Method for controlling a coupling system of a mechanical transmission
By controlling the approach and engagement of coupling sections in stages, the problem of complex control in existing coupling systems when switching between high and low speeds is solved, achieving a more flexible and efficient connection process and improving transmission efficiency and system stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2021-09-28
- Publication Date
- 2026-06-30
AI Technical Summary
In the existing technology, the control process of the coupling system in controlling the movement of the clutch, especially when switching between high speed and low speed, is complex and inflexible, making it difficult to achieve a fast and efficient connection process.
A coupling system is employed to control the engagement and disengagement of coupling sections via a hydraulic cylinder and a pressure regulating device. The internal pressure of the hydraulic cylinder is regulated by electric current to control the approach and engagement process of the coupling sections in stages, including rapid approach during a first time interval, followed by gradual slowing down of approach during a modulated time interval, and full engagement when the speed difference is below a predetermined value.
It improves the flexibility and control precision of clutch movement, ensures smooth switching of the coupling system within different speed ranges, reduces friction and wear, and improves transmission efficiency.
Smart Images
Figure CN116249844B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for controlling a coupling system of a mechanical transmission device. Background Technology
[0002] To increase the gear ratio range of traction drives, hydrostatic transmissions with two hydraulic motors are known from the art, operating in parallel in a fluid manner. The drive shaft power can be increased and transmitted, for example, to the axle, via a compound transmission mechanism of the hydrostatic transmission. For example, at low speeds, the two hydraulic motors operate in parallel, thereby allowing high traction. Given a predefined delivery rate of the hydraulic pump and considering the reduced efficiency due to the smaller scanning volume of the hydraulic motors, the speed achievable using two motors is limited.
[0003] To achieve a relatively high drive range, one of the hydraulic motors can therefore be set to zero discharge volume and disconnected from the output by means of a clutch. The full volumetric flow of the hydraulic pump is then directed via the remaining, typically smaller, hydraulic motor, thus allowing for relatively high rotational speeds and therefore relatively high velocities.
[0004] If the two hydraulic motors then re-engage in power transmission, the clutch must be engaged. For this purpose, the hydraulic motors previously disconnected from the output must accelerate from idling to their operating speed. This acceleration must be rapid and as far as possible without the driver noticing. Due to these somewhat contradictory requirements, control of the engagement process is demanding.
[0005] For example, a hydraulic cylinder is used to activate the clutch. Depending on the design, the clutch is engaged either by applying pressure to the hydraulic cylinder (positive clutch) or by releasing pressure from the hydraulic cylinder (negative clutch).
[0006] In principle, in a positive clutch system (and vice versa in a negative clutch system), the clutch engagement process can be divided into two stages. In the first stage, the pressure medium is supplied in such a way that the clutch engages as quickly as possible; that is, the clutch travel is implemented to reach the engagement point in the shortest possible time. The second stage begins at the engagement point, that is, if torque is being transmitted by the clutch. From this point onward, the supply of pressure medium primarily causes an increase in the transmittable torque of the clutch, rather than an increase in the clutch travel.
[0007] Ideally, the first stage is very short in duration and terminates just before the engagement point (the clutch engagement point is defined herein as the clutch position when the clutch makes initial frictional contact and begins to transmit torque between the two different elements). The second stage is then preferably controlled in this manner so that the corresponding hydraulic motor accelerates in the desired manner.
[0008] The present invention relates to a method that enables increased flexibility in the second stage of controlling the movement of different clutch designs. Summary of the Invention
[0009] According to an embodiment of the present invention, a method is provided for controlling a coupling system of a superimposed mechanical transmission device, the coupling system being configured to engage a first drive shaft and a second drive shaft during engagement, the coupling system comprising a hydraulic coupling having two releasable coupling sections, wherein the first coupling section is connected to a first drive shaft and the second coupling section is connected to a second drive shaft, the coupling system further comprising a hydraulic cylinder connected to one of the first coupling section and the second coupling section and configured to engage and disengage the first coupling section from the second coupling section based on pressure within the hydraulic cylinder, wherein the pressure within the hydraulic cylinder is adjustable by means of a pressure regulating device, wherein the pressure regulating device includes an activating device configured to adjust the pressure within the hydraulic cylinder based on a current supplied to the activating device;
[0010] The method includes the following steps:
[0011] a. During a first time interval, current is supplied to the activating device such that the first coupling section and the second coupling section approach each other but have not yet reached the engagement point;
[0012] b. After the first time interval, current is supplied to the activating device during a modulation time interval such that the approach of the first coupling section and the second coupling section is slowed down relative to the approach during the first time interval, wherein the engagement point is reached during the modulation time interval.
