Method and computer program product for adjusting fork position of vehicle gearbox

Abstract

The invention provides a method and a computer program product for adjusting the position of a shift fork of a vehicle gearbox. The method comprises the steps that the distance between a shifting fork and a reference point is monitored, and the reference point is the center position between a first-gear gear and a second-gear gear; comparing the distance with a first distance threshold; and if the distance is smaller than a first distance threshold value, the torque transmitted by the two-gear gearbox is reduced. By means of the method, the shifting fork assembly deviating from the full-tooth-width joint position can be rapidly adjusted to the full-tooth-width joint position, and therefore it is ensured that a vehicle gearbox can transmit the torque as large as possible to the wheel end of a vehicle from a motor, and meanwhile the accidental out-of-gear fault of the vehicle is avoided.

Description

Technical Field

[0001] This invention relates to the field of vehicle transmission technology, and more specifically to a method for adjusting the position of a shift fork in a vehicle transmission. This method aims to ensure that the shift fork assembly and the gear are in full-width engagement, and to prevent unexpected gear disengagement. The invention also relates to a computer program product comprising program instructions that, when executed on a processor, cause the processor to perform the above-described method. Background Technology

[0002] In a vehicle's transmission system, torque can only be smoothly transmitted from the motor to the gear end via the shift fork assembly and the gear when the shift fork assembly is fully engaged with the engagement teeth of a gear at its full tooth width. If the engagement is poor, for example, if the shift fork assembly engages only partially with the engagement teeth, the transmitted torque will be limited, or other measures may be needed to protect the transmission system. Otherwise, the transmission system is likely to suffer mechanical damage.

[0003] On the other hand, during torque transmission, if no protective action is taken to return the shift fork assembly from the partial tooth width engagement position to the full tooth width engagement position, the shift fork assembly will typically float and move closer and closer to the "neutral" position, potentially leading to unexpected gear disengagement. Moreover, the greater the transmitted torque, the greater the risk of unexpected gear disengagement. This is dangerous and highly undesirable.

[0004] It is against the background described above that this invention was proposed. Summary of the Invention

[0005] To address one or more problems existing in the prior art, this invention proposes a method and computer program product for adjusting the position of the shift fork in a vehicle transmission. The method proposed in this invention can quickly adjust a shift fork assembly that has deviated from the full tooth width engagement position back to the full tooth width engagement position, thereby ensuring that the vehicle transmission can transmit the maximum possible torque from the motor to the vehicle wheels, while preventing unexpected gear slippage.

[0006] Specifically, in a first aspect of the invention, a method for adjusting the position of a shift fork in a vehicle transmission is provided. The vehicle transmission is a two-speed transmission, including a first gear and a second gear, and the shift fork is configured to engage with either the first gear or the second gear. The method includes: monitoring the distance between the shift fork and the reference point, wherein the reference point is the center position between the first gear and the second gear; comparing the distance with the first distance threshold; and if the distance is less than the first distance threshold, reducing the torque transmitted by the two-speed transmission.

[0007] In a second aspect of the invention, a method is provided for adjusting the position of a shift fork in a vehicle transmission, the transmission including a gear, the shift fork being configured to engage with the gear, wherein the method includes: monitoring the engagement status between the shift fork and the gear; and reducing the torque transmitted by the transmission if the distance between the shift fork and the gear is greater than or equal to a fifth distance threshold.

[0008] In a third aspect of the invention, a computer program product is provided, the computer program product comprising a computer program, the computer program comprising program instructions, wherein, when the program instructions are executed by a processor, the processor causes the processor to implement the method described in the first aspect.

[0009] Generally speaking, the various embodiments of the present invention can be combined and coupled in any possible manner within the scope of the invention. These and other aspects, features, and / or advantages of the invention will become apparent and will be elucidated with reference to the embodiments described below. Attached Figure Description

[0010] Embodiments of the invention will be described by way of example only with reference to the following accompanying drawings, in which:

[0011] Figure 1a The diagram schematically illustrates a vehicle's two-speed transmission, with the transmission's shift fork assembly in the full-width engagement position.

[0012] Figure 1b schematically illustrated Figure 1a The two-speed gearbox shown has its shift fork assembly in a partially tooth-width engagement position; and

[0013] Figure 2 The diagram schematically illustrates torque limiting curves applied to a transmission, based on which a method for adjusting the shift fork position of a vehicle transmission according to an embodiment of the present invention can be implemented.

