Hydraulic driving system for movable arm of excavator

Abstract

The invention relates to a hydraulic driving system for a movable arm of an excavator, which belongs to the hydraulic technical field of excavators and comprises a base, a large arm and a small arm which are sequentially hinged, and further comprises a main hydraulic cylinder and an auxiliary hydraulic cylinder, one end of the main hydraulic cylinder is hinged above the large arm, the main hydraulic cylinder is provided with a first hydraulic cylinder and a third hydraulic cylinder, and the other end of the first hydraulic cylinder is hinged to the base; the other end of the third hydraulic cylinder is hinged above the small arm; one end of the auxiliary hydraulic cylinder is hinged to the lower portion of the large arm, the auxiliary hydraulic cylinder is provided with a second hydraulic cylinder and a fourth hydraulic cylinder, the other end of the second hydraulic cylinder is hinged to the base, and the other end of the fourth hydraulic cylinder is hinged to the lower portion of the small arm; the technical problems that in the prior art, due to single-side hydraulic cylinder driving, when a hydraulic system leaks, a hydraulic cylinder loses pressure, a movable arm falls due to the dead weight, and safety is low can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic pressure of excavators, and in particular relates to a hydraulic driving system of an excavator boom. Background Art

[0002] The excavator boom is an extremely important component of the excavator. With the help of the telescopic action of the hydraulic cylinder connected to it, the boom can control a variety of actions. Therefore, the efficiency and safety of the hydraulic drive system are particularly important for the excavator boom.

[0003] The existing patent with application number CN202410197420.7 discloses a hydraulic excavator energy-saving system. The hydraulic excavator energy-saving system also includes an anti-settling valve. The anti-settling valve is arranged at the large cavity outlet of the boom cylinder and is respectively connected to the flow extraction valve and the main valve boom connection. When the hydraulic excavator is in a non-boom lowering condition, the main valve boom is in a neutral position and the anti-settling valve is locked. At this time, the boom is locked to prevent the boom from falling due to its own weight.

[0004] The prior art has the following problems:

[0005] The boom and forearm of existing excavator booms are mostly driven by single-sided hydraulic cylinders. Even if the anti-settling valve is locked, when the hydraulic system leaks due to other reasons, the hydraulic cylinder will still lose pressure and cause the boom to fall due to its own weight, which has low safety. Summary of the invention

[0006] The invention provides a hydraulic drive system for an excavator boom, which can solve the technical problem of low safety in the prior art in which a single-side hydraulic cylinder drive causes the boom to fall due to its own weight when the hydraulic system leaks, resulting in a loss of pressure in the hydraulic cylinder.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0008] The present application provides a hydraulic drive system for an excavator boom, comprising a base, an upper arm and a lower arm articulated in sequence, and further comprising a main hydraulic cylinder and an auxiliary hydraulic cylinder, wherein one end of the main hydraulic cylinder is hinged to the top of the upper arm, and the main hydraulic cylinder has a first hydraulic cylinder and a third hydraulic cylinder, the other end of the first hydraulic cylinder is hinged to the base, and the other end of the third hydraulic cylinder is hinged to the top of the lower arm; one end of the auxiliary hydraulic cylinder is hinged to the bottom of the upper arm, and the auxiliary hydraulic cylinder has a second hydraulic cylinder and a fourth hydraulic cylinder, the other end of the second hydraulic cylinder is hinged to the base, and the other end of the fourth hydraulic cylinder is hinged to the bottom of the lower arm.

[0009] Through the above technical solution, the main hydraulic cylinder and auxiliary hydraulic cylinder are arranged up and down, which can prevent the boom from falling due to its own weight when a single cylinder leaks, thereby improving the safety of the excavator boom.

[0010] In the present invention, the above-mentioned main liquid cylinder has a main retraction chamber and a main extension chamber, and the auxiliary liquid cylinder has an auxiliary retraction chamber and an auxiliary extension chamber. A driven liquid circuit is connected between the main retraction chamber and the auxiliary retraction chamber, and a driving liquid circuit is connected between the main extension chamber and the auxiliary extension chamber. The driving liquid circuit is connected to a variable pump and a reversing valve.

[0011] Through the above technical solution, the hydraulic circuits of the main hydraulic cylinder and the auxiliary hydraulic cylinder are interconnected. When the boom moves in the opposite direction, the hydraulic oil discharged from one of the hydraulic cylinders can be used as the driving force for the other hydraulic cylinder, thereby avoiding energy loss caused by energy conversion through accumulators, etc., and improving the energy utilization efficiency when the boom is switching.

