth oil port and the fourth oil port is connected to the seventh oil port.

2. The gravity potential energy recovery hydraulic system according to claim 1, characterized in that: It also includes a one-way valve, which is arranged between the first oil port and the connection point between the hydraulic control end and the energy-saving pipeline, and the opening of the one-way valve faces the connection point between the hydraulic control end and the energy-saving pipeline.

3. The gravity potential energy recovery hydraulic system according to claim 2, characterized in that: The opening pressure of the opening of the one-way valve is adjustable.

4. The gravity potential energy recovery hydraulic system according to claim 1, characterized in that: The reversing valve further has a sixth valve position, in which the third oil port, the fourth oil port, the fifth oil port and the sixth oil port are disconnected.

5. The gravity potential energy recovery hydraulic system according to claim 1, characterized in that: The piston rod is connected to the weight, the first oil chamber is a rod chamber, and the second oil chamber is a rodless chamber.

6. An excavator, characterized in that: It includes a boom and a gravity potential energy recovery hydraulic system as described in any one of claims 1 to 5, the piston rod being connected to the boom, and when the reversing valve is switched to the fifth valve position, the hydraulic pump pumps pressurized oil into the second oil chamber, and the boom swings down. In a first time period from when the boom starts to swing down to time t1, the energy-saving valve is in the first valve position, in a second time period from time t1 to time t2, the energy-saving valve is in the second valve position, and in a third time period greater than time t2, the energy-saving valve is in the third valve position, wherein t2 is greater than t1.

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