[0014] It should be understood that the accompanying drawings only illustrate certain specific embodiments of the invention and should not be construed as limiting other possible embodiments falling within the scope of the appended claims. The scope of protection of the invention is defined only by the appended claims. Detailed Implementation

[0015] Figure 1a The diagram schematically illustrates a two-speed transmission for a vehicle, wherein the shift fork assembly 30 of the transmission is in full-width engagement with the second gear 12. Figure 1b schematically illustrated Figure 1a The two-speed gearbox shown has a shift fork assembly 30 that is in a partially tooth-width engagement state with the second gear 12.

[0016] like Figure 1a and Figure 1b As shown, the two-speed gearbox includes a first gear 11 (also referred to as the first gear 11) and a second gear 12 (also referred to as the second gear 12) mounted on the first gear shaft 10, which can be collectively referred to as the gearbox gears. The first gear 11 has a first gear engagement tooth 13 fixedly provided on its side facing the second gear 12, and the second gear 12 has a second gear engagement tooth 14 fixedly provided on its side facing the first gear 11. The two-speed gearbox also includes a third gear 21 and a fourth gear 22 mounted on the second gear shaft 20. The third gear 21 meshes with the first gear 11, and the fourth gear 22 meshes with the second gear 12. The two-speed gearbox also includes a shift fork assembly 30. The shift fork assembly 30 is disposed between the first gear 11 and the second gear 12, and includes a shift fork 31 and a synchronizer sleeve 32. Synchronizer sleeve 32 is fitted onto the first gear shaft 10 and engaged with the shift fork 31, so as to move between the first gear 11 and the second gear 12 as the shift fork 31 moves. The output shaft of the vehicle's motor 40 is connected to the first gear shaft 10 to transmit torque to the first gear shaft 10. Furthermore, the second gear shaft 20 is connected to the vehicle's wheel 50 to transmit the motor torque through the gearbox to the vehicle's wheel ends. Those skilled in the art will understand that the aforementioned two-speed gearbox will also include various other types of components. To avoid unnecessarily obscuring the focus of the invention, descriptions of these components will be omitted.

[0017] When the shift fork assembly 30 moves to engage with the first gear 11, the first gear shaft 10 drives the first gear 11 to rotate as the motor 40 operates. The first gear 11 meshes with the third gear 21, causing the third gear 21 to rotate, which in turn drives the second gear shaft 20 to rotate. In this way, torque is transmitted to the vehicle's wheels 50 at a first gear ratio. When the shift fork assembly 30 moves to engage with the second gear 12, the first gear shaft 10 drives the second gear 12 to rotate. The second gear 12 meshes with the fourth gear 22, causing the fourth gear 22 to rotate, which in turn drives the second gear shaft 20 to rotate. In this way, torque is transmitted to the vehicle's wheels 50 at a second gear ratio.

[0018] Figure 1a The schematic diagram illustrates the full-width engagement of the shift fork assembly 30 and the second gear 12. Figure 1bThe diagram schematically illustrates a partial tooth width engagement state between the shift fork assembly 30 and the second gear 12. "Full tooth width engagement" refers to the synchronizer sleeve 32 of the shift fork assembly 30 engaging with the second gear engagement tooth 14 of the second gear 12 across the entire tooth width. In this state, the shift fork assembly 30 moves to the left (in the illustrated orientation) to a position of, for example, 8.5 mm, where the center position between the first gear 11 and the second gear 12 is taken as the origin O of the horizontal axis. In the full tooth width engagement state, the engagement between the shift fork assembly 30 and the second gear 12 is very tight, enabling 100% transmission of the desired torque without causing mechanical damage to the transmission. In contrast, "partial tooth width engagement" refers to the synchronizer sleeve 32 of the shift fork assembly 30 engaging with the second gear engagement tooth 14 of the second gear 12 across only a portion (e.g., 50%) of the tooth width. At this point, the shift fork assembly 30 moves to the left along the horizontal axis to, for example, 7.5 mm, which is 1 mm away from the full tooth width engagement position shown in Figure 1. Figure 1b As shown by distance A in the diagram. In, for example, a 50% engagement state, only a portion of the desired torque can be transmitted, and the shift fork assembly 30 will float during torque transmission, getting closer and closer to the center position indicated by the origin 0 on the horizontal axis, thus causing unexpected disengagement. The greater the torque transmitted by the gearbox, the greater the risk of unexpected disengagement. Although... Figure 1a and Figure 1b The engagement between the shift fork assembly 30 and the second gear 12 is used as an example to illustrate the full tooth width engagement position and the half tooth width engagement position. However, those skilled in the art will understand that the above description also applies to the engagement between the shift fork assembly 30 and the first gear 11.

