Parking brake hydraulic control system with buffer braking function

Abstract

The utility model discloses a parking brake hydraulic control system with buffer brake function, including brake oil supply unit, the oil outlet of brake oil supply unit is linked with the oil inlet of control valve block, the oil outlet of control valve block is linked with parking brake, and control valve block includes two position three way electromagnetic valve, and the oil outlet of two position three way electromagnetic valve is provided with pressure reducing valve and check valve, and the oil outlet of pressure reducing valve is provided with damping plug, and the oil outlet between damping plug and control valve block is provided with buffer energy accumulator. The utility model discloses simple structure, through setting damping plug and buffer energy accumulator in parking brake valve block inside, through the buffer effect of damping plug and buffer energy accumulator, when the vehicle parking, make the pressure of parking brake release gradually reduce, and the vehicle deceleration is smaller, and the goods of emergency vehicle emergency stop caused will not appear the accident of inertia throwing, and the cost increases very little, and the scheme change is smaller, and the user with such demand carries out vehicle modification.

Description

Technical Field

[0001] This utility model relates to the field of forklift technology, specifically a parking brake hydraulic control system with buffer braking function. Background Technology

[0002] Small forklifts typically use mechanical parking brakes. When the vehicle stops, the handbrake device pulls a cable, which in turn pulls the parking brake lever, causing the parking brake pads to press together to achieve parking. However, larger forklifts (5-10 tons) use hydraulic negative parking brakes on some high-end models to improve parking brake reliability and reduce operational intensity. In the absence of high-pressure oil, the parking brake pads are held in place by a spring. When the vehicle is moving, pressurized oil is supplied to the piston chamber of the brake, overcoming the spring force and releasing the brake pads, thus disengaging the parking brake. Generally, an electromagnetic valve controls the supply of pressurized oil to the negative brake, enabling electronic control of the parking brake. When the solenoid valve is de-energized, pressurized oil does not flow to the parking brake, and parking is effective; when the solenoid valve is energized, pressurized oil flows to the parking brake, releasing it.

[0003] The action of the parking brake release solenoid valve is generally controlled by the vehicle controller. Combined with the parking brake button switch status and the vehicle status, it can realize safety functions such as automatic parking. However, this also leads to a problem: when the vehicle's electrical system malfunctions and causes a power outage, the solenoid valve loses power, causing the vehicle to immediately enter the parking brake state. If the vehicle is in motion at this time, it will brake suddenly. If the forklift is carrying goods at this time, the goods may be thrown off the forks due to inertia, potentially causing damage. To address this, a parking brake hydraulic control system with a buffer braking function is proposed. Utility Model Content

[0004] The purpose of this invention is to provide a parking brake hydraulic control system with a buffer braking function to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a parking brake hydraulic control system with buffer braking function, including a brake oil supply unit, wherein the oil outlet of the brake oil supply unit is connected to the oil inlet of a control valve block, the oil outlet of the control valve block is connected to the parking brake, the control valve block includes a two-position three-way solenoid valve, the oil outlet of the two-position three-way solenoid valve is provided with a pressure reducing valve and a check valve, a damping plug is provided at the oil outlet of the pressure reducing valve, and a buffer accumulator is provided between the damping plug and the oil outlet of the control valve block.

[0006] As a further embodiment of this utility model: the two-position three-way solenoid valve has an oil inlet, an oil outlet, and an oil drain. The oil inlet of the two-position three-way solenoid valve is connected to the oil inlet of the control valve block, the oil outlet of the two-position three-way solenoid valve is connected to the pressure reducing valve, and the oil drain of the two-position three-way solenoid valve is connected to the oil tank.

[0007] As a further embodiment of this utility model: the control valve block further includes a first pressure detection switch disposed between the oil inlet of the two-position three-way solenoid valve and the oil outlet of the brake oil supply unit.

[0008] As a further embodiment of this utility model: the damping plug is provided with a through hole, the diameter of which is 0.5-1.5mm.

[0009] As a further aspect of this utility model: the volume of the buffer accumulator is 0.16L and its pre-charge pressure is 10bar.

[0010] As a further embodiment of this utility model: a second pressure detection switch is provided between the damping plug and the oil outlet of the control valve block.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] This application incorporates a damping plug and a buffer accumulator inside the parking brake valve block. Through the buffering effect of the damping plug and the buffer accumulator, the pressure for releasing the parking brake is gradually reduced when the vehicle is parked, resulting in a smaller vehicle deceleration. This prevents accidents caused by cargo being thrown out due to inertia during sudden vehicle stops in emergency situations. At the same time, the cost increase is minimal, and the solution requires minimal modification, making it convenient for users with such needs to modify their vehicles. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the parking brake hydraulic control system of this utility model;

[0014] Figure 2 This is a schematic diagram of the prior art for the parking brake hydraulic control system of this utility model;

[0015] Figure 3 This is a schematic diagram showing the pressure change comparison curve of the parking brake chamber of this utility model.

