KR20230165714A - Boom energy recovery hydraulic system for construction machinery - Google Patents

Abstract

The present invention relates to a boom energy recovery hydraulic system for construction machinery, and to a boom energy recovery hydraulic system for construction machinery to recover boom energy discarded when the boom is down.
According to the present invention, the structure of the hydraulic system can be simplified, the number of valves can be minimized, but boom energy recovery can be maximized, and there are advantages in that it can be easily installed or removed from existing construction machinery.

Description

Boom energy recovery hydraulic system for construction machinery {BOOM ENERGY RECOVERY HYDRAULIC SYSTEM FOR CONSTRUCTION MACHINERY}

The present invention relates to a boom energy recovery hydraulic system for construction machinery, and more specifically, to a boom energy recovery hydraulic system for construction machinery that can recover boom energy of construction machinery.

Excavators and excavators are construction machines generally used for digging or cutting the ground, and are widely used at construction sites and various industrial sites. This excavator includes a boom whose end can be moved along a curved trajectory, and various tools including a bucket can be mounted on the end of the boom.

A hydraulic cylinder is connected to the boom, and the hydraulic cylinder drives the boom while lifting and lowering. Hydraulic cylinders are raised and lowered through oil flow in the hydraulic system. An excavator includes power means such as an engine. The engine provides the fluidity of oil flow in the hydraulic system and can simultaneously provide power for the movement of the excavator.

In general, because the weight of an excavator is very large, fuel consumption due to movement is very large. Additionally, because the boom's own weight is also heavy, a lot of fuel is consumed to drive the boom.

As eco-friendly issues have recently emerged, various technological developments and research are being conducted to improve fuel efficiency in the field of construction equipment such as excavators. For example, when the boom of an excavator goes down, a technology has been proposed to recover the potential energy of the boom and temporarily store it to assist in moving the excavator or driving the boom.

However, this conventional technology had the problem of lowering work efficiency by imposing significant restrictions on the work operation of the boom or work speed, and also had the problem of being very difficult to install on various existing excavator cranes.

Meanwhile, various methods have been proposed to recover boom energy from conventional construction machinery, one of which is to recover boom energy through controlling a plurality of valves installed on construction machinery.

However, there is a problem that a large number of valves are required to recover boom energy, which makes the entire system complicated, and increases the overall device cost due to valve installation and manufacturing costs.

Republic of Korea Patent No. 10-2309862

Based on the technical background described above, the present invention simplifies the structure of the hydraulic system for recovering boom energy discarded when the boom is down in construction equipment, minimizes the number of valves, and maximizes boom energy recovery. The purpose is to provide a boom energy recovery hydraulic system for construction machinery that can be easily installed or removed from existing construction machinery.

A boom energy recovery hydraulic system for construction equipment according to an embodiment of the present invention includes a cylinder in which a rod is raised and lowered by the flow of oil, a cylinder including a large chamber and a small chamber formed on the upper part of the large chamber, and oil in the cylinder. In the boom energy recovery hydraulic system for construction equipment, which includes an engine that provides flow, and an accumulator connected to the cylinder and the engine to accumulate oil, and controls the flow of oil to recover energy when the boom is down, the cylinder A main control valve that is connected and selectively controls the flow of oil provided to the cylinder; A hydraulic motor assembly connected to the engine and providing rotational force generated by fluid to the engine; Main pipe connected to the cylinder; and a valve assembly connected to the main pipe and including a plurality of lines through which oil flows, and a valve installed in one line selected from the plurality of lines; It is characterized by including.

As a specific embodiment, the valve assembly includes a first line connected on one side to the large chamber of the cylinder, a second line connecting the first line and the accumulator, and a fifth line connected on one side to the small chamber of the cylinder. , a sixth line branched from the first line and connected to the fifth line, and a seventh line branched from the first line and connected to the oil tank.

In one embodiment, the second line may include an AC valve that controls the flow rate of oil.

As a specific embodiment, the AC valve is opened when the boom moves down, and controls the flow rate of oil so that the oil discharged from the cylinder flows only toward the accumulator through the first line and the second line to the accumulator. Oil can be charged.

As another embodiment, the sixth line may include an AB valve that controls the flow rate of oil.