[0019] Based on this, the present invention proposes a method for adjusting the position of the shift fork in a vehicle transmission. The basic inventive concept of this method lies in rapidly adjusting the shift fork assembly 30, which has deviated from the full-width engagement position, back to the full-width engagement position by reducing the torque applied to the transmission. This ensures that the vehicle transmission can transmit the maximum possible torque from the motor 40 to the wheel 50, while simultaneously preventing unexpected gear slippage. The following will refer to... Figure 2 Describe the details of this method. Figure 2 The diagram schematically illustrates torque limiting curves C1, C2, and C3 applied to a transmission, based on which the method for adjusting the shift fork position of a vehicle transmission according to the present invention can be implemented. Those skilled in the art will understand that the torque limiting curves are merely an example of how to represent the mapping relationship between the shift fork position and the torque limit, and that this mapping relationship can be presented in any suitable manner, such as in the form of a lookup table.

[0020] exist Figure 2 In the diagram, the horizontal axis represents the distance of the shift fork assembly 30 from the origin (in...). Figure 1a and Figure 1b In the two-speed transmission shown, the origin is the distance between the center position of first gear 11 and second gear 12. The vertical axis represents the torque transmitted through the transmission (specifically, the engagement between the shift fork assembly 30 and the shift gear 11 or 12). The torque limiting curve C1 represents the torque limiting curve applied during shifting or engaging operations based on the mechanical capabilities of the transmission. It shows the torque allowed to be transmitted through the transmission during shifting or engaging operations when the shift fork assembly 30 is at different distances from the origin (i.e., when the shift fork assembly 20 is in different engagement states with the gear 11 or 12).

[0021] First, a detailed description Figure 2 The torque limiting curve C1 is shown. (As shown...) Figure 2 As shown, when the horizontal axis is 0–4.3 mm (i.e., when the shift fork assembly 30 is 0–4.3 mm from the origin), the vertical axis of the torque limiting curve C1 is 0. It can be understood that the horizontal axis of 0–4.3 mm indicates that the shift fork assembly 30 is in neutral, at which point the shift fork assembly 30 is not engaged with any of the gears 11 or 12, therefore the torque allowed to be transmitted through the shift fork assembly 30 and the gears 11 or 12 (i.e., the vertical axis) is 0. When the horizontal axis is 4.3–5.9 mm, the vertical axis of the torque limiting curve C1 is still 0. It can be understood that the horizontal axis of 4.3–5.9 mm indicates that the shift fork assembly 30 has just begun to engage with the gears 11 or 12, and for safety reasons, the torque allowed to be transmitted through the shift fork assembly 30 and the gears 11 or 12 is still 0. When the horizontal axis is 5.9–6.6 mm, the vertical axis of the torque limiting curve C1 gradually increases linearly from 240 to 450. It will be understood that a horizontal axis of 5.9–6.6 mm indicates a stronger engagement between the shift fork assembly 30 and the gear 11 or 12, allowing a certain proportion of the desired torque (e.g., 240–450) to be transmitted through the shift fork assembly 30 and the gear 11 or 12. When the horizontal axis is above 6.6 mm, the vertical axis of the torque limiting curve C1 remains constant at 450 until the shift fork assembly 30 enters the full tooth width engagement position (e.g., between 8.5 and 8.8 mm). It will be understood that a horizontal axis above 6.6 mm indicates a sufficiently strong engagement between the shift fork assembly 30 and the gear 11 or 12, allowing 100% of the desired torque to be transmitted through the shift fork assembly 30 and the gear 11 or 12. It will be understood that the specific values ​​described above are given only as exemplary embodiments and are not intended to limit the scope of the invention. Different values ​​may be selected in practical applications.

[0022] The torque limiting curve C1 mentioned above is the torque limiting curve applied during gear shifting or engaging operations. During operation after the gear shifting or engaging operation is completed, the shift fork assembly 30 may deviate from the full tooth width engagement position, and the distance from the origin may decrease to below a certain threshold. At this time, torque limiting curves C2 and C3 will be applied to operate the transmission to adjust the shift fork assembly 30, which has deviated from the full tooth width engagement position, back to the full tooth width engagement position, thereby preventing the vehicle from experiencing unexpected gear disengagement.

