A power shift control method for a power transmission

Abstract

The application discloses a power reversing control method of a power transmission, wherein when the gearbox performs a reversing action, the gearbox sequentially passes through a deceleration control stage, a reverse starting control stage, a rapid pressure increasing stage and a clutch rapid combination stage; in the deceleration control stage, a continuous fluctuation pressure is given to the selected direction clutch to reduce the vehicle speed to n2, and then the pressure of the selected clutch is kept until the vehicle speed is reduced to n3; in the reverse starting control stage, the pressure of the selected direction clutch is increased until the vehicle speed reaches n4; in the rapid pressure increasing stage, the pressure of the selected direction clutch is continuously increased until the vehicle speed is increased to n0; in the clutch rapid combination stage, the pressure in the selected direction clutch is increased at the maximum speed until the pressure reaches the working pressure. In this way, the reverse fluctuation damping is generated by the engine joint control and the fluctuation pressure of the reverse clutch in the deceleration process of the vehicle, and the speed braking effect is good; through the closed loop control of the speed and the pressure, the clutch pressure increasing speed can be automatically adjusted.

Description

Technical Field

[0001] This invention relates to the field of transmission in engineering and agricultural machinery and equipment, and in particular to a power reversing control method for a power transmission. Background Technology

[0002] Traditional engineering and agricultural machinery with power-driven reversing transmission devices require manual operation to achieve fast, smooth, and reliable performance. This involves operations such as foot braking, reversing, and semi-clutch start-up, which are complex and demanding on the driver. Frequent reversing also increases labor intensity. When operating automatically, reversing requires the addition of braking devices, and the performance changes significantly when starting in reverse under complex working conditions. This results in complex structures, high costs, and unstable performance. Summary of the Invention

[0003] In order to solve the problem of complex transmission and operation in the reversing process of the transmission device in the prior art, the purpose of this invention is to provide a power reversing control method for a power transmission, which generates reverse wave damping by oscillating pressure during the reversing deceleration process of the vehicle, and completes a fast and stable reversing start.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a power reversing control method for a power transmission, the transmission including an output shaft, a forward clutch and a reverse clutch, the power of the engine being transmitted to the output shaft through the forward clutch or the reverse clutch, the power reversing control method for the power transmission including a deceleration control stage, a reverse start control stage, a rapid pressurization stage and a clutch rapid engagement stage performed sequentially.

[0005] When the transmission performs a reversing action, it first enters the deceleration control phase. During the deceleration control phase, after the vehicle speed drops to n1, the current direction clutch releases pressure. Then, after a delay of Y1 time, the pressure of the selector direction clutch is increased to P1. Then, the selector direction clutch is given a continuously fluctuating pressure until the vehicle speed drops to n2. Then, the pressure of the selector clutch is maintained at P1 until the vehicle speed drops to n3. Among these, if the vehicle changes direction from forward to reverse, the current direction clutch is the forward clutch and the selector direction clutch is the reverse clutch; if the vehicle changes direction from reverse to forward, the current direction clutch is the reverse clutch and the selector direction clutch is the forward clutch.

[0006] After the deceleration control phase ends, the transmission enters the reverse start control phase; during the reverse start control phase, the pressure of the direction selection clutch increases at a rate of S1 bar / S until the vehicle speed reaches n4.

[0007] After the reverse start control phase ends, the transmission enters the rapid pressurization phase; during the rapid pressurization phase, the pressure of the directional clutch continues to increase at a rate of S2bar / S until the vehicle speed reaches the target speed n0.

[0008] After the rapid pressurization phase ends, the transmission enters the clutch rapid engagement phase; during the clutch rapid engagement phase, the pressure inside the directional clutch increases at maximum speed until the pressure reaches the working pressure.

[0009] As a preferred option, during the deceleration control phase, when the vehicle speed drops to n3, the controller controls the engine speed to the intermediate speed between idle speed and rated speed.

[0010] As a preferred option, during the deceleration control phase, the peak of the continuous oscillating pressure within the directional clutch is P1, and the trough of the pressure is P2, with Y2 as one cycle of rise and fall.

[0011] Preferably, P1 is the effective starting pressure when the host is in a horizontal state, and the value of P1 is determined according to the calibration value of different equipment.

[0012] As a preferred option, the value of n3 is zero.

[0013] Preferably, a speed sensor for monitoring the rotational speed of the feedback output shaft is installed on the output shaft.

