Motor air suction prevention method and device and hydrostatic drive vehicle

Abstract

The invention provides a motor air suction prevention method and device and a hydrostatic driving vehicle, a hydrostatic driving system comprises a pump and a motor, the hydrostatic driving system is used for transmitting power between an engine and driving wheels, and the method comprises the steps that in response to operation of stepping on a brake pedal, the angle change rate of the brake pedal is obtained, and the angle change rate of the brake pedal is obtained; the angle change rate is the ratio of the rotation angle of the brake pedal to the rotation duration of the brake pedal; and under the condition that the angle change rate is larger than or equal to the preset threshold value, the displacement of the pump is controlled to be 0, the motor is controlled to increase the displacement according to the preset rate until the maximum displacement of the motor is achieved, and the problem that in the prior art, the cost is high when an oil supplementing pipeline is used for preventing air suction of the motor is solved.

Description

Technical Field

[0001] The present invention relates to the field of hydrostatic drive, and in particular to a motor anti-cavitation method, a motor anti-cavitation device, a computer program product and a hydrostatic drive vehicle. Background Art

[0002] Hydrostatic drive systems are widely used in the travel drive and working device drive fields of construction machinery and agricultural machinery. When emergency braking conditions occur, the motor may fail due to air absorption and be damaged, affecting the normal use of the entire machine.

[0003] At present, the replenishment pipeline can be connected to the motor high-pressure oil port, and an accumulator and a one-way valve can be added. Under the motor braking condition, the replenishment oil directly enters the motor for replenishment. The solution of directly replenishing the motor requires additional accumulators, one-way valves and pipeline components, which increases costs, and some equipment cannot be installed due to limited space. In addition, for some applications, the frequency of emergency braking conditions is not high. Summary of the invention

[0004] The main purpose of the present application is to provide a motor anti-cavitation method, device, computer program product and hydrostatic drive vehicle, so as to at least solve the problem of high cost of preventing motor cavitation by using oil replenishment pipeline in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a motor anti-cavitation method is provided, the hydrostatic drive system includes a pump and a motor, the hydrostatic drive system is used to transmit power between the engine and the drive wheels, the method includes: in response to the operation of stepping on the brake pedal, obtaining the angle change rate of the brake pedal, the angle change rate is the ratio of the rotation angle of the brake pedal to the rotation time of the brake pedal; when the angle change rate is greater than or equal to a predetermined threshold value, controlling the displacement of the pump to 0, and controlling the motor to increase the displacement at a predetermined rate until the maximum displacement of the motor is reached.

[0006] Optionally, when the angle change rate is greater than a predetermined threshold, the motor is controlled to increase its displacement at a predetermined rate, including: when the angle change rate is greater than a predetermined threshold, the displacement of the motor is controlled to remain unchanged, and the displacement of the pump is controlled to be 0; in response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, when the speed of the motor is greater than a predetermined speed, the motor is controlled to increase its displacement at the predetermined rate, or, in response to the operation of releasing the brake pedal and stepping on the accelerator pedal, the displacement of the motor is controlled to remain unchanged, and the pump is controlled to increase its displacement.

[0007] Optionally, in response to releasing the brake pedal and not pressing the accelerator pedal, after controlling the motor to increase the displacement at the predetermined rate when the speed of the motor is greater than a predetermined speed, the method further includes: in response to releasing the brake pedal and not pressing the accelerator pedal, controlling the motor to increase the displacement at the predetermined rate until the displacement of the motor is equal to the maximum displacement, and controlling the displacement of the pump to be 0; in response to releasing the brake pedal and pressing the accelerator pedal, controlling the displacement of the motor to remain unchanged, and controlling the pump to increase the displacement.

[0008] Optionally, after acquiring the angle change rate of the brake pedal, the method further includes: when the angle change rate is less than the predetermined threshold, controlling the displacement of the motor to be the maximum displacement of the motor, and controlling the displacement of the pump to be 0.