[0023] like Figure 2 As mentioned above, curves C2 and C3 are both within the envelope of curve C1. Curve C2 represents the torque allowed to be transmitted through the transmission when the shift fork assembly 30 (or shift fork or shift fork) is 6.6–8.5 mm from the origin. Curve C3 represents the control to re-engage the shift fork assembly 30 when it moves to a position less than 6.6 mm from the origin, so that the shift fork assembly 30 moves directly to the full gear width engagement position.

[0024] It will be understood that when the horizontal axis is above 8.5mm, for example, between 8.5mm and the furthest point of 8.8mm, the shift fork assembly 30 will be considered to be in the safe zone, where the shift fork assembly 30 is in the full tooth width engagement position. At this point, no additional measures are required. That is, the gearbox can be operated according to curve C1.

[0025] As the horizontal axis decreases from 8.5mm to 7.5mm, meaning the shift fork assembly 30 moves from a full-width engagement position to a partial-width engagement position, the engagement between the shift fork assembly 30 and the gear 11 or 12 gradually weakens, but remains in a relatively optimal engagement state. At this point, the vertical axis of curve C2 can be equal to a value less than 450 (e.g., 415Nm). By applying curve C2 to the transmission, the torque transmitted by the transmission can be reduced to a constant 415Nm. At this reduced torque of 415Nm, the shift fork assembly 30 will typically return to the full-width engagement position within a certain time period.

[0026] As the horizontal axis decreases from 7.5 mm to 7.2 mm, the engagement between the shift fork assembly 30 and the gear 11 or 12 continuously weakens and can be considered to be in a suboptimal engagement state. At this point, the aforementioned constant torque (e.g., 415 Nm) will be insufficient to return the shift fork assembly 30 to the full tooth width engagement position. Therefore, the vertical axis of curve C2 gradually decreases as the horizontal axis decreases from 7.5 mm to 7.2 mm, for example, from 415 Nm to 0. That is, the further the shift fork assembly 30 is from the safe zone, the smaller the torque allowed to be transmitted by the transmission. In a preferred embodiment, curve C2 in the range of 7.5 to 7.2 mm includes: a torque-increasing path portion (the curved portion with an upward arrow in the figure) applied during the gradual increase of torque transmitted by the transmission; and a torque-decreasing path portion (the curved portion with a downward arrow in the figure) applied during the gradual decrease of torque transmitted by the transmission, wherein both the torque-increasing and torque-decreasing path portions gradually decrease from 415 Nm to 0. Furthermore, the torque-increasing path portion lies below the torque-decreasing path portion; that is, at the same distance, the torque allowed to be transmitted by the transmission in the torque-increasing path is less than the torque allowed to be transmitted by the transmission in the torque-decreasing path. This will be understood as being caused by the time lag effect of applying torque limits.

[0027] In a preferred embodiment, the torque reduction path portion decreases from the aforementioned torque of 415 Nm at a gradually increasing smaller slope, then at a constant slope, and finally decreases to 0 at a gradually decreasing smaller slope. The torque increase path portion decreases from the aforementioned torque of 415 Nm at a gradually increasing larger slope, then at a constant slope, and finally decreases to 0 at a gradually decreasing larger slope. By applying either the torque increase path portion or the torque reduction path portion to the transmission according to the changes in torque transmitted by the transmission, the shift fork assembly 30 will typically return to the full tooth width engagement position within a certain time period.

[0028] As the horizontal axis decreases from 7.2mm to 6.6mm, the engagement between the shift fork assembly 30 and the gear 11 or 12 continues to weaken and can be considered to be in a poor engagement state. At this point, the vertical axis of curve C2 equals 0. By applying a zero torque limit to the transmission, torque transmission through the transmission is no longer permitted. In this way, the shift fork assembly 30 will typically return to the full tooth width engagement position within a certain period of time.

[0029] Furthermore, if the shift fork assembly 30 continues to move away from the safe zone to a position with a horizontal coordinate less than 6.6 mm, it indicates a critical situation. In this case, the gear can be re-engaged as indicated by curve C3 to quickly return the shift fork assembly 30 to the safe zone. Alternatively, if the shift fork assembly 30 remains within the application window of torque limiting curve C2 (i.e., within the horizontal coordinate range of 6.6–8.5 mm) for an excessively long time, for example, exceeding 60 seconds, it indicates that the applied torque limiting curve C2 is not functioning as expected. In this case, the gear can also be re-engaged as indicated by curve C3 to quickly return the shift fork assembly 30 to the safe zone. During re-engagement, the shift fork assembly 30 can first be disengaged from gear 11 or 12 to return to the center position, and then the shift fork assembly 30 can be moved back to the full gear width engagement position. The re-engagement indicated by curve C3, as a supplement to curve C2, serves as a second line of defense for adjusting the position of the shift fork assembly 30, effectively preventing unexpected gear disengagement.

