JP7309514B2 - construction machinery - Google Patents

Description

The present invention relates to construction machinery.

Patent Literature 1 discloses a hydraulic circuit provided with a variable displacement pump whose discharge amount can be changed. In this hydraulic circuit, the variable displacement pump is provided with a discharge amount changing member, and the discharge amount from the variable displacement pump changes as the operating state of the discharge amount changing member changes. Further, the hydraulic circuit is provided with a switching valve such as an electromagnetic valve. By switching the operating state of the switching valve, the state of oil supply to the discharge amount changing member is switched, and the operating state of the discharge amount changing member is changed.

JP-A-11-22632

A hydraulic circuit including a variable displacement pump and a switching valve as described above is sometimes mounted on a construction machine such as a hydraulic excavator. In construction machines equipped with hydraulic circuits such as those described above, there is a demand for miniaturization of pump assemblies equipped with variable displacement pumps. In addition, there is a demand for easy maintenance of pumps such as variable displacement pumps provided in pump assemblies.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to mount a hydraulic circuit having a variable displacement pump and a switching valve, to realize a compact pump assembly, and to To provide a construction machine whose variable pump can be easily maintained.

In order to achieve the above object, a construction machine according to one aspect of the present invention provides a pump assembly including a variable displacement pump whose discharge amount is variable; A switching valve for changing, comprising a switching valve provided separately from the pump assembly at a position separate from the pump assembly, and a door that can be opened and closed, and visible from the outside through a portion where the door is opened a cover forming a pump chamber in which the pump assembly and the switching valve are arranged in a wide field of view .

According to the present invention, it is possible to provide a construction machine that is equipped with a hydraulic circuit that includes a variable displacement pump and a switching valve, achieves miniaturization of the pump assembly, and facilitates maintenance of the variable displacement pump.

FIG. 1 is a schematic diagram showing a hydraulic excavator according to the first embodiment. FIG. 2 is a perspective view showing the configuration of a cover of an upper revolving body and its vicinity in the hydraulic excavator according to the first embodiment. FIG. 3 is a perspective view showing the configuration of a pump chamber and an engine room formed inside the cover of the upper revolving body in the hydraulic excavator according to the first embodiment. FIG. 4 is a perspective view showing the configuration of the pump chamber of the upper revolving body in the hydraulic excavator according to the first embodiment. FIG. 5 is a schematic diagram showing an example of a hydraulic circuit including a pump assembly and a switching valve mounted on the hydraulic excavator according to the first embodiment;

An embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

FIG. 1 shows a hydraulic excavator 1 as a construction machine according to a first embodiment. As shown in FIG. 1 , the hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 provided vertically above the lower traveling body 2 (arrow Z1 side). The upper revolving body 3 is rotatable with respect to the lower traveling body 2 about a revolving shaft parallel or substantially parallel to the vertical direction (directions indicated by arrows Z1 and Z2).

In each of the lower traveling structure 2 and the upper swing structure 3, a front-rear direction (perpendicular or substantially perpendicular) that intersects the vertical direction and a width direction that intersects both the vertical direction and the front-rear direction are defined. . In FIG. 1 , the directions indicated by arrows X1 and X2 match the longitudinal direction of the upper rotating body 3 , and the direction perpendicular to the paper surface matches the width direction of the upper rotating body 3 . 1 shows the upper revolving body 3 as viewed from one side in the width direction, and the upper revolving body 3 as viewed from the right side. In addition, in FIG. 1 , the front side (the arrow X1 side) of the upper rotating body 3 coincides or substantially coincides with the front side of the lower traveling body 2 . Therefore, in FIG. 1, the undercarriage 2 is shown as viewed from one side in the width direction, that is, from the right side.

