CN103591060B - Engineering machinery and hydraulic control oil circuit thereof - Google Patents

Abstract

The invention discloses a construction machine and its hydraulic control oil circuit, wherein the hydraulic control oil circuit of the construction machine comprises: an engine, a first oil pump, a controller, the engine is connected to the first oil pump; the oil at the oil outlet of the first oil pump If the oil pressure is greater than the oil pressure at the oil inlet, the hydraulic control oil circuit of construction machinery also includes: a common rail device and a pressure sensor; the oil inlet of the common rail device is connected to the oil outlet of the first oil pump, and the oil outlet of the common rail device is connected to the work Oil cylinder; the pressure sensor is used to sense the oil pressure information in the rail of the common rail device, and send the oil pressure information to the controller; the controller is used to control the speed of the engine according to the oil pressure information, and according to the displacement information of the operating handle of the construction machinery One rail in the control common rail unit supplies oil to the working cylinders. The hydraulic control oil circuit provided by the invention can enable the engine to run at an economical speed for a long time to save energy and reduce emissions, and at the same time meet the hydraulic oil demand for instantaneous heavy loads of engineering machinery.

Description

Construction machinery and its hydraulic control oil circuit

technical field

The invention relates to the field of hydraulic oil circuits, in particular to a construction machinery hydraulic control oil circuit and construction machinery with the same.

Background technique

At present, there are many types of hydraulic oil circuits for construction machinery (such as excavators) on the market, one of which is shown in Figure 1, which uses the engine 1' to provide power to drive the hydraulic oil pump 2' to pump the hydraulic oil out of the oil tank 4' To supply oil to the working cylinder 6', the hydraulic oil pushes the piston in the working cylinder 6' to reciprocate to realize various actions of construction machinery. For example, for excavators, these actions include: boom lifting and lowering, stick Excavation and unloading of buckets, excavation and unloading of buckets, slewing and walking, etc. Of course, in actual operation, there will be two or more actions running at the same time. In order to meet the demand for hydraulic oil under such heavy load conditions, generally medium-sized and above excavators are equipped with two hydraulic oil pumps 2′. The oil pump on the market can adjust the oil supply per revolution, which is controlled by the pump oil quantity control solenoid valve 3' in the figure. When the engine 1' is overloaded, the oil supply per revolution of the oil pump 2' is reduced to prevent the engine 1' from stalling And make the engine 1' balance work at the set speed. Furthermore, the flow to the working cylinder 6' can be adjusted by the flow solenoid valve 5'.

The above-mentioned combination of the engine 1' and the oil pump 2' to directly provide the hydraulic oil has the following disadvantages:

(1) According to the above working process of the excavator, it can be seen that it has low power requirements such as bucket unloading and boom lowering, as well as high power requirements such as boom lifting and slewing. In order to ensure work efficiency, the driver often chooses one that can Generally speaking, each gear corresponds to a fixed engine speed. For this reason, the gear that is at the maximum load for a long time will cause waste of engine work and increase fuel consumption. At the same time, the engine works for a long time In the non-economic speed zone, it will also cause the deterioration of emissions;

(2) The fluctuation of the engine speed will lead to the fluctuation of oil supply, which will make the operation of the working cylinder not smooth.

Contents of the invention

In view of this, the present invention proposes a construction machinery hydraulic control oil circuit and construction machinery with it, so as to avoid problems such as high energy consumption caused by the engine being in a high-load state for a long time and reduce the impact of engine speed changes on oil supply pressure.

On the one hand, there is provided a construction machinery hydraulic control oil circuit for supplying oil to working cylinders, the construction machinery hydraulic control oil circuit includes: an engine, a first oil pump, and a controller, and the engine is connected to the first oil pump , used to drive the first oil pump to pump oil; the oil pressure at the oil outlet of the first oil pump is greater than the oil pressure at the oil inlet, and the engineering machinery hydraulic control oil circuit also includes: a common rail device and a pressure sensor; The common rail device includes at least two oil rails, the pressures in each oil rail are unequal, the oil inlet of the common rail device is connected to the oil outlet of the first oil pump, and the oil rails of each oil rail in the common rail device The oil outlet is connected to the working oil cylinder; the pressure sensor is used to sense the oil pressure information in the rail of the common rail device and send the oil pressure information to the controller; the controller is used to The engine speed is controlled by the oil pressure information, and an oil rail in the common rail device is controlled to supply oil to the working oil cylinder according to the displacement information of the operating handle of the construction machine.

