Electric control braking system and engineering machinery

Abstract

The invention relates to an electrically controlled brake system for construction machinery. The electric control braking system comprises a gas storage device (1) used for storing a gas medium; a hydraulic brake (4) for applying a braking force; a brake drive (3) for driving the hydraulic brake (4) with a gaseous medium; the gas medium control unit (2) enables the gas storage device (1) to be connected with the brake driving device (3) so as to control the flow rate of the gas medium applied to the brake driving device (3). According to the invention, the gaseous medium control unit (2) comprises a first control branch and a second control branch which are connected in parallel to one another. The invention further relates to engineering machinery comprising the electric control brake system and a control method of the electric control brake system.

Description

Technical Field

[0001] The present invention relates to an electric control braking system for engineering machinery, in particular to an electric control gas-hydraulic braking system. The present invention also relates to an engineering machinery having such an electric control braking system, in particular to a loader. Background Art

[0002] Construction machinery is widely used in urban construction, mining, water conservancy and electricity and other engineering fields. The brake system of construction machinery is used to slow down and stop the moving construction machinery, to keep the speed of the construction machinery traveling downhill stable, to keep the stationary construction machinery stationary, or to brake the working parts. With the improvement of the performance requirements for construction machinery, the working reliability of the brake system is becoming increasingly important. Only construction machinery with good braking performance and reliable braking system can give full play to its power performance.

[0003] The pneumatic-hydraulic brake system is a commonly used brake system for construction machinery, also known as the "air-over-oil" brake system, in which the compressed air is converted into liquid pressure to generate braking force. Generally, the energy supply device and control device of the pneumatic-hydraulic brake system are pneumatic, while the transmission device is a combination of pneumatic and hydraulic. The pneumatic pressure energy is converted into hydraulic energy through the series-connected power chamber and hydraulic master cylinder, and the hydraulic energy is transmitted to each wheel cylinder to produce a braking effect.

[0004] As the electrification of construction machinery increases, the gas-liquid brake system is increasingly used as an electronically controlled brake system. In this electronically controlled brake system, a proportional valve, especially a proportional solenoid valve, is generally used to control the flow of the gas medium. However, due to the limited diameter of the conventional proportional solenoid valve, when used as an electronically controlled brake valve in the gas-liquid brake system, the build-up and release speed of the brake pressure are both limited by the diameter and difficult to meet the requirements, resulting in the overall braking performance being difficult to meet the requirements. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an electric control braking system and an engineering machine, which can ensure high performance and high efficiency of the braking system at low cost.

[0006] According to a first aspect of the present invention, an electronically controlled braking system is provided, the electronically controlled braking system comprising:

[0007] A gas storage device for storing a gaseous medium;

[0008] hydraulic brakes for applying braking force;

[0009] a brake drive device for driving the hydraulic brake using a gas medium;

[0010] A gas medium control unit, which connects the gas storage device to the brake drive device, thereby controlling the flow rate of the gas medium loaded on the brake drive device;

[0011] The gas medium control unit comprises a first control branch and a second control branch which are connected in parallel with each other.

[0012] According to a second aspect of the present invention, a construction machine comprising the above-mentioned electric control braking system is provided.

[0013] According to a third aspect of the present invention, a method for controlling the above-mentioned electric control braking system is provided, the method comprising the following steps:

[0014] Acquiring an operating signal of a brake operating device;

[0015] determining a brake control signal based on the manipulation signal;

[0016] The first control branch and the second control branch are controlled based on the brake control signal.

[0017] According to the present invention, a first control branch and a second control branch are arranged in parallel in the electric control brake system. Existing components (such as a proportional solenoid valve and a two-position three-way valve) can be used to quickly build up and release the brake pressure. Thus, a high-performance and high-efficiency brake system is realized through a simple and low-cost parallel path solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic principle diagram of an exemplary embodiment of an electronically controlled braking system according to the present invention.

[0019] Figure 2 It is a switching diagram for on / off valves.

[0020] Figure 3 is a flow chart of an exemplary embodiment of a control method for a brake system.

