Construction machinery

Abstract

In the present invention, a frame upper space (14) is formed on a turning frame (5), the frame upper space being surrounded on the front, rear, right, and left sides by: a foot part (4A1) of a lower boom (4A) constituting a work device (4); an engine (7) serving as a motive power source; a cab (9); a cover member (10) serving as a right-side structure; a fuel tank (11); and a hydraulic oil tank (12). An accumulator (15) and a relief valve (20) are disposed in the frame upper space (14). Thereabove, the relief valve (20) is disposed at a higher position than a piping connection part (15A) of the accumulator (15).

Description

Technical Field

[0001] The present invention relates to construction machinery such as a hydraulic excavator equipped with an accumulator.

Background Art

[0002] A hydraulic excavator, which is a representative example of construction machinery, includes a self-propelled lower traveling body, an upper revolving body that is rotatably mounted on the lower traveling body, and a working device provided on the front side of the upper revolving body. The working device has a boom, an arm, and a bucket. The foot portion at the proximal end side of the boom is rotatably attached to the front side of the revolving frame.

[0003] The upper revolving body includes a revolving frame to which the foot portion of the working device is attached on the front side, a power source such as an engine or an electric motor provided on the rear side of the revolving frame for driving a hydraulic pump, a cab provided on the revolving frame and located on the left side of the foot portion, and a right-side structure provided on the revolving frame and located on the right side of the foot portion. The right-side structure is composed of, for example, a fuel tank, a hydraulic oil tank, a cover member for housing a control valve device, and the like.

[0004] Some hydraulic excavators are equipped with an accumulator connected to a hydraulic cylinder for storing hydraulic pressure (energy), a relief valve connected to the hydraulic oil tank, and a connecting pipe connecting the accumulator and the relief valve (Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] Incidentally, the upper rotating body of a hydraulic excavator is equipped with many hydraulic devices in addition to those mentioned above, and many hydraulic pipes are routed to connect these devices. Therefore, when retrofitting an accumulator or relief valve to the vehicle body, for example, the accumulator and relief valve must be installed in a location that avoids existing hydraulic devices and hydraulic pipes, or the hydraulic pipes must be routed to bypass them. For this reason, the hydraulic excavator described in Patent Document 1 has the problem that it is difficult to easily maintain or install the accumulator, relief valve, hydraulic pipes, etc., in a location that is easy to install, leading to reduced maintainability and increased installation costs.

[0007] The present invention has been made in view of the problems of the prior art described above, and the object of the present invention is to provide a construction machine that can improve maintainability and reduce installation costs by arranging an accumulator, relief valve, and hydraulic piping in appropriate positions.

[0008] The present invention comprises a self-propelled lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, and a working device provided on the front side of the upper rotating body and driven by a hydraulic cylinder, wherein the upper rotating body includes a rotating frame to which the foot portion of the working device is attached on the front side, a power source provided on the rear side of the rotating frame for driving a hydraulic pump, a cab located to the left of the foot portion and provided on the rotating frame, and a right-side structure located to the right of the foot portion and provided on the rotating frame, including a hydraulic oil tank for storing hydraulic oil supplied to the hydraulic pump, In a construction machine comprising an accumulator connected to the hydraulic cylinder, a relief valve connected to the hydraulic oil tank, and a connecting pipe connecting the piping connection portion of the accumulator to the relief valve, a frame space is formed on the slewing frame, enclosed on all sides by the foot portion of the work device, the power source, the cab, and the right-side structure, the accumulator and the relief valve are arranged in the frame space, and the relief valve is positioned higher than the piping connection portion of the accumulator.

