KR20170101492A

KR20170101492A - Floating System of Boom in Construction Equipment

Info

Publication number: KR20170101492A
Application number: KR1020160024071A
Authority: KR
Inventors: 송민규
Original assignee: 현대중공업 주식회사
Priority date: 2016-02-29
Filing date: 2016-02-29
Publication date: 2017-09-06

Abstract

The present invention relates to a boom floating system of a construction machine, and more specifically, to a boom floating system including a main pump, which is connected to an engine and drives a boom cylinder comprising a head chamber and a load chamber, and a main control valve for controlling the driving of the boom cylinder. The present invention includes: a head valve for controlling pressure oil in the head chamber; a rod valve for controlling the pressure oil in the load chamber; and floating control device for, in a boom floating mode, supplying a separate pressure fluid into the head chamber so as to maintain the head chamber at a predetermined constant pressure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a boom-

The present invention relates to a boom floating system of a construction machine.

Construction machinery generally refers to construction and civil engineering machinery, and each structure such as roads, rivers, harbors, railways, and plants has a structure and performance suited to its characteristics. In other words, the construction equipment can be divided into excavation equipment, loading equipment, conveying equipment, loading equipment, compaction equipment, foundation equipment and the like due to the variety of work done in the industrial field. Specifically, the construction equipment can be classified into bulldozer, excavator, , Rollers, and the like.

The most basic work performed in the industrial field is digging. In the case of industrial construction, excavation works are mostly carried out by excavating the ground to a certain depth and installing various structures or laying pipes on the ground.

An excavator is a construction machine that performs excavation work for digging the ground in civil engineering, construction, construction site, loading work for carrying earthworks, crushing work for dismantling the building, stop work for arranging the ground (or flattening work) And an upper revolving body and a working device which are mounted on the traveling body and rotate 360 degrees.

The excavator is divided into an infinite track crawler excavator and a tire type wheel excavator according to the driving method of the traveling body. Crawler excavator is more widely used in each work site from 1 ton to more than 100 tons of equipment because it is stable and work productivity compared to wheel excavator. Wheel excavator is compared with crawler excavator It is used mainly in the work site where the work stability can be reduced but the road can be traveled and the work place can be moved without a trailer and frequently work and movement are required.

In addition, excavators can be used with appropriate working equipment depending on the state of the earth and rock, the type of work and the application. Buckets for general excavation and excavation, breakers for crushing hard ground, rocks, and crushers used for dismantling and crushing buildings.

The working mode of the excavator can be largely divided into a floating mode for planarization, a breaker mode for crushing or chopping, and a normal mode for other operations such as excavation, loading and turning.

In an operation using an excavator, a flattening operation of picking up the ground surface is often carried out while moving the bucket in the forward and backward directions. But at work, the operator has to control the boom, arm, and bucket every minute, so the fatigue he feels is high. To compensate for this, use the boom float function. The boom float function connects the load chamber and the head chamber of the boom cylinder to the tank to make them unloaded, and the boom moves freely according to the shape of the ground only by the operation of the arm. Therefore, it is possible to work with only the arm operation without a separate boom operation when the ground is grounded along the curved ground surface, thereby improving the operator's convenience.

However, when the force applied to the bucket by the bucket during the planarizing operation is too large, the bucket is likely to be pounded in the ground when the ground is relatively soft compared to the general ground, There are technical limitations.

Korean Patent Publication No. 10-2010-0056087 (published on May 27, 2010)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a boom floating system for a construction machine that facilitates ground planarization regardless of the condition of the ground.

It is also an object of the present invention to provide a boom floating system for a construction machine capable of maintaining a load applied to the ground by a bucket constantly and holding the same, thereby achieving a more complete planarization operation.

A boom floating system of a construction machine according to an aspect of the present invention includes a main pump connected to an engine for driving a boom cylinder constituted by a head chamber and a load chamber and a main control valve for controlling the operation of the boom cylinder A boom floating system of a machine, comprising: a head valve for controlling pressure oil in the head chamber; A rod valve for controlling pressure oil in the load chamber; And a floating control device for supplying a separate pressurized oil to the head chamber in a boom floating mode so that the head chamber is maintained at a predetermined constant pressure.