[0021] Reference numerals list

[0022] 1 Gas storage device

[0023] 2 Gas medium control unit

[0024] 3 Brake drive

[0025] 4 Brakes

[0026] 5 Proportional solenoid valve

[0027] 6 First valve

[0028] 61 First port of first valve

[0029] 62 Second port of the first valve

[0030] 63 The third port of the first valve

[0031] 7 Second valve

[0032] 71 First port of the second valve

[0033] 72 Second port of the second valve

[0034] 73 The third port of the second valve

[0035] 8. Pressure sensor DETAILED DESCRIPTION

[0036] The following will describe the electric control brake system and engineering machinery according to the present invention with reference to the accompanying drawings and through specific embodiments. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention comprehensive and complete and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0037] Figure 1 A schematic diagram of an electric control braking system for engineering machinery according to the present invention is shown. Here, an air-liquid electric control braking system is considered as an example, which works with a gas medium, which is generally air. As shown in the figure, the braking system includes a gas storage device 1 for storing a gas medium (generally air). The gas storage device 1 stores compressed air. The gas storage device 1 is connected to a brake drive device 3 via a gas medium control unit 2. Here, the brake drive device 3 can be, for example, a hydraulic mechanism, which converts the energy of the gas medium from the gas medium control unit 2 into hydraulic pressure, and applies the hydraulic pressure to the brake 4, and the brake 4 brakes the wheel or working device of the engineering machinery. The brake drive device 3 includes a booster pump in this example, and / or may also include other types of hydraulic devices, such as hydraulic cylinders, etc. The brake 4 is implemented as a caliper wheel brake, or other types of brakes, for example.

[0038] Here, the gas medium control unit 2 is used to control the flow rate or flow velocity of the gas medium applied to the brake drive 3. Figure 1 As shown, the gas medium control unit 2 includes a first control branch and a second control branch connected in parallel. The first control branch includes a proportional valve, in particular a proportional solenoid valve 5. In the example of the proportional solenoid valve 5, a proportional electromagnet is used as an electrical-mechanical conversion element, which converts an input electrical signal into a mechanical displacement of a valve core, thereby controlling the flow rate of the gas medium flowing through the proportional solenoid valve 5.

[0039] For example, the brake system includes an electronic control unit (not shown), which receives an operating signal from a brake operating device of the brake system, and generates a command signal, such as a pulse width modulation signal, for controlling the proportional solenoid valve 5 based on the operating signal. Generally, the command signal of the electronic control unit is power-amplified by a proportional amplifier, and outputs current proportionally to the proportional solenoid of the proportional valve. The proportional solenoid outputs force and moves the position of the valve core proportionally, so that the flow rate of the gas medium can be proportionally controlled.

[0040] The second control branch includes two two-position three-way valves 6 and 7 connected in series, namely, the first valve 6 and the second valve 7. As shown in the figure, the first interface 61 of the first valve 6 arranged upstream is connected to the gas storage device 1, the third interface 63 leads to the atmosphere, and the second interface 62 is connected to the second interface 72 of the second valve 7 downstream. The first interface 71 of the second valve 7 is connected to the brake drive device 3, and the third interface 73 leads to the atmosphere.

[0041] like Figure 2 As shown, three functional positions can be provided by controlling the first valve 6 and the second valve 7 .

[0042] In the first functional position, the first valve 6 and the second valve 7 are both turned on, wherein the first interface 61 and the second interface 62 of the first valve 6 are in fluid communication, and the third interface 63 is cut off, and the first interface 71 and the second interface 72 of the second valve 7 are in fluid communication, and the third interface 73 is cut off, thereby making the second control branch turned on. In this case, the gas medium can flow from the gas storage device 1 through the first interface 61 and the second interface 62 of the first valve 6 and the second interface 72 and the first interface 71 of the second valve 7 to the brake drive device 3. At this time, additional fluid can be provided, thereby providing additional braking force.

[0043] In the second functional position, the first valve 6 and the second valve 7 are both closed (eg Figure 1 ), wherein the second interface 62 and the third interface 63 of the first valve 6 are in fluid communication, the first interface 61 is cut off, the second interface 72 and the third interface 73 of the second valve 7 are in fluid communication, and the first interface 71 is cut off. In this case, the second control branch is disconnected, so that the gas cannot flow from the gas storage device 1 to the brake actuator 3 through the second control branch, thereby providing a pressure-maintaining function for the brake actuator 3.

[0044] In the third functional position, the first valve 6 is closed and the second valve 7 is turned on, wherein the second port 62 and the third port 63 of the first valve 6 are in fluid communication, the first port 61 is blocked, the first port 71 and the second port 72 of the second valve 7 are in fluid communication, and the third port 73 is blocked. In this case, the brake actuation device 3 is connected to the atmosphere via the first port 71 and the second port 72 of the second valve 7 and the second port 62 and the third port 63 of the first valve 6, thereby providing an exhaust function for the brake actuation device 3.

[0045] The structure of the valve mechanism described above is merely exemplary, and those skilled in the art may conceive of other types of valve mechanisms or other mechanisms based on the present invention, as long as the mechanism can achieve the above three functional positions.