[0013] The modulation time interval is divided into a second time interval and a third time interval, wherein the current supplied to the activation device is gradually increased or decreased at a predetermined slope during both the second time interval and the third time interval, and wherein the slope of the current during the second time interval is different from the slope of the current during the third time interval.
[0014] According to a further embodiment of the present invention, a method is provided in which the third time interval is terminated when the speed difference between the first coupling section and the second coupling section is lower than a predetermined value, and current is provided to the activating device such that the first coupling section and the second coupling section are fully engaged with each other.
[0015] According to a further embodiment of the present invention, a method is provided, wherein the first drive shaft is connected to a first hydraulic motor and the second drive shaft is connected to a second hydraulic motor, wherein the first hydraulic motor and the second hydraulic motor are motors of a hydraulic transmission device.
[0016] According to a further embodiment of the present invention, a method is provided in which the coupling system is a mechanical transmission device of a vehicle, positioned between the output shaft of a hydrostatic transmission device comprising multiple motors and a superimposed mechanical transmission device.
[0017] According to a further embodiment of the present invention, a method is provided in which the first time interval is the time used in the engagement process during which a first coupling section and a second coupling section (30) will engage with each other, wherein during the first time interval (t1), the first coupling section and the second coupling section approach each other at the beginning of the engagement process, and then the approach of the first coupling section and the second coupling section is slowed down during the second time interval.
[0018] According to another embodiment of the present invention, a method is provided in which the activating device is an electromagnet. Attached Figure Description
[0019] The invention is described with reference to the accompanying drawings, wherein the same reference numerals denote the same and / or similar and / or corresponding parts of the system. In the drawings:
[0020] Figure 1 A hydraulic diagram is schematically shown based on the current state of affairs in the art;
[0021] Figure 2 The pressure value measured by sensor 54 and the current value delivered to electromagnet 78 via signal line 80 during the closure of coupling system 12 according to a preferred embodiment of the invention are shown.
[0022] Figure 3 A method for estimating an interpolation function according to a preferred embodiment of the present invention is shown, the interpolation function being a function representing the change of venting time t1 with temperature;
[0023] Figure 4 A method for detecting joint points according to a preferred embodiment of the present invention is shown;
[0024] Figure 5 A first method for controlling a coupling system according to a preferred embodiment of the present invention is shown;
[0025] Figure 6 A second method for controlling a coupling system according to a preferred embodiment of the present invention is shown. Detailed Implementation
[0026] The invention is described below with reference to specific embodiments as illustrated in the accompanying drawings. However, the invention is not limited to the specific embodiments described in the following detailed description and shown in the drawings, but rather the described embodiments are merely illustrative of several aspects of the invention, the scope of which is defined by the claims.
[0027] Further modifications and variations of the invention will be apparent to those skilled in the art. Therefore, this description is to be considered to include all described modifications and / or variations of the invention, the scope of which is defined by the claims.
[0028] In this disclosure, the term "pressure medium" means any type of medium that can be pressurized and used to transmit power to various hydraulic components, such as hydraulic oil.
[0029] It should be noted that the specific physical values used to describe some working examples of the invention do not limit the scope of the invention, which is defined by the appended claims.
[0030] according to Figure 1 The traction drive has a hydrostatic transmission 2, which includes a hydraulic press (not shown) that operates as a hydraulic pump in the traction mode of the traction drive and two hydraulic presses 4 and 8 that operate as hydraulic motors in a specified traction mode. On one hand, the two hydraulic motors 4, 8 are connected to the hydraulic pump via working lines in a closed hydraulic circuit. The hydraulic presses are adjustable in terms of their discharge volume, and each is implemented as an axial piston machine with a swashplate design or a bent-shaft design.
[0031] The hydraulic pump is connected to a drive machine, which is configured as a diesel engine, via its drive shaft. The first hydraulic motor 4 (also referred to as the permanent motor in this specification), one of the two hydraulic motors 4 and 8, has a first drive shaft 14, and the second hydraulic motor 8 (also referred to as the temporary motor in this specification) has a second drive shaft 16. A coupling system 12 with two input shafts 14 and 16 is connected downstream of the hydrostatic transmission 2 as a mechanical transmission device. The output shaft 20 of the coupling system 12 is rotatably fixed to the differential 22 of the drive shaft, which rotates a predetermined number of wheels 24 (four in this particular case).