Specifically, the floating control device includes: a gear pump that discharges the pressure oil so that the head chamber maintains the predetermined constant pressure; And a relief valve installed on the pressure oil line connected to the tank between the gear pump and the head valve.

Specifically, the floating control device includes: a gear pump that discharges the pressure oil so that the head chamber maintains the predetermined constant pressure; A check valve installed between the gear pump and the head valve; A first relief valve installed on a pressure line connecting between the check valve and the head valve by a tank; And a second relief valve installed on a pressure line connecting the check valve and the gear pump to the tank.

Specifically, the gear pump can be operated by receiving power from the engine.

Specifically, the head valve is a bidirectional flow port for flowing pressurized oil in both directions, a first port for bringing the floating function ON state in the boom floating mode; And a bi-directional shutoff port for blocking the flow of pressurized fluid, the second port allowing the floating function off state to be brought into the state.

Specifically, the rod valve is a bidirectional flow port for flowing pressurized oil in both directions, a first port for bringing the floating function ON state in the boom floating mode; And a check valve type port for allowing the pressurized oil to flow into the tank, the second port being a floating function off state.

The boom floating system of the construction machine according to the present invention can reduce the weight of the boom that can be received from the ground by relatively constructing the floating control device so as to apply predetermined pressure to the head chamber of the boom cylinder, It is possible to prevent the bucket from being pushed into the ground due to the weight of the boom even in the smooth ground condition, so that it is possible to smooth the ground planing operation irrespective of the condition of the ground and to secure the freedom to implement the boom floating function can do.

Further, in the boom floating system of the construction machine according to the present invention, the load applied to the ground by the bucket can be constantly maintained by using the floating control device, thereby achieving a more complete planarization operation.

1 is a side view of a construction machine operated by a boom float system of a construction machine according to an embodiment of the invention.
2 is a circuit diagram showing a boom floating system of a construction machine according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a side view of a construction machine operated by a boom floating system of a construction machine according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a boom floating system of a construction machine according to an embodiment of the present invention.

Hereinafter, with reference to FIG. 1, a construction machine 100 operated by a boom floating system 200 of a construction machine according to an embodiment of the present invention will be described first.

As shown in FIG. 1, the construction machine 100 may include a working device 110, a swivel body 120, and a traveling unit 130.

The construction machine 100 is a type of crawler that performs operations such as excavation work for digging the ground at the construction site, loading work for transporting the soil, crushing work for dismantling the building, planarizing work for arranging the ground Of excavators. Of course, the construction machine 100 may be various equipment to which the boom floating system 200 is applied, not an excavator. In the following description, the construction machine 100 is a crawler excavator. It should be understood, however, that the present invention is not limited to the embodiment but is merely an example.

The working device 110 is provided on one side of the construction machine 100 and comprises a boom 111, an arm 113 and a bucket 115. The boom 111 is connected to two boom cylinders 112 And the arm 113 is actuated by the arm cylinder 114, so that the position of the bucket 115 can be adjusted. The bucket 115 can perform detailed work by the bucket cylinder 116. [ Here, although the reference numeral of the boom cylinder is denoted by '112', when describing the boom floating system 200 according to the present invention to be described later, the boom cylinder is represented by '230' for convenience. The boom cylinder 112 of the construction machine 100 and the boom cylinder 230 of the boom float system 200 may be the same but needless to say they are not necessarily the same.

For example, when the bucket cylinder 116 is compressed, the bucket 115 is moved forward for digging. When the bucket cylinder 116 is pulled, the bucket 115 is rotated inward, , Digging operation, loading operation, and the like.

More specifically, among the operations using the construction machine 100, a planarization operation of picking up the ground surface is performed while moving the bucket 115 in the forward and backward directions. At this time, the floating function of the boom 111 is used. The floating function of the boom 111 is to make the load chamber and the head chamber of the boom cylinder 112 connected to each other by a tank so that the boom 111 is free of load so that the bucket 115 can freely move freely It is moving. Therefore, it is possible to work only by the operation of the arm 113 without manipulating the boom 111 separately during the grounding work of growing the ground along the curved ground surface, thereby improving the operator's convenience.

However, conventionally, when the force applied to the ground by the bucket 115 is too large, the bucket 115 may pierce the ground in a condition where the ground surface is relatively soft compared to the general ground, There is a technical limitation in that a smooth leveling operation can not be performed. In this embodiment, the boom floating system 200 attempts to overcome this technical limitation. A detailed description related to the boom float system 200 will be described later.