[0016] In the diagram: 1. Brake oil supply unit; 2. Control valve block; 21. Two-position three-way solenoid valve; 22. Pressure reducing valve; 23. Check valve; 24. First pressure detection switch; 25. Second pressure detection switch; 26. Damping plug; 3. Oil tank; 4. Buffer accumulator; 5. Parking brake. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Please see Figure 1-3 In this embodiment of the utility model, the parking brake hydraulic control system with buffer braking function includes a brake oil supply unit 1. The oil outlet of the brake oil supply unit 1 is connected to the oil inlet of the control valve block 2. The oil outlet of the control valve block 2 is connected to the parking brake 5. The control valve block 2 includes a two-position three-way solenoid valve 21. The oil outlet of the two-position three-way solenoid valve 21 is provided with a pressure reducing valve 22 and a one-way valve 23. A damping plug 26 is provided at the oil outlet of the pressure reducing valve 22. A through hole is opened on the damping plug 26. The diameter of the through hole is 0.5-1.5mm. A buffer accumulator 4 is provided between the damping plug 26 and the oil outlet of the control valve block 2. Taking a 10-ton electric forklift as an example, the parking release pressure is 55 bar, the required oil volume for parking release is 36 mL, the diameter of the through hole is 1.5 mm, the volume of the buffer accumulator 4 is 0.16 L, and its pre-charge pressure is 10 bar.

[0019] Specifically, the brake oil supply unit 1 is connected to a two-position three-way solenoid valve 21 via a pipeline. The two-position three-way solenoid valve 21 is connected to the electronic control unit (not shown in the figure). The two-position three-way solenoid valve 21 is connected to a pressure reducing valve 22 and a one-way valve 23 via pipelines. Both the pressure reducing valve 22 and the one-way valve 23 are connected to a damping plug 26 via pipelines. The damping plug 26 is connected to a buffer accumulator 4 and a parking brake 5 via pipelines to ensure that the pressurized oil in the brake oil supply unit 1 can enter the parking brake 5, overcome the spring force in the parking brake 5, release the brake friction pads, and thus release the parking brake.

[0020] The pressurized oil first enters the two-position three-way solenoid valve 21 from the brake oil supply unit 1, then enters the pressure reducing valve 22 through the two-position three-way solenoid valve 21, and then enters the buffer accumulator 4 and the parking brake 5 through the damping plug 26. This causes the pressure in the piston chambers of the buffer accumulator 4 and the parking brake 5 to gradually increase, pushing the parking piston to overcome the spring force and gradually release the parking friction pads to release the parking brake. When the parking brake is fully released, the vehicle can move.

[0021] When the vehicle malfunctions and loses power, all the pressurized oil in the parking brake 5 and the buffer accumulator 4 enters the one-way valve 23 through the damping plug 26, and then enters the two-position three-way solenoid valve 21 through the one-way valve 23 and finally returns to the oil tank 3. During this process, since the pressurized oil in the buffer accumulator 4 and the piston chamber must pass through the damping plug 26, the pressure in the piston chamber of the parking brake 5 will not immediately drop to 0, but will gradually decrease. As a result, the torque of the parking brake will also gradually increase. Therefore, in an emergency, when the vehicle is parked at a certain speed, the vehicle will not immediately stop, causing the cargo on the forks to be thrown out due to inertia.

[0022] Through the above technical solution, a damping plug 26 and a buffer accumulator 4 are added to the control valve block 2. After the parking solenoid valve is de-energized, the pressure in the parking brake chamber gradually decreases, which can solve the problem of "sudden braking" caused by the parking brake taking effect immediately when the vehicle speed is not zero to a certain extent, thereby preventing the goods on the forks from falling off due to sudden braking.

[0023] Please see Figure 1 In one embodiment, preferably, the two-position three-way solenoid valve 21 has an inlet, an outlet, and a drain port. The inlet of the two-position three-way solenoid valve 21 is connected to the inlet of the control valve block 2, the outlet of the two-position three-way solenoid valve 21 is connected to the pressure reducing valve 22, and the drain port of the two-position three-way solenoid valve 21 is connected to the oil tank 3. Further, the inlet of the two-position three-way solenoid valve 21 only allows pressure oil from the brake oil supply unit 1 to enter. When the parking brake is released, pressure oil is output from the outlet; while when the parking brake is applied, the outlet is used for oil intake. At the same time, during the parking brake process, the drain port discharges the pressure oil in the two-position three-way solenoid valve 21 into the oil tank 3.

[0024] Please see Figure 1 In one embodiment, preferably, the control valve block 2 further includes a first pressure detection switch 24 disposed between the oil inlet of the two-position three-way solenoid valve 21 and the oil outlet of the brake oil supply unit 1, which is further used to detect whether the working pressure of the brake oil supply unit 1 is normal.