[0009] Optionally, in response to the operation of releasing the brake pedal and pressing the accelerator pedal, the displacement of the motor is controlled to remain unchanged, and the pump is controlled to increase the displacement, the method also includes: in response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, the displacement of the pump is controlled to increase to the maximum displacement of the pump, and the displacement of the motor is controlled to decrease to the minimum displacement of the pump.

[0010] Optionally, in response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, the displacement of the pump is controlled to increase to the maximum displacement of the pump, and the displacement of the motor is controlled to decrease to the minimum displacement of the pump. The method further includes: in response to the operation of releasing the accelerator pedal, controlling the displacement of the motor to be the maximum displacement of the motor, and controlling the displacement of the pump to 0.

[0011] Optionally, obtaining the angle change rate of the brake pedal includes: obtaining the rotation angle of the brake pedal detected by the angle sensor on the brake pedal, obtaining the recorded duration of the angle sensor indication change, and obtaining the rotation duration of the brake pedal; calculating the ratio of the rotation angle of the brake pedal to the rotation duration of the brake pedal to obtain the angle change rate.

[0012] According to another aspect of the present application, a motor anti-cavitation device is provided, wherein a hydrostatic drive system comprises a pump and a motor, wherein the hydrostatic drive system is used to transmit power between an engine and drive wheels, and wherein the device comprises: an acquisition unit, used to acquire an angle change rate of the brake pedal in response to a brake pedal operation, wherein the angle change rate is a ratio of a rotation angle of the brake pedal to a rotation duration of the brake pedal; and a first control unit, used to control a displacement of the pump to 0 when the angle change rate is greater than or equal to a predetermined threshold value, and to control the motor to increase its displacement at a predetermined rate until the maximum displacement of the motor is reached.

[0013] According to another aspect of the present application, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, any one of the methods described above is implemented.

[0014] According to another aspect of the present application, a hydrostatic drive vehicle is provided, comprising: a hydrostatic drive system, one or more processors, a memory, and one or more programs, wherein the hydrostatic drive system comprises a pump and a motor, the hydrostatic drive system is used to transfer power between an engine and drive wheels, the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of the methods described.

[0015] By applying the technical solution of the present application, in the above-mentioned motor anti-cavitation method, the angle change rate of the brake pedal is monitored when the brake pedal is stepped on. If the angle change rate is greater than or equal to a predetermined threshold value, it indicates emergency braking, and the displacement of the motor is directly changed to the maximum displacement. The risk angle of motor cavitation has caused motor failure, so the motor is controlled to increase the displacement at a predetermined rate, which greatly reduces the risk of motor cavitation. There is no need to add an oil replenishing line to avoid motor cavitation, which solves the problem of high cost of using an oil replenishing line to prevent motor cavitation in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic flow chart of a motor anti-cavitation method provided according to an embodiment of the present application is shown;

[0017] Figure 2 A schematic flow chart of a method for preventing cavitation under emergency working conditions provided in accordance with an embodiment of the present application is shown;

[0018] Figure 3 A schematic diagram of a process of re-accelerating during a motor displacement increase under an emergency working condition provided in an embodiment of the present application is shown;

[0019] Figure 4A schematic flow chart of another motor anti-cavitation method provided according to an embodiment of the present application is shown.

[0020] The above drawings include the following reference numerals:

[0021] 102, processor; 104, memory; 106, transmission device; 108, input and output devices. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0026] Hydrostatically driven vehicle: A vehicle that is driven by a closed hydraulic system consisting of a pump and a motor.

[0027] As introduced in the background technology, the prior art uses oil replenishment pipelines to prevent motor cavitation, which is costly. To solve this technical problem, the embodiments of the present application provide a motor anti-cavitation method, device, computer program product and hydrostatic drive vehicle.