The swivel body 120 includes a swivel frame 121 and a swivel frame 121 which are connected to the front portion of the swivel body 120 and are mounted on a traveling unit 130 to be described later and can rotate 360 degrees, An engine 125, and a counterweight 127, which are disposed on the vehicle. Although the reference numeral of the engine is denoted by "125" herein, when describing the boom floating system 200 according to the present invention to be described later, it is denoted by "290" for convenience of engine. The engine 125 of the construction machine 100 and the engine 290 of the boom float system 200 may be the same but needless to say they are not necessarily the same.

The operating room 123 is provided with various operating devices such as a work device operating section (not shown), a turning operation section (not shown) and a traveling operating section (not shown) . The work device operating section may be provided with a plurality of levers or switches capable of respectively operating the detailed configuration of the working device 110. [ The swivel body operating section can operate the turning operation of the swivel body 120, and a plurality of levers or switches can be provided. The traveling control unit may include an accelerator pedal, a braking pedal, and a plurality of traveling levers for controlling the traveling direction of the traveling unit 130, which will be described later.

The engine 125 is installed in the machine room and transmits the driving force to the working unit 110 and a traveling unit 130 to be described later. The engine 125 can cause the working device 110 to move by the pump connected to the engine 125 being operated by the engine 125 to supply the pressurized oil to each cylinder 112,114,116.

Here, the pump connected to the engine 125 may be a main pump 210 and a gear pump 281 that supply pressurized oil to the boom float system 200.

The traveling unit 130 serves to move the construction machine 100. A left and right swinging wheel 133 is rotatably installed on the front side of the truck or track frame 131, And an infinite track 137 is provided to rotate the swing arm 135 and to surround the swinging wheel 133 and the drive wheel 135.

2 is a circuit diagram showing a boom floating system of a construction machine according to an embodiment of the present invention.

2, the boom floating system 200 of the construction machine 100 includes a main pump 210, a pilot pump 220, a boom cylinder 230, a main control valve 240, A valve 260 for a head, a valve 270 for a rod, and a floating controller 280.

1, and the boom cylinder 230 may be the boom cylinder 112 of the construction machine 100 shown in Fig. 1 or other construction It can be the boom cylinder of the machine.

The main pump 210 is connected to the head chamber 231 or the load chamber 232 of the boom cylinder 230 to be described later by the head side pressure applying path 201 or the rod side pressure applying path 202, The cylinder 230 can be driven. A main control valve 240 to be described later may be provided on the head side and the rod side pressure oil lines 201, 202 connecting the main pump 210 and the boom cylinder 230.

The pilot pump 220 can switch the states of various valves or various spools connected by a pilot signal line (not shown), and whether or not the pilot signal is applied can be controlled by a remote control unit 250 have.

The boom cylinder 230 can be driven by being connected to the main pump 210 by the head side pressure applying path 201 or the rod side pressure applying path 202 and the head chamber 231 and the load chamber 232, &Lt; / RTI > The cross sectional area of the head chamber 231 is about 1.5 to 2 times larger than the cross sectional area of the rod chamber 232 because there is a rod connected to the boom 111 in the rod chamber 232. Generally, two boom cylinders 230 are provided, and a safety valve 233 may be installed in the head chamber 231 of each boom cylinder 230.

The main control valve 240 is provided between the head side pressure transfer path 201 and the load side pressure transfer path 202 between the main pump 210 and the boom cylinder 230 to start the boom cylinder 230, Stop and direction switching can be controlled.

The remote control unit 250 can control the main control valve 240, various valves, or various spools by controlling whether or not the pilot signal applied from the pilot pump 220 is applied.

The head valve 260 may be provided on the head side pressure return line 204 where one end is connected to the head chamber 231 of the boom cylinder 230 and the other end is connected to the floating control device 280 And the pressure of the head chamber 231 is controlled to return to the tank 206 through a floating control device 280 to be described later or a separate pressurized oil is supplied to the head chamber 231 by the floating control device 280 Can be controlled.