As a specific embodiment, the AB valve opens when the boom moves down, allowing the oil discharged from the large chamber of the cylinder to flow into the accumulator through the first line, and at the same time, a portion of the oil flows into the sixth line and the second line. Oil can be regenerated by controlling the flow rate of the oil so that it flows into the small chamber through the 5 line.

As another embodiment, the seventh line may include an AR valve that controls the flow rate of oil.

As a specific embodiment, the AR valve opens when the accumulator is filled with oil flowing in through the first line and the second line during the boom down operation, and controls the flow rate of oil toward the accumulator to release a portion of the oil. can be returned to the oil tank.

As one embodiment, the hydraulic motor assembly includes a variable hydraulic motor that generates rotational force when oil flows into the inside, and the inflow amount of oil can be adjusted by controlling the torque of the variable hydraulic motor.

As described above, according to the present invention, the boom energy recovery hydraulic system for construction equipment simplifies the structure of the hydraulic system for recovering boom energy discarded when the boom is down, minimizes the number of valves, and maximizes boom energy recovery. It can be easily installed or removed from existing construction machinery.

1 is a conceptual diagram showing the overall appearance of a construction machine according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing a boom energy recovery hydraulic system for construction machinery according to an embodiment of the present invention.
Figure 3 is a perspective view showing a hydraulic motor assembly according to an embodiment of the present invention.
Figure 4 is a plan view showing a pressure accumulation assembly according to an embodiment of the present invention.
Figure 5 is a perspective view showing a pressure accumulation assembly according to an embodiment of the present invention.
Figure 6 is a plan view showing a cutaway bracket of an accumulating pressure assembly according to an embodiment of the present invention.
Figure 7 is a schematic diagram showing charging of a boom energy recovery hydraulic system for construction equipment during a boom-down operation of the boom according to an embodiment of the present invention.
Figure 8 is a schematic diagram showing the regeneration of the boom energy recovery hydraulic system for construction equipment during the boom-down operation of the boom according to an embodiment of the present invention.
Figure 9 is a schematic diagram showing the return of the boom energy recovery hydraulic system for construction equipment during the boom-down operation of the boom according to an embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be exemplified and explained in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present invention, terms such as 'include' or 'have' are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. At this time, note that in the attached drawings, identical components are indicated by identical symbols whenever possible.

Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings.

Hereinafter, with reference to the attached drawings, a boom energy recovery device for construction machinery according to the present invention and a construction machine including the same will be described in detail.

1 is a conceptual diagram showing the overall appearance of a construction machine according to an embodiment of the present invention. Figure 2 is a schematic diagram showing a boom energy recovery hydraulic system for construction machinery according to an embodiment of the present invention. Figure 3 is a perspective view showing a hydraulic motor assembly according to an embodiment of the present invention. Figure 4 is a plan view showing a pressure accumulation assembly according to an embodiment of the present invention. Figure 5 is a perspective view showing a pressure accumulation assembly according to an embodiment of the present invention. Figure 6 is a plan view showing a cutaway bracket of an accumulating pressure assembly according to an embodiment of the present invention. Figure 7 is a schematic diagram showing charging of a boom energy recovery hydraulic system for construction equipment during a boom-down operation of the boom according to an embodiment of the present invention. Figure 8 is a schematic diagram showing the regeneration of the boom energy recovery hydraulic system for construction equipment during the boom-down operation of the boom according to an embodiment of the present invention. Figure 9 is a schematic diagram showing the return of the boom energy recovery hydraulic system for construction equipment during the boom-down operation of the boom according to an embodiment of the present invention.

1 to 6, the boom energy recovery hydraulic system for construction machinery according to an embodiment of the present invention is a structure that can be installed and released on construction machinery 100, and includes a main control valve 160 and It may be composed of a hydraulic motor assembly 300, a main pipe 240, and a valve assembly 230, and may include the main body 110, cylinder 140, engine 120, and accumulator assembly of the construction machine 100 ( It can be installed by connecting to the accumulator 220 and the boom 130 of 200.

Specifically, a boom 130 and a cylinder 140 may be connected to the main body 110. The cylinder 140 can move up and down by the flow of oil, and the boom 130 can rotate by the up and down operation of the cylinder 140.

An engine 120 may be disposed inside the main body 110. The engine 120 may provide a flow of oil to the cylinder 140. The engine 120 may provide driving force to a driving unit (not shown) disposed on the lower side of the main body 110.