Further, the common rail device includes a first oil rail, a pressure control valve, a second oil rail, a first flow control unit, and a second flow control unit; the oil inlet of the first oil rail is connected to the first The oil outlet of the oil pump, the oil outlet of the first oil rail is connected to the working oil cylinder through the first flow control unit; the oil inlet of the second oil rail is connected with the first oil inlet through the pressure control valve An oil rail is connected, and the oil outlet of the second oil rail is connected to the working oil cylinder through the second flow control unit; the pressure in the second oil rail is lower than the pressure in the first oil rail; The pressure sensor includes a first pressure sensor for sensing oil pressure information in the first oil rail and a second pressure sensor for sensing oil pressure information in the second oil rail, the first pressure sensor and the second pressure sensor are connected to the controller; the controller is used to control the opening of the first flow control unit and the second flow control unit according to the displacement information of the operating handle to control the common The first oil rail or the second oil rail in the rail device supplies oil to the working oil cylinder.

Further, the pressure control valve is a pressure electromagnetic control valve, which is connected to the controller and used to adjust its own opening according to the control information sent by the controller.

Further, the first flow control unit and the second flow control unit are flow control solenoid valves.

Further, the construction machinery hydraulic control oil circuit also includes a displacement sensor for sensing the actual displacement of the working cylinder; the displacement sensor is connected to the controller; The information determines the target displacement of the working oil cylinder, compares the actual displacement with the target displacement, and controls the opening degrees of the first flow control unit and the second flow control unit according to the comparison result.

Further, the construction machinery hydraulic control oil circuit also includes at least one of a first pressure limiting valve, a second pressure limiting valve and a third pressure limiting valve; both ends of the first pressure limiting valve are respectively connected for The oil outlet and the oil return port of the oil tank supplied by the first oil pump; the two ends of the second pressure limiting valve are respectively connected to the first oil rail and the oil return port of the oil tank; the third pressure limiting valve Two ends of the pressure valve are respectively connected to the second oil rail and the oil return port of the oil tank.

Further, the construction machinery hydraulic control oil circuit further includes a pump oil volume control solenoid valve, and the oil inlet port of the first oil pump is connected to the oil outlet port of the oil tank through the pump oil volume control solenoid valve.

Further, a second oil pump is arranged in the oil tank, and the oil outlet of the second oil pump is used as the oil outlet of the oil tank, and is connected to the pump oil volume control solenoid valve.

In another aspect, the present invention provides a construction machine, which is provided with the hydraulic control oil circuit of the construction machine.

Further, the construction machine includes an excavator.

The construction machinery hydraulic control oil circuit of the present invention is a brand-new oil supply system formed by adding a common rail device between the oil pump and the working oil cylinder of the prior art, and a pressure sensor for sensing the oil pressure in the rail. The common rail device The engine speed control and the hydraulic demand of the working cylinder can be separated and independent. The engine speed control is directly controlled by the actual pressure of the common rail device, and the hydraulic demand of the working cylinder is controlled by the operating handle, so that the engine can be operated at an economical speed for a long time to achieve energy saving and Reduce emissions, and at the same time meet the hydraulic oil demand of construction machinery with large instantaneous loads; at the same time, because the pressure of the common rail device is stable, the pressure source of the working cylinder is determined by the common rail device, so that the impact of engine speed changes on the oil supply pressure is small.

Since the engineering machinery has the corresponding technical effects of the hydraulic control oil circuit of the above-mentioned engineering machinery, it will not be repeated here.

Description of drawings

The drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is a structural schematic diagram of an existing engineering machinery hydraulic control oil circuit;

Fig. 2 is a schematic structural diagram of a construction machinery hydraulic control oil circuit provided by an embodiment of the present invention.

detailed description

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

Fig. 2 is a structural schematic diagram of the construction machinery hydraulic control oil circuit provided by the embodiment of the present invention; as shown in Fig. 2, the construction machinery hydraulic control oil circuit is used for supplying oil to the working cylinder 11, and the construction machinery hydraulic control oil circuit includes: Engine 1, first oil pump 2, first oil rail 5, second oil rail 6, first pressure sensor 71, second pressure sensor 72, pressure control valve 8, first flow control unit 101, second flow control unit 102 , Controller 13.