[0012] In the present invention, the above-mentioned excavator boom hydraulic drive system also includes a first safety valve and a second safety valve. The first safety valve is connected to the auxiliary fluid cylinder, and the first safety valve controls the auxiliary fluid cylinder to connect or disconnect the fluid circuit based on the pressure of the driven fluid circuit; the second safety valve is connected to the main fluid cylinder, and the second safety valve controls the main fluid cylinder to connect or disconnect the fluid circuit based on the pressure in the pipeline between the reversing valve and the auxiliary fluid cylinder.

[0013] Through the above technical solution, the first safety valve and the second safety valve are used. When leakage and pressure loss occur in the driven hydraulic circuit or the driving hydraulic circuit, the main hydraulic cylinder or the auxiliary hydraulic cylinder can be disconnected and the pressure can be maintained, thereby maintaining the posture of the boom, avoiding continued use after the hydraulic system leaks and causing safety accidents.

[0014] In the present invention, the hydraulic drive system of the excavator boom further includes a buffer tube, a plurality of buffer tubes are connected to the driven fluid circuit and the driving fluid circuit, and the buffer tube expands according to the pressure increase of the driven fluid circuit or the driving fluid circuit.

[0015] Through the above technical solution, the buffer tube is used to absorb the instantaneous potential energy generated in the reverse direction of the liquid path, thereby causing elastic deformation, and then the elastic potential energy is converted into the potential energy of the hydraulic oil when the deformation is restored, thereby reducing the friction between the hydraulic oil and the tube wall when the direction is changed, thereby reducing the energy loss caused by heat.

[0016] In the present invention, the inner wall of the buffer tube is coated with a PTFE coating.

[0017] Through the above technical solution, the use of PTFE coating further reduces the friction between the buffer tube and the hydraulic oil, thereby improving the efficiency of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A structural isometric diagram of a hydraulic drive system for an excavator boom provided by an embodiment of the present invention;

[0020] Figure 2 A structural side view of a hydraulic drive system for an excavator boom provided by an embodiment of the present invention;

[0021] Figure 3 A hydraulic schematic diagram of a hydraulic drive system for an excavator boom provided in an embodiment of the present invention.

[0022] Icons: 1-base; 101-first hydraulic cylinder; 102-second hydraulic cylinder; 2-upper arm; 201-third hydraulic cylinder; 202-fourth hydraulic cylinder; 3-lower arm; 301-fifth hydraulic cylinder; 401-main hydraulic cylinder; 402-auxiliary hydraulic cylinder; 403-reversing valve; 404-variable pump; 405-first safety valve; 406-second safety valve; 407-first pressure relief valve; 408-fluid replenishing pump; 409-second pressure relief valve; 410-oil cylinder; 411-buffer pipe; 412-driven hydraulic circuit; 413-driving hydraulic circuit. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0024] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] 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 the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be welding, bolt connection, or riveting; it can be fixed connection, detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] Example:

[0028] Please refer to Figures 1 to 3 , Figures 1 to 3 An embodiment of the present application is shown.

[0029] This embodiment provides a hydraulic drive system for an excavator boom, such as Figure 1 As shown, it includes a base 1, a large arm 2 and a small arm 3 which are hinged in sequence. Figure 2 As shown, it also includes a main liquid cylinder 401 and an auxiliary liquid cylinder 402. One end of the main liquid cylinder 401 is hinged to the top of the upper arm 2, and the main liquid cylinder 401 has a first liquid cylinder 101 and a third liquid cylinder 201. The other end of the first liquid cylinder 101 is hinged to the base 1, and the other end of the third liquid cylinder 201 is hinged to the top of the forearm 3; one end of the auxiliary liquid cylinder 402 is hinged to the bottom of the upper arm 2, and the auxiliary liquid cylinder 402 has a second liquid cylinder 102 and a fourth liquid cylinder 202. The other end of the second liquid cylinder 102 is hinged to the base 1, and the other end of the fourth liquid cylinder 202 is hinged to the bottom of the forearm 3.

[0030] When in use, the base 1 is connected to the excavator body, and then the main hydraulic cylinder 401 is extended and the auxiliary hydraulic cylinder 402 is retracted to achieve the lowering and recovery of the boom.

[0031] Different from the layout of setting driving cylinders on both sides which can only provide stronger driving force, the main cylinder 401 and the auxiliary cylinder 402 are respectively set on the upper and lower sides of the boom, which can still provide a more balanced support effect after a single-side cylinder leaks, thereby avoiding tilting.