[0009] According to the present invention, the accumulator, relief valve, and hydraulic piping can be positioned appropriately, thereby improving maintainability and reducing installation costs. [Brief explanation of the drawing]

[0010] [Figure 1] A left side view showing a wheeled hydraulic excavator applied to an embodiment of the present invention. [Figure 2] This is a perspective view showing the front portion of the upper rotating body with the cab omitted. [Figure 3] This is a cross-sectional view of the upper rotating body. [Figure 4] This is a magnified perspective view showing the area around the accumulator and relief valve. [Figure 5] This is a plan view showing a magnified view of the area around the accumulator and relief valve. [Figure 6] This is a perspective view showing the mounting structure of the accumulator to the right vertical plate. [Modes for carrying out the invention]

[0011] Hereinafter, a wheeled hydraulic excavator will be used as a representative example of a construction machine according to an embodiment of the present invention and will be described in detail with reference to Figures 1 to 6. In this embodiment, the description will be based on the front-rear and left-right directions as viewed from the operator seated in the driver's seat inside the cab.

[0012] In Figure 1, the hydraulic excavator 1 is a wheeled hydraulic excavator equipped with a self-propelled wheeled lower travel body 2 having left and right front wheels 2A and left and right rear wheels 2B (only the left side is shown). The hydraulic excavator 1 also includes an upper slewing body 3 that is rotatably mounted on the lower travel body 2, and a working device 4 provided on the front side of the upper slewing body 3.

[0013] The working device 4 is located on the front side of the upper slewing body 3. The working device 4 consists of a lower boom 4A whose base foot portion 4A1 is mounted vertically rotatably to the front side of the slewing frame 5 of the upper slewing body 3, an upper boom 4B mounted rotatably to the tip of the lower boom 4A, an arm 4C mounted rotatably to the tip of the upper boom 4B, a bucket 4D mounted rotatably to the tip of the arm 4C, and boom cylinders 4E, positioning cylinder 4F, arm cylinder 4G, and bucket cylinder 4H that drive (rotate) these lower boom 4A, upper boom 4B, arm 4C, and bucket 4D.

[0014] Although the work device 4 is equipped with a bucket 4D as an attachment (working tool), it is also possible to attach other attachments such as a grappler instead of the bucket 4D. Furthermore, instead of the boom of the work device consisting of two members, the lower boom 4A and the upper boom 4B, a boom consisting of one L-shaped bent member can also be used.

[0015] The slewing frame 5 is formed as a support structure that extends in the front-to-back direction while spreading out in the left-to-right direction. As shown in Figure 2, the slewing frame 5 is composed of a thick base plate 5A extending in the front-to-back direction, a left vertical plate 5B and a right vertical plate 5C erected on the base plate 5A and extending in the front-to-back direction at predetermined intervals in the left-to-right direction, a plurality of left overhang beams 5D extending to the left from the base plate 5A and the left vertical plate 5B, a plurality of right overhang beams (none of which are shown) extending to the right from the base plate 5A and the right vertical plate 5C, a left side frame 5E extending in the front-to-back direction at the tips of the plurality of left overhang beams 5D, and a right side frame (none of which is shown) extending in the front-to-back direction at the tips of the plurality of right overhang beams. The foot portion 4A1 of the lower boom 4A that constitutes the working device 4 is rotatably attached to the front of the left vertical plate 5B and the right vertical plate 5C.

[0016] As shown in FIG. 1, the counterweight 6 is provided at the rear part of the slewing frame 5. The counterweight 6 is configured as a weight for achieving weight balance with the working device 4.

[0017] The engine 7 as a power source is provided on the rear side of the slewing frame 5 (the front side of the counterweight 6). The engine 7 is disposed at the front side position of the counterweight 6 which is separated from the foot portion 4A1 of the lower boom 4A by a predetermined distance to the rear side. The engine 7 is configured as an internal combustion engine and is mounted in a horizontally disposed state extending in the left - right direction. Incidentally, as the power source, instead of the engine 7, an electric motor or a hybrid engine combining an engine and an electric motor can also be used.

[0018] The hydraulic pump 8 is attached, for example, to the left side of the engine 7 (shown by a dotted line in FIG. 1). Thereby, the hydraulic pump 8 is driven by the engine 7 to discharge the hydraulic oil from the hydraulic oil tank 12 described later as pressure oil.