A working device 5 is connected to the upper revolving body 3 . The work device 5 revolves with respect to the lower traveling body 2 together with the upper revolving body 3 . The working device 5 has a boom 6 , an arm 7 and a bucket 8 . A base end of the boom 6 is rotatably attached to the upper revolving body 3 . The boom hoisting cylinder 6</b>A is operated to rotate the boom 6 with respect to the upper rotating body 3 , and the boom 6 is raised or lowered with respect to the upper rotating body 3 . The base end of the arm 7 is rotatably attached to the tip of the boom 6 . By operating the arm raising/lowering cylinder 7A, the arm 7 rotates with respect to the boom 6, and the arm 7 raises or lowers with respect to the boom 6. As shown in FIG. Bucket 8 is a type of attachment and is detachably attached to the tip of arm 7 . Further, the bucket 8 is rotatable with respect to the arm 7 when the bucket 8 is attached to the tip of the arm 7 . The bucket 8 rotates with respect to the arm 7 by operating the attachment operating cylinder 8A. As described above, by operating the boom 6 , the arm 7 and the bucket 8 , the bucket 8 of the hydraulic excavator 1 excavates earth and sand. In this embodiment, the central plane of the upper swing body 3 in the width direction (horizontal direction) passes through the work device 5 (boom 6).

The upper revolving body 3 has a frame 10 . The frame 10 is provided at the lower end of the upper revolving body 3 in the vertical direction. In addition, in the upper swing body 3, the frame 10 is formed from the front end to the rear end. In the upper revolving body 3, the frame 10 is formed from one end to the other end in the width direction, that is, from the left end to the right end. In addition, in the upper revolving body 3, a cab (cab) 11 is installed on the frame 10. As shown in FIG. The cab 11 is installed side by side with the boom 6 in the width direction. The operator operates the hydraulic excavator 1 inside the cab 11 . In the upper swing body 3 of the present embodiment, the cab 11 is arranged side by side on the left side with respect to the boom 6 (working device 5).

A counterweight 19 is installed on the frame 10 of the upper swing body 3 . On the upper swing structure 3 the counterweight 19 is arranged on the frame 10 at the rear end. A cover 12 is installed on the frame 10 of the upper swing body 3 . In the upper swing structure 3, the cover 12 is arranged on the rear side (arrow X2 side) with respect to the boom 6 and the cab 11. As shown in FIG. The cover 12 also includes doors 13 and 15 that can be opened and closed. In this embodiment, the central plane of the upper rotating body 3 in the width direction (horizontal direction) passes through the door 15 . In the upper revolving body 3, the door (first door) 13 is arranged adjacent to the door (second door) 15 in the width direction. In the upper revolving body 3 of this embodiment, the door 13 is adjacent to the door 15 on the right side.

FIG. 2 shows the configuration of the cover 12 and its vicinity. In FIG. 2 , the directions indicated by arrows Y1 and Y2 are the width directions of the upper revolving body 3 . As shown in FIG. 2 and the like, a pump chamber 16 and an engine room 17 are formed inside the cover 12 . In the upper revolving body 3, the cover 12 covers the space in which the pump chamber 16, the engine room 17, etc. are formed from the vertical upper side and both sides (left side and right side) in the width direction. Therefore, the pump chamber 16, the engine room 17, and the like are formed between the upper wall of the frame 10 and the cover 12 in the vertical direction. In the upper swing body 3, the space in which the pump chamber 16, the engine room 17, etc. are formed is arranged on the rear side (arrow X2 side) with respect to the boom 6 and the cab 11. As shown in FIG. In the upper rotating body 3, when the doors 13 and 15 are closed, the doors 13 and 15 are adjacent to the space in which the pump chamber 16 and the engine room 17 are formed on the rear side. .

3 shows the configuration of the pump chamber 16 and the engine room 17, and FIG. 4 shows the configuration of the pump chamber 16. As shown in FIG. As shown in FIGS. 2 to 4 and the like, inside the cover 12, an engine room 17 is formed within a visual range visible from the outside of the cover 12 through a portion where the door (second door) 15 is opened. Inside the cover 12, a pump chamber 16 is formed within a visual range visible from the outside of the cover 12 through a portion where the door (first door) 13 is opened. Therefore, the center plane of the upper swing body 3 in the width direction (horizontal direction) passes through the engine room 17 . In the upper swing body 3, the pump chamber 16 is arranged adjacent to the engine room 17 in the width direction. In the upper revolving body 3 of the present embodiment, the pump chamber 16 is adjacent to the engine room 17 on the right side (arrow Y1 side). An engine 18 is arranged in the engine room 17 .