[0030] The method for adjusting the shift fork position of a vehicle transmission according to the present invention will now be described in detail based on the above description of curves C2 and C3. It should be emphasized that this method is performed after the initial gear engagement or shifting operation of the transmission is completed.

[0031] First, the method includes step S1. In step S1, the distance between the shift fork and a reference point is monitored. In the case of a two-speed transmission, the reference point is preferably the center position between first gear 11 and second gear 12. In this way, the distances between first gear 11 and second gear 12 and the reference point are equal, and the distance between the shift fork and the reference point will equally reflect the engagement status between the shift fork and the gear, allowing the same control logic to be used to adjust the position of the shift fork in different gears. The shift fork can be moved from the reference point to a maximum distance (e.g., 8.8 mm). At this maximum distance, the shift fork is fully engaged with gear 11 or 12, i.e., in a full-tooth-width engagement state. This is desirable to ensure the proper operation of the transmission.

[0032] Then, the method includes step S2. In step S2, the distance is compared with a first distance threshold. If the distance is less than the first distance threshold, the torque transmitted by the two-speed transmission is reduced to increase the distance between the shift fork and the reference point to above the first distance threshold. The first distance threshold can be, for example, 8.5 mm, and the area between the first distance threshold and the aforementioned maximum distance can be considered a safe area. Within this safe area, the shift fork assembly 30 and the gear 11 or 12 can be considered to be in full-tooth-width engagement. If the comparison result indicates that the distance is less than the first distance threshold, it indicates that the shift fork assembly 30 has moved outside the safe area. At this time, by reducing the torque transmitted by the transmission, the contact pressure and friction between the shift fork assembly 30 and the gear can be reduced, thereby adjusting the shift fork assembly 30, which has deviated from the full-tooth-width engagement position, back to the full-tooth-width engagement position.

[0033] Step S2 of the method further includes: comparing the distance with a second distance threshold that is less than a first distance threshold; if the distance is less than the first distance threshold but above the second distance threshold, reducing the torque transmitted by the transmission includes: reducing the torque transmitted by the transmission to a constant first torque. The second distance threshold can be, for example, 7.5 mm, and the area between the second distance threshold and the aforementioned first distance threshold can be considered a preferred engagement area. Within this preferred engagement area, although the shift fork assembly 30 and the gear 11 or 12 are not in full-tooth-width engagement, they can still be considered to be in a preferred engagement state. The first torque can be, for example, 415 Nm. If the comparison result indicates that the distance is less than the first distance threshold but above the second distance threshold, the shift fork assembly 30, which has deviated from the full-tooth-width engagement position, can be adjusted back to the full-tooth-width engagement position by applying the first torque to the transmission.

[0034] Step S2 of the method further includes: comparing the distance with a third distance threshold that is less than a second distance threshold; if the distance is less than the second distance threshold but above the third distance threshold, reducing the torque transmitted by the transmission includes: reducing the torque transmitted by the transmission to a second torque, wherein the second torque gradually decreases as the distance decreases, and the maximum value of the second torque is equal to the first torque. That is, when the distance is equal to the second distance threshold, the second torque is equal to the first torque. Furthermore, when the distance is equal to the third distance threshold, the second torque can be 0. The third distance threshold can be, for example, 7.2 mm, and the area between the third distance threshold and the aforementioned second distance threshold can be considered a suboptimal engagement area. Within this suboptimal engagement area, the shift fork assembly 30 and the gear 11 or 12 can be considered to be in a suboptimal engagement state. If the comparison result indicates that the distance is less than the second distance threshold but above the third distance threshold, the second torque can be applied to the transmission to adjust the shift fork assembly 30, which has deviated from the full-width engagement position, back to the full-width engagement position.

[0035] In a preferred embodiment, in step S2, when the distance is less than a second distance threshold but above a third distance threshold, the second torque applied during the gradual increase of torque transmitted by the gearbox is less than the second torque applied during the gradual decrease of torque transmitted by the gearbox. In this way, the time lag effect of the applied torque limiting curve can be taken into account, allowing for a more efficient and rapid adjustment of the shift fork assembly 30, which has deviated from the full tooth width engagement position, back to the full tooth width engagement position.