[0019] The cab 9 is provided on the left front side on the slewing frame 5. The cab 9 is disposed on the left side of the foot portion 4A1 of the lower boom 4A, specifically, at the foremost part between the left vertical plate 5B and the left side frame 5E of the slewing frame 5. The cab 9 forms a driver's cab in which an operator rides inside. Inside the cab 9, a driver's seat on which the operator sits, a steering wheel for traveling, an operation lever for work, etc. (none of which are shown) are arranged.

[0020] As shown in FIGS. 2 and 3, the cover member 10 is provided on the right front side on the slewing frame 5. The cover member 10 has a hollow box structure, and inside, a control valve device for supplying and discharging pressure oil to various hydraulic actuators, tools for maintenance, etc. (none of which are shown) are accommodated. Further, the cover member 10 has a stepped upper surface 10A, and by stepping on this stepped upper surface 10A, it is possible to get on and off the upper slewing body 3.

[0021] The fuel tank 11 is located immediately behind the cover member 10 and is provided on the right side of the swing frame 5. The fuel tank 11 is formed as a rectangular parallelepiped container elongated in the vertical direction and stores fuel to be supplied to the engine 7 therein. Also, the upper surface 11A of the fuel tank 11 serves as a scaffold for an operator to ride on when performing maintenance work or the like.

[0022] The hydraulic oil tank 12 is located immediately behind the fuel tank 11 and is provided on the right side of the swing frame 5. Similar to the fuel tank 11, the hydraulic oil tank 12 is formed as a rectangular parallelepiped container elongated in the vertical direction and stores hydraulic oil to be supplied to the hydraulic pump 8 therein.

[0023] Here, the cover member 10, the fuel tank 11, and the hydraulic oil tank 12, which are arranged on the right side of the right vertical plate 5C of the swing frame 5 in front of the engine 7, constitute the right side structure. When an electric motor is used as the power source, the fuel tank 11 can be abolished and other structures, for example, a battery case for accommodating a battery for the electric motor, can be arranged.

[0024] The rear cover 13 is provided between the counterweight 6 and the hydraulic oil tank 12 so as to cover the engine 7, the hydraulic pump 8, etc. The front side portion of the upper surface 13A of the rear cover 13 serves as a scaffold for an operator to ride on when performing maintenance work or the like.

[0025] The frame upper space portion 14 is provided at the front side portion on the swing frame 5. Specifically, in the frame upper space portion 14, the foot portion 4A1 of the lower boom 4A constituting the working device 4 serves as the front wall, the engine 7 serves as the rear wall, the right side surface of the cab 9 serves as the left wall, and the left side surface of the right side structure composed of the cover member 10, the fuel tank 11, and the hydraulic oil tank 12 serves as the right wall. Thereby, the frame upper space portion 14 is formed as a rectangular space extending in the front-rear direction and surrounded by the front, rear, left, and right. In the frame upper space portion 14, an accumulator 15, a relief valve 20, a connection pipe 21, etc., which will be described later, are arranged.

[0026] The accumulator 15 is connected, for example, to the boom cylinder 4E, which acts as a hydraulic cylinder, via a relief valve 20 described later. The accumulator 15 is formed as a cylindrical container with pressure resistance and is arranged in a vertical position extending in the vertical direction. The accumulator 15 is located slightly to the right of the upper space portion 14 of the frame and is positioned lower than the upper surface 11A of the fuel tank 11, which constitutes the right-side structure. More specifically, the accumulator 15 is located to the left of the right vertical plate 5C of the slewing frame 5, and is positioned between the axis position when the foot portion 4A1 of the lower boom 4A is rotatably attached to the left vertical plate 5B and the right vertical plate 5C, and the upper surface 11A of the fuel tank 11. As a result, the accumulator 15 does not obstruct the view of the operator when looking to the right inside the cab 9, improves the appearance of the upper slewing body 3, and does not get in the way when workers move on the upper surface 11A of the fuel tank 11 or the upper surface 13A of the rear cover 13, which serve as footing.

