CN219570463U

CN219570463U - Hydraulic control system and engineering vehicle

Info

Publication number: CN219570463U
Application number: CN202321037372.2U
Authority: CN
Inventors: 唐标; 欧中林; 黄爽; 张成兰
Original assignee: Zoomlion Earth Moving Machinery Co Ltd; Shaanxi Zoomlion West Earthmoving Machinery Co Ltd
Current assignee: Zoomlion Earth Moving Machinery Co Ltd; Shaanxi Zoomlion West Earthmoving Machinery Co Ltd
Priority date: 2023-05-04
Filing date: 2023-05-04
Publication date: 2023-08-22
Anticipated expiration: 2033-05-04

Abstract

The utility model provides a hydraulic control system and an engineering vehicle, wherein the system comprises: the hydraulic main pump comprises a first load feedback oil port; the hydraulic main valve comprises a second load feedback oil port; the first oil port of the multi-way valve is communicated with the first load feedback oil port, and the second oil port of the multi-way valve is communicated with the second load feedback oil port; the normally closed hydraulic control switch is communicated with the third oil port of the multi-way valve, and is disconnected when the pressure of hydraulic oil transmitted to the normally closed hydraulic control switch is greater than a preset pressure; and a controller electrically connected to the normally closed hydraulic control switch configured to: when the normally closed hydraulic control switch is disconnected, a non-idle speed control instruction is sent to the engine control unit; when the normally closed hydraulic control switch is closed, an idle speed control command is sent to the engine control unit. Compared with the hardware cost for controlling the engine rotation speed by using the pressure sensor and the controller, the hardware cost is lower, the control logic is simpler, and the cost of after-sales maintenance is reduced.

Description

Hydraulic control system and engineering vehicle

Technical Field

The utility model relates to the technical field of hydraulic control, in particular to a hydraulic control system and an engineering vehicle.

Background

When the actuating mechanism of the engineering machinery moves, the hydraulic oil in the hydraulic control system for providing hydraulic energy for the actuating mechanism can be far higher than the pressure when the actuating mechanism does not move, and the engine needs to drive the hydraulic main pump at a higher rotating speed at the moment so that the hydraulic main pump can output enough high-pressure hydraulic oil to meet the working requirement of the actuating mechanism. However, when the actuator is stationary, the hydraulic oil pressure in the hydraulic control system is significantly reduced, and if the engine is kept running at a high rotational speed, the idle work is increased, and the fuel consumption is increased.

In the prior art, when detecting the internal pressure of a hydraulic system pipeline, a pressure sensor is generally adopted to detect the pressure of the hydraulic system pipeline and transmit the pressure to a controller, the controller analyzes signals transmitted by the pressure sensor, determines the state of an actuating mechanism according to the pressure of hydraulic oil, and further controls other devices to work. When the controller detects that the pressure of the hydraulic control system of the engineering vehicle is too low, the controller can judge that the engineering vehicle is in an unoperated state, and then can control the engine to reduce the rotating speed and enter an idle state. However, the hardware cost for detecting the pressure by the pressure sensor and further controlling whether the engine enters an idle state is too high, and the controller needs to analyze the signal transmitted by the pressure sensor to control. In addition, because the electronic device has a complex structure, the electronic device generally needs to be replaced integrally under the condition of failure, and the after-sale maintenance cost is high.

Disclosure of Invention

The embodiment of the utility model aims to provide a hydraulic control system and an engineering vehicle, which are used for solving the technical problem that the cost for detecting the pipeline pressure of a hydraulic system is too high in the prior art.

To achieve the above object, a first aspect of the present utility model provides a hydraulic control system including:

the hydraulic main pump comprises a first load feedback oil port;

the hydraulic main valve comprises a second load feedback oil port;

the first oil port of the multi-way valve is communicated with the first load feedback oil port, and the second oil port of the multi-way valve is communicated with the second load feedback oil port;

the normally closed hydraulic control switch is communicated with the third oil port of the multi-way valve, and is disconnected when the pressure of hydraulic oil transmitted to the normally closed hydraulic control switch is greater than a preset pressure; and

and a controller electrically connected with the normally closed hydraulic control switch and configured to:

when the normally closed hydraulic control switch is disconnected, a non-idle speed control instruction is sent to the engine control unit;

when the normally closed hydraulic control switch is closed, an idle speed control command is sent to the engine control unit.