The operation of the cylinder 140 will be examined in more detail as follows. The construction machine 100 may have a cabinet 150 in the main body 110 on which a worker can ride. A joystick 151 that can control the boom-up or boom-down operation of the boom 130 may be placed in the cabinet 150.

Specifically, the cylinder 140 moves up and down by the flow of oil and may include a rod 141 connected to the boom 130. The cylinder 140 may include a large chamber 142 and a small chamber 143 formed on the large chamber 142.

The rod 141 is disposed between the small chamber 143 and the large chamber 142 of the cylinder 140, and rises when oil flows into the large chamber 142, and falls when oil flows into the small chamber 143. can do. When the rod 141 rises, the boom 130 can boom up, and when the rod 141 falls, the boom 130 can boom down.

The main control valve 160 is connected to the cylinder 140 and can selectively control the flow of oil provided to the cylinder 140. The main control valve 160 may be placed on the construction machine 100.

The main control valve 160 may be connected to the large chamber 142 through a large chamber line 144, and the main control valve 160 may be connected to the small chamber 143 through a small chamber line 145.

Additionally, a spool 161 may be disposed on the main control valve 160.

The flow of oil may be directed toward the small chamber 143 or toward the large chamber 142 by the spool 161. That is, the rod 141 of the cylinder 140 may rise or fall by the operation of the spool 161 disposed on the main control valve 160.

The engine 120 is provided with a shaft 121, and a main pump 122 may 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 to the spool 161 and the main control valve 160 through the main valve line 162.

The spool 161 can be controlled by the boom up valve 163 and the boom down valve 164. An auxiliary pump 123 may 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 may be disposed 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 may be disposed on the boom down valve line 166. When the boom-up valve 163 opens, the spool 161 moves, allowing oil to flow into the large chamber 142, and when the boom-down valve 164 opens, the spool 161 moves, allowing oil to flow into the small chamber 143. ) can flow.

The hydraulic motor assembly 300 is connected to the engine 120 that provides the flow of oil, and can provide rotational force generated by the fluid to the engine.

The hydraulic motor assembly 300 may include a variable hydraulic motor 310. The variable hydraulic motor 310 is a device that generates rotational force by fluid, and can variably generate rotational force when oil flows into it.

The rotation axis of the variable hydraulic motor 310 may be connected to the shaft 121 of the engine 120. Accordingly, the variable hydraulic motor 310 can variably provide rotational force to the shaft 121. The hydraulic motor assembly 300 may be provided with a pipe through which oil can flow into or be discharged from the variable hydraulic motor 310, and may be provided with a pipe connected to the first oil tank T1, which will be described later.

The variable hydraulic motor 310 of the hydraulic motor assembly 300 may be installed in the engine room where the engine 120 is placed in the construction machine 100. For this purpose, the variable hydraulic motor 310 may be provided with a fastening part (not shown) that can be fastened to the engine room. In addition, pipes through which oil can be introduced or discharged and pipes connected to the first oil tank (T1) may be provided to be connected to corresponding pipes in existing construction machinery.

The torque of the variable hydraulic motor 310 is controlled through the control unit 170, which will be described later, and the inflow amount of oil can be adjusted by controlling the torque of the variable hydraulic motor 310.

The pressure accumulation assembly 200 is connected to the cylinder 140 and discharges the accumulated pressure to the cylinder 140, and the oil of the cylinder 140 can flow in and accumulate pressure. Specifically, the pressure accumulator assembly 200 includes a bracket 210, an accumulator 220, a valve assembly 230, and a main pipe 240.

The bracket 210 is detachably fastened to the main body 110 of the construction machine 100, and the accumulator 220, valve assembly 230, and main pipe 240 are disposed on the bracket 210. The bracket 210 is a part installed on the construction machine 100, and consists of the accumulator 220, the valve assembly 230, and the main pipe 240.

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

The bracket 210 has a main pipe 240 and a valve assembly 230 disposed on the front side facing the boom 130, a hollow portion 212 is formed on the rear side, and an axis is formed between the front side and the rear side. A press 220 may be disposed. A groove 213 may be formed on the front side of the bracket 210.