[0032] Through the above technical solution, the main hydraulic cylinder 401 and the auxiliary hydraulic cylinder 402 are arranged up and down, which can prevent the boom from falling due to its own weight when a single oil cylinder 410 leaks, thereby improving the safety of the excavator boom.

[0033] As a preferred implementation method, Figure 3As shown, the above-mentioned main liquid cylinder 401 has a main retraction chamber and a main extension chamber, the auxiliary liquid cylinder 402 has an auxiliary retraction chamber and an auxiliary extension chamber, the main retraction chamber and the auxiliary retraction chamber are connected by a driven liquid circuit 412, the main extension chamber and the auxiliary extension chamber are connected by a driving liquid circuit 413, and the driving liquid circuit 413 is connected to a variable pump 404 and a reversing valve 403.

[0034] like Figure 3 As shown, when in use, the variable pump 404 pumps the hydraulic oil in the main extension chamber of the main hydraulic cylinder 401 into the auxiliary extension chamber of the auxiliary hydraulic cylinder 402, thereby completing the retraction of the main hydraulic cylinder 401 and the extension of the auxiliary hydraulic cylinder 402, thereby allowing the boom to rise upward, and the push rod is used to drive the reversing valve 403 for operation when changing direction.

[0035] It should be noted that if Figure 3 The figure shows a hydraulic diagram of a group of cylinders, such as the first cylinder 101 and the second cylinder 102 are a group, the third cylinder 201 and the fourth cylinder 202 are a group, and the two groups of hydraulic pressure are independently controlled. Figure 2 As shown, the bucket is only independently connected to the fifth cylinder 301, and does not use Figure 3 Hydraulic diagram shown.

[0036] Through the above technical solution, the hydraulic circuits of the main hydraulic cylinder 401 and the auxiliary hydraulic cylinder 402 are interconnected. When the boom moves in the opposite direction, the hydraulic oil discharged from one of the hydraulic cylinders can be used as the driving force for the other hydraulic cylinder, thereby avoiding energy loss caused by energy conversion through accumulators, etc., and improving the energy utilization efficiency when the boom is switching.

[0037] As a preferred implementation method, Figure 3 As shown, the above-mentioned excavator boom hydraulic drive system also includes a first safety valve 405 and a second safety valve 406. The first safety valve 405 is connected to the auxiliary fluid cylinder 402, and the first safety valve 405 controls the auxiliary fluid cylinder 402 to connect or disconnect the fluid circuit based on the pressure of the driven fluid circuit 412; the second safety valve 406 is connected to the main fluid cylinder 401, and the second safety valve 406 controls the main fluid cylinder 401 to connect or disconnect the fluid circuit based on the pressure in the pipeline between the reversing valve 403 and the auxiliary fluid cylinder 402.

[0038] When in use, two sets of safety valves are used to control the on-off of the fluid circuit according to the pressure in the driving fluid circuit 413 and the driven fluid circuit 412. When a certain section of the fluid circuit leaks and the hydraulic pressure is reduced, the safety valve pipe wall disconnects the main fluid cylinder 401 or the auxiliary fluid cylinder 402. The disconnected fluid cylinder can retain the hydraulic oil inside and obtain stable hydraulic support.

[0039] It should be noted that if Figure 3As shown, in order to avoid the loss of hydraulic oil when the variable pump 404 is working, a fluid replenishment pump 408 is also connected to the driving fluid circuit 413, and the fluid replenishment pump 408 is connected to the fluid circuit through a one-way valve, and a second pressure relief valve 409 is also connected to the front end of the fluid replenishment pump 408 to prevent excessive pressure during fluid replenishment. The output end of the variable pump 404 is connected to the first pressure relief valve 407, and the first pressure relief valve 407, the fluid replenishment pump 408 and the second pressure relief valve 409 are all connected to the oil cylinder 410.

[0040] Through the above technical solution, the first safety valve 405 and the second safety valve 406 are used. When leakage and pressure loss occur in the driven hydraulic circuit 412 or the driving hydraulic circuit 413, the main hydraulic cylinder 401 or the auxiliary hydraulic cylinder 402 can be disconnected to maintain pressure, thereby maintaining the posture of the boom, avoiding continued use after the hydraulic system leaks and causing safety accidents.

[0041] As a preferred embodiment, the above-mentioned excavator boom hydraulic drive system also includes a buffer tube 411, and multiple buffer tubes 411 are connected to the driven fluid circuit 412 and the driving fluid circuit 413. The buffer tube 411 expands according to the increase in pressure of the driven fluid circuit 412 or the driving fluid circuit 413.

