Working accessory flow limiting and adjusting hydraulic system and excavator

Abstract

The utility model belongs to the technical field of excavators, and discloses a working accessory flow limiting and adjusting hydraulic system and an excavator, the hydraulic system comprises a main pump and a main valve, and the main valve comprises a standby linkage reversing valve used for controlling a working accessory; the pilot control oil way comprises a pilot control valve, a first pilot oil way and a second pilot oil way, the first pilot oil way and the second pilot oil way are separated from the pilot control valve, the first pilot oil way is used for controlling reversing of the standby linkage reversing valve, and the second pilot oil way is a negative feedback control oil way used for controlling the maximum pumping displacement of the main pump. According to the working accessory flow limiting and adjusting hydraulic system, by changing the control mode of the pilot oil way, one pilot oil way is branched from the pilot control oil way where the pilot control valve is located to control the maximum displacement of the main pump, so that flow limiting and adjusting of the working accessory are achieved, and the working accessory flow limiting and adjusting hydraulic system is simple, practical and high in practicability. And the power control and other actions of the main pump are not influenced.

Description

Technical Field

[0001] The present application belongs to the technical field of excavators, and in particular, relates to a flow limiting and regulating hydraulic system for working accessories and an excavator. Background Art

[0002] The working tools of the excavator include various types of breakers. Breakers of different specifications are used for different working environments. Breakers of different specifications and types require different hydraulic oil flows. The existing excavators generally use large-flow, low-frequency hydraulic hammers. The pilot control method of the hydraulic hammer pipeline is shown in Figure 1 , by manipulating the pilot valve, the pilot pump provides pilot control oil for the pilot valve, and this pilot oil controls the switching of the standby reversing valve of the main valve, and then provides pressure oil to the hydraulic hammer pipeline. This pilot control pipeline is simple and effective, but it is only suitable for ordinary large flow and low frequency hydraulic hammers; when using a high-frequency silent breaker, excessive flow can be achieved by reducing power, but after reducing the pump speed, although the flow requirements of the high-frequency silent breaker are met, the action speed of the breaker will be greatly affected. Summary of the invention

[0003] The purpose of the present application is to provide a hydraulic system and an excavator for limiting and regulating flow of working accessories, so as to be suitable for the use flow and flow control requirements of more types of working accessories.

[0004] To achieve the above-mentioned object, the present application provides a first aspect of a working tool flow limiting and regulating hydraulic system, comprising a main pump and a main valve, wherein the main valve comprises a backup joint reversing valve for controlling the working tool; and

[0005] The pilot control oil circuit includes a pilot control valve and a first pilot oil circuit and a second pilot oil circuit branched from the pilot control valve, wherein the first pilot oil circuit is used to control the switching of the standby joint reversing valve, and the second pilot oil circuit is a negative feedback control oil circuit used to control the maximum pumping displacement of the main pump.

[0006] In some embodiments, a pressure regulating valve is provided in the second pilot oil circuit, and the pressure regulating valve is used to adjust the maximum oil circuit pressure of the second pilot oil circuit.

[0007] In some embodiments, the pressure regulating valve comprises an adjustable relief valve or an adjustable pressure reducing valve.

[0008] In some embodiments, a throttle valve is provided at the upstream end of the pressure regulating valve.

[0009] In some embodiments, the pilot control valve is a pilot foot valve, and the working tool flow limiting and regulating hydraulic system further includes a pilot pump for supplying oil to the pilot foot valve.

[0010] In some embodiments, the main pump includes a first pump and a second pump, the pumping oil port of the first pump and the pumping oil port of the second pump merge and are hydraulically connected to the oil inlet of the backup joint reversing valve, the pumping oil port of the first pump is also connected to a first pressure relief oil circuit, and the pumping oil port of the second pump is also connected to a second pressure relief oil circuit; the main valve also includes a first merging control valve arranged in the first pressure relief oil circuit and a second merging control valve arranged in the second pressure relief oil circuit.

[0011] In some embodiments, the second pilot oil circuit includes:

[0012] a first shuttle valve, one comparison oil port of the first shuttle valve being hydraulically connected to the oil outlet port of the first confluence control valve, the other comparison oil port of the first shuttle valve being hydraulically connected to the pilot control valve, and the comparison oil outlet port of the first shuttle valve being connected to the negative feedback oil port of the first pump; and

[0013] a second shuttle valve, wherein one comparison oil port of the second shuttle valve is hydraulically connected to the oil outlet port of the second confluence control valve, the other comparison oil port is hydraulically connected to the pilot control valve, and the comparison oil outlet port of the second shuttle valve is connected to the negative feedback oil port of the second pump.

[0014] In some embodiments, the first merging control valve and the second merging control valve are both hydraulically controlled reversing valves pilot-connected to the first pilot oil circuit.

