Loader power cut-off system

Abstract

The utility model discloses a power cut-off system of a loader, which relates to the technical field of engineering machinery and comprises a first brake pressure switch unit, the first brake pressure switch unit is sequentially connected with a unilateral diode and a first power cut-off electromagnetic valve in series, and the first power cut-off electromagnetic valve is mounted in a hydraulic oil pipeline on a gearbox; the first brake pressure switch unit comprises a first brake pressure switch and a control unit, and the first brake pressure switch is installed in a hydraulic system of a brake pedal and used for detecting hydraulic pressure borne by the brake pedal when the brake pedal is stepped down and transmitting the hydraulic pressure to the control unit; and the control unit is electrically connected with the first power cut-off electromagnetic valve. According to the utility model, the problems of poor micro-control performance, easy mistaken touch and poor driving experience of the traditional control can be solved, the power cut-off function can be more accurately controlled, and the driving safety and the operation experience are improved.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, and in particular to a power cut-off system for a loader. Background Technology

[0002] Currently, with the continuous development of the engineering vehicle market, drivers are paying more attention to maneuverability and safety. Power cut-off functions are commonly used in engineering vehicles such as loaders to improve operational safety and efficiency. Power cut-off refers to cutting off the power transmission between the engine and transmission under certain specific working conditions, causing the vehicle to lose power assistance and thus achieve deceleration or stopping. For example, the power cut-off function is typically activated during material loading operations, uphill driving, temporary parking or leaving the vehicle, and operations under complex conditions. In existing technologies, the main function controlling power cut-off is switch-type control. In engineering vehicles (such as loaders and excavators), switch-type control typically includes manual switches (such as function switches and parking switches) and automatic switches (such as limit switches and pressure switches).

[0003] In existing backhoe loaders, the power cut-off function is typically controlled by a limit switch on the foot brake pedal. A limit switch is a mechanical switch mounted on the brake pedal that triggers the power cut-off function by detecting the pedal's travel (the distance the pedal is depressed). When the driver depresses the brake pedal, the limit switch triggers the power cut-off based on the pedal's travel. For example, when the vehicle is going uphill, the driver needs to brake to control the speed or stop. If the driver only slightly depresses the brake pedal, a traditional limit switch might prematurely trigger the power cut-off function, causing the vehicle to lose power and increasing the risk of rolling away, posing a safety hazard. Furthermore, in complex working conditions (such as turning, going downhill, or operating in confined spaces), the driver needs precise control of the vehicle's power output. The limit switch's control method is relatively simple and cannot be dynamically adjusted according to actual working conditions, resulting in a poor driving experience. For example, when going uphill, the driver may need to depress the brake pedal all the way to stop the vehicle, increasing the difficulty of operation and fatigue, and making it difficult to provide precise control. Utility Model Content

[0004] To overcome the shortcomings of the existing technology, this utility model provides a loader power cut-off system that uses a pressure switch instead of a limit switch. The pressure switch precisely controls the triggering timing of the power cut-off function, avoiding accidental triggering of the power cut-off function under complex working conditions and improving the accuracy and safety of operation.

[0005] This utility model adopts the following technical solution: a loader power cut-off system, including: a first brake pressure switch unit, wherein the first brake pressure switch unit is connected in series with a unidirectional diode and a first power cut-off solenoid valve, and the first power cut-off solenoid valve is installed in the hydraulic oil line on the gearbox.

[0006] The first brake pressure switch unit includes a first brake pressure switch and a control unit. The first brake pressure switch is installed in the hydraulic system of the brake pedal and is used to detect the hydraulic pressure when the brake pedal is depressed and transmit it to the control unit.

[0007] The control unit is electrically connected to the first power cut-off solenoid valve.

[0008] Preferably, the first terminal of the first brake pressure switch unit is grounded, the second terminal of the first brake pressure switch unit is connected to the positive terminal of a unidirectional diode, and the negative terminal of the unidirectional diode is connected to the first terminal of the first power cut-off solenoid valve.

