Energy recovery device

Abstract

The present invention relates to an energy recovery device, and more particularly to an energy recovery device for construction machinery and a construction machine including the same. According to such a present invention, it includes a pressure accumulator assembly, can recover the energy discarded during boom down and utilize it, can operate in various operation modes, and also has the advantage of being easily installed or removed on existing construction machinery.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application Nos. 10-2022-0065454 and 10-2022-0118094 filed on May 27, 2022 and September 19, 2022, respectively, and all contents disclosed in the documents of the Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an energy recovery device, and more particularly, to an energy recovery device for construction machinery and a construction machinery including the same.

Background Art

[0003] Forklifts and excavators are construction machines generally used for digging or cutting the ground and are widely used at construction sites and various industrial sites. Such forklifts include a boom whose end can move along a curved trajectory, and many tools such as buckets can be attached to the end of the boom.

[0004] A hydraulic cylinder is connected to the boom, and the hydraulic cylinder drives the boom while moving up and down. The hydraulic cylinder moves up and down by the oil flow of the hydraulic system. The forklift includes a power means such as an engine. The engine can provide the flow power of the oil flow in the hydraulic system and the power for the movement of the forklift.

[0005] Generally, since a forklift is very heavy, the fuel consumption due to movement is very high. Also, since the self-weight of the boom is heavy, a lot of fuel is consumed to drive the boom.

[0006] Recently, amid the emergence of environmental problems, various technological developments and research have been carried out in the construction machinery field such as forklifts to improve fuel efficiency. For example, when the boom of a forklift lowers, after recovering the potential energy of the boom, technologies have been proposed to temporarily store this energy and assist in the movement of the forklift or the driving of the boom. However, such conventional technologies have problems of imposing significant restrictions on the working operations and working speed of the boom, reducing work efficiency, and being very difficult to install on existing various forklifts.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Based on the above - mentioned technical background, the present invention provides an energy recovery device for construction machinery that can recover and utilize the energy discarded during boom - down in construction machinery, can operate in various operation modes, and can be easily installed or removed on existing construction machinery, and a construction machinery including the same.

Means for Solving the Problems

[0009] The energy recovery device for construction machinery according to an embodiment of the present invention is a construction machinery energy recovery device provided in a construction machinery including a cylinder that moves up and down by the flow of oil and a boom driven by the cylinder, and includes a bracket, an accumulator, a main pipe, and a valve assembly. The bracket is detachably fastened to the construction machinery. The accumulator is disposed on the bracket and can accumulate oil. The main pipe is disposed on the bracket and connected to the cylinder. The valve assembly is disposed on the bracket and connected to the main pipe. The valve assembly includes a first line, a second line, and an LA valve. The first line is connected to the large chamber of the cylinder. The second line connects between the first line and the accumulator. The LA valve is provided in the second line so that oil can flow only toward the accumulator and can control the flow rate.

[0010] Further, the valve assembly may include a third line connecting between the first line and the accumulator, and an AL valve provided so that oil can flow only toward the first line in the third line and capable of controlling the flow rate.

[0011] Further, the bracket has the main pipe and the valve assembly disposed on the front side facing the boom, a hollow portion formed on the rear side, and a mount for mounting the accumulator can be disposed between the front side and the rear side.

[0012] Further, a boom-up valve for raising the boom and a boom-down valve for lowering the boom are connected to the main control valve of the construction machinery, and the boom-up valve and the boom-down valve can be controlled by an electronic control unit based on an operation signal of a joystick of the construction machinery.

[0013] It further includes a hydraulic motor assembly including a hydraulic motor that forms a rotational force by a fluid. The valve assembly further includes a fourth line connecting between the accumulator and the hydraulic motor, and an AM valve provided to enable oil flow control in the fourth line at all times. The hydraulic motor is connected to the shaft of the engine of the construction machine and can provide a rotational force to the shaft.

[0014] Also, the valve assembly can further include a fifth line connected to the small chamber of the cylinder, a sixth line branched from the first line and connected to the fifth line, and an LS valve provided to enable oil flow control in the sixth line.

