CN217759051U

CN217759051U - Fixed-variable hydraulic system of loader

Info

Publication number: CN217759051U
Application number: CN202221887435.9U
Authority: CN
Inventors: 张军帅; 李磊; 马良
Original assignee: Shanxi Nuohao New Energy Technology Co ltd
Current assignee: Shanxi Nuohao New Energy Technology Co ltd
Priority date: 2022-07-22
Filing date: 2022-07-22
Publication date: 2022-11-08
Anticipated expiration: 2032-07-22

Abstract

The utility model provides a loader fixed variable hydraulic system belongs to loader technical field. The loader constant-variable hydraulic system comprises a constant-variable gear pump, a variable plunger pump, a confluence control valve, a working valve, a steering valve, an unloading valve, a shuttle valve, a steering oil cylinder, a bucket oil cylinder and a movable arm oil cylinder. The quantitative gear pump, the unloading valve, the confluence control valve and the working valve are communicated in sequence, the bucket oil cylinder and the movable arm oil cylinder are communicated with the confluence control valve through the working valve, the variable plunger pump is communicated with the steering valve, the steering valve is connected with the steering oil cylinder, and a steering priority valve is arranged in the steering valve. When the loader does not act, the energy loss is small, the energy consumption is reduced, the operation comfort is good, and the output flow of the variable plunger pump and the quantitative gear pump after passing through the flow combination control valve is completely matched with the load flow requirement.

Description

Fixed-variable hydraulic system of loader

Technical Field

The utility model relates to a loader technical field particularly, relates to a loader fixed variable hydraulic system.

Background

The loader is a common earth-shoveling transportation machine and is widely used in places such as earth-rock operation, loose material operation, mine operation and the like, main working devices are a movable arm and a bucket, the movable arm is generally lifted through a hydraulic oil cylinder, the bucket is overturned through a connecting rod mechanism connected with the hydraulic oil cylinder, and steering action is executed through the hydraulic oil cylinder and a front frame and rear frame hinged device.

At present, constant delivery pumps are commonly adopted by loaders on the market to respectively supply oil to a working device oil cylinder and a steering oil cylinder, the output oil displacement cannot be adjusted, the actual flow is adjusted through the input rotating speed of the pumps, and when no action requirement exists on the working device and the steering, the unloading is carried out through an unloading valve and a working valve middle position, the system standby pressure is high, the loss is large, and the system heating value and the energy consumption are high. In addition, the steering oil cylinder is driven by oil discharged by a steering gear, the steering operation force is large, the operation comfort is poor, and when the steering action demand is small, the throttle pressure loss is large and the system energy consumption is further increased due to the fact that the output flow of a steering pump is constant.

How to invent a loader fixed variable hydraulic system to improve the problems becomes a problem to be solved urgently by the technical personnel in the field.

SUMMERY OF THE UTILITY MODEL

In order to compensate above not enough, the utility model provides a loader fixed variable hydraulic system energy loss is little when the loader does not have the action, reduces the energy consumption, and it is good to manipulate the travelling comfort, makes the output flow behind variable plunger pump and the ration gear pump coincidence flow control valve, matches completely in the load flow demand.

The utility model discloses a realize like this:

the quantitative gear pump, the unloading valve, the confluence control valve and the working valve are sequentially communicated, the bucket oil cylinder and the movable arm oil cylinder are communicated through the working valve, the confluence control valve is communicated with the variable plunger pump, the variable plunger pump is communicated with the steering valve, the steering valve is connected with the steering oil cylinder, a steering priority valve is arranged in the steering valve, the steering priority valve is communicated with the confluence control valve, a logic valve is arranged in the confluence control valve and communicated with the working valve, the shuttle valve collects the pressure of the steering valve and the confluence control valve and feeds the pressure back to a displacement control unit of the variable plunger pump, and the unloading valve is installed on the quantitative gear pump.

In a specific embodiment, the steering cylinders are mechanically connected to the front and rear frames respectively by pins.

In a specific embodiment, the position of the oil path of the working valve communicated with the boom cylinder is a 4-position valve core.