[0046] Preferably, the first valve 6 and the second valve 7 are integrated into a valve block, or the proportional solenoid valve 5, the first valve 6 and the second valve 7 can also be integrated into a common valve block. In addition, a pressure sensor 8 is provided upstream of the brake actuator 3 to detect the pressure of the applied gas medium. In practice, feedback control can be implemented based on the detected pressure of the gas medium.

[0047] The invention also relates to a method for controlling an electronically controlled braking system, the method comprising the following steps:

[0048] Acquiring an operating signal of a brake operating device;

[0049] determining a brake control signal based on the manipulation signal;

[0050] The first control branch and the second control branch are controlled based on the brake control signal.

[0051] In a preferred embodiment, controlling the first control branch and the second control branch based on the brake control signal further includes:

[0052] determining a required brake pressure based on the brake control signal;

[0053] Determine a control signal for controlling the first control branch based on the brake control signal, and operate the first control branch based on the control signal;

[0054] Acquiring an actual brake pressure of the first control branch;

[0055] calculating a difference between a required brake pressure and an actual brake pressure of the first control branch;

[0056] If the absolute value of the difference is not greater than a threshold value (eg, 50 kPa), the second control branch is disconnected so that the gas cannot flow from the gas storage device to the brake actuator through the second control branch.

[0057] If the absolute value of the difference is greater than the threshold value and the difference is positive, the second control branch is turned on, so that the gas medium can flow from the gas storage device to the brake drive device through the second control branch.

[0058] If the absolute value of the difference is greater than a threshold value and the difference is negative, the second control branch causes the brake actuator to be connected to the atmosphere.

[0059] Industrial Applicability

[0060] The following describes how the braking system works. Figure 3 The control method flow chart shown is introduced Figure 1 An exemplary control method of the electronically controlled brake system shown in FIG. 1 is shown. In operation, first, for example, the brake system control unit obtains an operating signal of the brake operating device (S01), and the operating signal may be, for example, the brake pedal displacement. Then, the brake system control unit determines the brake control signal (S02) based on the operating signal. Here, the brake system control unit determines the brake control signal BrkCmd, for example, based on a stored lookup table. Of course, other ways of determining the brake control signal may also be conceivable, such as establishing a calculation model, etc.

[0061] Then, it is determined in S03 whether the brake control signal is greater than 0%. If the brake control signal is not greater than 0%, the first valve 6 is closed and the second valve 7 is opened (S04), and the brake actuator 3 is in a pressure release state.

[0062] If it is determined in S03 that BrkCmd is greater than 0%, this indicates that there is a brake request. Then, in S05, the control signal of the proportional solenoid valve 5 and the corresponding required brake pressure BrkPress_Des (S05) are determined based on the brake control signal. The control signal of the proportional solenoid valve 5 is, for example, a pulse width modulation signal. For example, the control signal of the proportional solenoid valve 5 is determined based on the brake control signal according to a stored lookup table, and interpolation and other methods are used when necessary. Of course, other ways of determining the control signal of the proportional solenoid valve 5 can also be envisioned, such as establishing a calculation model. The required brake pressure can also be determined based on a lookup table or other methods.

[0063] After the control signal of the proportional solenoid valve 5 is determined, the proportional solenoid valve 5 is controlled based on the determined control signal of the proportional solenoid valve 5 ( S06 ) to be operated.

[0064] Then, the actual brake pressure BrkPress_Act is obtained, for example, by a brake pressure sensor (S07). The difference between the required brake pressure and the actual brake pressure BrkPress_Gap is calculated (S08):

[0065] BrkPress_Gap=BrkPress_Des-BrkPress_Act.

[0066] It is determined whether the absolute value of BrkPress_Gap is not greater than 50 kPa (S09). If the absolute value of BrkPress_Gap is not greater than 50 kPa, it indicates that the gas flow provided by the proportional solenoid valve 5 meets the braking control requirements. Therefore, the first valve 6 and the second valve 7 are both closed (S10), and the braking system enters a pressure-maintaining state.

[0067] If the absolute value of BrkPress_Gap is greater than 50 kPa, it is further determined whether the value of BrkPress_Gap itself is greater than 50 kPa (S11). If the value of BrkPress_Gap itself is greater than 50 kPa, it indicates that the gas flow provided by the proportional solenoid valve 5 is insufficient to meet the braking requirement and more intake air is needed. Therefore, the first valve 6 and the second valve 7 are both turned on (S12), and the braking system enters the stamping compensation state, realizing the rapid establishment of braking pressure.