[0042] During use, when the pressurized hydraulic oil suddenly flows in the reverse direction in the pipeline, the buffer tube 411 will expand under the action of the impact force to absorb part of the energy brought by the reverse flow, so that the flow state of the hydraulic oil changes relatively smoothly. At the same time, because the diameter of the buffer tube 411 increases after expansion, according to the principles of fluid mechanics, when the local diameter of the pipeline increases, under the condition of unchanged flow rate (assuming that the overall flow rate can be approximately regarded as unchanged in a short time when the hydraulic oil flows in the reverse direction), the flow rate of the hydraulic oil will decrease, and the reduced flow rate will reduce the friction coefficient between the hydraulic oil and the pipe wall, thereby reducing the friction resistance. When the flow state is stable, the buffer tube 411 contracts and converts the elastic potential energy into the flow potential energy of the hydraulic oil.

[0043] Through the above technical solution, the buffer tube 411 is used to absorb the instantaneous potential energy generated in the reverse direction of the liquid path, thereby causing elastic deformation, and then converting the elastic potential energy into the potential energy of the hydraulic oil when restoring the deformation, thereby reducing the friction between the hydraulic oil and the tube wall when switching direction, thereby reducing the energy loss caused by heat.

[0044] As a preferred implementation, the inner wall of the buffer tube 411 is coated with a PTFE coating.

[0045] PTFE (polytetrafluoroethylene) has an extremely low friction coefficient, usually between 0.04-0.15. It is an excellent self-lubricating material. It can form a smooth lubricating film on the surface to reduce friction when in contact with other objects. At the same time, PTFE has good chemical stability, acid and alkali resistance, organic solvent resistance and other corrosion resistance, and can maintain its performance in a variety of harsh environments. It also has certain heat resistance and cold resistance, and is suitable for a wide temperature range.

[0046] When in use, a PTFE coating is applied to the inner surface of the buffer tube 411 by spraying or dipping, which can not only maintain the elasticity of the buffer tube 411 itself, but also give it a self-lubricating effect, effectively reducing the friction between it and other components during use, thereby improving its service life and work efficiency.

[0047] Through the above technical solution, the PTFE coating is used to further reduce the friction between the buffer tube 411 and the hydraulic oil, thereby improving the efficiency of the hydraulic system.

[0048] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A hydraulic drive system for an excavator boom, comprising a base (1), a boom (2) and a forearm (3) which are articulated in sequence, characterized in that: Also includes: A main liquid cylinder (401), one end of which is hinged to the upper part of the upper arm (2), the main liquid cylinder (401) comprising a first liquid cylinder (101) and a third liquid cylinder (201), the other end of the first liquid cylinder (101) being hinged to the base (1), and the other end of the third liquid cylinder (201) being hinged to the upper part of the lower arm (3); An auxiliary liquid cylinder (402) has one end hinged to the bottom of the upper arm (2), and the auxiliary liquid cylinder (402) has a second liquid cylinder (102) and a fourth liquid cylinder (202), the other end of the second liquid cylinder (102) is hinged to the base (1), and the other end of the fourth liquid cylinder (202) is hinged to the bottom of the lower arm (3).

2. The hydraulic drive system for an excavator boom according to claim 1, characterized in that: The main liquid cylinder (401) has a main retraction chamber and a main extension chamber, the auxiliary liquid cylinder (402) has an auxiliary retraction chamber and an auxiliary extension chamber, a driven liquid circuit (412) is connected between the main retraction chamber and the auxiliary retraction chamber, a driving liquid circuit (413) is connected between the main extension chamber and the auxiliary extension chamber, and the driving liquid circuit (413) is connected to a variable pump (404) and a reversing valve (403).

3. The hydraulic drive system for an excavator boom according to claim 2, characterized in that: Also includes: A first safety valve (405) connected to the auxiliary liquid cylinder (402), the first safety valve (405) controlling the auxiliary liquid cylinder (402) to connect or disconnect the liquid circuit based on the pressure of the driven liquid circuit (412); The second safety valve (406) is connected to the main liquid cylinder (401), and the second safety valve (406) controls the main liquid cylinder (401) to connect or disconnect the liquid circuit based on the pressure in the pipeline between the reversing valve (403) and the auxiliary liquid cylinder (402).

4. The hydraulic drive system for an excavator boom according to claim 3, characterized in that: Also includes: A plurality of buffer tubes (411) are connected to the driven fluid path (412) and the driving fluid path (413), and the buffer tubes (411) expand in response to an increase in pressure in the driven fluid path (412) or the driving fluid path (413).

5. The hydraulic drive system for an excavator boom according to claim 4, characterized in that: The inner wall of the buffer tube (411) is coated with a PTFE coating.

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