The groove portion 213 may be formed by being depressed from the front end of the bracket 210 to the rear side. The shape of the groove 213 is shaped to correspond to the shape of the outer surface of the cabinet 150 of the construction machine 100, thereby minimizing spatial interference between the cabinet 150 and the bracket 210. The main pipe 240 and the valve assembly 230 may be disposed on the front side of the bracket 210 in a portion where the groove portion 213 is not formed. That is, a groove 213 may be formed on one side of the front side of the bracket 210, and the main pipe 240 and the valve assembly 230 may be disposed on the other side.

Due to this structure of the bracket 210, the portion of the bracket 210 where the main pipe 240 and the valve assembly 230 are placed can be placed closer to the boom 130, and thus the cylinder 140 The length of various pipes or lines connected to can be minimized, so the flow resistance of the oil flow can be minimized.

A hollow portion 212 may be formed on the rear side of the bracket 210. An engine 120 may be disposed on the rear side of the pressure accumulation assembly 200. By using the hollow portion 212, the influence of heat generated from the engine 120 on the accumulator 220 can be reduced. Additionally, the hollow portion 212 may reduce the weight of the bracket 210. The hollow portion 212 may be formed not only on the rear side of the bracket 210, but also on the central or front side of the bracket 210.

Additionally, the accumulator 220 may be arranged to be spaced apart from the rear end (rear end) of the bracket 210. Through this, even when the accumulator assembly 200 is installed on the construction machine 100, it is convenient to open the engine room for maintenance of the engine 120, and it can be easy for workers to separate and install the accumulator 220. . In addition, it is possible to prevent heat and vibration generated from the engine 120 from being directly transmitted to the accumulator 220.

A mount 211 may be disposed between the front and rear sides of the bracket 210. The mount 211 is configured to mount the accumulator 220. The accumulator 220 can be arranged at a predetermined distance from the upper surface of the bracket 210 by the mount 211. Accordingly, the accumulator 220 can be easily separated and installed, and heat and vibration generated in the engine 120 can be prevented from being directly transmitted to the accumulator 220.

The bracket 210 may be detachably installed on the construction machine 100. The bracket 210 can be installed by modifying the exterior or interior of the existing construction machine 100. The specific size or detailed shape of the bracket 210 may be partially modified depending on the construction machine 100 to be installed. Due to this configuration of the bracket 210, the energy recovery device according to the present invention can be easily and conveniently installed on various existing construction machines 100.

Oil may be accumulated in the accumulator 220, and when necessary, oil previously accumulated in the accumulator 220 may be discharged from the accumulator 220. The main pipe 240 is connected to the cylinder 140. The valve assembly 230 is connected to the main pipe 240.

The opening and closing of the valve assembly 230 can be controlled by the pilot pipe 250, respectively. Specifically, the valve assembly 230 includes a first line (L1), a second line (L2), a fifth line (L5), a sixth line (L6), and a seventh line (L7), and the AC valve (AC), AB valve (AB), and AR valve (AR).

The first line L1 is a line connected to the large chamber 142 of the cylinder 140. The first line L1 may be connected to the large chamber line 144. The second line (L2) is a line connecting the first line (L1) and the accumulator 220. An AC valve (AC) may be disposed in the second line (L2). The AC valve (AC) is a valve provided to control the oil flow. It controls the flow of oil only from the second line (L2) toward the accumulator 220 and charges oil to the accumulator 220. It could be a valve.

The AC valve (AC) is opened when the boom 130 moves down, allowing the oil discharged from the cylinder 140 to flow toward the accumulator 220 through the first line (L1) and the second line (L2). Oil can be charged to the accumulator 220 by controlling the oil flow rate so that only the oil flows in, and the accumulator 220 can accumulate the inflow oil.

The fifth line L5 is a line connected to the small chamber 143 of the cylinder 140. The fifth line L5 may be connected to the small chamber line 145. The sixth line (L6) is a line that branches off from the first line (L1) and is connected to the fifth line (L5). An AB valve (AB) may be disposed in the sixth line (L6) to enable control of the flow rate of oil in the sixth line (L6). The AB valve (AB) is a regeneration valve that introduces a portion of the oil flowing in the first line (L1) into the small chamber 143 of the cylinder 140 through the sixth line (L6) and the fifth line (L5). You can.