[0027] On the other hand, a pipe connection section 15A is provided at the bottom of the accumulator 15. This pipe connection section 15A consists of a hose fitting called an elbow, in which the mounting direction to the bottom surface of the accumulator 15 and the connection port 15A1 to which the connecting pipe 21 is connected are positioned at a right angle. As shown in Figures 3 and 6, the pipe connection section 15A is installed so that the connection port 15A1 faces the opposite side of the relief valve 20, and in this embodiment, the front side.

[0028] The accumulator 15 can store the pressure (energy) of the hydraulic fluid (pressurized oil) discharged by the boom cylinder 4E by allowing it to flow into its interior. On the other hand, the accumulator 15 can reduce the shaking of the work device 4 during travel by controlling the flow rate of the pressurized oil flowing in from the boom cylinder 4E.

[0029] The bracket support member 16 is located near the rear of the lower boom 4A and is attached to the right side of the right vertical plate 5C. The bracket support member 16 consists of a long, thick plate extending upward from the right side of the right vertical plate 5C. An upper support portion 16A is provided on the upper part of the bracket support member 16, protruding to the left, to which the upper part of the accumulator mounting bracket 18 is attached. Furthermore, a lower support portion 17 is provided extending upward from the left side of the right vertical plate 5C, directly below the upper support portion 16A, to which the lower part of the accumulator mounting bracket 18 is attached.

[0030] The accumulator mounting bracket 18 is formed as a plate facing the bracket support member 16 at a predetermined distance in the left-right direction. The upper part of the accumulator mounting bracket 18 is attached to the upper support part 16A, and the lower part is attached to the lower support part 17. Furthermore, the accumulator 15 is attached to the left side of the accumulator mounting bracket 18 in a state where it extends in the vertical direction.

[0031] The insertion space 19 is formed between the bracket support member 16 and the accumulator mounting bracket 18. As shown in Figure 4, the insertion space 19 is a space for inserting multiple hydraulic pipes 24-27, which will be described later. This allows the multiple hydraulic pipes 24-27 to be routed in a short and simple manner without having to detour around the accumulator 15.

[0032] The relief valve 20 is located towards the rear of the frame space 14 and is connected to the hydraulic fluid tank 12. The relief valve 20 opens when the pressure of the hydraulic fluid returned from the boom cylinder 4E is higher than a preset pressure, and discharges the hydraulic fluid into the hydraulic fluid tank 12. As shown in Figure 5, the relief valve 20 is located behind the accumulator 15 and offset to the left of the accumulator 15.

[0033] As shown in Figure 3, the relief valve 20 is positioned higher by dimension H than the piping connection portion 15A of the accumulator 15. This allows air to enter the hydraulic circuit when the accumulator 15 is installed, but this air can be discharged into the hydraulic fluid tank 12 from the relief valve 20, which is positioned higher than the piping connection portion 15A of the accumulator 15, when the ride control system described later is activated. In other words, the air bleeding procedure when forming the ride control system can be omitted.

[0034] The connecting pipe 21 connects the pipe connection part 15A of the accumulator 15 to the relief valve 20. The connecting pipe 21 is made of a pressure-resistant hose that is strong enough to withstand the high pressure of pressurized oil and can be bent. One end of the connecting pipe 21 is connected to the relief valve 20, and the other end is connected to the connection port 15A1 of the pipe connection part 15A.

[0035] Here, because the pressure-resistant hose has a multi-layer structure to withstand high pressure, its bending radius becomes large. Therefore, the relative positions of the accumulator and the relief valve are limited to positions that can be connected by connecting piping made of pressure-resistant hose, taking into account the bending radius of the connecting piping. Consequently, the accumulator and the relief valve cannot be placed close together.

[0036] In contrast, the connecting pipe 21 of this embodiment extends from the relief valve 20 toward the accumulator 15 and is connected to the connection port 15A1 of the pipe connection section 15A at a position that passes to the left of the accumulator 15. This makes it possible to increase the distance from the relief valve 20 to the connection port 15A1 of the pipe connection section 15A. In other words, the accumulator 15 and the relief valve 20 can be placed in close proximity to each other while keeping the bending radius of the connecting pipe 21 the same.