[0009] Preferably, the second end of the first power cut-off solenoid valve is connected in series with the first normally open relay and the power cut-off function switch; the power cut-off function switch controls the opening and closing of the power cut-off function by controlling the on and off of the control circuit.

[0010] Preferably, a first instrument indicator light is connected between the first brake pressure switch unit and the unidirectional diode.

[0011] It also includes: a second brake pressure switch unit, which is connected in series with a unidirectional diode and a first power cut-off solenoid valve, and the first power cut-off solenoid valve is installed in the hydraulic oil line on the gearbox;

[0012] The second brake pressure switch unit includes a second brake pressure switch and a control unit. The second brake pressure switch is installed in the hydraulic system of the brake pedal and is used to detect the hydraulic pressure when the brake pedal is depressed and transmit it to the control unit.

[0013] The control unit is electrically connected to the first power cut-off solenoid valve.

[0014] Preferably, the second brake pressure switch unit is connected in parallel with the first brake pressure switch unit.

[0015] Preferably, the first terminal of the second brake pressure switch unit is grounded, the second terminal of the second brake pressure switch unit is connected to the positive terminal of a unidirectional diode, and the negative terminal of the unidirectional diode is connected to the first terminal of the first power cut-off solenoid valve.

[0016] Preferably, a second instrument indicator light is connected between the second brake pressure switch unit and the unidirectional diode.

[0017] It also includes: a parking switch, which is connected in series with the instrument parking indicator light, a second normally open relay, and a second power cut-off solenoid valve, the second power cut-off solenoid valve being installed in the hydraulic oil line on the transmission; the parking switch transmits electrical signals to the control unit or directly controls the second normally open relay.

[0018] Preferably, both the first brake pressure switch and the second brake pressure switch are installed in the hydraulic oil lines of the hydraulic system, and each has a pressure sensor installed inside.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] 1) The function of the brake pressure switch described in this utility model is to control the circuit through the brake pressure switch to ensure that the power is cut off only when necessary; the brake pressure switch provides feedback on the power cut-off status so that the driver can clearly understand the current status of the vehicle.

[0021] 2) This utility model can achieve phased triggering. When the brake is pressed, the power cut-off function will not be triggered in the first half of the braking process. The power cut-off will only be triggered in the second half of the braking process when the pressure is greater than 0.4 MPa.

[0022] 3) The diode described in this utility model is used for signal isolation. By cutting off the mutual interference between left and right signals, the diode can prevent misoperation. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0024] Figure 1 This is a schematic diagram illustrating the working principle of the power cutting system in this utility model. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application.

[0027] As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] In a typical embodiment of this utility model, such as Figure 1 As shown, a loader power cut-off system includes: a first brake pressure switch unit, wherein the first brake pressure switch unit is connected in series with a unidirectional diode and a first power cut-off solenoid valve, and the first power cut-off solenoid valve is installed in the hydraulic oil line on the gearbox;

[0029] The first brake pressure switch unit includes a first brake pressure switch and a control unit. The first brake pressure switch is installed in the hydraulic system of the brake pedal and is used to detect the hydraulic pressure when the brake pedal is depressed and transmit it to the control unit.

[0030] The control unit is electrically connected to the first power cut-off solenoid valve.

[0031] Preferably, the first terminal of the first brake pressure switch unit is grounded, the second terminal of the first brake pressure switch unit is connected to the positive terminal of a unidirectional diode, and the negative terminal of the unidirectional diode is connected to the first terminal of the first power cut-off solenoid valve.

[0032] Preferably, the second end of the first power cut-off solenoid valve is connected in series with the first normally open relay and the power cut-off function switch; the power cut-off function switch controls the opening and closing of the power cut-off function by controlling the on and off of the control circuit.

[0033] Preferably, a first instrument indicator light is connected between the first brake pressure switch unit and the unidirectional diode.