The head valve 260 may be configured to be switched to the first port 261 to make the floating function ON state and the second port 262 to make the floating function OFF state. The first port 261 may be a bidirectional flow port that allows pressurized fluid to flow in both directions and the second port 262 may be a bidirectional shutoff port that blocks pressure flow.

Specifically, when the head valve 260 is switched to the first port 261, the pressure of the head chamber 231 is returned to the tank 206 through the head side pressurized oil return line 204, A state in which the head chamber 231 is maintained at a predetermined constant pressure by supplying a separate pressurized oil to the head chamber 231 in a state in which the boom 111 is lowered, So that the floating function can be turned on so that the directional floating function can be performed.

When the head valve 260 is switched to the second port 262, the pressurized oil in the head chamber 231 is blocked from returning to the tank 206 through the head side pressurized oil return line 204, Off state.

The rod valve 270 may be provided on the rod side pressure return line 205 having one end connected to the load chamber 232 of the boom cylinder 230 and the other end connected to the tank 206, It is possible to control the pressure oil in the load chamber 232 to return to the tank 206.

The rod valve 270 may be configured to be switched to the first port 271 to be in the floating function ON state and the second port 272 to be in the floating function OFF state. The first port 271 may be a bidirectional flow port that allows pressurized fluid to flow in both directions and the second port 272 may be a check valve port that allows pressurized oil to flow to the tank 206.

Specifically, when the rod valve 270 is switched to the first port 271, the pressure oil in the rod chamber 232 returns to the tank 206 via the rod-side pressure oil return line 205, The floating function is turned on so as to allow the boom 111 to perform an upward floating function. When the second port 272 is switched to the second port 272, the pressure of the load chamber 232 is reduced to the load- The return to the tank 206 through the line 205 is blocked and the floating function is turned off.

The float control device 280 may be connected to the other end of the head side pressure return line 204 provided with the head valve 260 and operated in the boom floating mode so that pressurized oil in the head chamber 231 flows into the tank 206, Or the head chamber 231 is supplied with a separate pressurized fluid so that the head chamber 231 is always maintained at a predetermined constant pressure. The floating control device 280 may include a first relief valve 281, a check valve 282, a gear pump 283, and a second relief valve 284.

The first relief valve 281 can be installed on the first pressure fluid line 285a. The first pressure line 285a may be configured such that one end is connected to the other end of the head side pressurized oil return line 204 and the other end is connected to the tank 206. [

This first relief valve 281 is set to a pressure such that the head chamber 231 of the boom cylinder 230 is maintained at a predetermined constant pressure.

That is, when the internal pressure of the head chamber 231 is lower than a preset constant pressure in the boom float mode, the first relief valve 281 is operated so that a separate pressure oil discharged from the gear pump 283, which will be described later, At this time, a separate pressurized fluid is not directly returned to the tank 206 through the first pressure fluid line 285a, so that a predetermined pressure is maintained in the first pressure fluid line 285a, 231) is maintained at a predetermined constant pressure.

It goes without saying that the first relief valve 281 returns the pressure oil in the head chamber 231 to the tank 206 when the internal pressure of the head chamber 231 is higher than a preset constant pressure in the boom floating mode.

The first relief valve 281 is configured such that the pressure inside the head chamber 231 of the boom cylinder 230 is instantaneously increased by a predetermined impact or the like during the flattening operation in the boom floating mode, The pressure oil can be returned to the tank 206 to serve as a stabilizing device for relieving the impact.

The check valve 282 can be installed on the second pressure fluid line 285b. The second pressure line 285b has one end connected to the other end of the head side pressure return line 204 and one end of the first pressure line 285a and the other end connected to the third pressure line 285c, May be configured to be connected to the fourth pressure well 285d.

The check valve 282 may be configured to prevent the pressure oil from flowing backward from the head chamber 231 side of the boom cylinder 230 to the gear pump 283 side to be described later in the boom float mode, 283). &Lt; / RTI >

The gear pump 283 can be operated by receiving power from the engine 290 and can supply a separate pressurized oil to the head chamber 231 of the boom cylinder 230 through the third pressure fluid line 285c . The third pressure roller 285c may be configured such that one end thereof is connected to the other end of the second pressure roller 285b and the fourth pressure roller 285d to be described later and the other end thereof is connected to the gear pump 283 .

The gear pump 283 discharges the separate pressurized oil so that the head chamber 231 of the boom cylinder 230 can always maintain a predetermined constant pressure in the boom floating mode.