[0068] If the value of BrkPress_Gap itself is not greater than 50 kPa, it indicates that BrkPress_Gap is negative and less than -50 kPa, indicating that further pressure release is required. Therefore, the first valve 6 is closed and the second valve 7 is turned on (S13), and the system enters the pressure release compensation state to achieve rapid release of the brake pressure.

[0069] As can be seen from the above embodiments, a parallel passage is connected in parallel with the proportional solenoid valve, and by controlling the parallel passage, the diameter of the proportional solenoid valve can be compensated, thereby realizing the rapid establishment and release of the brake pressure. Therefore, the electronically controlled braking system according to the present invention can use the existing proportional solenoid valve 5 to realize faster and more accurate brake system control.

[0070] It is obvious that various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the invention for those skilled in the art. Other embodiments of the invention will be apparent to those skilled in the art from the practice of the invention disclosed in this specification. This specification and the examples disclosed therein should be considered to be illustrative only.

Claims

1. An electric control braking system for engineering machinery, the electric control braking system comprising: A gas storage device (1) for storing a gaseous medium; A hydraulic brake (4) for applying braking force; A brake drive device (3) for driving the hydraulic brake (4) using a gas medium; A gas medium control unit (2), which connects the gas storage device (1) to the brake drive device (3), thereby controlling the flow rate of the gas medium loaded on the brake drive device (3); It is characterized in that The gas medium control unit (2) comprises a first control branch and a second control branch which are connected in parallel with each other.

2. The electronically controlled braking system according to claim 1, characterized in that: The first control branch comprises a proportional solenoid valve (5), which controls the flow rate of the gas medium in the first control branch based on a received command signal.

3. The electronically controlled braking system according to claim 1, characterized in that: The second control branch includes a valve mechanism which has three functional positions: In the first functional position, the second control branch is conducting, so that the gas medium can flow from the gas storage device (1) to the brake drive device (3) through the second control branch; In the second functional position, the second control branch is disconnected, so that gas cannot flow from the gas storage device through the second control branch to the brake drive device (3); In a third functional position, the second control branch connects the brake actuator (3) to the atmosphere.

4. The electronically controlled braking system according to claim 3, characterized in that: The valve mechanism comprises a first valve (6) and a second valve (7) connected in series with each other.

5. The electronically controlled braking system according to claim 4, characterized in that: The first valve (6) and the second valve (7) have the same structure, and both the first valve (6) and the second valve (7) are two-position three-way valves.

6. The electronically controlled braking system according to claim 5, characterized in that: The first interface (61) of the first valve (6) is connected to the gas storage device (1); The second port (62) of the first valve (6) is connected to the second port (72) of the second valve (7); The third port (63) of the first valve (6) leads to the atmosphere; The first interface (71) of the second valve (7) is connected to the brake drive device (3); The third port (73) of the second valve (7) leads to the atmosphere.

7. The electronically controlled braking system according to claim 6, characterized in that: In the first functional position, the first valve (6) and the second valve (7) are both open; In the second functional position, both the first valve (6) and the second valve (7) are closed; In the third functional position, the first valve (6) is closed and the second valve (7) is open.

8. The electronically controlled braking system according to claim 4, characterized in that: The first valve (6) and the second valve (7) are integrated in a valve block.

9. The electronically controlled braking system according to claim 1, characterized in that: The first control branch and the second control branch are integrated into a valve block.

10. An engineering machine, comprising the electric control braking system according to any one of claims 1 to 9.

11. A method for controlling an electronically controlled braking system according to any one of claims 1 to 9, the method comprising the following steps: Acquiring an operating signal of a brake operating device (S01); determining a brake control signal based on the manipulation signal (S02); The first control branch and the second control branch are controlled based on the brake control signal (S05-S13).

12. The method according to claim 11, characterized in that Controlling the first control branch and the second control branch based on the brake control signal further includes: determining a required brake pressure based on the brake control signal; Determining a first branch control signal for controlling the first control branch based on the brake control signal, and operating the first control branch based on the first branch control signal; Acquiring an actual brake pressure of the first control branch; calculating a difference between a required brake pressure and an actual brake pressure of the first control branch; If the absolute value of the difference is not greater than the threshold value, the second control branch is disconnected, so that the gas cannot flow from the gas storage device to the brake drive device (3) through the second control branch. If the absolute value of the difference is greater than the threshold value and the difference is a positive value, the second control branch is turned on, so that the gas medium can flow from the gas storage device (1) to the brake drive device (3) through the second control branch. If the absolute value of the difference is greater than a threshold value and the difference is negative, the second control branch causes the brake actuator (3) to be connected to the atmosphere.

Images