[0015] Also, the valve assembly can further include a seventh line branched from the first line and connected to the oil tank, and an LT valve provided to enable oil flow control in the seventh line.

[0016] Also, the valve assembly can further include a release valve disposed on the flow path between the accumulator and the oil tank and operating in an on-off manner.

[0017] Also, an externally communicable terminal is separately provided, and the valve assembly can be controlled through an electronic control unit based on the operation signal of the terminal.

[0018] Also, the valve assembly can be controlled in an eco mode or a power mode. The eco mode is a mode that assists the output of the engine of the construction machine using the oil accumulated in the accumulator, and the power mode can be a mode that assists the boom-up of the boom using the oil accumulated in the accumulator.

[0019] A construction machine according to an embodiment of the present invention includes a body, a cylinder, a boom, a bracket, an accumulator, a main pipe, and a valve assembly. The cylinder is connected to the body and moves up and down by the flow of oil. The boom is connected to the body and is driven by the cylinder. The bracket is detachably fastened to the body. The accumulator is disposed on the bracket and can accumulate oil. The main pipe is disposed on the bracket and is connected to the cylinder. The valve assembly is disposed on the bracket and includes a valve assembly connected to the main pipe. The valve assembly includes a first line, a second line, a third line, an LA valve, and an AL valve. The first line is connected to the large chamber of the cylinder. The second line and the third line connect between the first line and the accumulator. The LA valve is provided in the second line so that oil can flow only toward the accumulator and the flow rate can be controlled. The AL valve is provided in the third line so that oil can flow only toward the first line and the flow rate can be controlled.

Advantages of the Invention

[0020] The energy recovery device for a construction machine according to the present invention and the construction machine including the same include an accumulator assembly, can recover the energy discarded during boom down and utilize it, can operate in various operation modes, and also have the effect of being easily installed or removed on an existing construction machine.

Brief Description of the Drawings

[0021]

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Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0022] Since the present invention can be subjected to various conversions and can have various embodiments, specific embodiments will be exemplified and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all conversions, equivalents, and alternatives included in the spirit and technical scope of the present invention. The terms used in the present invention are used only to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as "including" or "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should not be understood that the presence or addition possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof, etc. is excluded in advance. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that the same components in the accompanying drawings are denoted by the same reference numerals as much as possible. In addition, detailed descriptions of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or illustrated schematically.

[0023] Hereinafter, with reference to the accompanying drawings, an energy recovery device for a construction machine according to the present invention and a construction machine including the same will be described in detail.

[0024] FIG. 1 is a conceptual diagram showing an overall aspect of a construction machine according to an embodiment of the present invention, FIG. 2 is a system diagram of a construction machine according to an embodiment of the present invention, FIG. 3 is a plan view of a pressure accumulator assembly according to an embodiment of the present invention, FIG. 4 is a perspective view of a pressure accumulator assembly according to an embodiment of the present invention, FIG. 5 is a plan view showing only a bracket of a pressure accumulator assembly according to an embodiment of the present invention separately cut open, and FIG. 6 is a perspective view of a hydraulic motor assembly according to an embodiment of the present invention.

[0025] Hereinafter, with reference to FIGS. 1 to 6, a construction machine energy recovery device according to an embodiment of the present invention and a construction machine 100 including the same will be described in detail.

[0026] A construction machine 100 according to an embodiment of the present invention includes a body 110, a boom 130, and a cylinder 140. The boom 130 is connected to the body 110. The cylinder 140 is connected to the body 110. The cylinder 140 moves up and down by the flow of oil. The boom 130 can rotate by the up and down movement of the cylinder 140. An engine 120 is disposed inside the body 110. The engine 120 can provide the flow of oil to the cylinder 140. On the other hand, the engine 120 can provide driving force to a driving part (not shown) disposed below the body 110.