The second relief valve 284 may be installed on the fourth pressure-relief line 285d. The fourth pressure plunger 285d may have one end connected to one end of the second plunger line 285b and one end of the third plunger line 285c and the other end connected to the tank 206. [

This second relief valve 284 is set to a pressure such that the head chamber 231 of the boom cylinder 230 is maintained at a predetermined constant pressure.

That is, when the internal pressure of the head chamber 231 is lower than a preset constant pressure in the boom float mode, the second relief valve 284 is operated so that a separate pressure oil discharged from the gear pump 283, which will be described later, A separate pressurized fluid is not directly returned to the tank 206 through the fourth pressure fluid path 285d so that a constant pressure is maintained in the fourth pressure fluid path 285d, 231) is maintained at a predetermined constant pressure.

When the internal pressure of the head chamber 231 is higher than a predetermined pressure in the boom floating mode, the second relief valve 284 returns to the tank 206 through the fourth pressure line 285d. Of course.

As described above, according to the present embodiment, the floating control device 280 is configured to apply a preset pressure to the head chamber 231 of the boom cylinder 230, so that the weight of the boom 111, which can be received from the ground, It is possible to prevent the bucket 115 from being pinched into the ground due to the weight of the boom 111 even in a relatively smooth ground condition relative to the general ground, thereby facilitating the ground planing operation regardless of the condition of the ground surface And it is possible to secure a degree of freedom to implement the boom float function.

In addition, in the present embodiment, the load applied to the ground by the bucket 115 can be kept constant by using the floating control device 280, and a more complete planarization operation can be performed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art that various combinations and modifications may be made without departing from the scope of the present invention. Therefore, it should be understood that the technical contents related to the modifications and applications that can be easily derived from the embodiments of the present invention are included in the present invention.

100: Construction machine 110: Work machine
111: Boom 112: Boom cylinder
113: arm 114: arm cylinder
115: Bucket 116: Bucket cylinder
120: turning body 121: turning frame
123: cab 125: engine
127: Counter weight 130:
131: truck or track frame 133:
135: drive wheel 137: endless track
200: Boom floating system 201: Head side pressure roller
202: Rod side pressure line 204: Head side pressure return line
205: load side return line 206: tank
210: main pump 220: pilot pump
230: boom cylinder 231: head chamber
232: load chamber 233: safety valve
240: main control valve 250: remote control unit
260: valve for head 270: valve for rod
280: Floating control device 281: First relief valve
282: Check valve 283: Gear pump
284: second relief valve 285a: first pressure relief valve
285b: second pressure roller 285c: third pressure roller
285d: Fourth pressure turret 290: Engine

Claims

A main pump connected to the engine for driving a boom cylinder constituted by a head chamber and a load chamber; and a main control valve for controlling the operation of the boom cylinder,
A head valve for controlling pressure oil in the head chamber;
A rod valve for controlling pressure oil in the load chamber; And
And a floating control device for supplying a separate pressurized oil to the head chamber to maintain the head chamber at a predetermined constant pressure in a boom floating mode.

The apparatus according to claim 1,
A gear pump for discharging the pressure oil so that the head chamber maintains the preset constant pressure; And
And a relief valve installed on the pressure oil line connected to the tank between the gear pump and the head valve.

The apparatus according to claim 1,
A gear pump for discharging the pressure oil so that the head chamber maintains the preset constant pressure;
A check valve installed between the gear pump and the head valve;
A first relief valve installed on a pressure line connecting between the check valve and the head valve by a tank; And
And a second relief valve installed on a pressure line connecting the check valve and the gear pump to the tank.

4. The gear pump according to claim 2 or 3,
Wherein the boom is operated by receiving power from the engine.

The head valve according to claim 1,
A bidirectional flow port through which pressure fluid flows in both directions, the first port being in a floating function on state in the boom float mode; And
A bidirectional shut-off port for shutting off pressurized fluid, comprising a second port for bringing the floating function off state into a state.

2. The apparatus according to claim 1,
A bidirectional flow port through which pressure fluid flows in both directions, the first port being in a floating function on state in the boom float mode; And
A check valve type port for allowing the pressurized oil to flow into the tank, and a second port for bringing the floating function into the off state.