In an embodiment of the present utility model, a normally closed hydraulic control switch includes: a housing; and is arranged in the shell: the limiting sleeve is internally provided with a cavity, the bottom of the limiting sleeve is provided with an opening, and two contacts which can be mutually connected or disconnected are arranged on the limiting sleeve; an elastic member; and the movable piece is movably penetrated through the opening and inserted into the cavity, the bottom end of the movable piece is connected with the hydraulic oil port, an elastic piece is elastically compressed between the top end of the movable piece and the top wall of the limiting sleeve, and when the hydraulic oil pressure applied to the bottom end of the movable piece is greater than the preset pretightening force of the elastic piece, the movable piece is separated from the two contacts.

In an embodiment of the utility model, the controller is electrically connected to both contacts and is configured to: when the two contacts are conducted, an idle speed control instruction is sent to the engine control unit; and when the two contacts are disconnected, sending a non-idle speed control instruction to the engine control unit.

In an embodiment of the utility model, the normally closed hydraulic control switch further comprises: the elastic diaphragm is arranged in the shell and is positioned between the bottom end of the movable piece and the hydraulic oil port.

In the embodiment of the utility model, a pressure measuring port is formed in the shell, one side of the pressure measuring port is communicated with the hydraulic oil way, and the other side of the pressure measuring port is abutted against the elastic diaphragm.

In the embodiment of the utility model, the movable piece comprises a vertical rod, a transverse baffle plate arranged at the top end of the vertical rod and a plug arranged at the bottom end of the vertical rod, the transverse baffle plate is positioned in the cavity, the length of the transverse baffle plate is larger than the maximum length of the opening, and the plug is abutted with one side of the elastic diaphragm, which is away from the pressure measuring port.

In the embodiment of the utility model, the limit sleeve comprises a top wall, a side wall and a step part extending from the bottom end of the side wall in opposite directions, an opening is formed between the two step parts, and the contact is arranged on the step part.

In an embodiment of the utility model, the hydraulic control system further comprises: the first damping oil port of the pulse damper is connected with the third oil port, and the second damping oil port of the pulse damper is connected with the normally closed hydraulic control switch.

The second aspect of the utility model provides an engineering vehicle comprising the hydraulic control system.

In an embodiment of the utility model, the engineering vehicle further comprises an engine and an engine control unit, wherein the engine control unit is used for controlling the rotating speed of the engine according to the control instruction sent by the controller.

Through the technical scheme, the hydraulic control system provided by the embodiment of the utility model has the following beneficial effects:

according to the utility model, the pressure of hydraulic oil in the hydraulic pipeline is detected through the normally closed hydraulic control switch, when the hydraulic oil transmitted to the normally closed hydraulic control switch is larger than the preset pressure, the normally closed hydraulic control switch is disconnected, and a controller connected with the normally closed hydraulic control switch can send a non-idle speed instruction to the engine control unit. When the hydraulic oil transmitted to the normally closed hydraulic control switch is smaller than or equal to the preset pressure, the normally closed hydraulic control switch is closed, and a controller connected with the normally closed hydraulic control switch can send an idling command to the engine control unit. The engine control unit may control the engine speed in accordance with instructions sent by the controller. Compared with the mode of controlling the engine speed by using the pressure sensor and the controller, the hydraulic control system has the advantages of lower hardware cost, simpler control logic and reduced after-sale maintenance cost.

Additional features and advantages of the utility model will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide an understanding of the utility model, and are incorporated in and constitute a part of this specification, illustrate the utility model and together with the description serve to explain, without limitation, the utility model. In the drawings:

FIG. 1 is a block diagram of a hydraulic control system according to one embodiment of the present utility model;

FIG. 2 is a block diagram of an engineering vehicle in accordance with one embodiment of the present utility model;

FIG. 3 is a schematic diagram of a normally closed hydraulic control switch according to an embodiment of the present utility model;

fig. 4 is a schematic view of a movable member according to an embodiment of the present utility model.