Wherein, the engine 1 is connected with the first oil pump 2 for driving the first oil pump 2 to pump oil; the oil pressure at the oil outlet of the first oil pump 2 is greater than the oil pressure at the oil inlet (that is, the first oil pump 2 can be called high pressure oil pump), the oil inlet of the first oil rail 5 is connected to the oil outlet of the first oil pump 2, and the oil outlet of the first oil rail 5 is connected to the working oil cylinder 11 through the first flow control unit 101; the inlet of the second oil rail 6 The oil port is connected to the first oil rail 5 through the pressure control valve 8, and the oil outlet of the second oil rail 6 is connected to the working oil cylinder 11 through the second flow control unit 102; the pressure in the second oil rail 6 is lower than that of the first oil rail The pressure in the 5 rails, correspondingly, the second oil rail 6 and the first oil rail 5 can be called the low-pressure oil rail and the high-pressure oil rail respectively; the first pressure sensor 71 is used to sense the oil pressure in the first oil rail 5 Information, the second pressure sensor 72 is used to sense the oil pressure information in the rail of the second oil rail 6, the first pressure sensor 71 and the second pressure sensor 72 are connected with the controller 13 (in order to simplify the diagram in Fig. 1, only The connection relationship between the second pressure sensor 72 and the controller 13 is shown).

The above-mentioned controller 13 is used to control the speed of the engine 1 according to the oil pressure information, and is used to control the opening of the first flow control unit 101 and the second flow control unit 102 according to the displacement information of the operating handle, thereby controlling the first oil rail 5 or the second oil rail 6 supplies oil to the working oil cylinder 11.

Preferably, the pressure control valve 8 may be a pressure electromagnetic control valve, which is connected to the controller 13 (for the sake of simplification of the diagram, the connection relationship is not shown), and is used to adjust itself according to the control information sent by the controller 13. opening. In this way, the automatic regulation of the pressure in the second oil rail 6 can be realized through the control information of the controller 13 .

Preferably, in order to realize the automatic adjustment of the flow rate flowing into the working cylinder 11, the first flow control unit 101 and the second flow control unit 102 are flow control solenoid valves.

Preferably, the above-mentioned construction machinery hydraulic control oil circuit may also include a displacement sensor 12, which is used to sense the actual displacement of the working cylinder 11; the displacement sensor 12 is connected to the controller 13, and the controller 13 is used to determine according to the displacement information of the operating handle. The target displacement of the working oil cylinder 11 is compared with the actual displacement and the target displacement, and the opening degrees of the first flow control unit 101 and the second flow control unit 102 are controlled according to the comparison result. In this way, through the sensing of the actual displacement, the first oil rail 5 or the second oil rail 6 can be selected as The working oil cylinder 11 supplies oil, and can control the oil supply flow rate, thereby realizing precise control of the movement of the working oil cylinder 11, avoiding the oil pump 2' to continue to supply oil even when the oil cylinder 11' reaches the limit position in the prior art as shown in Figure 1 Oil leads to the defect of energy waste, or avoid the energy loss caused by the hydraulic oil flowing out from the throttling bypass (not shown) when the oil cylinder 11 ′ reaches the limit position as shown in FIG. 1 .

Preferably, the construction machinery hydraulic control oil circuit may further include at least one of the first pressure limiting valve 41, the second pressure limiting valve 42 and the third pressure limiting valve 43; both ends of the first pressure limiting valve 41 are respectively connected to the oil tank 13 oil outlet and oil return port; the two ends of the second pressure limiting valve 42 are respectively connected to the first oil rail 5 and the oil return port of the oil tank 13; the two ends of the third pressure limiting valve 43 are respectively connected to the second oil rail 6 Oil return port with oil tank 13. Wherein, the oil tank 13 is used for supplying oil to the first oil pump 2 . In this way, when the construction machinery (such as an excavator) has no load, the hydraulic oil at the oil outlet of the oil tank 13 will flow back to the oil tank 13 through the first pressure limiting valve 41; the second pressure limiting valve 42 and the third pressure limiting valve 43 respectively The first oil rail 5 and the second oil rail 6 play the role of safety protection.

During specific operation, the engineering machinery hydraulic control oil circuit may also include a pump oil volume control solenoid valve 3, and the oil inlet of the first oil pump 2 is connected to the oil outlet of the oil tank 13 through the pump oil volume control solenoid valve 3. A second oil pump 9 may also be arranged in the fuel tank 13, and the oil outlet of the second oil pump 9 is used as the oil outlet of the fuel tank 13, and is connected to the solenoid valve 3 for controlling the amount of pumped oil.