[0014] Preferably, the transmission also includes a forward proportional valve for controlling the pressure inside the forward clutch and a reverse proportional valve for controlling the pressure inside the reverse clutch.

[0015] Preferably, the system also includes a controller for controlling the operation of the gearbox, with both the forward proportional valve and the reverse proportional valve electrically connected to the controller.

[0016] As a preferred option, S2 > S1.

[0017] As a preferred option, S2 and S1 are determined based on driving and riding experience.

[0018] The beneficial effects of the technical solution of the present invention are as follows: During the deceleration of the vehicle, reverse fluctuation damping is generated by the engine control and the fluctuation pressure of the reverse clutch, resulting in good deceleration braking effect, low clutch wear, fewer required components, and a simpler gearbox structure; through closed-loop control of speed and pressure, the clutch pressure speed can be automatically adjusted for various working conditions, which can overcome the resistance of different working conditions, ensure smoothness and speed during start-up, have adaptive capability, and ensure the fast, smooth, safe, reliable and stable reversal of the main engine. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the gearbox transmission principle.

[0020] Figure 2 This is a schematic diagram of the hydraulic system of a gearbox.

[0021] Figure 3 This is a graph showing the vehicle speed and clutch pressure during the direction change process.

[0022] Reference numerals: KV, forward clutch; KR, reverse clutch; Z1, first gear; Z2, second gear; Z3, third gear; Z4, fourth gear; Z5, fifth gear; M1, reverse proportional valve; M2, forward proportional valve; P, oil pump. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. Example

[0028] like Figure 1 and Figure 2 The power transmission shown includes a reverse clutch KV, a forward clutch KR, a forward proportional valve M2 that controls the forward clutch KR, and a reverse proportional valve M1 that controls the reverse clutch KV and the forward clutch KR. By controlling the forward proportional valve M2 and the reverse proportional valve M1, power is transmitted to the output shaft via the reverse clutch KV or the forward clutch KR.

[0029] In this embodiment, as Figure 1 As shown, power is transmitted to the retractable clutch KV or the forward clutch KR via a transmission mechanism. Specifically, the transmission structure includes an input shaft, a drive shaft, a first gear Z1, a second gear Z2, a third gear Z3, a fourth gear Z4, and a fifth gear Z5. The retractable clutch KV and the forward clutch KR have the same structure. In the retractable clutch KV, the housing of the retractable clutch KV is fixed to the output shaft. Multiple inner friction plates and multiple outer friction plates of the retractable clutch KV are alternately arranged. The inner friction plates of the retractable clutch KV are sleeved on the fourth gear Z4 and splined. The outer friction plates of the retractable clutch KV are located on the retractable clutch. The KV is housed within a housing and connected by splines; in the forward clutch KR, the housing of the forward clutch KR is fixed on the output shaft, and multiple inner friction plates and multiple outer friction plates of the forward clutch KR are alternately arranged. The inner friction plates of the forward clutch KR are sleeved on the third gear Z3 and connected by splines, and the outer friction plates of the forward clutch KR are located inside the housing of the forward clutch KR and connected by splines; the first gear Z1 and the second gear Z2 are fixed on the input shaft, and the fifth gear Z5 is fixed on the transmission shaft. The first gear Z1 meshes with the third gear Z3 through the fifth gear Z5, and the second gear Z2 meshes with the fourth gear Z4.

[0030] In other embodiments, the specific scheme of the transmission structure can be found in patent documents with publication numbers CN2599318Y, CN117231711A and CN202125581U.

[0031] In this embodiment, a speed sensor for monitoring and feeding back the rotational speed is installed on the output shaft.

[0032] In this embodiment, a controller is also included, which has functions such as driving a proportional valve, CAN bus communication, and frequency sampling.

[0033] The oil pump draws oil from the oil sump, and after passing through the first filter, the oil enters the gear position control valve assembly, the forward proportional valve M2, and the reverse proportional valve. The filtered oil is then delivered to various lubrication points of the transmission via branch lines and the cooler.

[0034] After the vehicle changes direction from reverse to forward, the forward proportional valve M2 controls the forward clutch KV to enter the working state, and the reverse proportional valve M1 controls the reverse clutch KR to exit the working state. Oil enters the forward clutch KV to engage the inner and outer friction plates of the forward clutch KV. Power is output from the output shaft through the input shaft, the second gear Z2, the fourth gear Z4 and the forward clutch KV.