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] In this embodiment, a motor anti-cavitation method running on a mobile terminal, a computer terminal or a similar computing device is provided. The hydrostatic drive system includes a pump and a motor. The hydrostatic drive system is used to transmit power between the engine and the drive wheels. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0030] Figure 1 1 is a flow chart of a method for preventing motor cavitation according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0031] Step S201, in response to the operation of stepping on the brake pedal, obtaining the angle change rate of the brake pedal, wherein the angle change rate is the ratio of the rotation angle of the brake pedal to the rotation time of the brake pedal;

[0032] Step S202, when the angle change rate is greater than or equal to a predetermined threshold, control the displacement of the pump to be 0, and control the motor to increase the displacement at a predetermined rate until the maximum displacement of the motor is reached.

[0033] In the above-mentioned motor anti-cavitation method, the angle change rate of the brake pedal is monitored when the brake pedal is stepped on. If the angle change rate is greater than or equal to a predetermined threshold value, it indicates emergency braking. The displacement of the motor is directly changed to the maximum displacement. The risk angle of motor cavitation has caused motor failure. Therefore, the motor is controlled to increase the displacement at a predetermined rate, which greatly reduces the risk of motor cavitation. There is no need to add an oil replenishing line to avoid motor cavitation, which solves the problem of high cost of using an oil replenishing line to prevent motor cavitation in the prior art.

[0034] It should be noted that for hydrostatically driven vehicles, the engine usually has two control modes: fixed speed and variable speed. Fixed speed control is suitable for vehicles with lower speeds, and variable speed control is suitable for vehicles with higher speeds. Motor air suction problems usually occur in vehicles with higher speeds during emergency braking. Therefore, the above-mentioned motor air suction prevention method is suitable for vehicles with variable speed control. Of course, vehicles with fixed speed control may also have motor air suction problems, and the above-mentioned motor air suction prevention method is also applicable.

[0035] In order to meet driving needs, in an optional implementation, as Figure 2 As shown, the above step S202 includes:

[0036] Step S2021, when the angle change rate is greater than a predetermined threshold, controlling the displacement of the motor to remain unchanged, and controlling the displacement of the pump to be 0;

[0037] Step S2022, in response to the operation of releasing the above-mentioned brake pedal and not pressing the accelerator pedal, when the rotation speed of the above-mentioned motor is greater than the predetermined rotation speed, the above-mentioned motor is controlled to increase the displacement at the above-mentioned predetermined rate, or, in response to the operation of releasing the above-mentioned brake pedal and pressing the above-mentioned accelerator pedal, the displacement of the above-mentioned motor is controlled to remain unchanged and the above-mentioned pump is controlled to increase the displacement.

[0038] In the above embodiment, during the braking process, the original high-pressure side of the closed system becomes the low-pressure side, and the original low-pressure side becomes the high-pressure side, the pump changes to the motor working condition, the motor changes to the pump working condition, and the oil inlet of the motor changes from high pressure to low pressure. At this time, the motor inlet must ensure the minimum pressure. Under the premise of the same speed, the smaller the motor displacement, the smaller the required minimum inlet pressure, and the more favorable it is to the motor. When the above angle change rate is greater than the predetermined threshold, it indicates that the emergency braking condition has been entered, the motor displacement maintains the current displacement, the pump displacement quickly changes to zero, and the motor displacement is not increased. The required minimum inlet pressure will not increase rapidly. In this way, the motor can be prevented from being damaged by air suction. According to driving needs, it is determined whether to release the brake pedal and accelerate again. If the brake pedal is released without acceleration, when the motor reaches the predetermined speed, the motor displacement begins to increase, and the vehicle speed gradually drops to zero, and the formulation is completed; if the brake pedal is released to accelerate, the motor maintains the current displacement, and the pump displacement gradually increases to ensure that the vehicle accelerates. The required displacement values ​​of the pump and motor are recalculated according to driving needs, and the variables are completed until the target vehicle speed is reached.

[0039] In order to meet driving needs at any time, in an optional implementation, Figure 3 As shown, in response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, when the rotation speed of the motor is greater than the predetermined rotation speed, after controlling the motor to increase the displacement at the predetermined rate, the method further includes:

[0040] Step S301, in response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, controlling the motor to increase displacement at the predetermined rate until the displacement of the motor is equal to the maximum displacement, and controlling the displacement of the pump to be 0;

[0041] Step S302, in response to the operation of releasing the brake pedal and stepping on the accelerator pedal, controlling the displacement of the motor to remain unchanged, and controlling the pump to increase the displacement.