[0034] It also includes: a second brake pressure switch unit, which is connected in series with a unidirectional diode and a first power cut-off solenoid valve, and the first power cut-off solenoid valve is installed in the hydraulic oil line on the gearbox;

[0035] The second brake pressure switch unit includes a second brake pressure switch and a control unit. The second brake pressure switch is installed in the hydraulic system of the brake pedal and is used to detect the hydraulic pressure when the brake pedal is depressed and transmit it to the control unit.

[0036] The control unit is electrically connected to the first power cut-off solenoid valve.

[0037] Preferably, the second brake pressure switch unit is connected in parallel with the first brake pressure switch unit.

[0038] Preferably, the first terminal of the second brake pressure switch unit is grounded, the second terminal of the second brake pressure switch unit is connected to the positive terminal of a unidirectional diode, and the negative terminal of the unidirectional diode is connected to the first terminal of the first power cut-off solenoid valve.

[0039] Preferably, a second instrument indicator light is connected between the second brake pressure switch unit and the unidirectional diode.

[0040] It also includes: a parking switch, which is connected in series with the instrument parking indicator light, a second normally open relay, and a second power cut-off solenoid valve, the second power cut-off solenoid valve being installed in the hydraulic oil line on the transmission; the parking switch transmits electrical signals to the control unit or directly controls the second normally open relay.

[0041] Preferably, both the first brake pressure switch and the second brake pressure switch are installed in the hydraulic oil lines of the hydraulic system, and each has a pressure sensor installed inside.

[0042] During the operation of engineering vehicles, when the driver is loading materials, once the bucket is full, the vehicle no longer needs to move forward but must quickly lift the bucket. In this situation, to achieve more efficient lifting, the boom needs a faster lifting speed. Therefore, the power cut-off function needs to be activated to disconnect the power transmission between the engine and gearbox, putting the gearbox in a disengaged state. At this time, most of the engine torque is transmitted to the working pump, providing greater torque support for the boom and other working devices, thus lifting materials more efficiently.

[0043] Furthermore, in complex operating conditions (such as turning, going uphill, and operating in confined spaces), drivers need to precisely control the vehicle's power output. By precisely controlling the triggering timing of the power cut-off function through a pressure switch, the accidental triggering of the power cut-off function under complex conditions can be avoided, improving operational accuracy and safety.

[0044] In scenarios such as material loading, uphill driving, temporary parking, or leaving the vehicle, the power cut-off function needs to be activated. A power cut-off solenoid valve is installed on the transmission's hydraulic oil line, controlling the flow of hydraulic oil to achieve the power cut-off function. When the power cut-off function is triggered, the solenoid valve is energized, the valve opens, hydraulic oil flows, cutting off the power transmission between the engine and transmission, causing the transmission to lose power assistance and the vehicle to become immobile.

[0045] The power cut-off function switch is usually a manual switch. It controls the on / off state of the power cut-off function by switching the circuit on and off, requiring the driver to manually activate or deactivate the function through a function switch inside the driver's cab. This switch is typically a button or toggle switch, allowing the driver to activate or deactivate the power cut-off function as needed.

[0046] The pressure switch dynamically adjusts based on actual braking pressure, ensuring that the power cut-off function is only triggered when necessary. Installed in the brake pedal's hydraulic system, the pressure switch automatically triggers the power cut-off function by detecting the hydraulic pressure generated by the brake pedal, allowing for more precise control over the timing of the power cut-off. The pressure switch only closes and triggers the power cut-off function when the braking pressure reaches 0.4 MPa. This prevents accidental triggering of the power cut-off during light braking, improving driving safety.

[0047] When engineering vehicles are actually working, the brake pedals of the excavator and loader are divided into left and right sides, which can be used separately or together. When used separately, only one side brakes.