A pump assembly 21 is arranged in the pump chamber 16 . A switching valve 22 is arranged in the pump chamber 16 . The switching valve 22 is, for example, an electromagnetic valve such as a solenoid valve. The switching valve 22 is formed separately from the pump assembly 21 and arranged apart from the pump assembly 21 in the pump chamber 16 . However, the pump assembly 21 and the switching valve 22 are arranged in the pump chamber 16 and are arranged in a visual range visible from the outside of the cover 12 through the portion where the door 13 is opened. Therefore, the distance between the pump assembly 21 and the switching valve 22 does not become excessively large.

A main fuel filter 23 , a pilot filter 24 and a pre-fuel filter 25 are arranged in the pump chamber 16 . A pilot filter 24 is provided in a hydraulic circuit including the pump assembly 21, the switching valve 22, and the like. The pilot filter 24 prevents dust from remaining in narrow flow passages, constrictions, and the like in the hydraulic circuit, and also prevents wear of equipment arranged in the hydraulic circuit. The main fuel filter 23 removes contaminants mixed in and generated in the fuel. This prevents the life of the engine 18 from being shortened. The pre-fuel filter 25 removes foreign matter and water in the fuel. As a result, rusting of the engine 18 is prevented, and a decrease in output of the engine 18 is prevented.

In the pump chamber 16, the switching valve 22 is arranged in the vertically upper portion. Also, in the pump chamber 16 , the switching valve 22 is arranged vertically above the pump assembly 21 . The switching valve 22 is arranged vertically above the main fuel filter 23 , the pilot filter 24 and the pre-fuel filter 25 . Here, each of the main fuel filter 23 , the pilot filter 24 and the pre-fuel filter 25 is a component that requires maintenance more frequently than the switching valve 22 .

A connection is made between pump assembly 21 and switching valve 22 via one or more hoses, including hose 26 . In addition, in the upper revolving body 3, the tank 37 is provided adjacent to the front side (arrow X1) of the pump chamber 16. As shown in FIG. Oil is stored in the tank 37 . Further, the pump assembly 21 is provided with a connector portion 28 . A connection pipe (not shown) extending from the tank 37 is connected to the connector portion 28 . Also, the connector portion 28 is connected to the switching valve 22 via the hose 27 . One end of a hose 29 is connected to the switching valve 22 and the other end of the hose 29 is connected to the pump assembly 21 .

FIG. 5 shows an example of a hydraulic circuit including the pump assembly 21 and switching valve 22 described above. As shown in FIG. 5 , the hydraulic circuit includes the aforementioned tank 37 in addition to the pump assembly 21 and switching valve 22 . The pump assembly 21 includes a variable displacement pump 31 and a pump 32 . Further, the displacement variable pump 31 is provided with a discharge amount changing member 34 . As the operating state of the discharge amount changing member 34 changes, the discharge amount from the variable displacement pump 31 changes. Further, the hydraulic circuit is provided with discharge passages 33A and 33B through which oil is discharged from the variable displacement pump 31 . Oil discharged from the displacement variable pump 31 is supplied to each of the actuators of the hydraulic excavator 1 through a corresponding one of the discharge flow paths 33A and 33B. The actuators of the hydraulic excavator 1 include the boom hoisting cylinder 6A, the arm hoisting cylinder 7A, and the attachment operating cylinder 8A, as well as a swing motor (not shown). By operating the turning motor, the upper turning body 3 turns with respect to the lower traveling body 2 .

A drain passage 46 is also provided in the hydraulic circuit. A return filter 45 is arranged in the drain channel 46 . Oil from the aforementioned actuators is discharged to tank 37 through drain passage 46 .

