Combination valve for increasing speed of excavator and excavator

Abstract

The utility model discloses a speed increasing combination valve for an excavator and the excavator. The combination valve comprises a bucket rod bypass valve, a bucket bypass valve and a movable arm bypass valve. The bucket rod bypass valve, the bucket bypass valve and the movable arm bypass valve are the same in structure and each comprise a closed position, a through position, a hydraulic end opening, a first through opening and a second through opening, and the normal state is the closed position. Two-way ports of the bucket rod bypass valve, the bucket bypass valve and the movable arm bypass valve are all communicated with the oil tank; one port of the bucket rod bypass valve is connected with a bucket rod adjustable throttle valve; one port of the bucket bypass valve is connected with a bucket adjustable throttle valve; and one port of the movable arm bypass valve is connected with a movable arm adjustable throttle valve. After the combination valve is connected, the working speed of the excavator can be increased, the oil return resistance of hydraulic oil is reduced after the combination valve is installed, the speed of the excavator can be controlled due to the existence of the adjustable throttling valve, and the power consumption of an engine and a hydraulic pump is not increased.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a combined valve for increasing the speed of an excavator and the excavator. Background Art

[0002] Hydraulic excavators play an important role in various types of engineering construction, and there are huge numbers of them in society. Improving the speed of hydraulic excavators allows them to do more work in the same amount of time, which can provide better services for excavator users and make great contributions to social development.

[0003] At present, the main way to improve the working efficiency of excavators is to increase the displacement of the hydraulic pump or increase the power of the engine. This improves the working efficiency but also increases energy consumption.

[0004] The combination valve involved in this patent mainly reduces the resistance of the hydraulic oil circuit without increasing energy input, and increases the speed of the excavator while ensuring that its speed is adjustable. The combination valve involved in this patent is connected to the hydraulic system of the excavator. After debugging, the working speed of the excavator can be increased, which can better meet customer needs. Summary of the invention

[0005] In view of the above-mentioned defects in the prior art, the purpose of the utility model is to provide a combined valve for increasing the speed of an excavator and an excavator.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] On the one hand, the utility model provides a combined valve for hoisting speed of an excavator, including a boom bypass valve, a bucket bypass valve, and a boom bypass valve;

[0008] The arm bypass valve, bucket bypass valve and boom bypass valve have the same structure and include a closed position, an open position, a hydraulic port, a single port and a double port, and the normal state is the closed position;

[0009] The two ports of the arm bypass valve, the bucket bypass valve and the boom bypass valve are all connected to the oil tank;

[0010] One port of the boom bypass valve is connected to a boom adjustable flow valve;

[0011] One port of the bucket bypass valve is connected to a bucket adjustable flow valve;

[0012] One port of the boom bypass valve is connected with a boom adjustable flow valve.

[0013] In a second aspect, the utility model provides an excavator, comprising a platform, a boom, a dipper arm, and a bucket which are hinged in sequence;

[0014] It also includes a boom cylinder, a dipper rod cylinder, and a bucket cylinder; the boom cylinder is connected to the boom and the platform respectively, the dipper rod cylinder is connected to the dipper rod and the boom respectively, and the bucket cylinder is connected to the bucket and the dipper rod respectively;

[0015] It also includes a boom reversing valve, a bucket reversing valve, and a boom reversing valve; the boom reversing valve is connected to the boom cylinder, the bucket reversing valve is connected to the bucket cylinder, and the boom reversing valve is connected to the boom cylinder;

[0016] It also includes a boom pilot valve, a bucket pilot valve, and a boom pilot valve; the boom pilot valve is connected to the control end of the boom reversing valve, the bucket pilot valve is connected to the control end of the bucket reversing valve, and the boom pilot valve is connected to the control end of the boom reversing valve;

[0017] It also includes a combined valve for lifting speed for an excavator as described in one aspect;

[0018] The hydraulic port of the arm bypass valve is communicated with the arm pilot valve, the hydraulic port of the bucket bypass valve is communicated with the bucket pilot valve, and the hydraulic port of the boom bypass valve is communicated with the boom pilot valve;

[0019] The boom adjustable throttle valve is communicated with the boom oil cylinder, the bucket adjustable throttle valve is communicated with the bucket oil cylinder, and the boom adjustable throttle valve is communicated with the boom oil cylinder.

[0020] Furthermore, the boom oil cylinder includes a boom lowering oil chamber and a boom raising oil chamber;

[0021] The arm oil cylinder includes an arm oil receiving chamber and an arm oil extending chamber;

[0022] The bucket oil cylinder includes a bucket oil collecting chamber and a bucket oil discharging chamber;

[0023] The boom pilot valve, the dipper rod pilot valve, and the bucket pilot valve are all double-control pilot valves, each having a first control port and a second control port disposed therein, the first control port and the second control port being connected to the control end of the reversing valve;

[0024] When the first control port of the boom pilot valve is pressurized, the boom oil lifting chamber becomes larger and the boom rises;

[0025] When the second control port of the boom pilot valve is pressurized, the boom lowering oil chamber becomes larger and the boom descends;

[0026] When the first control port of the boom pilot valve is pressurized, the boom extension oil chamber becomes larger and the boom extends;

[0027] When the second control port of the boom pilot valve is pressurized, the boom oil retraction chamber becomes larger and the boom is retracted;

[0028] When the first control port of the bucket pilot valve is pressurized, the bucket oil discharge chamber becomes larger and the bucket is released;

[0029] When the second control port of the bucket pilot valve is pressurized, the bucket oil receiving chamber becomes larger and the bucket is retracted.

[0030] Furthermore, the boom adjustable flow valve is connected to the boom extension oil chamber, and the hydraulic port of the boom bypass valve is connected to the second control port of the boom pilot valve, so as to speed up the boom retraction.

[0031] Or the boom adjustable flow valve is connected to the boom oil receiving chamber, and the hydraulic port of the boom bypass valve is connected to the first control port of the boom pilot valve to speed up the extension of the boom.

[0032] Further, the bucket adjustable flow valve is connected to the bucket oil discharge chamber, and the hydraulic port of the bucket bypass valve is connected to the second control port of the bucket pilot valve, so as to speed up the bucket retraction;

[0033] Or the bucket adjustable flow valve is connected to the bucket oil collection chamber, and the hydraulic port of the bucket bypass valve is connected to the first control port of the bucket pilot valve to speed up the bucket release.

[0034] Furthermore, the boom adjustable flow valve is connected to the boom lifting oil chamber, and the hydraulic port of the boom bypass valve is connected to the second control port of the boom pilot valve, so as to speed up the boom lowering speed;

[0035] Or the boom adjustable flow valve is connected to the boom lowering oil chamber, and the hydraulic port of the boom bypass valve is connected to the first control port of the boom pilot valve to speed up the boom raising speed.

[0036] In one embodiment of the utility model, two combined valves for lifting speed for an excavator as described in the first aspect are provided.

[0037] Compared with the prior art, the utility model has the following beneficial effects:

[0038] 1. After the combination valve involved in this patent is connected, during the operation of the hydraulic excavator, the boom is lowered, the arm recovery and bucket retraction actions are accelerated, which can increase the working speed of the excavator. After the combination valve is installed, the return oil resistance of the hydraulic oil is reduced. Due to the presence of the adjustable flow valve, the speed is controllable and the power consumption of the engine and hydraulic pump is not increased.

[0039] 2. The full process acceleration of the excavator can be achieved by setting two combination valves involved in this patent.

[0040] 3. The speed can be adjusted through the adjustable flow valve to adapt to low-speed working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of a combined valve for lifting speed of an excavator and an excavator according to the utility model;

[0042] Figure 2 This is a partial enlarged schematic diagram of the utility model Figure 1 ;

[0043] Figure 3 This is a partial enlarged schematic diagram of the utility model Figure 2 .

[0044] In the figure: 1. Boom; 2. Arm; 3. Bucket;

[0045] 4. Boom cylinder; 5. Arm cylinder; 6. Bucket cylinder;

[0046] 7. Arm reversing valve; 8. Bucket reversing valve; 9. Boom reversing valve;

[0047] 10. Stick pilot valve; 11. Bucket pilot valve; 12. Boom pilot valve;

[0048] 13. Adjustable flow valve for arm; 14. Adjustable flow valve for bucket; 15. Adjustable flow valve for boom;

[0049] 16. Arm bypass valve; 17. Bucket bypass valve; 18. Boom bypass valve;

[0050] LCs 1, arm check valve; LCs2, bucket check valve; LCs3, boom check valve;

[0051] A1, boom raising oil chamber; B1, boom lowering oil chamber; A2, arm collecting oil chamber; B2, arm extending oil chamber; A3, bucket collecting oil chamber; B3, bucket draining oil chamber;

[0052] XAa, right control end of the boom reversing valve; XAb, right control end of the boom reversing valve; XAk, right control end of the bucket reversing valve;

[0053] XCa, hydraulic port of the arm bypass valve; XCb, hydraulic port of the bucket bypass valve; XCc, hydraulic port of the boom bypass valve. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0055] Embodiment 1:

[0056] See also Figure 1The utility model provides a combined valve for lifting speed of an excavator, including a boom bypass valve 16, a bucket bypass valve 17, and a boom bypass valve 18. The boom bypass valve 16, the bucket bypass valve 17, and the boom bypass valve 18 have the same structure and are all hydraulic two-position two-way valves, including a closed position, an open position, a hydraulic port, a first port, and a second port. The hydraulic two-position two-way valve is normally in a closed position. The two ports of the boom bypass valve 16, the bucket bypass valve 17, and the boom bypass valve 18 are all connected to the oil tank T. One port of the boom bypass valve 16 is connected to an adjustable boom flow valve 13, one port of the bucket bypass valve 17 is connected to an adjustable bucket flow valve 14, and one port of the boom bypass valve 18 is connected to an adjustable boom flow valve 15. The throttle valve is used to control the flow rate of the hydraulic oil when the bypass valve is turned on.

[0057] Embodiment 2:

[0058] See also Figure 1 The utility model provides an excavator, including a platform, a boom 1, a dipper arm 2, a bucket 3, a boom cylinder 4, a dipper arm cylinder 5, and a bucket cylinder 6. The boom 1 is hinged to the platform, the boom cylinder 4 is respectively connected to the boom 1 and the platform, the dipper arm 2 is hinged to the boom 1, the dipper arm cylinder 5 is respectively connected to the dipper arm 2 and the boom 1, the bucket 3 is hinged to the dipper arm 2, and the bucket cylinder 6 is respectively connected to the bucket 3 and the dipper arm 2.

[0059] The specific structures of the platform, boom 1, arm 2, bucket 3, boom cylinder 4, arm cylinder 5, and bucket cylinder 6, and the forms of the connections are all prior art and are clear to those skilled in the art.

[0060] The boom cylinder 4 includes a boom lowering oil chamber B1 and a boom raising oil chamber A1. When the boom lowering oil chamber B1 becomes larger, the boom 1 descends, and when the boom raising oil chamber A1 becomes larger, the boom 1 rises.

[0061] Among them, the boom cylinder 5 includes a boom oil receiving chamber A2 and a boom extending chamber B2. When the boom oil receiving chamber A2 becomes larger, the boom 2 is retracted, and when the boom extending chamber B2 becomes larger, the boom 2 is extended.

[0062] The bucket cylinder 6 includes a bucket oil receiving chamber A3 and a bucket oil releasing chamber B3. When the bucket oil receiving chamber A3 becomes larger, the bucket 3 is retracted, and when the bucket oil releasing chamber B3 becomes larger, the bucket 3 is released.

[0063] An excavator further includes a boom reversing valve 7 , a boom pilot valve 10 , a bucket reversing valve 8 , a bucket pilot valve 11 , a boom reversing valve 9 , and a boom pilot valve 12 .

[0064] The arm reversing valve 7, bucket reversing valve 8 and boom reversing valve 9 have the same structure, and are all hydraulic three-position eight-way reversing valves including left position, middle position, right position, left position control end, right position control end, pump port, oil chamber one port, oil chamber two port and oil tank port; when the hydraulic three-position eight-way reversing valve is in the middle position, the pump port, oil chamber one port, oil chamber two port and oil tank port are all disconnected; when the hydraulic three-position eight-way reversing valve is in the right position, the pump port is connected to the oil chamber one port, and the oil chamber two port is connected to the oil tank port; when the hydraulic three-position eight-way reversing valve is in the left position, the pump port is connected to the oil chamber two port, and the oil chamber one port is connected to the oil tank port, and the remaining ports are used for other hydraulic equipment.

[0065] The arm pilot valve 10, the bucket pilot valve 11 and the boom pilot valve 12 are all double-control pilot valves, including a first control port and a second control port. The double-control pilot valve itself is an existing device, and includes a fuel tank pipeline and a pressure pipeline inside. Under normal circumstances, the first control port and the second control port are connected to the fuel tank pipeline without pressure. The first control port or the second control port is connected to the pressure pipeline through button electronic control and other means to output pressure.

[0066] The pump port of the boom reversing valve 7 is connected to the hydraulic pump through the boom check valve LCs 1, the oil chamber port 1 of the boom reversing valve 7 is connected to the boom oil receiving chamber A2, the oil chamber port 2 of the boom reversing valve 7 is connected to the boom oil extending chamber B2, and the oil tank port of the boom reversing valve 7 is connected to the oil tank T; the left control end XBa of the boom reversing valve is connected to the first control port of the boom pilot valve 10, and the right control end XAa of the boom reversing valve is connected to the second control port of the boom pilot valve 10.

[0067] The pump port of the bucket reversing valve 8 is connected to the hydraulic pump through the bucket check valve LCs2, the oil chamber port 1 of the bucket reversing valve 8 is connected to the bucket oil receiving chamber A3, the oil chamber port 2 of the bucket reversing valve 8 is connected to the bucket oil drain chamber B3, and the oil tank port of the bucket reversing valve 8 is connected to the oil tank T; the left control end XBk of the bucket reversing valve is connected to the first control port of the bucket pilot valve 11, and the right control end XAk of ​​the bucket reversing valve is connected to the second control port of the bucket pilot valve 11.

[0068] The pump port of the boom reversing valve 9 is connected to the hydraulic pump through the boom check valve LCs3, the oil chamber port 1 of the boom reversing valve 9 is connected to the boom lowering oil chamber B1, the oil chamber port 2 of the boom reversing valve 9 is connected to the boom raising oil chamber A1, and the oil tank port of the boom reversing valve 9 is connected to the oil tank T; the left control end XBb of the boom reversing valve is connected to the first control port of the boom pilot valve 12, and the right control end XAb of the boom reversing valve is connected to the second control port of the boom pilot valve 12.

[0069] The arm check valve LCs1, bucket check valve LCs2 and boom check valve LCs3 are used to protect the hydraulic pump.

[0070] An excavator also includes a combination valve for lifting speed of an excavator in Example 1, wherein the boom adjustable flow valve 13 is connected to the boom oil extension chamber B2, and the hydraulic port XCa of the boom bypass valve is connected to the second control port of the boom pilot valve 10; the bucket adjustable flow valve 14 is connected to the bucket oil discharge chamber B3; the hydraulic port XCb of the bucket bypass valve is connected to the second control port of the bucket pilot valve 11; the boom adjustable flow valve 15 is connected to the boom oil lifting chamber A1; the hydraulic port XCc of the boom bypass valve is connected to the second control port of the boom pilot valve 12.

[0071] The connection mode of the combined valve for lifting speed of an excavator provided in this embodiment can speed up the speed of retracting the dipper arm 2, retracting the bucket 3, and lowering the boom 1.

[0072] The specific workflow is:

[0073] When the boom pilot valve 10 moves to the left to execute the action of retracting the boom 2, the right position control end XAa of the boom reversing valve obtains the pressure oil P from the second control port of the boom pilot valve 10, and the right position of the boom reversing valve 7 works. The pressure oil P passes through the boom check valve LCs 1 and then enters the boom retracting oil chamber A2 of the boom cylinder 5 through the right position of the boom reversing valve 7. At the same time, the hydraulic oil in the boom extension oil chamber B2 of the boom cylinder 5 enters the oil pipe, and a part of it flows back to the oil tank T through the right position of the boom reversing valve 7.

[0074] At the same time, when the boom pilot valve 10 performs the action of retracting the boom 2, the pilot oil of the second control port of the boom pilot valve 10 simultaneously reaches the hydraulic port XCa of the boom bypass valve, and the through position of the boom bypass valve 16 is turned on, so that part of the hydraulic oil coming out of the boom extension oil chamber B2 of the boom cylinder 5 can flow back to the oil tank T through the boom adjustable flow valve 13 of the combination valve and the through position of the boom bypass valve 16; because the hydraulic oil in the boom extension oil chamber B2 of the boom cylinder 5 can return to the oil tank T through the combination valve, the oil return resistance is reduced and the speed of retracting the boom 2 is accelerated.

[0075] When the bucket pilot valve 11 moves to the left to perform the action of retracting the bucket 3, the right position control end XAk of ​​the bucket reversing valve obtains the pressure oil P from the second control port of the bucket pilot valve 11, and the right position of the bucket reversing valve 8 works. The pressure oil P passes through the bucket check valve LCs2 and then enters the bucket oil retracting chamber A3 of the bucket cylinder 6 through the right position of the bucket reversing valve 8. At the same time, the hydraulic oil in the bucket oil discharge chamber B3 of the bucket cylinder 6 enters the oil pipe, and a part of it flows back to the oil tank T through the right position of the bucket reversing valve 8;

[0076] At the same time, when the bucket pilot valve 11 retracts the bucket 3, the pilot oil of the second control port of the bucket pilot valve 11 simultaneously reaches the hydraulic port XCb of the bucket bypass valve, and the through position of the bucket bypass valve 17 is turned on, so that part of the hydraulic oil coming out of the bucket oil discharge chamber B3 of the bucket cylinder 6 can flow back to the oil tank T through the bucket adjustable flow valve 14 of the combination valve and the through position of the bucket bypass valve 17; because the hydraulic oil in the bucket oil discharge chamber B3 of the bucket cylinder 6 can return to the oil tank T through the combination valve, the oil return resistance is reduced and the speed of retracting the bucket 3 is accelerated.

[0077] When the boom pilot valve 12 moves to the left to perform the action of retracting the boom 1, the right position control end XAb of the boom reversing valve obtains the pressure oil P from the second control port of the boom pilot valve 12, and the right position of the boom reversing valve 9 works. The pressure oil P passes through the boom check valve LCs3 and then enters the boom lowering oil chamber B1 of the boom cylinder 4 through the right position of the boom reversing valve 9. At the same time, the hydraulic oil in the boom raising oil chamber A1 of the boom cylinder 4 enters the oil pipe, and a part of it flows back to the oil tank T through the right position of the boom reversing valve 9.

[0078] At the same time, when the boom pilot valve 12 performs the action of retracting the boom 1, the pilot oil of the second control port of the boom pilot valve 12 simultaneously reaches the hydraulic port XCc of the boom bypass valve, and the through position of the boom bypass valve 18 is turned on, so that part of the hydraulic oil coming out of the boom lifting chamber A1 of the boom cylinder 4 can flow back to the oil tank T through the boom adjustable flow valve 15 of the combination valve and the through position of the boom bypass valve 18; because the hydraulic oil in the boom lifting chamber A1 of the boom cylinder 4 can return to the oil tank T through the combination valve, the oil return resistance is reduced and the speed of the boom 1 descending is accelerated.

[0079] After connecting the combination valve involved in this patent, during the operation of the hydraulic excavator, the boom is lowered, the dipper arm recovery and bucket retraction actions are accelerated, which can increase the working speed of the excavator. After installing the combination valve, the return oil resistance of the hydraulic oil is reduced. Due to the presence of the adjustable flow valve, its speed is controllable and the power consumption of the engine and hydraulic pump is not increased.

[0080] Embodiment 3:

[0081] On the basis of Example 2, the boom adjustable throttle valve 13 is connected to the boom oil receiving chamber A2 , and the hydraulic port XCa of the boom bypass valve is connected to the first control port of the boom pilot valve 10 .

[0082] The bucket adjustable throttle valve 14 is communicated with the bucket oil receiving chamber A3 ; the hydraulic port XCb of the bucket bypass valve is communicated with the first control port of the bucket pilot valve 11 .

[0083] The boom adjustable flow valve 15 is communicated with the boom oil lowering chamber B1 ; the hydraulic port XCc of the boom bypass valve is communicated with the first control port of the boom pilot valve 12 .

[0084] The connection mode of the combined valve for lifting speed of an excavator provided in this embodiment can speed up the extension of the dipper arm 2, the lowering of the bucket 3, and the raising of the boom 1.

[0085] Embodiment 4:

[0086] Based on Example 2, this embodiment provides two combination valves. Without changing the original wiring of Example 2, the adjustable flow valve of the boom of the second combination valve is connected to the boom oil receiving chamber A2, and the hydraulic port XCa of the boom bypass valve of the second combination valve is connected to the first control port of the boom pilot valve 10.

[0087] The bucket adjustable flow valve of the second combination valve is connected to the bucket oil receiving chamber A3; the hydraulic port XCb of the bucket bypass valve of the second combination valve is connected to the first control port of the bucket pilot valve 11; the boom adjustable flow valve of the second combination valve is connected to the boom oil lowering chamber B1.

[0088] The hydraulic port XCc of the boom bypass valve of the second combination valve is communicated with the first control port of the boom pilot valve 12 .

[0089] The connection method of the combined valve for lifting speed of an excavator provided in this embodiment can speed up the speed of retracting the dipper arm 2, retracting the bucket 3, and lowering the boom 1, and can also speed up the speed of extending the dipper arm 2, lowering the bucket 3, and raising the boom 1, and the speed is adjustable.

[0090] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0091] In the present invention, the term "plurality" means two or more than two, unless otherwise clearly defined. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0092] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0093] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0094] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A combination valve for lifting speed of an excavator, characterized in that: Including arm bypass valve, bucket bypass valve, boom bypass valve; The arm bypass valve, bucket bypass valve and boom bypass valve have the same structure and include a closed position, an open position, a hydraulic port, a single port and a double port, and the normal state is the closed position; The two ports of the arm bypass valve, the bucket bypass valve and the boom bypass valve are all connected to the oil tank; One port of the boom bypass valve is connected to a boom adjustable flow valve; One port of the bucket bypass valve is connected to a bucket adjustable flow valve; One port of the boom bypass valve is connected with a boom adjustable flow valve.

2. An excavator comprising a platform, a boom, a dipper arm and a bucket which are articulated in sequence; It also includes a boom cylinder, a dipper rod cylinder, and a bucket cylinder; the boom cylinder is connected to the boom and the platform respectively, the dipper rod cylinder is connected to the dipper rod and the boom respectively, and the bucket cylinder is connected to the bucket and the dipper rod respectively; It also includes a boom reversing valve, a bucket reversing valve, and a boom reversing valve; the boom reversing valve is connected to the boom cylinder, the bucket reversing valve is connected to the bucket cylinder, and the boom reversing valve is connected to the boom cylinder; It also includes a boom pilot valve, a bucket pilot valve, and a boom pilot valve; the boom pilot valve is connected to the control end of the boom reversing valve, the bucket pilot valve is connected to the control end of the bucket reversing valve, and the boom pilot valve is connected to the control end of the boom reversing valve; It is characterized in that It also includes a combined valve for lifting speed for an excavator as claimed in claim 1; The hydraulic port of the arm bypass valve is communicated with the arm pilot valve, the hydraulic port of the bucket bypass valve is communicated with the bucket pilot valve, and the hydraulic port of the boom bypass valve is communicated with the boom pilot valve; The boom adjustable throttle valve is communicated with the boom oil cylinder, the bucket adjustable throttle valve is communicated with the bucket oil cylinder, and the boom adjustable throttle valve is communicated with the boom oil cylinder.

3. An excavator according to claim 2, characterized in that: The boom oil cylinder includes a boom lowering oil chamber and a boom raising oil chamber; The arm oil cylinder includes an arm oil retracting chamber and an arm oil extending chamber; The bucket oil cylinder includes a bucket oil collecting chamber and a bucket oil discharging chamber; The boom pilot valve, the dipper rod pilot valve, and the bucket pilot valve are all double-control pilot valves, each having a first control port and a second control port disposed therein, the first control port and the second control port being connected to the control end of the reversing valve; When the first control port of the boom pilot valve is pressurized, the boom oil lifting chamber becomes larger and the boom rises; When the second control port of the boom pilot valve is pressurized, the boom lowering oil chamber becomes larger and the boom descends; When the first control port of the boom pilot valve is pressurized, the boom extension oil chamber becomes larger and the boom extends; When the second control port of the boom pilot valve is pressurized, the boom oil retraction chamber becomes larger and the boom is retracted; When the first control port of the bucket pilot valve is pressurized, the bucket oil discharge chamber becomes larger and the bucket is released; When the second control port of the bucket pilot valve is pressurized, the bucket oil receiving chamber becomes larger and the bucket is retracted.

4. An excavator according to claim 3, characterized in that: The boom adjustable flow valve is connected to the boom extension oil chamber, and the hydraulic port of the boom bypass valve is connected to the second control port of the boom pilot valve to speed up the boom retraction. Or the boom adjustable flow valve is connected to the boom oil receiving chamber, and the hydraulic port of the boom bypass valve is connected to the first control port of the boom pilot valve to speed up the extension of the boom.

5. An excavator according to claim 3, characterized in that: The bucket adjustable flow valve is connected to the bucket oil discharge chamber, and the hydraulic port of the bucket bypass valve is connected to the second control port of the bucket pilot valve to speed up the bucket retraction; Or the bucket adjustable flow valve is connected to the bucket oil collection chamber, and the hydraulic port of the bucket bypass valve is connected to the first control port of the bucket pilot valve to speed up the bucket release.

6. An excavator according to claim 3, characterized in that: The adjustable flow valve of the boom is connected to the boom oil raising chamber, and the hydraulic port of the boom bypass valve is connected to the second control port of the boom pilot valve to speed up the boom lowering speed; Or the boom adjustable flow valve is connected to the boom lowering oil chamber, and the hydraulic port of the boom bypass valve is connected to the first control port of the boom pilot valve to speed up the boom raising speed.

7. An excavator according to any one of claims 2 to 6, characterized in that: Two combined valves for lifting speed of an excavator as described in claim 1 are provided.

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