[0015] A second aspect of the present application provides an excavator, which includes a working attachment flow limiting and regulating hydraulic system according to the present application.

[0016] In some embodiments, the working attachment of the excavator includes a high-frequency silent breaker.

[0017] In the hydraulic system for flow limitation and regulation of working accessories according to the present application, when a working accessory with a small flow requirement is replaced, in order to achieve flow limitation and regulation of the working accessory, a pilot oil circuit is branched out from the pilot control oil circuit where the pilot control valve is located, namely, the second pilot oil circuit, to control the maximum displacement of the main pump, thereby meeting the flow regulation and control of the working accessories with a small flow requirement. Compared with the method of reducing the power of the main pump in the prior art to achieve flow limitation and regulation by changing the pilot oil circuit control method, the present application does not affect the power control and other actions of the main pump, nor does it affect the movement speed of the entire machine.

[0018] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative work. In the accompanying drawings:

[0020] Figure 1 It is a pilot control principle diagram of a hydraulic hammer pipeline in an excavator in the prior art;

[0021] Figure 2 A pipeline connection diagram of a flow limiting and regulating hydraulic system for working accessories according to a specific embodiment of the present application; and

[0022] Figure 3 It is a hydraulic principle diagram of a flow limiting and regulating hydraulic system for working accessories according to a specific embodiment of the present application.

[0023] Description of Reference Numerals

[0024] 1 First pump 2 Second pump

[0025] 3 Pilot pump 4 First shuttle valve

[0026] 5 Second shuttle valve 6 Pilot control valve

[0027] 7 Throttle valve 8 Pressure regulating valve

[0028] 9 Spare reversing valve 10 Main valve

[0029] 11 First confluence control valve 12 Second confluence control valve

[0030] L1 First pilot oil circuit L2 Second pilot oil circuit DETAILED DESCRIPTION

[0031] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0032] A working attachment flow limiting and regulating hydraulic system and an excavator according to the present application will be described below with reference to the accompanying drawings.

[0033] In order to adapt to the different flow and control requirements of more types of working tools, this application specifically develops a new type of working tool flow limiting and regulating hydraulic system. Figure 2 , Figure 3 As shown, in a specific embodiment, the flow limiting and regulating hydraulic system of the working attachment includes:

[0034] A main pump and a main valve 10, wherein the main valve 10 includes a spare joint reversing valve 9 for controlling working accessories;

[0035] The pilot control oil circuit includes a pilot control valve 6 and a first pilot oil circuit L1 and a second pilot oil circuit L2 branching from the pilot control valve 6. The first pilot oil circuit L1 is used to control the switching of the standby joint reversing valve 9, and the second pilot oil circuit L2 is a negative feedback control oil circuit used to control the maximum pumping displacement of the main pump.

[0036] The present application aims to control the working accessories (such as a breaker) without changing the habitual operation logic, and to adjust the pipeline flow of the working accessories by changing the pilot oil circuit to meet the different flow requirements of the working accessories, such as Figure 2 As shown. Taking the breaker hammer of an excavator as an example, in the prior art, when a high-frequency silent breaker hammer is used, the hydraulic oil flow is too high and the vibration is large. At this time, although the small flow requirement of the hydraulic hammer can be met by reducing the power and speed, the movement speed of the whole machine will be greatly affected. To this end, the present application uses the negative flow control characteristic, that is, the greater the negative feedback pressure, the smaller the main pump flow control characteristic, and borrows the crushing pilot pressure to control the maximum displacement of the main pump by adjusting the pressure, so as to achieve the flow control purpose of the breaker hammer pipeline without affecting the power control and other actions of the main pump.

[0037] Specifically, see Figure 2 , Figure 3 By changing the pilot oil circuit control mode, that is, branching off a pilot oil circuit (i.e., the second pilot oil circuit L2) from the hydraulic hammer pilot oil circuit led out from the pilot pump 3, the maximum displacement of the main pump is controlled to meet the flow rate required by the hydraulic hammer.

[0038] In this embodiment, a pressure regulating valve 8 may also be provided in the second pilot oil circuit L2, and the pressure regulating valve 8 is used to adjust the maximum oil circuit pressure of the second pilot oil circuit L2. That is, according to the pumping displacement characteristics of different main pumps, the pilot pressure of the second pilot oil circuit L2 is adjusted accordingly by the pressure regulating valve 8 to match the main pump.

[0039] It is understood by those skilled in the art that there are various types of hydraulic valves used for pressure regulation in hydraulic pipelines, such as Figure 3 The pressure regulating valve 8 used in the embodiment is an adjustable relief valve, and the hydraulic oil exceeding the set relief pressure will overflow to the hydraulic oil tank. Thus, the maximum pilot pressure in the second pilot oil circuit L2 which is diverted can be set. Figure 3 The adjustable relief valve can be manual or electronically controlled. Of course, the pressure regulating valve 8 can also be other types of valves, such as an adjustable pressure reducing valve.