The hydraulic circuit is also provided with a suction flow path 38 that connects between the tank 37 and the variable displacement pump 31 . While the variable displacement pump 31 is operating, a suction force is generated in the suction flow path 38 from the tank 37 toward the variable displacement pump 31 . Therefore, oil flows into the variable displacement pump 31 from the tank 37 while the variable displacement pump 31 is in operation. Then, the variable displacement pump 31 discharges the oil that has flowed through the suction flow path 38 to the discharge flow paths 33A and 33B. Suction channel 38 comprises a conduit portion 41 and a port portion 42 . The conduit portion 41 is formed in the aforementioned connecting pipe (not shown) connecting between the tank 37 and the pump assembly 21 . Port portion 42 is also formed in connector portion 28 of pump assembly 21 .

The hydraulic circuit is also provided with a supply channel 35 for supplying oil to the switching valve 22 and a drain channel 43 for discharging oil from the switching valve 22 . A pilot flow path 36 connecting between the switching valve 22 and the discharge amount changing member 34 is provided in the hydraulic circuit. A supply channel 35 is formed through the interior of the hose 26 described above. A drain channel (first drain channel) 43 is formed through the inside of the hose 27 described above. A pilot flow path 36 is formed through the interior of the hose 29 described above. One end of the drain channel (first drain channel) 43 is connected to the switching valve 22 . The end of the drain channel 43 opposite to the switching valve 22 is connected to the suction channel 38 between the tank 37 and the variable displacement pump 31 . The drain channel 43 is connected to the suction channel 38 at a port portion 42 formed in the connector portion 28 of the pump assembly 21 . Therefore, a suction force directed toward the suction channel 38 is generated in the drain channel 43 .

The switching valve 22 is, for example, an electromagnetic valve, as described above, and the operating state of the switching valve 22 is switched by switching whether power is supplied to the switching valve 22 or not. The switching valve 22 is switchable between a first operating state and a second operating state. In the first operating state of the switching valve 22 , the supply channel 35 communicates with the pilot channel 36 and the drain channel 43 does not communicate with the pilot channel 36 in the switching valve 22 . Therefore, in the first operating state of the switching valve 22 , oil discharged from the pump 32 is supplied to the discharge amount changing member 34 through the supply flow path 35 and the pilot flow path 36 . By supplying oil to the discharge amount changing member 34, the amount of discharge from the variable displacement pump 31 is reduced compared to the state where the oil is not supplied to the discharge amount changing member 34.

On the other hand, in the second operating state of the switching valve 22 , the drain channel 43 communicates with the pilot channel 36 and the supply channel 35 does not communicate with the pilot channel 36 in the switching valve 22 . Therefore, in the second operating state of the switching valve 22 , a suction force directed toward the suction flow path 38 is generated in the pilot flow path 36 and the drain flow path 43 . Therefore, in the second operating state of the switching valve 22, oil is discharged from the discharge amount changing member 34 through the pilot flow path 36 and the drain flow path 43 to the suction flow path 38, and oil is not supplied to the discharge amount changing member 34. .

In the hydraulic excavator 1 of the present embodiment, the switching valve 22 is provided separately from the pump assembly 21 including the displacement variable pump 31 and arranged at a position separated from the pump assembly 21 . Since the switching valve 22 is not integrated with the pump assembly 21, miniaturization of the pump assembly 21 is easily achieved. In addition, due to the miniaturization of the pump assembly 21, a space for maintaining the variable displacement pump 31, the pump 32, etc. in the pump chamber 16 is appropriately secured. This facilitates maintenance of the pumps provided in the pump assembly 21 such as the variable displacement pump 31 and the pump 32 .

Further, in this embodiment, the pump assembly 21 and the switching valve 22 are arranged in the pump chamber 16 and are arranged in a visual range visible from the outside of the cover 12 through the open portion of the door 13 . Therefore, the distance between the pump assembly 21 and the switching valve 22 does not become excessively large. Therefore, in the control of the discharge amount from the variable displacement pump 31 by the switching valve 22, deterioration of responsiveness is effectively prevented. Also, since the distance between the pump assembly 21 and the switching valve 22 does not become excessively long, the hose (for example, 26, 27, 29, etc.) connecting between the pump assembly 21 and the switching valve 22 does not become excessively long. It is possible to reduce the space occupied by the hose.

