Off-highway dump truck auxiliary braking system

Abstract

The utility model discloses a kind of off-highway dump truck auxiliary braking systems, belong to off-highway dump truck braking technical field, including the hydraulic clamp disc type auxiliary brake of being installed in middle axle and rear axle transmission shaft, and the hydraulic control unit consisting of hydraulic power unit, auxiliary brake valve, energy accumulator and connecting pipeline;Hydraulic power unit connects steering hydraulic oil tank and auxiliary brake valve, and energy accumulator supplies high-pressure oil to auxiliary brake valve to auxiliary brake to release brake.The system is mainly used to improve off-highway dump truck parking brake safety and braking force, applicable to the vehicle of design load 90 tons below, provide redundancy brake guarantee for off-highway dump truck, realize quick response auxiliary brake when main brake fails.

Description

Technical Field

[0001] This utility model relates to the field of braking technology for off-highway dump trucks. More specifically, this utility model relates to an auxiliary braking system for off-highway dump trucks. Background Technology

[0002] Off-highway dump trucks are crucial transportation equipment in open-pit mines, hydropower projects, and large-scale engineering operations, and the reliability of their braking systems directly impacts operational safety. Currently, off-highway dump trucks with a design load capacity of 90 tons or less generally employ pneumatic drum braking systems. While these systems offer advantages such as high braking torque, simple structure, and convenient maintenance, they also have significant drawbacks: First, pneumatic drum brakes have poor heat dissipation performance. During continuous braking, heat accumulation can cause a sharp decrease in the friction coefficient between the brake shoes and the drum surface, resulting in severe thermal fade and potentially even brake failure. Second, braking force stability is insufficient, with significant differences in braking performance under different road conditions. Drivers find it difficult to precisely control the braking force, especially on wet or muddy surfaces, where braking distances can be significantly extended.

[0003] With the application of electric drive technology in off-highway dump trucks, motor-assisted braking technology improves energy efficiency by converting kinetic energy into electrical energy for deceleration. However, when vehicles are heavily loaded and descending slopes, continuous use of motor-assisted braking can lead to overcharging of the high-voltage battery pack. This causes a significant decrease or even failure of the assist braking capability, necessitating reliance on the mechanical braking of the axle. However, under heavy-load continuous braking conditions, traditional pneumatic drum brakes exhibit more pronounced overheating problems, resulting in a sharp decrease in braking torque and seriously threatening driving safety. Therefore, there is an urgent need for an auxiliary braking solution independent of the main braking system that can provide stronger parking braking force, capable of timely braking in the event of such dangerous situations to ensure the safety of personnel and property. Utility Model Content

[0004] This utility model provides an auxiliary braking system for off-highway dump trucks, which can improve the parking brake safety and braking force of off-highway dump trucks. It is suitable for vehicles with a design load of less than 90 tons, provides redundant braking protection for off-highway dump trucks, and achieves rapid response auxiliary braking when the main brake fails.

[0005] To achieve these objectives and other advantages according to this utility model, an auxiliary braking system for off-highway dump trucks is provided, which is connected in parallel with the original vehicle parking brake system to jointly provide parking braking force, including:

[0006] A set of auxiliary brakes, which are respectively installed on the middle axle drive shaft and the rear axle drive shaft, wherein the auxiliary brakes are hydraulic caliper disc brakes;

[0007] The hydraulic control unit includes a hydraulic power unit, an auxiliary brake valve, an accumulator, and connecting pipelines. The input end of the hydraulic power unit is connected to the steering hydraulic oil tank, and the output end is connected to the oil inlet of the auxiliary brake valve. The first oil outlet of the auxiliary brake valve is connected to the accumulator, and the second oil outlet is connected to the auxiliary brake. The accumulator supplies high-pressure oil to the auxiliary brake through the auxiliary brake valve to release the brake.

[0008] Preferably, the auxiliary braking valve has a built-in electromagnetic reversing valve. When the electromagnetic coil is de-energized, it cuts off the oil circuit from the accumulator to the auxiliary brake, so that the auxiliary brake is in a braking state. When the electromagnetic coil is energized, it opens the oil circuit from the accumulator to the auxiliary brake, so that the auxiliary brake is released from the braking state.

[0009] Preferably, the auxiliary brake valve integrates a manual reversing mechanism, which allows for manual reversing of the oil circuit when the electromagnetic coil fails.