[0027] Regarding the operation of the cylinder 140, when examined in more detail, it is as follows. The construction machine 100 can have a cabin 150 on which an operator can board disposed on the body 110, and a joystick 151 capable of controlling the boom-up or boom-down operation of the boom 130 can be disposed on the cabin 150. The construction machine 100 can have a main control valve 160 disposed thereon. A spool 161 can be disposed on the main control valve 160. The cylinder 140 includes a rod 141 that moves up and down and is connected to the boom 130. The rod 141 is disposed between the small chamber 143 and the large chamber 142 of the cylinder 140, and can rise when oil flows into the large chamber 142 and can fall when oil flows into the small chamber 143. When the rod 141 rises, the boom 130 can boom up, and when the rod 141 falls, the boom 130 can boom down.

[0028] The large chamber 142 can be connected by the main control valve 160 and the large chamber line 144, and the small chamber 143 can be connected by the main control valve 160 and the small chamber line 145. By the operation of the spool 161 of the main control valve 160, the flow of oil can be directed towards the small chamber 143 side or the large chamber 142 side. That is, by the operation of the spool 161 of the main control valve 160, the load 141 of the cylinder 140 can be raised or lowered. The engine 120 is provided with a shaft 121, and a main pump 122 can be connected to the shaft 121. The main pump 122 and the spool 161 are connected to the main valve line 162, and oil can flow through the main valve line 162 to the spool 161 and the main control valve 160.

[0029] The spool 161 can be controlled by the boom-up valve 163 and the boom-down valve 164. An auxiliary pump 123 can be connected to the shaft 121 of the engine 120. The auxiliary pump 123 and the spool 161 are connected to the boom-up valve line 165, and the boom-up valve 163 can be arranged on the boom-up valve line 165. The auxiliary pump 123 and the spool 161 are connected to the boom-down valve line 166, and the boom-down valve 164 can be arranged on the boom-down valve line 166. When the boom-up valve 163 opens, the spool 161 moves and oil can flow into the large chamber 142. When the boom-down valve 164 opens, the spool 161 moves and oil can flow into the small chamber 143.

[0030] The construction machine 100 can be equipped with an electronic control unit 170. The joystick 151 can be equipped with a first sensor S1 and a second sensor S2. The first sensor S1 can sense the pressure change during the boom-up operation of the joystick 151 and generate an operation signal, and the second sensor S2 can sense the pressure change during the boom-down operation of the joystick 151 and generate an operation signal. The operation signals generated by the first sensor S1 and the second sensor S2 are transmitted to the electronic control unit 170, and the electronic control unit 170 can control whether to open or close the boom-up valve 163 or the boom-down valve 164 based on such operation signals. On the other hand, the boom-down valve 164 can also be arranged on the large chamber line 144. That is, the boom-down valve 164 can control not only the flow of the boom-down valve line 166 but also the flow of the large chamber line 144. In this case, depending on the situation, when the boom-down operation of the joystick 151 is performed, the electronic control unit 170 can be controlled to close the boom-down valve 164 to block the flow of oil from the large chamber 142 to the main control valve 160.

[0031] The energy recovery device for a construction machine according to an embodiment of the present invention includes a pressure accumulator assembly 200, and the pressure accumulator assembly 200 includes a bracket 210, a pressure accumulator 220, a valve assembly 230, and a main pipe 240. The bracket 210 is detachably fastened to the body 110 of the construction machine 100. The pressure accumulator 220, the valve assembly 230, and the main pipe 240 are arranged on the bracket 210.

[0032] The pressure accumulator 220 can store oil and can discharge the oil pre-stored in the pressure accumulator 220 from the pressure accumulator 220 when necessary. The main pipe 240 is connected to the cylinder 140. The valve assembly 230 is connected to the main pipe 240.