The working principle of the above construction machinery hydraulic control oil circuit is briefly described as follows: the stable pressure values of the first oil rail 5 and the second oil rail 6 can be set according to the model of the construction machinery and the actual needs, such as stabilizing the first oil rail 5 When the pressure is set to 35Mpa, the oil pressure when the second oil rail 6 is stable is set to 16Mpa; driven by the engine 1, the first oil pump 2 converts the low-pressure oil provided by the second oil pump 9 into high-pressure oil and pumps it to the first The oil rail 5 and the speed of the engine 1 are determined according to the actual pressure in the first oil rail 5. For example, when the construction machinery has no load, the pressure stability can be controlled at the idle speed of the engine, and at the same time reduce the pump oil volume to control the opening of the solenoid valve 3 or even Closed, the low-pressure oil from the second oil pump 9 will flow back to the oil tank 13 through the first pressure limiting valve 41; when the rail pressure of the first oil rail 5 fluctuates within the range of 2Mpa-7Mpa below the set value, the engine speed can be set Run at the economic speed value (the meaning of the economic speed value is to control the engine speed in the speed range with low fuel consumption value according to the universal characteristic curve of the engine), when the rail pressure fluctuation of the first oil rail 5 exceeds the set value When the engine speed is 7Mpa, the engine speed can be controlled at the operating point of high power and high speed for a short time until the rail pressure of the first oil rail 5 is stable; the second pressure limiting valve 42 of the first oil rail 5 only causes the first oil Only when the rail pressure of the rail 5 is out of control, it will play a role. Similarly, the third pressure limiting valve 43 of the second oil rail 6 will only play a role when the rail pressure of the second oil rail 6 is out of control due to a system abnormality. After the oil pressure in the first oil rail 5 and the second oil rail 6 is established, the controller 13 determines the target displacement of the working oil cylinder 11 according to the displacement signal of the operating handle, and controls the flow control unit 101 and the flow control unit 101 according to the feedback value of the displacement sensor 12. 102 to select the first oil rail 5 or the second oil rail 6 to realize the high-speed and smooth operation of the working oil cylinder 11. It can be seen that the control core of the controller 13 is to control the rail pressures of the first oil rail 5 and the second oil rail 6 to stabilize at the set value.

It can be understood that the construction machinery hydraulic control oil circuit in the above embodiment adopts a specific form of a common rail device, which includes the first oil rail 5, the pressure control valve 8, the second oil rail 6, and the first flow control unit 101 , the second flow control unit 102; wherein, the pressure control valve 8 can realize the different pressure adjustments in the first oil rail 5 and the second oil rail 6; the first flow control unit 101 and the second flow control unit 102 are for convenient adjustment The flow rate of the oil outlets of the first oil rail 5 and the second oil rail 6 can be selected according to actual needs; according to actual needs, the specific setting form of the common rail device can be changed, such as adjusting the number of oil rails and the pressure difference of each oil rail For example, the number of oil rails in the common rail device can be set to three, one of which is directly connected to the oil outlet of the first oil pump 2 through the pressure control valve, and the other oil rail is directly connected to the first The oil outlet of the oil pump 2 is connected, and the third oil rail is directly connected with the oil outlet of the fuel tank 13; of course, corresponding to the change of the number of oil rails, the number of pressure sensors used to sense the oil pressure information in the oil rail also corresponds Variety. In the embodiment shown in Fig. 2, two working oil cylinders 11 are schematically provided. Correspondingly, the first oil rail 5 has two output ports and the second oil rail 6 has two output ports corresponding to the two working oil cylinders 11 respectively. , each output port of the first oil rail 5 is provided with a first flow control unit 101, and each output port of the second oil rail 6 is provided with a second flow control unit 102; during specific operation, the number of working cylinders 11 The number of output ports of the first oil rail 5 and the second oil rail 6 and the number of the first flow control unit 101 and the second flow control unit 102 can be adjusted as required.

The hydraulic control oil circuit of construction machinery in the present invention adds a first oil rail and a second oil rail between the oil pump and the working oil cylinder in the prior art, and forms a brand new oil supply system with a pressure sensor for sensing the two oil rails , where the first oil rail is supplied with oil by the oil pump, and the second oil rail is supplied with oil by the first oil rail. This secondary common rail of hydraulic oil can separate the engine speed control from the hydraulic demand of the working cylinder, and the engine speed control is directly controlled by the second oil rail. The actual pressure of the oil rail is controlled, and the hydraulic pressure demand of the working oil cylinder is controlled according to the operating handle, so that the engine can be operated at an economical speed for a long time to achieve energy saving and reduce emissions, and at the same time, it can meet the hydraulic oil demand of the construction machinery for a momentary heavy load; preferably, Using the signal of the displacement sensor of the working cylinder as feedback, the combination of the two-stage common rail and the displacement sensor of the working cylinder can realize the precise control of the working cylinder, and control the oil supply after the cylinder is in place, so as to prevent energy loss and make the movement of the cylinder smooth Controllable, increasing the comfort of the driver's operation.