Description of the reference numerals

Reference numerals	Name of the name	Reference numerals	Name of the name
				1	Hydraulic main pump	4D1	Vertical rod
2	Hydraulic main valve	4D2	Transverse baffle
				3	Multi-way valve	4D3	Plug head
4	Normally closed hydraulic control switch	4E	Elastic membrane
				4A	Shell body	5	Controller for controlling a power supply
4A1	Pressure measuring port	10	Hydraulic control system
				4B	Limiting sleeve	20	Engine control unit
4B1	Contact point	30	Engine with a motor
				4C	Elastic piece	100	Engineering vehicle
4D	Movable piece

Detailed Description

Specific embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present utility model.

The hydraulic control system 10 and the working vehicle 100 according to the present utility model are described below with reference to the drawings.

As shown in fig. 1, in an embodiment of the present utility model, there is provided a hydraulic control system 10 including:

the hydraulic main pump 1 comprises a first load feedback oil port.

The hydraulic main valve 2 comprises a second load feedback port.

The first oil port of the multi-way valve 3 is communicated with the first load feedback oil port, and the second oil port of the multi-way valve 3 is communicated with the second load feedback oil port.

A controller 5 electrically connected to the normally closed hydraulic control switch 4 and configured to: when the normally closed hydraulic control switch 4 is turned off, a non-idle control instruction is sent to the engine control unit 20. When the normally closed hydraulic control switch 4 is closed, an idle speed control instruction is sent to the engine control unit 20.

The pressure within the hydraulic control system 10 is typically sensed by a pressure sensor in the prior art, and the rotational speed of the engine 30 is controlled based on the sensed hydraulic oil pressure. The present utility model is applied to the construction vehicle 100 shown in fig. 2, and includes a hydraulic control system 10, an engine control unit 20, and an engine 30. Engine 30 typically includes an idle state and a non-idle state. When the engine control unit 20 controls the engine 30 to be in an idle state, the rotation speed of the engine 30 is within a preset rotation speed range. When the engine control unit 20 controls the engine 30 to be in a non-idle state, the engine control unit 20 may control the rotational speed of the engine 30 according to the accelerator gear.

The hydraulic main pump 1 can provide high-pressure hydraulic oil for the hydraulic control system 10 and drive the executing mechanism to move. The hydraulic main valve 2 can control the pressure, flow and direction of hydraulic oil, and further control the movement of an actuating mechanism. The hydraulic main valve 2 may feed back hydraulic oil to the second load feedback port of the hydraulic main pump 1 through the first load feedback port, so that the hydraulic main pump 1 determines the hydraulic oil pressure from the fed-back hydraulic oil. The multi-way valve 3 is a hydraulic valve including a plurality of oil ports, the inside of which can be conducted, and the pressure of hydraulic oil at each of the oil ports is the same. The normally closed hydraulic control switch 4 is a switch for controlling internal on-off according to the received pressure, and when the received pressure is greater than the preset pressure, the normally closed hydraulic control switch 4 is opened, and when the received pressure is less than or equal to the preset pressure, the normally closed hydraulic control switch 4 is opened and kept closed.

Further, the multi-way valve 3 may transmit the hydraulic oil in the load oil path formed between the hydraulic main valve 2 and the hydraulic main pump 1 to the normally closed hydraulic control switch 4. When the pressure of the hydraulic oil input to the normally closed hydraulic control switch 4 is greater than the preset pressure, the normally closed hydraulic control switch 4 may be turned off. The controller 5 may send a non-idle control command to the engine control unit 20 when the normally closed hydraulic control switch 4 is turned off, so that the engine control unit 20 controls the rotation speed of the engine 30. When the pressure of the hydraulic oil input to the normally closed hydraulic control switch 4 is less than or equal to the preset pressure, the normally closed hydraulic control switch 4 may be kept closed. The controller 5 may send an idle speed command to the engine control unit 20 when the normally closed hydraulic control switch 4 is closed, so that the engine control unit 20 controls the rotational speed of the engine 30 to be adjusted within a preset range.