[0042] In the above embodiment, when the motor displacement increases, it is determined again whether the brake pedal is released and the vehicle is accelerated again. If the vehicle is not accelerated, the motor changes to the maximum displacement until the vehicle stops. If the vehicle is accelerated again, the motor maintains the current displacement, and the pump displacement gradually increases to ensure that the vehicle accelerates. The control logic of determining whether the accelerator pedal is released and the vehicle is accelerated again is executed again.

[0043] In order to achieve braking, in an optional implementation manner, after obtaining the angle change rate of the brake pedal, the method further includes:

[0044] Step S401, when the angle change rate is less than the predetermined threshold, the displacement of the motor is controlled to be the maximum displacement of the motor, and the displacement of the pump is controlled to be 0.

[0045] In the above embodiment, when the angle change rate does not reach the predetermined threshold, the pump and motor variable paths are executed in a normal state, the displacement of the motor is controlled to be the maximum displacement of the motor, and the displacement of the pump is controlled to be 0, so as to gradually reduce the vehicle speed to zero.

[0046] In order to achieve acceleration, in an optional implementation manner, in response to the operation of releasing the brake pedal and stepping on the accelerator pedal, after controlling the displacement of the motor to remain unchanged and controlling the pump to increase the displacement, the method further includes:

[0047] Step S501, in response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, the displacement of the pump is controlled to increase to the maximum displacement of the pump, and the displacement of the motor is controlled to decrease to the minimum displacement of the pump.

[0048] In the above embodiment, in response to the operation of not releasing the above accelerator pedal, during the acceleration process, as the engine speed increases and the pump displacement increases, the vehicle speed gradually increases. When the engine speed reaches the maximum speed, the pump displacement continues to increase to the maximum displacement. At this time, the motor needs to gradually change from the maximum displacement to the minimum displacement, and the vehicle speed gradually reaches the maximum.

[0049] In order to meet the idle condition, in an optional implementation manner, in response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, after controlling the displacement of the pump to increase to the maximum displacement of the pump and controlling the displacement of the motor to decrease to the minimum displacement of the pump, the method further includes:

[0050] Step S601, in response to the operation of releasing the accelerator pedal, controlling the displacement of the motor to be the maximum displacement of the motor, and controlling the displacement of the pump to be 0.

[0051] In the above embodiment, when the accelerator pedal is released, the engine speed gradually drops to idle speed, the motor changes from minimum displacement to maximum displacement, and then the pump displacement changes from maximum displacement to zero displacement, and the vehicle speed gradually drops to zero.

[0052] In order to detect the angle change rate of the brake pedal in real time, in an optional implementation, the above step S201 includes:

[0053] Step S2011, obtaining the rotation angle of the brake pedal detected by the angle sensor on the brake pedal, obtaining the recorded duration of the change in the indication of the angle sensor, and obtaining the rotation duration of the brake pedal;

[0054] Step S2012, calculating the ratio of the rotation angle of the brake pedal to the rotation time of the brake pedal to obtain the angle change rate.

[0055] In the above embodiment, the rotation angle of the brake pedal is detected by an angle sensor installed on the brake pedal, and the rotation duration is synchronously timed and recorded, so that the angle change rate is obtained by calculating the ratio of the rotation angle of the brake pedal to the rotation duration of the brake pedal.

[0056] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the motor anti-air suction method of the present application will be described in detail below in combination with specific embodiments.