[0036] Finally, the method includes step S3. In step S3, the distance is compared with a fourth distance threshold that is less than a third distance threshold. If the distance is less than the third distance threshold but above the fourth distance threshold, reducing the torque transmitted by the transmission includes reducing the torque transmitted by the transmission to a constant third torque, which is equal to the minimum value of the second torque. This third torque can be equal to 0. The fourth distance threshold can be, for example, 6.6 mm, and the area between the fourth distance threshold and the aforementioned third distance threshold can be considered a poor engagement area. Within this poor engagement area, the shift fork assembly 30 is in a poor engagement state with the gear 11 or 12. At this time, the shift fork assembly 30, which is deviating from the full tooth width engagement position, can be adjusted back to the full tooth width engagement position by applying a third torque equal to 0 to the transmission.

[0037] The above steps can be executed automatically during transmission operation without the driver's awareness, thus avoiding interference with driving. Because the electric motor's torque response is extremely rapid, the torque limiting curve can be applied within a very short time window (e.g., approximately 2 seconds). This means that the above steps can quickly adjust a shift fork that has deviated from the full tooth width engagement position back to the full tooth width engagement position, thereby achieving 100% torque transmission.

[0038] Furthermore, step S3 of the above method also includes: if the distance is less than a fourth distance threshold, controlling the shift fork to re-engage, wherein the shift fork is first moved to a reference point and then moved back a distance greater than the first distance threshold. This ensures that safe operation of the transmission can be quickly restored when the engagement between the shift fork assembly 30 and the gear 11 or 12 becomes poor.

[0039] Finally, the method includes step S4. In step S4, after reducing the torque transmitted by the gearbox, timing begins and the distance between the shift fork and the reference point is continuously monitored. If, after a predetermined time period, the distance is still less than a first distance threshold, the shift fork is controlled to re-engage, wherein the shift fork is first moved to the reference point and then moved back a distance greater than the first distance threshold. The predetermined time period can be 60 seconds.

[0040] Furthermore, if the distance is less than the fourth distance threshold or if it is determined that the distance is still less than the first distance threshold after a predetermined time period, an alarm may be issued to the driver first, and the alarm may be deactivated only when the distance is greater than or equal to the first distance threshold.

[0041] Re-engaging gears can act as a "firewall" to prevent gear slippage during vehicle operation, thereby improving driving safety. Similarly, this re-engaging operation can also be automatically performed by the vehicle controller, controlling relevant components. The aforementioned alarm is only intended to remind the driver of the vehicle's current operating status, prevent erroneous operation, help the driver control the vehicle more accurately, and enhance the driving experience.

[0042] In a second aspect of the invention, another method for adjusting the position of the shift fork in a vehicle transmission is provided. This method can be applied to two-speed transmissions, as well as transmissions with fewer or more gears.

[0043] Specifically, the method includes: monitoring the engagement between the shift fork and the gear; and reducing the torque transmitted by the transmission if the distance between the shift fork and the gear is greater than or equal to a fifth distance threshold. Monitoring the engagement between the shift fork and the gear includes: selecting any reference point, determining the positions of the gear and the shift fork relative to the reference point, thereby determining the distance between the gear and the shift fork. Those skilled in the art will understand that this reference point can be arbitrarily chosen for practical convenience; it is merely an intermediate bridge, and the ultimate goal is to determine the distance between the shift fork and the gear to determine their engagement. The determination of the relationship between the "distance between the shift fork and the gear" and the fifth distance threshold can be performed directly or indirectly. In the direct method, the distance between the shift fork and the gear is directly measured and compared with the fifth distance threshold. In the indirect method, a first quantity associated with the distance and a second quantity associated with the fifth distance threshold can be obtained, and then the first quantity and the second quantity can be compared. For example, the first quantity can be equal to the distance between the shift fork and the reference point indicating the neutral position, and the second quantity can be equal to the distance between the gear and the reference point minus the fifth distance threshold. By comparing the first quantity and the second quantity, the relationship between the "distance between the shift fork and the gear" and the fifth distance threshold can be obtained.

[0044] The method further includes: if the distance between the shift fork and the gear is greater than or equal to a fifth distance threshold but less than a sixth distance threshold, then the torque transmitted by the transmission is reduced to a constant first torque; if the distance between the shift fork and the gear is greater than or equal to a sixth distance threshold but less than a seventh distance threshold, then the torque transmitted by the transmission is reduced to a second torque, wherein the second torque gradually decreases as the distance increases, and the maximum value of the second torque is equal to the first torque; and if the distance between the shift fork and the gear is greater than or equal to a second distance threshold but less than an eighth distance threshold, then the torque transmitted by the transmission is reduced to a constant third torque, wherein the third torque is equal to the minimum value of the second torque. Furthermore, when the distance between the shift fork and the gear is greater than or equal to the sixth distance threshold but less than the seventh distance threshold, the second torque applied during the gradual increase of the torque transmitted by the transmission is less than the second torque applied during the gradual decrease of the torque transmitted by the transmission. This allows the time lag effect of applying the torque limiting curve to be taken into account.