The seventh line (L7) is a line that branches off from the first line (L1) and is connected to the third oil tank (T3), which will be described later. An AR valve (AR) provided to control the flow rate of oil in the seventh line (L7) may be disposed in the seventh line (L7). The AR valve (AR) may be a return valve that allows a portion of the oil flowing into the accumulator 220 to flow into the oil tank (T) when the accumulator 220 is full of oil.

The valve assembly 230 may include a fourth line (L4) connecting the accumulator 220 and the variable hydraulic motor 310. Since the variable hydraulic motor 310 capable of controlling the flow rate of oil is installed, a separate valve is not required in the fourth line L4, but a CM valve (CM, not shown) capable of controlling the flow rate of oil may be further included.

Accordingly, the oil accumulated in the accumulator 220 flows into the variable hydraulic motor 310 through the fourth line (L4), thereby rotating the variable hydraulic motor 310.

The valve assembly 230 may further include an eighth line (L8) connected to the fifth line (L5) and the sixth line (L6). The eighth line (L8) may be connected to the fourth oil tank (T4), which will be described later. Through the eighth line (L8), oil that has passed through the AB valve (AB) may flow into the fourth oil tank (T4).

The valve assembly 230 may include a release valve (RE). The release valve (RE) is disposed on the flow path between the accumulator 220 and the second oil tank (T2), which will be described later. The release valve (RE) operates in an on-off manner.

The valve assembly 230 may include a solenoid valve (SOL) connected in parallel to the release valve (RE). Specifically, a solenoid valve (SOL) valve is connected to each pipe before and after the release valve (RE), and the solenoid valve (SOL) may be arranged in parallel with the release valve (RE).

Accordingly, a double release valve (RE) and a solenoid valve (SOL) may be installed between the accumulator 220 and the second oil tank (T2).

As seen above, the AC valve (AC), AB valve (AB), AR valve (AR), release valve (RE), and solenoid valve (SOL) of the valve assembly 230 are all controlled by the control unit 170. You can.

The main pipe 240 is a pipe connected to the cylinder 140. One main pipe 240 may be provided, and the first line L1 and the fifth line L5 may be formed simultaneously in the main pipe 240. Alternatively, two main pipes 240 may be provided, and a first line (L1) and a fifth line (L5) may be formed separately in each. A joint block 241 may be placed at the distal end of the main pipe 240. The large chamber 142 and the small chamber 143 of the cylinder 140 may be connected to the joint block 241.

The oil tank (T) may be formed of at least one oil tank (T) to allow oil to flow in and be stored therein, or to allow the stored oil to flow out.

The oil tank (T) includes a first oil tank (T1) connected to the hydraulic motor 310 of the hydraulic motor assembly 300 by a pipe, a second oil tank (T2) connected to the release valve (RE) by a pipe, It may include a third oil tank (T3) connected to the 7th line and a fourth oil tank (T4) connected to the 8th line.

The boom energy recovery hydraulic system for construction equipment according to an embodiment of the present invention can be controlled by the mobile 400.

A mobile 400 capable of communicating with the control unit 170 is provided outside the construction machine 100, and the valve assembly 230 of the pressure accumulation assembly 200 operates on the control unit 170 based on the operation signal of the mobile 400. It can be controlled through. The mobile 400 may be provided with an input means for inputting a control command and an output means such as a display for displaying the operating status of the pressure accumulation assembly 200. For example, the mobile 400 may be a terminal owned by a user, or may be any one of a smartphone, PDA, laptop, or tablet. The mobile 400 can communicate wirelessly with the control unit 170 using communication methods such as Wi-Fi, Bluetooth, Zigbee, Beacon, and RFID, and the mobile ( The communication method of 400) is not limited to this.

The control unit 170 may control the operation of the construction machine 100 based on the manipulation signal. For this purpose, the control unit 170 may be an electronic control unit (ECU).

Specifically, the control unit 170 operates the boom energy recovery hydraulic system for construction equipment by controlling the operation of the hydraulic motor assembly 300 and the accumulating pressure assembly 200 based on the operation signal according to the control operation of the mobile 400. You can do it.

The control unit 170 can control whether to open or close the boom-up valve 163 or the boom-down valve 164 based on a manipulation signal according to the control operation of the mobile 400.

In addition, the control unit 170 can control the operation of the construction equipment 100 and whether the boom-up valve 163 or the boom-down valve 164 is opened or closed based on the operation signal of the joystick 151.