[0057] This embodiment relates to a specific method for preventing motor from sucking air. Figure 4 As shown, the following steps are included:

[0058] Step S1: During the braking process, the original high-pressure side of the closed system becomes the low-pressure side, and the original low-pressure side becomes the high-pressure side. The pump changes to the motor mode, and the motor changes to the pump mode. The oil inlet of the motor changes from high pressure to low pressure. At this time, the motor inlet must ensure the minimum pressure. Under the premise of the same speed, the smaller the motor displacement, the smaller the required minimum inlet pressure, and the more beneficial it is to the motor. When an emergency braking condition occurs, the electronic controller can monitor the rate of change of the pedal angle and set a certain limit. When the angle change rate reaches the set value, the variable path of the pump and motor is: the motor displacement maintains the current displacement, and the pump displacement quickly changes to zero. In this way, damage caused by motor suction can be avoided. When the angle change rate does not reach the set value, the variable path of the pump and motor is executed in a normal state.

[0059] Step S2: According to driving needs, determine whether to release the brake pedal and accelerate again. If the brake pedal is released without acceleration, the motor displacement begins to increase when the motor reaches a certain set speed setting value; if the brake pedal is released to accelerate, the motor maintains the current displacement, and the pump displacement gradually increases to ensure that the vehicle accelerates. The required displacement values ​​of the pump and motor are recalculated according to driving needs, and the variables are completed until the target vehicle speed is reached.

[0060] Step S3: During the process of increasing the motor displacement, it is determined again whether the brake pedal is released and the vehicle is accelerated again. If the vehicle is not accelerated, the motor will be at the maximum displacement until the vehicle stops. If the vehicle is accelerated again, the motor will maintain the current displacement and the pump displacement will be gradually increased to ensure that the vehicle accelerates. The control logic of determining whether the accelerator pedal is released and the vehicle is accelerated again will be executed again.

[0061] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0062] The embodiment of the present application also provides a motor anti-air suction device. It should be noted that the motor anti-air suction device of the embodiment of the present application can be used to execute the motor anti-air suction method provided by the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0063] The following is an introduction to the motor anti-cavitation device provided in the embodiment of the present application. The hydrostatic drive system includes a pump and a motor. The hydrostatic drive system is used to transmit power between the engine and the drive wheel. The device includes:

[0064] an acquisition unit, configured to acquire an angle change rate of the brake pedal in response to a brake pedal operation, wherein the angle change rate is a ratio of a rotation angle of the brake pedal to a rotation duration of the brake pedal;

[0065] The first control unit is used to control the displacement of the pump to 0 when the angle change rate is greater than or equal to a predetermined threshold value, and control the motor to increase the displacement at a predetermined rate until the maximum displacement of the motor is reached.

[0066] In the above-mentioned motor anti-cavitation method, the angle change rate of the brake pedal is monitored when the brake pedal is stepped on. If the angle change rate is greater than or equal to a predetermined threshold value, it indicates emergency braking. The displacement of the motor is directly changed to the maximum displacement. The risk angle of motor cavitation has caused motor failure. Therefore, the motor is controlled to increase the displacement at a predetermined rate, which greatly reduces the risk of motor cavitation. There is no need to add an oil replenishing line to avoid motor cavitation, which solves the problem of high cost of using an oil replenishing line to prevent motor cavitation in the prior art.

[0067] It should be noted that for hydrostatically driven vehicles, the engine usually has two control modes: fixed speed and variable speed. Fixed speed control is suitable for vehicles with lower speeds, and variable speed control is suitable for vehicles with higher speeds. Motor air suction problems usually occur in vehicles with higher speeds during emergency braking. Therefore, the above-mentioned motor air suction prevention method is suitable for vehicles with variable speed control. Of course, vehicles with fixed speed control may also have motor air suction problems, and the above-mentioned motor air suction prevention method is also applicable.

[0068] In order to meet driving needs, in an optional implementation, as Figure 2 As shown, the first control unit includes:

[0069] A first control module, configured to control the displacement of the motor to remain unchanged and the displacement of the pump to be 0 when the angle change rate is greater than a predetermined threshold;

[0070] The second control module is used for controlling the motor to increase its displacement at the predetermined rate in response to the operation of releasing the brake pedal and not pressing the accelerator pedal when the rotation speed of the motor is greater than the predetermined rotation speed, or, in response to the operation of releasing the brake pedal and pressing the accelerator pedal, controlling the displacement of the motor to remain unchanged and controlling the pump to increase its displacement.