[0033] The valve assembly 230 includes a first line L1, a second line L2, a third line L3, an LA valve LA, and an AL valve AL. The first line L1 is a line connected to the large chamber 142 of the cylinder 140. The first line L1 can be connected to the large chamber line 144. The second line L2 and the third line L3 are lines connecting between the first line L1 and the accumulator 220. The LA valve LA is disposed in the second line L2. The LA valve LA is a valve provided such that oil can flow only from the second line L2 toward the accumulator 220, and is provided such that the flow rate of such flow can be controlled. The AL valve AL is disposed in the third line L3. The AL valve AL is a valve provided such that oil can flow only from the third line L3 toward the first line L1, and is provided such that the flow rate of such flow can be controlled.

[0034] The energy recovery device for a construction machine according to an embodiment of the present invention may further include a hydraulic motor assembly 300. The hydraulic motor assembly 300 includes a hydraulic motor 310. The hydraulic motor 310 is a device that forms a rotational force by a fluid, and can form a rotational force when oil flows into the hydraulic motor 310. The rotation shaft of the hydraulic motor 310 can be connected to the shaft 121 of the engine 120. Thereby, the hydraulic motor 310 can provide a rotational force to the shaft 121. The hydraulic motor assembly 300 can include a pipe through which oil can flow into or out of the hydraulic motor 310, and can also include a pipe connected to the oil tank T.

[0035] The valve assembly 230 can include a fourth line L4 connecting the accumulator 220 and the hydraulic motor 310. The valve assembly 230 can include an AM valve AM provided such that the flow rate of oil can be controlled in the fourth line L4. The oil accumulated in the accumulator 220 flows into the hydraulic motor 310 through the fourth line L4, and the hydraulic motor 310 can be rotated.

[0036] The valve assembly 230 can include a fifth line L5 and a sixth line L6. The fifth line L5 is a line connected to the small chamber 143 of the cylinder 140. The fifth line L5 can be connected to the small chamber line 145. The sixth line L6 is a line branched from the first line L1 and connected to the fifth line L5. An LS valve LS can be arranged in the sixth line L6 so that the oil flow rate can be controlled in the sixth line L6.

[0037] The valve assembly 230 can include a seventh line L7. The seventh line L7 is a line branched from the first line L1 and connected to the oil tank T. An LT valve LT can be arranged in the seventh line L7 so that the oil flow rate can be controlled in the seventh line L7.

[0038] The valve assembly 230 can include a release valve RE. The release valve RE is arranged on the flow path between the accumulator 220 and the oil tank T. The release valve RE operates in an on-off manner.

[0039] Any of the AM valve AM, AL valve AL, LA valve LA, LS valve LS, LT valve LT, release valve RE, etc. of the valve assembly 230 described above can be controlled by the electronic control unit 170.

[0040] Hereinafter, with particular reference to FIGS. 3 to 6, the structures of the accumulator assembly 200 and the hydraulic motor assembly 300 will be discussed in more detail. The accumulator assembly 200 includes a bracket 210, an accumulator 220, a valve assembly 230, and a main pipe 240 as described above.

[0041] The bracket 210 is a part provided on the construction machine 100, and is configured such that the accumulator 220, the valve assembly 230, and the main pipe 240 are arranged. The valve assembly 230 can be respectively opened and closed by the pilot pipe 250. The main pipe 240 is a pipe connected to the cylinder 140. One main pipe 240 is provided, and the first line L1 and the fifth line L5 can be simultaneously formed on the main pipe 240. Or two main pipes 240 are provided, and the first line L1 and the fifth line L5 can be separately formed on each of them. A joint block 241 can be arranged at the tip of the main pipe 240. The large chamber 142 and the small chamber 143 of the cylinder 140 can be connected to the joint block 241.

[0042] The bracket 210 can be formed in a thin plate shape or a plate shape. The bracket 210 can be arranged outside the construction machine 100. The bracket 210 can be provided with a fastening part (not shown) so as to be fastened to the construction machine 100. The fastening part (not shown) can be provided, for example, with a screw hole into which a bolt can be inserted.

[0043] The main pipe 240 and the valve assembly 230 are arranged on the front side of the bracket 210 facing the boom 130, a hollow part 212 is formed on the rear side, and the accumulator 220 can be arranged between the front side and the rear side. A groove part 213 can be formed on the front side of the bracket 210.