[0035] After the vehicle changes direction from forward to reverse, the reverse proportional valve M1 controls the reverse clutch KR to enter the working state, and the forward proportional valve M2 controls the forward clutch KV to exit the working state. Oil enters the reverse clutch KR to engage the inner and outer friction plates of the reverse clutch KR. Power is output from the output shaft through the input shaft, the first gear Z1, the fifth gear Z5, the third gear Z3 and the reverse clutch KR. Example

[0036] A power reversing control method for a power transmission as described in Embodiment 1 above:

[0037] The power reversal control method includes four stages performed sequentially: deceleration control stage, reverse start control stage, rapid pressurization stage, and clutch rapid engagement stage.

[0038] The deceleration control phase includes the following: when the vehicle is changing direction, the speed is reduced to n1 by controlling the engine and gear, and then the clutch in the current direction is depressurized; if the vehicle changes direction from forward to reverse, the clutch in the current direction is the forward clutch KV; if the vehicle changes direction from reverse to forward, the clutch in the current direction is the reverse clutch KR; thus improving the safety and reliability of vehicle reversing.

[0039] Then, after a delay of Y1 time, the proportional valve increases the pressure of the directional clutch to P1;

[0040] Then, the proportional valve applies a continuously fluctuating pressure to the directional clutch until the vehicle speed drops to n2; where, if the vehicle changes direction from forward to reverse, the directional clutch becomes the reverse clutch KR; if the vehicle changes direction from reverse to forward, the directional clutch becomes the forward clutch KV; this fluctuating pressure can effectively reduce speed and brake, while having little impact on clutch wear, and has the characteristics and effects of fast, reliable and safe speed reduction.

[0041] When the vehicle speed drops to n2, the proportional valve will maintain the clutch pressure at P1 until the vehicle speed drops to n3;

[0042] Then, the reverse start control phase begins: the proportional valve pressurizes the clutch at a speed of S1 bar / S to select the direction until the vehicle speed reaches n4; where the pressure P3 when the vehicle speed reaches n4 is...

[0043] The rapid pressurization phase includes continuing to pressurize the directional clutch at a speed of S2 bar / S until the vehicle speed reaches n0 and the pressure reaches P4; where S2 > S1.

[0044] The specific content of the clutch rapid engagement phase includes the proportional valve pressurizing the clutch in the selected direction at maximum speed until the pressure reaches the working pressure P5; this allows the clutch to quickly transition from dynamic friction to static friction, reducing clutch slippage wear and time, effectively increasing clutch reliability, and making reversing faster.

[0045] With this setup, during vehicle deceleration, reverse fluctuation damping is generated through engine control and reverse clutch pressure fluctuations, resulting in good deceleration braking effect and low clutch wear. Through closed-loop control of speed and pressure, the clutch pressure speed can be automatically adjusted to meet various working conditions, overcome the resistance of different working conditions, ensure smooth and rapid start-up, and have adaptive capabilities, ensuring fast, smooth, safe, reliable and stable main engine reversal.

[0046] In this embodiment, during the deceleration control phase, once the vehicle speed drops to n3, the controller implements closed-loop control by controlling the engine speed to the midpoint between idle speed and rated speed. Furthermore, the value of n3 is zero. In other embodiments, n3 can be any other value close to zero.

[0047] In this embodiment, S1 and S2 can be set automatically according to the driving experience.

[0048] In this embodiment, as Figure 3As shown, during the deceleration control phase, the peak pressure in the continuously fluctuating pressure within the directional clutch is P1, and the trough pressure is P2, with Y2 as one cycle. Furthermore, P1 represents the peak pressure of the continuously fluctuating pressure, and P2 is the effective starting pressure when the main unit is in a horizontal state. The value of P1 is determined based on the calibration values ​​of different equipment.

[0049] In this embodiment, as Figure 3 As shown, the time node when the vehicle speed reaches n1 is T1, the time node when the vehicle speed reaches n2 is T2, the time node when the vehicle speed reaches n3 is T3, the time node when the vehicle speed reaches n4 is T4, and the time node when the vehicle speed reaches n5 is T5.

[0050] This embodiment takes the PT120 tractor as an example: the peak pressure P1 is 2.5 bar, the trough value P2 is about 1.5 bar lower than the peak value, and the period Y2 is 100 ms; when the PT120 tractor performs reversing using the above method, the controller TCU accepts the reversing operation.