[0071] In the above embodiment, during the braking process, the original high-pressure side of the closed system becomes the low-pressure side, and the original low-pressure side becomes the high-pressure side, the pump changes to the motor working condition, the motor changes to the pump working condition, and the oil inlet of the motor changes from high pressure to low pressure. At this time, the motor inlet must ensure the minimum pressure. Under the premise of the same speed, the smaller the motor displacement, the smaller the required minimum inlet pressure, and the more favorable it is to the motor. When the above angle change rate is greater than the predetermined threshold, it indicates that the emergency braking condition has been entered, the motor displacement maintains the current displacement, the pump displacement quickly changes to zero, and the motor displacement is not increased. The required minimum inlet pressure will not increase rapidly. In this way, the motor can be prevented from being damaged by air suction. According to driving needs, it is determined whether to release the brake pedal and accelerate again. If the brake pedal is released without acceleration, when the motor reaches the predetermined speed, the motor displacement begins to increase, and the vehicle speed gradually drops to zero, and the formulation is completed; if the brake pedal is released to accelerate, the motor maintains the current displacement, and the pump displacement gradually increases to ensure that the vehicle accelerates. The required displacement values ​​of the pump and motor are recalculated according to driving needs, and the variables are completed until the target vehicle speed is reached.

[0072] In order to meet driving needs at any time, in an optional implementation, Figure 3 As shown, the above device also includes:

[0073] a second control unit, configured to, in response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, control the motor to increase the displacement at the predetermined rate when the rotation speed of the motor is greater than a predetermined rotation speed, and then, in response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, control the motor to increase the displacement at the predetermined rate until the displacement of the motor is equal to the maximum displacement, and control the displacement of the pump to be 0;

[0074] The third control unit is used to control the displacement of the motor to remain unchanged and control the pump to increase the displacement in response to the operation of releasing the brake pedal and stepping on the accelerator pedal.

[0075] In the above embodiment, when the motor displacement increases, it is determined again whether the brake pedal is released and the vehicle is accelerated again. If the vehicle is not accelerated, the motor changes to the maximum displacement until the vehicle stops. If the vehicle is accelerated again, the motor maintains the current displacement, and the pump displacement gradually increases to ensure that the vehicle accelerates. The control logic of determining whether the accelerator pedal is released and the vehicle is accelerated again is executed again.

[0076] In order to achieve braking, in an optional implementation, the device further includes:

[0077] The fourth control unit is used to control the displacement of the motor to be the maximum displacement of the motor and control the displacement of the pump to be 0 after obtaining the angle change rate of the brake pedal and when the angle change rate is less than the predetermined threshold.

[0078] In the above embodiment, when the angle change rate does not reach the predetermined threshold, the pump and motor variable paths are executed in a normal state, the displacement of the motor is controlled to be the maximum displacement of the motor, and the displacement of the pump is controlled to be 0, so as to gradually reduce the vehicle speed to zero.

[0079] In order to achieve acceleration, in an optional implementation manner, the above device further includes:

[0080] The fifth control unit is used for controlling the displacement of the motor to remain unchanged and controlling the pump to increase the displacement in response to the operation of releasing the brake pedal and stepping on the accelerator pedal, and then, in response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, controlling the displacement of the pump to increase to the maximum displacement of the pump and controlling the displacement of the motor to decrease to the minimum displacement of the pump.

[0081] In the above embodiment, in response to the operation of not releasing the above accelerator pedal, during the acceleration process, as the engine speed increases and the pump displacement increases, the vehicle speed gradually increases. When the engine speed reaches the maximum speed, the pump displacement continues to increase to the maximum displacement. At this time, the motor needs to gradually change from the maximum displacement to the minimum displacement, and the vehicle speed gradually reaches the maximum.