[0044] The groove portion 213 can be formed to recess rearward from the front end of the bracket 210. The shape of the groove portion 213 is formed to correspond to the shape of the outer surface of the cab 150 of the construction machine 100, and spatial interference between the cab 150 and the bracket 210 can be minimized. The main pipe 240 and the valve assembly 230 can be arranged at a portion of the bracket 210 where the groove portion 213 is not formed on the front side. That is, the groove portion 213 is formed on either one from the front side of the bracket 210, and the main pipe 240 and the valve assembly 230 can be arranged on the other remaining side. With such a structure of the bracket 210, the portion of the bracket 210 where the main pipe 240 and the valve assembly 230 are arranged can be arranged closer to the boom 130, whereby the lengths of various pipes or lines connected to the cylinder 140 can be minimized, and the flow resistance of oil flow can be minimized.

[0045] A hollow portion 212 can be formed on the rear side of the bracket 210. The engine 120 can be arranged on the rear side of the accumulator assembly 200. The hollow portion 212 can reduce the influence of the heat generated by the engine 120 on the accumulator 220. Also, the hollow portion 212 can reduce the weight of the bracket 210. The hollow portion 212 can be formed not only on the rear side of the bracket 210 but also on the central portion or the front side of the bracket 210. Also, the accumulator 220 can be arranged separated from the rear end portion (the rear side end portion) of the bracket 210. Through this, even when the accumulator assembly 200 is provided on the construction machine 100, it becomes easy to open the engine room for servicing the engine 120, and it can also become easier for an operator to separate and install the accumulator 220. Moreover, it is possible to prevent heat, vibration, etc. generated by the engine 120 from being directly transmitted to the accumulator 220.

[0046] A mount 211 can be arranged between the front side and the rear side of the bracket 210. The mount 211 is configured to mount the accumulator 220. By means of the mount 211, the accumulator 220 can be arranged at a predetermined distance from the upper surface of the bracket 210. Thereby, the separation and installation of the accumulator 220 can be facilitated, and it is possible to prevent the heat and vibration generated by the engine 120 from being directly transmitted to the accumulator 220.

[0047] The bracket 210 can be detachably provided on the construction machine 100. The bracket 210 can be provided in a manner of modifying the exterior or interior of the existing construction machine 100. The specific size and detailed form of the bracket 210 can be partially modified according to the construction machine 100 to which it is provided. With such a configuration of the bracket 210, the energy recovery device according to the present invention can be easily and simply provided on various existing construction machines 100.

[0048] The hydraulic motor 310 of the hydraulic motor assembly 300 can be provided in the engine room where the engine 120 is arranged in the construction machine 100. For this purpose, the hydraulic motor 310 can be provided with a fastening part (not shown) that can be fastened to the engine room. In addition, pipes through which oil can flow in or out, pipes connected to the oil tank T, etc. can be provided so as to be connectable to the corresponding pipes in the existing construction machine 100.

[0049] The energy recovery device for construction machinery according to an embodiment of the present invention can be controlled by a terminal 400. Specifically, a terminal communicable with an electronic control unit 170 is provided outside the construction machinery 100, and a valve assembly 230 of the accumulator assembly 200 can be controlled through the electronic control unit 170 based on an operation signal of the terminal 400. The terminal 400 can include an input means for inputting a control command and an output means such as a display for displaying an operating state of the accumulator assembly 200. For example, the terminal 400 can be a smartphone. The terminal 400 can communicate wirelessly with the electronic control unit 170 using a Bluetooth communication method, and the communication method of the terminal 400 is not limited thereto.

[0050] The energy recovery device for construction machinery according to an embodiment of the present invention can be controlled in an eco mode or a power mode, and in some cases, can also be controlled in a release mode. Such setting, changing, and canceling of many modes can be performed by the electronic control unit 170 and the terminal 400. The various modes described above will be described in detail below.