[0025] Please see Figure 1 In one embodiment, preferably, a second pressure detection switch 25 is provided between the damping plug 26 and the oil outlet of the control valve block 2. Further, the second pressure detection switch 25 detects whether the pressure entering the parking brake 5 reaches the minimum pressure for parking release. During this process, when the pressure reaches the preset monitoring pressure, it indicates that the parking brake is fully released. After receiving the signal, the electronic control unit controls the travel motor to work, and the vehicle travels. If the pressure does not reach the preset pressure value within a specified time, that is, the switch does not act within the specified time, it indicates that the system is malfunctioning and the parking brake is not fully released. In this case, the electronic control unit issues an alarm signal.

[0026] The working principle and usage process of this utility model: The brake oil supply unit 1 provides a pressurized oil source. When the vehicle needs to move, the electronic control unit controls the two-position three-way solenoid valve 21 to be energized. The pressurized oil passes through the two-position three-way solenoid valve 21 and the pressure reducing valve 22, reducing the pressure to the pressure required to release the parking brake. It then enters the buffer accumulator 4 and the parking brake 5 through the through hole on the damping plug 26. The pressure in the piston chambers of the buffer accumulator 4 and the parking brake 5 gradually increases, pushing the parking piston to overcome the spring force and gradually releasing the parking friction plate to release the parking brake. When the parking brake is fully released, the vehicle can move. During this process, the second pressure detection switch 25 detects whether the pressure entering the parking brake 5 has reached the minimum pressure for parking to be released. When the pressure reaches the preset monitoring pressure, it indicates that the parking brake has been fully released. After receiving the signal, the electronic control unit controls the travel motor to work and the vehicle moves. If the pressure does not reach the preset pressure value within the specified time, that is, the switch does not act within the specified time, it indicates that the system is malfunctioning and the parking brake has not been fully released. In this case, the electronic control unit issues an alarm signal (the connection between the electronic control unit, the travel motor, and other units is existing technology and will not be described in detail here).

[0027] When the vehicle needs to be parked, the electronic control unit controls the two-position three-way solenoid valve 21 to be de-energized. Or, in an emergency, the vehicle loses power, causing the two-position three-way solenoid valve 21 to be de-energized. All the pressurized oil in the piston chamber of the parking brake 5 and the pressurized oil in the buffer accumulator 4 returns to the oil tank 3 through the through hole on the damping plug 26, the one-way valve 23, and the two-position three-way solenoid valve 21. Because the pressurized oil in the buffer accumulator 4 and the piston chamber of the parking brake 5 both need to pass through the through hole on the damping plug 26, the pressure in the piston chamber of the parking brake 5 will not immediately drop to 0, but will gradually decrease. As a result, the parking brake torque will also gradually increase. Therefore, in an emergency, when the vehicle is parked at a certain speed, the vehicle will not immediately stop, causing the cargo on the forks to be thrown out due to inertia.

[0028] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0029] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A parking brake hydraulic control system with a buffer braking function, comprising a brake oil supply unit, wherein the oil outlet of the brake oil supply unit is connected to the oil inlet of a control valve block, and the oil outlet of the control valve block is connected to a parking brake, characterized in that, The control valve block includes a two-position three-way solenoid valve. The oil outlet of the two-position three-way solenoid valve is equipped with a pressure reducing valve and a check valve. A damping plug is provided at the oil outlet of the pressure reducing valve. A buffer accumulator is provided between the damping plug and the oil outlet of the control valve block.

2. The parking brake hydraulic control system with buffer braking function according to claim 1, characterized in that, The two-position three-way solenoid valve has an oil inlet, an oil outlet, and an oil drain. The oil inlet of the two-position three-way solenoid valve is connected to the oil inlet of the control valve block, the oil outlet of the two-position three-way solenoid valve is connected to the pressure reducing valve, and the oil drain of the two-position three-way solenoid valve is connected to the oil tank.

3. The parking brake hydraulic control system with buffer braking function according to claim 2, characterized in that, Furthermore, the control valve block also includes a first pressure detection switch disposed between the oil inlet of the two-position three-way solenoid valve and the oil outlet of the brake oil supply unit.

4. The parking brake hydraulic control system with buffer braking function according to claim 1, characterized in that, The damping plug has a through hole with a diameter of 0.5-1.5 mm.

5. The parking brake hydraulic control system with buffer braking function according to claim 1, characterized in that, The buffer accumulator has a volume of 0.16L and a pre-charge pressure of 10 bar.

6. The parking brake hydraulic control system with buffer braking function according to claim 1, characterized in that, A second pressure detection switch is provided between the damping plug and the oil outlet of the control valve block.

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