[0032] The coupling system 12 has a hydraulic coupling 26 having a first coupling section 28 non-rotatably connected to a first drive shaft 14 via a gear structure and a second coupling section 30 non-rotatably connected to a second drive shaft 16. In the exemplary embodiment shown, the clutch 26 is designed as a multi-plate clutch.
[0033] The piston 32 of the hydraulic cylinder 34 is connected to the second coupling section 30 to actuate the hydraulic coupling 26. Figure 1 In the exemplary embodiment shown, the hydraulic coupling 26 is designed as a negative clutch, which means that the hydraulic coupling 26 is actuated or closed when the actual pressure p of the cylinder chamber 36 defined by the piston 32 is lower than a predetermined value, which, among other things, depends on the spring force from the clutch spring 38.
[0034] Cylinder chamber 36 is connected via pressure medium line 40 to a first pressure medium connection 42 of pressure control device 44, which is configured as a pressure control valve. Additionally, cylinder chamber 36 is connected to a flushing line to allow the release of oil contained within the cylinder chamber under maximum pressure (e.g., 20 bar).
[0035] The second pressure medium connection 46 of the pressure control device 44 is connected to the pressure medium source 48, and the third pressure medium connection 50 is connected to the pressure medium tank T. The tank T has a temperature detection unit 52, through which the temperature of the pressure medium can be detected.
[0036] As an additional sensor system, a pressure detection unit 54 is provided, which is designed as a pressure sensor to detect the pressure in the pressure medium line 40. Additionally, a first speed detection unit 56 is provided, which can detect the actual speed of shaft 18, and, knowing the transmission ratio between shaft 18 and the first drive shaft 14, can determine the actual speed of the first drive shaft 14, and thus the actual speed n1 of the first coupling section 28. Furthermore, the transmission device 1 has a second speed detection unit 58, which can detect the actual speed of the second drive shaft 16, and, knowing the gear ratio between the second drive shaft 16 and the second clutch section 30, can determine the actual speed n2 of the second clutch section 30.
[0037] In order to control the actuation of the clutch 26, the hydrostatic drive 1 has a control unit 60, which has a memory unit 62 and a processor unit 64.
[0038] Temperature detection unit 52 is connected to control unit 60 via signal line 66, pressure detection unit 54 via signal line 68, first speed detection unit 56 via signal line 70, and second speed detection unit 58 via signal line 72.
[0039] The control unit 60 is connected to the regulating device 76 via the signal line 74, through which the stroke volume of the second hydraulic press 8 can be adjusted.
[0040] The pressure control device 44 has an electromagnet 78 connected to the control unit 60 via a signal line 80. The valve body of the pressure control device 44 is actuated in the direction of pressure medium connection from the first pressure medium connection 42 to the second pressure medium connection 46 by means of current supplied to the electromagnet 78 via the signal line 80. In the opposite direction to the actuation direction of the clutch 26 (in the case of the negative clutch shown), the valve body is actuated by the spring force of the spring 82 and the actual pressure p in the cylinder chamber 36 at the first pressure medium connection 42.
[0041] In the following text, see references Figures 2 to 4 The description will be used for Figure 1 The calibration method of the system disclosed in the document.
[0042] This calibration method is typically performed on each vehicle at end-of-life (EOL) and during commissioning, and can be requested by the operator each time. Calibration is also recommended after a specific number of operating hours (to be defined by the transmission and machine manufacturers), after the driver notices poor driving performance, or after repairs to the hydrostatic unit or the transmission's clutch circuit.
[0043] As described in the previous paragraphs, when the pressure control device 44 is not energized, the pressure in the cylinder chamber is the maximum achievable value and almost corresponds to the system charging pressure at the pressure medium source 48. For example, the pressure can be a value between 27 bar and 30 bar. As the current through the signal line 80 increases, the pressure in the cylinder chamber 36 begins to decrease.
[0044] At the start of the calibration process, the system's venting process is performed.
[0045] In particular, in order to remove any possible air from the pressure medium line, from the pressure control device 44, and from the hydraulic cylinder 34, the coupling system 12, and especially its clutch 26, is engaged and disengaged several times by operating the pressure control device 44. The number of times the clutch 26 is engaged and disengaged to perform the venting process can be greater than ten times, preferably equal to fifteen times.