[0051] FIG. 7 is a system diagram showing oil flow when a boom is lowered in a construction machine according to an embodiment of the present invention.

[0052] Hereinafter, with reference to FIG. 7, the oil flow when the boom 130 is lowered will be described in detail. When the boom 130 is lowered, the load 141 of the cylinder 140 descends, and the oil inside the large chamber 142 is discharged through the first line L1. At this time, the boom-down valve 164 is closed, and the oil does not flow to the main control valve 160 side and can be discharged to the first line L1. The oil flowing in the first line L1 can flow into the accumulator 220 through the second line L2, whereby the oil can be stored inside the accumulator 220. Through such a process, the potential energy of the boom 130 can be stored in the accumulator 220.

[0053] When the LS valve LS is provided, when the LS valve LS is opened, a part of the oil flowing in the first line L1 can flow into the small chamber 143 of the cylinder 140 through the sixth line L6 and the fifth line L5. Such oil flow can be carried out simultaneously during the process of accumulating oil in the accumulator 220. That is, a part of the flow in the first line L1 flows into the accumulator 220, and the remaining part can flow into the small chamber 143. In this case, the size of the accumulator 220 can be made compact. Also, since oil flows into the small chamber 143, the boom-down speed of the boom 130 can be increased. On the other hand, the eighth line L8 can be further connected to the fifth line L5 and the sixth line L6. The eighth line L8 can be connected to the oil tank T. Through the eighth line L8, the oil that has passed through the LS valve LS can also flow into the oil tank T.

[0054] When the LT valve LT is provided, when the LT valve LT is opened, a part of the oil flowing in the first line L1 can flow into the oil tank T through the seventh line L7. When the accumulator 220 is filled with oil, the boom-down of the boom 130 may not operate further. In this case, the oil can be bypassed to the oil tank T to make the boom-down of the boom 130 smooth. The fifth sensor S5 can be arranged in front of the second line L2 and the accumulator 220. The fifth sensor S5 can measure the pressure in front of the accumulator 220. The fifth sensor S5 can measure whether the accumulator 220 is filled with oil.

[0055] On the other hand, if the boom 130 hits the ground while the boom-down of the boom 130 is in progress and a large force is required for the boom-down of the boom 130, the accumulator can be temporarily interrupted. When the boom 130 hits the ground, the third sensor S3 can be arranged on the first line L1 and the fourth sensor S4 can be arranged on the fifth line L5. However, the third sensor S3 and the fourth sensor S4 constantly measure the hydraulic pressure and transmit the measured values to the electronic control unit 170, and the electronic control unit 170 can determine whether the boom 130 has hit the ground through such measured values. If the electronic control unit 170 determines that the boom 130 has hit the ground, the electronic control unit 170 can close the LA valve LA and temporarily stop the oil from being accumulated in the accumulator 220. In addition, the electronic control unit 170 can close both the LA valve LA and the LT valve LT, open the LS valve LS, and control so that all the oil discharged from the large chamber 142 flows into the small chamber 143.

[0056] The oil flow in the case of the boom-down described above can be constantly performed regardless of the operating mode such as the echo mode and the power mode.

[0057] FIG. 8 is a system diagram showing the oil flow when the boom is raised in the echo mode in a construction machine according to an embodiment of the present invention.

[0058] Hereinafter, with further reference to FIG. 8, the energy recovery device for a construction machine according to an embodiment of the present invention and the boom-up operation in the echo mode of the construction machine 100 including the same will be described in detail. The echo mode is a mode that assists the output of the engine 120 by using the oil accumulated in the accumulator 220.