[0037] The ride control system will now be described. The ride control system is a system that reduces vibrations during travel by actively moving the work device 4 while it is traveling, thereby reducing spillage from the bucket 4D and operator fatigue. The ride control system connects the hydraulic circuit on the bottom side of the boom cylinder 4E that supports the work device 4 to the accumulator 15, and the hydraulic circuit on the rod side of the boom cylinder 4E to the drain (hydraulic oil tank 12), so that vibrations caused by the up and down movement of the work device 4 due to uneven ground can be mitigated by the accumulator 15.

[0038] The ride control system consists of an accumulator 15, a relief valve 20, a bottom-side valve 22 connected to the bottom side of the boom cylinder 4E, a rod-side valve 23 connected to the rod side of the boom cylinder 4E (see Figure 5), and the like.

[0039] The hydraulic pipes 24-27 are connected to the control valve device inside the cover member 10. The hydraulic pipes 24-27 are made of metal piping or pressure-resistant hoses. The hydraulic pipes 24-27 extend in the front-rear direction through the insertion space 19 between the bracket support member 16 and the accumulator mounting bracket 18. Because the hydraulic pipes 24-27 are inserted through the insertion space 19, there is no need to bypass the accumulator 15, so they can be made short and routed with a simple fixing structure.

[0040] The hydraulic excavator 1 according to this embodiment has the configuration described above, and its operation will now be explained.

[0041] The operator boards the cab 9, sits in the driver's seat, and starts the engine 7. In this state, the operator can move the lower vehicle 2 by operating the steering wheel and other controls. The operator can also operate the work levers and other controls to rotate the upper slewing body 3 and perform earth excavation work with the work device 4.

[0042] Here, when the work device 4 is traveling with soil being excavated by its bucket 4D, the ride control system is activated. This ride control system can mitigate vibrations of the work device 4 by releasing and discharging pressurized oil between the boom cylinder 4E and the accumulator 15 when the lower boom 4A of the work device 4 moves up and down due to uneven ground.

[0043] Thus, according to this embodiment, a frame space 14 is formed on the slewing frame 5, surrounded on all sides by the foot portion 4A1 of the lower boom 4A constituting the working device 4, the engine 7 as a power source, the cab 9, the cover member 10 as a right-side structure, the fuel tank 11, and the hydraulic oil tank 12. The accumulator 15 and the relief valve 20 are arranged in the frame space 14. Furthermore, the relief valve 20 is positioned higher than the piping connection portion 15A of the accumulator 15.

[0044] Therefore, the accumulator 15 and the relief valve 20 can be positioned in an appropriate location such that the relief valve 20 is higher than the piping connection portion 15A of the accumulator 15. As a result, even if air is mixed into the hydraulic circuit when the accumulator 15 is installed, this air can be discharged into the hydraulic fluid tank 12 from the relief valve 20, which is positioned higher than the piping connection portion 15A of the accumulator 15, when the ride control system is started. Consequently, the air bleeding work when forming the ride control system can be omitted, improving maintainability and reducing installation costs.

[0045] Furthermore, the piping connection portion 15A of the accumulator 15 is positioned with the connection port 15A1 facing forward, opposite to the relief valve 20, and the connecting pipe 21 extends forward from the relief valve 20 toward the accumulator 15, passing to the side of the accumulator 15 before connecting to the connection port 15A1.

[0046] Therefore, even when connecting the accumulator 15 and the relief valve 20 with a connecting pipe 21 made of a pressure-resistant hose that cannot reduce its bending radius, the distance between the connection points of the connecting pipe 21 can be increased while keeping the bending radius of the connecting pipe 21 the same. As a result, the accumulator 15 and the relief valve 20 can be placed in close proximity to each other while keeping the bending radius of the connecting pipe 21 the same. Consequently, the accumulator 15 and the relief valve 20 can be installed in locations that are easy to maintain and easy to install, thereby improving maintainability and reducing installation costs.