In an embodiment not shown, the present invention also provides a construction machine, which is provided with the hydraulic control oil circuit of the construction machine mentioned above. Specifically, the engineering machinery includes but is not limited to excavators. Since the engineering machinery has the corresponding technical effects of the above-mentioned hydraulic control oil circuit, it will not be repeated here.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (9)

1. A construction machinery hydraulic control oil circuit, used for supplying oil to a working oil cylinder (11), said construction machinery hydraulic control oil circuit comprising: an engine (1), a first oil pump (2), a controller (13), The engine (1) is connected to the first oil pump (2) for driving the first oil pump (2) to pump oil; the oil pressure at the oil outlet of the first oil pump (2) is greater than that at the oil inlet Oil pressure, characterized in that the construction machinery hydraulic control oil circuit also includes: a common rail device and a pressure sensor; The common rail device includes at least two oil rails, the pressures in each oil rail are unequal, the oil inlet of the common rail device is connected to the oil outlet of the first oil pump (2), and in the common rail device The oil outlets of each oil rail are connected to the working oil cylinder (11); The pressure sensor is used to sense the oil pressure information in the rail of the common rail device, and send the oil pressure information to the controller (13); The controller (13) is used to control the rotational speed of the engine (1) according to the oil pressure information, and to control one oil rail in the common rail device to perform the work according to the displacement information of the operating handle of the engineering machinery. Oil cylinder (11) supplies oil; The common rail device includes a first oil rail (5), a pressure control valve (8), a second oil rail (6), a first flow control unit (101), and a second flow control unit (102); The oil inlet port of an oil rail (5) is connected to the oil outlet port of the first oil pump (2), and the oil outlet port of the first oil rail (5) is connected to the The working oil cylinder (11); the oil inlet of the second oil rail (6) is connected with the first oil rail (5) through the pressure control valve (8), and the second oil rail (6) The oil outlet of the oil outlet is connected to the working oil cylinder (11) through the second flow control unit (102); the pressure in the second oil rail (6) is lower than that in the first oil rail (5) pressure; The pressure sensor includes a first pressure sensor (71) for sensing oil pressure information in the first oil rail (5) and a first pressure sensor (71) for sensing oil pressure information in the second oil rail (6). The second pressure sensor (72), the first pressure sensor (71) and the second pressure sensor (72) are all connected with the controller (13); The controller (13) is used to control the opening of the first flow control unit (101) and the second flow control unit (102) according to the displacement information of the operating handle, so as to control the The first oil rail (5) or the second oil rail (6) supplies oil to the working oil cylinder (11). 2. The construction machinery hydraulic control oil circuit according to claim 1, characterized in that, the pressure control valve (8) is a pressure electromagnetic control valve, which is connected with the controller (13) for controlling The control information sent by the device (13) adjusts its own opening. 3. The construction machinery hydraulic control oil circuit according to claim 2, characterized in that, the first flow control unit (101) and the second flow control unit (102) are flow control solenoid valves. 4. The construction machinery hydraulic control oil circuit according to any one of claims 1-3, further comprising a displacement sensor (12) for sensing the actual displacement of the working oil cylinder (11); A displacement sensor (12) is connected to the controller (13); The controller (13) is used to determine the target displacement of the working oil cylinder (11) according to the displacement information of the operating handle, compare the actual displacement with the target displacement, and control the The opening degrees of the first flow control unit (101) and the second flow control unit (102). 5. According to the construction machinery hydraulic control oil circuit described in claim 4, it is characterized in that it also includes the first pressure limiting valve (41), the second pressure limiting valve (42) and the third pressure limiting valve (43). at least one; Both ends of the first pressure limiting valve (41) are respectively connected to the oil outlet and the oil return port of the oil tank (13) for supplying oil to the first oil pump (2); Both ends of the second pressure limiting valve (42) are respectively connected to the oil return port of the first oil rail (5) and the oil tank (13); Both ends of the third pressure limiting valve (43) are respectively connected to the oil return port of the second oil rail (6) and the oil tank (13). 6. According to claim 5, the construction machinery hydraulic control oil circuit is characterized in that it also includes a pump oil volume control solenoid valve (3), and the oil inlet of the first oil pump (2) passes through the pump oil volume The control solenoid valve (3) is connected with the oil outlet of the oil tank (13). 7. The construction machinery hydraulic control oil circuit according to claim 6, characterized in that, a second oil pump (9) is arranged in the oil tank (13), and the oil outlet of the second oil pump (9) serves as the The oil outlet of the oil tank (13) is connected to the pump oil volume control solenoid valve (3). 8. A construction machine, characterized in that it is provided with a construction machine hydraulic control oil circuit according to any one of claims 1-7. 9. A construction machine according to claim 8, comprising an excavator.