[0059] When the boom 130 booms up in the echo mode, the AM valve AM arranged on the fourth line L4 is opened. At this time, the AL valve AL arranged on the third line L3 is closed. The oil accumulated in the accumulator 220 flows into the hydraulic motor 310 of the hydraulic motor assembly 300 through the fourth line L4. The rotating shaft of the hydraulic motor 310 of the hydraulic motor assembly 300 is rotated by the inflowing oil, and the rotational force of the rotating shaft of the hydraulic motor 310 generated in this process is provided to the shaft 121 of the engine 120. In the echo mode, since the rotational force of the hydraulic motor 310 can assist the output of the engine 120 shaft 121, the fuel consumption of the engine 120 can increase. On the other hand, the oil flowing into the hydraulic motor 310 can be discharged to the oil tank T through the pipe after rotating the rotating shaft of the hydraulic motor 310.

[0060] FIG. 9 is a system diagram showing the oil flow when the boom is boomed up in the power mode in a construction machine according to an embodiment of the present invention.

[0061] Hereinafter, with further reference to FIG. 9, the energy recovery device for a construction machine according to an embodiment of the present invention and the boom-up operation in the power mode of the construction machine 100 including the same will be described in detail. The power mode is a mode that uses the oil accumulated in the accumulator 220 to assist the power required for the boom-up operation of the boom 130.

[0062] When the boom booms up in the power mode, the AL valve AL arranged on the third line L3 is opened. At this time, the AM valve AM arranged on the fourth line L4 is closed. The oil accumulated in the accumulator 220 flows into the large chamber 142 through the first line L1 via the third line L3. In the power mode, in addition to the oil flowing into the large chamber 142 through the large chamber line 144 by the main pump 122 of the engine 120, the oil also flows in from the accumulator 220 through the third line L3 and the first line L1. Therefore, when the boom booms up in the power mode, a larger amount of oil flows into the large chamber 142 compared to the case where the power mode is not used, and thus the boom-up speed of the boom 130 can be increased. On the other hand, in the case of the power mode, the LS valve LS, the LT valve LT, and the boom-down valve 164 are also closed, and the oil flowing through the third line L3 can only flow into the large chamber 142 through the first line L1.

[0063] FIG. 10 is a system diagram showing oil flow in the release mode in a construction machine according to an embodiment of the present invention. Hereinafter, with further reference to FIG. 10, the operation of the energy recovery device for a construction machine according to an embodiment of the present invention and the release mode of the construction machine 100 including the same will be described in detail. The release mode is a mode in which the oil accumulated in the accumulator 220 is discharged to the outside. In the release mode, the release valve RE is opened. In this case, the AL valve AL and the AM valve AM can be closed. The release valve RE is provided in an on-off manner and can be provided to perform only an opening or closing operation, rather than precisely adjusting the flow rate. The release mode can be used to reduce the pressure inside the accumulator 220. In the release mode, the release valve RE is opened, and the oil accumulated in the accumulator 220 can be discharged to the oil tank T through a line connecting the accumulator 220 and the oil tank T. Such a release mode can be used, for example, when the construction machine 100 is not in operation or when the construction machine 100, the accumulator assembly 200, or the hydraulic motor assembly 300 is being serviced, and through this, safety accidents can be prevented.

[0064] As described above, an embodiment of the present invention has been explained. However, those having ordinary knowledge in the relevant technical field can make various modifications and changes to the present invention by adding, changing, deleting, or adding components, etc., without departing from the idea of the present invention described in the claims. It can be said that such modifications and changes are also included within the scope of the rights of the present invention.

Explanation of Reference Numerals

[0065] 100: Construction machine 110: Body 120: Engine 121: Shaft 122: Main pump 123: Auxiliary pump 130: Boom 140: Cylinder 141: Load 142: Large chamber 143: Small chamber 144: Large chamber line 145: Small chamber line 150: Cabinet 151: Joystick 160: Main control valve 161: Spool 162: Main valve line 163: Boom up valve 164: Boom down valve 165: Boom up valve line 166: Boom down valve line 170: Electronic control unit 200: Accumulator assembly 210: Bracket 211: Mount 212: Hollow part 213: Groove part 220: Accumulator 230: Valve assembly 240: Main pipe 241: Joint block 250: Pilot pipe 300: Hydraulic motor assembly 310: Hydraulic motor 400: Terminal unit AL: AL valve AM: AM valve LA: LA valve LS: LS valve LT: LT valve RE: Release valve L1: First line L2: Second line L3: Third line L4: Fourth line L5: Fifth line L6: Sixth line L7: Seventh line L8: Eighth line S1: First sensor S2: Second sensor S3: Third sensor S4: Fourth sensor S5: Fifth sensor T: Oil tank