[0047] Furthermore, the slewing frame 5 is erected with a gap in the left-right direction and extends in the front-rear direction, and has a left vertical plate 5B and a right vertical plate 5C to which the foot portion 4A1 of the lower boom 4A constituting the work device 4 is attached. The right vertical plate 5C is provided with a bracket support member 16 extending upward and an accumulator mounting bracket 18 attached to the bracket support member 16 and to which the accumulator 15 is attached. Between the bracket support member 16 and the accumulator mounting bracket 18, an insertion space 19 is formed for inserting hydraulic pipes 24-27. As a result, the multiple hydraulic pipes 24-27 are inserted into the insertion space 19, eliminating the need to bypass the accumulator 15, allowing them to be made shorter and routed with a simple fixing structure. In this respect as well, maintainability can be improved and installation costs can be reduced.

[0048] In the embodiments described, a wheeled hydraulic excavator 1 was used as an example of construction machinery. However, the present invention is not limited to this and can be broadly applied to other construction machinery, such as crawler-type hydraulic excavators. [Explanation of symbols]

[0049] 1. Hydraulic excavator (construction machinery) 2 Lower running body 3. Upper rotating body 4. Working equipment 4A Lower boom (boom) 4A1 Foot section 4E Boom Cylinder (Hydraulic Cylinder) 5. Swivel Frame 5A bottom plate 5B Left vertical board 5C Right vertical board 7. Engine (power source) 8. Hydraulic pump 9 Cab 10 Cover component (right-side structure) 11 Fuel tank (right side structure) 12 Hydraulic oil tank (right side structure) 14. Upper space of the frame 15 Accumulator 15A Pipe connection 15A1 connection port 16 Bracket support member 18. Accumulator mounting bracket 19 Insertion space 20 Relief Valves 21 Connecting pipes 24-27 Hydraulic piping

Claims

1. It consists of a self-propelled lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, and a working device provided on the front side of the upper rotating body and driven by a hydraulic cylinder. The upper rotating body is A slewing frame to which the foot portion of the work device is attached on the front side, A power source for driving a hydraulic pump is provided on the rear side of the aforementioned slewing frame, A cab is located to the left of the foot section and mounted on the swivel frame, A right-side structure located to the right of the foot portion and mounted on the slewing frame, including a hydraulic fluid tank for storing hydraulic fluid supplied to the hydraulic pump, An accumulator connected to the hydraulic cylinder, A relief valve connected to the aforementioned hydraulic fluid tank, A connecting pipe that connects the piping connection part of the accumulator and the relief valve, In a construction machine equipped with, On the aforementioned slewing frame, a frame space is formed that is enclosed on all sides by the foot portion of the work device, the power source, the cab, and the right-side structure. The accumulator and the relief valve are arranged in the space above the frame. The construction machine is characterized in that the relief valve is positioned higher than the piping connection portion of the accumulator.

2. In the construction machine described in claim 1, The piping connection portion of the accumulator is positioned such that the connection port faces away from the relief valve. The construction machine is characterized in that the connecting pipe extends from the relief valve toward the accumulator and is connected to the connection port at a position where it passes beside the accumulator.

3. In the construction machine described in claim 1, The aforementioned swivel frame is erected with a gap in the left-right direction and extends in the front-rear direction, and has a left vertical plate and a right vertical plate to which the foot portion of the work device is attached. The right vertical plate is provided with a bracket support member extending upward and an accumulator mounting bracket attached to the bracket support member and to which the accumulator is attached. A construction machine characterized in that a passage space for inserting hydraulic piping is formed between the bracket support member and the accumulator mounting bracket.

4. In the construction machine described in claim 1, The work device includes a boom having the foot portion, The hydraulic cylinder includes a boom cylinder that drives the boom, The construction machine is characterized in that the accumulator is connected to the boom cylinder.

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