In other words, the present utility model detects the pressure of the hydraulic oil in the hydraulic line through the normally closed hydraulic control switch 4, and when the hydraulic oil transferred to the normally closed hydraulic control switch 4 is greater than the preset pressure, the normally closed hydraulic control switch 4 is turned off, and the controller 5 connected to the normally closed hydraulic control switch 4 may send a non-idle command to the engine control unit 20. When the hydraulic oil transmitted to the normally closed hydraulic control switch 4 is less than or equal to the preset pressure, the normally closed hydraulic control switch 4 is closed, and the controller 5 connected to the normally closed hydraulic control switch 4 may send an idle speed command to the engine control unit 20. The engine control unit 20 may control the rotational speed of the engine 30 according to instructions sent from the controller 5. Compared with the mode of using the pressure sensor and the controller to control the rotation speed of the engine, the hydraulic control system 10 provided by the utility model has the advantages that the hardware cost is lower, the control logic is simpler, and the after-sale maintenance cost is reduced.

In one embodiment, as shown in fig. 3, a schematic diagram of a structure of a normally closed hydraulic control switch 4 is shown, where the normally closed hydraulic control switch 4 includes a housing 4A, and a stop collar 4B, an elastic member 4C, and a movable member 4D disposed in the housing 4A. The limiting sleeve 4B is provided with a cavity inside and an opening at the bottom, and two contacts 4B1 which can be mutually connected or disconnected are arranged on the limiting sleeve 4B. The movable piece 4D is movably penetrated through the opening and inserted into the cavity, the bottom end of the movable piece 4D is connected with the hydraulic oil port, the elastic piece 4C is elastically compressed between the top end of the movable piece 4D and the top wall of the limit sleeve 4B, and when the hydraulic oil pressure applied to the bottom end of the movable piece 4D is larger than the preset pretightening force of the elastic piece 4C, the movable piece 4D is separated from the two contacts 4B1.

The housing 4A is a protection part of the normally closed hydraulic control switch 4, and the cavity inside the housing 4A contains a part for preventing the part inside the housing 4A from moving to be damaged. The elastic member 4C refers to a part that can be expanded or contracted, such as a spring. The limiting sleeve 4B can limit the movement range of the elastic member 4C and/or the movable member 4D so as to move within a preset range. The inside of the spacer 4B has a cavity and the bottom has an opening so that the movable member 4D can move inside the cavity of the spacer 4B. The contact 4B1 may also be referred to as a power-on point, and when the movable member 4D is connected to both the contacts 4B1, both the contacts 4B1 are turned on; when the movable member 4D is separated from the two contacts 4B1, the two contacts 4B1 are turned on and off. The on and off of the contact 4B1 can turn on and off the normally closed hydraulic control switch 4. The movable part 4D is a part which can move inside the switch, the movable part 4D penetrates through the opening of the limit sleeve 4B and is inserted into the cavity of the limit sleeve 4B, the bottom end of the movable part 4D is connected with the hydraulic oil port, and the elastic part 4C is elastically compressed between the top end of the movable part 4D and the top wall of the limit sleeve 4B. When the pressure of hydraulic oil applied to the bottom end of the movable part 4D is greater than the preset pretightening force of the elastic part 4C, the elastic part 4C is compressed under pressure, and the movable part 4D can be separated from the contact 4B1 installed on the limit sleeve 4B, so that the contact 4B1 is disconnected and connected, and the normally closed hydraulic control switch 4 is disconnected.

Therefore, by using the normally closed hydraulic control switch 4 described above, the movable member 4D can be separated from the contact 4B1 when the hydraulic oil pressure in the hydraulic system is greater than the preset pretightening force, and the movable member 4D can be abutted against the contact 4B1 when the hydraulic oil in the hydraulic control system 10 is less than or equal to the preset pretightening force. When the pressure of the normally open hydraulic control switch is larger than the preset pretightening force, the movable piece 4D is abutted against the contact 4B1, the pressure of hydraulic oil received by the contact 4B1 fluctuates, the pressure is large, and the contact 4B1 is easy to damage. The normally closed hydraulic control switch 4 used in the utility model can prolong the service life of the switch and ensure the stable operation of the hydraulic control system 10.