[0045] Furthermore, the above method includes: if the distance between the shift fork and the gear is greater than or equal to an eighth distance threshold, then controlling the shift fork to re-engage, wherein the shift fork is first moved to the neutral position and then moved back toward the gear, so that the distance between the shift fork and the gear is less than a fifth distance threshold.

[0046] The above method also includes: after reducing the torque transmitted by the transmission, starting a timer and continuously monitoring the distance between the shift fork and the gear; if the distance is still greater than or equal to the fifth distance threshold after a predetermined time period, controlling the shift fork to re-engage, wherein the shift fork is first moved to the neutral position and then moved back to the gear, so that the distance between the shift fork and the gear is less than the fifth distance threshold.

[0047] The fifth, sixth, seventh, and eighth distance thresholds increase sequentially. Based on Figure 2 The disclosed torque limiting curves specify that the fifth distance threshold can be 0.3 mm, the sixth distance threshold can be 1.3 mm, the seventh distance threshold can be 1.6 mm, and the eighth distance threshold can be 2.2 mm. Those skilled in the art will understand that the aforementioned distance thresholds can be any other suitable value.

[0048] The methods and steps described above can all be automatically executed by the vehicle's transmission control unit (TCU). Those skilled in the art will understand that the TCU is an important electronic control unit in current vehicles, comprising inputs / outputs, one or more memories, and a processor. The inputs / outputs are used to receive information from other components and send control commands to other components; the memories are used to store program code; and the processor is used to execute this program code to achieve specific functions. Therefore, the method according to the present invention requires no additional hardware configuration; it can be implemented simply by updating the software code into an existing TCU.

[0049] In a third aspect of the invention, a computer program product is provided. This computer program product includes a computer program comprising instructions that, when executed by a processor, implement the aforementioned method for adjusting the position of the shift forks of a vehicle transmission. The advantages described above for the vehicle control method also apply to this computer program product.

[0050] The aforementioned computer program product can be stored on a storage medium. The storage medium can be volatile memory or non-volatile memory, or a combination of both. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which serves as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate Synchronous DRAM (DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The storage media described in this invention are intended to include, but are not limited to, these and any other suitable types of memory.

[0051] Although the invention has been described in conjunction with the specific embodiments described above, it should not be construed as limiting it in any way to the presented examples. The scope of the invention is defined by the appended claims. In the context of the claims, the terms "comprising" or "including" do not exclude other possible elements or steps. Furthermore, references such as "a" or "an" should not be construed as excluding multiple elements. The use of reference numerals for elements shown in the figures in the claims should also not be construed as limiting the scope of the invention. Moreover, various features mentioned in different claims may be advantageously combined, and mentioning these features in different claims does not preclude the impossibility and advantage of such combinations. Furthermore, the terms "first" through "eighth," etc., used throughout the invention are merely for distinguishing related components and are not intended to assign them any attribute of priority.

Claims

1. A method for adjusting the position of a shift fork in a vehicle transmission, the vehicle transmission being a two-speed transmission, the two-speed transmission including a first gear and a second gear, the shift fork being configured to engage with the first gear or the second gear, characterized in that, The method includes: Monitor the distance between the shift fork and a reference point, wherein the reference point is the center position between the first gear and the second gear; The distance is compared with a first distance threshold. If the distance is less than the first distance threshold, the torque transmitted by the two-speed gearbox is reduced.

2. The method according to claim 1, characterized in that, The method further includes: The distance is compared with a second distance threshold that is less than the first distance threshold. If the distance is less than the first distance threshold but above the second distance threshold, reducing the torque transmitted by the two-speed transmission includes reducing the torque transmitted by the two-speed transmission to a constant first torque.

3. The method according to claim 2, characterized in that, The method further includes: The distance is compared with a third distance threshold that is less than the second distance threshold; If the distance is less than the second distance threshold but above the third distance threshold, reducing the torque transmitted by the two-speed transmission includes: reducing the torque transmitted by the two-speed transmission to a second torque, wherein the second torque gradually decreases as the distance decreases, and the maximum value of the second torque is equal to the first torque.