[0010] Preferably, the auxiliary brake valve has a built-in relief valve that releases overpressure fluid into the steering hydraulic oil tank.

[0011] Preferably, it also includes:

[0012] The manual pump has its input end connected to the steering hydraulic oil tank and its output end connected to the bypass port of the auxiliary brake valve via a quick connector.

[0013] Preferably, it also includes a pressure detection unit, which includes:

[0014] The first pressure sensor detects the oil pressure of the auxiliary brake and stores it in the vehicle's onboard recorder;

[0015] The second pressure sensor detects the oil pressure in the accumulator and is connected to the VCU controller signal.

[0016] The pressure switch detects the working status of the auxiliary brake and outputs an on / off signal to the instrument indicator light.

[0017] Preferably, it also includes:

[0018] A manual ball valve, installed in the return line of the auxiliary brake valve, releases residual pressure oil in the system to the steering hydraulic oil tank.

[0019] Preferably, the design load range for off-highway dump trucks is below 90 tons.

[0020] This utility model has at least the following beneficial effects:

[0021] First, the auxiliary braking system of this utility model is connected in parallel with the original vehicle parking braking system, independent of the main braking system, and controlled by the hydraulic system. It can be quickly activated when the main brake fades or fails, solving the problem of heat fade of existing pneumatic drum brakes and providing higher parking braking force for the whole vehicle.

[0022] Secondly, this utility model sets independent hydraulic caliper disc auxiliary brakes on the middle and rear axle drive shafts. The hydraulic control unit uses an accumulator to store high-pressure oil to ensure stable pressure when the brake is released. The system is independent of the main brake to avoid mutual interference. It has fewer components, higher reliability, and faster auxiliary braking response, effectively improving the safety of the vehicle when going downhill under heavy load and when parking.

[0023] Third, this utility model limits the design load range to below 90 tons, so that the braking torque of the auxiliary braking system is precisely matched with the vehicle load, avoiding the problems of insufficient braking force or overload. Within this load range, the system can provide sufficient parking braking force and play an emergency braking role when the main brake fails, ensuring braking safety and reliability under different loads.

[0024] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0025] Figure 1 This is a structural schematic diagram of one technical solution of this utility model. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0027] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0028] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials described are commercially available. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] Existing main braking systems suffer from insufficient braking force due to heat fade during heavy-load downhill driving. This invention provides an auxiliary braking system for off-highway dump trucks, which is connected in parallel with the original parking brake system to jointly provide parking braking force. Figure 1 As shown, it includes:

[0030] A set of auxiliary brakes 7 are respectively installed on the middle axle drive shaft and the rear axle drive shaft. That is, an auxiliary brake 7 and a brake disc are added to the drive shafts of the middle axle and the rear axle respectively. When the service brake fails, the auxiliary braking system can be activated immediately. The auxiliary brake 7 is a hydraulic caliper disc brake. The brake disc is rigidly connected to the drive shaft by high-strength bolts. The brake caliper is hydraulically driven to clamp the brake disc to generate friction force. It has a pressure loss protection function. When there is no high-pressure oil, the brake piston extends under the action of its internal disc spring and presses the friction pads onto the brake disc. The brake disc and the drive shaft are connected by high-strength bolts to form a rigid body. The friction force generated by the brake friction pads and the brake disc is converted into braking force on the wheels, thereby realizing the auxiliary braking function.

[0031] The hydraulic control unit includes a hydraulic power unit 3, an auxiliary brake valve 5, an accumulator 6, and connecting pipelines. It generates, controls, and stores high-pressure oil to achieve braking and releasing of the auxiliary brake 7. The hydraulic power unit 3 is a gear pump driven by a DC motor. The input end of the hydraulic power unit 3 is connected to the steering hydraulic oil tank 1, and the output end is connected to the oil inlet P port of the auxiliary brake valve 5. Oil is supplied to the accumulator 6 through a one-way valve 5.1. The first oil outlet AC port of the auxiliary brake valve 5 is connected to the accumulator 6, and the second oil outlets A1 and A2 are connected to the auxiliary brake 7. The accumulator 6 is used to store high-pressure oil, which can effectively ensure that the pressure is continuous and stable when the auxiliary brake is released. The hydraulic power unit 3 stops after reaching the set value and restarts after falling below the set value, which can effectively reduce the power consumption. The accumulator 6 supplies high-pressure oil to the auxiliary brake 7 through the auxiliary brake valve 5 to release the brake. When the auxiliary brake valve 5 is open, the high-pressure oil enters the auxiliary brake 7, pushes the piston to retract, and releases the brake. When the auxiliary brake valve 5 cuts off the oil circuit, there is no high-pressure oil in the auxiliary brake 7, the piston extends under the action of the disc spring, and the friction pad presses the brake disc to achieve braking.