In one embodiment, the controller 5 is electrically connected to both contacts 4B1 and is configured to: when the two contacts 4B1 are turned on, an idle speed control instruction is sent to the engine control unit 20; when the two contacts 4B1 are opened, a non-idle control instruction is sent to the engine control unit 20. The controller 5 may be electrically connected to both of the contacts 4B1, and when both of the contacts 4B1 are turned on, the controller 5 may send an idle speed control command to the engine control unit 20, so that the engine control unit 20 adjusts the rotation speed of the engine 30, and the rotation speed of the engine 30 is in a rotation speed range corresponding to the idle state. When the two contacts 4B1 are opened, the controller 5 may send a non-idle control instruction to the engine control unit 20, and the engine control unit 20 may control the rotation speed of the engine 30 to a rotation speed corresponding to the accelerator gear.

In one embodiment, the normally closed hydraulic control switch 4 further comprises: the elastic diaphragm 4E is arranged in the shell 4A, and the elastic diaphragm 4E is positioned between the bottom end of the movable piece 4D and the hydraulic oil port. The elastic membrane 4E is a sealing piece capable of being pressed and deformed, and can prevent hydraulic oil from entering the inner cavity of the shell 4A of the normally closed hydraulic control switch 4. When the hydraulic oil pressure received by the bottom of the elastic membrane 4E is greater than the preset pretightening force of the elastic member 4C, the elastic member 4C can be extruded by the movable member 4D by deformation, so that the elastic member 4C is separated from the contact 4B1.

In one embodiment, the casing 4A is provided with a pressure measuring port 4A1, one side of the pressure measuring port 4A1 is communicated with the hydraulic oil path, and the other side is abutted against the elastic diaphragm 4E. Hydraulic oil is transferred to the elastic diaphragm 4E of the housing 4A through the pressure measuring port 4A1.

In one embodiment, as shown in fig. 4, the movable member 4D may move inside the closed hydraulic control switch, where the movable member 4D includes a vertical rod 4D1, a lateral baffle 4D2 installed at the top end of the vertical rod 4D1, and a plug 4D3 installed at the bottom end of the vertical rod 4D1, the lateral baffle 4D2 is located in the cavity, and the plug 4D3 abuts against a side of the elastic membrane 4E facing away from the pressure measuring port 4A1. And, the length of the transverse baffle 4D2 is longer than the maximum length of the opening of the limit sleeve 4B, so as to prevent the transverse baffle 4D2 of the movable piece 4D from being separated from the cavity to cause the clamping stagnation of the movable piece 4D. The plug 4D3 of the movable member 4D abuts against one side of the elastic diaphragm 4E away from the pressure measuring port 4A1, so that the movable member 4D is pushed to compress the elastic member 4C when the elastic diaphragm 4E is elastically deformed, and the movable member 4D is separated from the contact 4B1 on the limit sleeve 4B.

In one embodiment, the stop collar 4B includes a top wall, a side wall, and a step portion extending from a bottom end of the side wall in opposite directions, an opening is formed between the two step portions, and the contact 4B1 is disposed on the step portion. The inner cavity of the limit sleeve 4B can limit the movable range of the transverse baffle 4D2 of the movable piece 4D. The contact 4B1 may be mounted on the step portion, and when the lateral baffle 4D2 of the movable member 4D moves, the lateral baffle 4D2 of the movable member 4D may be separated from or abutted against the contact 4B1, so that the contact 4B1 is turned on or off.