[0046] During this exhaust process, the diesel engine output speed is monitored, preferably between 1100 rpm and 1300 rpm, the vehicle's parking brake is activated, both the permanent and temporary motor speeds are equal to 0, and the current of the pressure control device is controlled in a rectangular wave cycle. During this exhaust process, the temperature of the pressure medium, as measured by sensor 52, remains almost constant.
[0047] During this venting process, and specifically corresponding to the last X times (where X is preferably greater than four, more preferably equal to five) the coupling system 12 is closed and reopened, a first time interval t1 is measured. The first time interval t1 is the time required to reach a predetermined pressure value inside the hydraulic cylinder 34. This predetermined pressure is the pressure at which the first coupling section 28 has not yet fully engaged with the second coupling section 30 (has not yet reached the engagement point).
[0048] The predetermined pressure is determined by the following steps: measuring the pressure inside the hydraulic cylinder 34 when the first coupling section 28 is fully engaged with the second coupling section 30 (where torque is transmitted), and selecting a value for the pressure inside the hydraulic cylinder 34 when the first coupling section 28 is not fully engaged with the second coupling section 30, wherein the absolute value of the pressure difference between the predetermined pressure and the initial pressure value when the first coupling section 28 is fully engaged with the second coupling section 30 is equal to the predetermined value (e.g., equal to 4 bar).
[0049] As will be explained more clearly in the course of this instruction manual, during the calibration process, it is important to estimate the first time interval t1 as a function of the temperature of the pressure medium so that the value of the first time interval t1 can be estimated for each temperature of the pressure medium.
[0050] refer to Figure 2 and Figure 3 Let me explain in detail the process used to determine the first time interval t1 (referred to as the "drain time" from now on).
[0051] Figure 2 The pressure value (solid line) measured by sensor 54 and the current value (dashed line) delivered to electromagnet 78 via signal line 80 during the closure of coupling system 12 are shown. In this particular example, the predetermined pressure is considered to be equal to 12 bar. Figure 2 As shown, the current i delivered to the actuator 78 of the pressure control device 44 is increased. CSubsequently, the pressure begins to decrease with a certain delay (wherein this delay depends on the temperature of the pressure medium). After a certain period of time, a steady state is reached. After a certain period of time, a strong pressure gradient appears, which is caused by the approach to the junction. A predetermined pressure value is obtained along this pressure drop (e.g., at the midpoint between the pressure value at full engagement and the pressure value at the steady state before the strong pressure gradient appears).
[0052] Therefore, the venting time t1 will be considered as the time and current i when the predetermined pressure value is reached. C The time difference between the times that have been added ( Figure 2 (t1_f-t1_s).
[0053] As described above, it is preferable to measure the evacuation time t1 five times and then calculate the average value.
[0054] Figure 3 An overview of a method for estimating an interpolation function that represents the venting time t1 as a function of temperature is given, enabling the venting time to be estimated for each temperature of the pressure medium.
[0055] The average venting time is calculated for two different temperatures of the pressure medium, as described above: including the low-temperature T between 20°C and 40°C. L and including high temperature T between 60°C and 90°C H .
[0056] The offset value is used to correct the average calculated for both high and low temperatures of the pressure medium, by subtracting the offset value from the calculated average. The offset value is a function of the pressure medium's temperature and is due to the fact that the viscosity of the pressure medium has a greater effect at lower temperatures. As will become clearer as this specification progresses, this offset value is important for having more degrees of freedom on the way to the engagement point (so that a modulation phase can be allowed before the clutch closes). The offset value can be obtained as a function of tests conducted in different machines and at different temperatures of the pressure medium.
[0057] Equation 1
[0058]
[0059]
[0060] Where t 1_L_M and t 1_H_M These are the low-temperature and high-temperature averages calculated for the venting time t1, respectively, where t1 is the venting time for each measurement. off_L and t off_H These are the offset values for low temperature and high temperature values, respectively.
[0061] Based on t 1_L_M and t 1_H_M The value of t1 can be used to derive a function of t1. In this particular example, since t1 has been estimated for only two temperatures, the interpolation function is linear. In alternative embodiments, it is also possible to estimate the value of t1 for more temperature values and obtain a polynomial interpolation function of order n (where n is the number of temperatures for which t1 is estimated).