[0048] The following example uses the left brake pedal alone to illustrate its workflow. Figure 1 :

[0049] When engineering vehicles are traveling uphill, drivers need to brake to control speed or stop. When going uphill, if the driver lightly presses the brake pedal, a traditional limit switch may prematurely trigger the power cut-off function, causing the vehicle to lose power and increasing the risk of rolling backward. However, with a pressure switch, the power cut-off function is only triggered when the braking pressure reaches 0.4 MPa, ensuring safe braking when going uphill. Furthermore, when going uphill, the driver only needs to apply sufficient braking pressure to trigger the power cut-off function, without needing to fully depress the brake pedal, making operation much easier.

[0050] When the power cut-off function is activated, the power cut-off function switch is closed, at which point normally open relay 1 closes. Normally open relay 1 is open; when the power cut-off function switch is closed, the control coil of normally open relay 1 is energized, its contacts close, and the power circuit of power cut-off solenoid valve 1 is connected. Power cut-off solenoid valve 1 is now energized, its valve is open, hydraulic oil can flow, and it is ready to execute the power cut-off function, that is, to cut off the power transmission between the engine and the transmission.

[0051] When the driver depresses the left brake pedal, the hydraulic system of the left brake pedal transmits hydraulic oil through the hydraulic oil line to control the operation of the brake. The left brake pedal is connected to a left brake pressure switch, which is installed in a critical position in the hydraulic oil line. It contains a pressure sensor to detect the hydraulic pressure generated when the brake pedal is depressed. When the pressure sensor detects that the pressure in the hydraulic system rises to 0.4 MPa, it triggers the left brake pressure switch to close, connecting the circuit. After the left brake pressure switch is closed, the pressure signal is transmitted to the control unit. The control unit controls the working state of the power cut-off solenoid valve 1 according to the pressure signal. At this time, the power cut-off solenoid valve 1 cuts off the power transmission between the engine and the transmission. The power cut-off solenoid valve 1 is working, and the left indicator light on the instrument panel is illuminated. The left brake power cut-off state can be determined by observing the state of the left indicator light on the instrument panel. If the driver presses the left brake pedal, but the pressure in the hydraulic system does not reach 0.4 MPa, the pressure detected by the pressure sensor inside the left brake pressure switch is insufficient to trigger the left brake pressure switch to close, and the left brake pressure switch remains open. The left brake pressure switch will only close when the pressure reaches or exceeds 0.4 MPa, triggering the power cut-off function. That is, when only the left brake pedal is used, and the detected pressure rises to 0.4 MPa, the left brake power cut-off state is in effect. When the freewheeling diode is used for unidirectional conduction, the signal cannot be transmitted to the right indicator light.

[0052] A parking switch is usually a lever or button. When the driver temporarily stops or leaves the vehicle, the parking switch needs to be pulled up to trigger the power cut-off function to prevent the vehicle from rolling. The parking switch needs to be released before the vehicle can be driven again.

[0053] When the driver pulls the parking switch, the internal mechanical structure or electronic contacts of the switch close, connecting the circuit, and the parking switch closes. The signal is transmitted to the control unit or directly controls the normally open relay 2, triggering the power cut-off function. The control terminal of the normally open relay 2 is energized, the contacts close, and the power cut-off solenoid valve 2 is connected to the power circuit. After the power cut-off solenoid valve 2 is energized, it is triggered to work, the valve opens, hydraulic oil flows, and the power transmission between the engine and the transmission is cut off, ensuring that the vehicle will not move when parked.

[0054] Furthermore, the brake pressure switch can be used in conjunction with a slope sensor to dynamically adjust the triggering conditions of the power cut-off function based on the vehicle's slope and braking pressure, achieving smarter and safer vehicle control, thereby improving driving safety and user experience. For example, when the vehicle is driving uphill, the slope sensor detects the uphill condition, and the electronic control unit (ECU) increases the triggering pressure threshold for the power cut-off function (e.g., from 0.3 MPa to 0.4 MPa). Only when the braking pressure reaches 0.4 MPa will the brake pressure switch close, triggering the power cut-off function to prevent the vehicle from losing power due to slight braking. When the vehicle is driving downhill, the slope sensor detects the downhill condition, and the ECU lowers the triggering pressure threshold for the power cut-off function (e.g., from 0.3 MPa to 0.2 MPa). When the braking pressure reaches 0.2 MPa, the brake pressure switch closes, triggering the power cut-off function to ensure timely vehicle deceleration. When the vehicle is driving on a flat road, the slope sensor detects the flat road condition, and the ECU executes the power cut-off function according to the default triggering conditions (e.g., 0.4 MPa).