For this purpose, the joystick 151 may be equipped with a first sensor (S1) and a second sensor (S2). The first sensor (S1) detects the pressure change during the boom-up operation of the joystick 151 and generates a manipulation signal, and the second sensor (S2) detects the pressure change during the boom-down operation of the joystick 151 and operates it. A signal can be generated.

The operation signal generated by the first sensor (S1) and the second sensor (S2) is transmitted to the control unit 170, and the control unit 170 operates the boom-up valve 163 or the boom-down valve ( 164) can be controlled to open or close.

Here, the manipulation signal generated by the first sensor S1 and the second sensor S2 may be transmitted to the mobile 400 through the control unit 170. Through this, it is possible to control whether the boom-up valve 163 or the boom-down valve 164 is opened or closed using the mobile 400.

Meanwhile, the boom down valve 164 may also be placed in 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, during the boom-down operation of the joystick 151, the control unit 170 controls the boom-down valve 164 to close, allowing oil to flow from the large chamber 142 to the main control valve 160. It may also block the flow.

Due to the structure described above, a specific mode can be selected through the control unit 170, and the control unit 170 controls the operation of the hydraulic motor assembly 300 and the accumulator assembly 200 to operate the construction machine 100. It can be operated in various modes.

Here, setting, changing, and canceling various modes can be accomplished by controlling the control unit 170 through the mobile device 400. Additionally, it can be controlled by the control unit 170 through a manipulation signal from the joystick 151.

By manipulating the control unit 170, boom energy can be recovered when the boom of the construction machine 100 is operated down.

Specifically, when the boom 130 moves down, oil can be charged to the accumulator 220 to accumulate pressure, and when the boom 130 moves down, some of the oil flowing into the accumulator 220 is regenerated. It can be used during the boom-up operation, and when the accumulator 220 is full of oil during the boom-down operation of the boom 130, part of the oil flowing into the accumulator 220 can be returned to the oil tank (T).

The charging process of the boom energy recovery hydraulic system for construction equipment during the boom down operation of the boom according to an embodiment of the present invention will be described with reference to FIG. 7.

Potential energy resulting from the boom-down operation of the boom 130 is recovered and charged to the accumulator 220, and then the stored energy can be reused. Specifically, when the boom is down, the potential energy stored in the accumulator 220 can be reused to save fuel and improve performance.

When the boom 130 goes down, the boom down valve 164 is closed, oil flows into the small chamber 143 of the cylinder 140 to lower the rod 141 of the cylinder 140, and the rod (141) is lowered. As the oil 141) is lowered, the oil inside the large chamber 142 is discharged through the first line (L1).

Oil flowing in the first line (L1) flows into the accumulator 220 through the second line (L2), and the oil flowing into the accumulator 220 can be reused and recycled after accumulating pressure.

At this time, since the boom down valve 164 is locked, the oil does not flow toward the main control valve 160 and can be discharged only to the first line (L1).

Through this process, the potential energy of the boom 130 can be stored in the accumulator 220, and the stored potential energy can be used to save fuel or improve the performance of the construction machine 100. It can be improved.

The regeneration process of the boom energy recovery hydraulic system for construction equipment during the boom down operation of the boom according to an embodiment of the present invention will be described with reference to FIG. 8.

When the boom 130 moves down, oil flows into the accumulator 220 to store the potential energy of the boom 130 in the accumulator 220, and oil flows into the small chamber 143. You can increase the boom-down speed by doing this.

Specifically, when the boom 130 booms down, the AB valve (AB) is opened to allow part of the oil flowing in the first line (L1) to flow through the sixth line (L6) and the fifth line (L5). In addition to flowing into the small chamber 143 of the cylinder 140, the remainder of the oil flowing in the first line (L1) can be flowed into the accumulator 220 through the second line (L2).

In this way, the boom down speed of the boom 130 can be increased by rapidly lowering the rod 141 by re-introducing the oil into the small chamber 143 and the process of accumulating oil in the accumulator 220.

Meanwhile, an eighth line L8 may be further connected to the fifth line L5 and the sixth line L6. The eighth line (L8) may be connected to the oil tank (T), that is, the fourth oil tank (T4). Through the eighth line (L8), oil that has passed through the AB valve (AB) may flow into the fourth oil tank (T4).