The beneficial effect of this application is: 1. when the loader does not act, the displacement of the variable plunger pump is minimum, the constant delivery pump returns oil at low pressure, and the energy loss is extremely small; 2. the steering system is supplied with oil by a variable plunger pump, and the output flow of the variable plunger pump depends on the load; 3. the steering operation and the working device operation are pilot hydraulic control, and the operation comfort is good; 4. the steering priority function is realized, the variable plunger pump preferentially supplies oil to a steering system, the safety of the loader is ensured, and the residual oil is converged with the quantitative gear pump according to the load of a working device, so that the energy consumption is reduced while the working efficiency is improved; 5. the discharge capacity of the variable plunger pump is controlled by a shuttle valve signal, pressure signals of a working circuit and a steering circuit are taken, and the output flow of the variable plunger pump and the output flow of the quantitative gear pump after passing through the flow combination control valve are completely matched with the load flow demand through logic judgment; 6. especially under the working condition of small flow, compared with a quantitative system, the energy consumption is obviously reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic diagram of a fixed-variable hydraulic system of a loader according to an embodiment of the present invention.

In the figure: 1-a quantitative gear pump; 2-variable plunger pump; 3-a confluence control valve; 4-a working valve; 5-a diverter valve; 6-an unloading valve; 7-a shuttle valve; 8-a steering oil cylinder; 9-a bucket cylinder; 10-a boom cylinder.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention are combined to clearly and completely describe the technical solutions of the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Examples

Referring to fig. 1, the utility model provides a loader constant variable hydraulic system, including quantitative gear pump 1, variable plunger pump 2, confluence control valve 3, service valve 4, steering valve 5, unload valve 6, shuttle valve 7, steering cylinder 8, scraper bowl hydro-cylinder 9 and movable arm hydro-cylinder 10, quantitative gear pump 1, unload valve 6, confluence control valve 3 and service valve 4 communicate in order, scraper bowl hydro-cylinder 9 and movable arm hydro-cylinder 10 communicate in confluence control valve 3 through service valve 4. The quantitative gear pump 1, the unloading valve 6, the confluence control valve 3 and the working valve 4 are connected in sequence, and oil is supplied to the bucket cylinder 9 and the movable arm cylinder 10 under the control of the working valve 4. The variable displacement plunger pump 2 is communicated with a steering valve 5, and the steering valve 5 is connected with a steering oil cylinder 8. Specifically, the steering cylinder 8 is supplied with oil by the control of the steering valve 5. A steering priority valve is arranged in the steering valve 5, the steering priority valve is communicated with the confluence control valve 3, a logic valve is arranged in the confluence control valve 3, and the logic valve is communicated with the working valve 4. The remaining hydraulic fluid in the steering valve 5 is output to the confluence control valve 3 through the steering priority valve, and is supplied to the working valve 4 at an appropriate timing according to the pressure setting of the logic valve in the confluence control valve 3, so as to be merged with the hydraulic fluid supplied from the fixed-displacement gear pump 1. The shuttle valve 7 collects the pressures of the steering valve 5 and the confluence control valve 3 and feeds them back to the displacement control unit of the variable displacement plunger pump 2. In specific setting, the shuttle valve 7 takes the pressures of the working circuit and the steering circuit and feeds back a signal to the displacement control unit of the variable displacement plunger pump 2, thereby controlling the displacement of the variable displacement plunger pump 2. The unloading valve 6 is installed on the quantitative gear pump 1. In the present embodiment, the unloading valve 6 is installed on the fixed-displacement gear pump 1 to protect the fixed-displacement gear pump 1 and to set the maximum pressure of the main working circuit.

In this embodiment, the steering cylinders 8 are mechanically connected to the front and rear frames, respectively, by pins. Wherein, the steering oil cylinder 8 is two pieces, the rod cavity and the rodless cavity are connected in a cross way through a pipeline, and the steering of the loader is realized through extending and retracting the oil cylinder. The steering valve 5 and the working valve 4 are each controlled by external pilot oil. The quantitative gear pump 1 supplies oil to the working valve 4 to drive the bucket cylinder 9 and the movable arm cylinder 10, the variable displacement plunger pump 2 supplies oil to the steering cylinder 8, redundant oil is supplied to the working valve 4 through the confluence control valve 3, the working speed of the bucket cylinder 9 and the working speed of the movable arm cylinder 10 are improved, and the working valve 4 and the steering valve 5 are respectively driven through a working handle and a steering gear in a pilot mode, so that the operating force is reduced, and the comfort is improved. The variable displacement piston pump 2 preferentially supplies oil to the steering valve 5, the displacement of the variable displacement piston pump is controlled by actual steering pressure and working pressure in real time, and the amount of the oil output in real time is determined according to the load. The position of the working valve 4 communicated with the oil path of the movable arm oil cylinder 10 is a 4-position valve core. The communication between the rod chamber and the rodless chamber of the boom cylinder 10 is realized by the magnitude of the pilot pressure, so that the boom floating function is realized.