[0032] After the hydraulic power unit 3 starts, the gear pump draws oil from the steering hydraulic oil tank 1 and outputs high-pressure oil to the auxiliary brake valve 5, which then charges the accumulator 6 via the check valve 5.1. When the pressure in the accumulator 6 reaches the set value, the hydraulic power unit 3 stops; it restarts when the pressure is lower than the set value. During normal vehicle operation, the solenoid directional valve of the auxiliary brake valve 5 is energized, and the high-pressure oil in the accumulator 6 enters the auxiliary brake 7, overcoming the disc spring force to push the piston back, separating the friction pads from the brake disc, and releasing the brake from the auxiliary brake 7. When auxiliary braking is needed (such as when the main brake fails or when parking), the solenoid directional valve is de-energized, the oil circuit is cut off, and the auxiliary brake 7 clamps the brake disc under the action of the disc spring, generating braking torque, which is connected in parallel with the original vehicle parking brake system to provide parking braking force.

[0033] Specifically, such as Figure 1As shown, port P of auxiliary brake valve 5 is the power unit oil inlet, through which high-pressure oil output from the power unit enters the system; port P1 is the manual pump oil inlet, through which high-pressure oil output from the manual pump enters the system when the power unit fails; port L is the manual drain port, used to quickly release residual high-pressure oil in the system during maintenance; port M is the accumulator pressure sensor port, monitoring the real-time pressure in the accumulator. When the pressure is lower than the set value, the power unit automatically starts; when the pressure reaches the set value, the power unit automatically stops; port AC is the accumulator oil port, through which high-pressure oil is stored, maintaining a constant pressure even when the power unit is turned off. The auxiliary brake remains in the released state; Port A1 is the oil outlet of the middle axle auxiliary brake, where high-pressure oil is output to the middle axle auxiliary brake to release it; Port A2 is the oil outlet of the rear axle auxiliary brake, where high-pressure oil is output to the rear axle auxiliary brake to release it; Port M1 is the pressure switch oil port, where the instrument auxiliary brake light illuminates when the pressure is below the set value and extinguishes when the pressure is above the set value, participating in logic control, and prohibiting driving when the auxiliary brake is not released; Port M2 is the auxiliary brake release pressure sensor port, monitoring the auxiliary brake release pressure; Port T is the return oil port, used for system oil return.

[0034] In the above technical solution, by installing independent hydraulic caliper disc auxiliary brakes 7 on the middle and rear axle drive shafts, which work in parallel with the original vehicle parking brake system, they can be activated immediately when the main braking system experiences heat fade or failure, providing additional braking torque. The hydraulic control unit uses an accumulator 6 to store high-pressure oil, ensuring stable pressure when the brake is released, and the system is independent of the main brake to avoid mutual interference, effectively improving the vehicle's safety when going downhill under heavy load and when parking.

[0035] To address the issue of automated control of the auxiliary braking system and achieve precise switching of braking states, in another technical solution, the auxiliary braking valve 5 incorporates a built-in electromagnetic directional valve 5.2, whose electromagnetic coil is connected to the vehicle's EPB system. By controlling the on / off state of the electromagnetic coil, the oil circuit is opened and closed, thereby achieving automatic switching of the auxiliary brake 7. The general name for the EPB system is Electronic Parking Brake. When the driver operates the EPB system or the vehicle is turned off, the auxiliary brake 7 automatically brakes to prevent the vehicle from rolling backwards. Specifically, the solenoid coil is de-energized, cutting off the oil circuit from the accumulator 6 to the auxiliary brake 7. With no high-pressure oil in the auxiliary brake 7, the disc spring pushes the piston out, and the friction pads press against the brake disc, keeping the auxiliary brake 7 in a braking state and preventing driving. When the vehicle is started and geared, the high-pressure oil releases the auxiliary brake 7, allowing the vehicle to move. Specifically, the solenoid coil is energized, and the electromagnetic force pushes the valve core to move, opening the oil circuit from the accumulator 6 to the auxiliary brake 7. High-pressure oil enters the auxiliary brake 7, pushing the piston back, separating the friction pads from the brake disc, thus releasing the auxiliary brake 7 from its braking state. No braking force is generated, allowing driving, thus meeting the real-time control needs of the auxiliary brake during vehicle operation.