The return process of the boom energy recovery hydraulic system for construction equipment during the boom down operation of the boom according to an embodiment of the present invention will be described with reference to FIG. 9.

When the accumulator 220 is full of oil during the boom down operation of the boom 130, the oil flowing into the accumulator 220 is diverted to the third oil tank (T3) to facilitate the boom down of the boom 130. You can do it.

Specifically, when the accumulator 220 is full of oil during the boom-down operation, the AR valve (AR) is opened, and a part of the oil flowing in the first line (L1) is discharged through the seventh line (L7). 3 It can be introduced into the oil tank (T3).

In this way, when the accumulator 220 is full of oil, the boom down of the boom 130 may no longer operate. In this case, the oil is diverted to the third oil tank (T) to lower the boom 130. Boomdown can be done smoothly

Here, the fifth sensor S5 may be disposed in the second line L2 and in front of the accumulator 220, and the fifth sensor S5 may measure the pressure in front of the accumulator 220. Therefore, it is possible to measure whether the accumulator 220 is full of oil using the fifth sensor S5.

Meanwhile, in order to reduce the internal pressure of the accumulator 220, the pressure may be relieved by discharging the oil accumulated in the accumulator to the outside.

Specifically, in order to reduce the internal pressure of the accumulator 220, the release valve (RE) is opened. Here, the release valve (RE) is preferably provided in an on/off manner to enable only a simple opening or closing operation rather than precisely controlling the flow rate of oil, but is not limited to this.

In this way, the release valve (RE) is opened to discharge a portion of the oil accumulated in the accumulator 220 to the second oil tank (T2) through the pipe connecting the accumulator 220 and the second oil tank (T2). The internal pressure of the accumulator 220 can be reduced.

For example, when the pressure of the oil flowing into the accumulator 220 and accumulating exceeds the preset pressure range, the release valve (RE) is always opened to remove a portion of the oil flowing into the accumulator 220. 2 The internal pressure of the accumulator 220 can be reduced by flowing into the oil tank (T2).

Meanwhile, when performing maintenance on the construction machine 100, the solenoid valve (SOL) is opened to allow all of the oil in the accumulator 220 to flow into the second oil tank (T2) to set the pressure relief mode and then proceed with maintenance. You can.

For example, when the construction machine 100 is not in operation or when the construction machine 100, hydraulic motor assembly 300, or accumulator assembly 200 is being maintained, the solenoid valve (SOL) is opened to open the accumulator ( Safety accidents, etc. can be prevented by flowing all of the oil in 220) into the second oil tank (T2) to relieve the internal pressure of the accumulator 220 and then proceed with maintenance.

In this way, even during maintenance of the construction machine 100, only the release valve (RE) is opened to relieve the pressure of the accumulator 220, or only the solenoid valve (SOL) is opened to relieve the pressure of the accumulator 220. , the pressure in the accumulator can be relieved by opening both the release valve (RE) and the solenoid valve (SOL).

Here, when the release valve (RE) is opened, the solenoid valve (SOL) may be closed, and similarly, when the solenoid valve (SOL) is opened, the release valve (RE) may be closed.

Meanwhile, the recovery operation of potential energy generated when the boom 130 is brought down can be temporarily suspended. That is, when explaining with reference to FIGS. 2 and 7, during the boom-down operation of the boom 130, if the boom 130 touches the ground and a greater force is required to boom-down the boom 130, Oil accumulation in the accumulator 220 can be stopped.

At this time, the third sensor (S3) and the fourth sensor (S4) may be placed on the first line (L1) and the fifth line (L5), and the third sensor (S3) and fourth sensor (S4) are always Oil pressure can be measured, and the measured oil pressure value can be transmitted to the control unit 170.

The control unit 170 can determine whether the boom 130 has reached the ground through these measurement values.

Specifically, when the control unit 170 determines that the boom 130 has touched the ground, it closes the AC valve (AC) of the second line (L2) connected to the accumulator 220, thereby Oil pressure accumulation can be temporarily stopped.

In addition, when the control unit 170 determines that the boom 130 has reached the ground, it closes both the AC valve (AC) and the AR valve (AR) and opens the AB valve (AB) to discharge the discharge from the large chamber 142. By allowing the oil to flow only into the small chamber 143, the accumulation of oil pressure in the accumulator 220 can be temporarily stopped.