[0040] Furthermore, a throttle valve 7 is also provided at the upstream end of the pressure regulating valve 8 of this embodiment, that is, a small-aperture throttle valve is added at the oil inlet of the overflow valve, which achieves the purpose of hydraulic hammer flow adjustment without affecting the power control and other actions of the main pump.

[0041] This embodiment takes an excavator as an example, and its pilot control valve 6 is generally a pilot foot valve, and the hydraulic system also includes a pilot pump 3 for supplying oil to the pilot foot valve. The pilot pump 3 works continuously, thereby continuously providing pilot pressure oil to the first pilot oil circuit L1 and the second pilot oil circuit L2, and the oil of the second pilot oil circuit L2 that is diverted does not affect the pilot oil supply of the first pilot oil circuit L1.

[0042] The main pump supplies hydraulic oil to the main valve 10, etc., and can be a single pump or a double pump. The main pump of this embodiment includes a first pump 1 and a second pump 2. Figure 3 As shown, the oil delivery port of the first pump 1 and the oil delivery port of the second pump 2 merge and are hydraulically connected to the oil inlet of the standby joint reversing valve 9; the oil delivery port of the first pump 1 is also connected to the first pressure relief oil circuit, and the oil delivery port of the second pump 2 is also connected to the second pressure relief oil circuit; the main valve 10 also includes a first merging control valve 11 arranged in the first pressure relief oil circuit and a second merging control valve 12 arranged in the second pressure relief oil circuit.

[0043] When the confluence control valve is in the disconnected state, all the pressure oil pumped out of the pumping port will be directed to the standby joint reversing valve 9, etc., while when the confluence control valve is in the on state, the pumping pressure oil of the pumping port can be returned to the hydraulic oil tank through the pressure relief oil circuit. The post-valve hydraulic oil of the confluence control valve can be fed back to the negative feedback oil port of the main pump to adjust the corresponding main pump displacement according to the confluence state. In this embodiment, the first confluence control valve 11 and the second confluence control valve 12 are both hydraulically controlled reversing valves pilot-connected to the first pilot oil circuit L1.

[0044] On this basis, the second pilot oil circuit L2 may also include:

[0045] a first shuttle valve 4, one comparison oil port of the first shuttle valve 4 is hydraulically connected to the oil outlet of the first confluence control valve 11, the other comparison oil port is hydraulically connected to the pilot control valve 6, and the comparison oil outlet of the first shuttle valve 4 is connected to the negative feedback oil port of the first pump 1; and

[0046] The second shuttle valve 5 , one comparison oil port of the second shuttle valve 5 is hydraulically connected to the oil outlet of the second confluence control valve 12 , the other comparison oil port is hydraulically connected to the pilot control valve 6 , and the comparison oil outlet of the second shuttle valve 5 is connected to the negative feedback oil port of the second pump 2 .

[0047] On the basis that the hydraulic oil behind the valve of the merging control valve can be fed back to the negative feedback oil port of the main pump, in order to avoid oil cross-talk between the pilot control oil of the second merging control valve 12 and the pilot oil behind the valve of the merging control valve, a first shuttle valve 4 and a second shuttle valve 5 are respectively provided in the present embodiment to feed back the larger of the two pilot oils to the negative feedback oil port of the main pump without causing oil cross-talk.

[0048] For specific control operations, see Figure 2 , Figure 3 The operator can operate the pilot control valve 6 by foot, and the pilot pump 3 provides pilot control oil for the pilot control valve 6. The pilot control oil is divided into two routes: one is the first pilot oil route L1, which controls the backup reversing valve 9 of the main valve 10 and the XBp1 link of the main valve; the other is the second pilot oil route L2, which supplies oil to the pressure regulating valve 8; the outlet pilot pressure is adjusted through the pressure regulating valve 8. Due to the reversing action of the standby reversing valve 9 and the XBp1 reversing valve, the output hydraulic oil of the first pump 1 and the second pump 2 cannot pass through the N1 port and the N2 port to the first shuttle valve 4 and the second shuttle valve 5, or the pressure is very small and cannot play a role in adjusting the pump displacement; at the same time, the oil pressure from the pressure regulating valve 8 is greater than the oil pressure from the N1 port and the N2 port, so the pressure oil at the outlet P2 of the pressure regulating valve 8 controls the negative feedback oil ports Pi1 and Pi2 of the first pump 1 and the second pump 2 respectively through the three-way shuttle valve (the first shuttle valve 4 and the second shuttle valve 5), thereby changing the displacement of the two pumps, reducing the hydraulic oil flow output from the main pump to the breaker, and effectively avoiding excessive system flow.