In one embodiment, hydraulic control system 10 further includes: the first damping oil port of the pulse damper is connected with the third oil port, and the second damping oil port of the pulse damper is connected with the normally closed hydraulic control switch 4. The pulse damper is a hydraulic element capable of reducing pressure fluctuation, making the pressure fluctuation transmitted to the normally closed hydraulic control switch 4 gentle, and preventing impact on the normally closed hydraulic control switch 4. Since the working vehicle 100 is usually continuously operated during the working process, there is a pressure fluctuation during the working process, and the pressure may be reduced below the preset pressure in a very short time, but at this time, the actuator of the working vehicle 100 will not stop working, so if the rotation speed of the engine 30 of the working vehicle 100 is reduced, the working vehicle 100 may be unstable to operate. In view of this, the addition of the pulse damper makes it possible to smooth the pressure of the hydraulic oil transmitted to the hydraulic control switch, make the work vehicle 100 operate smoothly, and in addition, reduce the number of state switching times of the normally closed hydraulic control switch 4, and prolong the service life.

For a further detailed understanding of the operation of the normally closed hydraulic control switch 4 of the present utility model in the hydraulic control system 10, the operation is described in detail as follows:

in a specific embodiment, the hydraulic control system 10 used in the present utility model is applied to automatic idle speed control of an excavator, and when an actuator of the excavator works, for example, the excavator performs excavation and crushing, the hydraulic oil pressure of the hydraulic control system in the excavator is generally greater than 100bar, and when the actuator of the excavator stops working, the hydraulic oil pressure in the excavator is significantly reduced, typically less than 5bar, and at this time, the engine 30 can be controlled to enter an idle state, and the rotation speed of the engine 30 is reduced. The preset pretightening force of the elastic piece 4C can be set according to the pressure of hydraulic oil, and can be compressed when the pressure of the hydraulic oil is larger than 8bar, the preset pretightening force is related to the material and the compression amount of the elastic piece 4C, the model of the normally-closed hydraulic control switch 4 can be changed, and the size of the preset pretightening force is changed. Hydraulic oil between the first load feedback oil port and the second load feedback oil port can be transmitted to a detection port 4A1 of the normally closed hydraulic control switch 4 through the three-way valve 3 and the pulse damper. When the pressure of hydraulic oil is greater than 8bar, the elastic membrane 4E of the normally closed hydraulic control switch 4 can be extruded to the movable piece 4D, the movable piece 4D transmits the pressure to the elastic piece 4C, the elastic piece 4C is compressed under pressure, and then the movable piece 4D is separated from the contact 4B1. Further, the controller 5 may send a non-idle command to the engine control unit 20 in the case where it is determined that the contact 4B1 is open, and the engine control unit 20 controls the rotation speed of the engine 30 according to the accelerator gear. When the hydraulic oil pressure is less than or equal to 8bar, the normally closed hydraulic control switch 4 will remain closed, and the movable member 4D will remain against the contact 4B1. Further, the controller 5 may send an idle command to the engine control unit 20 when the contact 4B1 is turned on, and the engine control unit 20 may control the rotational speed of the engine 30 in an idle state.

To sum up: compared with the mode of using the pressure sensor and the controller to control the rotation speed of the engine, the utility model has lower hardware cost, simple control logic and reduced after-sale maintenance cost. The normally closed hydraulic control switch 4 is adopted, so that the service life of the switch can be prolonged, and the stable operation of the hydraulic control system 10 is ensured. The pulse damper is added, so that the pressure of hydraulic oil transmitted to the hydraulic control switch tends to be gentle, the engineering vehicle 100 can stably run, the state switching times of the normally closed hydraulic control switch 4 are reduced, and the service life is prolonged.

In one embodiment, an engineering vehicle 100 is provided that includes the hydraulic control system 10 described above. Since the construction vehicle 100 adopts all embodiments of the hydraulic control system 10, all the advantages of the hydraulic control system 10 are not described in detail herein.

In one embodiment, the work vehicle 100 further includes an engine 30 and an engine control unit 20, the engine control unit 20 being configured to control the rotational speed of the engine 30 according to a control command sent by the controller 5. When the controller 5 transmits an idle speed control instruction, the engine control unit 20 may control the rotation speed of the engine 30 to be reduced to within a preset range. When the controller 5 transmits a non-idle command, the engine control unit 20 may control the rotational speed of the engine 30 according to the accelerator gear.

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

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the utility model.