[0082] In order to meet the idle condition, in an optional implementation manner, the above device further includes:

[0083] a sixth control unit, for controlling the displacement of the pump to increase to the maximum displacement of the pump and controlling the displacement of the motor to decrease to the minimum displacement of the pump in response to the operation of not releasing the accelerator pedal and when the speed of the engine is equal to the maximum speed, and then controlling the displacement of the motor to be the maximum displacement of the motor and controlling the displacement of the pump to be 0 in response to the operation of releasing the accelerator pedal.

[0084] In the above embodiment, when the accelerator pedal is released, the engine speed gradually drops to idle speed, the motor changes from minimum displacement to maximum displacement, and then the pump displacement changes from maximum displacement to zero displacement, and the vehicle speed gradually drops to zero.

[0085] In order to detect the angle change rate of the brake pedal in real time, in an optional implementation, the acquisition unit includes:

[0086] An acquisition module, used to acquire the rotation angle of the brake pedal detected by the angle sensor on the brake pedal, acquire the recorded duration of the change in the indication of the angle sensor, and obtain the rotation duration of the brake pedal;

[0087] The calculation module is used to calculate the ratio of the rotation angle of the brake pedal to the rotation time of the brake pedal to obtain the angle change rate.

[0088] In the above embodiment, the rotation angle of the brake pedal is detected by an angle sensor installed on the brake pedal, and the rotation duration is synchronously timed and recorded, so that the angle change rate is obtained by calculating the ratio of the rotation angle of the brake pedal to the rotation duration of the brake pedal.

[0089] The motor anti-air suction device includes a processor and a memory. The acquisition unit and the first control unit are stored in the memory as program units, and the processor executes the program units stored in the memory to implement corresponding functions. The modules are all located in the same processor; or, the modules are located in different processors in any combination.

[0090] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the problem of high cost of preventing the motor from sucking air through the oil replenishment pipeline in the prior art can be solved by adjusting the kernel parameters.

[0091] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the motor anti-cavitation method.

[0092] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein the motor anti-air suction method is executed when the program is run.

[0093] An embodiment of the present invention provides a hydrostatic drive vehicle, which includes a hydrostatic drive system, a processor, a memory, and a program stored in the memory and executable on the processor. The hydrostatic drive system includes a pump and a motor. The hydrostatic drive system is used to transmit power between an engine and drive wheels. When the processor executes the program, the motor anti-cavitation method is implemented.

[0094] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program initialized with the above-mentioned motor anti-cavitation method.

[0095] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0096] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0097] 1) In the motor anti-cavitation method of the present application, the angle change rate of the brake pedal is monitored when the brake pedal is stepped on. If the angle change rate is greater than or equal to a predetermined threshold value, it indicates emergency braking. The displacement of the motor is directly changed to the maximum displacement. The risk angle of motor cavitation has caused motor failure. Therefore, the motor is controlled to increase the displacement at a predetermined rate, which greatly reduces the risk of motor cavitation. There is no need to add an oil replenishment line to avoid motor cavitation, which solves the problem of high cost of using an oil replenishment line to prevent motor cavitation in the prior art.

[0098] 2) In the motor anti-air suction device of the present application, the angle change rate of the brake pedal is monitored when the brake pedal is stepped on. If the angle change rate is greater than or equal to a predetermined threshold value, it indicates emergency braking. The displacement of the motor is directly changed to the maximum displacement. The risk angle of motor air suction has caused motor failure. Therefore, the motor is controlled to increase the displacement at a predetermined rate, which greatly reduces the risk of motor air suction. There is no need to add an oil replenishing line to avoid motor air suction, which solves the problem of high cost of using an oil replenishing line to prevent motor air suction in the prior art.

[0099] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preventing motor cavitation, characterized in that: A hydrostatic drive system includes a pump and a motor, the hydrostatic drive system is used to transmit power between an engine and a drive wheel, and the method includes: In response to a brake pedal operation, obtaining an angle change rate of the brake pedal, wherein the angle change rate is a ratio of a rotation angle of the brake pedal to a rotation duration of the brake pedal; When the angle change rate is greater than or equal to a predetermined threshold, the displacement of the pump is controlled to be 0, and the motor is controlled to increase the displacement at a predetermined rate until the maximum displacement of the motor is reached.