[0051] The transmission enters the first deceleration control stage; in this stage, the TCU controls the engine speed and transmission gear to reduce the vehicle speed to 5 km / h, and then the current clutch releases pressure; then, through the corresponding proportional valve of the directional clutch, a continuous fluctuating pressure is applied to the directional clutch until the vehicle speed is below 0.5 km / h; then, the pressure of the directional clutch is maintained at the effective starting pressure until the vehicle speed drops to zero; then, closed-loop control is implemented by linking the engine speed to the intermediate speed between idle speed and rated speed.

[0052] Then, the second stage of reverse start control begins; in this stage, the proportional valve gradually pressurizes the directional clutch at a rate of 1 bar / s until the reverse vehicle speed n4 reaches 1.5 km / h and the directional clutch pressure reaches P3.

[0053] Then it enters the third stage of rapid pressurization; in this stage, the proportional valve gradually pressurizes the directional clutch at a speed of 3 bar / s until the vehicle speed approaches the target speed n0.

[0054] Then it enters the fourth stage of rapid clutch engagement; in this stage, the clutch is quickly pressurized to 17 bar, which allows the clutch to quickly transition from dynamic friction to static friction, reducing clutch slippage and wear time, effectively increasing clutch reliability, and making reversing faster.

[0055] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A power reversing control method for a power transmission, the transmission comprising an output shaft, a forward clutch (KV), and a reverse clutch (KR), wherein engine power can be transmitted to the output shaft for output via the forward clutch (KV) or the reverse clutch (KR), characterized in that: The power reversing control method of the power transmission includes a deceleration control stage, a reverse start control stage, a rapid pressurization stage, and a clutch rapid engagement stage performed sequentially. When the transmission performs a reversing action, it first enters the deceleration control phase. During the deceleration control phase, after the vehicle speed drops to n1, the current direction clutch releases pressure. Then, after a delay of Y1 time, the pressure of the selector direction clutch is increased to P1. Then, the selector direction clutch is given a continuously fluctuating pressure until the vehicle speed drops to n2. Then, the pressure of the selector clutch is maintained at P1 until the vehicle speed drops to n3. Among these, if the vehicle changes direction from forward to reverse, the current direction clutch is the forward clutch (KV), and the selector direction clutch is the reverse clutch (KR); if the vehicle changes direction from reverse to forward, the current direction clutch is the reverse clutch (KR), and the selector direction clutch is the forward clutch (KV). After the deceleration control phase ends, the transmission enters the reverse start control phase; during the reverse start control phase, the pressure of the direction selection clutch increases at a rate of S1 bar / s until the vehicle speed reaches n4. After the reverse start control phase ends, the transmission enters the rapid pressurization phase; during the rapid pressurization phase, the pressure of the directional clutch continues to increase at a rate of S2 bar / S until the vehicle speed reaches the target speed n0, where S2 > S1. After the rapid pressurization phase ends, the transmission enters the clutch rapid engagement phase; during the clutch rapid engagement phase, the pressure inside the directional clutch increases at maximum speed until the pressure reaches the working pressure. In the deceleration control phase, the peak of the pressure in the direction selection clutch is P1 and the trough of the pressure is P2. With Y2 as one lifting cycle, P1 is the effective starting pressure when the main unit is in a horizontal state. A speed sensor is installed on the output shaft to monitor the speed of the feedback output shaft. The gearbox also includes a forward proportional valve (M2) for controlling the pressure inside the forward clutch (KV), a reverse proportional valve (M1) for controlling the pressure inside the reverse clutch (KR), and a controller for controlling the gearbox operation. Both the forward proportional valve (M2) and the reverse proportional valve (M1) are electrically connected to the controller.

2. The power reversing control method for a power transmission according to claim 1, characterized in that: During the deceleration control phase, when the vehicle speed drops to n3, the controller controls the engine speed to the intermediate speed between idle speed and rated speed.

3. The power reversing control method for a power transmission according to claim 1, characterized in that: The value of P1 is determined based on the calibration value of different devices.

4. The power reversing control method for a power transmission according to claim 1, characterized in that: The value of n3 is zero.

5. The power reversing control method for a power transmission according to claim 1, characterized in that: S2 and S1 are determined based on the driver and passenger.

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