Specifically, the working principle of the loader constant-variable hydraulic system is as follows: when the loader does not have any action, the oil output by the quantitative gear pump 1 directly returns to the oil tank through the middle position of the working valve 4, and the variable displacement plunger pump 2 is at the set minimum displacement because of no load feedback signal, and basically has no pressure loss at the moment. When the loader performs steering action, the steering valve 5 is driven by pilot oil, and the variable plunger pump 2 adjusts the output flow according to the pressure of a steering main loop and provides the flow for the steering valve 5, so that the steering oil cylinder 8 is driven, and proper steering flow is provided according to actual requirements. When the steering and the working devices of the loader are simultaneously operated, if the load of the working device is increased, the steering valve 5 supplies redundant oil to the confluence control valve 3, and the confluence control valve 3 merges the redundant oil of the steering system and the oil of the fixed-displacement gear pump 1 through logic control and simultaneously supplies the redundant oil to the working valve 4, thereby improving the efficiency of the working device. When the load of the working device of the loader is small, the confluence control valve 3 closes the confluence oil path through logic control, and at the moment, the working device only supplies oil through the quantitative gear pump 1, so that the energy consumption is reduced. The actual displacement of the variable displacement plunger pump 2 is controlled by the steering load and the working load, the shuttle valve 7 selects a larger value of the steering load and the working load, and signals are fed back to the control unit of the variable displacement plunger pump 2, so that the required displacement is provided according to the actual requirement, and the energy waste is avoided. The steering valve 5 has a priority function, preferentially provides oil output by the variable plunger pump 2 to a steering loop, and transmits the residual flow when the steering system works to the confluence control valve through a priority valve core according to the preset value of the logic valve.

It should be noted that the specific model specifications of the quantitative gear pump 1, the variable plunger pump 2, the confluence control valve 3, the working valve 4, the steering valve 5, the unloading valve 6, the shuttle valve 7, the steering cylinder 8, the bucket cylinder 9 and the boom cylinder 10 need to be determined by model selection according to the actual specification of the device, and the specific model selection calculation method adopts the prior art in the field, so detailed description is omitted.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The constant-variable hydraulic system of the loader is characterized by comprising a quantitative gear pump (1), a variable plunger pump (2), a confluence control valve (3), a working valve (4), a steering valve (5), an unloading valve (6), a shuttle valve (7), a steering oil cylinder (8), a bucket oil cylinder (9) and a movable arm oil cylinder (10), wherein the quantitative gear pump (1), the unloading valve (6), the confluence control valve (3) and the working valve (4) are sequentially communicated, the bucket oil cylinder (9) and the movable arm oil cylinder (10) are communicated with the confluence control valve (3) through the working valve (4), the variable plunger pump (2) is communicated with the steering valve (5), the steering valve (5) is connected with the steering oil cylinder (8), a steering priority valve is arranged in the steering valve (5), the steering priority valve is communicated with the confluence control valve (3), a logic valve is arranged in the confluence control valve (3), the logic valve is communicated with the working valve (4), the shuttle valve (7) collects pressure of the diversion valve (5) and the confluence control valve (3), and feeds back the pressure of the confluence control valve (6) to a quantitative gear pump (1) and a displacement control unit (1).

2. The constant-variable hydraulic system of the loader as claimed in claim 1, wherein the steering cylinders (8) are mechanically connected to the front and rear frames respectively by pins.

3. The constant-variable hydraulic system of the loader as claimed in claim 1 wherein the position of the working valve (4) where the oil path to the boom cylinder (10) is connected is a 4-position spool.