[0036] To improve the emergency reliability of the system and solve the problem of the auxiliary braking system failing to function properly when the electromagnetic coil fails, in another technical solution, the auxiliary brake valve 5 integrates a manual reversing mechanism. The manual operating component set on the electromagnetic reversing valve 5.2 is usually a knob or lever structure mechanically connected to the valve core. As a redundant design of the electromagnetic reversing valve 5.2, when the electromagnetic coil fails, the valve core position is forcibly switched manually to realize the oil circuit reversal, ensuring that the auxiliary brake 7 can be released normally. This avoids the situation where the vehicle cannot move due to low-voltage control electrical faults or electromagnetic coil failures. Even if the electromagnetic reversing valve 5.2 of the auxiliary brake valve 5 cannot be reversed, the auxiliary brake can still be released through the manual function, thus improving the reliability and emergency response capability of the system.

[0037] To ensure the safe operation of the hydraulic system when the system pressure is too high and to prevent damage to the hydraulic power unit 3 and auxiliary brake 7, in another technical solution, the auxiliary brake valve 5 has a built-in relief valve 5.3 that monitors the system pressure in real time. The opening pressure of the relief valve 5.3 is set to the upper limit of the system's safe pressure. When the pressure exceeds the safe threshold, it automatically opens, releasing the overpressure oil to the steering hydraulic oil tank 1. When the pressure drops below the set value, the relief valve 5.3 closes, restoring normal oil supply. This prevents high pressure from damaging components such as the hydraulic power unit 3 and auxiliary brake 7, limits the system pressure within a safe range, extends the system's service life, and ensures the safe operation of the hydraulic system.

[0038] To ensure that the auxiliary braking system can still release the brakes normally when the power source fails, another technical solution also includes: a manual pump 2, whose input end is connected to the steering hydraulic oil tank 1 and whose output end is connected to the bypass port P1 of the auxiliary brake valve 5 through a quick connector 4. It is used to provide high-pressure oil when the power source fails, as an emergency oil source. When the hydraulic power unit 3 fails and cannot output high-pressure oil, high-pressure oil can be output to the system through the manual pump 2 to release the auxiliary brake 7, ensuring that the vehicle can still move to a safe area when the power source fails, and avoiding rescue difficulties caused by the inability to release the brakes.

[0039] To monitor system pressure and braking status in real time, another technical solution also includes a pressure detection unit, which comprises:

[0040] The first pressure sensor 8.1 detects the oil pressure of the auxiliary brake 7, records the pressure at the brake actuator end, and stores it in the vehicle recorder to provide data support for system fault analysis and maintenance.

[0041] The second pressure sensor 8.2 detects the oil pressure of the accumulator 6 and is connected to the VCU controller. The VCU, or Vehicle Control Unit, monitors the pressure of the accumulator 6 and feeds it back to the VCU controller to enable the automatic start and stop of the power unit to maintain pressure stability. When the pressure is lower than the set lower limit, the VCU controller sends a command to start the hydraulic power unit 3 to charge the accumulator 6 with oil. When the pressure reaches the set upper limit, the VCU controller commands the hydraulic power unit 3 to stop, thus achieving automatic maintenance of the pressure of the accumulator 6.

[0042] Pressure switch 9 detects the working status of auxiliary brake 7, provides real-time feedback on braking status, and outputs on / off signals to the instrument indicator lights to control the indicator lights to light up or turn off, thus visually displaying the auxiliary braking status.

[0043] In the above technical solution, the pressure detection unit is used to monitor the working status of the auxiliary braking in real time, and can also participate in the logic control to realize the automation of the auxiliary braking. The setting of the first pressure sensor 8.1 and the pressure switch 9 facilitates the driver to monitor the working status of the system, provides data support for fault diagnosis, facilitates timely detection and handling of system abnormalities, and improves the intelligence and safety of the system.