Claims

1. A hydraulic control system (10), characterized by comprising:

the hydraulic main pump (1) comprises a first load feedback oil port;

the hydraulic main valve (2) comprises a second load feedback oil port;

the multi-way valve (3) is characterized in that a first oil port of the multi-way valve (3) is communicated with the first load feedback oil port, and a second oil port of the multi-way valve (3) is communicated with the second load feedback oil port;

the normally closed hydraulic control switch (4) is communicated with the third oil port of the multi-way valve (3), and when the pressure of hydraulic oil transmitted to the normally closed hydraulic control switch (4) is larger than a preset pressure, the normally closed hydraulic control switch (4) is disconnected; and

a controller (5) electrically connected to the normally closed hydraulic control switch (4) and configured to:

when the normally closed hydraulic control switch (4) is disconnected, a non-idle speed control instruction is sent to an engine control unit (20);

when the normally closed hydraulic control switch (4) is closed, an idle speed control instruction is sent to the engine control unit (20).

2. The hydraulic control system (10) according to claim 1, wherein the normally closed hydraulic control switch (4) includes:

a housing (4A); and provided in the housing (4A):

the limiting sleeve (4B) is internally provided with a cavity, the bottom of the limiting sleeve is provided with an opening, and two contacts (4B 1) which can be mutually connected or disconnected are arranged on the limiting sleeve (4B);

an elastic member (4C); and

the movable piece (4D) is movably penetrated through the opening and inserted into the cavity, the bottom end of the movable piece (4D) is connected with the hydraulic oil port, the elastic piece (4C) is elastically compressed between the top end of the movable piece (4D) and the top wall of the limit sleeve (4B), and when the hydraulic oil pressure applied to the bottom end of the movable piece (4D) is larger than the preset pretightening force of the elastic piece (4C), the movable piece (4D) is separated from the two contacts (4B 1).

3. The hydraulic control system (10) according to claim 2, wherein the controller (5) is electrically connected to both of the contacts (4B 1) and configured to:

when the two contacts (4B 1) are conducted, the idle speed control instruction is sent to the engine control unit (20);

when the two contacts (4B 1) are disconnected, the non-idle speed control instruction is sent to the engine control unit (20).

4. The hydraulic control system (10) according to claim 2, wherein the normally closed hydraulic control switch (4) further comprises:

the elastic diaphragm (4E) is arranged in the shell (4A), and the elastic diaphragm (4E) is positioned between the bottom end of the movable piece (4D) and the hydraulic oil port.

5. The hydraulic control system (10) according to claim 4, wherein the casing (4A) is provided with a pressure measuring port (4A 1), one side of the pressure measuring port (4A 1) is communicated with the hydraulic oil path, and the other side is abutted against the elastic diaphragm (4E).

6. The hydraulic control system (10) according to claim 5, wherein the movable member (4D) comprises a vertical rod (4D 1), a lateral baffle (4D 2) mounted at the top end of the vertical rod (4D 1), and a plug (4D 3) mounted at the bottom end of the vertical rod (4D 1), the lateral baffle (4D 2) is located in the cavity, and the length of the lateral baffle (4D 2) is greater than the maximum length of the opening, and the plug (4D 3) abuts against a side of the elastic diaphragm (4E) facing away from the pressure measuring port (4 A1).

7. The hydraulic control system (10) according to claim 2, wherein the spacer (4B) includes a top wall, a side wall, and stepped portions extending from bottom ends of the side walls toward each other, the opening being formed between the two stepped portions, and the contact (4B 1) being provided on the stepped portions.

8. The hydraulic control system (10) according to any one of claims 1 to 7, further comprising:

the first damping oil port of the pulse damper is connected with the third oil port, and the second damping oil port of the pulse damper is connected with the normally closed hydraulic control switch (4).

9. Engineering vehicle, characterized by comprising a hydraulic control system (10) according to any one of claims 1 to 8.

10. The working vehicle according to claim 9, further comprising an engine (30) and an engine control unit (20), the engine control unit (20) being configured to control the rotational speed of the engine (30) in accordance with a control instruction sent from the controller (5).