[0062] In this specific embodiment, the interpolation function contains the following:
[0063] Equation 2
[0064]
[0065] Where t1(T) is the interpolation function, which depends on the temperature T; t 1_L_M and t 1_H_M These are the lower and higher average values calculated for the venting time t1, respectively. These average values were calculated in the previous step using Equation 1. L and T H It is to calculate t 1_L_M and t 1_H_M The temperature of the pressure medium in which it is located.
[0066] After the interpolation function has been calculated for the evacuation time t1, this disclosure describes the determination of the junction point. It will be noted that this step can be performed simultaneously with the determination of the evacuation time t1.
[0067] Figure 4 An overview of methods for detecting joints is given.
[0068] Figure 4 The graph is divided into three parts. The upper part shows the changes in the speed n2 of the temporary motor 8 and the speed n1 of the permanent motor 4 over time, where n2... M Indicates the upper limit of the speed n2 of the temporary motor. Figure 4 The middle section shows the current i delivered by the control unit 60 to the electromagnet 78 via the signal line 80. C The value that changes over time, where iC M Indicator current i C The upper limit. Figure 4 The lower part shows the value of the pressure Δp delivered by the hydraulic press (not shown) given in the hydrostatic transmission device (which includes a permanent motor 4 and a temporary motor 6).
[0069] like Figure 4As shown in the upper part, to determine the engagement point, the rotational speed n1 of the permanent motor 4 is equal to 0, and the speed n2 of the temporary motor 8 is preferably equal to 500 rpm. At the same time, an upper limit value n2 for the speed n2 of the temporary motor 8 is given. M (For example, equal to 700 rpm), so that the speed n2 of the temporary motor 8 can be monitored to not exceed the upper limit. In addition, during this process, the diesel engine speed is controlled to preferably be between 1100 rpm and 1300 rpm, and the flow rate of the temporary motor 8 is preferably less than 20% of the maximum flow rate, so as to avoid high frictional torque at the clutch during calibration, thereby avoiding reduced cycle life of parts due to wear of the friction plates.
[0070] like Figure 4 As shown in the middle section, the current i delivered to the electromagnet 78 starts from the current value before the connection process has started (e.g., at 315mA). C The current gradually increases, causing the coupling system 12 to begin closing and the second coupling section 30 to approach the first coupling section 28. C The slope can be, for example, equal to 2.7 mA / s. Preferably, the slope is chosen such that the first coupling section and the second coupling section approach each other at an almost constant speed. As described above, iC M Indicator current i C The upper limit value, for example, is equal to 450mA. If it equals iC M If the system still hasn't reached the engagement point even when the value is specified, the calibration process will be terminated for safety reasons.
[0071] After a certain period of time, by gradually increasing the current i C The pressure Δp delivered by the hydraulic press begins to increase. After a certain period of time, due to friction between the first coupling section 28 and the second coupling section 30, the speed of the temporary motor n2 begins to decrease.
[0072] When the speed n2 of the temporary motor 8 is reduced / braked by approximately a predetermined amount, it can be considered that the engagement point has been reached. The inventors have discovered that in some applications, when the speed decreases by approximately 50 rpm (Δn = 50 rpm), the engagement point can be considered to have been reached. When said Δn has been reached, the actual current i is detected. C And temporarily save this value. Alternatively, the engagement point can also be detected by the following steps: measuring the pressure Δp delivered by the hydraulic press, and assuming that the engagement point has been reached when a predetermined Δp has been delivered. Therefore, when said Δp has been reached, the actual current i is detected. C And temporarily save the value.
[0073] This operation is repeated three times for at least two different temperatures of the pressure medium. Preferably, these temperatures are the same as those used to calculate the venting time. Specifically: low temperature T L Including temperatures between 20°C and 40°C, and high temperature T H This includes temperatures between 60°C and 90°C.
[0074] Based on the current i detected at the junction at two different temperatures C The value of can be used to derive the current i at the junction. C The function. In this particular example, because only two temperature measurements i have been taken... C Therefore, the interpolation function is a linear function. In alternative embodiments, it is also possible to measure this value for more temperature values and obtain an nth-order interpolation (where n is the estimated value of i). C A polynomial interpolation function for the number of temperatures being tested.