[0044] To reduce high-pressure oil leakage and contamination during maintenance and to lower safety risks, another technical solution also includes:

[0045] A manual ball valve 10, installed in the return line of the auxiliary brake valve 5, releases residual pressure oil from the system to the steering hydraulic oil tank 1. When maintenance or component replacement of the auxiliary braking system is required, the vehicle power is turned off, and the ball valve is opened to quickly release residual high-pressure oil in the system. The oil flows back to the steering hydraulic oil tank 1 through the return line and manual ball valve 10, reducing the system pressure to zero. After maintenance is completed, the manual ball valve 10 is closed to restore the normal oil circuit of the system, preventing hydraulic oil leakage and contamination, eliminating the safety threat of high-pressure oil to maintenance personnel, simplifying the maintenance process, and improving maintenance safety.

[0046] To address the compatibility issue of auxiliary braking systems on vehicles with varying load capacities and ensure that braking force matches vehicle load, another technical solution is proposed. This solution specifies that the off-highway dump truck has a design load capacity of less than 90 tons, defined as the maximum load weight specified in the vehicle's design. Based on this design load capacity, the braking torque of the auxiliary braking system is matched to the vehicle load. Specifically, the disc spring force and hydraulic system pressure of the auxiliary brake 7 ensure sufficient friction between the friction pads and the brake disc, guaranteeing that the auxiliary brake 7 provides adequate parking and emergency braking force within this load range. When connected in parallel with the original parking brake system, they jointly provide the braking torque required for parking, avoiding insufficient braking effect or component overload due to load mismatch.

[0047] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of this utility model will be readily apparent to those skilled in the art.

[0048] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. An auxiliary braking system for off-highway dump trucks, which is connected in parallel with the original vehicle parking braking system to jointly provide parking braking force, characterized in that, include: A set of auxiliary brakes, which are respectively installed on the middle axle drive shaft and the rear axle drive shaft, wherein the auxiliary brakes are hydraulic caliper disc brakes; The hydraulic control unit includes a hydraulic power unit, an auxiliary brake valve, an accumulator, and connecting pipelines. The input end of the hydraulic power unit is connected to the steering hydraulic oil tank, and the output end is connected to the oil inlet of the auxiliary brake valve. The first oil outlet of the auxiliary brake valve is connected to the accumulator, and the second oil outlet is connected to the auxiliary brake. The accumulator supplies high-pressure oil to the auxiliary brake through the auxiliary brake valve to release the brake.

2. The off-highway dump truck auxiliary braking system according to claim 1, characterized in that, The auxiliary braking valve has a built-in electromagnetic reversing valve. When the electromagnetic coil is de-energized, it cuts off the oil circuit from the accumulator to the auxiliary brake, putting the auxiliary brake in a braking state. When the electromagnetic coil is energized, it opens the oil circuit from the accumulator to the auxiliary brake, releasing the auxiliary brake from the braking state.

3. The off-highway dump truck auxiliary braking system according to claim 2, characterized in that, The auxiliary brake valve integrates a manual reversing mechanism, which allows for manual reversing of the oil circuit when the electromagnetic coil fails.

4. The off-highway dump truck auxiliary braking system according to claim 1, characterized in that, The auxiliary brake valve has a built-in relief valve that releases overpressure oil into the steering hydraulic oil tank.

5. The off-highway dump truck auxiliary braking system according to claim 1, characterized in that, Also includes: The manual pump has its input end connected to the steering hydraulic oil tank and its output end connected to the bypass port of the auxiliary brake valve via a quick connector.

6. The off-highway dump truck auxiliary braking system according to claim 1, characterized in that, It also includes a pressure detection unit, which comprises: The first pressure sensor detects the oil pressure of the auxiliary brake and stores it in the vehicle's onboard recorder; The second pressure sensor detects the oil pressure in the accumulator and is connected to the VCU controller signal. The pressure switch detects the working status of the auxiliary brake and outputs an on / off signal to the instrument indicator light.

7. The off-highway dump truck auxiliary braking system according to claim 1, characterized in that, Also includes: A manual ball valve, installed in the return line of the auxiliary brake valve, releases residual pressure oil in the system to the steering hydraulic oil tank.

8. The off-highway dump truck auxiliary braking system according to any one of claims 1-7, characterized in that, The design load range for off-highway dump trucks is below 90 tons.

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