Further, in the present embodiment, the switching valve 22 is arranged in the vertically upper portion of the pump chamber 16 . Therefore, parts (devices) that require more frequent maintenance than the switching valve 22, such as the main fuel filter 23, the pilot filter 24, and the pre-fuel filter 25, can be placed vertically below the pump chamber 16. becomes.

Also, in this embodiment, the drain flow path 43 from the switching valve 22 is connected to the suction flow path 38 between the tank 37 and the variable displacement pump 31 . Therefore, when the drain channel 43 communicates with the pilot channel 36 in the switching valve 22 , a suction force directed toward the suction channel 38 is generated in the pilot channel 36 and the drain channel 43 . Therefore, in a state in which the drain flow path 43 communicates with the pilot flow path 36 in the switching valve 22, the oil is appropriately discharged from the discharge amount changing member 34 to the suction flow path 38 through the pilot flow path 36 and the drain flow path 43. . As a result, reverse flow of oil in the drain passage 43 and the pilot passage 36 is effectively prevented, and erroneous operation of the discharge amount changing member 34 is effectively prevented.

In this embodiment, the drain channel (first drain channel) 43 is connected to the suction channel 38 as described above, and the drain channel (second drain channel) from the actuator to the tank 37 is connected. 46 is not connected to the region upstream of the return filter 45 . Therefore, even if a large back pressure is generated in the drain channel 46 by the return filter 45 , the drain channel 43 is hardly affected by the back pressure generated in the drain channel 46 . Therefore, reverse flow of oil in the drain passage 43 and the pilot passage 36 is more effectively prevented, and malfunction of the discharge amount changing member 34 is more effectively prevented.

Also in this embodiment, the drain channel 43 is connected to the suction channel 38 at a port portion 42 formed in the pump assembly 21 . That is, the drain channel 43 is connected to a portion of the suction channel 38 that is close to the variable displacement pump 31 . As described above, the suction flow path 38 generates a suction force from the tank 37 toward the variable displacement pump 31 . Therefore, by connecting the suction flow path 38 to a portion near the variable displacement pump 31 in the suction flow path 38, the discharge amount changing member From 34 , the oil is more appropriately discharged to suction channel 38 through pilot channel 36 and drain channel 43 .

In the above-described embodiments and the like, the hydraulic circuit including the pump assembly 21 and the switching valve 22 is mounted on the hydraulic excavator, but it is not limited to this. In one example, a construction machine other than a hydraulic excavator, such as a crane, may be equipped with a hydraulic circuit similar to the hydraulic circuit described above.

It should be noted that the present invention is not limited to the above-described embodiments, and can be variously modified in the implementation stage without departing from the gist of the present invention. Further, each embodiment may be implemented in combination as appropriate, in which case the combined effect can be obtained. Furthermore, various inventions are included in the above embodiments, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and effects can be obtained, the configuration with the constituent elements deleted can be extracted as an invention.

DESCRIPTION OF SYMBOLS 1... Hydraulic excavator, 2... Lower running body, 3... Upper revolving body, 5... Working device, 12... Cover, 13, 15... Door, 16... Pump chamber, 21... Pump assembly, 22... Switching valve, 31... Capacity Variable pump 34 Discharge amount changing member 35 Supply channel 36 Pilot channel 37 Tank 38 Suction channel 41 Pipe line portion 42 Port portion 43 Drain channel (second 1 drain channel).

Claims (3)

a pump assembly comprising a variable displacement pump capable of varying the discharge volume;
a switching valve that changes the amount of discharge from the variable displacement pump by switching an operating state, the switching valve being provided separately from the pump assembly at a position separate from the pump assembly;
a cover comprising a door that can be opened and closed, and forming a pump chamber in which the pump assembly and the switching valve are arranged within a visual range visible from the outside through the portion where the door is open;
A construction machine comprising: 2. The construction machine according to claim 1 , wherein said switching valve is arranged at a vertically upper portion in said pump chamber. a tank for storing oil,
a suction flow path connecting between the tank and the variable displacement pump and allowing the oil to flow from the tank to the variable displacement pump;
a drain channel having one end connected to the switching valve for discharging the oil from the switching valve, the end opposite to the switching valve being connected to the suction channel;
3. The construction machine of claim 1 or 2 , further comprising: