Double-variable hydraulic system of loading machine

Abstract

The utility model relates to the technical field of hydraulic control of loaders, and provides a double-variable hydraulic system of a loader, which comprises a hydraulic oil tank, a variable pump I, a variable pump II, a pilot valve I, a pilot valve II, a movable arm cylinder, a rotating bucket cylinder, a movable arm link, a composite action device and a rotating bucket link, the movable arm link is connected with the movable arm cylinder and the composite action device; the pilot valve II is connected with a rotating bucket coupler; the rotating bucket coupler is connected with a rotating bucket cylinder and a composite action device; the input ends of the first variable pump and the second variable pump are connected with an oil inlet of the hydraulic oil tank, and the output ends of the first variable pump and the second variable pump are connected with the movable arm set and the rotating bucket set respectively. According to the double-variable hydraulic system, the pressure loss during composite action of the movable arm and the rotating bucket in the existing double-variable hydraulic system can be eliminated, and more energy is saved; meanwhile, local system heating is reduced, the oil oxidation phenomenon is reduced, and the system failure rate is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of loader hydraulic control, in particular to a loader dual variable hydraulic system. Background Art

[0002] In the dual-variable hydraulic system of the loader, when the boom and the bucket work at the same time (compound action), the load pressures of the boom and the bucket are not equal. If there is no load compensation function, the boom and the bucket can only work first with the smaller load. Therefore, in the current multi-way valve, the bucket link and the boom link are each equipped with a pressure compensator, and the oil circuit with the smaller load is raised to the same pressure as the higher load by the pressure compensator, so that the two links can work simultaneously.

[0003] In actual use, the oil circuit with light load is raised to the same pressure as the high load by the pressure compensator so that the two links can work simultaneously. When the load pressures differ greatly, the difference between the two is consumed in the pressure compensator with the lower pressure, which will cause greater energy loss and local heating, accelerate the oxidation of the hydraulic oil, reduce the service life of the hydraulic oil, increase the system failure rate and accelerate the wear of hydraulic components.

[0004] Therefore, in view of the above problems, a loader dual variable hydraulic system is proposed to solve the above problems. Utility Model Content

[0005] The utility model aims at the deficiencies of the prior art and develops a dual-variable hydraulic system for a loader. The utility model can eliminate the pressure loss during the combined action of the boom and the bucket in the existing dual-variable hydraulic system, and is more energy-efficient; at the same time, it can reduce the heating of the local system, reduce the oxidation of the oil, and reduce the system failure rate.

[0006] The technical solution of the utility model to solve the technical problem is as follows: the utility model provides a dual variable hydraulic system for a loader, including a hydraulic oil tank, a variable pump 1, a variable pump 2, a pilot valve 1, a pilot valve 2, a boom cylinder, a bucket cylinder, a boom linkage, a compound action device and a bucket linkage;

[0007] The pilot valve 1 is connected to the boom coupling, which is connected to the boom cylinder and the compound action device; the pilot valve 2 is connected to the bucket coupling, which is connected to the bucket cylinder and the compound action device;

[0008] The input ends of the variable pump 1 and the variable pump 2 are connected to the oil outlet of the hydraulic oil tank, and the output ends of the variable pump 1 and the variable pump 2 are respectively connected to the boom connection and the bucket connection; the pilot valve 1, the pilot valve 2, the boom connection, the compound action device and the bucket connection are all connected to the oil return port of the hydraulic oil tank.

[0009] As an optimization, the compound action device includes a compound action valve, a reversing valve one, a reversing valve two, a shuttle valve one and a shuttle valve two. The reversing valve one is connected to the pilot valve one through the shuttle valve one, the reversing valve two is connected to the pilot valve two through the shuttle valve two, and the reversing valve one and the reversing valve two are respectively connected to the left end and the right end of the compound action valve.

[0010] As an optimization, it also includes a pressure oil source block, the input end of the pressure oil source block is connected to the output end of the variable pump one, the output end of the pressure oil source block is connected to pilot valve one, pilot valve two, reversing valve one and reversing valve two, and the pressure oil source block is also connected to the oil return port of the hydraulic oil tank.

[0011] As an optimization, a steering device is also included, and an output end of the variable pump is connected to the boom coupling through the steering device.

[0012] As an optimization, the steering device is also connected to the oil return port of the hydraulic oil tank.

[0013] The effects provided in the utility model content are only the effects of the embodiments, not all the effects of the utility model. The above technical solution has the following advantages or beneficial effects:

[0014] By setting up a compound action device and utilizing the compound action device, the pressure loss during the compound action of the boom and bucket in the existing dual variable hydraulic system can be eliminated, which is more energy-efficient; at the same time, the heating of the local system can be reduced, the oxidation of the oil can be reduced, and the system failure rate can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention.

[0016] Figure 1 It is the hydraulic principle diagram of the utility model;

[0017] Figure 2 For this utility model Figure 1 The enlarged view of point A in the middle;

[0018] Figure 3 For this utility model Figure 1 The enlarged view of point B in the middle;

[0019] Figure 4 For this utility model Figure 1 Enlarged view of point C in the middle.

[0020] In the figure, 1, hydraulic oil tank; 2, variable pump 1; 3, variable pump 2; 4, pilot valve 1; 5, pilot valve 2; 6, boom cylinder; 7, bucket cylinder; 8, boom coupling; 9, compound action device; 10, bucket coupling; 11, compound action valve; 12, reversing valve 1; 13, reversing valve 2; 14, shuttle valve 1; 15, shuttle valve 2; 16, pressure oil source block; 17, steering device. DETAILED DESCRIPTION

[0021] In order to clearly illustrate the technical features of this solution, the utility model is described in detail below through specific implementation methods and in combination with the accompanying drawings. The disclosure below provides many different embodiments or examples for realizing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. In addition, the utility model can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. It should be noted that the components illustrated in the accompanying drawings are not necessarily drawn to scale. The utility model omits the description of known components and processing technologies and processes to avoid unnecessary limitations on the utility model. The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0022] like Figures 1 to 4 As shown, a dual variable hydraulic system for a loader includes a hydraulic oil tank 1, a variable pump 1 2, a variable pump 2 3, a pilot valve 1 4, a pilot valve 2 5, a boom cylinder 6, a bucket cylinder 7, a boom link 8, a compound action device 9 and a bucket link 10;

[0023] The pilot valve 1 4 is connected to the boom link 8, which is connected to the boom cylinder 6 and the compound action device 9; the pilot valve 2 5 is connected to the bucket link 10, which is connected to the bucket cylinder 7 and the compound action device 9;

[0024] The input ends of variable pump 1 2 and variable pump 2 3 are connected to the oil outlet of hydraulic oil tank 1, and the output ends of variable pump 1 2 and variable pump 2 3 are respectively connected to the boom link 8 and the bucket link 10; pilot valve 1 4, pilot valve 2 5, boom link 8, compound action device 9 and bucket link 10 are all connected to the oil return port of hydraulic oil tank 1.

[0025] By providing the compound action device 9 and utilizing the compound action device 9, the pressure loss during the compound action of the boom and the bucket in the existing dual variable hydraulic system can be eliminated, thereby saving more energy; at the same time, the heating of the local system can be reduced, the oxidation of the oil can be reduced, and the system failure rate can be reduced.

[0026] In this embodiment, the compound action device 9 includes a compound action valve 11, a reversing valve 12, a reversing valve 13, a shuttle valve 14 and a shuttle valve 15. The reversing valve 12 is connected to the pilot valve 4 through the shuttle valve 14, and the reversing valve 13 is connected to the pilot valve 2 5 through the shuttle valve 15. The reversing valve 12 and the reversing valve 13 are respectively connected to the left end and the right end of the compound action valve 11.

[0027] In this embodiment, it also includes a pressure oil source block 16, the input end of the pressure oil source block 16 is connected to the output end of the variable pump 2, the output end of the pressure oil source block 16 is connected to the pilot valve 1 4, the pilot valve 2 5, the reversing valve 1 12 and the reversing valve 2 13, and the pressure oil source block 16 is also connected to the oil return port of the hydraulic oil tank 1.

[0028] In this embodiment, a steering device 17 is also included, and the output end of the variable displacement pump 2 is connected to the boom linkage 8 through the steering device 17.

[0029] In this embodiment, the steering device 17 is also connected to the oil return port of the hydraulic oil tank 1.

[0030] Working process:

[0031] 1. The boom lift and bucket flip up move simultaneously:

[0032] The pressure oil from the port C1 of the pilot valve 14 enters the left end of the boom link 8. At this time, the boom link 8 is in the left position. At the same time, the pressure oil from the port C1 of the pilot valve 14 also enters the upper end of the reversing valve 12 through the shuttle valve 14. The reversing valve 12 is switched to the upper position. The pilot pressure oil from the pressure oil source block 16 enters the left end of the compound action valve 11 through the reversing valve 12.

[0033] The pressure oil from port C2 of pilot valve 25 enters the left end of the rotating bucket link 10. At this time, the rotating bucket link 10 is in the left position. At the same time, the pressure oil from port C2 of pilot valve 25 also enters the lower end of reversing valve 213 through shuttle valve 215. Reversing valve 213 is switched to the lower position. The pressure oil at the right end of compound action valve 11 returns to the oil return port of hydraulic oil tank 1 through reversing valve 213 to release pressure.

[0034] The compound action valve 11 overcomes the right end spring force under the action of the pilot pressure oil at its left end and switches to the left position, thereby cutting off the oil paths connecting it with the boom link 8 and the bucket link 10, Ls1 and Ls2, and the oil paths connecting P1 and P2, so that the oil from the variable pump 12 reaches the Pd port of the boom link 8 from the P1' port, the Pd port of the boom link 8 is connected with the B1 port, the hydraulic oil enters the large chamber of the boom cylinder 6, the boom is lifted, the small chamber of the boom cylinder 6 is connected with the A1 port of the boom link 8, and then fed back through Ls1 To variable pump 12, the oil from variable pump 2 is only supplied to the boom link 8; the oil from variable pump 23 reaches the Pz port of the bucket link 10 from the P2' port, the Pz port of the bucket link 10 is connected with the B2 port, the hydraulic oil enters the large chamber of the bucket cylinder 7, the bucket is flipped up, the small chamber of the bucket cylinder 7 is connected with the A2 port of the bucket link 10, and then fed back to the variable pump 23 through Ls2, the oil from variable pump 23 is only supplied to the bucket link 10, the actions of the boom link 8 and the bucket link 10 do not interfere with each other, thereby realizing a compound action.

[0035] 2. The boom lowers and the bucket flips up at the same time:

[0036] The pressure oil from the port d1 of the pilot valve 4 enters the right end of the boom link 8. At this time, the boom link 8 is in the second position on the right. At the same time, the pressure oil from the port d1 of the pilot valve 4 enters the upper end of the reversing valve 12 through the shuttle valve 14. The reversing valve 12 is in the upper position. The pilot pressure oil from the pressure oil source block 16 enters the left end of the compound action valve 11 through the reversing valve 12.

[0037] The pressure oil from the port d2 of the pilot valve 25 enters the left end of the bucket link 10. At this time, the bucket link is in the left position. At the same time, the pressure oil from the port d2 of the pilot valve 25 enters the lower end of the reversing valve 213 through the shuttle valve 215. The reversing valve 213 is in the lower position. The pressure oil at the right end of the compound action valve 11 returns to the oil return port of the hydraulic oil tank 1 through the reversing valve 213 to release the pressure.

[0038] The compound action valve 11 overcomes the right end spring force under the action of the pilot pressure oil at its left end and switches to the left position, thereby cutting off the oil paths connecting it with the boom link 8 and the bucket link 10, Ls1 and Ls2, and the oil paths connecting P1 and P2, so that the oil from the variable pump 12 reaches the Pd port of the boom link 8 from the P1' port, the Pd port of the boom link 8 is connected with the A1 port, the hydraulic oil enters the small chamber of the boom cylinder 6, the boom is lowered, the large chamber of the boom cylinder 6 is connected with the B1 port of the boom link 8, and then fed back through Ls1 To variable pump 2, the oil from variable pump 2 is only supplied to the boom link 8; the oil from variable pump 23 reaches the Pz port of the bucket link 10 from the P2' port, the Pz port of the bucket link 10 is connected with the B2 port, the hydraulic oil enters the large chamber of the bucket cylinder 7, to realize the bucket flipping, the small chamber of the bucket cylinder 7 is connected to the A2 port of the bucket link 10, and then fed back to the variable pump 23 through Ls2, the oil from variable pump 23 is only supplied to the bucket link 10, the actions of the boom link 8 and the bucket link 10 do not interfere with each other, thereby realizing a compound action.

[0039] 3. Composite work exit:

[0040] 3.1: Exit one of the compound action of excavation working condition

[0041] When the pilot valve 4 returns to the middle position, the pilot pressure at both ends of the boom link 8 is zero, the valve stem of the boom link 8 returns to the middle position, the output pressure of the shuttle valve 14 is also zero, and the reversing valve 12 returns to the lower position under the action of its spring, and the pressure oil at the left end of the compound action valve 11 returns to the return oil port of the hydraulic oil tank 1 through the reversing valve 12 to relieve the pressure; under the action of the return spring force at the right end of the compound action valve 11, the compound action valve 11 is in the right position, Ls1 and Ls2 are connected through the compound action valve 11, P1 and P2 are connected through the compound action valve 11, and the system returns to the double pump confluence state.

[0042] 3.2: Exit 2 of compound action of excavation condition

[0043] When the pilot valve 25 returns to the middle position, the pilot pressure at both ends of the rotating bucket link 10 is zero, the valve stem of the rotating bucket link 10 returns to the middle position, the output pressure of the shuttle valve 215 is also zero, and the reversing valve 213 returns to the upper position under the action of its spring.

[0044] The pilot pressure oil from the pressure oil source block 16 enters the right end of the compound action valve 11 through the reversing valve 13. The control pressures at the left and right ends of the compound action valve 11 are equal. Under the action of the right end return spring force, the compound action valve is in the right position, Ls1 and Ls2 are connected through the compound action valve 11, P1 and P2 are connected through the compound action valve 11, and the system also restores the dual pump confluence state.

[0045] Although the specific implementation methods of the utility model are described above in conjunction with the accompanying drawings, this does not limit the scope of protection of the utility model. On the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A dual variable hydraulic system for a loader, characterized by: It comprises a hydraulic oil tank (1), a variable pump 1 (2), a variable pump 2 (3), a pilot valve 1 (4), a pilot valve 2 (5), a boom cylinder (6), a bucket cylinder (7), a boom link (8), a compound action device (9) and a bucket link (10); The pilot valve 1 (4) is connected to the boom link (8), and the boom link (8) is connected to the boom cylinder (6) and the compound action device (9); the pilot valve 2 (5) is connected to the bucket link (10), and the bucket link (10) is connected to the bucket cylinder (7) and the compound action device (9); The input ends of the variable pump 1 (2) and the variable pump 2 (3) are connected to the oil outlet of the hydraulic oil tank (1), and the output ends of the variable pump 1 (2) and the variable pump 2 (3) are connected to the boom link (8) and the bucket link (10) respectively; the pilot valve 1 (4), the pilot valve 2 (5), the boom link (8), the compound action device (9) and the bucket link (10) are all connected to the oil return port of the hydraulic oil tank (1).

2. The dual variable hydraulic system for a loader according to claim 1, characterized in that: The compound action device (9) comprises a compound action valve (11), a first reversing valve (12), a second reversing valve (13), a first shuttle valve (14) and a second shuttle valve (15). The first reversing valve (12) is connected to the first pilot valve (4) via the first shuttle valve (14), the second reversing valve (13) is connected to the second pilot valve (5) via the second shuttle valve (15), and the first reversing valve (12) and the second reversing valve (13) are respectively connected to the left end and the right end of the compound action valve (11).

3. The loader dual variable hydraulic system according to claim 2, characterized in that: The pressure oil source block (16) is also included. The input end of the pressure oil source block (16) is connected to the output end of the variable pump (2). The output end of the pressure oil source block (16) is connected to the pilot valve (4), the pilot valve (5), the reversing valve (12) and the reversing valve (13). The pressure oil source block (16) is also connected to the oil return port of the hydraulic oil tank (1).

4. The dual variable hydraulic system for a loader according to claim 1, characterized in that: It also includes a steering device (17), and the output end of the variable displacement pump (2) is connected to the boom link (8) through the steering device (17).

5. The dual variable hydraulic system for a loader according to claim 4, characterized in that: The steering device (17) is also connected to the oil return port of the hydraulic oil tank (1).

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