Claims

1. In a construction machinery energy recovery device provided in a construction machine comprising a cylinder that moves up and down by the flow of oil and a boom driven by the cylinder, a bracket detachably fastened to the construction machine; a pressure accumulator disposed on the bracket and capable of accumulating oil; a main pipe disposed on the bracket and connected to the cylinder; and a valve assembly disposed on the bracket and connected to the main pipe, wherein the valve assembly a first line connected to the large chamber of the cylinder; a second line connecting between the first line and the pressure accumulator; and an LA valve provided in the second line and allowing oil to flow only toward the pressure accumulator and capable of controlling the flow rate, the construction machinery energy recovery device.

2. The valve assembly a third line connecting between the first line and the pressure accumulator; and an AL valve provided in the third line and allowing oil to flow only toward the first line and capable of controlling the flow rate, the construction machinery energy recovery device according to claim 1.

3. The bracket has the main pipe and the valve assembly disposed on the front side facing the boom, has a hollow portion formed on the rear side, and has a mount for mounting the pressure accumulator disposed between the front side and the rear side, the construction machinery energy recovery device according to claim 1.

4. The main control valve of the construction machine is connected with a boom-up valve for raising the boom and a boom-down valve for lowering the boom, wherein the boom-up valve and the boom-down valve are controlled by an electronic control unit based on an operation signal of a joystick of the construction machine, the construction machinery energy recovery device according to claim 1.

5. further includes a hydraulic motor assembly including a hydraulic motor that forms a rotational force by a fluid, wherein the valve assembly a fourth line connecting between the pressure accumulator and the hydraulic motor; and further includes an AM valve provided in the fourth line at all times and capable of controlling the flow rate of oil, wherein the hydraulic motor is connected to a shaft of an engine of the construction machine and can provide a rotational force to the shaft, the construction machinery energy recovery device according to claim 1.

6. The valve assembly is a fifth line connected to the small chamber of the cylinder; a sixth line branched from the first line and connected to the fifth line; and an LS valve provided in the sixth line so as to enable control of the oil flow rate, the energy recovery device for construction machinery according to claim 1.

7. The valve assembly is a seventh line branched from the first line and connected to the oil tank; and an LT valve provided in the seventh line so as to enable control of the oil flow rate, the energy recovery device for construction machinery according to claim 1.

8. The valve assembly is a release valve disposed on the flow path between the accumulator and the oil tank and operating in an on-off manner, the energy recovery device for construction machinery according to claim 1.

9. A terminal capable of communicating externally is separately provided, The valve assembly is capable of being controlled through an electronic control unit based on the operation signal of the terminal, the energy recovery device for construction machinery according to claim 1.

10. The valve assembly can be controlled in an eco mode or a power mode, The eco mode is a mode of assisting the output of the engine of the construction machinery using the oil accumulated in the accumulator, The power mode is a mode of assisting the boom-up of the boom using the oil accumulated in the accumulator, the energy recovery device for construction machinery according to claim 1.

11. A body; a cylinder connected to the body and moving up and down by the flow of oil; a boom connected to the body and driven by the cylinder; a bracket detachably fastened to the body; an accumulator disposed on the bracket and capable of accumulating oil; a main pipe disposed on the bracket and connected to the cylinder; and a valve assembly disposed on the bracket and connected to the main pipe, The valve assembly is a first line connected to the large chamber of the cylinder; second and third lines connecting between the first line and the accumulator; an LA valve provided in the second line so that oil can flow only toward the accumulator and capable of controlling the flow rate; and A construction machine including an AL valve provided in the third line so that oil flows only toward the first line and capable of flow rate control.

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