[0075] As described above, if in current i C The value is equal to i CM If the engagement point has not been reached by the specified conditions, the system will abort the calibration process for safety reasons. Similarly, if the speed n2 of the temporary motor 8 exceeds the upper limit n2 of the speed n2, the calibration process will also be terminated. M If the system fails to calibrate properly, the calibration process is terminated for safety reasons. Furthermore, the pressure difference Δp of the hydrostatic unit must be observed to ensure that the torque transmitted from the temporary motor 8 during engagement point testing does not exceed the permissible value. This is a requirement of the gearbox manufacturer to prevent damage to the clutch disc during calibration. At the start of the test, where the temporary motor 8 rotates at 500 rpm (in the example described above), the pressure difference Δp is measured. i When the engagement point is detected, the pressure difference will be higher due to the braking of the temporary motor, and Δp will be detected. k The important thing is to satisfy the following equation:
[0076] Equation 3
[0077] Δp k -Δp i ≤Δp T
[0078] Where, Δp T This is a threshold value, which must be defined based on the size of the motor, for example, corresponding to 20 Nm. Therefore, if the requirements of Equation 3 are no longer met during the contact point detection, the diagnostic function must abort the calibration process.
[0079] refer to Figure 5 and Figure 6 Two alternative methods for controlling the coupling system 12 are described. Figure 5 and Figure 6Both are divided into three parts. The upper part shows the current i. C The values change over time. In the middle section, the speed n1 (solid line) of the permanent motor 4 and the speed n2 (dashed line) of the temporary motor 8 are shown as changes over time. In the lower section, the displacement V of the temporary motor 8 is shown. g (Charted by dashed lines) Values that change over time.
[0080] It should be noted that, given the above description, after the actual temperature of the pressure medium has been detected, the venting time t1 and the current i at which the junction will be reached are known. C (i_kp) Both.
[0081] Control of the coupling system 12, and particularly the first coupling section 28 and the second coupling section 30, is achieved by controlling the current i supplied to the actuator 78 of the pressure control device 44. C This is implemented and will be completed when a downshift is requested, depending on the vehicle speed and the position of the drive pedal.
[0082] When shifting from second gear to first gear, the temporary motor 8 must accelerate from 0 rpm to a speed that depends on the speed of the permanent motor 4.
[0083] Therefore, the first coupling section 28 and the second coupling section 30 should be moved quickly to a position close to the engagement point. For example... Figure 5 As shown in the upper part, this occurs in the venting stage t1, which has been described above. Then, in the modulation stages t2 and t3, the first coupling section 28 and the second coupling section 30 will be slowly closed (current i C (The current is lower than during t1). During the modulation phases t2 and t3, the approach of the first coupling section 28 and the second coupling section 30 is slower relative to the approach during the emptying phase t1. Therefore, the modulation phases t2 and t3 can be simply referred to as the "modulation time", during which the engagement point is reached.
[0084] The gradients for modulation stages t2 and t3 are different to provide flexibility for different clutch system designs. Points 3 and 4 are based on the current i at the engagement point. C The calculated value (i_kp) is given. For example, the current in point 3 can be equal to i_kp-5mA, and the current in point 4 can be equal to i_kp-3mA. Furthermore, point 5 can also be determined based on i_kp. For example, the current in point 5 can be equal to i_kp+7mA.
[0085] When the final engagement point is reached, temporary motor 8 (see...) Figure 5The middle section will accelerate until it reaches a speed where the speed difference between the first coupling section 28 and the second coupling section 30 is less than a predetermined value Δn_t, for example, Δn_t equals 20 rpm (at point 5, the following condition Δn ≤ Δn_t is satisfied). At this point, the clutch will be fully engaged (current i C (The speed difference will increase suddenly). However, if the speed difference between the first coupling section 28 and the second coupling section 30 at point 5 is higher than the predetermined value, the clutch will fully re-engage for safety reasons.
[0086] Finally, if the pressure in cylinder chamber 36 is less than a predetermined value (e.g., 8 bar), then temporary motor 8 (see...) Figure 5 The lower part will be allowed to swivel out and the temporary motor displacement V g It will increase continuously.
[0087] In alternative embodiments, to accelerate the connection process, such as Figure 6 As shown, the clutch will be fully engaged earlier. Specifically, if the speed n2 of the temporary motor 8 is greater than the threshold and if the speed gradient of the temporary motor is greater than 0 (speed n2 is increasing), the clutch will be engaged (current i C (It will suddenly increase at point 5'). Additionally, if the pressure in cylinder chamber 36 is less than a predetermined value (e.g., 8 bar) and the speed difference between the first coupling section 28 and the second coupling section 30 is less than 20 rpm, then the temporary motor 8 (see...) Figure 6 The lower part will be allowed to rotate out and the temporary motor displacement V g It will increase continuously.