2. The method according to claim 1, characterized in that When the angle change rate is greater than a predetermined threshold, controlling the motor to increase displacement at a predetermined rate comprises: When the angle change rate is greater than a predetermined threshold, the displacement of the motor is controlled to remain unchanged, and the displacement of the pump is controlled to be 0; In response to the operation of releasing the brake pedal and not pressing the accelerator pedal, when the speed of the motor is greater than a predetermined speed, the motor is controlled to increase the displacement at the predetermined rate, or, in response to the operation of releasing the brake pedal and pressing the accelerator pedal, the displacement of the motor is controlled to remain unchanged and the pump is controlled to increase the displacement.

3. The method according to claim 2, characterized in that In response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, after controlling the motor to increase the displacement at the predetermined rate when the rotation speed of the motor is greater than the predetermined rotation speed, the method further includes: In response to the operation of releasing the brake pedal and not stepping on the accelerator pedal, controlling the motor to increase the displacement at the predetermined rate until the displacement of the motor is equal to the maximum displacement, and controlling the displacement of the pump to be 0; In response to the operation of releasing the brake pedal and stepping on the accelerator pedal, the displacement of the motor is controlled to remain unchanged, and the pump is controlled to increase the displacement.

4. The method according to claim 1, characterized in that: After acquiring the angle change rate of the brake pedal, the method further includes: When the angle change rate is less than the predetermined threshold, the displacement of the motor is controlled to be the maximum displacement of the motor, and the displacement of the pump is controlled to be zero.

5. The method according to claim 3, characterized in that: After controlling the displacement of the motor to remain unchanged and controlling the pump to increase the displacement in response to the operation of releasing the brake pedal and stepping on the accelerator pedal, the method further includes: In response to the operation of not releasing the accelerator pedal, when the engine speed is equal to the maximum speed, the displacement of the pump is controlled to increase to the maximum displacement of the pump, and the displacement of the motor is controlled to decrease to the minimum displacement of the pump.

6. The method according to claim 5, characterized in that In response to the operation of not releasing the accelerator pedal, when the speed of the engine is equal to the maximum speed, after controlling the displacement of the pump to increase to the maximum displacement of the pump and controlling the displacement of the motor to decrease to the minimum displacement of the pump, the method further includes: In response to the operation of releasing the accelerator pedal, the displacement of the motor is controlled to be the maximum displacement of the motor, and the displacement of the pump is controlled to be zero.

7. The method according to any one of claims 1 to 6, characterized in that Obtaining the angle change rate of the brake pedal, including: Obtaining the rotation angle of the brake pedal detected by the angle sensor on the brake pedal, obtaining the recorded duration of the change in the indication of the angle sensor, and obtaining the rotation duration of the brake pedal; The ratio of the rotation angle of the brake pedal to the rotation time of the brake pedal is calculated to obtain the angle change rate.

8. A motor anti-air suction device, characterized in that: A hydrostatic drive system includes a pump and a motor, and the hydrostatic drive system is used to transmit power between an engine and a drive wheel, and the device includes: an acquisition unit, configured to acquire an angle change rate of the brake pedal in response to a brake pedal operation, wherein the angle change rate is a ratio of a rotation angle of the brake pedal to a rotation duration of the brake pedal; The first control unit is used to control the displacement of the pump to 0 when the angle change rate is greater than or equal to a predetermined threshold, and control the motor to increase the displacement at a predetermined rate until the maximum displacement of the motor is reached.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. A hydrostatic drive vehicle, characterized in that: include: A hydrostatic drive system, one or more processors, a memory, and one or more programs, wherein the hydrostatic drive system includes a pump and a motor, and the hydrostatic drive system is used to transfer power between an engine and drive wheels, and the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for executing any one of claims 1 to 7.

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