[0049] The purpose of adjusting the oil supply of the hydraulic hammer can be achieved by adjusting the set value of the pressure regulating valve 8. A throttle valve 7 is installed at the front oil inlet of the pressure regulating valve 8. For example, the throttle size is 0.8 mm, which can ensure that the pilot oil at the oil port of the overflow valve does not affect the pilot oil circuit pressure of the whole machine.

[0050] On the basis of the above working attachment flow limiting and regulating hydraulic system, the present application accordingly provides an excavator, which includes the working attachment flow limiting and regulating hydraulic system of the present application. The above is explained using an excavator as an example, but the working attachment flow limiting and regulating hydraulic system of the present application is not limited to an excavator. Similarly, the above-mentioned working attachments include a high-frequency silent breaker, and the working attachment flow limiting and regulating hydraulic system of the present application is particularly suitable for use in excavators with high-frequency silent breaker. Of course, working attachments are not limited to breakers, but may also include common pile drivers, hydraulic shears, crushing pliers, hawkbill shears, car dismantling shears, wood / stone lotus grabs, crushing buckets, tree movers, vibratory rammers, etc. The flow control of each working attachment can be achieved through the working attachment flow limiting and regulating hydraulic system of the present application.

[0051] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0052] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A hydraulic system for limiting and regulating the flow of working attachments, characterized in that: The working attachment flow limiting and regulating hydraulic system comprises: A main pump and a main valve (10), wherein the main valve (10) includes a backup joint reversing valve (9) for controlling a working tool; and The pilot control oil circuit comprises a pilot control valve (6) and a first pilot oil circuit (L1) and a second pilot oil circuit (L2) branched from the pilot control valve (6), wherein the first pilot oil circuit (L1) is used to control the switching of the standby joint reversing valve (9), and the second pilot oil circuit (L2) is a negative feedback control oil circuit used to control the maximum pumping displacement of the main pump.

2. The hydraulic system for limiting and regulating flow of working tools according to claim 1, characterized in that: A pressure regulating valve (8) is provided in the second pilot oil circuit (L2), and the pressure regulating valve (8) is used to adjust the maximum oil circuit pressure of the second pilot oil circuit (L2).

3. The hydraulic system for limiting and regulating flow of working tools according to claim 2, characterized in that: The pressure regulating valve (8) comprises an adjustable overflow valve or an adjustable pressure reducing valve.

4. The hydraulic system for limiting and regulating flow of working tools according to claim 2, characterized in that: A throttle valve (7) is provided at the upstream end of the pressure regulating valve (8).

5. The hydraulic system for limiting and regulating flow of working tools according to claim 1, characterized in that: The pilot control valve (6) is a pilot foot valve, and the working tool flow limiting and regulating hydraulic system further comprises a pilot pump (3) for supplying oil to the pilot foot valve.

6. The hydraulic system for limiting and regulating flow of working tools according to any one of claims 1 to 5, characterized in that: The main pump comprises a first pump (1) and a second pump (2); the oil delivery port of the first pump (1) and the oil delivery port of the second pump (2) merge and are hydraulically connected to the oil inlet of the standby joint reversing valve (9); the oil delivery port of the first pump (1) is also connected to a first pressure relief oil circuit, and the oil delivery port of the second pump (2) is also connected to a second pressure relief oil circuit; the main valve (10) further comprises a first merging control valve (11) arranged in the first pressure relief oil circuit and a second merging control valve (12) arranged in the second pressure relief oil circuit.

7. The hydraulic system for limiting and regulating flow of working tools according to claim 6, characterized in that: The second pilot oil circuit (L2) comprises: a first shuttle valve (4), wherein one comparison oil port of the first shuttle valve (4) is hydraulically connected to the oil outlet port of the first merging control valve (11), the other comparison oil port is hydraulically connected to the pilot control valve (6), and the comparison oil outlet port of the first shuttle valve (4) is connected to the negative feedback oil port of the first pump (1); and A second shuttle valve (5), one comparison oil port of the second shuttle valve (5) is hydraulically connected to the oil outlet port of the second confluence control valve (12), the other comparison oil port is hydraulically connected to the pilot control valve (6), and the comparison oil outlet port of the second shuttle valve (5) is connected to the negative feedback oil port of the second pump (2).

8. The hydraulic system for limiting and regulating flow of working tools according to claim 6, characterized in that: The first merging control valve (11) and the second merging control valve (12) are both hydraulically controlled directional control valves pilot-connected to the first pilot oil circuit (L1).

9. An excavator, characterized in that The excavator comprises the working attachment flow limiting and regulating hydraulic system according to any one of claims 1 to 8.

10. The excavator according to claim 9, characterized in that: The working tool is a high-frequency silent breaker.

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