[0055] This invention uses a pressure switch to provide feedback on the actual braking pressure state, thereby triggering the power cut-off function. When braking is required while driving uphill, the power cut-off function will not be triggered due to the first half of the pedal travel. Power cut-off is performed when the pressure rises to 0.4 MPa. At this time, the mechanical brake has reached the second half of its travel, and together with the power cut-off, the entire vehicle is controlled.

[0056] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A loader power cut-off system characterized by, It comprises: A first brake pressure switch unit, which is connected with a one-way diode and a first power cut-off electromagnetic valve in sequence, and the first power cut-off electromagnetic valve is installed in the hydraulic oil pipeline on the gearbox; The first brake pressure switch unit comprises a first brake pressure switch and a control unit, the first brake pressure switch is installed in the hydraulic system of the brake pedal, and is used for detecting the hydraulic pressure borne by the brake pedal when it is stepped on and transmitting to the control unit; The control unit is electrically connected with the first power cut-off electromagnetic valve.

2. A power shutdown system for a loader as set forth in claim 1, characterized in that The first end of the first brake pressure switch unit is grounded, the second end of the first brake pressure switch unit is connected with the positive electrode of the one-way diode, and the negative electrode of the one-way diode is connected with the first end of the first power cut-off electromagnetic valve.

3. A power shutdown system for a loader as set forth in claim 2, wherein The second end of the first power cut-off electromagnetic valve is connected with a first normally open relay and a power cut-off function switch in sequence, and the power cut-off function switch opens and closes the power cut-off function by controlling the on-off of the control circuit.

4. A power shutdown system for a loader as set forth in claim 1, wherein, A first instrument indicating lamp is connected between the first brake pressure switch unit and the one-way diode.

5. A power take-off system for a loader as set forth in claim 1, wherein It further comprises: A second brake pressure switch unit, which is connected with a one-way diode and a first power cut-off electromagnetic valve in sequence, and the first power cut-off electromagnetic valve is installed in the hydraulic oil pipeline on the gearbox; The second brake pressure switch unit comprises a second brake pressure switch and a control unit, the second brake pressure switch is installed in the hydraulic system of the brake pedal, and is used for detecting the hydraulic pressure borne by the brake pedal when it is stepped on and transmitting to the control unit; The control unit is electrically connected with the first power cut-off electromagnetic valve.

6. A power takeoff system for a loader as set forth in claim 5, wherein The second brake pressure switch unit is connected in parallel with the first brake pressure switch unit.

7. A power takeoff system for a loader as set forth in claim 5, wherein The first end of the second brake pressure switch unit is grounded, the second end of the second brake pressure switch unit is connected with the positive electrode of the one-way diode, and the negative electrode of the one-way diode is connected with the first end of the first power cut-off electromagnetic valve.

8. A power takeoff system for a loader as set forth in claim 5, wherein A second instrument indicating lamp is connected between the second brake pressure switch unit and the one-way diode.

9. A power takeoff system for a loader as set forth in claim 1, wherein It further comprises: A parking switch, which is connected with an instrument parking indicating lamp, a second normally open relay and a second power cut-off electromagnetic valve in sequence, and the second power cut-off electromagnetic valve is installed in the hydraulic oil pipeline on the gearbox; the parking switch transmits an electric signal to the control unit or directly controls the second normally open relay.

10. A power takeoff system for a loader as set forth in either of claims 1 or 5, wherein The first brake pressure switch and the second brake pressure switch are both installed in the hydraulic oil pipeline of the hydraulic system and internally provided with a pressure sensor.

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