4. The method according to claim 3, characterized in that, The second torque decreases from the first torque to 0 as the distance decreases.

5. The method according to claim 3, characterized in that, When the distance is less than the second distance threshold but above the third distance threshold, the second torque applied during the gradual increase of the torque transmitted by the two-speed transmission is less than the second torque applied during the gradual decrease of the torque transmitted by the two-speed transmission.

6. The method according to claim 3, characterized in that, The method further includes: The distance is compared with a fourth distance threshold that is less than the third distance threshold; If the distance is less than the third distance threshold but above the fourth distance threshold, reducing the torque transmitted by the two-speed transmission includes reducing the torque transmitted by the two-speed transmission to a constant third torque, wherein the third torque is equal to the minimum value of the second torque.

7. The method according to claim 6, characterized in that, The third torque is equal to 0.

8. The method according to claim 6, characterized in that, The method further includes: If the distance is less than the fourth distance threshold, the shift fork is controlled to re-engage, wherein the shift fork is first moved to the reference point, and then moved back a distance greater than the first distance threshold.

9. The method according to claim 1, characterized in that, The method further includes: After reducing the torque transmitted by the two gearboxes, timing begins and the distance between the shift fork and the reference point is continuously monitored; If the distance is still less than the first distance threshold after a predetermined time period, the shift fork is controlled to re-engage gears, wherein the shift fork is first moved to the reference point, and then moved back a distance greater than the first distance threshold.

10. The method according to claim 8 or 9, characterized in that, The method further includes: Before the shift fork is re-engaged, an alarm is issued to the driver, and the alarm is deactivated only when the distance is greater than or equal to the first distance threshold.

11. The method according to claim 6, characterized in that, The first distance threshold is equal to 8.5 mm, the second distance threshold is equal to 7.5 mm, the third distance threshold is equal to 7.2 mm, and the fourth distance threshold is equal to 6.6 mm.

12. A method for adjusting the position of a shift fork in a vehicle transmission, the transmission including a gearbox, the shift fork being configured to engage with the gearbox, characterized in that, The method includes: Monitor the engagement status between the shift fork and the gear; and If the distance between the shift fork and the gear is greater than or equal to a fifth distance threshold, the torque transmitted by the gearbox is reduced.

13. The method according to claim 12, characterized in that, Monitoring the engagement between the shift fork and the gear includes: Select any reference point to determine the position of the gear and the shift fork relative to the reference point, thereby determining the distance between the gear and the shift fork.

14. The method according to claim 12, characterized in that, The method further includes: If the distance between the shift fork and the gear is greater than or equal to the fifth distance threshold but less than the sixth distance threshold, the torque transmitted by the gearbox is reduced to a constant first torque.

15. The method according to claim 14, characterized in that, The method further includes: If the distance between the shift fork and the gear is greater than or equal to the sixth distance threshold but less than the seventh distance threshold, the torque transmitted by the gearbox is reduced to a second torque, wherein the second torque gradually decreases as the distance increases, and the maximum value of the second torque is equal to the first torque.

16. The method according to claim 15, characterized in that, The method further includes: If the distance between the shift fork and the gear is greater than or equal to the second distance threshold but less than the eighth distance threshold, the torque transmitted by the gearbox is reduced to a constant third torque, wherein the third torque is equal to the minimum value of the second torque.

17. The method according to claim 15, characterized in that, When the distance between the shift fork and the gear is greater than or equal to the sixth distance threshold but less than the seventh distance threshold, the second torque applied during the gradual increase of the torque transmitted by the gearbox is less than the second torque applied during the gradual decrease of the torque transmitted by the gearbox.

18. The method according to claim 16, characterized in that, The method further includes: If the distance between the shift fork and the gear is greater than or equal to the eighth distance threshold, the shift fork is controlled to re-engage, wherein the shift fork is first moved to the neutral position and then moved back toward the gear, so that the distance between the shift fork and the gear is less than the fifth distance threshold.

19. The method according to claim 12, characterized in that, The method further includes: After reducing the torque transmitted by the gearbox, timing begins and the distance between the shift fork and the gear is continuously monitored; If, after a predetermined time period, the distance is still greater than or equal to the fifth distance threshold, the shift fork is controlled to re-engage, wherein the shift fork is first moved to the neutral position and then moved back toward the gear, so that the distance between the shift fork and the gear is less than the fifth distance threshold.

20. A computer program product comprising a computer program, the computer program including instructions, characterized in that, When the instructions are processed, the processor causes the processor to implement the method according to any one of claims 1-19.

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