That is, the AC valve (AC) disposed in the second line (L2) and the AR valve (AR) disposed in the seventh line (L7) are closed, and the AB valve (AB) disposed in the sixth line (L6) is closed. By opening, it can be controlled so that all the oil discharged from the large chamber 142 flows into the small chamber 143.

Above, an embodiment of the present invention has been described, but those skilled in the art can add, change, delete or add components without departing from the spirit of the present invention as set forth in the patent claims. The present invention may be modified and changed in various ways, and such modifications and changes will also be included within the scope of the rights of the present invention.

100: Construction machinery
110: main 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: control unit
200: Accumulated pressure assembly
210: bracket
211: mount
212: Ministry of SMEs and Startups
213: Home Department
220: accumulator
230: Valve assembly
240: main piping
241: Joint block
250: Pilot piping
300: Hydraulic motor assembly
310: Hydraulic motor
400: mobile
AC: AC valve
AB: AB valve
AR: AR valve
RE: Release valve
SOL: Solenoid valve
L1: first line
L2: 2nd line
L4: 4th line
L5: 5th line
L6: 6th line
L7: 7th line
L8: 8th line
S1: first sensor
S2: second sensor
S3: Third sensor
S4: 4th sensor
S5: Fifth sensor
T1: 1st oil tank
T2: Second oil tank
T3: Third oil tank
T4: 4th oil tank

Claims (9)

A rod moves up and down by the flow of oil, a cylinder including a large chamber and a small chamber formed at the top of the large chamber, an engine that provides a flow of oil to the cylinder, and an engine connected to the cylinder and the engine to provide oil In the boom energy recovery hydraulic system for construction machinery, which includes an accumulator that accumulates pressure and recovers energy when the boom is down by controlling the flow of oil,
a main control valve connected to the cylinder and selectively controlling the flow of oil provided to the cylinder;
a hydraulic motor assembly connected to the engine and providing rotational force generated by fluid to the engine;
a main pipe connected to the cylinder; and
a valve assembly connected to the main pipe and including a plurality of lines through which oil flows, and a valve installed in one line selected from the plurality of lines;
A boom energy recovery hydraulic system for construction machinery, comprising:
In claim 1,
The valve assembly is,
A first line connected on one side to the large chamber of the cylinder, a second line connecting the first line and an accumulator, a fifth line connected on one side to the small chamber of the cylinder, and in the first line A boom energy recovery hydraulic system for construction equipment, comprising a sixth line branched and connected to the fifth line, and a seventh line branched from the first line and connected to an oil tank.
In claim 2,
The second line is,
A boom energy recovery hydraulic system for construction machinery, comprising an AC valve that controls the flow rate of oil.
In claim 3,
The AC valve is,
The boom is opened when the boom is operated down, and the flow rate of the oil is controlled so that the oil discharged from the cylinder flows only toward the accumulator through the first line and the second line, characterized in that the oil is charged to the accumulator. Boom energy recovery hydraulic system for construction machinery.
In claim 2,
The sixth line is,
A boom energy recovery hydraulic system for construction machinery, comprising an AB valve that controls the flow rate of oil.
In claim 5,
The AB valve is,
When the boom moves down, it opens, allowing oil discharged from the large chamber of the cylinder to flow into the accumulator through the first line, and at the same time, part of the oil flows into the small chamber through the sixth line and fifth line. A boom energy recovery hydraulic system for construction machinery, characterized in that it regenerates oil by controlling the oil flow rate as much as possible.
In claim 2,
The seventh line is,
A boom energy recovery hydraulic system for construction machinery, comprising an AR valve that controls the flow rate of oil.
In claim 7,
The AR valve is,
During the boom down operation of the boom, when the oil flowing in through the first line and the second line fills the accumulator, it opens, controls the flow rate of oil toward the accumulator, and returns part of the oil to the oil tank. Boom energy recovery hydraulic system for construction equipment.
In claim 1,
The hydraulic motor assembly is,
It includes a variable hydraulic motor that generates rotational force when oil flows inside,
A boom energy recovery hydraulic system for construction equipment, characterized in that the inflow amount of oil is adjusted by controlling the torque of the variable hydraulic motor.

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