[0088] As in Figure 4 As shown in the comparison at the lower part, in this particular embodiment, the temporary motor displacement V g relative to Figure 5 The embodiments shown (dashed lines) are added earlier.
[0089] Although the invention has been described with reference to the embodiments described above, it will be apparent to those skilled in the art that various modifications, variations and improvements may be made to the invention in accordance with the teachings described above and within the scope of the appended claims without departing from the spirit and scope of the invention.
[0090] For example, even though only a working example for a negative clutch has been described in detail, it is clear that the present invention can also be used in a positive clutch and has the same technical advantages.
[0091] In addition, areas that are familiar to those skilled in the art are not described herein in order to avoid unnecessarily confusing the described invention.
[0092] Therefore, the present invention is not limited to the specific illustrated embodiments, but only to the scope of the appended claims.
Claims
1. A method for controlling a coupling system (12) of a superimposed mechanical transmission, the coupling system being configured to couple a first drive shaft (14) and a second drive shaft (16) during coupling, the coupling system (12) comprising a hydraulic coupling (26) having two releasable coupling sections (28, 30), wherein, A first coupling section (28) is connected to the first drive shaft (14) and a second coupling section (30) is connected to the second drive shaft (16). The coupling system (12) further includes a hydraulic cylinder (34) connected to one of the first coupling section (28) and the second coupling section (30) and configured to engage and disengage the first coupling section (28) and the second coupling section (30) based on pressure within the hydraulic cylinder (34). The pressure within the hydraulic cylinder (34) can be adjusted by means of a pressure regulating device (44). The pressure regulating device (44) includes an activation device (78) configured to operate based on a current (i) supplied to the activation device (78). C The method includes the following steps: ) to adjust the pressure inside the hydraulic cylinder (34); a. providing a current (i C ) to the activation means (78) for a first time interval (t1) such that the first coupling section (28) and the second coupling section (30) approach each other but have not yet reached the engagement point; b. after the first time interval (t1), current (i C ) is provided to the activation means (78) for a modulation time interval (t2, t3) such that the approach velocity of the first coupling section (28) and the second coupling section (3) is slowed down relative to the approach during the first time interval (t1), wherein the joint is reached during the modulation time interval (t2, t3); The method is characterized in that the modulation time interval (t2, t3) is divided into a second time interval (t2) and a third time interval (t3), wherein, in both the second time interval (t2) and the third time interval (t3), the current (i) supplied to the activation device (78) is... C The current (i) is gradually increased or decreased at a predetermined slope, wherein the current (i) C The slope of the current (i) during the second time interval (t2) relative to the current (i) C The slope is different during the third time interval (t3).
2. The method of claim 1, wherein, The current (i C The slope during the second time interval (t2) is less than that of the current (i). C The slope during the third time interval (t3).
3. The method of claim 1 or 2, wherein, When the speed difference between the first coupling section (28) and the second coupling section (30) is below a predetermined value (Δn_t), the third time interval (t3) is ended and a current (i C ) is supplied to the activation means (78) so that the first coupling section (28) and the second coupling section (30) are fully engaged with each other.
4. The method of claim 1 or 2, wherein, The first drive shaft (14) is connected to the first hydraulic motor (4) and the second drive shaft (16) is connected to the second hydraulic motor (8), wherein the first hydraulic motor (4) and the second hydraulic motor (8) are motors of a hydraulic transmission device.
5. The method of claim 1 or 2, wherein, The coupling system is a mechanical transmission device of the vehicle, positioned between a hydrostatic transmission device comprising multiple motors (4, 8) and the output shaft (20) of the superimposed mechanical transmission device.
6. The method according to claim 1 or 2, wherein, The first time interval (t1) is the time used during the engagement process, during which the first coupling section (28) and the second coupling section (30) will engage with each other, wherein during the first time interval (t1), the first coupling section (28) and the second coupling section (30) approach each other at the beginning of the engagement process, and then the approach of the first coupling section (28) and the second coupling section (30) is slowed down during the second time interval (t2).
7. The method of claim 1 or 2, wherein, The activating device is an electromagnet.